pickle.cc revision a3f6a49ab37290eeeb8db0f41ec0f1cb74a68be7 
1// Copyright (c) 2012 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#include "base/pickle.h"
6
7#include <stdlib.h>
8
9#include <algorithm>  // for max()
10
11//------------------------------------------------------------------------------
12
13using base::char16;
14using base::string16;
15
16// static
17const int Pickle::kPayloadUnit = 64;
18
19static const size_t kCapacityReadOnly = static_cast<size_t>(-1);
20
21PickleIterator::PickleIterator(const Pickle& pickle)
22    : read_ptr_(pickle.payload()),
23      read_end_ptr_(pickle.end_of_payload()) {
24}
25
26template <typename Type>
27inline bool PickleIterator::ReadBuiltinType(Type* result) {
28  const char* read_from = GetReadPointerAndAdvance<Type>();
29  if (!read_from)
30    return false;
31  if (sizeof(Type) > sizeof(uint32))
32    memcpy(result, read_from, sizeof(*result));
33  else
34    *result = *reinterpret_cast<const Type*>(read_from);
35  return true;
36}
37
38template<typename Type>
39inline const char* PickleIterator::GetReadPointerAndAdvance() {
40  const char* current_read_ptr = read_ptr_;
41  if (read_ptr_ + sizeof(Type) > read_end_ptr_)
42    return NULL;
43  if (sizeof(Type) < sizeof(uint32))
44    read_ptr_ += AlignInt(sizeof(Type), sizeof(uint32));
45  else
46    read_ptr_ += sizeof(Type);
47  return current_read_ptr;
48}
49
50const char* PickleIterator::GetReadPointerAndAdvance(int num_bytes) {
51  if (num_bytes < 0 || read_end_ptr_ - read_ptr_ < num_bytes)
52    return NULL;
53  const char* current_read_ptr = read_ptr_;
54  read_ptr_ += AlignInt(num_bytes, sizeof(uint32));
55  return current_read_ptr;
56}
57
58inline const char* PickleIterator::GetReadPointerAndAdvance(int num_elements,
59                                                          size_t size_element) {
60  // Check for int32 overflow.
61  int64 num_bytes = static_cast<int64>(num_elements) * size_element;
62  int num_bytes32 = static_cast<int>(num_bytes);
63  if (num_bytes != static_cast<int64>(num_bytes32))
64    return NULL;
65  return GetReadPointerAndAdvance(num_bytes32);
66}
67
68bool PickleIterator::ReadBool(bool* result) {
69  return ReadBuiltinType(result);
70}
71
72bool PickleIterator::ReadInt(int* result) {
73  return ReadBuiltinType(result);
74}
75
76bool PickleIterator::ReadLong(long* result) {
77  return ReadBuiltinType(result);
78}
79
80bool PickleIterator::ReadUInt16(uint16* result) {
81  return ReadBuiltinType(result);
82}
83
84bool PickleIterator::ReadUInt32(uint32* result) {
85  return ReadBuiltinType(result);
86}
87
88bool PickleIterator::ReadInt64(int64* result) {
89  return ReadBuiltinType(result);
90}
91
92bool PickleIterator::ReadUInt64(uint64* result) {
93  return ReadBuiltinType(result);
94}
95
96bool PickleIterator::ReadFloat(float* result) {
97  // crbug.com/315213
98  // The source data may not be properly aligned, and unaligned float reads
99  // cause SIGBUS on some ARM platforms, so force using memcpy to copy the data
100  // into the result.
