i_slint_compiler/

lib.rs

// Copyright © SixtyFPS GmbH <info@slint.dev>
// SPDX-License-Identifier: GPL-3.0-only OR LicenseRef-Slint-Royalty-free-2.0 OR LicenseRef-Slint-Software-3.0

// cSpell: ignore inlines namedreference pathutils
#![doc = include_str!("README.md")]
#![doc(html_logo_url = "https://slint.dev/logo/slint-logo-square-light.svg")]
#![cfg_attr(docsrs, feature(doc_cfg))]
// It would be nice to keep the compiler free of unsafe code
#![deny(unsafe_code)]

#[cfg(feature = "proc_macro_span")]
extern crate proc_macro;

use core::future::Future;
use core::pin::Pin;
use std::cell::RefCell;
use std::collections::HashMap;
use std::rc::Rc;

mod builtin_elements;
pub mod builtin_macros;
pub mod data_uri;
pub mod diagnostics;
pub mod embedded_resources;
pub mod expression_tree;
pub mod fileaccess;
pub mod generator;
pub mod langtype;
pub mod layout;
pub mod lexer;
pub mod literals;
pub mod llr;
pub mod lookup;
pub mod namedreference;
pub mod object_tree;
pub mod parser;
pub mod pathutils;
pub mod symbol_counters;
#[cfg(feature = "bundle-translations")]
pub mod translations;
pub mod typeloader;
pub mod typeregister;

pub mod passes;

use crate::generator::OutputFormat;
use std::path::Path;

/// Specify how the resources are embedded by the compiler
#[derive(Clone, Copy, Debug, Eq, PartialEq)]
pub enum EmbedResourcesKind {
    /// Embeds nothing (only useful for interpreter)
    Nothing,
    /// Only embed builtin resources (such as widget assets shipped with Slint).
    ///
    /// User resources are loaded from their absolute path at run-time.
    OnlyBuiltinResources,
    /// Don't embed resources, but list them in the Document as if they were embedded.
    ///
    /// Used by tools such as the LSP that need to know about all resources without embedding them.
    ListAllResources,
    /// Embed the content of all image resources in the binary as-is (a compressed PNG stays
    /// compressed), to be decoded at run-time.
    EmbedAllResources,
    #[cfg(feature = "renderer-software")]
    /// Pre-process images and fonts at compile time and embed them as uncompressed pixel data,
    /// ready to be drawn by the software renderer without any decoding at run-time.
    ///
    /// Useful for MCUs with no file system and little RAM.
    /// Only the Slint software renderer can use these resources; Skia and FemtoVG can't.
    EmbedTextures,
}

/// This enum specifies the default translation context when no context is explicitly
/// specified in the `@tr("context" => ...)` macro.
#[derive(Clone, Debug, Eq, PartialEq)]
#[non_exhaustive]
pub enum DefaultTranslationContext {
    /// The default translation context is the component name in which the `@tr` is written.
    ///
    /// This is the default behavior of `slint-tr-extractor`.
    ComponentName,
    /// Opt out of the default translation context.
    ///
    /// When using this option, invoke `slint-tr-extractor` with `--no-default-translation-context`
    /// to make sure that the translation files have no context for strings which didn't specify a context.
    None,
}

#[derive(Clone, Debug, Eq, PartialEq, Default)]
#[non_exhaustive]
pub enum ComponentSelection {
    /// All components that inherit from Window.
    ///
    /// Note: Components marked for export but lacking Window inheritance are not selected (this will produce a warning),
    /// For compatibility reason, the last exported component is still selected even if it doesn't inherit Window,
    /// and if no component is exported, the last component is selected
    #[default]
    ExportedWindows,

    /// The Last component (legacy for the viewer / interpreter)
    ///
    /// Only the last exported component is generated, regardless if this is a Window or not,
    /// (and it will be transformed in a Window)
    LastExported,

    /// The component with the given name is generated
    Named(String),
}

/// Type alias for the callback to open files mentioned in `import` statements
///
/// This is a dyn-compatible version of:
///
/// ```ignore
/// async fn(String) -> Option<std::io::Result<String>>
/// ```
///
/// Unfortunately AsyncFn is not dyn-compatible yet.
pub type OpenImportCallback =
    Rc<dyn Fn(String) -> Pin<Box<dyn Future<Output = Option<std::io::Result<String>>>>>>;
pub type ResourceUrlMapper =
    Rc<dyn Fn(&url::Url) -> Pin<Box<dyn Future<Output = Option<url::Url>>>>>;

