Skip to main content

wit_bindgen_cpp/
lib.rs

1use anyhow::bail;
2use heck::{ToPascalCase, ToShoutySnakeCase, ToSnakeCase, ToUpperCamelCase};
3use std::{
4    collections::{HashMap, HashSet},
5    fmt::{self, Display, Write as FmtWrite},
6    io::{Read, Write},
7    path::PathBuf,
8    process::{Command, Stdio},
9    str::FromStr,
10};
11use symbol_name::{make_external_component, make_external_symbol};
12use wit_bindgen_c::to_c_ident;
13use wit_bindgen_core::{
14    Files, InterfaceGenerator, Source, Types, WorldGenerator,
15    abi::{self, AbiVariant, Bindgen, Bitcast, LiftLower, WasmSignature, WasmType},
16    name_package_module, uwrite, uwriteln,
17    wit_parser::{
18        Alignment, ArchitectureSize, Docs, Function, FunctionKind, Handle, Int, InterfaceId,
19        Resolve, SizeAlign, Stability, Type, TypeDef, TypeDefKind, TypeId, TypeOwner, WorldId,
20        WorldKey,
21    },
22};
23
24// mod wamr;
25mod symbol_name;
26
27pub const RESOURCE_IMPORT_BASE_CLASS_NAME: &str = "ResourceImportBase";
28pub const RESOURCE_EXPORT_BASE_CLASS_NAME: &str = "ResourceExportBase";
29pub const RESOURCE_TABLE_NAME: &str = "ResourceTable";
30pub const OWNED_CLASS_NAME: &str = "Owned";
31pub const POINTER_SIZE_EXPRESSION: &str = "sizeof(void*)";
32
33type CppType = String;
34
35#[derive(Clone, Copy, Debug)]
36enum Flavor {
37    Argument(AbiVariant),
38    Result(AbiVariant),
39    InStruct,
40    BorrowedArgument,
41}
42
43#[derive(Default)]
44struct HighlevelSignature {
45    /// this is a constructor or destructor without a written type
46    // implicit_result: bool, -> empty result
47    const_member: bool,
48    static_member: bool,
49    result: CppType,
50    arguments: Vec<(String, CppType)>,
51    name: String,
52    namespace: Vec<String>,
53    implicit_self: bool,
54    post_return: bool,
55}
56
57// follows https://google.github.io/styleguide/cppguide.html
58
59#[derive(Default)]
60struct Includes {
61    needs_vector: bool,
62    needs_expected: bool,
63    needs_string: bool,
64    needs_string_view: bool,
65    needs_optional: bool,
66    needs_cstring: bool,
67    needs_imported_resources: bool,
68    needs_exported_resources: bool,
69    needs_variant: bool,
70    needs_tuple: bool,
71    needs_assert: bool,
72    needs_bit: bool,
73    needs_span: bool,
74    // needs wit types
75    needs_wit: bool,
76    needs_memory: bool,
77    needs_array: bool,
78}
79
80#[derive(Default)]
81struct SourceWithState {
82    src: Source,
83    namespace: Vec<String>,
84}
85
86#[derive(Eq, Hash, PartialEq, Clone, Copy, Debug)]
87enum Direction {
88    Import,
89    Export,
90}
91
92#[derive(Default)]
93struct Cpp {
94    opts: Opts,
95    c_src: SourceWithState,
96    h_src: SourceWithState,
97    c_src_head: Source,
98    extern_c_decls: Source,
99    dependencies: Includes,
100    includes: Vec<String>,
101    world: String,
102    world_id: Option<WorldId>,
103    imported_interfaces: HashSet<InterfaceId>,
104    user_class_files: HashMap<String, String>,
105    defined_types: HashSet<(Vec<String>, String)>,
106    types: Types,
107
108    // needed for symmetric disambiguation
109    interface_prefixes: HashMap<(Direction, WorldKey), String>,
110    import_prefix: Option<String>,
111}
112
113#[cfg(feature = "clap")]
114fn parse_with(s: &str) -> Result<(String, String), String> {
115    let (k, v) = s.split_once('=').ok_or_else(|| {
116        format!("expected string of form `<key>=<value>[,<key>=<value>...]`; got `{s}`")
117    })?;
118    Ok((k.to_string(), v.to_string()))
119}
120
121#[derive(Default, Debug, Clone)]
122#[cfg_attr(feature = "clap", derive(clap::Args))]
123pub struct Opts {
124    /// Call clang-format on the generated code
125    #[cfg_attr(feature = "clap", arg(long, default_value_t = bool::default()))]
126    pub format: bool,
127
128    /// Place each interface in its own file,
129    /// this enables sharing bindings across projects
130    #[cfg_attr(feature = "clap", arg(long, default_value_t = bool::default()))]
131    pub split_interfaces: bool,
132
133    /// Optionally prefix any export names with the specified value.
134    ///
135    /// This is useful to avoid name conflicts when testing.
136    #[cfg_attr(feature = "clap", arg(long))]
137    pub export_prefix: Option<String>,
138
139    /// Wrap all C++ classes inside a custom namespace.
140    ///
141    /// This avoids identical names across components, useful for native
142    #[cfg_attr(feature = "clap", arg(long))]
143    pub internal_prefix: Option<String>,
144
145    /// Set API style to symmetric or asymmetric
146    #[cfg_attr(
147        feature = "clap",
148        arg(
149            long,
150            default_value_t = APIStyle::default(),
151            value_name = "STYLE",
152        ),
153    )]
154    pub api_style: APIStyle,
155
156    /// Whether to generate owning or borrowing type definitions for `record` arguments to imported functions.
157    ///
158    /// Valid values include:
159    ///
160    /// - `owning`: Generated types will be composed entirely of owning fields,
161    ///   regardless of whether they are used as parameters to imports or not.
162    ///
163    /// - `coarse-borrowing`: Generated types used as parameters to imports will be
164    ///   "deeply borrowing", i.e. contain references rather than owned values,
165    ///   so long as they don't contain resources, in which case they will be
166    ///   owning.
167    ///
168    /// - `fine-borrowing": Generated types used as parameters to imports will be
169    ///   "deeply borrowing", i.e. contain references rather than owned values
170    ///   for all fields that are not resources, which will be owning.
171    #[cfg_attr(feature = "clap", arg(long, default_value_t = Ownership::Owning))]
172    pub ownership: Ownership,
173
174    /// Where to place output files
175    #[cfg_attr(feature = "clap", arg(skip))]
176    out_dir: Option<PathBuf>,
177
178    /// Importing wit interface from custom include
179    ///
180    /// Argument must be of the form `k=v` and this option can be passed
181    /// multiple times or one option can be comma separated, for example
182    /// `k1=v1,k2=v2`.
183    #[cfg_attr(feature = "clap", arg(long, value_parser = parse_with, value_delimiter = ','))]
184    pub with: Vec<(String, String)>,
185}
186
187/// Supported API styles for the generated bindings.
188#[derive(Default, Debug, Copy, Clone, PartialEq, Eq, Hash)]
189pub enum APIStyle {
190    /// Imported functions borrow arguments, while exported functions receive owned arguments. Reduces the allocation overhead for the canonical ABI.
191    #[default]
192    Asymmetric,
193    /// Same API for imported and exported functions. Reduces the allocation overhead for symmetric ABI.
194    Symmetric,
195}
196
197impl Display for APIStyle {
198    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
199        match self {
200            APIStyle::Asymmetric => write!(f, "asymmetric"),
201            APIStyle::Symmetric => write!(f, "symmetric"),
202        }
203    }
204}
205
206impl FromStr for APIStyle {
207    type Err = anyhow::Error;
208
209    fn from_str(s: &str) -> Result<Self, Self::Err> {
210        match s {
211            "asymmetric" => Ok(APIStyle::Asymmetric),
212            "symmetric" => Ok(APIStyle::Symmetric),
213            _ => bail!("unrecognized API style: `{s}`; expected `asymmetric` or `symmetric`"),
214        }
215    }
216}
217
218#[derive(Default, Debug, Clone, Copy)]
219pub enum Ownership {
220    /// Generated types will be composed entirely of owning fields, regardless
221    /// of whether they are used as parameters to imports or not.
222    #[default]
223    Owning,
224
225    /// Generated types used as parameters to imports will be "deeply
226    /// borrowing", i.e. contain references rather than owned values when
227    /// applicable.
228    CoarseBorrowing,
229
230    /// Generated types used as parameters to imports will be "deeply
231    /// borrowing", i.e. contain references rather than owned values
232    /// for all fields that are not resources, which will be owning.
233    FineBorrowing,
234}
235
236impl FromStr for Ownership {
237    type Err = String;
238
239    fn from_str(s: &str) -> Result<Self, Self::Err> {
240        match s {
241            "owning" => Ok(Self::Owning),
242            "coarse-borrowing" => Ok(Self::CoarseBorrowing),
243            "fine-borrowing" => Ok(Self::FineBorrowing),
244            _ => Err(format!(
245                "unrecognized ownership: `{s}`; \
246                 expected `owning`, `coarse-borrowing`, or `fine-borrowing`"
247            )),
248        }
249    }
250}
251
252impl fmt::Display for Ownership {
253    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
254        f.write_str(match self {
255            Ownership::Owning => "owning",
256            Ownership::CoarseBorrowing => "coarse-borrowing",
257            Ownership::FineBorrowing => "fine-borrowing",
258        })
259    }
260}
261
262impl Opts {
263    pub fn build(mut self, out_dir: Option<&PathBuf>) -> Box<dyn WorldGenerator> {
264        let mut r = Cpp::new();
265        self.out_dir = out_dir.cloned();
266        r.opts = self;
267        Box::new(r)
268    }
269
270    fn is_only_handle(&self, variant: AbiVariant) -> bool {
271        !matches!(variant, AbiVariant::GuestExport)
272    }
273
274    fn ptr_type(&self) -> &'static str {
275        "uint8_t*"
276    }
277}
278
279impl Cpp {
280    fn new() -> Cpp {
281        Cpp::default()
282    }
283
284    pub fn is_first_definition(&mut self, ns: &Vec<String>, name: &str) -> bool {
285        let owned = (ns.to_owned(), name.to_owned());
286        if !self.defined_types.contains(&owned) {
287            self.defined_types.insert(owned);
288            true
289        } else {
290            false
291        }
292    }
293
294    fn include(&mut self, s: &str) {
295        self.includes.push(s.to_string());
296    }
297
298    /// Returns true if the function is a fallible constructor.
299    ///
300    /// Fallible constructors are constructors that return `result<T, E>` instead of just `T`.
301    /// In the generated C++ code, these become static factory methods named `Create` that
302    /// return `std::expected<T, E>`, rather than regular constructors.
303    fn is_fallible_constructor(&self, resolve: &Resolve, func: &Function) -> bool {
304        matches!(&func.kind, FunctionKind::Constructor(_))
305            && func.result.as_ref().is_some_and(|ty| {
306                if let Type::Id(id) = ty {
307                    matches!(&resolve.types[*id].kind, TypeDefKind::Result(_))
308                } else {
309                    false
310                }
311            })
312    }
313
314    fn interface<'a>(
315        &'a mut self,
316        resolve: &'a Resolve,
317        name: Option<&'a WorldKey>,
318        in_guest_import: bool,
319        wasm_import_module: Option<String>,
320    ) -> CppInterfaceGenerator<'a> {
321        let mut sizes = SizeAlign::default();
322        sizes.fill(resolve);
323
324        CppInterfaceGenerator {
325            _src: Source::default(),
326            r#gen: self,
327            resolve,
328            interface: None,
329            _name: name,
330            sizes,
331            in_guest_import,
332            wasm_import_module,
333        }
334    }
335
336    fn clang_format(code: &mut String) {
337        let mut child = Command::new("clang-format")
338            .stdin(Stdio::piped())
339            .stdout(Stdio::piped())
340            .spawn()
341            .expect("failed to spawn `clang-format`");
342        child
343            .stdin
344            .take()
345            .unwrap()
346            .write_all(code.as_bytes())
347            .unwrap();
348        code.truncate(0);
349        child.stdout.take().unwrap().read_to_string(code).unwrap();
350        let status = child.wait().unwrap();
351        assert!(status.success());
352    }
353
354    fn perform_cast(&mut self, op: &str, cast: &Bitcast) -> String {
355        match cast {
356            Bitcast::I32ToF32 | Bitcast::I64ToF32 => {
357                self.dependencies.needs_bit = true;
358                format!("std::bit_cast<float, int32_t>({op})")
359            }
360            Bitcast::F32ToI32 | Bitcast::F32ToI64 => {
361                self.dependencies.needs_bit = true;
362                format!("std::bit_cast<int32_t, float>({op})")
363            }
364            Bitcast::I64ToF64 => {
365                self.dependencies.needs_bit = true;
366                format!("std::bit_cast<double, int64_t>({op})")
367            }
368            Bitcast::F64ToI64 => {
369                self.dependencies.needs_bit = true;
370                format!("std::bit_cast<int64_t, double>({op})")
371            }
372            Bitcast::I32ToI64 | Bitcast::LToI64 | Bitcast::PToP64 => {
373                format!("(int64_t) {op}")
374            }
375            Bitcast::I64ToI32 | Bitcast::PToI32 | Bitcast::LToI32 => {
376                format!("(int32_t) {op}")
377            }
378            Bitcast::P64ToI64 | Bitcast::None | Bitcast::I64ToP64 => op.to_string(),
379            Bitcast::P64ToP | Bitcast::I32ToP | Bitcast::LToP => {
380                format!("(uint8_t*) {op}")
381            }
382            Bitcast::PToL | Bitcast::I32ToL | Bitcast::I64ToL => {
383                format!("(size_t) {op}")
384            }
385            Bitcast::Sequence(sequence) => {
386                let [first, second] = &**sequence;
387                let inner = self.perform_cast(op, first);
388                self.perform_cast(&inner, second)
389            }
390        }
391    }
392
393    fn finish_includes(&mut self) {
394        self.include("<cstdint>");
395        self.include("<utility>"); // for std::move
396        if self.dependencies.needs_string {
397            self.include("<string>");
398        }
399        if self.dependencies.needs_string_view {
400            self.include("<string_view>");
401        }
402        if self.dependencies.needs_vector {
403            self.include("<vector>");
404        }
405        if self.dependencies.needs_expected {
406            self.include("<expected>");
407        }
408        if self.dependencies.needs_optional {
409            self.include("<optional>");
410        }
411        if self.dependencies.needs_cstring {
412            self.include("<cstring>");
413        }
414        if self.dependencies.needs_imported_resources {
415            self.include("<cassert>");
416        }
417        if self.dependencies.needs_exported_resources {
418            self.include("<map>");
419        }
420        if self.dependencies.needs_variant {
421            self.include("<variant>");
422        }
423        if self.dependencies.needs_tuple {
424            self.include("<tuple>");
425        }
426        if self.dependencies.needs_wit {
427            self.include("\"wit.h\"");
428        }
429        if self.dependencies.needs_memory {
430            self.include("<memory>");
431        }
432        if self.dependencies.needs_array {
433            self.include("<array>");
434        }
435        if self.dependencies.needs_bit {
436            self.include("<bit>");
437        }
438    }
439
440    fn start_new_file(&mut self, condition: Option<bool>) -> FileContext {
441        if condition == Some(true) || self.opts.split_interfaces {
442            FileContext {
443                includes: std::mem::take(&mut self.includes),
444                src: std::mem::take(&mut self.h_src),
445                dependencies: std::mem::take(&mut self.dependencies),
446            }
447        } else {
448            Default::default()
449        }
450    }
451
452    fn finish_file(&mut self, namespace: &[String], store: FileContext) {
453        if !store.src.src.is_empty() {
454            let mut header = String::default();
455            self.finish_includes();
456            self.h_src.change_namespace(&[]);
457            uwriteln!(header, "#pragma once");
458            for include in self.includes.iter() {
459                uwriteln!(header, "#include {include}");
460            }
461            header.push_str(&self.h_src.src);
462            let mut filename = namespace.join("-");
463            filename.push_str(".h");
464            if self.opts.format {
465                Self::clang_format(&mut header);
466            }
467            self.user_class_files.insert(filename.clone(), header);
468
469            let _ = std::mem::replace(&mut self.includes, store.includes);
470            let _ = std::mem::replace(&mut self.h_src, store.src);
471            let _ = std::mem::replace(&mut self.dependencies, store.dependencies);
472            self.includes.push(String::from("\"") + &filename + "\"");
473        }
474    }
475}
476
477#[derive(Default)]
478struct FileContext {
479    includes: Vec<String>,
480    src: SourceWithState,
481    dependencies: Includes,
482}
483
484impl WorldGenerator for Cpp {
485    fn preprocess(&mut self, resolve: &Resolve, world: WorldId) {
486        let name = &resolve.worlds[world].name;
487        self.world = name.to_string();
488        self.types.analyze(resolve);
489        self.world_id = Some(world);
490        uwriteln!(
491            self.c_src_head,
492            r#"#include "{}_cpp.h"
493            #include <cstdlib> // realloc
494
495            extern "C" void *cabi_realloc(void *ptr, size_t old_size, size_t align, size_t new_size);
496
497            __attribute__((__weak__, __export_name__("cabi_realloc")))
498            void *cabi_realloc(void *ptr, size_t old_size, size_t align, size_t new_size) {{
499                (void) old_size;
500                if (new_size == 0) return (void*) align;
501                void *ret = realloc(ptr, new_size);
502                if (!ret) abort();
503                return ret;
504            }}
505
506            "#,
507            self.world.to_snake_case(),
508        );
509    }
510
511    fn import_interface(
512        &mut self,
513        resolve: &Resolve,
514        name: &WorldKey,
515        id: InterfaceId,
516        _files: &mut Files,
517    ) -> anyhow::Result<()> {
518        self.imported_interfaces.insert(id);
519
520        let full_name = resolve.name_world_key(name);
521        match self.opts.with.iter().find(|e| e.0 == full_name) {
522            None => {
523                if let Some(prefix) = self
524                    .interface_prefixes
525                    .get(&(Direction::Import, name.clone()))
526                {
527                    self.import_prefix = Some(prefix.clone());
528                }
529
530                let store = self.start_new_file(None);
531                let wasm_import_module = resolve.name_world_key(name);
532                let binding = Some(name);
533                let mut r#gen = self.interface(resolve, binding, true, Some(wasm_import_module));
534                r#gen.interface = Some(id);
535                r#gen.types(id);
536                let namespace =
537                    namespace(resolve, &TypeOwner::Interface(id), false, &r#gen.r#gen.opts);
538
539                for (_name, func) in resolve.interfaces[id].functions.iter() {
540                    if matches!(func.kind, FunctionKind::Freestanding) {
541                        r#gen.r#gen.h_src.change_namespace(&namespace);
542                        r#gen.generate_function(
543                            func,
544                            &TypeOwner::Interface(id),
545                            AbiVariant::GuestImport,
