base/pickle.cc

   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
  13 using base::char16;
  14 using base::string16;
  15
  16 // static
  17 const int Pickle::kPayloadUnit = 64;
  18
  19 static const size_t kCapacityReadOnly = static_cast<size_t>(-1);
  20
  21 PickleIterator::PickleIterator(const Pickle& pickle)
  22     : payload_(pickle.payload()),
  23       read_index_(0),
  24       end_index_(pickle.payload_size()) {
  25 }
  26
  27 template <typename Type>
  28 inline bool PickleIterator::ReadBuiltinType(Type* result) {
  29   const char* read_from = GetReadPointerAndAdvance<Type>();
  30   if (!read_from)
  31     return false;
  32   if (sizeof(Type) > sizeof(uint32))
  33     memcpy(result, read_from, sizeof(*result));
  34   else
  35     *result = *reinterpret_cast<const Type*>(read_from);
  36   return true;
  37 }
  38
  39 inline void PickleIterator::Advance(size_t size) {
  40   size_t aligned_size = AlignInt(size, sizeof(uint32_t));
  41   if (end_index_ - read_index_ < aligned_size) {
  42     read_index_ = end_index_;
  43   } else {
  44     read_index_ += aligned_size;
  45   }
  46 }
  47
  48 template<typename Type>
  49 inline const char* PickleIterator::GetReadPointerAndAdvance() {
  50   if (sizeof(Type) > end_index_ - read_index_) {
  51     read_index_ = end_index_;
  52     return NULL;
  53   }
  54   const char* current_read_ptr = payload_ + read_index_;
  55   Advance(sizeof(Type));
  56   return current_read_ptr;
  57 }
  58
  59 const char* PickleIterator::GetReadPointerAndAdvance(int num_bytes) {
  60   if (num_bytes < 0 ||
  61       end_index_ - read_index_ < static_cast<size_t>(num_bytes)) {
  62     read_index_ = end_index_;
  63     return NULL;
  64   }
  65   const char* current_read_ptr = payload_ + read_index_;
  66   Advance(num_bytes);
  67   return current_read_ptr;
  68 }
  69
  70 inline const char* PickleIterator::GetReadPointerAndAdvance(
  71     int num_elements,
  72     size_t size_element) {
  73   // Check for int32 overflow.
  74   int64 num_bytes = static_cast<int64>(num_elements) * size_element;
  75   int num_bytes32 = static_cast<int>(num_bytes);
  76   if (num_bytes != static_cast<int64>(num_bytes32))
  77     return NULL;
  78   return GetReadPointerAndAdvance(num_bytes32);
  79 }
  80
  81 bool PickleIterator::ReadBool(bool* result) {
  82   return ReadBuiltinType(result);
  83 }
  84
  85 bool PickleIterator::ReadInt(int* result) {
  86   return ReadBuiltinType(result);
  87 }
  88
  89 bool PickleIterator::ReadLong(long* result) {
  90   return ReadBuiltinType(result);
  91 }
  92
  93 bool PickleIterator::ReadUInt16(uint16* result) {
  94   return ReadBuiltinType(result);
  95 }
  96
  97 bool PickleIterator::ReadUInt32(uint32* result) {
  98   return ReadBuiltinType(result);
  99 }
 100
 101 bool PickleIterator::ReadInt64(int64* result) {
 102   return ReadBuiltinType(result);
 103 }
 104
 105 bool PickleIterator::ReadUInt64(uint64* result) {
 106   return ReadBuiltinType(result);
 107 }
 108
 109 bool PickleIterator::ReadFloat(float* result) {
 110   // crbug.com/315213
 111   // The source data may not be properly aligned, and unaligned float reads
 112   // cause SIGBUS on some ARM platforms, so force using memcpy to copy the data
 113   // into the result.
 114   const char* read_from = GetReadPointerAndAdvance<float>();
 115   if (!read_from)
 116     return false;
 117   memcpy(result, read_from, sizeof(*result));
 118   return true;
 119 }
 120
 121 bool PickleIterator::ReadDouble(double* result) {
 122   // crbug.com/315213
 123   // The source data may not be properly aligned, and unaligned double reads
 124   // cause SIGBUS on some ARM platforms, so force using memcpy to copy the data
 125   // into the result.
 126   const char* read_from = GetReadPointerAndAdvance<double>();
 127   if (!read_from)
 128     return false;
 129   memcpy(result, read_from, sizeof(*result));
 130   return true;
 131 }
 132
 133 bool PickleIterator::ReadString(std::string* result) {
 134   int len;
 135   if (!ReadInt(&len))
 136     return false;
 137   const char* read_from = GetReadPointerAndAdvance(len);
 138   if (!read_from)
 139     return false;
 140
 141   result->assign(read_from, len);
 142   return true;
 143 }
 144
 145 bool PickleIterator::ReadWString(std::wstring* result) {
 146   int len;
 147   if (!ReadInt(&len))
 148     return false;
 149   const char* read_from = GetReadPointerAndAdvance(len, sizeof(wchar_t));
 150   if (!read_from)
 151     return false;
 152
 153   result->assign(reinterpret_cast<const wchar_t*>(read_from), len);
 154   return true;
 155 }
 156
 157 bool PickleIterator::ReadString16(string16* result) {
 158   int len;
 159   if (!ReadInt(&len))
 160     return false;
 161   const char* read_from = GetReadPointerAndAdvance(len, sizeof(char16));
 162   if (!read_from)
 163     return false;
 164
 165   result->assign(reinterpret_cast<const char16*>(read_from), len);
 166   return true;
 167 }
 168
 169 bool PickleIterator::ReadData(const char** data, int* length) {
 170   *length = 0;
 171   *data = 0;
 172
 173   if (!ReadInt(length))
 174     return false;
 175
 176   return ReadBytes(data, *length);
 177 }
 178
 179 bool PickleIterator::ReadBytes(const char** data, int length) {
 180   const char* read_from = GetReadPointerAndAdvance(length);
 181   if (!read_from)
 182     return false;
 183   *data = read_from;
 184   return true;
 185 }
 186
 187 // Payload is uint32 aligned.