101  const char* read_from = GetReadPointerAndAdvance<float>();
102  if (!read_from)
103    return false;
104  memcpy(result, read_from, sizeof(*result));
105  return true;
106}
107
108bool PickleIterator::ReadString(std::string* result) {
109  int len;
110  if (!ReadInt(&len))
111    return false;
112  const char* read_from = GetReadPointerAndAdvance(len);
113  if (!read_from)
114    return false;
115
116  result->assign(read_from, len);
117  return true;
118}
119
120bool PickleIterator::ReadWString(std::wstring* result) {
121  int len;
122  if (!ReadInt(&len))
123    return false;
124  const char* read_from = GetReadPointerAndAdvance(len, sizeof(wchar_t));
125  if (!read_from)
126    return false;
127
128  result->assign(reinterpret_cast<const wchar_t*>(read_from), len);
129  return true;
130}
131
132bool PickleIterator::ReadString16(string16* result) {
133  int len;
134  if (!ReadInt(&len))
135    return false;
136  const char* read_from = GetReadPointerAndAdvance(len, sizeof(char16));
137  if (!read_from)
138    return false;
139
140  result->assign(reinterpret_cast<const char16*>(read_from), len);
141  return true;
142}
143
144bool PickleIterator::ReadData(const char** data, int* length) {
145  *length = 0;
146  *data = 0;
147
148  if (!ReadInt(length))
149    return false;
150
151  return ReadBytes(data, *length);
152}
153
154bool PickleIterator::ReadBytes(const char** data, int length) {
155  const char* read_from = GetReadPointerAndAdvance(length);
156  if (!read_from)
157    return false;
158  *data = read_from;
159  return true;
160}
161
162// Payload is uint32 aligned.
163
164Pickle::Pickle()
165    : header_(NULL),
166      header_size_(sizeof(Header)),
167      capacity_after_header_(0),
168      write_offset_(0) {
169  Resize(kPayloadUnit);
170  header_->payload_size = 0;
171}
172
173Pickle::Pickle(int header_size)
174    : header_(NULL),
175      header_size_(AlignInt(header_size, sizeof(uint32))),
176      capacity_after_header_(0),
177      write_offset_(0) {
178  DCHECK_GE(static_cast<size_t>(header_size), sizeof(Header));
179  DCHECK_LE(header_size, kPayloadUnit);
180  Resize(kPayloadUnit);
181  header_->payload_size = 0;
182}
183
184Pickle::Pickle(const char* data, int data_len)
185    : header_(reinterpret_cast<Header*>(const_cast<char*>(data))),
186      header_size_(0),
187      capacity_after_header_(kCapacityReadOnly),
188      write_offset_(0) {
189  if (data_len >= static_cast<int>(sizeof(Header)))
190    header_size_ = data_len - header_->payload_size;
191
192  if (header_size_ > static_cast<unsigned int>(data_len))
193    header_size_ = 0;
194
195  if (header_size_ != AlignInt(header_size_, sizeof(uint32)))
196    header_size_ = 0;
197
198  // If there is anything wrong with the data, we're not going to use it.
199  if (!header_size_)
200    header_ = NULL;
201}
202
203Pickle::Pickle(const Pickle& other)
204    : header_(NULL),
205      header_size_(other.header_size_),
206      capacity_after_header_(0),
207      write_offset_(other.write_offset_) {
208  size_t payload_size = header_size_ + other.header_->payload_size;
209  Resize(payload_size);
210  memcpy(header_, other.header_, payload_size);
211}
212
213Pickle::~Pickle() {
214  if (capacity_after_header_ != kCapacityReadOnly)
215    free(header_);
216}
217
218Pickle& Pickle::operator=(const Pickle& other) {
219  if (this == &other) {
220    NOTREACHED();
221    return *this;
222  }
223  if (capacity_after_header_ == kCapacityReadOnly) {
224    header_ = NULL;
225    capacity_after_header_ = 0;
226  }
227  if (header_size_ != other.header_size_) {
228    free(header_);
229    header_ = NULL;
230    header_size_ = other.header_size_;
231  }