546                        );
547                    }
548                }
549                self.finish_file(&namespace, store);
550            }
551            Some((_, val)) => {
552                let with_quotes = format!("\"{val}\"");
553                if !self.includes.contains(&with_quotes) {
554                    self.includes.push(with_quotes);
555                }
556            }
557        }
558        let _ = self.import_prefix.take();
559        Ok(())
560    }
561
562    fn export_interface(
563        &mut self,
564        resolve: &Resolve,
565        name: &WorldKey,
566        id: InterfaceId,
567        _files: &mut Files,
568    ) -> anyhow::Result<()> {
569        let old_prefix = self.opts.export_prefix.clone();
570        if let Some(prefix) = self
571            .interface_prefixes
572            .get(&(Direction::Export, name.clone()))
573        {
574            self.opts.export_prefix =
575                Some(prefix.clone() + old_prefix.as_ref().unwrap_or(&String::new()));
576        }
577        let store = self.start_new_file(None);
578        self.h_src
579            .src
580            .push_str(&format!("// export_interface {name:?}\n"));
581        self.imported_interfaces.remove(&id);
582        let wasm_import_module = resolve.name_world_key(name);
583        let binding = Some(name);
584        let mut r#gen = self.interface(resolve, binding, false, Some(wasm_import_module));
585        r#gen.interface = Some(id);
586        r#gen.types(id);
587        let namespace = namespace(resolve, &TypeOwner::Interface(id), true, &r#gen.r#gen.opts);
588
589        for (_name, func) in resolve.interfaces[id].functions.iter() {
590            if matches!(func.kind, FunctionKind::Freestanding) {
591                r#gen.r#gen.h_src.change_namespace(&namespace);
592                r#gen.generate_function(func, &TypeOwner::Interface(id), AbiVariant::GuestExport);
593            }
594        }
595        self.finish_file(&namespace, store);
596        self.opts.export_prefix = old_prefix;
597        Ok(())
598    }
599
600    fn import_funcs(
601        &mut self,
602        resolve: &Resolve,
603        world: WorldId,
604        funcs: &[(&str, &Function)],
605        _files: &mut Files,
606    ) {
607        let name = WorldKey::Name("$root".to_string()); //WorldKey::Name(resolve.worlds[world].name.clone());
608        let wasm_import_module = resolve.name_world_key(&name);
609        let binding = Some(name);
610        let mut r#gen = self.interface(resolve, binding.as_ref(), true, Some(wasm_import_module));
611        let namespace = namespace(resolve, &TypeOwner::World(world), false, &r#gen.r#gen.opts);
612
613        for (_name, func) in funcs.iter() {
614            if matches!(func.kind, FunctionKind::Freestanding) {
615                r#gen.r#gen.h_src.change_namespace(&namespace);
616                r#gen.generate_function(func, &TypeOwner::World(world), AbiVariant::GuestImport);
617            }
618        }
619    }
620
621    fn export_funcs(
622        &mut self,
623        resolve: &Resolve,
624        world: WorldId,
625        funcs: &[(&str, &Function)],
626        _files: &mut Files,
627    ) -> anyhow::Result<()> {
628        let name = WorldKey::Name(resolve.worlds[world].name.clone());
629        let binding = Some(name);
630        let mut r#gen = self.interface(resolve, binding.as_ref(), false, None);
631        let namespace = namespace(resolve, &TypeOwner::World(world), true, &r#gen.r#gen.opts);
632
633        for (_name, func) in funcs.iter() {
634            if matches!(func.kind, FunctionKind::Freestanding) {
635                r#gen.r#gen.h_src.change_namespace(&namespace);
636                r#gen.generate_function(func, &TypeOwner::World(world), AbiVariant::GuestExport);
637            }
638        }
639        Ok(())
640    }
641
642    fn import_types(
643        &mut self,
644        resolve: &Resolve,
645        _world: WorldId,
646        types: &[(&str, TypeId)],
647        _files: &mut Files,
648    ) {
649        let mut r#gen = self.interface(resolve, None, true, Some("$root".to_string()));
650        for (name, id) in types.iter() {
651            r#gen.define_type(name, *id);
652        }
653    }
654
655    fn finish(
656        &mut self,
657        resolve: &Resolve,
658        world_id: WorldId,
659        files: &mut Files,
660    ) -> std::result::Result<(), anyhow::Error> {
661        let world = &resolve.worlds[world_id];
662        let snake = world.name.to_snake_case();
663        let linking_symbol = wit_bindgen_c::component_type_object::linking_symbol(&world.name);
664
665        let mut h_str = SourceWithState::default();
666        let mut c_str = SourceWithState::default();
667
668        let version = env!("CARGO_PKG_VERSION");
669        uwriteln!(
670            h_str.src,
671            "// Generated by `wit-bindgen` {version}. DO NOT EDIT!"
672        );
673
674        uwrite!(
675            h_str.src,
676            "#ifndef __CPP_GUEST_BINDINGS_{0}_H
677            #define __CPP_GUEST_BINDINGS_{0}_H\n",
678            world.name.to_shouty_snake_case(),
679        );
680        self.finish_includes();
681
682        for include in self.includes.iter() {
683            uwriteln!(h_str.src, "#include {include}");
684        }
685
686        uwriteln!(
687            c_str.src,
688            "// Generated by `wit-bindgen` {version}. DO NOT EDIT!"
689        );
690        uwriteln!(
691            c_str.src,
692            "\n// Ensure that the *_component_type.o object is linked in"
693        );
694        uwrite!(
695            c_str.src,
696            "#ifdef __wasm32__
697                   extern \"C\" void {linking_symbol}(void);
698                   __attribute__((used))
699                   void {linking_symbol}_public_use_in_this_compilation_unit(void) {{
700                       {linking_symbol}();
701                   }}
702                   #endif
703               ",
704        );
705        if self.dependencies.needs_assert {
706            uwriteln!(c_str.src, "#include <assert.h>");
707        }
708
709        h_str.change_namespace(&Vec::default());
710
711        self.c_src.change_namespace(&Vec::default());
712        c_str.src.push_str(&self.c_src_head);
713        c_str.src.push_str(&self.extern_c_decls);
714        c_str.src.push_str(&self.c_src.src);
715        self.h_src.change_namespace(&Vec::default());
716        h_str.src.push_str(&self.h_src.src);
717
718        uwriteln!(c_str.src, "\n// Component Adapters");
719
720        uwriteln!(
721            h_str.src,
722            "
723            #endif"
724        );
725
726        if self.opts.format {
727            Self::clang_format(c_str.src.as_mut_string());
728            Self::clang_format(h_str.src.as_mut_string());
729        }
730
731        files.push(&format!("{snake}.cpp"), c_str.src.as_bytes());
732        files.push(&format!("{snake}_cpp.h"), h_str.src.as_bytes());
733        for (name, content) in self.user_class_files.iter() {
734            // if the user class file exists create an updated .template
735            let dst = match &self.opts.out_dir {
736                Some(path) => path.join(name),
737                None => name.into(),
738            };
739            if std::path::Path::exists(&dst) {
740                files.push(&(String::from(name) + ".template"), content.as_bytes());
741            } else {
742                files.push(name, content.as_bytes());
743            }
744        }
745        files.push(
746            &format!("{snake}_component_type.o",),
747            wit_bindgen_c::component_type_object::object(
748                resolve,
749                world_id,
750                &world.name,
751                wit_component::StringEncoding::UTF8,
752                None,
753            )
754            .unwrap()
755            .as_slice(),
756        );
757
758        if self.dependencies.needs_wit {
759            files.push("wit.h", include_bytes!("../helper-types/wit.h"));
760        }
761        Ok(())
762    }
763}
764
765// determine namespace (for the lifted C++ function)
766fn namespace(resolve: &Resolve, owner: &TypeOwner, guest_export: bool, opts: &Opts) -> Vec<String> {
767    let mut result = Vec::default();
768    if let Some(prefix) = &opts.internal_prefix {
769        result.push(prefix.clone());
770    }
771    if guest_export {
772        result.push(String::from("exports"));
773    }
774    match owner {
775        TypeOwner::World(w) => result.push(to_c_ident(&resolve.worlds[*w].name)),
776        TypeOwner::Interface(i) => {
777            let iface = &resolve.interfaces[*i];
778            let pkg_id = iface.package.unwrap();
779            let pkg = &resolve.packages[pkg_id];
780            result.push(to_c_ident(&pkg.name.namespace));
781            // Use name_package_module to get version-specific package names
782            result.push(to_c_ident(&name_package_module(resolve, pkg_id)));
783            if let Some(name) = &iface.name {
784                result.push(to_c_ident(name));
785            }
786        }
787        TypeOwner::None => (),
788    }
789    result
790}
791
792impl SourceWithState {
793    fn change_namespace(&mut self, target: &[String]) {
794        let mut same = 0;
795        // itertools::fold_while?
796        for (a, b) in self.namespace.iter().zip(target.iter()) {
797            if a == b {
798                same += 1;
799            } else {
800                break;
801            }
802        }
803        for _i in same..self.namespace.len() {
804            uwrite!(self.src, "}}\n");
805        }
806        self.namespace.truncate(same);
807        for i in target.iter().skip(same) {
808            uwrite!(self.src, "namespace {} {{\n", i);
809            self.namespace.push(i.clone());
810        }
811    }
812
813    fn qualify(&mut self, target: &[String]) {
814        let mut same = 0;
815        // itertools::fold_while?
816        for (a, b) in self.namespace.iter().zip(target.iter()) {
817            if a == b {
818                same += 1;
819            } else {
820                break;
821            }
822        }
823        if same == 0 && !target.is_empty() {
824            // if the root namespace exists below the current namespace we need to start at root
825            // Also ensure absolute qualification when crossing from exports to imports
826            if self.namespace.contains(target.first().unwrap())
827                || (self.namespace.first().map(|s| s.as_str()) == Some("exports")
828                    && target.first().map(|s| s.as_str()) != Some("exports"))
829            {
830                self.src.push_str("::");
831            }
832        }
833        if same == target.len() && self.namespace.len() != target.len() && same > 0 {
834            // namespace is parent, qualify at least one namespace (and cross fingers)
835            uwrite!(self.src, "{}::", target[same - 1]);
836        } else {
837            for i in target.iter().skip(same) {
838                uwrite!(self.src, "{i}::");
839            }
840        }
841    }
842}
843
844struct CppInterfaceGenerator<'a> {
845    _src: Source,
846    r#gen: &'a mut Cpp,
847    resolve: &'a Resolve,
848    interface: Option<InterfaceId>,
849    _name: Option<&'a WorldKey>,
850    sizes: SizeAlign,
851    in_guest_import: bool,
852    pub wasm_import_module: Option<String>,
853}
854
855impl CppInterfaceGenerator<'_> {
856    fn types(&mut self, iface: InterfaceId) {
857        let iface_data = &self.resolve().interfaces[iface];
858
859        // First pass: emit forward declarations for all resources
860        // This ensures resources can reference each other in method signatures
861        for (name, id) in iface_data.types.iter() {
862            let ty = &self.resolve().types[*id];
863            if matches!(&ty.kind, TypeDefKind::Resource) {
864                let pascal = name.to_upper_camel_case();
865                let guest_import = self.r#gen.imported_interfaces.contains(&iface);
866                let namespc = namespace(self.resolve, &ty.owner, !guest_import, &self.r#gen.opts);
867                self.r#gen.h_src.change_namespace(&namespc);
868                uwriteln!(self.r#gen.h_src.src, "class {pascal};");
869            }
870        }
871
872        // Second pass: emit full type definitions
873        for (name, id) in iface_data.types.iter() {
874            self.define_type(name, *id);
875        }
876    }
877
878    fn define_type(&mut self, name: &str, id: TypeId) {
879        let ty = &self.resolve().types[id];
880        match &ty.kind {
881            TypeDefKind::Record(record) => self.type_record(id, name, record, &ty.docs),
882            TypeDefKind::Resource => self.type_resource(id, name, &ty.docs),
883            TypeDefKind::Flags(flags) => self.type_flags(id, name, flags, &ty.docs),
884            TypeDefKind::Tuple(tuple) => self.type_tuple(id, name, tuple, &ty.docs),
885            TypeDefKind::Enum(enum_) => self.type_enum(id, name, enum_, &ty.docs),
886            TypeDefKind::Variant(variant) => self.type_variant(id, name, variant, &ty.docs),
887            TypeDefKind::Option(t) => self.type_option(id, name, t, &ty.docs),
888            TypeDefKind::Result(r) => self.type_result(id, name, r, &ty.docs),
889            TypeDefKind::List(t) => self.type_list(id, name, t, &ty.docs),
890            TypeDefKind::Type(t) => self.type_alias(id, name, t, &ty.docs),
891            TypeDefKind::Future(_) => todo!("generate for future"),
892            TypeDefKind::Stream(_) => todo!("generate for stream"),
893            TypeDefKind::Handle(_) => todo!("generate for handle"),
894            TypeDefKind::FixedSizeList(_, _) => todo!(),
895            TypeDefKind::Map(_, _) => todo!(),
896            TypeDefKind::Unknown => unreachable!(),
897        }
898    }
899
900    /// This describes the C++ side name
901    fn func_namespace_name(
902        &self,
903        func: &Function,
904        guest_export: bool,
905        cpp_file: bool,
906    ) -> (Vec<String>, String) {
907        let (object, owner) = match &func.kind {
908            FunctionKind::Freestanding => None,
909            FunctionKind::Method(i) => Some(i),
910            FunctionKind::Static(i) => Some(i),
911            FunctionKind::Constructor(i) => Some(i),
912            FunctionKind::AsyncFreestanding => todo!(),
913            FunctionKind::AsyncMethod(_id) => todo!(),
914            FunctionKind::AsyncStatic(_id) => todo!(),
915        }
916        .map(|i| {
917            let ty = &self.resolve.types[*i];
918            (ty.name.as_ref().unwrap().to_pascal_case(), ty.owner)
919        })
920        .unwrap_or((
921            Default::default(),
922            self.interface
923                .map(TypeOwner::Interface)
924                .unwrap_or(TypeOwner::World(self.r#gen.world_id.unwrap())),
925        ));
926        let mut namespace = namespace(self.resolve, &owner, guest_export, &self.r#gen.opts);
927        let is_drop = is_special_method(func);
928        let func_name_h = if !matches!(&func.kind, FunctionKind::Freestanding) {
929            namespace.push(object.clone());
930            if let FunctionKind::Constructor(_i) = &func.kind {
931                // Fallible constructors return result<T, E> and are static factory methods
932                let is_fallible_constructor =
933                    self.r#gen.is_fallible_constructor(self.resolve, func);
934
935                if is_fallible_constructor {
936                    String::from("Create")
937                } else if guest_export && cpp_file {
938                    String::from("New")
939                } else {
940                    object.clone()
941                }
942            } else {
943                match is_drop {
944                    SpecialMethod::ResourceDrop => {
945                        if guest_export {
946                            "ResourceDrop".to_string()
947                        } else {
948                            "~".to_string() + &object
949                        }
950                    }
951                    SpecialMethod::Dtor => "Dtor".to_string(),
952                    SpecialMethod::ResourceNew => "ResourceNew".to_string(),
953                    SpecialMethod::ResourceRep => "ResourceRep".to_string(),
954                    SpecialMethod::Allocate => "New".to_string(),
955                    SpecialMethod::None => func.item_name().to_pascal_case(),
956                }
957            }
958        } else {
959            func.name.to_pascal_case()
960        };
961        (namespace, func_name_h)
962    }
963
964    // print the signature of the guest export (lowered (wasm) function calling into highlevel)
965    fn print_export_signature(&mut self, func: &Function, variant: AbiVariant) -> Vec<String> {
966        let is_drop = is_special_method(func);
967        let id_type = WasmType::I32;
968        let signature = match is_drop {
969            SpecialMethod::ResourceDrop => WasmSignature {
970                params: vec![id_type],
971                results: Vec::new(),
972                indirect_params: false,
973                retptr: false,
974            },
975            SpecialMethod::ResourceRep => WasmSignature {
976                params: vec![id_type],
977                results: vec![WasmType::Pointer],
978                indirect_params: false,
979                retptr: false,
980            },
981            SpecialMethod::Dtor => WasmSignature {
982                params: vec![WasmType::Pointer],
983                results: Vec::new(),
984                indirect_params: false,
985                retptr: false,
986            },
987            SpecialMethod::ResourceNew => WasmSignature {
988                params: vec![WasmType::Pointer],
989                results: vec![id_type],
990                indirect_params: false,
991                retptr: false,
992            },
993            SpecialMethod::None => {
994                // TODO perhaps remember better names for the arguments
995                self.resolve.wasm_signature(variant, func)
996            }
997            SpecialMethod::Allocate => WasmSignature {
998                params: vec![],
999                results: vec![],
1000                indirect_params: false,
1001                retptr: false,
1002            },
1003        };
1004        let mut module_name = self.wasm_import_module.clone();
1005        let symbol_variant = variant;
1006        if matches!(variant, AbiVariant::GuestExport)
1007            && matches!(
1008                is_drop,
1009                SpecialMethod::ResourceNew
1010                    | SpecialMethod::ResourceDrop
1011                    | SpecialMethod::ResourceRep
1012            )
1013        {
1014            module_name = Some(String::from("[export]") + &module_name.unwrap());
1015        }
1016        let func_name = func.name.clone();
1017        let module_prefix = module_name.as_ref().map_or(String::default(), |name| {
1018            let mut res = name.clone();
1019            res.push('#');
1020            res
1021        });
1022        uwriteln!(
1023            self.r#gen.c_src.src,
1024            r#"extern "C" __attribute__((__export_name__("{module_prefix}{func_name}")))"#
1025        );
1026        let return_via_pointer = false;
1027        self.r#gen
1028            .c_src
1029            .src
1030            .push_str(if signature.results.is_empty() || return_via_pointer {
1031                "void"