/// CompilationConfiguration allows configuring different aspects of the compiler.
#[derive(Clone)]
pub struct CompilerConfiguration {
    /// Indicate whether to embed resources such as images in the generated output or whether
    /// to retain references to the resources on the file system.
    pub embed_resources: EmbedResourcesKind,
    /// Whether to use SDF when pre-rendering fonts.
    #[cfg(all(feature = "renderer-software", feature = "sdf-fonts"))]
    pub use_sdf_fonts: bool,
    /// The compiler will look in these paths for components used in the file to compile.
    pub include_paths: Vec<std::path::PathBuf>,
    /// The compiler will look in these paths for library imports.
    pub library_paths: HashMap<String, std::path::PathBuf>,
    /// the name of the style. (eg: "native")
    pub style: Option<String>,

    /// Callback to load import files
    ///
    /// The callback should open the file specified by the given file name and
    /// return a future that provides the text content of the file as output.
    pub open_import_callback: Option<OpenImportCallback>,
    /// Callback to map URLs for resources
    ///
    /// The function takes the url and returns the mapped URL (or None if not mapped)
    pub resource_url_mapper: Option<ResourceUrlMapper>,

    /// Run the pass that inlines all the elements.
    ///
    /// This may help optimization to optimize the runtime resources usages,
    /// but at the cost of much more generated code and binary size.
    pub inline_all_elements: bool,

    /// Compile time scale factor to apply to embedded resources such as images and glyphs.
    /// It will also be set as a const scale factor on the `slint::Window`.
    pub const_scale_factor: Option<f32>,

    /// Whether image sizes are known when a compiled component is instantiated.
    /// This is false when the generated code may run on the web, where the browser
    /// decodes images asynchronously and the size updates once an image is loaded,
    /// so that expressions using an image size stay in bindings.
    pub const_image_sizes: bool,

    /// expose the accessible role and properties
    pub accessibility: bool,

    /// Add support for experimental features
    pub enable_experimental: bool,

    /// The domain used as one of the parameter to the translate function
    pub translation_domain: Option<String>,
    /// When Some, this is the path where the translations are looked at to bundle the translations
    #[cfg(feature = "bundle-translations")]
    pub translation_path_bundle: Option<std::path::PathBuf>,
    /// Default translation context
    pub default_translation_context: DefaultTranslationContext,

    /// Do not generate the hook to create native menus
    pub no_native_menu: bool,

    /// C++ namespace
    pub cpp_namespace: Option<String>,

    /// When true, fail the build when a binding loop is detected with a window layout property
    /// (otherwise this is a compatibility warning)
    pub error_on_binding_loop_with_window_layout: bool,

    /// Generate debug information for elements (ids, type names)
    pub debug_info: bool,

    /// Write, next to the generated code, the map of its coverage points of
    /// the `.slint` source, for `slint-sc-coverage`. Only the Slint SC
    /// generator honors it, and only when writing to a file.
    pub coverage: bool,

    /// Generate debug hooks to inspect/override properties.
    pub debug_hooks: Option<std::hash::RandomState>,

    pub components_to_generate: ComponentSelection,

    /// The name of the library when compiling as a library.
    pub library_name: Option<String>,

    /// Specify the Rust module to place the generated code in.
    pub rust_module: Option<String>,

    /// Set automatically when the output format is `SlintSc`.
    /// The compiler rejects all features not supported by the
    /// safety-critical subset.
    #[cfg(feature = "slint-sc")]
    pub(crate) slint_sc: bool,

    /// Set by tools such as `slint-viewer`, the LSP (editor diagnostics/preview), and the
    /// live-reload runtime to indicate that the `.slint` file is being previewed rather than
    /// driven by real host application logic.
    pub is_preview: bool,
}

