Auto merge of #491 - fitzgen:template-instantiation, r=emilio

Template instantiation

I very much suspect this needs a rebase, but I haven't done it yet.

This is the majority of #446, although it doesn't have the name generation for anonymous named types patches yet (that will be a different PR).

Author: bors-servo

src/clang.rs

@@ -136,11 +136,11 @@ impl Cursor {
         // `clang_Cursor_getNumTemplateArguments` is totally unreliable.
         // Therefore, try former first, and only fallback to the latter if we
         // have to.
-        self.cur_type().num_template_args()
+        self.cur_type()
+            .num_template_args()
             .or_else(|| {
-                let n: c_int = unsafe {
-                    clang_Cursor_getNumTemplateArguments(self.x)
-                };
+                let n: c_int =
+                    unsafe { clang_Cursor_getNumTemplateArguments(self.x) };
 
                 if n >= 0 {
                     Some(n as u32)
@@ -360,6 +360,41 @@ impl Cursor {
         }
     }
 
+    /// Collect all of this cursor's children into a vec and return them.
+    pub fn collect_children(&self) -> Vec<Cursor> {
+        let mut children = vec![];
+        self.visit(|c| {
+            children.push(c);
+            CXChildVisit_Continue
+        });
+        children
+    }
+
+    /// Does this cursor have any children?
+    pub fn has_children(&self) -> bool {
+        let mut has_children = false;
+        self.visit(|_| {
+            has_children = true;
+            CXChildVisit_Break
+        });
+        has_children
+    }
+
+    /// Does this cursor have at least `n` children?
+    pub fn has_at_least_num_children(&self, n: usize) -> bool {
+        assert!(n > 0);
+        let mut num_left = n;
+        self.visit(|_| {
+            num_left -= 1;
+            if num_left == 0 {
+                CXChildVisit_Break
+            } else {
+                CXChildVisit_Continue
+            }
+        });
+        num_left == 0
+    }
+
     /// Returns whether the given location contains a cursor with the given
     /// kind in the first level of nesting underneath (doesn't look
     /// recursively).
@@ -581,7 +616,7 @@ impl Hash for Cursor {
 }
 
 /// The type of a node in clang's AST.
-#[derive(Clone)]
+#[derive(Clone, Copy)]
 pub struct Type {
     x: CXType,
 }
@@ -657,6 +692,31 @@ impl Type {
         }
     }
 
+    /// Get the canonical declaration of this type, if it is available.
+    pub fn canonical_declaration(&self,
+                                 location: Option<&Cursor>)
+                                 -> Option<CanonicalTypeDeclaration> {
+        let mut declaration = self.declaration();
+        if !declaration.is_valid() {
+            if let Some(location) = location {
+                let mut location = *location;
+                if let Some(referenced) = location.referenced() {
+                    location = referenced;
+                }
+                if location.is_template_like() {
+                    declaration = location;
+                }
+            }
+        }
+
+        let canonical = declaration.canonical();
+        if canonical.is_valid() && canonical.kind() != CXCursor_NoDeclFound {
+            Some(CanonicalTypeDeclaration(*self, canonical))
+        } else {
+            None
+        }
+    }
+
     /// Get a raw display name for this type.
     pub fn spelling(&self) -> String {
         unsafe { cxstring_into_string(clang_getTypeSpelling(self.x)) }
@@ -731,10 +791,12 @@ impl Type {
     /// If this type is a class template specialization, return its
     /// template arguments. Otherwise, return None.
     pub fn template_args(&self) -> Option<TypeTemplateArgIterator> {
-        self.num_template_args().map(|n| TypeTemplateArgIterator {
-            x: self.x,
-            length: n,
-            index: 0,
+        self.num_template_args().map(|n| {
+            TypeTemplateArgIterator {
+                x: self.x,
+                length: n,
+                index: 0,
+            }
         })
     }
 
@@ -836,9 +898,8 @@ impl Type {
         // Yep, the spelling of this containing type-parameter is extremely
         // nasty... But can happen in <type_traits>. Unfortunately I couldn't
         // reduce it enough :(
-        self.template_args().map_or(false, |args| {
-            args.len() > 0
-        }) && match self.declaration().kind() {
+        self.template_args().map_or(false, |args| args.len() > 0) &&
+        match self.declaration().kind() {
             CXCursor_ClassTemplatePartialSpecialization |
             CXCursor_TypeAliasTemplateDecl |
             CXCursor_TemplateTemplateParameter => false,
@@ -847,6 +908,26 @@ impl Type {
     }
 }
 
+/// The `CanonicalTypeDeclaration` type exists as proof-by-construction that its
+/// cursor is the canonical declaration for its type. If you have a
+/// `CanonicalTypeDeclaration` instance, you know for sure that the type and
+/// cursor match up in a canonical declaration relationship, and it simply
+/// cannot be otherwise.
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub struct CanonicalTypeDeclaration(Type, Cursor);
+
+impl CanonicalTypeDeclaration {
+    /// Get the type.
+    pub fn ty(&self) -> &Type {
+        &self.0
+    }
+
+    /// Get the type's canonical declaration cursor.
+    pub fn cursor(&self) -> &Cursor {
+        &self.1
+    }
+}
+
 /// An iterator for a type's template arguments.
 pub struct TypeTemplateArgIterator {
     x: CXType,
@@ -1389,7 +1470,10 @@ pub fn ast_dump(c: &Cursor, depth: isize) -> CXChildVisitResult {
                                  type_to_str(ty.kind())));
         }
         if let Some(ty) = c.ret_type() {
-            print_indent(depth, format!(" {}ret-type = {}", prefix, type_to_str(ty.kind())));
+            print_indent(depth,
+                         format!(" {}ret-type = {}",
+                                 prefix,
+                                 type_to_str(ty.kind())));
         }
 
         if let Some(refd) = c.referenced() {
@@ -1398,7 +1482,9 @@ pub fn ast_dump(c: &Cursor, depth: isize) -> CXChildVisitResult {
                 print_cursor(depth,
                              String::from(prefix) + "referenced.",
                              &refd);
-                print_cursor(depth, String::from(prefix) + "referenced.", &refd);
+                print_cursor(depth,
+                             String::from(prefix) + "referenced.",
+                             &refd);
             }
         }
 
