nbindgen 0.0.1

/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

use std::io::Write;

use syn;

use crate::bindgen::config::{Config, LayoutConfig};
use crate::bindgen::dependencies::Dependencies;
use crate::bindgen::ir::{
    AnnotationSet, Cfg, ConditionWrite, Constant, Documentation, GenericParams, Item,
    ItemContainer, Path, Repr, ReprAlign, ReprStyle, ToCondition, Type, Typedef,
};
use crate::bindgen::library::Library;
use crate::bindgen::rename::{IdentifierType, RenameRule};
use crate::bindgen::reserved;
use crate::bindgen::utilities::{find_first_some, IterHelpers};
use crate::bindgen::writer::{ListType, Source, SourceWriter};

#[derive(Debug, Clone)]
pub struct Struct {
    pub path: Path,
    pub export_name: String,
    pub generic_params: GenericParams,
    pub fields: Vec<(String, Type, Documentation)>,
    /// Whether there's a tag field on the body of this struct. When this is
    /// true, is_enum_variant_body is also guaranteed to be true.
    pub is_tagged: bool,
    /// Whether this is an enum variant body.
    pub is_enum_variant_body: bool,
    pub alignment: Option<ReprAlign>,
    pub is_transparent: bool,
    pub tuple_struct: bool,
    pub cfg: Option<Cfg>,
    pub annotations: AnnotationSet,
    pub documentation: Documentation,
    pub associated_constants: Vec<Constant>,
}

impl Struct {
    pub fn add_associated_constant(&mut self, c: Constant) {
        self.associated_constants.push(c);
    }

    pub fn load(
        layout_config: &LayoutConfig,
        item: &syn::ItemStruct,
        mod_cfg: Option<&Cfg>,
    ) -> Result<Self, String> {
        let repr = Repr::load(&item.attrs)?;
        let is_transparent = match repr.style {
            ReprStyle::C => false,
            ReprStyle::Transparent => true,
            _ => {
                return Err("Struct is not marked #[repr(C)] or #[repr(transparent)].".to_owned());
            }
        };

        // Ensure we can safely represent the struct given the configuration.
        if let Some(align) = repr.align {
            layout_config.ensure_safe_to_represent(&align)?;
        }

        let (fields, tuple_struct) = match item.fields {
            syn::Fields::Unit => (Vec::new(), false),
            syn::Fields::Named(ref fields) => {
                let out = fields
                    .named
                    .iter()
                    .try_skip_map(|x| x.as_ident_and_type())?;
                (out, false)
            }
            syn::Fields::Unnamed(ref fields) => {
                let mut out = Vec::new();
                let mut current = 0;
                for field in fields.unnamed.iter() {
                    if let Some(x) = Type::load(&field.ty)? {
                        out.push((format!("{}", current), x, Documentation::load(&field.attrs)));
                        current += 1;
                    }
                }
                (out, true)
            }
        };

        let is_tagged = false;
        let is_enum_variant_body = false;

        Ok(Struct::new(
            Path::new(item.ident.to_string()),
            GenericParams::new(&item.generics),
            fields,
            is_tagged,
            is_enum_variant_body,
            repr.align,
            is_transparent,
            tuple_struct,
            Cfg::append(mod_cfg, Cfg::load(&item.attrs)),
            AnnotationSet::load(&item.attrs)?,
            Documentation::load(&item.attrs),
        ))
    }

    pub fn new(
        path: Path,
        generic_params: GenericParams,
        fields: Vec<(String, Type, Documentation)>,
        is_tagged: bool,
        is_enum_variant_body: bool,
        alignment: Option<ReprAlign>,
        is_transparent: bool,
        tuple_struct: bool,
        cfg: Option<Cfg>,
        annotations: AnnotationSet,
        documentation: Documentation,
    ) -> Self {
        let export_name = path.name().to_owned();
        Self {
            path,
            export_name,
            generic_params,
            fields,
            is_tagged,
            is_enum_variant_body,
            alignment,
            is_transparent,
            tuple_struct,
            cfg,
            annotations,
            documentation,
            associated_constants: vec![],
        }
    }

    pub fn simplify_standard_types(&mut self) {
        for &mut (_, ref mut ty, _) in &mut self.fields {
            ty.simplify_standard_types();
        }
    }

    pub fn is_generic(&self) -> bool {
        self.generic_params.len() > 0
    }
}

impl Item for Struct {
    fn path(&self) -> &Path {
        &self.path
    }

    fn export_name(&self) -> &str {
        &self.export_name
    }

    fn cfg(&self) -> Option<&Cfg> {
        self.cfg.as_ref()
    }

    fn annotations(&self) -> &AnnotationSet {
        &self.annotations
    }

    fn annotations_mut(&mut self) -> &mut AnnotationSet {
        &mut self.annotations
    }

    fn container(&self) -> ItemContainer {
        ItemContainer::Struct(self.clone())
    }

    fn rename_for_config(&mut self, config: &Config) {
        // Rename the name of the struct
        if !self.is_tagged {
            config.export.rename(&mut self.export_name);
        }

        // Rename the types used in fields
        {
            let fields = self
                .fields
                .iter_mut()
                .skip(if self.is_tagged { 1 } else { 0 });
            for &mut (_, ref mut ty, _) in fields {
                ty.rename_for_config(config, &self.generic_params);
            }
        }

        // Apply renaming rules to fields in the following order
        //   1. `cbindgen::field-names` annotation
        //   2. `cbindgen::rename-all` annotation
        //   3. config struct rename rule
        // If the struct is a tuple struct and we have not renamed the
        // fields, then prefix each of them with an underscore.
        // If any field is a reserved keyword, then postfix it with an
        // underscore.