impl CompilerConfiguration {
    pub fn new(output_format: OutputFormat) -> Self {
        let embed_resources = if std::env::var_os("SLINT_EMBED_TEXTURES").is_some()
            || std::env::var_os("DEP_MCU_BOARD_SUPPORT_MCU_EMBED_TEXTURES").is_some()
        {
            #[cfg(not(feature = "renderer-software"))]
            panic!(
                "the renderer-software feature must be enabled in i-slint-compiler when embedding textures"
            );
            #[cfg(feature = "renderer-software")]
            EmbedResourcesKind::EmbedTextures
        } else if let Ok(var) = std::env::var("SLINT_EMBED_RESOURCES") {
            let var = var.parse::<bool>().unwrap_or_else(|_|{
                panic!("SLINT_EMBED_RESOURCES has incorrect value. Must be either unset, 'true' or 'false'")
            });
            match var {
                true => EmbedResourcesKind::EmbedAllResources,
                false => EmbedResourcesKind::OnlyBuiltinResources,
            }
        } else {
            match output_format {
                #[cfg(feature = "rust")]
                OutputFormat::Rust => EmbedResourcesKind::EmbedAllResources,
                OutputFormat::Interpreter => EmbedResourcesKind::Nothing,
                _ => EmbedResourcesKind::OnlyBuiltinResources,
            }
        };

        let inline_all_elements = match std::env::var("SLINT_INLINING") {
            Ok(var) => var.parse::<bool>().unwrap_or_else(|_| {
                panic!(
                    "SLINT_INLINING has incorrect value. Must be either unset, 'true' or 'false'"
                )
            }),
            // Currently, the interpreter needs the inlining to be on.
            Err(_) => output_format == OutputFormat::Interpreter,
        };

        // The Slint SC generator flattens the exported component's element
        // tree, so user-defined components must be inlined away. This
        // overrides a SLINT_INLINING=false env override.
        #[cfg(feature = "slint-sc")]
        let inline_all_elements =
            inline_all_elements || matches!(output_format, OutputFormat::SlintSc);

        let const_scale_factor = std::env::var("SLINT_SCALE_FACTOR")
            .ok()
            .and_then(|x| x.parse::<f32>().ok())
            .filter(|f| *f > 0.);

        let const_image_sizes = match std::env::var("CARGO_CFG_TARGET_FAMILY") {
            // Set by cargo when running in a build script (slint-build): the target is known.
            Ok(target_family) => !target_family.split(',').any(|f| f == "wasm"),
            // The target is unknown (slint! macro, C++). The interpreter compiles for the
            // architecture it runs on; otherwise assume the code may run on the web.
            Err(_) => output_format == OutputFormat::Interpreter && !cfg!(target_family = "wasm"),
        };

        let enable_experimental = std::env::var_os("SLINT_ENABLE_EXPERIMENTAL_FEATURES").is_some();

        let debug_info = std::env::var_os("SLINT_EMIT_DEBUG_INFO").is_some();

        #[cfg(feature = "slint-sc")]
        let slint_sc = matches!(output_format, OutputFormat::SlintSc);

        let cpp_namespace = match output_format {
            #[cfg(feature = "cpp")]
            OutputFormat::Cpp(config) => match config.namespace {
                Some(namespace) => Some(namespace),
                None => std::env::var("SLINT_CPP_NAMESPACE").ok(),
            },
            _ => None,
        };

        let style = std::env::var("SLINT_STYLE").ok();

        Self {
            embed_resources,
            include_paths: Default::default(),
            library_paths: Default::default(),
            style,
            open_import_callback: None,
            resource_url_mapper: None,
            inline_all_elements,
            const_scale_factor,
            const_image_sizes,
            accessibility: true,
            enable_experimental,
            translation_domain: None,
            default_translation_context: DefaultTranslationContext::ComponentName,
            no_native_menu: false,
            cpp_namespace,
            error_on_binding_loop_with_window_layout: false,
            debug_info,
            coverage: false,
            debug_hooks: None,
            components_to_generate: ComponentSelection::ExportedWindows,
            #[cfg(all(feature = "renderer-software", feature = "sdf-fonts"))]
            use_sdf_fonts: false,
            #[cfg(feature = "bundle-translations")]
            translation_path_bundle: std::env::var("SLINT_BUNDLE_TRANSLATIONS")
                .ok()
                .map(|x| x.into()),
            library_name: None,
            rust_module: None,
            #[cfg(feature = "slint-sc")]
            slint_sc,
            is_preview: false,
        }
    }
}

