1// Copyright (c) 2011 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#include <limits>
11
12//------------------------------------------------------------------------------
13
14// static
15const int Pickle::kPayloadUnit = 64;
16
17// We mark a read only pickle with a special capacity_.
18static const size_t kCapacityReadOnly = std::numeric_limits<size_t>::max();
19
20// Payload is uint32 aligned.
21
22Pickle::Pickle()
23    : header_(NULL),
24      header_size_(sizeof(Header)),
25      capacity_(0),
26      variable_buffer_offset_(0) {
27  Resize(kPayloadUnit);
28  header_->payload_size = 0;
29}
30
31Pickle::Pickle(int header_size)
32    : header_(NULL),
33      header_size_(AlignInt(header_size, sizeof(uint32))),
34      capacity_(0),
35      variable_buffer_offset_(0) {
36  DCHECK_GE(static_cast<size_t>(header_size), sizeof(Header));
37  DCHECK(header_size <= kPayloadUnit);
38  Resize(kPayloadUnit);
39  header_->payload_size = 0;
40}
41
42Pickle::Pickle(const char* data, int data_len)
43    : header_(reinterpret_cast<Header*>(const_cast<char*>(data))),
44      header_size_(0),
45      capacity_(kCapacityReadOnly),
46      variable_buffer_offset_(0) {
47  if (data_len >= static_cast<int>(sizeof(Header)))
48    header_size_ = data_len - header_->payload_size;
49
50  if (header_size_ > static_cast<unsigned int>(data_len))
51    header_size_ = 0;
52
53  if (header_size_ != AlignInt(header_size_, sizeof(uint32)))
54    header_size_ = 0;
55
56  // If there is anything wrong with the data, we're not going to use it.
57  if (!header_size_)
58    header_ = NULL;
59}
60
61Pickle::Pickle(const Pickle& other)
62    : header_(NULL),
63      header_size_(other.header_size_),
64      capacity_(0),
65      variable_buffer_offset_(other.variable_buffer_offset_) {
66  size_t payload_size = header_size_ + other.header_->payload_size;
67  bool resized = Resize(payload_size);
68  CHECK(resized);  // Realloc failed.
69  memcpy(header_, other.header_, payload_size);
70}
71
72Pickle::~Pickle() {
73  if (capacity_ != kCapacityReadOnly)
74    free(header_);
75}
76
77Pickle& Pickle::operator=(const Pickle& other) {
78  if (this == &other) {
79    NOTREACHED();
80    return *this;
81  }
82  if (capacity_ == kCapacityReadOnly) {
83    header_ = NULL;
84    capacity_ = 0;
85  }
86  if (header_size_ != other.header_size_) {
87    free(header_);
88    header_ = NULL;
89    header_size_ = other.header_size_;
90  }
91  bool resized = Resize(other.header_size_ + other.header_->payload_size);
92  CHECK(resized);  // Realloc failed.
93  memcpy(header_, other.header_,
94         other.header_size_ + other.header_->payload_size);
95  variable_buffer_offset_ = other.variable_buffer_offset_;
96  return *this;
97}
98
99bool Pickle::ReadBool(void** iter, bool* result) const {
100  DCHECK(iter);
101
102  int tmp;
103  if (!ReadInt(iter, &tmp))
104    return false;
105  DCHECK(0 == tmp || 1 == tmp);
106  *result = tmp ? true : false;
107  return true;
108}
109
110bool Pickle::ReadInt(void** iter, int* result) const {
111  DCHECK(iter);
112  if (!*iter)
113    *iter = const_cast<char*>(payload());
114
115  if (!IteratorHasRoomFor(*iter, sizeof(*result)))
116    return false;
117
118  // TODO(jar): http://crbug.com/13108 Pickle should be cleaned up, and not
119  // dependent on alignment.
120  // Next line is otherwise the same as: memcpy(result, *iter, sizeof(*result));
121  *result = *reinterpret_cast<int*>(*iter);
122
123  UpdateIter(iter, sizeof(*result));
124  return true;
125}
126
127bool Pickle::ReadLong(void** iter, long* result) const {
128  DCHECK(iter);
129  if (!*iter)
130    *iter = const_cast<char*>(payload());
131
132  if (!IteratorHasRoomFor(*iter, sizeof(*result)))
133    return false;
134
135  // TODO(jar): http://crbug.com/13108 Pickle should be cleaned up, and not
136  // dependent on alignment.
