bindings_serialization.h revision 010d83a9304c5a91596085d917d248abff47903a 
1// Copyright 2013 The Chromium Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5#ifndef MOJO_PUBLIC_CPP_BINDINGS_LIB_BINDINGS_SERIALIZATION_H_
6#define MOJO_PUBLIC_CPP_BINDINGS_LIB_BINDINGS_SERIALIZATION_H_
7
8#include <vector>
9
10#include "mojo/public/cpp/bindings/buffer.h"
11#include "mojo/public/cpp/bindings/message.h"
12
13namespace mojo {
14namespace internal {
15
16size_t Align(size_t size);
17char* AlignPointer(char* ptr);
18
19// Pointers are encoded as relative offsets. The offsets are relative to the
20// address of where the offset value is stored, such that the pointer may be
21// recovered with the expression:
22//
23//   ptr = reinterpret_cast<char*>(offset) + *offset
24//
25// A null pointer is encoded as an offset value of 0.
26//
27void EncodePointer(const void* ptr, uint64_t* offset);
28const void* DecodePointerRaw(const uint64_t* offset);
29
30template <typename T>
31inline void DecodePointer(const uint64_t* offset, T** ptr) {
32  *ptr = reinterpret_cast<T*>(const_cast<void*>(DecodePointerRaw(offset)));
33}
34
35// Check that the given pointer references memory contained within the message.
36bool ValidatePointer(const void* ptr, const Message& message);
37
38// Handles are encoded as indices into a vector of handles. These functions
39// manipulate the value of |handle|, mapping it to and from an index.
40void EncodeHandle(Handle* handle, std::vector<Handle>* handles);
41bool DecodeHandle(Handle* handle, std::vector<Handle>* handles);
42
43// The following 2 functions are used to encode/decode all objects (structs and
44// arrays) in a consistent manner.
45
46template <typename T>
47inline void Encode(T* obj, std::vector<Handle>* handles) {
48  if (obj->ptr)
49    obj->ptr->EncodePointersAndHandles(handles);
50  EncodePointer(obj->ptr, &obj->offset);
51}
52
53template <typename T>
54inline bool Decode(T* obj, Message* message) {
55  DecodePointer(&obj->offset, &obj->ptr);
56  if (obj->ptr) {
57    if (!ValidatePointer(obj->ptr, *message))
58      return false;
59    if (!obj->ptr->DecodePointersAndHandles(message))
60      return false;
61  }
62  return true;
63}
64
65}  // namespace internal
66}  // namespace mojo
67
68#endif  // MOJO_PUBLIC_CPP_BINDINGS_LIB_BINDINGS_SERIALIZATION_H_
69