Support forward declarations for C-like languages

src/bindgen/bindings.rs

@@ -11,6 +11,8 @@ use std::io::{Read, Write};
 use std::path;
 use std::rc::Rc;
 
+use indexmap::IndexMap;
+
 use crate::bindgen::config::{Config, Language};
 use crate::bindgen::ir::{
     Constant, Function, ItemContainer, ItemMap, Path as BindgenPath, Static, Struct, Type, Typedef,
@@ -28,6 +30,7 @@ pub struct Bindings {
     struct_map: ItemMap<Struct>,
     typedef_map: ItemMap<Typedef>,
     struct_fileds_memo: RefCell<HashMap<BindgenPath, Rc<Vec<String>>>>,
+    pub forward_declarations: IndexMap<BindgenPath, Type>,
     pub globals: Vec<Static>,
     pub constants: Vec<Constant>,
     pub items: Vec<ItemContainer>,
@@ -45,6 +48,7 @@ impl Bindings {
         config: Config,
         struct_map: ItemMap<Struct>,
         typedef_map: ItemMap<Typedef>,
+        forward_declarations: IndexMap<BindgenPath, Type>,
         constants: Vec<Constant>,
         globals: Vec<Static>,
         items: Vec<ItemContainer>,
@@ -58,6 +62,7 @@ impl Bindings {
             struct_map,
             typedef_map,
             struct_fileds_memo: Default::default(),
+            forward_declarations,
             globals,
             constants,
             items,

src/bindgen/builder.rs

@@ -360,6 +360,7 @@ impl Builder {
                 Default::default(),
                 Default::default(),
                 Default::default(),
+                Default::default(),
                 true,
                 String::new(),
             ));

src/bindgen/config.rs

@@ -1076,6 +1076,16 @@ impl Default for Config {
 }
 
 impl Config {
+    pub(crate) fn forward_declarations_enabled(&self) -> bool {
+        match self.language {
+            Language::C | Language::Cxx => {
+                // Cannot generate forward declarations if `Style::Type` is specified.
+                self.style.generate_tag()
+            }
+            _ => false,
+        }
+    }
+
     pub(crate) fn cpp_compatible_c(&self) -> bool {
         self.language == Language::C && self.cpp_compat
     }

src/bindgen/ir/constant.rs

@@ -6,15 +6,16 @@ use std::borrow::Cow;
 use std::collections::HashMap;
 use std::io::Write;
 
+use indexmap::IndexSet;
 use syn::ext::IdentExt;
 use syn::UnOp;
 
 use crate::bindgen::config::{Config, Language};
 use crate::bindgen::declarationtyperesolver::DeclarationTypeResolver;
 use crate::bindgen::dependencies::Dependencies;
 use crate::bindgen::ir::{
-    AnnotationSet, Cfg, ConditionWrite, Documentation, GenericParams, Item, ItemContainer, Path,
-    Struct, ToCondition, Type,
+    AnnotationSet, Cfg, ConditionWrite, Documentation, GenericParams, GenericPath, Item,
+    ItemContainer, Path, Struct, ToCondition, Type,
 };
 use crate::bindgen::language_backend::LanguageBackend;
 use crate::bindgen::library::Library;
@@ -560,8 +561,13 @@ impl Item for Constant {
         &self.path
     }
 
-    fn add_dependencies(&self, library: &Library, out: &mut Dependencies) {
-        self.ty.add_dependencies(library, out);
+    fn add_dependencies(
+        &self,
+        library: &Library,
+        out: &mut Dependencies,
+        ptr_types: &mut IndexSet<GenericPath>,
+    ) {
+        self.ty.add_dependencies(library, out, ptr_types);
     }
 
     fn export_name(&self) -> &str {

src/bindgen/ir/enumeration.rs

@@ -4,6 +4,7 @@
 
 use std::io::Write;
 