1032            } else {
1033                wit_bindgen_c::wasm_type(signature.results[0])
1034            });
1035        self.r#gen.c_src.src.push_str(" ");
1036        let export_name = match module_name {
1037            Some(ref module_name) => make_external_symbol(module_name, &func_name, symbol_variant),
1038            None => make_external_component(&func_name),
1039        };
1040        // Add prefix to C ABI export functions to avoid conflicts with C++ namespaces
1041        self.r#gen.c_src.src.push_str("__wasm_export_");
1042        if let Some(prefix) = self.r#gen.opts.export_prefix.as_ref() {
1043            self.r#gen.c_src.src.push_str(prefix);
1044        }
1045        self.r#gen.c_src.src.push_str(&export_name);
1046        self.r#gen.c_src.src.push_str("(");
1047        let mut first_arg = true;
1048        let mut params = Vec::new();
1049        for (n, ty) in signature.params.iter().enumerate() {
1050            let name = format!("arg{n}");
1051            if !first_arg {
1052                self.r#gen.c_src.src.push_str(", ");
1053            } else {
1054                first_arg = false;
1055            }
1056            self.r#gen.c_src.src.push_str(wit_bindgen_c::wasm_type(*ty));
1057            self.r#gen.c_src.src.push_str(" ");
1058            self.r#gen.c_src.src.push_str(&name);
1059            params.push(name);
1060        }
1061        if return_via_pointer {
1062            if !first_arg {
1063                self.r#gen.c_src.src.push_str(", ");
1064            }
1065            self.r#gen.c_src.src.push_str(self.r#gen.opts.ptr_type());
1066            self.r#gen.c_src.src.push_str(" resultptr");
1067            params.push("resultptr".into());
1068        }
1069        self.r#gen.c_src.src.push_str(")\n");
1070        params
1071    }
1072
1073    fn high_level_signature(
1074        &mut self,
1075        func: &Function,
1076        abi_variant: AbiVariant,
1077        outer_namespace: &[String],
1078    ) -> HighlevelSignature {
1079        let mut res = HighlevelSignature::default();
1080
1081        let (namespace, func_name_h) =
1082            self.func_namespace_name(func, matches!(abi_variant, AbiVariant::GuestExport), false);
1083        res.name = func_name_h;
1084        res.namespace = namespace;
1085        let is_drop = is_special_method(func);
1086        // we might want to separate c_sig and h_sig
1087        // let mut sig = String::new();
1088
1089        // Check if this is a fallible constructor (returns result<T, E>)
1090        let is_fallible_constructor = self.r#gen.is_fallible_constructor(self.resolve, func);
1091
1092        // not for ctor nor imported dtor on guest (except fallible constructors)
1093        if (!matches!(&func.kind, FunctionKind::Constructor(_)) || is_fallible_constructor)
1094            && !(matches!(is_drop, SpecialMethod::ResourceDrop)
1095                && matches!(abi_variant, AbiVariant::GuestImport))
1096        {
1097            if matches!(is_drop, SpecialMethod::Allocate) {
1098                res.result.push_str("Owned");
1099            } else if let Some(ty) = &func.result {
1100                res.result.push_str(
1101                    &(self.type_name(ty, outer_namespace, Flavor::Result(abi_variant))
1102                        + if matches!(is_drop, SpecialMethod::ResourceRep) {
1103                            "*"
1104                        } else {
1105                            ""
1106                        }),
1107                );
1108            } else {
1109                res.result = "void".into();
1110            }
1111            if matches!(abi_variant, AbiVariant::GuestExport)
1112                && abi::guest_export_needs_post_return(self.resolve, func)
1113            {
1114                res.post_return = true;
1115            }
1116        }
1117        if (matches!(func.kind, FunctionKind::Static(_)) || is_fallible_constructor)
1118            && !(matches!(&is_drop, SpecialMethod::ResourceDrop)
1119                && matches!(abi_variant, AbiVariant::GuestImport))
1120        {
1121            res.static_member = true;
1122        }
1123        for (i, (name, param)) in func.params.iter().enumerate() {
1124            if i == 0
1125                && name == "self"
1126                && (matches!(&func.kind, FunctionKind::Method(_))
1127                    || (matches!(&is_drop, SpecialMethod::ResourceDrop)
1128                        && matches!(abi_variant, AbiVariant::GuestImport)))
1129            {
1130                res.implicit_self = true;
1131                continue;
1132            }
1133            let is_pointer = if i == 0
1134                && name == "self"
1135                && matches!(&is_drop, SpecialMethod::Dtor | SpecialMethod::ResourceNew)
1136                && matches!(abi_variant, AbiVariant::GuestExport)
1137            {
1138                "*"
1139            } else {
1140                ""
1141            };
1142            res.arguments.push((
1143                to_c_ident(name),
1144                self.type_name(param, &res.namespace, Flavor::Argument(abi_variant)) + is_pointer,
1145            ));
1146        }
1147        // default to non-const when exporting a method
1148        let import = matches!(abi_variant, AbiVariant::GuestImport);
1149        if matches!(func.kind, FunctionKind::Method(_)) && import {
1150            res.const_member = true;
1151        }
1152        res
1153    }
1154
1155    fn print_signature(
1156        &mut self,
1157        func: &Function,
1158        variant: AbiVariant,
1159        import: bool,
1160    ) -> Vec<String> {
1161        let is_special = is_special_method(func);
1162        let from_namespace = self.r#gen.h_src.namespace.clone();
1163        let cpp_sig = self.high_level_signature(func, variant, &from_namespace);
1164        if cpp_sig.static_member {
1165            self.r#gen.h_src.src.push_str("static ");
1166        }
1167        self.r#gen.h_src.src.push_str(&cpp_sig.result);
1168        if !cpp_sig.result.is_empty() {
1169            self.r#gen.h_src.src.push_str(" ");
1170        }
1171        self.r#gen.h_src.src.push_str(&cpp_sig.name);
1172        self.r#gen.h_src.src.push_str("(");
1173        for (num, (arg, typ)) in cpp_sig.arguments.iter().enumerate() {
1174            if num > 0 {
1175                self.r#gen.h_src.src.push_str(", ");
1176            }
1177            self.r#gen.h_src.src.push_str(typ);
1178            self.r#gen.h_src.src.push_str(" ");
1179            self.r#gen.h_src.src.push_str(arg);
1180        }
1181        self.r#gen.h_src.src.push_str(")");
1182        if cpp_sig.const_member {
1183            self.r#gen.h_src.src.push_str(" const");
1184        }
1185        match (&is_special, false, &variant) {
1186            (SpecialMethod::Allocate, _, _) => {
1187                uwriteln!(
1188                    self.r#gen.h_src.src,
1189                    "{{\
1190                        return {OWNED_CLASS_NAME}(new {}({}));\
1191                    }}",
1192                    cpp_sig.namespace.last().unwrap(), //join("::"),
1193                    cpp_sig
1194                        .arguments
1195                        .iter()
1196                        .map(|(arg, _)| format!("std::move({arg})"))
1197                        .collect::<Vec<_>>()
1198                        .join(", ")
1199                );
1200                // body is inside the header
1201                return Vec::default();
1202            }
1203            (SpecialMethod::Dtor, _, _ /*AbiVariant::GuestImport*/)
1204            | (SpecialMethod::ResourceDrop, true, _) => {
1205                uwriteln!(
1206                    self.r#gen.h_src.src,
1207                    "{{\
1208                        delete {};\
1209                    }}",
1210                    cpp_sig.arguments.first().unwrap().0
1211                );
1212            }
1213            _ => self.r#gen.h_src.src.push_str(";\n"),
1214        }
1215
1216        // we want to separate the lowered signature (wasm) and the high level signature
1217        if !import
1218            && !matches!(
1219                &is_special,
1220                SpecialMethod::ResourceDrop
1221                    | SpecialMethod::ResourceNew
1222                    | SpecialMethod::ResourceRep
1223            )
1224        {
1225            self.print_export_signature(func, variant)
1226        } else {
1227            // recalulate with c file namespace
1228            let c_namespace = self.r#gen.c_src.namespace.clone();
1229            let cpp_sig = self.high_level_signature(func, variant, &c_namespace);
1230            let mut params = Vec::new();
1231            self.r#gen.c_src.src.push_str(&cpp_sig.result);
1232            if !cpp_sig.result.is_empty() {
1233                self.r#gen.c_src.src.push_str(" ");
1234            }
1235            self.r#gen.c_src.qualify(&cpp_sig.namespace);
1236            self.r#gen.c_src.src.push_str(&cpp_sig.name);
1237            self.r#gen.c_src.src.push_str("(");
1238            if cpp_sig.implicit_self {
1239                params.push("(*this)".into());
1240            }
1241            for (num, (arg, typ)) in cpp_sig.arguments.iter().enumerate() {
1242                if num > 0 {
1243                    self.r#gen.c_src.src.push_str(", ");
1244                }
1245                self.r#gen.c_src.src.push_str(typ);
1246                self.r#gen.c_src.src.push_str(" ");
1247                self.r#gen.c_src.src.push_str(arg);
1248                params.push(arg.clone());
1249            }
1250            self.r#gen.c_src.src.push_str(")");
1251            if cpp_sig.const_member {
1252                self.r#gen.c_src.src.push_str(" const");
1253            }
1254            self.r#gen.c_src.src.push_str("\n");
1255            params
1256        }
1257    }
1258
1259    fn generate_function(&mut self, func: &Function, owner: &TypeOwner, variant: AbiVariant) {
1260        fn class_namespace(
1261            cifg: &CppInterfaceGenerator,
1262            func: &Function,
1263            variant: AbiVariant,
1264        ) -> Vec<String> {
1265            let owner = &cifg.resolve.types[match &func.kind {
1266                FunctionKind::Static(id) => *id,
1267                _ => panic!("special func should be static"),
1268            }];
1269            let mut namespace = namespace(
1270                cifg.resolve,
1271                &owner.owner,
1272                matches!(variant, AbiVariant::GuestExport),
1273                &cifg.r#gen.opts,
1274            );
1275            namespace.push(owner.name.as_ref().unwrap().to_upper_camel_case());
1276            namespace
1277        }
1278
1279        let export = match variant {
1280            AbiVariant::GuestImport => false,
1281            AbiVariant::GuestExport => true,
1282            AbiVariant::GuestImportAsync => todo!(),
1283            AbiVariant::GuestExportAsync => todo!(),
1284            AbiVariant::GuestExportAsyncStackful => todo!(),
1285        };
1286        let params = self.print_signature(func, variant, !export);
1287        let special = is_special_method(func);
1288        if !matches!(special, SpecialMethod::Allocate) {
1289            self.r#gen.c_src.src.push_str("{\n");
1290            let needs_dealloc = if self.r#gen.opts.api_style == APIStyle::Symmetric
1291                && matches!(variant, AbiVariant::GuestExport)
1292            {
1293                self.r#gen
1294                    .c_src
1295                    .src
1296                    .push_str("std::vector<void*> _deallocate;\n");
1297                self.r#gen.dependencies.needs_vector = true;
1298                true
1299            } else {
1300                false
1301            };
1302            let lift_lower = if export {
1303                LiftLower::LiftArgsLowerResults
1304            } else {
1305                LiftLower::LowerArgsLiftResults
1306            };
1307            match is_special_method(func) {
1308                SpecialMethod::ResourceDrop => match lift_lower {
1309                    LiftLower::LiftArgsLowerResults => {
1310                        let module_name =
1311                            String::from("[export]") + &self.wasm_import_module.clone().unwrap();
1312                        let wasm_sig =
1313                            self.declare_import(&module_name, &func.name, &[WasmType::I32], &[]);
1314                        uwriteln!(
1315                            self.r#gen.c_src.src,
1316                            "{wasm_sig}({});",
1317                            func.params.first().unwrap().0
1318                        );
1319                    }
1320                    LiftLower::LowerArgsLiftResults => {
1321                        let module_name = self.wasm_import_module.clone().unwrap();
1322                        let name =
1323                            self.declare_import(&module_name, &func.name, &[WasmType::I32], &[]);
1324                        uwriteln!(
1325                            self.r#gen.c_src.src,
1326                            "   if (handle>=0) {{
1327                                {name}(handle);
1328                            }}"
1329                        );
1330                    }
1331                },
1332                SpecialMethod::Dtor => {
1333                    let classname = class_namespace(self, func, variant).join("::");
1334                    uwriteln!(self.r#gen.c_src.src, "(({classname}*)arg0)->handle=-1;");
1335                    uwriteln!(self.r#gen.c_src.src, "{0}::Dtor(({0}*)arg0);", classname);
1336                }
1337                SpecialMethod::ResourceNew => {
1338                    let module_name =
1339                        String::from("[export]") + &self.wasm_import_module.clone().unwrap();
1340                    let wasm_sig = self.declare_import(
1341                        &module_name,
1342                        &func.name,
1343                        &[WasmType::Pointer],
1344                        &[WasmType::I32],
1345                    );
1346                    uwriteln!(
1347                        self.r#gen.c_src.src,
1348                        "return {wasm_sig}(({}){});",
1349                        self.r#gen.opts.ptr_type(),
1350                        func.params.first().unwrap().0
1351                    );
1352                }
1353                SpecialMethod::ResourceRep => {
1354                    let module_name =
1355                        String::from("[export]") + &self.wasm_import_module.clone().unwrap();
1356                    let wasm_sig = self.declare_import(
1357                        &module_name,
1358                        &func.name,
1359                        &[WasmType::I32],
1360                        &[WasmType::Pointer],
1361                    );
1362                    let classname = class_namespace(self, func, variant).join("::");
1363                    uwriteln!(
1364                        self.r#gen.c_src.src,
1365                        "return ({}*){wasm_sig}({});",
1366                        classname,
1367                        func.params.first().unwrap().0
1368                    );
1369                }
1370                SpecialMethod::Allocate => unreachable!(),
1371                SpecialMethod::None => {
1372                    // normal methods
1373                    let namespace = if matches!(func.kind, FunctionKind::Freestanding) {
1374                        namespace(
1375                            self.resolve,
1376                            owner,
1377                            matches!(variant, AbiVariant::GuestExport),
1378                            &self.r#gen.opts,
1379                        )
1380                    } else {
1381                        let owner = &self.resolve.types[match &func.kind {
1382                            FunctionKind::Static(id) => *id,
1383                            FunctionKind::Constructor(id) => *id,
1384                            FunctionKind::Method(id) => *id,
1385                            FunctionKind::Freestanding => unreachable!(),
1386                            FunctionKind::AsyncFreestanding => todo!(),
1387                            FunctionKind::AsyncMethod(_id) => todo!(),
1388                            FunctionKind::AsyncStatic(_id) => todo!(),
1389                        }]
1390                        .clone();
1391                        let mut namespace = namespace(
1392                            self.resolve,
1393                            &owner.owner,
1394                            matches!(variant, AbiVariant::GuestExport),
1395                            &self.r#gen.opts,
1396                        );
1397                        namespace.push(owner.name.as_ref().unwrap().to_upper_camel_case());
1398                        namespace
1399                    };
1400                    let mut f = FunctionBindgen::new(self, params);
1401                    if !export {
1402                        f.namespace = namespace.clone();
1403                    }
1404                    f.variant = variant;
1405                    f.needs_dealloc = needs_dealloc;
1406                    f.cabi_post = None;
1407                    abi::call(f.r#gen.resolve, variant, lift_lower, func, &mut f, false);
1408                    let ret_area_decl = f.emit_ret_area_if_needed();
1409                    let code = format!("{}{}", ret_area_decl, String::from(f.src));
1410                    self.r#gen.c_src.src.push_str(&code);
1411                }
1412            }
1413            self.r#gen.c_src.src.push_str("}\n");
1414            // cabi_post
1415            if matches!(variant, AbiVariant::GuestExport)
1416                && abi::guest_export_needs_post_return(self.resolve, func)
1417            {
1418                let sig = self.resolve.wasm_signature(variant, func);
1419                let module_name = self.wasm_import_module.clone();
1420                let export_name = match module_name {
1421                    Some(ref module_name) => {
1422                        format!("{module_name}#{}", func.name)
1423                    }
1424                    None => make_external_component(&func.name),
1425                };
1426                let import_name = match module_name {
1427                    Some(ref module_name) => {
1428                        make_external_symbol(module_name, &func.name, AbiVariant::GuestExport)
1429                    }
1430                    None => make_external_component(&func.name),
1431                };
1432                uwriteln!(
1433                    self.r#gen.c_src.src,
1434                    "extern \"C\" __attribute__((__weak__, __export_name__(\"cabi_post_{export_name}\")))"
1435                );
1436                uwrite!(self.r#gen.c_src.src, "void cabi_post_{import_name}(");
1437
1438                let mut params = Vec::new();
1439                for (i, result) in sig.results.iter().enumerate() {
1440                    let name = format!("arg{i}");
1441                    uwrite!(
1442                        self.r#gen.c_src.src,
1443                        "{} {name}",
1444                        wit_bindgen_c::wasm_type(*result)
1445                    );
1446                    params.push(name);
1447                }
1448                self.r#gen.c_src.src.push_str(") {\n");
1449
1450                let mut f = FunctionBindgen::new(self, params.clone());
1451                f.params = params;
1452                abi::post_return(f.r#gen.resolve, func, &mut f);
