base/pickle.cc

   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
  15 const int Pickle::kPayloadUnit = 64;
  16
  17 // We mark a read only pickle with a special capacity_.
  18 static const size_t kCapacityReadOnly = std::numeric_limits<size_t>::max();
  19
  20 // Payload is uint32 aligned.
  21
  22 Pickle::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
  31 Pickle::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_LE(header_size, kPayloadUnit);
  38   Resize(kPayloadUnit);
  39   header_->payload_size = 0;
  40 }
  41
  42 Pickle::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
  61 Pickle::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
  72 Pickle::~Pickle() {
  73   if (capacity_ != kCapacityReadOnly)
  74     free(header_);
  75 }
  76
  77 Pickle& 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
  99 bool 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
 110 bool 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
 127 bool 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
 143 bool 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
 160 bool 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
 174 bool 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
 188 bool 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
 202 bool 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
 216 bool 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
 232 bool 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
 251 bool 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
 267 bool 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
 280 bool 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
 296 bool Pickle::ReadLength(void** iter, int* result) const {
 297   if (!ReadInt(iter, result))
 298     return false;
 299   return ((*result) >= 0);
 300 }
 301
 302 bool 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
 309 bool 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
 317 bool 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
 325 bool Pickle::WriteData(const char* data, int length) {
 326   return length >= 0 && WriteInt(length) && WriteBytes(data, length);
 327 }
 328
 329 bool Pickle::WriteBytes(const void* data, int data_len) {
 330   DCHECK_NE(kCapacityReadOnly, capacity_) << "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
 342 char* 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
 362 void 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
 379 char* 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
 396 void 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
 403 bool 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
 417 const char* Pickle::FindNext(size_t header_size,
 418                              const char* start,
 419                              const char* end) {
 420   DCHECK_EQ(header_size, AlignInt(header_size, sizeof(uint32)));
 421   DCHECK_LE(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 }