C++ bindings

mojo/public/bindings/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_BINDINGS_BINDINGS_INTERNAL_H_
+#define MOJO_PUBLIC_BINDINGS_BINDINGS_INTERNAL_H_
+
+#include <string.h>
+
+#include <vector>
+
+#include "mojo/public/bindings/bindings.h"
+
+namespace mojo {
+namespace internal {
+
+inline void EncodePointer(void* address, uint64_t* offset) {
+  if (!address) {
+    *offset = 0;
+    return;
+  }
+  uint8_t* p_obj = reinterpret_cast<uint8_t*>(address);
+  uint8_t* p_slot = reinterpret_cast<uint8_t*>(offset);
+  assert(p_obj > p_slot);
+  *offset = p_obj - p_slot;
+}
+
+template <typename T>
+inline void DecodePointer(uint64_t* offset, T** ptr) {
+  if (!*offset) {
+    *ptr = NULL;
+    return;
+  }
+  uint8_t* p_slot = reinterpret_cast<uint8_t*>(offset);
+  *ptr = reinterpret_cast<T*>(p_slot + *offset);
+}
+
+template <typename T>
+inline T* Clone(const T* obj, MessageBuffer* buf) {
+  return Traits<T>::Clone(obj, buf);
+}
+
+template <typename T>
+inline void EncodePointersAndHandles(T* obj,
+                                     std::vector<Handle>* handles) {
+  Traits<T>::EncodePointersAndHandles(obj, handles);
+}
+
+template <typename T>
+inline bool DecodePointersAndHandles(T* obj, const Message& message) {
+  return Traits<T>::DecodePointersAndHandles(obj, message);
+}
+
+template <typename T>
+inline void Encode(T* obj, std::vector<Handle>* handles) {
+  if (obj->ptr)
+    EncodePointersAndHandles(obj->ptr, handles);
+  EncodePointer(obj->ptr, &obj->offset);
+}
+
+template <typename T>
+inline bool Decode(T* obj, const Message& message) {
+  DecodePointer(&obj->offset, &obj->ptr);
+  if (obj->ptr) {
+    if (!DecodePointersAndHandles(obj->ptr, message))
+      return false;
+  }
+  // TODO: Validate!
+  return true;
+}
+
+template <typename T>
+struct ArrayHelper {
+  typedef T ElementType;
+
+  static void CloneElements(MessageBuffer* buf,
+                            ArrayHeader* header,
+                            ElementType* elements) {
+  }
+
+  static void EncodePointersAndHandles(ArrayHeader* header,
+                                       ElementType* elements,
+                                       std::vector<Handle>* handles) {
+  }
+  static bool DecodePointersAndHandles(ArrayHeader* header,
+                                       ElementType* elements,
+                                       const Message& message) {
+    return true;
+  }
+};
+
+template <typename P>
+struct ArrayHelper<P*> {
+  typedef StructPointer<P> ElementType;
+
+  static void CloneElements(MessageBuffer* buf,
+                            ArrayHeader* header,
+                            ElementType* elements) {
+    for (uint32_t i = 0; i < header->num_elements; ++i) {
+      if (elements[i].ptr)
+        elements[i].ptr = Clone(elements[i].ptr, buf);
+    }
+  }
+
+  static void EncodePointersAndHandles(ArrayHeader* header,
+                                       ElementType* elements,
+                                       std::vector<Handle>* handles) {
+    for (uint32_t i = 0; i < header->num_elements; ++i)
+      Encode(&elements[i], handles);
+  }
+  static bool DecodePointersAndHandles(ArrayHeader* header,
+                                       ElementType* elements,
+                                       const Message& message) {
+    for (uint32_t i = 0; i < header->num_elements; ++i) {
+      if (!Decode(&elements[i], message))
+        return false;
+    }
+    return true;
+  }
+};
+
+template <typename T>
+class Traits<Array<T> > {
+ public:
+  static Array<T>* Clone(const Array<T>* array, MessageBuffer* buf) {
+    Array<T>* clone = buf->AllocArray<T>(array->header_.num_elements);
+    memcpy(clone, array, array->header_.num_bytes);
+
+    ArrayHelper<T>::CloneElements(buf, &clone->header_, clone->elements_);
+    return clone;
+  }
+
+  static void EncodePointersAndHandles(Array<T>* array,
+                                       std::vector<Handle>* handles) {
+    ArrayHelper<T>::EncodePointersAndHandles(&array->header_, array->elements_,
+                                             handles);
+  }
+
+  static bool DecodePointersAndHandles(Array<T>* array,
+                                       const Message& message) {
+    return ArrayHelper<T>::DecodePointersAndHandles(&array->header_,
+                                                    array->elements_,
+                                                    message);
+  }
+};
+
+}  // namespace internal
+}  // namespace mojo
+
+#endif  // MOJO_PUBLIC_BINDINGS_BINDINGS_INTERNAL_H_