/// Prepare for compilation of the source file
/// - storing parser configuration
/// - setting up the parser
fn prepare_for_compile(
    diagnostics: &mut diagnostics::BuildDiagnostics,
    #[allow(unused_mut)] mut compiler_config: CompilerConfiguration,
) -> typeloader::TypeLoader {
    #[cfg(feature = "renderer-software")]
    if compiler_config.embed_resources == EmbedResourcesKind::EmbedTextures {
        // HACK: disable accessibility when compiling for the software renderer
        // accessibility is not supported with backend that support software renderer anyway
        compiler_config.accessibility = false;
    }

    diagnostics.enable_experimental = compiler_config.enable_experimental;
    #[cfg(feature = "slint-sc")]
    {
        diagnostics.slint_sc = compiler_config.slint_sc;
    }

    typeloader::TypeLoader::new(compiler_config, diagnostics)
}

pub async fn compile_syntax_node(
    doc_node: parser::SyntaxNode,
    mut diagnostics: diagnostics::BuildDiagnostics,
    #[allow(unused_mut)] mut compiler_config: CompilerConfiguration,
) -> (object_tree::Document, diagnostics::BuildDiagnostics, typeloader::TypeLoader) {
    let mut loader = prepare_for_compile(&mut diagnostics, compiler_config);

    let doc_node: parser::syntax_nodes::Document = doc_node.into();

    let type_registry =
        Rc::new(RefCell::new(typeregister::TypeRegister::new(&loader.global_type_registry)));
    let (foreign_imports, reexports) =
        loader.load_dependencies_recursively(&doc_node, &mut diagnostics, &type_registry).await;

    let ignore_missing_font_files = loader.compiler_config.resource_url_mapper.is_some();
    let mut doc = crate::object_tree::Document::from_node(
        doc_node,
        foreign_imports,
        reexports,
        &mut diagnostics,
        &type_registry,
        ignore_missing_font_files,
        &loader.symbol_counters,
    );

    if !diagnostics.has_errors() {
        passes::run_passes(&mut doc, &mut loader, false, &mut diagnostics).await;
    } else {
        // Don't run all the passes in case of errors because because some invariants are not met.
        passes::run_import_passes(&doc, &loader, &mut diagnostics);
    }
    (doc, diagnostics, loader)
}

/// Pass a file to the compiler and process it fully, applying all the
/// necessary compilation passes.
///
/// This returns a `Tuple` containing the actual cleaned `path` to the file,
/// a set of `BuildDiagnostics` and a `TypeLoader` with all compilation passes applied.
pub async fn load_root_file(
    path: &Path,
    source_path: &Path,
    source_code: String,
    mut diagnostics: diagnostics::BuildDiagnostics,
    #[allow(unused_mut)] mut compiler_config: CompilerConfiguration,
) -> (std::path::PathBuf, diagnostics::BuildDiagnostics, typeloader::TypeLoader) {
    let mut loader = prepare_for_compile(&mut diagnostics, compiler_config);

    let (path, _) =
        loader.load_root_file(path, source_path, source_code, false, &mut diagnostics).await;

    (path, diagnostics, loader)
}

/// Pass a file to the compiler and process it fully, applying all the
/// necessary compilation passes, just like `load_root_file`.
///
/// This returns a `Tuple` containing the actual cleaned `path` to the file,
/// a set of `BuildDiagnostics`, a `TypeLoader` with all compilation passes
/// applied and another `TypeLoader` with a minimal set of passes applied to it.
pub async fn load_root_file_with_raw_type_loader(
    path: &Path,
    source_path: &Path,
    source_code: String,
    mut diagnostics: diagnostics::BuildDiagnostics,
    #[allow(unused_mut)] mut compiler_config: CompilerConfiguration,
) -> (
    std::path::PathBuf,
    diagnostics::BuildDiagnostics,
    typeloader::TypeLoader,
    Option<typeloader::TypeLoader>,
) {
    let mut loader = prepare_for_compile(&mut diagnostics, compiler_config);

    let (path, raw_type_loader) =
        loader.load_root_file(path, source_path, source_code, true, &mut diagnostics).await;

    (path, diagnostics, loader, raw_type_loader)
}

/// Returns true and emits an error if experimental features should be disabled.
///
/// Some experimental features are used internally which is why this function also checks
/// `TypeRegister::expose_internal_types`.
fn reject_experimental_feature(
    diagnostics: &mut diagnostics::BuildDiagnostics,
    type_register: &typeregister::TypeRegister,
    feature: &str,
    source: &dyn diagnostics::Spanned,
) -> bool {
    if !diagnostics.enable_experimental && !type_register.expose_internal_types {
        diagnostics.push_error(format!("'{feature}' is an experimental feature"), source);
        true
    } else {
        false
    }
}