137  memcpy(result, *iter, sizeof(*result));
138
139  UpdateIter(iter, sizeof(*result));
140  return true;
141}
142
143bool Pickle::ReadSize(void** iter, size_t* result) const {
144  DCHECK(iter);
145  if (!*iter)
146    *iter = const_cast<char*>(payload());
147
148  if (!IteratorHasRoomFor(*iter, sizeof(*result)))
149    return false;
150
151  // TODO(jar): http://crbug.com/13108 Pickle should be cleaned up, and not
152  // dependent on alignment.
153  // Next line is otherwise the same as: memcpy(result, *iter, sizeof(*result));
154  *result = *reinterpret_cast<size_t*>(*iter);
155
156  UpdateIter(iter, sizeof(*result));
157  return true;
158}
159
160bool Pickle::ReadUInt16(void** iter, uint16* result) const {
161  DCHECK(iter);
162  if (!*iter)
163    *iter = const_cast<char*>(payload());
164
165  if (!IteratorHasRoomFor(*iter, sizeof(*result)))
166    return false;
167
168  memcpy(result, *iter, sizeof(*result));
169
170  UpdateIter(iter, sizeof(*result));
171  return true;
172}
173
174bool Pickle::ReadUInt32(void** iter, uint32* result) const {
175  DCHECK(iter);
176  if (!*iter)
177    *iter = const_cast<char*>(payload());
178
179  if (!IteratorHasRoomFor(*iter, sizeof(*result)))
180    return false;
181
182  memcpy(result, *iter, sizeof(*result));
183
184  UpdateIter(iter, sizeof(*result));
185  return true;
186}
187
188bool Pickle::ReadInt64(void** iter, int64* result) const {
189  DCHECK(iter);
190  if (!*iter)
191    *iter = const_cast<char*>(payload());
192
193  if (!IteratorHasRoomFor(*iter, sizeof(*result)))
194    return false;
195
196  memcpy(result, *iter, sizeof(*result));
197
198  UpdateIter(iter, sizeof(*result));
199  return true;
200}
201
202bool Pickle::ReadUInt64(void** iter, uint64* result) const {
203  DCHECK(iter);
204  if (!*iter)
205    *iter = const_cast<char*>(payload());
206
207  if (!IteratorHasRoomFor(*iter, sizeof(*result)))
208    return false;
209
210  memcpy(result, *iter, sizeof(*result));
211
212  UpdateIter(iter, sizeof(*result));
213  return true;
214}
215
216bool Pickle::ReadString(void** iter, std::string* result) const {
217  DCHECK(iter);
218
219  int len;
220  if (!ReadLength(iter, &len))
221    return false;
222  if (!IteratorHasRoomFor(*iter, len))
223    return false;
224
225  char* chars = reinterpret_cast<char*>(*iter);
226  result->assign(chars, len);
227
228  UpdateIter(iter, len);
229  return true;
230}
231
232bool Pickle::ReadWString(void** iter, std::wstring* result) const {
233  DCHECK(iter);
234
235  int len;
236  if (!ReadLength(iter, &len))
237    return false;
238  // Avoid integer overflow.
239  if (len > INT_MAX / static_cast<int>(sizeof(wchar_t)))
240    return false;
241  if (!IteratorHasRoomFor(*iter, len * sizeof(wchar_t)))
242    return false;
243
244  wchar_t* chars = reinterpret_cast<wchar_t*>(*iter);
245  result->assign(chars, len);
246
247  UpdateIter(iter, len * sizeof(wchar_t));
248  return true;
249}
250
251bool Pickle::ReadString16(void** iter, string16* result) const {
252  DCHECK(iter);
253
254  int len;
255  if (!ReadLength(iter, &len))
256    return false;
257  if (!IteratorHasRoomFor(*iter, len * sizeof(char16)))
258    return false;
259
260  char16* chars = reinterpret_cast<char16*>(*iter);
261  result->assign(chars, len);
262
263  UpdateIter(iter, len * sizeof(char16));
264  return true;
265}
266
267bool Pickle::ReadData(void** iter, const char** data, int* length) const {
268  DCHECK(iter);
269  DCHECK(data);
270  DCHECK(length);
271  *length = 0;
272  *data = 0;
273
274  if (!ReadLength(iter, length))
275    return false;
276
277  return ReadBytes(iter, data, *length);
278}
279
280bool Pickle::ReadBytes(void** iter, const char** data, int length) const {
281  DCHECK(iter);
282  DCHECK(data);
283  *data = 0;
284  if (!*iter)
285    *iter = const_cast<char*>(payload());
286
287  if (!IteratorHasRoomFor(*iter, length))
288    return false;
289
290  *data = reinterpret_cast<const char*>(*iter);
291
292  UpdateIter(iter, length);
293  return true;
294}
295
296bool Pickle::ReadLength(void** iter, int* result) const {
297  if (!ReadInt(iter, result))
298    return false;
299  return ((*result) >= 0);
300}
301
302bool Pickle::WriteString(const std::string& value) {