232  Resize(other.header_->payload_size);
233  memcpy(header_, other.header_,
234         other.header_size_ + other.header_->payload_size);
235  write_offset_ = other.write_offset_;
236  return *this;
237}
238
239bool Pickle::WriteString(const std::string& value) {
240  if (!WriteInt(static_cast<int>(value.size())))
241    return false;
242
243  return WriteBytes(value.data(), static_cast<int>(value.size()));
244}
245
246bool Pickle::WriteWString(const std::wstring& value) {
247  if (!WriteInt(static_cast<int>(value.size())))
248    return false;
249
250  return WriteBytes(value.data(),
251                    static_cast<int>(value.size() * sizeof(wchar_t)));
252}
253
254bool Pickle::WriteString16(const string16& value) {
255  if (!WriteInt(static_cast<int>(value.size())))
256    return false;
257
258  return WriteBytes(value.data(),
259                    static_cast<int>(value.size()) * sizeof(char16));
260}
261
262bool Pickle::WriteData(const char* data, int length) {
263  return length >= 0 && WriteInt(length) && WriteBytes(data, length);
264}
265
266bool Pickle::WriteBytes(const void* data, int length) {
267  WriteBytesCommon(data, length);
268  return true;
269}
270
271void Pickle::Reserve(size_t length) {
272  size_t data_len = AlignInt(length, sizeof(uint32));
273  DCHECK_GE(data_len, length);
274#ifdef ARCH_CPU_64_BITS
275  DCHECK_LE(data_len, kuint32max);
276#endif
277  DCHECK_LE(write_offset_, kuint32max - data_len);
278  size_t new_size = write_offset_ + data_len;
279  if (new_size > capacity_after_header_)
280    Resize(capacity_after_header_ * 2 + new_size);
281}
282
283void Pickle::Resize(size_t new_capacity) {
284  new_capacity = AlignInt(new_capacity, kPayloadUnit);
285
286  CHECK_NE(capacity_after_header_, kCapacityReadOnly);
287  void* p = realloc(header_, header_size_ + new_capacity);
288  CHECK(p);
289  header_ = reinterpret_cast<Header*>(p);
290  capacity_after_header_ = new_capacity;
291}
292
293// static
294const char* Pickle::FindNext(size_t header_size,
295                             const char* start,
296                             const char* end) {
297  DCHECK_EQ(header_size, AlignInt(header_size, sizeof(uint32)));
298  DCHECK_LE(header_size, static_cast<size_t>(kPayloadUnit));
299
300  size_t length = static_cast<size_t>(end - start);
301  if (length < sizeof(Header))
302    return NULL;
303
304  const Header* hdr = reinterpret_cast<const Header*>(start);
305  if (length < header_size || length - header_size < hdr->payload_size)
306    return NULL;
307  return start + header_size + hdr->payload_size;
308}
309
310template <size_t length> void Pickle::WriteBytesStatic(const void* data) {
311  WriteBytesCommon(data, length);
312}
313
314template void Pickle::WriteBytesStatic<2>(const void* data);
315template void Pickle::WriteBytesStatic<4>(const void* data);
316template void Pickle::WriteBytesStatic<8>(const void* data);
317
318inline void Pickle::WriteBytesCommon(const void* data, size_t length) {
319  DCHECK_NE(kCapacityReadOnly, capacity_after_header_)
320      << "oops: pickle is readonly";
321  size_t data_len = AlignInt(length, sizeof(uint32));
322  DCHECK_GE(data_len, length);
323#ifdef ARCH_CPU_64_BITS
324  DCHECK_LE(data_len, kuint32max);
325#endif
326  DCHECK_LE(write_offset_, kuint32max - data_len);
327  size_t new_size = write_offset_ + data_len;
328  if (new_size > capacity_after_header_) {
329    Resize(std::max(capacity_after_header_ * 2, new_size));
330  }
331
332  char* write = mutable_payload() + write_offset_;
333  memcpy(write, data, length);
334  memset(write + length, 0, data_len - length);
335  header_->payload_size = static_cast<uint32>(write_offset_ + length);
336  write_offset_ = new_size;
337}
338