1453                let ret_area_decl = f.emit_ret_area_if_needed();
1454                let code = format!("{}{}", ret_area_decl, String::from(f.src));
1455                self.r#gen.c_src.src.push_str(&code);
1456                self.r#gen.c_src.src.push_str("}\n");
1457            }
1458        }
1459    }
1460
1461    // in C this is print_optional_ty
1462    fn optional_type_name(
1463        &mut self,
1464        ty: Option<&Type>,
1465        from_namespace: &[String],
1466        flavor: Flavor,
1467    ) -> String {
1468        match ty {
1469            Some(ty) => self.type_name(ty, from_namespace, flavor),
1470            None => "void".into(),
1471        }
1472    }
1473
1474    fn scoped_record_name(
1475        &self,
1476        id: TypeId,
1477        from_namespace: &[String],
1478        guest_export: bool,
1479        flavor: Flavor,
1480    ) -> String {
1481        let name = self.scoped_type_name(id, from_namespace, guest_export);
1482
1483        if let Flavor::Argument(AbiVariant::GuestImport) = flavor {
1484            match self.r#gen.opts.ownership {
1485                Ownership::Owning => name.to_string(),
1486                Ownership::CoarseBorrowing => {
1487                    if self.r#gen.types.get(id).has_own_handle {
1488                        name.to_string()
1489                    } else {
1490                        format!("{name}Param")
1491                    }
1492                }
1493                Ownership::FineBorrowing => {
1494                    format!("{name}Param")
1495                }
1496            }
1497        } else {
1498            name
1499        }
1500    }
1501
1502    fn scoped_type_name(
1503        &self,
1504        id: TypeId,
1505        from_namespace: &[String],
1506        guest_export: bool,
1507    ) -> String {
1508        let ty = &self.resolve.types[id];
1509        let namespc = namespace(self.resolve, &ty.owner, guest_export, &self.r#gen.opts);
1510        let mut relative = SourceWithState {
1511            namespace: Vec::from(from_namespace),
1512            ..Default::default()
1513        };
1514        relative.qualify(&namespc);
1515        format!(
1516            "{}{}",
1517            &*relative.src,
1518            ty.name.as_ref().unwrap().to_pascal_case()
1519        )
1520    }
1521
1522    fn type_name(&mut self, ty: &Type, from_namespace: &[String], flavor: Flavor) -> String {
1523        match ty {
1524            Type::Bool => "bool".into(),
1525            Type::Char => "uint32_t".into(),
1526            Type::U8 => "uint8_t".into(),
1527            Type::S8 => "int8_t".into(),
1528            Type::U16 => "uint16_t".into(),
1529            Type::S16 => "int16_t".into(),
1530            Type::U32 => "uint32_t".into(),
1531            Type::S32 => "int32_t".into(),
1532            Type::U64 => "uint64_t".into(),
1533            Type::S64 => "int64_t".into(),
1534            Type::F32 => "float".into(),
1535            Type::F64 => "double".into(),
1536            Type::String => match flavor {
1537                Flavor::BorrowedArgument => {
1538                    self.r#gen.dependencies.needs_string_view = true;
1539                    "std::string_view".into()
1540                }
1541                Flavor::Argument(var)
1542                    if matches!(var, AbiVariant::GuestImport)
1543                        || self.r#gen.opts.api_style == APIStyle::Symmetric =>
1544                {
1545                    self.r#gen.dependencies.needs_string_view = true;
1546                    "std::string_view".into()
1547                }
1548                Flavor::Argument(AbiVariant::GuestExport) => {
1549                    self.r#gen.dependencies.needs_wit = true;
1550                    "wit::string".into()
1551                }
1552                _ => {
1553                    self.r#gen.dependencies.needs_wit = true;
1554                    "wit::string".into()
1555                }
1556            },
1557            Type::Id(id) => match &self.resolve.types[*id].kind {
1558                TypeDefKind::Record(_) => {
1559                    let guest_export = self.is_exported_type(&self.resolve.types[*id]);
1560                    self.scoped_record_name(*id, from_namespace, guest_export, flavor)
1561                }
1562                TypeDefKind::Resource => {
1563                    let guest_export = self.is_exported_type(&self.resolve.types[*id]);
1564                    self.scoped_type_name(*id, from_namespace, guest_export)
1565                }
1566                TypeDefKind::Handle(Handle::Own(id)) => {
1567                    let mut typename = self.type_name(&Type::Id(*id), from_namespace, flavor);
1568                    let ty = &self.resolve.types[*id];
1569
1570                    // Follow type aliases to find the actual resource definition
1571                    // When a resource is `use`d in another interface, we have a type alias
1572                    // with the new interface as owner. We need to follow to the original resource.
1573                    let resource_ty = match &ty.kind {
1574                        TypeDefKind::Type(Type::Id(resource_id)) => {
1575                            &self.resolve.types[*resource_id]
1576                        }
1577                        _ => ty,
1578                    };
1579
1580                    let is_exported = self.is_exported_type(resource_ty);
1581                    match (false, flavor) {
1582                        (false, Flavor::Argument(AbiVariant::GuestImport))
1583                        | (true, Flavor::Argument(AbiVariant::GuestExport)) => {
1584                            typename.push_str("&&")
1585                        }
1586                        (false, Flavor::Argument(AbiVariant::GuestExport))
1587                        | (false, Flavor::Result(AbiVariant::GuestExport))
1588                        | (true, Flavor::Argument(AbiVariant::GuestImport))
1589                        | (true, Flavor::Result(AbiVariant::GuestImport)) => {
1590                            // Only exported resources have ::Owned typedef
1591                            if is_exported {
1592                                typename.push_str(&format!("::{OWNED_CLASS_NAME}"))
1593                            } else {
1594                                typename.push_str("&&")
1595                            }
1596                        }
1597                        (false, Flavor::Result(AbiVariant::GuestImport))
1598                        | (true, Flavor::Result(AbiVariant::GuestExport)) => (),
1599                        (_, Flavor::InStruct) => (),
1600                        (false, Flavor::BorrowedArgument) => (),
1601                        (_, _) => todo!(),
1602                    }
1603                    if matches!(flavor, Flavor::InStruct) && is_exported {
1604                        typename.push_str(&format!("::{OWNED_CLASS_NAME}"))
1605                    }
1606                    typename
1607                }
1608                TypeDefKind::Handle(Handle::Borrow(id)) => {
1609                    "std::reference_wrapper<const ".to_string()
1610                        + &self.type_name(&Type::Id(*id), from_namespace, flavor)
1611                        + ">"
1612                }
1613                TypeDefKind::Flags(_f) => {
1614                    let ty = &self.resolve.types[*id];
1615                    let guest_export = self.is_exported_type(ty);
1616                    self.scoped_type_name(*id, from_namespace, guest_export)
1617                }
1618                TypeDefKind::Tuple(t) => {
1619                    let types = t.types.iter().fold(String::new(), |mut a, b| {
1620                        if !a.is_empty() {
1621                            a += ", ";
1622                        }
1623                        a + &self.type_name(b, from_namespace, flavor)
1624                    });
1625                    self.r#gen.dependencies.needs_tuple = true;
1626                    String::from("std::tuple<") + &types + ">"
1627                }
1628                TypeDefKind::Variant(_v) => {
1629                    let ty = &self.resolve.types[*id];
1630                    let guest_export = self.is_exported_type(ty);
1631                    self.scoped_type_name(*id, from_namespace, guest_export)
1632                }
1633                TypeDefKind::Enum(_e) => {
1634                    let ty = &self.resolve.types[*id];
1635                    let guest_export = self.is_exported_type(ty);
1636                    self.scoped_type_name(*id, from_namespace, guest_export)
1637                }
1638                TypeDefKind::Option(o) => {
1639                    // Template parameters need base types without && or other decorations
1640                    // For import arguments, use BorrowedArgument flavor to get string_view
1641                    let template_flavor = match flavor {
1642                        Flavor::Argument(AbiVariant::GuestImport) => Flavor::BorrowedArgument,
1643                        _ => Flavor::InStruct,
1644                    };
1645                    self.r#gen.dependencies.needs_optional = true;
1646                    "std::optional<".to_string()
1647                        + &self.type_name(o, from_namespace, template_flavor)
1648                        + ">"
1649                }
1650                TypeDefKind::Result(r) => {
1651                    // Template parameters need base types without && or other decorations
1652                    let template_flavor = Flavor::InStruct;
1653                    let err_type = r.err.as_ref().map_or(String::from("wit::Void"), |ty| {
1654                        self.type_name(ty, from_namespace, template_flavor)
1655                    });
1656                    self.r#gen.dependencies.needs_expected = true;
1657                    "std::expected<".to_string()
1658                        + &self.optional_type_name(r.ok.as_ref(), from_namespace, template_flavor)
1659                        + ", "
1660                        + &err_type
1661                        + ">"
1662                }
1663                TypeDefKind::List(ty) => {
1664                    // For list elements, use BorrowedArgument flavor for imported functions
1665                    // to get std::string_view instead of wit::string. Otherwise use InStruct
1666                    // flavor to avoid adding && to owned resources (lists contain values, not rvalue references)
1667                    let element_flavor = match flavor {
1668                        Flavor::BorrowedArgument | Flavor::Argument(AbiVariant::GuestImport) => {
1669                            Flavor::BorrowedArgument
1670                        }
1671                        _ => Flavor::InStruct,
1672                    };
1673                    let inner = self.type_name(ty, from_namespace, element_flavor);
1674                    match flavor {
1675                        Flavor::BorrowedArgument => {
1676                            self.r#gen.dependencies.needs_span = true;
1677                            format!("std::span<{inner} const>")
1678                        }
1679                        Flavor::Argument(var)
1680                            if matches!(var, AbiVariant::GuestImport)
1681                                || self.r#gen.opts.api_style == APIStyle::Symmetric =>
1682                        {
1683                            self.r#gen.dependencies.needs_span = true;
1684                            // If the list has an owning handle, it must support moving, so can't be const
1685                            let constness = if self.r#gen.types.get(*id).has_own_handle {
1686                                ""
1687                            } else {
1688                                " const"
1689                            };
1690                            format!("std::span<{inner}{constness}>")
1691                        }
1692                        Flavor::Argument(AbiVariant::GuestExport) => {
1693                            self.r#gen.dependencies.needs_wit = true;
1694                            format!("wit::vector<{inner}>")
1695                        }
1696                        _ => {
1697                            self.r#gen.dependencies.needs_wit = true;
1698                            format!("wit::vector<{inner}>")
1699                        }
1700                    }
1701                }
1702                TypeDefKind::Future(_) => todo!(),
1703                TypeDefKind::Stream(_) => todo!(),
1704                TypeDefKind::Type(ty) => self.type_name(ty, from_namespace, flavor),
1705                TypeDefKind::FixedSizeList(ty, size) => {
1706                    self.r#gen.dependencies.needs_array = true;
1707                    format!(
1708                        "std::array<{}, {size}>",
1709                        self.type_name(ty, from_namespace, flavor)
1710                    )
1711                }
1712                TypeDefKind::Map(_, _) => todo!(),
1713                TypeDefKind::Unknown => todo!(),
1714            },
1715            Type::ErrorContext => todo!(),
1716        }
1717    }
1718
1719    fn declare_import2(
1720        &self,
1721        module_name: &str,
1722        name: &str,
1723        args: &str,
1724        result: &str,
1725        variant: AbiVariant,
1726    ) -> (String, String) {
1727        let mut extern_name = String::from("__wasm_import_");
1728        extern_name.push_str(&make_external_symbol(module_name, name, variant));
1729        let import = format!(
1730            "extern \"C\" __attribute__((import_module(\"{module_name}\")))\n __attribute__((import_name(\"{name}\")))\n {result} {extern_name}({args});\n"
1731        );
1732        (extern_name, import)
1733    }
1734
1735    fn declare_import(
1736        &mut self,
1737        module_name: &str,
1738        name: &str,
1739        params: &[WasmType],
1740        results: &[WasmType],
1741    ) -> String {
1742        let mut args = String::default();
1743        for (n, param) in params.iter().enumerate() {
1744            args.push_str(wit_bindgen_c::wasm_type(*param));
1745            if n + 1 != params.len() {
1746                args.push_str(", ");
1747            }
1748        }
1749        let result = if results.is_empty() {
1750            "void"
1751        } else {
1752            wit_bindgen_c::wasm_type(results[0])
1753        };
1754        let variant = AbiVariant::GuestImport;
1755        let (name, code) = self.declare_import2(module_name, name, &args, result, variant);
1756        self.r#gen.extern_c_decls.push_str(&code);
1757        name
1758    }
1759
1760    fn docs(src: &mut Source, docs: &Docs) {
1761        if let Some(docs) = docs.contents.as_ref() {
1762            for line in docs.trim().lines() {
1763                src.push_str("/// ");
1764                src.push_str(line);
1765                src.push_str("\n");
1766            }
1767        }
1768    }
1769
1770    fn type_record_param(
1771        &mut self,
1772        id: TypeId,
1773        name: &str,
1774        record: &wit_bindgen_core::wit_parser::Record,
1775        namespc: &[String],
1776    ) {
1777        let (flavor, needs_param_type) = {
1778            match self.r#gen.opts.ownership {
1779                Ownership::Owning => (Flavor::InStruct, false),
1780                Ownership::CoarseBorrowing => {
1781                    if self.r#gen.types.get(id).has_own_handle {
1782                        (Flavor::InStruct, false)
1783                    } else {
1784                        (Flavor::BorrowedArgument, true)
1785                    }
1786                }
1787                Ownership::FineBorrowing => (Flavor::BorrowedArgument, true),
1788            }
1789        };
1790
1791        if needs_param_type {
1792            let pascal = format!("{name}-param").to_pascal_case();
1793
1794            uwriteln!(self.r#gen.h_src.src, "struct {pascal} {{");
1795            for field in record.fields.iter() {
1796                let typename = self.type_name(&field.ty, namespc, flavor);
1797                let fname = to_c_ident(&field.name);
1798                uwriteln!(self.r#gen.h_src.src, "{typename} {fname};");
1799            }
1800            uwriteln!(self.r#gen.h_src.src, "}};");
1801        }
1802    }
1803
1804    fn is_exported_type(&self, ty: &TypeDef) -> bool {
1805        match ty.owner {
1806            TypeOwner::Interface(intf) => {
1807                // For resources used in export functions, check if the resource's owner
1808                // interface is in imported_interfaces (which was populated during import())
1809                !self.r#gen.imported_interfaces.contains(&intf)
1810            }
1811            TypeOwner::World(_) => {
1812                // World-level resources are treated as imports, not exports
1813                false
1814            }
1815            TypeOwner::None => true,
1816        }
1817    }
1818}
1819
1820impl<'a> wit_bindgen_core::InterfaceGenerator<'a> for CppInterfaceGenerator<'a> {
1821    fn resolve(&self) -> &'a Resolve {
1822        self.resolve
1823    }
1824
1825    fn type_record(
1826        &mut self,
1827        id: TypeId,
1828        name: &str,
1829        record: &wit_bindgen_core::wit_parser::Record,
1830        docs: &wit_bindgen_core::wit_parser::Docs,
1831    ) {
1832        let ty = &self.resolve.types[id];
1833        let guest_export = self.is_exported_type(ty);
1834        let namespc = namespace(self.resolve, &ty.owner, guest_export, &self.r#gen.opts);
1835
1836        if self.r#gen.is_first_definition(&namespc, name) {
1837            self.r#gen.h_src.change_namespace(&namespc);
1838            Self::docs(&mut self.r#gen.h_src.src, docs);
1839            let pascal = name.to_pascal_case();
1840
1841            uwriteln!(self.r#gen.h_src.src, "struct {pascal} {{");
1842            for field in record.fields.iter() {
1843                Self::docs(&mut self.r#gen.h_src.src, &field.docs);
1844                let typename = self.type_name(&field.ty, &namespc, Flavor::InStruct);
1845                let fname = to_c_ident(&field.name);
1846                uwriteln!(self.r#gen.h_src.src, "{typename} {fname};");
1847            }
1848            uwriteln!(self.r#gen.h_src.src, "}};");
1849            self.type_record_param(id, name, record, namespc.as_slice());
1850        }
1851    }
1852
1853    fn type_resource(
1854        &mut self,
1855        id: TypeId,
1856        name: &str,
1857        _docs: &wit_bindgen_core::wit_parser::Docs,
1858    ) {
1859        let type_ = &self.resolve.types[id];
1860        if let TypeOwner::Interface(intf) = type_.owner {
1861            let guest_import = self.r#gen.imported_interfaces.contains(&intf);
1862            let definition = !(guest_import);
1863            let store = self.r#gen.start_new_file(Some(definition));
1864            let mut world_name = to_c_ident(&self.r#gen.world);
1865            world_name.push_str("::");
1866            let namespc = namespace(self.resolve, &type_.owner, !guest_import, &self.r#gen.opts);
1867            let pascal = name.to_upper_camel_case();
1868            let mut user_filename = namespc.clone();
1869            user_filename.push(pascal.clone());
1870            if definition {
1871                uwriteln!(
1872                    self.r#gen.h_src.src,
1873                    r#"/* User class definition file, autogenerated once, then user modified
1874                    * Updated versions of this file are generated into {pascal}.template.