303  if (!WriteInt(static_cast<int>(value.size())))
304    return false;
305
306  return WriteBytes(value.data(), static_cast<int>(value.size()));
307}
308
309bool Pickle::WriteWString(const std::wstring& value) {
310  if (!WriteInt(static_cast<int>(value.size())))
311    return false;
312
313  return WriteBytes(value.data(),
314                    static_cast<int>(value.size() * sizeof(wchar_t)));
315}
316
317bool Pickle::WriteString16(const string16& value) {
318  if (!WriteInt(static_cast<int>(value.size())))
319    return false;
320
321  return WriteBytes(value.data(),
322                    static_cast<int>(value.size()) * sizeof(char16));
323}
324
325bool Pickle::WriteData(const char* data, int length) {
326  return length >= 0 && WriteInt(length) && WriteBytes(data, length);
327}
328
329bool Pickle::WriteBytes(const void* data, int data_len) {
330  DCHECK(capacity_ != kCapacityReadOnly) << "oops: pickle is readonly";
331
332  char* dest = BeginWrite(data_len);
333  if (!dest)
334    return false;
335
336  memcpy(dest, data, data_len);
337
338  EndWrite(dest, data_len);
339  return true;
340}
341
342char* Pickle::BeginWriteData(int length) {
343  DCHECK_EQ(variable_buffer_offset_, 0U) <<
344    "There can only be one variable buffer in a Pickle";
345
346  if (length < 0 || !WriteInt(length))
347    return NULL;
348
349  char *data_ptr = BeginWrite(length);
350  if (!data_ptr)
351    return NULL;
352
353  variable_buffer_offset_ =
354      data_ptr - reinterpret_cast<char*>(header_) - sizeof(int);
355
356  // EndWrite doesn't necessarily have to be called after the write operation,
357  // so we call it here to pad out what the caller will eventually write.
358  EndWrite(data_ptr, length);
359  return data_ptr;
360}
361
362void Pickle::TrimWriteData(int new_length) {
363  DCHECK_NE(variable_buffer_offset_, 0U);
364
365  // Fetch the the variable buffer size
366  int* cur_length = reinterpret_cast<int*>(
367      reinterpret_cast<char*>(header_) + variable_buffer_offset_);
368
369  if (new_length < 0 || new_length > *cur_length) {
370    NOTREACHED() << "Invalid length in TrimWriteData.";
371    return;
372  }
373
374  // Update the payload size and variable buffer size
375  header_->payload_size -= (*cur_length - new_length);
376  *cur_length = new_length;
377}
378
379char* Pickle::BeginWrite(size_t length) {
380  // write at a uint32-aligned offset from the beginning of the header
381  size_t offset = AlignInt(header_->payload_size, sizeof(uint32));
382
383  size_t new_size = offset + length;
384  size_t needed_size = header_size_ + new_size;
385  if (needed_size > capacity_ && !Resize(std::max(capacity_ * 2, needed_size)))
386    return NULL;
387
388#ifdef ARCH_CPU_64_BITS
389  DCHECK_LE(length, std::numeric_limits<uint32>::max());
390#endif
391
392  header_->payload_size = static_cast<uint32>(new_size);
393  return payload() + offset;
394}
395
396void Pickle::EndWrite(char* dest, int length) {
397  // Zero-pad to keep tools like purify from complaining about uninitialized
398  // memory.
399  if (length % sizeof(uint32))
400    memset(dest + length, 0, sizeof(uint32) - (length % sizeof(uint32)));
401}
402
403bool Pickle::Resize(size_t new_capacity) {
404  new_capacity = AlignInt(new_capacity, kPayloadUnit);
405
406  CHECK_NE(capacity_, kCapacityReadOnly);
407  void* p = realloc(header_, new_capacity);
408  if (!p)
409    return false;
410
411  header_ = reinterpret_cast<Header*>(p);
412  capacity_ = new_capacity;
413  return true;
414}
415
416// static
417const char* Pickle::FindNext(size_t header_size,
418                             const char* start,
419                             const char* end) {
420  DCHECK(header_size == AlignInt(header_size, sizeof(uint32)));
421  DCHECK(header_size <= static_cast<size_t>(kPayloadUnit));
422
423  if (static_cast<size_t>(end - start) < sizeof(Header))
424    return NULL;
425
426  const Header* hdr = reinterpret_cast<const Header*>(start);
427  const char* payload_base = start + header_size;
428  const char* payload_end = payload_base + hdr->payload_size;
429  if (payload_end < payload_base)
430    return NULL;
431
432  return (payload_end > end) ? NULL : payload_end;
433}
434