+use indexmap::IndexSet;
 use syn::ext::IdentExt;
 
 use crate::bindgen::config::{Config, Language};
@@ -254,9 +255,14 @@ impl EnumVariant {
         }
     }
 
-    fn add_dependencies(&self, library: &Library, out: &mut Dependencies) {
+    fn add_dependencies(
+        &self,
+        library: &Library,
+        out: &mut Dependencies,
+        ptr_types: &mut IndexSet<GenericPath>,
+    ) {
         if let VariantBody::Body { ref body, .. } = self.body {
-            body.add_dependencies(library, out);
+            body.add_dependencies(library, out, ptr_types);
         }
     }
 
@@ -634,9 +640,14 @@ impl Item for Enum {
         out.insert_enum(library, self, monomorph, generic_values.to_owned());
     }
 
-    fn add_dependencies(&self, library: &Library, out: &mut Dependencies) {
+    fn add_dependencies(
+        &self,
+        library: &Library,
+        out: &mut Dependencies,
+        ptr_types: &mut IndexSet<GenericPath>,
+    ) {
         for variant in &self.variants {
-            variant.add_dependencies(library, out);
+            variant.add_dependencies(library, out, ptr_types);
         }
     }
 }

src/bindgen/ir/function.rs

@@ -4,6 +4,7 @@
 
 use std::collections::HashMap;
 
+use indexmap::IndexSet;
 use syn::ext::IdentExt;
 
 use crate::bindgen::config::{Config, Language};
@@ -122,10 +123,15 @@ impl Function {
         }
     }
 
-    pub fn add_dependencies(&self, library: &Library, out: &mut Dependencies) {
-        self.ret.add_dependencies(library, out);
+    pub fn add_dependencies(
+        &self,
+        library: &Library,
+        out: &mut Dependencies,
+        ptr_types: &mut IndexSet<GenericPath>,
+    ) {
+        self.ret.add_dependencies(library, out, ptr_types);
         for arg in &self.args {
-            arg.ty.add_dependencies(library, out);
+            arg.ty.add_dependencies(library, out, ptr_types);
         }
     }
 

src/bindgen/ir/global.rs

@@ -2,11 +2,13 @@
  * 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 indexmap::IndexSet;
+
 use crate::bindgen::config::Config;
 use crate::bindgen::declarationtyperesolver::DeclarationTypeResolver;
 use crate::bindgen::dependencies::Dependencies;
 use crate::bindgen::ir::{
-    AnnotationSet, Cfg, Documentation, GenericParams, Item, ItemContainer, Path, Type,
+    AnnotationSet, Cfg, Documentation, GenericParams, GenericPath, Item, ItemContainer, Path, Type,
 };
 use crate::bindgen::library::Library;
 
@@ -109,7 +111,12 @@ impl Item for Static {
         GenericParams::empty()
     }
 
-    fn add_dependencies(&self, library: &Library, out: &mut Dependencies) {
-        self.ty.add_dependencies(library, out);
+    fn add_dependencies(
+        &self,
+        library: &Library,
+        out: &mut Dependencies,
+        ptr_types: &mut IndexSet<GenericPath>,
+    ) {
+        self.ty.add_dependencies(library, out, ptr_types);
     }
 }

src/bindgen/ir/item.rs

@@ -2,15 +2,15 @@
  * 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 indexmap::IndexMap;
+use indexmap::{IndexMap, IndexSet};
 use std::mem;
 
 use crate::bindgen::config::Config;
 use crate::bindgen::declarationtyperesolver::DeclarationTypeResolver;
 use crate::bindgen::dependencies::Dependencies;
 use crate::bindgen::ir::{
-    AnnotationSet, Cfg, Constant, Documentation, Enum, GenericArgument, GenericParams, OpaqueItem,
-    Path, Static, Struct, Typedef, Union,
+    AnnotationSet, Cfg, Constant, Documentation, Enum, GenericArgument, GenericParams, GenericPath,
+    OpaqueItem, Path, Static, Struct, Typedef, Union,
 };
 use crate::bindgen::library::Library;
 use crate::bindgen::monomorph::Monomorphs;
@@ -44,7 +44,16 @@ pub trait Item {
     }
 