1875                    */"#
1876                );
1877            }
1878            self.r#gen.h_src.change_namespace(&namespc);
1879
1880            if !definition {
1881                self.r#gen.dependencies.needs_imported_resources = true;
1882            } else {
1883                self.r#gen.dependencies.needs_exported_resources = true;
1884            }
1885            self.r#gen.dependencies.needs_wit = true;
1886
1887            let base_type = match (definition, false) {
1888                (true, false) => format!("wit::{RESOURCE_EXPORT_BASE_CLASS_NAME}<{pascal}>"),
1889                (false, false) => {
1890                    String::from_str("wit::").unwrap() + RESOURCE_IMPORT_BASE_CLASS_NAME
1891                }
1892                (false, true) => {
1893                    String::from_str("wit::").unwrap() + RESOURCE_EXPORT_BASE_CLASS_NAME
1894                }
1895                (true, true) => format!("wit::{RESOURCE_IMPORT_BASE_CLASS_NAME}<{pascal}>"),
1896            };
1897            let derive = format!(" : public {base_type}");
1898            uwriteln!(self.r#gen.h_src.src, "class {pascal}{derive} {{\n");
1899            uwriteln!(self.r#gen.h_src.src, "public:\n");
1900            let variant = if guest_import {
1901                AbiVariant::GuestImport
1902            } else {
1903                AbiVariant::GuestExport
1904            };
1905            {
1906                // destructor
1907                let name = match variant {
1908                    AbiVariant::GuestImport => "[resource-drop]",
1909                    AbiVariant::GuestExport => "[dtor]",
1910                    AbiVariant::GuestImportAsync => todo!(),
1911                    AbiVariant::GuestExportAsync => todo!(),
1912                    AbiVariant::GuestExportAsyncStackful => todo!(),
1913                }
1914                .to_string()
1915                    + name;
1916                let func = Function {
1917                    name,
1918                    kind: FunctionKind::Static(id),
1919                    params: vec![("self".into(), Type::Id(id))],
1920                    result: None,
1921                    docs: Docs::default(),
1922                    stability: Stability::Unknown,
1923                };
1924                self.generate_function(&func, &TypeOwner::Interface(intf), variant);
1925            }
1926            let funcs = self.resolve.interfaces[intf].functions.values();
1927            for func in funcs {
1928                if match &func.kind {
1929                    FunctionKind::Freestanding => false,
1930                    FunctionKind::Method(mid) => *mid == id,
1931                    FunctionKind::Static(mid) => *mid == id,
1932                    FunctionKind::Constructor(mid) => *mid == id,
1933                    FunctionKind::AsyncFreestanding => todo!(),
1934                    FunctionKind::AsyncMethod(_id) => todo!(),
1935                    FunctionKind::AsyncStatic(_id) => todo!(),
1936                } {
1937                    self.generate_function(func, &TypeOwner::Interface(intf), variant);
1938                    // For non-fallible constructors on export side, generate a New allocator method
1939                    // For fallible constructors, the user provides their own Create method
1940                    let is_fallible_constructor =
1941                        self.r#gen.is_fallible_constructor(self.resolve, func);
1942
1943                    if matches!(func.kind, FunctionKind::Constructor(_))
1944                        && matches!(variant, AbiVariant::GuestExport)
1945                        && !is_fallible_constructor
1946                    {
1947                        // functional safety requires the option to use a different allocator, so move new into the implementation
1948                        let func2 = Function {
1949                            name: "$alloc".to_string(),
1950                            kind: FunctionKind::Static(id),
1951                            // same params as constructor
1952                            params: func.params.clone(),
1953                            result: Some(Type::Id(id)),
1954                            docs: Docs::default(),
1955                            stability: Stability::Unknown,
1956                        };
1957                        self.generate_function(&func2, &TypeOwner::Interface(intf), variant);
1958                    }
1959                }
1960            }
1961
1962            if !definition {
1963                // consuming constructor from handle (bindings)
1964                uwriteln!(self.r#gen.h_src.src, "{pascal}({base_type} &&);",);
1965                uwriteln!(self.r#gen.h_src.src, "{pascal}({pascal}&&) = default;");
1966                uwriteln!(
1967                    self.r#gen.h_src.src,
1968                    "{pascal}& operator=({pascal}&&) = default;"
1969                );
1970                self.r#gen.c_src.qualify(&namespc);
1971                uwriteln!(
1972                    self.r#gen.c_src.src,
1973                    "{pascal}::{pascal}({base_type}&&b) : {base_type}(std::move(b)) {{}}"
1974                );
1975            }
1976            if matches!(variant, AbiVariant::GuestExport) {
1977                let id_type = Type::S32;
1978                let func = Function {
1979                    name: "[resource-new]".to_string() + name,
1980                    kind: FunctionKind::Static(id),
1981                    params: vec![("self".into(), Type::Id(id))],
1982                    result: Some(id_type),
1983                    docs: Docs::default(),
1984                    stability: Stability::Unknown,
1985                };
1986                self.generate_function(&func, &TypeOwner::Interface(intf), variant);
1987
1988                let func1 = Function {
1989                    name: "[resource-rep]".to_string() + name,
1990                    kind: FunctionKind::Static(id),
1991                    params: vec![("id".into(), id_type)],
1992                    result: Some(Type::Id(id)),
1993                    docs: Docs::default(),
1994                    stability: Stability::Unknown,
1995                };
1996                self.generate_function(&func1, &TypeOwner::Interface(intf), variant);
1997
1998                let func2 = Function {
1999                    name: "[resource-drop]".to_string() + name,
2000                    kind: FunctionKind::Static(id),
2001                    params: vec![("id".into(), id_type)],
2002                    result: None,
2003                    docs: Docs::default(),
2004                    stability: Stability::Unknown,
2005                };
2006                self.generate_function(&func2, &TypeOwner::Interface(intf), variant);
2007            }
2008            uwriteln!(self.r#gen.h_src.src, "}};\n");
2009            self.r#gen.finish_file(&user_filename, store);
2010        } else if matches!(type_.owner, TypeOwner::World(_)) {
2011            // Handle world-level resources - treat as imported resources
2012            let guest_export = false; // World-level resources are treated as imports
2013            let namespc = namespace(self.resolve, &type_.owner, guest_export, &self.r#gen.opts);
2014            self.r#gen.h_src.change_namespace(&namespc);
2015
2016            let pascal = name.to_upper_camel_case();
2017            self.r#gen.dependencies.needs_imported_resources = true;
2018            self.r#gen.dependencies.needs_wit = true;
2019
2020            let base_type = format!("wit::{RESOURCE_IMPORT_BASE_CLASS_NAME}");
2021            let derive = format!(" : public {base_type}");
2022            uwriteln!(self.r#gen.h_src.src, "class {pascal}{derive}{{\n");
2023            uwriteln!(self.r#gen.h_src.src, "public:\n");
2024
2025            // Add destructor and constructor
2026            uwriteln!(self.r#gen.h_src.src, "~{pascal}();");
2027            uwriteln!(
2028                self.r#gen.h_src.src,
2029                "{pascal}(wit::{RESOURCE_IMPORT_BASE_CLASS_NAME} &&);"
2030            );
2031            uwriteln!(self.r#gen.h_src.src, "{pascal}({pascal}&&) = default;");
2032            uwriteln!(
2033                self.r#gen.h_src.src,
2034                "{pascal}& operator=({pascal}&&) = default;"
2035            );
2036            uwriteln!(self.r#gen.h_src.src, "}};\n");
2037        }
2038    }
2039
2040    fn type_flags(
2041        &mut self,
2042        id: TypeId,
2043        name: &str,
2044        flags: &wit_bindgen_core::wit_parser::Flags,
2045        docs: &wit_bindgen_core::wit_parser::Docs,
2046    ) {
2047        let ty = &self.resolve.types[id];
2048        let guest_export = self.is_exported_type(ty);
2049        let namespc = namespace(self.resolve, &ty.owner, guest_export, &self.r#gen.opts);
2050        if self.r#gen.is_first_definition(&namespc, name) {
2051            self.r#gen.h_src.change_namespace(&namespc);
2052            Self::docs(&mut self.r#gen.h_src.src, docs);
2053            let pascal = name.to_pascal_case();
2054            let int_repr = wit_bindgen_c::int_repr(wit_bindgen_c::flags_repr(flags));
2055            uwriteln!(self.r#gen.h_src.src, "enum class {pascal} : {int_repr} {{");
2056            uwriteln!(self.r#gen.h_src.src, "k_None = 0,");
2057            for (n, field) in flags.flags.iter().enumerate() {
2058                Self::docs(&mut self.r#gen.h_src.src, &field.docs);
2059                let fname = to_c_ident(&field.name).to_pascal_case();
2060                uwriteln!(self.r#gen.h_src.src, "k{fname} = (1ULL<<{n}),");
2061            }
2062            uwriteln!(self.r#gen.h_src.src, "}};");
2063            uwriteln!(
2064                self.r#gen.h_src.src,
2065                r#"static inline {pascal} operator|({pascal} a, {pascal} b) {{ return {pascal}({int_repr}(a)|{int_repr}(b)); }}
2066        static inline {pascal} operator&({pascal} a, {pascal} b) {{ return {pascal}({int_repr}(a)&{int_repr}(b)); }}"#
2067            );
2068        }
2069    }
2070
2071    fn type_tuple(
2072        &mut self,
2073        _id: TypeId,
2074        _name: &str,
2075        _flags: &wit_bindgen_core::wit_parser::Tuple,
2076        _docs: &wit_bindgen_core::wit_parser::Docs,
2077    ) {
2078        // I assume I don't need to do anything ...
2079    }
2080
2081    fn type_variant(
2082        &mut self,
2083        id: TypeId,
2084        name: &str,
2085        variant: &wit_bindgen_core::wit_parser::Variant,
2086        docs: &wit_bindgen_core::wit_parser::Docs,
2087    ) {
2088        let ty = &self.resolve.types[id];
2089        let guest_export = self.is_exported_type(ty);
2090        let namespc = namespace(self.resolve, &ty.owner, guest_export, &self.r#gen.opts);
2091        if self.r#gen.is_first_definition(&namespc, name) {
2092            self.r#gen.h_src.change_namespace(&namespc);
2093            Self::docs(&mut self.r#gen.h_src.src, docs);
2094            let pascal = name.to_pascal_case();
2095            uwriteln!(self.r#gen.h_src.src, "struct {pascal} {{");
2096            let mut inner_namespace = namespc.clone();
2097            inner_namespace.push(pascal.clone());
2098            let mut all_types = String::new();
2099            for case in variant.cases.iter() {
2100                Self::docs(&mut self.r#gen.h_src.src, &case.docs);
2101                let case_pascal = to_c_ident(&case.name).to_pascal_case();
2102                if !all_types.is_empty() {
2103                    all_types += ", ";
2104                }
2105                all_types += &case_pascal;
2106                uwrite!(self.r#gen.h_src.src, "struct {case_pascal} {{");
2107                if let Some(ty) = case.ty.as_ref() {
2108                    let typestr = self.type_name(ty, &inner_namespace, Flavor::InStruct);
2109                    uwrite!(self.r#gen.h_src.src, " {typestr} value; ")
2110                }
2111                uwriteln!(self.r#gen.h_src.src, "}};");
2112            }
2113            uwriteln!(
2114                self.r#gen.h_src.src,
2115                "  std::variant<{all_types}> variants;"
2116            );
2117            uwriteln!(self.r#gen.h_src.src, "}};");
2118            self.r#gen.dependencies.needs_variant = true;
2119        }
2120    }
2121
2122    fn type_option(
2123        &mut self,
2124        _id: TypeId,
2125        _name: &str,
2126        _payload: &wit_bindgen_core::wit_parser::Type,
2127        _docs: &wit_bindgen_core::wit_parser::Docs,
2128    ) {
2129        // nothing to do here
2130    }
2131
2132    fn type_result(
2133        &mut self,
2134        _id: TypeId,
2135        _name: &str,
2136        _result: &wit_bindgen_core::wit_parser::Result_,
2137        _docs: &wit_bindgen_core::wit_parser::Docs,
2138    ) {
2139        // nothing to do here
2140    }
2141
2142    fn type_enum(
2143        &mut self,
2144        id: TypeId,
2145        name: &str,
2146        enum_: &wit_bindgen_core::wit_parser::Enum,
2147        docs: &wit_bindgen_core::wit_parser::Docs,
2148    ) {
2149        let ty = &self.resolve.types[id];
2150        let guest_export = self.is_exported_type(ty);
2151        let namespc = namespace(self.resolve, &ty.owner, guest_export, &self.r#gen.opts);
2152        if self.r#gen.is_first_definition(&namespc, name) {
2153            self.r#gen.h_src.change_namespace(&namespc);
2154            let pascal = name.to_pascal_case();
2155            Self::docs(&mut self.r#gen.h_src.src, docs);
2156            let int_t = wit_bindgen_c::int_repr(enum_.tag());
2157            uwriteln!(self.r#gen.h_src.src, "enum class {pascal} : {int_t} {{");
2158            for (i, case) in enum_.cases.iter().enumerate() {
2159                Self::docs(&mut self.r#gen.h_src.src, &case.docs);
2160                uwriteln!(
2161                    self.r#gen.h_src.src,
2162                    " k{} = {i},",
2163                    to_c_ident(&case.name).to_pascal_case(),
2164                );
2165            }
2166            uwriteln!(self.r#gen.h_src.src, "}};\n");
2167        }
2168    }
2169
2170    fn type_alias(
2171        &mut self,
2172        id: TypeId,
2173        name: &str,
2174        alias_type: &wit_bindgen_core::wit_parser::Type,
2175        docs: &wit_bindgen_core::wit_parser::Docs,
2176    ) {
2177        let ty = &self.resolve.types[id];
2178        let guest_export = self.is_exported_type(ty);
2179        let namespc = namespace(self.resolve, &ty.owner, guest_export, &self.r#gen.opts);
2180        self.r#gen.h_src.change_namespace(&namespc);
2181        let pascal = name.to_pascal_case();
2182        Self::docs(&mut self.r#gen.h_src.src, docs);
2183        let typename = self.type_name(alias_type, &namespc, Flavor::InStruct);
2184        uwriteln!(self.r#gen.h_src.src, "using {pascal} = {typename};");
2185    }
2186
2187    fn type_list(
2188        &mut self,
2189        _id: TypeId,
2190        _name: &str,
2191        _ty: &wit_bindgen_core::wit_parser::Type,
2192        _docs: &wit_bindgen_core::wit_parser::Docs,
2193    ) {
2194        // nothing to do here
2195    }
2196
2197    fn type_builtin(
2198        &mut self,
2199        _id: TypeId,
2200        _name: &str,
2201        _ty: &wit_bindgen_core::wit_parser::Type,
2202        _docs: &wit_bindgen_core::wit_parser::Docs,
2203    ) {
2204        todo!()
2205    }
2206
2207    fn type_future(&mut self, _id: TypeId, _name: &str, _ty: &Option<Type>, _docs: &Docs) {
2208        todo!()
2209    }
2210
2211    fn type_stream(&mut self, _id: TypeId, _name: &str, _ty: &Option<Type>, _docs: &Docs) {
2212        todo!()
2213    }
2214}
2215
2216struct CabiPostInformation {
2217    module: String,
2218    name: String,
2219    ret_type: String,
2220}
2221
2222struct FunctionBindgen<'a, 'b> {
2223    r#gen: &'b mut CppInterfaceGenerator<'a>,
2224    params: Vec<String>,
2225    tmp: usize,
2226    namespace: Vec<String>,
2227    src: Source,
2228    block_storage: Vec<wit_bindgen_core::Source>,
2229    /// intermediate calculations for contained objects
2230    blocks: Vec<(String, Vec<String>)>,
2231    payloads: Vec<String>,
2232    // caching for wasm
2233    variant: AbiVariant,
2234    cabi_post: Option<CabiPostInformation>,
2235    needs_dealloc: bool,
2236    leak_on_insertion: Option<String>,
2237    return_pointer_area_size: ArchitectureSize,
2238    return_pointer_area_align: Alignment,
2239}
2240
2241impl<'a, 'b> FunctionBindgen<'a, 'b> {
2242    fn new(r#gen: &'b mut CppInterfaceGenerator<'a>, params: Vec<String>) -> Self {
2243        Self {
2244            r#gen,
2245            params,
2246            tmp: 0,
2247            namespace: Default::default(),
2248            src: Default::default(),
2249            block_storage: Default::default(),
2250            blocks: Default::default(),
2251            payloads: Default::default(),
2252            variant: AbiVariant::GuestImport,
2253            cabi_post: None,
2254            needs_dealloc: false,
2255            leak_on_insertion: None,
2256            return_pointer_area_size: Default::default(),
2257            return_pointer_area_align: Default::default(),
2258        }
2259    }
2260
2261    fn tmp(&mut self) -> usize {
2262        let ret = self.tmp;
2263        self.tmp += 1;
2264        ret
2265    }
2266
2267    fn tempname(&self, base: &str, idx: usize) -> String {
2268        format!("{base}{idx}")
2269    }
2270
2271    fn push_str(&mut self, s: &str) {
2272        self.src.push_str(s);
2273    }
2274
2275    fn let_results(&mut self, amt: usize, results: &mut Vec<String>) {
2276        if amt > 0 {
2277            let tmp = self.tmp();
2278            let res = format!("result{tmp}");
2279            self.push_str("auto ");
2280            self.push_str(&res);
2281            self.push_str(" = ");
2282            if amt == 1 {
2283                results.push(res);
2284            } else {
2285                for i in 0..amt {
2286                    results.push(format!("std::get<{i}>({res})"));
2287                }
2288            }
2289        }
2290    }
2291
2292    fn load(
2293        &mut self,
2294        ty: &str,
2295        offset: ArchitectureSize,
2296        operands: &[String],
2297        results: &mut Vec<String>,
2298    ) {
2299        results.push(format!(
2300            "*(({}*) ({} + {}))",
2301            ty,
2302            operands[0],
2303            offset.format(POINTER_SIZE_EXPRESSION)
2304        ));
2305    }
2306
2307    fn load_ext(
2308        &mut self,
2309        ty: &str,
2310        offset: ArchitectureSize,
2311        operands: &[String],
2312        results: &mut Vec<String>,
2313    ) {
2314        self.load(ty, offset, operands, results);
2315        let result = results.pop().unwrap();
2316        results.push(format!("(int32_t) ({result})"));
2317    }
2318
2319    fn store(&mut self, ty: &str, offset: ArchitectureSize, operands: &[String]) {
2320        uwriteln!(
2321            self.src,
2322            "*(({}*)({} + {})) = {};",
2323            ty,
2324            operands[1],
2325            offset.format(POINTER_SIZE_EXPRESSION),
2326            operands[0]
2327        );
2328    }
2329
2330    /// Emits a shared return area declaration if needed by this function.