@@ -1408,7 +1494,9 @@ pub fn ast_dump(c: &Cursor, depth: isize) -> CXChildVisitResult {
             print_cursor(depth,
                          String::from(prefix) + "canonical.",
                          &canonical);
-            print_cursor(depth, String::from(prefix) + "canonical.", &canonical);
+            print_cursor(depth,
+                         String::from(prefix) + "canonical.",
+                         &canonical);
         }
 
         if let Some(specialized) = c.specialized() {
@@ -1417,7 +1505,9 @@ pub fn ast_dump(c: &Cursor, depth: isize) -> CXChildVisitResult {
                 print_cursor(depth,
                              String::from(prefix) + "specialized.",
                              &specialized);
-                print_cursor(depth, String::from(prefix) + "specialized.", &specialized);
+                print_cursor(depth,
+                             String::from(prefix) + "specialized.",
+                             &specialized);
             }
         }
     }

src/codegen/helpers.rs

@@ -89,9 +89,7 @@ pub mod ast_ty {
                 let prefix = ctx.rust_ident_raw(prefix);
                 quote_ty!(ctx.ext_cx(), $prefix::$ident)
             }
-            None => {
-                quote_ty!(ctx.ext_cx(), ::std::os::raw::$ident)
-            }
+            None => quote_ty!(ctx.ext_cx(), ::std::os::raw::$ident),
         }
     }
 

src/codegen/mod.rs

@@ -521,7 +521,7 @@ impl CodeGenerator for Type {
             TypeKind::Pointer(..) |
             TypeKind::BlockPointer |
             TypeKind::Reference(..) |
-            TypeKind::TemplateRef(..) |
+            TypeKind::TemplateInstantiation(..) |
             TypeKind::Function(..) |
             TypeKind::ResolvedTypeRef(..) |
             TypeKind::Named => {
@@ -1377,9 +1377,10 @@ impl CodeGenerator for CompInfo {
                 // FIXME when [issue #465](https://github.com/servo/rust-bindgen/issues/465) ready
                 let too_many_base_vtables = self.base_members()
                     .iter()
-                    .filter(|base| ctx.resolve_type(base.ty).has_vtable(ctx))
-                    .count() >
-                                            1;
+                    .filter(|base| {
+                        ctx.resolve_type(base.ty).has_vtable(ctx)
+                    })
+                    .count() > 1;
 
                 let should_skip_field_offset_checks = item.is_opaque(ctx) ||
                                                       too_many_base_vtables;
@@ -2180,7 +2181,7 @@ impl ToRustTy for Type {
                 let path = item.namespace_aware_canonical_path(ctx);
                 aster::AstBuilder::new().ty().path().ids(path).build()
             }
-            TypeKind::TemplateRef(inner, ref template_args) => {
+            TypeKind::TemplateInstantiation(inner, ref template_args) => {
                 // PS: Sorry for the duplication here.
                 let mut inner_ty = inner.to_rust_ty(ctx).unwrap();
 
@@ -2189,7 +2190,7 @@ impl ToRustTy for Type {
                         .map(|arg| arg.to_rust_ty(ctx))
                         .collect::<Vec<_>>();
 
-                    path.segments.last_mut().unwrap().parameters = if
+                    path.segments.last_mut().unwrap().parameters = if 
                         template_args.is_empty() {
                         None
                     } else {
@@ -2509,8 +2510,8 @@ mod utils {
     use super::ItemToRustTy;
     use aster;
     use ir::context::{BindgenContext, ItemId};
-    use ir::item::{Item, ItemCanonicalPath};
     use ir::function::FunctionSig;
+    use ir::item::{Item, ItemCanonicalPath};
     use ir::ty::TypeKind;
     use std::mem;
     use syntax::ast;

src/ir/comp.rs

@@ -5,7 +5,7 @@ use super::context::{BindgenContext, ItemId};
 use super::derive::{CanDeriveCopy, CanDeriveDebug, CanDeriveDefault};
 use super::item::Item;
 use super::layout::Layout;
-use super::ty::Type;
+use super::ty::{TemplateDeclaration, Type};
 use super::type_collector::{ItemSet, TypeCollector};
 use clang;
 use parse::{ClangItemParser, ParseError};
@@ -559,10 +559,8 @@ impl CompInfo {
                 _ => false,
             });
         ci.template_args = match ty.template_args() {
-            // In forward declarations and not specializations,
-            // etc, they are in
-            // the ast, we'll meet them in
-            // CXCursor_TemplateTypeParameter
+            // In forward declarations and not specializations, etc, they are in
+            // the ast, we'll meet them in CXCursor_TemplateTypeParameter
             None => vec![],
             Some(arg_types) => {
                 let num_arg_types = arg_types.len();
@@ -911,6 +909,16 @@ impl CompInfo {
     }
 }
 
+impl TemplateDeclaration for CompInfo {
+    fn template_params(&self, _ctx: &BindgenContext) -> Option<Vec<ItemId>> {
+        if self.template_args.is_empty() {
+            None
+        } else {
+            Some(self.template_args.clone())
+        }
+    }
+}
+
 impl CanDeriveDebug for CompInfo {
     type Extra = Option<Layout>;