expose discovered composite types and aliases to parse callbacks

bindgen/callbacks.rs

@@ -159,6 +159,54 @@ pub trait ParseCallbacks: fmt::Debug {
     fn wrap_as_variadic_fn(&self, _name: &str) -> Option<String> {
         None
     }
+
+    /// This will get called everytime an item (currently struct, union, and alias) is found with some information about it
+    fn new_item_found(&self, _id: DiscoveredItemId, _item: DiscoveredItem) {}
+
+    // TODO add callback for ResolvedTypeRef
+}
+
+/// An identifier for a discovered item. Used to identify an aliased type (see [DiscoveredItem::Alias])
+#[derive(Ord, PartialOrd, PartialEq, Eq, Hash, Debug, Clone, Copy)]
+pub struct DiscoveredItemId(pub(crate) usize);
+
+/// Struct passed to [ParseCallbacks::new_item_found] containing information about discovered
+/// items (struct, union, and alias)
+pub enum DiscoveredItem<'a> {
+    /// Represents a struct with its original name in C and its generated binding name
+    Struct {
+        /// The original name (learnt from C) of the structure
+        /// Can be None if the union is anonymous.
+        original_name: Option<&'a str>,
+
+        /// The name of the generated binding
+        final_name: String,
+    },
+
+    /// Represents a union with its original name in C and its generated binding name
+    Union {
+        /// The original name (learnt from C) of the structure.
+        /// Can be None if the union is anonymous.
+        original_name: Option<&'a str>,
+
+        /// The name of the generated binding
+        final_name: String,
+    },
+
+    /// Represents an alias like a typedef
+    /// ```c
+    ///     typedef struct MyStruct {
+    ///         ...
+    ///     } StructAlias;
+    /// ```
+    /// Here, the name of the alias is `StructAlias` and it's an alias for `struct MyStruct`
+    Alias {
+        /// The name of the alias in C (`StructAlias`)
+        alias_name: String,
+
+        /// The identifier of the discovered type
+        alias_for: DiscoveredItemId,
+    }, // functions, modules, etc.
 }
 
 /// Relevant information about a type to which new derive attributes will be added using

bindgen/codegen/mod.rs

@@ -20,7 +20,10 @@ use self::struct_layout::StructLayoutTracker;
 
 use super::BindgenOptions;
 
-use crate::callbacks::{DeriveInfo, FieldInfo, TypeKind as DeriveTypeKind};
+use crate::callbacks::{
+    DeriveInfo, DiscoveredItem, DiscoveredItemId, FieldInfo,
+    TypeKind as DeriveTypeKind,
+};
 use crate::codegen::error::Error;
 use crate::ir::analysis::{HasVtable, Sizedness};
 use crate::ir::annotations::{
@@ -967,6 +970,18 @@ impl CodeGenerator for Type {
 
                 let rust_name = ctx.rust_ident(&name);
 
+                ctx.options().for_each_callback(|cb| {
+                    cb.new_item_found(
+                        DiscoveredItemId(item.id().as_usize()),
+                        DiscoveredItem::Alias {
+                            alias_name: rust_name.to_string(),
+                            alias_for: DiscoveredItemId(
+                                inner_item.id().as_usize(),
+                            ),
+                        },
+                    );
+                });
+
                 let mut tokens = if let Some(comment) = item.comment(ctx) {
                     attributes::doc(comment)
                 } else {
@@ -2252,6 +2267,24 @@ impl CodeGenerator for CompInfo {
 
         let is_rust_union = is_union && struct_layout.is_rust_union();
 
+        ctx.options().for_each_callback(|cb| {
+            let discovered_item = match self.kind() {
+                CompKind::Struct => DiscoveredItem::Struct {
+                    original_name: item.kind().expect_type().name(),
+                    final_name: canonical_ident.to_string(),
+                },
+                CompKind::Union => DiscoveredItem::Union {
+                    original_name: item.kind().expect_type().name(),
+                    final_name: canonical_ident.to_string(),
+                },
+            };
+
+            cb.new_item_found(
+                DiscoveredItemId(item.id().as_usize()),
+                discovered_item,
+            );
+        });
+
         // The custom derives callback may return a list of derive attributes;
         // add them to the end of the list.
         let custom_derives = ctx.options().all_callbacks(|cb| {