        // Scope for mutable borrow of fields
        {
            let mut names = self.fields.iter_mut().map(|field| &mut field.0);

            let field_rules = [
                self.annotations.parse_atom::<RenameRule>("rename-all"),
                config.structure.rename_fields,
            ];

            if let Some(o) = self.annotations.list("field-names") {
                for (dest, src) in names.zip(o) {
                    *dest = src;
                }
            } else if let Some(r) = find_first_some(&field_rules) {
                for name in names {
                    *name = r.apply_to_snake_case(name, IdentifierType::StructMember);
                }
            } else if self.tuple_struct {
                // If there is a tag field, skip it
                if self.is_tagged {
                    names.next();
                }

                // If we don't have any rules for a tuple struct, prefix them with
                // an underscore so it still compiles
                for name in names {
                    name.insert(0, 'x');
                }
            }
        }

        for field in &mut self.fields {
            reserved::escape(&mut field.0);
        }

        for c in self.associated_constants.iter_mut() {
            c.rename_for_config(config);
        }
    }

    fn add_dependencies(&self, library: &Library, out: &mut Dependencies) {
        let mut fields = self.fields.iter();

        // If there is a tag field, skip it
        if self.is_tagged {
            fields.next();
        }

        for &(_, ref ty, _) in fields {
            ty.add_dependencies_ignoring_generics(&self.generic_params, library, out);
        }

        for c in &self.associated_constants {
            c.add_dependencies(library, out);
        }
    }
}

impl Source for Struct {
    fn write<F: Write>(&self, config: &Config, out: &mut SourceWriter<F>) {
        if self.is_transparent {
            let typedef = Typedef {
                path: self.path.clone(),
                export_name: self.export_name.to_owned(),
                generic_params: self.generic_params.clone(),
                aliased: self.fields[0].1.clone(),
                cfg: self.cfg.clone(),
                annotations: self.annotations.clone(),
                documentation: self.documentation.clone(),
            };
            typedef.write(config, out);
            for constant in &self.associated_constants {
                out.new_line();
                constant.write(config, out, Some(self));
            }
            return;
        }

        let condition = (&self.cfg).to_condition(config);
        condition.write_before(config, out);

        self.documentation.write(config, out);

        /*
        if let Some(align) = self.alignment {
            match align {
                ReprAlign::Packed => {
                    if let Some(ref anno) = config.layout.packed {
                        write!(out, "{}", anno);
                    }
                }
                ReprAlign::Align(n) => {
                    if let Some(ref anno) = config.layout.aligned_n {
                        write!(out, "{}({})", anno, n);
                    }
                }
            }
        }
        */
        if self.annotations.must_use {
            if let Some(ref anno) = config.structure.must_use {
                write!(out, " {}", anno);
            }
        }

        write!(out, "type {}*", self.export_name());
        if !self.is_enum_variant_body {
            self.generic_params.write(config, out);
        }

        out.write(" = object");
        out.new_line();
        out.indent();

        if config.documentation {
            out.write_vertical_source_list(&self.fields, ListType::Cap(""));
        } else {
            let vec: Vec<_> = self
                .fields
                .iter()
                .map(|&(ref name, ref ty, _)| (name.clone(), ty.clone()))
                .collect();
            out.write_vertical_source_list(&vec[..], ListType::Cap(""));
        }

        if let Some(body) = config.export.extra_body(&self.path) {
            out.write_raw_block(body);
        }

        out.dedent();

        for constant in &self.associated_constants {
            out.new_line();
            constant.write(config, out, Some(self));
        }

        condition.write_after(config, out);
    }
}

pub trait SynFieldHelpers {
    fn as_ident_and_type(&self) -> Result<Option<(String, Type, Documentation)>, String>;
}

impl SynFieldHelpers for syn::Field {
    fn as_ident_and_type(&self) -> Result<Option<(String, Type, Documentation)>, String> {
        let ident = self
            .ident
            .as_ref()
            .ok_or_else(|| "field is missing identifier".to_string())?
            .clone();
        let converted_ty = Type::load(&self.ty)?;

        if let Some(x) = converted_ty {
            Ok(Some((
                ident.to_string(),
                x,
                Documentation::load(&self.attrs),
            )))
        } else {
            Ok(None)
        }
    }
}