Mojo C++ bindings: support Arrays that contain Maps.

mojo/public/cpp/bindings/lib/bindings_internal.h

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef MOJO_PUBLIC_CPP_BINDINGS_LIB_BINDINGS_INTERNAL_H_
 #define MOJO_PUBLIC_CPP_BINDINGS_LIB_BINDINGS_INTERNAL_H_
 
 #include "mojo/public/cpp/bindings/lib/template_util.h"
 #include "mojo/public/cpp/system/core.h"
 
 namespace mojo {
 class String;
+template <typename Key, typename Value> class Map;
 
 namespace internal {
 template <typename T> class Array_Data;
 
 #pragma pack(push, 1)
 
 struct StructHeader {
   uint32_t num_bytes;
   uint32_t num_fields;
 };
@@ skipping 18 matching lines @@
   Array_Data<T>* ptr;
 };
 MOJO_COMPILE_ASSERT(sizeof(ArrayPointer<char>) == 8, bad_sizeof_ArrayPointer);
 
 union StringPointer {
   uint64_t offset;
   Array_Data<char>* ptr;
 };
 MOJO_COMPILE_ASSERT(sizeof(StringPointer) == 8, bad_sizeof_StringPointer);
 
+template <typename Key, typename Value>
+struct MapPointerPair {
+  ArrayPointer<Key> keys;
+  ArrayPointer<Value> values;
+};
+MOJO_COMPILE_ASSERT(sizeof(MapPointerPair<char, char>) == 16,
+                    bad_sizeof_MapPointerPair);
+
 #pragma pack(pop)
 
 template <typename T>
 void ResetIfNonNull(T* ptr) {
   if (ptr)
     *ptr = T();
 }
 
 template <typename T>
 T FetchAndReset(T* ptr) {
   T temp = *ptr;
   *ptr = T();
   return temp;
 }
 
 template <typename H> struct IsHandle {
   enum { value = IsBaseOf<Handle, H>::value };
 };
 
 template <typename T, bool move_only = IsMoveOnlyType<T>::value>
 struct WrapperTraits;
 
 template <typename T> struct WrapperTraits<T, false> {
   typedef T DataType;
 };
 template <typename H> struct WrapperTraits<ScopedHandleBase<H>, true> {
   typedef H DataType;
 };
+template <typename KeyWrapperType, typename ValueWrapperType>
+struct WrapperTraits<Map<KeyWrapperType, ValueWrapperType>, true> {
+  typedef MapPointerPair<
+      typename WrapperTraits<KeyWrapperType>::DataType,
+      typename WrapperTraits<ValueWrapperType>::DataType> DataType;
+};
 template <typename S> struct WrapperTraits<S, true> {
   typedef typename S::Data_* DataType;
 };
 
 }  // namespace internal
 }  // namespace mojo
 
 #endif  // MOJO_PUBLIC_CPP_BINDINGS_LIB_BINDINGS_INTERNAL_H_