     fn rename_for_config(&mut self, _config: &Config) {}
-    fn add_dependencies(&self, _library: &Library, _out: &mut Dependencies) {}
+    fn add_dependencies(
+        &self,
+        _library: &Library,
+        _out: &mut Dependencies,
+        // IndexSet is used instead of HashSet in order to keep the insertion order.
+        // When running `cargo test`, //tests/expectations/* will be updated randomly
+        // if HashSet is used.
+        _ptr_types: &mut IndexSet<GenericPath>,
+    ) {
+    }
     fn instantiate_monomorph(
         &self,
         _generics: &[GenericArgument],

src/bindgen/ir/opaque.rs

@@ -2,11 +2,14 @@
  * 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 indexmap::IndexSet;
+
 use crate::bindgen::config::Config;
 use crate::bindgen::declarationtyperesolver::DeclarationTypeResolver;
 use crate::bindgen::dependencies::Dependencies;
 use crate::bindgen::ir::{
-    AnnotationSet, Cfg, Documentation, GenericArgument, GenericParams, Item, ItemContainer, Path,
+    AnnotationSet, Cfg, Documentation, GenericArgument, GenericParams, GenericPath, Item,
+    ItemContainer, Path,
 };
 use crate::bindgen::library::Library;
 use crate::bindgen::mangle;
@@ -98,7 +101,7 @@ impl Item for OpaqueItem {
         config.export.rename(&mut self.export_name);
     }
 
-    fn add_dependencies(&self, _: &Library, _: &mut Dependencies) {}
+    fn add_dependencies(&self, _: &Library, _: &mut Dependencies, _: &mut IndexSet<GenericPath>) {}
 
     fn instantiate_monomorph(
         &self,

src/bindgen/ir/structure.rs

@@ -4,14 +4,15 @@
 
 use std::io::Write;
 
+use indexmap::IndexSet;
 use syn::ext::IdentExt;
 
 use crate::bindgen::config::{Config, Language, LayoutConfig};
 use crate::bindgen::declarationtyperesolver::DeclarationTypeResolver;
 use crate::bindgen::dependencies::Dependencies;
 use crate::bindgen::ir::{
-    AnnotationSet, Cfg, Constant, Documentation, Field, GenericArgument, GenericParams, Item,
-    ItemContainer, Path, Repr, ReprAlign, ReprStyle, Type, Typedef,
+    AnnotationSet, Cfg, Constant, Documentation, Field, GenericArgument, GenericParams,
+    GenericPath, Item, ItemContainer, Path, Repr, ReprAlign, ReprStyle, Type, Typedef,
 };
 use crate::bindgen::library::Library;
 use crate::bindgen::mangle;
@@ -372,7 +373,12 @@ impl Item for Struct {
         }
     }
 
-    fn add_dependencies(&self, library: &Library, out: &mut Dependencies) {
+    fn add_dependencies(
+        &self,
+        library: &Library,
+        out: &mut Dependencies,
+        ptr_types: &mut IndexSet<GenericPath>,
+    ) {
         let mut fields = self.fields.iter();
 
         // If there is a tag field, skip it
@@ -381,13 +387,17 @@ impl Item for Struct {
         }
 
         for field in fields {
-            field
-                .ty
-                .add_dependencies_ignoring_generics(&self.generic_params, library, out);
+            field.ty.add_dependencies_ignoring_generics(
+                &self.generic_params,
+                library,
+                out,
+                ptr_types,
+                false,
+            );
         }
 
         for c in &self.associated_constants {
-            c.add_dependencies(library, out);
+            c.add_dependencies(library, out, ptr_types);
         }
     }