2331    ///
2332    /// During code generation, `return_pointer()` may be called multiple times for:
2333    /// - Indirect parameter storage (when too many/large params)
2334    /// - Return value storage (when return type is too large)
2335    ///
2336    /// **Safety:** This is safe because return pointers are used sequentially:
2337    /// 1. Parameter marshaling (before call)
2338    /// 2. Function execution
2339    /// 3. Return value unmarshaling (after call)
2340    ///
2341    /// The scratch space is reused but never accessed simultaneously.
2342    fn emit_ret_area_if_needed(&self) -> String {
2343        if !self.return_pointer_area_size.is_empty() {
2344            let size_string = self
2345                .return_pointer_area_size
2346                .format(POINTER_SIZE_EXPRESSION);
2347            let tp = match self.return_pointer_area_align {
2348                Alignment::Bytes(bytes) => match bytes.get() {
2349                    1 => "uint8_t",
2350                    2 => "uint16_t",
2351                    4 => "uint32_t",
2352                    8 => "uint64_t",
2353                    // Fallback to uint8_t for unusual alignments (e.g., 16-byte SIMD).
2354                    // This is safe: the size calculation ensures correct buffer size,
2355                    // and uint8_t arrays can store any data regardless of alignment.
2356                    _ => "uint8_t",
2357                },
2358                Alignment::Pointer => "uintptr_t",
2359            };
2360            let static_var = if self.r#gen.in_guest_import {
2361                ""
2362            } else {
2363                "static "
2364            };
2365            format!("{static_var}{tp} ret_area[({size_string}+sizeof({tp})-1)/sizeof({tp})];\n")
2366        } else {
2367            String::new()
2368        }
2369    }
2370}
2371
2372fn move_if_necessary(arg: &str) -> String {
2373    // if it is a name of a variable move it
2374    if !arg.is_empty() && arg.chars().all(char::is_alphanumeric) {
2375        format!("std::move({arg})")
2376    } else {
2377        arg.into()
2378    }
2379}
2380
2381impl<'a, 'b> Bindgen for FunctionBindgen<'a, 'b> {
2382    type Operand = String;
2383
2384    fn emit(
2385        &mut self,
2386        _resolve: &Resolve,
2387        inst: &wit_bindgen_core::abi::Instruction<'_>,
2388        operands: &mut Vec<Self::Operand>,
2389        results: &mut Vec<Self::Operand>,
2390    ) {
2391        let mut top_as = |cvt: &str| {
2392            results.push(format!("({cvt}({}))", operands.pop().unwrap()));
2393        };
2394
2395        match inst {
2396            abi::Instruction::GetArg { nth } => {
2397                if *nth == 0 && self.params[0].as_str() == "self" {
2398                    if self.r#gen.in_guest_import {
2399                        results.push("(*this)".to_string());
2400                    } else {
2401                        results.push("(*lookup_resource(self))".to_string());
2402                    }
2403                } else {
2404                    results.push(self.params[*nth].clone());
2405                }
2406            }
2407            abi::Instruction::I32Const { val } => results.push(format!("(int32_t({val}))")),
2408            abi::Instruction::Bitcasts { casts } => {
2409                for (cast, op) in casts.iter().zip(operands) {
2410                    // let op = op;
2411                    results.push(self.r#gen.r#gen.perform_cast(op, cast));
2412                }
2413            }
2414            abi::Instruction::ConstZero { tys } => {
2415                for ty in tys.iter() {
2416                    match ty {
2417                        WasmType::I32 => results.push("int32_t(0)".to_string()),
2418                        WasmType::I64 => results.push("int64_t(0)".to_string()),
2419                        WasmType::F32 => results.push("0.0f".to_string()),
2420                        WasmType::F64 => results.push("0.0".to_string()),
2421                        WasmType::Length => results.push("size_t(0)".to_string()),
2422                        WasmType::Pointer => results.push("nullptr".to_string()),
2423                        WasmType::PointerOrI64 => results.push("int64_t(0)".to_string()),
2424                    }
2425                }
2426            }
2427            abi::Instruction::I32Load { offset } => {
2428                let tmp = self.tmp();
2429                uwriteln!(
2430                    self.src,
2431                    "int32_t l{tmp} = *((int32_t const*)({} + {offset}));",
2432                    operands[0],
2433                    offset = offset.format(POINTER_SIZE_EXPRESSION)
2434                );
2435                results.push(format!("l{tmp}"));
2436            }
2437            abi::Instruction::I32Load8U { offset } => {
2438                self.load_ext("uint8_t", *offset, operands, results)
2439            }
2440            abi::Instruction::I32Load8S { offset } => {
2441                self.load_ext("int8_t", *offset, operands, results)
2442            }
2443            abi::Instruction::I32Load16U { offset } => {
2444                self.load_ext("uint16_t", *offset, operands, results)
2445            }
2446            abi::Instruction::I32Load16S { offset } => {
2447                self.load_ext("int16_t", *offset, operands, results)
2448            }
2449            abi::Instruction::I64Load { offset } => {
2450                self.load("int64_t", *offset, operands, results)
2451            }
2452            abi::Instruction::F32Load { offset } => self.load("float", *offset, operands, results),
2453            abi::Instruction::F64Load { offset } => self.load("double", *offset, operands, results),
2454            abi::Instruction::I32Store { offset } => self.store("int32_t", *offset, operands),
2455            abi::Instruction::I32Store8 { offset } => self.store("int8_t", *offset, operands),
2456            abi::Instruction::I32Store16 { offset } => self.store("int16_t", *offset, operands),
2457            abi::Instruction::I64Store { offset } => self.store("int64_t", *offset, operands),
2458            abi::Instruction::F32Store { offset } => self.store("float", *offset, operands),
2459            abi::Instruction::F64Store { offset } => self.store("double", *offset, operands),
2460            abi::Instruction::I32FromChar
2461            | abi::Instruction::I32FromBool
2462            | abi::Instruction::I32FromU8
2463            | abi::Instruction::I32FromS8
2464            | abi::Instruction::I32FromU16
2465            | abi::Instruction::I32FromS16
2466            | abi::Instruction::I32FromU32
2467            | abi::Instruction::I32FromS32 => top_as("int32_t"),
2468            abi::Instruction::I64FromU64 | abi::Instruction::I64FromS64 => top_as("int64_t"),
2469            abi::Instruction::F32FromCoreF32 => top_as("float"),
2470            abi::Instruction::F64FromCoreF64 => top_as("double"),
2471            abi::Instruction::S8FromI32 => top_as("int8_t"),
2472            abi::Instruction::U8FromI32 => top_as("uint8_t"),
2473            abi::Instruction::S16FromI32 => top_as("int16_t"),
2474            abi::Instruction::U16FromI32 => top_as("uint16_t"),
2475            abi::Instruction::S32FromI32 => top_as("int32_t"),
2476            abi::Instruction::U32FromI32 => top_as("uint32_t"),
2477            abi::Instruction::S64FromI64 => top_as("int64_t"),
2478            abi::Instruction::U64FromI64 => top_as("uint64_t"),
2479            abi::Instruction::CharFromI32 => top_as("uint32_t"),
2480            abi::Instruction::CoreF32FromF32 => top_as("float"),
2481            abi::Instruction::CoreF64FromF64 => top_as("double"),
2482            abi::Instruction::BoolFromI32 => top_as("bool"),
2483            abi::Instruction::ListCanonLower { realloc, .. } => {
2484                let tmp = self.tmp();
2485                let val = format!("vec{tmp}");
2486                let ptr = format!("ptr{tmp}");
2487                let len = format!("len{tmp}");
2488                self.push_str(&format!("auto&& {} = {};\n", val, operands[0]));
2489                self.push_str(&format!(
2490                    "auto {} = ({})({}.data());\n",
2491                    ptr,
2492                    self.r#gen.r#gen.opts.ptr_type(),
2493                    val
2494                ));
2495                self.push_str(&format!("auto {len} = (size_t)({val}.size());\n"));
2496                if realloc.is_none() {
2497                    results.push(ptr);
2498                } else {
2499                    uwriteln!(self.src, "{}.leak();\n", operands[0]);
2500                    results.push(ptr);
2501                }
2502                results.push(len);
2503            }
2504            abi::Instruction::StringLower { realloc } => {
2505                let tmp = self.tmp();
2506                let val = format!("vec{tmp}");
2507                let ptr = format!("ptr{tmp}");
2508                let len = format!("len{tmp}");
2509                self.push_str(&format!("auto&& {} = {};\n", val, operands[0]));
2510                self.push_str(&format!(
2511                    "auto {} = ({})({}.data());\n",
2512                    ptr,
2513                    self.r#gen.r#gen.opts.ptr_type(),
2514                    val
2515                ));
2516                self.push_str(&format!("auto {len} = (size_t)({val}.size());\n"));
2517                if realloc.is_none() {
2518                    results.push(ptr);
2519                } else {
2520                    uwriteln!(self.src, "{}.leak();\n", operands[0]);
2521                    results.push(ptr);
2522                }
2523                results.push(len);
2524            }
2525            abi::Instruction::ListLower { element, realloc } => {
2526                let tmp = self.tmp();
2527                let body = self.blocks.pop().unwrap();
2528                let val = format!("vec{tmp}");
2529                let ptr = format!("ptr{tmp}");
2530                let len = format!("len{tmp}");
2531                let size = self.r#gen.sizes.size(element);
2532                self.push_str(&format!("auto&& {} = {};\n", val, operands[0]));
2533                self.push_str(&format!(
2534                    "auto {} = ({})({}.data());\n",
2535                    ptr,
2536                    self.r#gen.r#gen.opts.ptr_type(),
2537                    val
2538                ));
2539                self.push_str(&format!("auto {len} = (size_t)({val}.size());\n"));
2540                self.push_str(&format!("for (size_t i = 0; i < {len}; ++i) {{\n"));
2541                self.push_str(&format!(
2542                    "auto base = {ptr} + i * {size};\n",
2543                    size = size.format(POINTER_SIZE_EXPRESSION)
2544                ));
2545                self.push_str(&format!("auto&& iter_elem = {val}[i];\n"));
2546                self.push_str(&format!("{}\n", body.0));
2547                self.push_str("}\n");
2548                if realloc.is_none() {
2549                    results.push(ptr);
2550                } else {
2551                    uwriteln!(self.src, "{}.leak();\n", operands[0]);
2552                    results.push(ptr);
2553                }
2554                results.push(len);
2555            }
2556            abi::Instruction::ListCanonLift { element, .. } => {
2557                let tmp = self.tmp();
2558                let len = format!("len{tmp}");
2559                let inner = self
2560                    .r#gen
2561                    .type_name(element, &self.namespace, Flavor::InStruct);
2562                self.push_str(&format!("auto {} = {};\n", len, operands[1]));
2563                let result = if self.r#gen.r#gen.opts.api_style == APIStyle::Symmetric
2564                    && matches!(self.variant, AbiVariant::GuestExport)
2565                {
2566                    format!(
2567                        "wit::vector<{inner} const>(({inner}*)({}), {len}).get_view()",
2568                        operands[0]
2569                    )
2570                } else {
2571                    format!("wit::vector<{inner}>(({inner}*)({}), {len})", operands[0])
2572                };
2573                results.push(result);
2574            }
2575            abi::Instruction::StringLift => {
2576                let tmp = self.tmp();
2577                let len = format!("len{tmp}");
2578                uwriteln!(self.src, "auto {} = {};\n", len, operands[1]);
2579                let result = if self.r#gen.r#gen.opts.api_style == APIStyle::Symmetric
2580                    && matches!(self.variant, AbiVariant::GuestExport)
2581                {
2582                    assert!(self.needs_dealloc);
2583                    uwriteln!(
2584                        self.src,
2585                        "if ({len}>0) _deallocate.push_back({});\n",
2586                        operands[0]
2587                    );
2588                    format!("std::string_view((char const*)({}), {len})", operands[0])
2589                } else {
2590                    format!("wit::string((char const*)({}), {len})", operands[0])
2591                };
2592                results.push(result);
2593            }
2594            abi::Instruction::ListLift { element, .. } => {
2595                let body = self.blocks.pop().unwrap();
2596                let tmp = self.tmp();
2597                let size = self.r#gen.sizes.size(element);
2598                let _align = self.r#gen.sizes.align(element);
2599                let flavor = if self.r#gen.r#gen.opts.api_style == APIStyle::Symmetric
2600                    && matches!(self.variant, AbiVariant::GuestExport)
2601                {
2602                    Flavor::BorrowedArgument
2603                } else {
2604                    Flavor::InStruct
2605                };
2606                let vtype = self.r#gen.type_name(element, &self.namespace, flavor);
2607                let len = format!("len{tmp}");
2608                let base = format!("base{tmp}");
2609                let result = format!("result{tmp}");
2610                self.push_str(&format!(
2611                    "auto {base} = {operand0};\n",
2612                    operand0 = operands[0]
2613                ));
2614                self.push_str(&format!(
2615                    "auto {len} = {operand1};\n",
2616                    operand1 = operands[1]
2617                ));
2618                self.push_str(&format!(
2619                    r#"auto {result} = wit::vector<{vtype}>::allocate({len});
2620                    "#,
2621                ));
2622
2623                if self.r#gen.r#gen.opts.api_style == APIStyle::Symmetric
2624                    && matches!(self.variant, AbiVariant::GuestExport)
2625                {
2626                    assert!(self.needs_dealloc);
2627                    self.push_str(&format!("if ({len}>0) _deallocate.push_back({base});\n"));
2628                }
2629
2630                uwriteln!(self.src, "for (unsigned i=0; i<{len}; ++i) {{");
2631                uwriteln!(
2632                    self.src,
2633                    "auto base = {base} + i * {size};",
2634                    size = size.format(POINTER_SIZE_EXPRESSION)
2635                );
2636                uwrite!(self.src, "{}", body.0);
2637                uwriteln!(self.src, "auto e{tmp} = {};", move_if_necessary(&body.1[0]));
2638                if let Some(code) = self.leak_on_insertion.take() {
2639                    assert!(self.needs_dealloc);
2640                    uwriteln!(self.src, "{code}");
2641                }
2642                // inplace construct
2643                uwriteln!(self.src, "{result}.initialize(i, std::move(e{tmp}));");
2644                uwriteln!(self.src, "}}");
2645
2646                if self.r#gen.r#gen.opts.api_style == APIStyle::Symmetric
2647                    && matches!(self.variant, AbiVariant::GuestExport)
2648                {
2649                    results.push(format!("{result}.get_const_view()"));
2650                    if self.r#gen.r#gen.opts.api_style == APIStyle::Symmetric
2651                        && matches!(self.variant, AbiVariant::GuestExport)
2652                    {
2653                        self.leak_on_insertion.replace(format!(
2654                            "if ({len}>0) _deallocate.push_back((void*){result}.leak());\n"
2655                        ));
2656                    }
2657                } else {
2658                    results.push(move_if_necessary(&result));
2659                }
2660            }
2661            abi::Instruction::FixedLengthListLift {
2662                element,
2663                size,
2664                id: _,
2665            } => {
2666                let tmp = self.tmp();
2667                let result = format!("result{tmp}");
2668                let typename = self
2669                    .r#gen
2670                    .type_name(element, &self.namespace, Flavor::InStruct);
2671                self.push_str(&format!("std::array<{typename}, {size}> {result} = {{",));
2672                for a in operands.drain(0..(*size as usize)) {
2673                    self.push_str(&a);
2674                    self.push_str(", ");
2675                }
2676                self.push_str("};\n");
2677                results.push(result);
2678            }
2679            abi::Instruction::FixedLengthListLiftFromMemory {
2680                element,
2681                size: elemsize,
2682                id: _,
2683            } => {
2684                let body = self.blocks.pop().unwrap();
2685                let tmp = self.tmp();
2686                let vec = format!("array{tmp}");
2687                let source = operands[0].clone();
2688                let size = self.r#gen.sizes.size(element);
2689                let size_str = size.format(POINTER_SIZE_EXPRESSION);
2690                let typename = self
2691                    .r#gen
2692                    .type_name(element, &self.namespace, Flavor::InStruct);
2693                let ptr_type = self.r#gen.r#gen.opts.ptr_type();
2694                self.push_str(&format!("std::array<{typename}, {elemsize}> {vec};\n"));
2695                self.push_str(&format!(
2696                    "{{
2697                    {ptr_type} outer_base = {source};\n"
2698                ));
2699                let source: String = "outer_base".into();
2700                // let vec: String = "outer_vec".into();
2701                self.push_str(&format!("for (unsigned i = 0; i<{elemsize}; ++i) {{\n",));
2702                self.push_str(&format!("{ptr_type} base = {source} + i * {size_str};\n"));
2703                self.push_str(&body.0);
2704                self.push_str(&format!("{vec}[i] = {};", body.1[0]));
2705                self.push_str("\n}\n}\n");
2706                results.push(vec);
2707            }
2708            abi::Instruction::FixedLengthListLower {
2709                element: _,
2710                size,
2711                id: _,
2712            } => {
2713                for i in 0..(*size as usize) {
2714                    results.push(format!("{}[{i}]", operands[0]));
2715                }
2716            }
2717            abi::Instruction::FixedLengthListLowerToMemory {
2718                element,
2719                size: elemsize,
2720                id: _,
2721            } => {
2722                let body = self.blocks.pop().unwrap();
2723                let vec = operands[0].clone();
2724                let target = operands[1].clone();
2725                let size = self.r#gen.sizes.size(element);
2726                let size_str = size.format(POINTER_SIZE_EXPRESSION);
2727                let typename = self
2728                    .r#gen
2729                    .type_name(element, &self.namespace, Flavor::InStruct);
2730                let ptr_type = self.r#gen.r#gen.opts.ptr_type();
2731                self.push_str(&format!(
2732                    "{{
2733                    {ptr_type} outer_base = {target};\n"
2734                ));
2735                let target: String = "outer_base".into();
2736                self.push_str(&format!(
2737                    "std::array<{typename}, {elemsize}>& outer_vec = {vec};\n"
2738                ));
2739                let vec: String = "outer_vec".into();
2740                self.push_str(&format!("for (unsigned i = 0; i<{vec}.size(); ++i) {{\n",));
2741                self.push_str(&format!(
2742                    "{ptr_type} base = {target} + i * {size_str};
2743                     {typename}& iter_elem = {vec}[i];\n"
2744                ));
2745                self.push_str(&body.0);
2746                self.push_str("\n}\n}\n");
2747            }
2748            abi::Instruction::IterElem { .. } => results.push("iter_elem".to_string()),
2749            abi::Instruction::IterBasePointer => results.push("base".to_string()),
2750            abi::Instruction::RecordLower { record, .. } => {
2751                let op = &operands[0];
2752                for f in record.fields.iter() {
2753                    results.push(format!("({}).{}", op, to_c_ident(&f.name)));
2754                }
2755            }
2756            abi::Instruction::RecordLift { record, ty, .. } => {
2757                let mut result =
2758                    self.r#gen
2759                        .type_name(&Type::Id(*ty), &self.namespace, Flavor::InStruct);
2760                result.push('{');
2761                for (_field, val) in record.fields.iter().zip(operands) {
2762                    result.push_str(&(move_if_necessary(val) + ", "));
2763                }
2764                result.push('}');
2765                results.push(result);
2766            }
2767            abi::Instruction::HandleLower {
2768                handle: Handle::Own(ty),
2769                ..
2770            } => {
2771                let op = &operands[0];
2772
2773                // Check if this is an imported or exported resource
2774                let resource_ty = &self.r#gen.resolve.types[*ty];
2775                let resource_ty = match &resource_ty.kind {
2776                    TypeDefKind::Type(Type::Id(id)) => &self.r#gen.resolve.types[*id],
2777                    _ => resource_ty,
2778                };
2779                let is_exported = self.r#gen.is_exported_type(resource_ty);
2780
2781                if is_exported {
2782                    // Exported resources use .release()->handle
2783                    results.push(format!("{op}.release()->handle"));
2784                } else {
2785                    // Imported resources use .into_handle()
2786                    results.push(format!("{op}.into_handle()"));
2787                }
2788            }
2789            abi::Instruction::HandleLower {
2790                handle: Handle::Borrow(_),
2791                ..
2792            } => {
2793                let op = &operands[0];
2794                if op == "(*this)" {
2795                    // TODO is there a better way to decide?
2796                    results.push(format!("{op}.get_handle()"));
2797                } else {
2798                    results.push(format!("{op}.get().get_handle()"));
2799                }
2800            }
2801            abi::Instruction::HandleLift { handle, .. } => {
2802                let op = &operands[0];
2803                match (handle, false) {
2804                    (Handle::Own(ty), true) => match self.variant {
2805                        AbiVariant::GuestExport => {
2806                            results.push(format!("wit::{RESOURCE_EXPORT_BASE_CLASS_NAME}{{{op}}}"))
2807                        }
2808                        AbiVariant::GuestImport => {
2809                            let tmp = self.tmp();
2810                            let var = self.tempname("obj", tmp);
2811                            let tname = self.r#gen.type_name(
2812                                &Type::Id(*ty),
2813                                &self.namespace,
2814                                Flavor::Argument(self.variant),
2815                            );
2816                            uwriteln!(
2817                                self.src,
2818                                "auto {var} = {tname}::remove_resource({op});
2819                                assert({var}.has_value());"
2820                            );
2821                            results.push(format!("{tname}::Owned(*{var})"));
2822                        }
2823                        AbiVariant::GuestImportAsync => todo!(),
2824                        AbiVariant::GuestExportAsync => todo!(),
2825                        AbiVariant::GuestExportAsyncStackful => todo!(),
2826                    },
2827                    (Handle::Own(ty), false) => match self.variant {
2828                        AbiVariant::GuestImport => {
2829                            results.push(format!("wit::{RESOURCE_IMPORT_BASE_CLASS_NAME}{{{op}}}"))
2830                        }
2831                        AbiVariant::GuestExport => {
2832                            let tmp = self.tmp();
2833                            let var = self.tempname("obj", tmp);
2834                            let tname = self.r#gen.type_name(
2835                                &Type::Id(*ty),
2836                                &self.namespace,
2837                                Flavor::Argument(self.variant),
2838                            );
2839
2840                            // Check if this is an imported or exported resource
2841                            let resource_ty = &self.r#gen.resolve.types[*ty];
2842                            let resource_ty = match &resource_ty.kind {
2843                                TypeDefKind::Type(Type::Id(id)) => &self.r#gen.resolve.types[*id],
2844                                _ => resource_ty,
2845                            };
2846                            let is_exported = self.r#gen.is_exported_type(resource_ty);
2847
2848                            if is_exported {
2849                                // Exported resources use ::Owned typedef
2850                                uwriteln!(
2851                                    self.src,
2852                                    "auto {var} = {tname}::Owned({tname}::ResourceRep({op}));"
2853                                );
2854                            } else {
2855                                // Imported resources construct from ResourceImportBase
2856                                uwriteln!(
2857                                    self.src,
2858                                    "auto {var} = {tname}(wit::{RESOURCE_IMPORT_BASE_CLASS_NAME}{{{op}}});"
2859                                );
2860                            }
2861
2862                            results.push(format!("std::move({var})"))
2863                        }
2864                        AbiVariant::GuestImportAsync => todo!(),
2865                        AbiVariant::GuestExportAsync => todo!(),
2866                        AbiVariant::GuestExportAsyncStackful => todo!(),
2867                    },
2868                    (Handle::Borrow(ty), true) => {
2869                        let tname = self.r#gen.type_name(
2870                            &Type::Id(*ty),
2871                            &self.namespace,
2872                            Flavor::Argument(self.variant),
2873                        );
2874                        results.push(format!("**{tname}::lookup_resource({op})"));
2875                    }
2876                    (Handle::Borrow(ty), false) => match self.variant {
2877                        AbiVariant::GuestImport => results.push(op.clone()),
2878                        AbiVariant::GuestExport => {
2879                            let tname = self.r#gen.type_name(
2880                                &Type::Id(*ty),
2881                                &self.namespace,
2882                                Flavor::Argument(self.variant),
2883                            );
2884                            results.push(format!("std::ref(*({tname} *){op})"));
2885                        }
2886                        AbiVariant::GuestImportAsync => todo!(),
2887                        AbiVariant::GuestExportAsync => todo!(),
2888                        AbiVariant::GuestExportAsyncStackful => todo!(),
2889                    },
2890                }
2891            }
2892            abi::Instruction::TupleLower { tuple, .. } => {
2893                let op = &operands[0];
2894                for n in 0..tuple.types.len() {
2895                    results.push(format!("std::get<{n}>({op})"));
2896                }
2897            }
2898            abi::Instruction::TupleLift { tuple, .. } => {
2899                let name = format!("tuple{}", self.tmp());
2900                uwrite!(self.src, "auto {name} = std::tuple<");
2901                self.src.push_str(
2902                    &(tuple
2903                        .types
2904                        .iter()
2905                        .map(|t| self.r#gen.type_name(t, &self.namespace, Flavor::InStruct)))
2906                    .collect::<Vec<_>>()
2907                    .join(", "),
2908                );
2909                self.src.push_str(">(");
2910                self.src.push_str(
2911                    &operands
2912                        .iter()
2913                        .map(|op| move_if_necessary(op))
2914                        .collect::<Vec<_>>()
2915                        .join(", "),
2916                );
2917                self.src.push_str(");\n");
2918                results.push(format!("std::move({name})"));
2919            }
2920            abi::Instruction::FlagsLower { flags, ty, .. } => {
2921                match wit_bindgen_c::flags_repr(flags) {
2922                    Int::U8 | Int::U16 | Int::U32 => {
2923                        results.push(format!("((int32_t){})", operands.pop().unwrap()));
2924                    }
2925                    Int::U64 => {
2926                        let name =
2927                            self.r#gen
2928                                .type_name(&Type::Id(*ty), &self.namespace, Flavor::InStruct);
2929                        let tmp = self.tmp();
2930                        let tempname = self.tempname("flags", tmp);
2931                        uwriteln!(self.src, "{name} {tempname} = {};", operands[0]);
2932                        results.push(format!("(int32_t)(((uint64_t){tempname}) & 0xffffffff)"));
2933                        results.push(format!(
2934                            "(int32_t)((((uint64_t){tempname}) >> 32) & 0xffffffff)"
2935                        ));
2936                    }
2937                }
2938            }
2939            abi::Instruction::FlagsLift { flags, ty, .. } => {
2940                let typename =
2941                    self.r#gen
2942                        .type_name(&Type::Id(*ty), &self.namespace, Flavor::InStruct);
2943                match wit_bindgen_c::flags_repr(flags) {
2944                    Int::U8 | Int::U16 | Int::U32 => {
2945                        results.push(format!("(({typename}){})", operands.pop().unwrap()));
2946                    }
2947                    Int::U64 => {
2948                        let op0 = &operands[0];
2949                        let op1 = &operands[1];
2950                        results.push(format!(
2951                            "(({typename})(({op0}) | (((uint64_t)({op1})) << 32)))"
2952                        ));
2953                    }
2954                }
2955            }
2956            abi::Instruction::VariantPayloadName => {
2957                let name = format!("payload{}", self.tmp());
2958                results.push(name.clone());
2959                self.payloads.push(name);
2960            }
2961            abi::Instruction::VariantLower {
2962                variant,
2963                results: result_types,
2964                ty: var_ty,
2965                name: _var_name,
2966                ..
2967            } => {
2968                let blocks = self
2969                    .blocks
2970                    .drain(self.blocks.len() - variant.cases.len()..)
2971                    .collect::<Vec<_>>();
2972                let payloads = self
2973                    .payloads
2974                    .drain(self.payloads.len() - variant.cases.len()..)
2975                    .collect::<Vec<_>>();
2976
2977                let mut variant_results = Vec::with_capacity(result_types.len());
2978                for ty in result_types.iter() {
2979                    let name = format!("variant{}", self.tmp());
2980                    results.push(name.clone());
2981                    self.src.push_str(wit_bindgen_c::wasm_type(*ty));
2982                    self.src.push_str(" ");
2983                    self.src.push_str(&name);
2984                    self.src.push_str(";\n");
2985                    variant_results.push(name);
2986                }
2987
2988                let expr_to_match = format!("({}).variants.index()", operands[0]);
2989                let elem_ns =
2990                    self.r#gen
2991                        .type_name(&Type::Id(*var_ty), &self.namespace, Flavor::InStruct);
2992
2993                uwriteln!(self.src, "switch ((int32_t) {}) {{", expr_to_match);
2994                for (i, ((case, (block, block_results)), payload)) in
2995                    variant.cases.iter().zip(blocks).zip(payloads).enumerate()
2996                {
2997                    uwriteln!(self.src, "case {}: {{", i);
2998                    if case.ty.is_some() {
2999                        let case =
3000                            format!("{elem_ns}::{}", to_c_ident(&case.name).to_pascal_case());
3001                        uwriteln!(
3002                            self.src,
3003                            "auto& {} = std::get<{case}>({}.variants).value;",
3004                            payload,
3005                            operands[0],
3006                        );
3007                    }
3008
3009                    self.src.push_str(&block);
3010
3011                    for (name, result) in variant_results.iter().zip(&block_results) {
3012                        uwriteln!(self.src, "{} = {};", name, result);
3013                    }
3014                    self.src.push_str("break;\n}\n");
3015                }
3016                self.src.push_str("}\n");
3017            }
3018            abi::Instruction::VariantLift { variant, ty, .. } => {
3019                let blocks = self
3020                    .blocks
3021                    .drain(self.blocks.len() - variant.cases.len()..)
3022                    .collect::<Vec<_>>();
3023
3024                let ty = self
3025                    .r#gen
3026                    .type_name(&Type::Id(*ty), &self.namespace, Flavor::InStruct);
3027                let resultno = self.tmp();
3028                let result = format!("variant{resultno}");
3029
3030                let op0 = &operands[0];
3031
3032                // Use std::optional to avoid default constructor issues
3033                self.r#gen.r#gen.dependencies.needs_optional = true;
3034                uwriteln!(self.src, "std::optional<{ty}> {result}_opt;");
3035                uwriteln!(self.src, "switch ({op0}) {{");
3036                for (i, (case, (block, block_results))) in
3037                    variant.cases.iter().zip(blocks).enumerate()
3038                {
3039                    let tp = to_c_ident(&case.name).to_pascal_case();
3040                    uwriteln!(self.src, "case {i}: {{ {block}");
3041                    uwriteln!(
3042                        self.src,
3043                        "{result}_opt = {ty}{{{{{ty}::{tp}{{{}}}}}}};",
3044                        move_if_necessary(&block_results.first().cloned().unwrap_or_default())
3045                    );
3046                    uwriteln!(self.src, "}} break;");
3047                }
3048                uwriteln!(self.src, "}}");
3049                uwriteln!(self.src, "{ty} {result} = std::move(*{result}_opt);");
3050
3051                results.push(result);
3052            }
3053            abi::Instruction::EnumLower { .. } => results.push(format!("int32_t({})", operands[0])),
3054            abi::Instruction::EnumLift { ty, .. } => {
3055                let typename =
3056                    self.r#gen
3057                        .type_name(&Type::Id(*ty), &self.namespace, Flavor::InStruct);
3058                results.push(format!("({typename}){}", &operands[0]));
3059            }
3060            abi::Instruction::OptionLower {
3061                payload,
3062                results: result_types,
3063                ..
3064            } => {
3065                let (mut some, some_results) = self.blocks.pop().unwrap();
3066                let (mut none, none_results) = self.blocks.pop().unwrap();
3067                let some_payload = self.payloads.pop().unwrap();
3068                let _none_payload = self.payloads.pop().unwrap();
3069
3070                for (i, ty) in result_types.iter().enumerate() {
3071                    let tmp = self.tmp();
3072                    let name = self.tempname("option", tmp);
3073                    results.push(name.clone());
3074                    self.src.push_str(wit_bindgen_c::wasm_type(*ty));
3075                    self.src.push_str(" ");
3076                    self.src.push_str(&name);
3077                    self.src.push_str(";\n");
3078                    let some_result = &some_results[i];
3079                    uwriteln!(some, "{name} = {some_result};");
3080                    let none_result = &none_results[i];
3081                    uwriteln!(none, "{name} = {none_result};");
3082                }
3083
3084                let op0 = &operands[0];
3085                let flavor = if matches!(self.variant, AbiVariant::GuestImport) {
3086                    Flavor::BorrowedArgument
3087                } else {
3088                    Flavor::InStruct
3089                };
3090                let ty = self.r#gen.type_name(payload, &self.namespace, flavor);
3091                let is_function_param = self.params.iter().any(|p| p == op0);
3092                let value_extract = if matches!(payload, Type::String)
3093                    && matches!(self.variant, AbiVariant::GuestImport)
3094                    && !is_function_param
3095                {
3096                    // Import from struct/variant field: optional<wit::string> needs .get_view()
3097                    format!("(std::move({op0})).value().get_view()")
3098                } else {
3099                    // Direct parameter, export, or non-string: just .value()
3100                    format!("(std::move({op0})).value()")
3101                };
3102                let bind_some = format!("{ty} {some_payload} = {value_extract};");
3103
3104                uwrite!(
3105                    self.src,
3106                    "\
3107                    if (({op0}).has_value()) {{
3108                        {bind_some}
3109                        {some}}} else {{
3110                        {none}}}
3111                    "
3112                );
3113            }
3114            abi::Instruction::OptionLift { payload, .. } => {
3115                let (some, some_results) = self.blocks.pop().unwrap();
3116                let (_none, none_results) = self.blocks.pop().unwrap();
3117                assert!(none_results.is_empty());
3118                assert!(some_results.len() == 1);
3119                let flavor = if self.r#gen.r#gen.opts.api_style == APIStyle::Symmetric
3120                    && matches!(self.variant, AbiVariant::GuestExport)
3121                {
3122                    Flavor::BorrowedArgument
3123                } else {
3124                    Flavor::InStruct
3125                };
3126                let type_name = self.r#gen.type_name(payload, &self.namespace, flavor);
3127                let full_type = format!("std::optional<{type_name}>");
3128                let op0 = &operands[0];
3129
3130                let tmp = self.tmp();
3131                let resultname = self.tempname("option", tmp);
3132                let some_value = move_if_necessary(&some_results[0]);
3133                uwriteln!(
3134                    self.src,
3135                    "{full_type} {resultname};
3136                    if ({op0}) {{
3137                        {some}
3138                        {resultname}.emplace({some_value});
3139                    }}"
3140                );
3141                results.push(format!("std::move({resultname})"));
3142            }
3143            abi::Instruction::ResultLower {
3144                results: result_types,
3145                result,
3146                ..
3147            } => {
3148                let (mut err, err_results) = self.blocks.pop().unwrap();
3149                let (mut ok, ok_results) = self.blocks.pop().unwrap();
3150                let err_payload = self.payloads.pop().unwrap();
3151                let ok_payload = self.payloads.pop().unwrap();
3152
3153                for (i, ty) in result_types.iter().enumerate() {
3154                    let tmp = self.tmp();
3155                    let name = self.tempname("result", tmp);
3156                    results.push(name.clone());
3157                    self.src.push_str(wit_bindgen_c::wasm_type(*ty));
3158                    self.src.push_str(" ");
3159                    self.src.push_str(&name);
3160                    self.src.push_str(";\n");
3161                    let ok_result = &ok_results[i];
3162                    uwriteln!(ok, "{name} = {ok_result};");
3163                    let err_result = &err_results[i];
3164                    uwriteln!(err, "{name} = {err_result};");
3165                }
3166
3167                let op0 = &operands[0];
3168                let ok_ty = self.r#gen.optional_type_name(
3169                    result.ok.as_ref(),
3170                    &self.namespace,
3171                    Flavor::InStruct,
3172                );
3173                let err_ty = self.r#gen.optional_type_name(
3174                    result.err.as_ref(),
3175                    &self.namespace,
3176                    Flavor::InStruct,
3177                );
3178                let bind_ok = if let Some(_ok) = result.ok.as_ref() {
3179                    format!("{ok_ty} {ok_payload} = std::move({op0}).value();")
3180                } else {
3181                    String::new()
3182                };
3183                let bind_err = if let Some(_err) = result.err.as_ref() {
3184                    format!("{err_ty} {err_payload} = std::move({op0}).error();")
3185                } else {
3186                    String::new()
3187                };
3188
3189                uwrite!(
3190                    self.src,
3191                    "\
3192                    if (({op0}).has_value()) {{
3193                        {bind_ok}
3194                        {ok}}} else {{
3195                        {bind_err}
3196                        {err}}}
3197                    "
3198                );
3199            }
3200            abi::Instruction::ResultLift { result, .. } => {
3201                let (mut err, err_results) = self.blocks.pop().unwrap();
3202                let (mut ok, ok_results) = self.blocks.pop().unwrap();
3203                let mut ok_result = String::new();
3204                let err_result;
3205                if result.ok.is_none() {
3206                    ok.clear();
3207                } else {
3208                    ok_result = move_if_necessary(&ok_results[0]);
3209                }
3210                if result.err.is_none() {
3211                    err.clear();
3212                    self.r#gen.r#gen.dependencies.needs_wit = true;
3213                    err_result = String::from("wit::Void{}");
3214                } else {
3215                    err_result = move_if_necessary(&err_results[0]);
3216                }
3217                let ok_type = self.r#gen.optional_type_name(
3218                    result.ok.as_ref(),
3219                    &self.namespace,
3220                    Flavor::InStruct,
3221                );
3222                let err_type = result.err.as_ref().map_or(String::from("wit::Void"), |ty| {
3223                    self.r#gen.type_name(ty, &self.namespace, Flavor::InStruct)
3224                });
3225                let full_type = format!("std::expected<{ok_type}, {err_type}>",);
3226                let err_type = "std::unexpected";
3227                let operand = &operands[0];
3228
3229                let tmp = self.tmp();
3230                let resultname = self.tempname("result", tmp);
3231                // Use std::optional to avoid default constructor issues with std::expected
3232                self.r#gen.r#gen.dependencies.needs_optional = true;
3233                let ok_assign = if result.ok.is_some() {
3234                    format!("{resultname}_opt.emplace({full_type}({ok_result}));")
3235                } else {
3236                    format!("{resultname}_opt.emplace({full_type}());")
3237                };
3238                uwriteln!(
3239                    self.src,
3240                    "std::optional<{full_type}> {resultname}_opt;
3241                    if ({operand}==0) {{
3242                        {ok}
3243                        {ok_assign}
3244                    }} else {{
3245                        {err}
3246                        {resultname}_opt.emplace({err_type}{{{err_result}}});
3247                    }}
3248                    {full_type} {resultname} = std::move(*{resultname}_opt);"
3249                );
3250                results.push(resultname);
3251            }
3252            abi::Instruction::CallWasm { name, sig } => {
3253                let module_name = self
3254                    .r#gen
3255                    .wasm_import_module
3256                    .as_ref()
3257                    .map(|e| {
3258                        self.r#gen
3259                            .r#gen
3260                            .import_prefix
3261                            .as_ref()
3262                            .cloned()
3263                            .unwrap_or_default()
3264                            + e
3265                    })
3266                    .unwrap();
3267
3268                let func = self
3269                    .r#gen
3270                    .declare_import(&module_name, name, &sig.params, &sig.results);
3271
3272                // ... then call the function with all our operands
3273                if !sig.results.is_empty() {
3274                    self.src.push_str("auto ret = ");
3275                    results.push("ret".to_string());
3276                }
3277                self.src.push_str(&func);
3278                self.src.push_str("(");
3279                self.src.push_str(
3280                    &operands
3281                        .iter()
3282                        .map(|op| move_if_necessary(op))
3283                        .collect::<Vec<_>>()
3284                        .join(", "),
3285                );
3286                self.src.push_str(");\n");
3287            }
3288            abi::Instruction::CallInterface { func, .. } => {
3289                // dbg!(func);
3290                self.let_results(if func.result.is_some() { 1 } else { 0 }, results);
3291                let (namespace, func_name_h) = self.r#gen.func_namespace_name(func, true, true);
3292                if matches!(func.kind, FunctionKind::Method(_)) {
3293                    let this = operands.remove(0);
3294                    uwrite!(self.src, "({this}).get().");
3295                } else {
3296                    let mut relative = SourceWithState::default();
3297                    relative.qualify(&namespace);
3298                    self.push_str(&relative.src);
3299                }
3300                self.src.push_str(&func_name_h);
3301                self.push_str("(");
3302                self.push_str(
3303                    &operands
3304                        .iter()
3305                        .map(|op| move_if_necessary(op))
3306                        .collect::<Vec<_>>()
3307                        .join(", "),
3308                );
3309                self.push_str(");\n");
3310                if self.needs_dealloc {
3311                    uwriteln!(
3312                        self.src,
3313                        "for (auto i: _deallocate) {{ free(i); }}\n
3314                        _deallocate.clear();"
3315                    );
3316                }
3317            }
3318            abi::Instruction::Return { amt, func } => {
3319                match amt {
3320                    0 => {}
3321                    _ => {
3322                        assert!(*amt == operands.len());
3323                        // Fallible constructors return expected, not void
3324                        let is_fallible_constructor = self
3325                            .r#gen
3326                            .r#gen
3327                            .is_fallible_constructor(self.r#gen.resolve, func);
3328
3329                        match &func.kind {
3330                            FunctionKind::Constructor(_)
3331                                if self.r#gen.r#gen.opts.is_only_handle(self.variant)
3332                                    && !is_fallible_constructor =>
3333                            {
3334                                // strange but works
3335                                if matches!(self.variant, AbiVariant::GuestExport) {
3336                                    self.src.push_str("this->index = ");
3337                                } else {
3338                                    self.src.push_str("this->handle = ");
3339                                }
3340                            }
3341                            _ => self.src.push_str("return "),
3342                        }
3343                        if let Some(CabiPostInformation {
3344                            module: _,
3345                            name: _cabi_post_name,
3346                            ret_type: cabi_post_type,
3347                        }) = self.cabi_post.as_ref()
3348                        {
3349                            self.src.push_str("wit::guest_owned<");
3350                            self.src.push_str(cabi_post_type);
3351                            self.src.push_str(">(");
3352                        }
3353                        if *amt == 1 {
3354                            if operands[0].starts_with("std::move(") && !operands[0].contains('.') {
3355                                // remove the std::move due to return value optimization (and complex rules about when std::move harms)
3356                                self.src.push_str(&operands[0][9..]);
3357                            } else {
3358                                self.src.push_str(&operands[0]);
3359                            }
3360                        } else {
3361                            todo!();
3362                        }
3363                        if let Some(CabiPostInformation {
3364                            module: func_module,
3365                            name: func_name,
3366                            ret_type: _cabi_post_type,
3367                        }) = self.cabi_post.as_ref()
3368                        {
3369                            let cabi_post_name = self.r#gen.declare_import(
3370                                &format!("cabi_post_{func_module}"),
3371                                func_name,
3372                                &[WasmType::Pointer],
3373                                &[],
3374                            );
3375                            self.src.push_str(&format!(", ret, {cabi_post_name})"));
3376                        }
3377                        if matches!(func.kind, FunctionKind::Constructor(_))
3378                            && self.r#gen.r#gen.opts.is_only_handle(self.variant)
3379                            && !is_fallible_constructor
3380                        {
3381                            // we wrapped the handle in an object, so unpack it
3382
3383                            self.src.push_str(".into_handle()");
3384                        }
3385                        self.src.push_str(";\n");
3386                    }
3387                }
3388            }
3389            abi::Instruction::Malloc { .. } => todo!(),
3390            abi::Instruction::GuestDeallocate { .. } => {
3391                uwriteln!(self.src, "free((void*) ({}));", operands[0]);
3392            }
3393            abi::Instruction::GuestDeallocateString => {
3394                uwriteln!(self.src, "if (({}) > 0) {{", operands[1]);
3395                uwriteln!(
3396                    self.src,
3397                    "wit::string::drop_raw((void*) ({}));",
3398                    operands[0]
3399                );
3400                uwriteln!(self.src, "}}");
3401            }
3402            abi::Instruction::GuestDeallocateList { element } => {
3403                let (body, results) = self.blocks.pop().unwrap();
3404                assert!(results.is_empty());
3405                let tmp = self.tmp();
3406                let ptr = self.tempname("ptr", tmp);
3407                let len = self.tempname("len", tmp);
3408                uwriteln!(self.src, "uint8_t* {ptr} = {};", operands[0]);
3409                uwriteln!(self.src, "size_t {len} = {};", operands[1]);
3410                let i = self.tempname("i", tmp);
3411                uwriteln!(self.src, "for (size_t {i} = 0; {i} < {len}; {i}++) {{");
3412                let size = self.r#gen.sizes.size(element);
3413                uwriteln!(
3414                    self.src,
3415                    "uint8_t* base = {ptr} + {i} * {size};",
3416                    size = size.format(POINTER_SIZE_EXPRESSION)
3417                );
3418                uwriteln!(self.src, "(void) base;");
3419                uwrite!(self.src, "{body}");
3420                uwriteln!(self.src, "}}");
3421                uwriteln!(self.src, "if ({len} > 0) {{");
3422                uwriteln!(self.src, "free((void*) ({ptr}));");
3423                uwriteln!(self.src, "}}");
3424            }
3425            abi::Instruction::GuestDeallocateVariant { blocks } => {
3426                let blocks = self
3427                    .blocks
3428                    .drain(self.blocks.len() - blocks..)
3429                    .collect::<Vec<_>>();
3430
3431                uwriteln!(self.src, "switch ((int32_t) {}) {{", operands[0]);
3432                for (i, (block, results)) in blocks.into_iter().enumerate() {
3433                    assert!(results.is_empty());
3434                    uwriteln!(self.src, "case {}: {{", i);
3435                    self.src.push_str(&block);
3436                    self.src.push_str("break;\n}\n");
3437                }
3438                self.src.push_str("}\n");
3439            }
3440            abi::Instruction::PointerLoad { offset } => {
3441                let ptr_type = self.r#gen.r#gen.opts.ptr_type();
3442                self.load(ptr_type, *offset, operands, results)
3443            }
3444            abi::Instruction::LengthLoad { offset } => {
3445                self.load("size_t", *offset, operands, results)
3446            }
3447            abi::Instruction::PointerStore { offset } => {
3448                let ptr_type = self.r#gen.r#gen.opts.ptr_type();
3449                self.store(ptr_type, *offset, operands)
3450            }
3451            abi::Instruction::LengthStore { offset } => self.store("size_t", *offset, operands),
3452            abi::Instruction::FutureLower { .. } => todo!(),
3453            abi::Instruction::FutureLift { .. } => todo!(),
3454            abi::Instruction::StreamLower { .. } => todo!(),
3455            abi::Instruction::StreamLift { .. } => todo!(),
3456            abi::Instruction::ErrorContextLower { .. } => todo!(),
3457            abi::Instruction::ErrorContextLift { .. } => todo!(),
3458            abi::Instruction::Flush { amt } => {
3459                for i in operands.iter().take(*amt) {
3460                    let tmp = self.tmp();
3461                    let result = format!("result{tmp}");
3462                    uwriteln!(self.src, "auto {result} = {};", move_if_necessary(i));
3463                    results.push(result);
3464                }
3465            }
3466            abi::Instruction::AsyncTaskReturn { .. } => todo!(),
3467            abi::Instruction::DropHandle { .. } => todo!(),
3468        }
3469    }
3470
3471    fn return_pointer(&mut self, size: ArchitectureSize, align: Alignment) -> Self::Operand {
3472        // Track maximum return area requirements
3473        self.return_pointer_area_size = self.return_pointer_area_size.max(size);
3474        self.return_pointer_area_align = self.return_pointer_area_align.max(align);
3475
3476        // Generate pointer to shared ret_area
3477        let tmp = self.tmp();
3478        uwriteln!(
3479            self.src,
3480            "{} ptr{tmp} = ({0})(&ret_area);",
3481            self.r#gen.r#gen.opts.ptr_type(),
3482        );
3483
3484        format!("ptr{tmp}")
3485    }
3486
3487    fn push_block(&mut self) {
3488        let prev = core::mem::take(&mut self.src);
3489        self.block_storage.push(prev);
3490    }
3491
3492    fn finish_block(&mut self, operands: &mut Vec<Self::Operand>) {
3493        let to_restore = self.block_storage.pop().unwrap();
3494        let src = core::mem::replace(&mut self.src, to_restore);
3495        self.blocks.push((src.into(), core::mem::take(operands)));
3496    }
3497
3498    fn sizes(&self) -> &wit_bindgen_core::wit_parser::SizeAlign {
3499        &self.r#gen.sizes
3500    }
3501
3502    fn is_list_canonical(
3503        &self,
3504        resolve: &Resolve,
3505        ty: &wit_bindgen_core::wit_parser::Type,
3506    ) -> bool {
3507        if !resolve.all_bits_valid(ty) {
3508            return false;
3509        }
3510        match ty {
3511            Type::Id(id) => !self.r#gen.r#gen.types.get(*id).has_resource,
3512            _ => true,
3513        }
3514    }
3515}
3516
3517/// This describes the common ABI function referenced or implemented, the C++ side might correspond to a different type
3518enum SpecialMethod {
3519    None,
3520    ResourceDrop, // ([export]) [resource-drop]
3521    ResourceNew,  // [export][resource-new]
3522    ResourceRep,  // [export][resource-rep]
3523    Dtor,         // [dtor] (guest export only)
3524    Allocate,     // internal: allocate new object (called from generated code)
3525}
3526
3527fn is_special_method(func: &Function) -> SpecialMethod {
3528    if matches!(func.kind, FunctionKind::Static(_)) {
3529        if func.name.starts_with("[resource-drop]") {
3530            SpecialMethod::ResourceDrop
3531        } else if func.name.starts_with("[resource-new]") {
3532            SpecialMethod::ResourceNew
3533        } else if func.name.starts_with("[resource-rep]") {
3534            SpecialMethod::ResourceRep
3535        } else if func.name.starts_with("[dtor]") {
3536            SpecialMethod::Dtor
3537        } else if func.name == "$alloc" {
3538            SpecialMethod::Allocate
3539        } else {
3540            SpecialMethod::None
3541        }
3542    } else {
3543        SpecialMethod::None
3544    }
3545}