 188
 189 Pickle::Pickle()
 190     : header_(NULL),
 191       header_size_(sizeof(Header)),
 192       capacity_after_header_(0),
 193       write_offset_(0) {
 194   Resize(kPayloadUnit);
 195   header_->payload_size = 0;
 196 }
 197
 198 Pickle::Pickle(int header_size)
 199     : header_(NULL),
 200       header_size_(AlignInt(header_size, sizeof(uint32))),
 201       capacity_after_header_(0),
 202       write_offset_(0) {
 203   DCHECK_GE(static_cast<size_t>(header_size), sizeof(Header));
 204   DCHECK_LE(header_size, kPayloadUnit);
 205   Resize(kPayloadUnit);
 206   header_->payload_size = 0;
 207 }
 208
 209 Pickle::Pickle(const char* data, int data_len)
 210     : header_(reinterpret_cast<Header*>(const_cast<char*>(data))),
 211       header_size_(0),
 212       capacity_after_header_(kCapacityReadOnly),
 213       write_offset_(0) {
 214   if (data_len >= static_cast<int>(sizeof(Header)))
 215     header_size_ = data_len - header_->payload_size;
 216
 217   if (header_size_ > static_cast<unsigned int>(data_len))
 218     header_size_ = 0;
 219
 220   if (header_size_ != AlignInt(header_size_, sizeof(uint32)))
 221     header_size_ = 0;
 222
 223   // If there is anything wrong with the data, we're not going to use it.
 224   if (!header_size_)
 225     header_ = NULL;
 226 }
 227
 228 Pickle::Pickle(const Pickle& other)
 229     : header_(NULL),
 230       header_size_(other.header_size_),
 231       capacity_after_header_(0),
 232       write_offset_(other.write_offset_) {
 233   size_t payload_size = header_size_ + other.header_->payload_size;
 234   Resize(payload_size);
 235   memcpy(header_, other.header_, payload_size);
 236 }
 237
 238 Pickle::~Pickle() {
 239   if (capacity_after_header_ != kCapacityReadOnly)
 240     free(header_);
 241 }
 242
 243 Pickle& Pickle::operator=(const Pickle& other) {
 244   if (this == &other) {
 245     NOTREACHED();
 246     return *this;
 247   }
 248   if (capacity_after_header_ == kCapacityReadOnly) {
 249     header_ = NULL;
 250     capacity_after_header_ = 0;
 251   }
 252   if (header_size_ != other.header_size_) {
 253     free(header_);
 254     header_ = NULL;
 255     header_size_ = other.header_size_;
 256   }
 257   Resize(other.header_->payload_size);
 258   memcpy(header_, other.header_,
 259          other.header_size_ + other.header_->payload_size);
 260   write_offset_ = other.write_offset_;
 261   return *this;
 262 }
 263
 264 bool Pickle::WriteString(const std::string& value) {
 265   if (!WriteInt(static_cast<int>(value.size())))
 266     return false;
 267
 268   return WriteBytes(value.data(), static_cast<int>(value.size()));
 269 }
 270
 271 bool Pickle::WriteWString(const std::wstring& value) {
 272   if (!WriteInt(static_cast<int>(value.size())))
 273     return false;
 274
 275   return WriteBytes(value.data(),
 276                     static_cast<int>(value.size() * sizeof(wchar_t)));
 277 }
 278
 279 bool Pickle::WriteString16(const string16& value) {
 280   if (!WriteInt(static_cast<int>(value.size())))
 281     return false;
 282
 283   return WriteBytes(value.data(),
 284                     static_cast<int>(value.size()) * sizeof(char16));
 285 }
 286
 287 bool Pickle::WriteData(const char* data, int length) {
 288   return length >= 0 && WriteInt(length) && WriteBytes(data, length);
 289 }
 290
 291 bool Pickle::WriteBytes(const void* data, int length) {
 292   WriteBytesCommon(data, length);
 293   return true;
 294 }
 295
 296 void Pickle::Reserve(size_t length) {
 297   size_t data_len = AlignInt(length, sizeof(uint32));
 298   DCHECK_GE(data_len, length);
 299 #ifdef ARCH_CPU_64_BITS
 300   DCHECK_LE(data_len, kuint32max);
 301 #endif
 302   DCHECK_LE(write_offset_, kuint32max - data_len);
 303   size_t new_size = write_offset_ + data_len;
 304   if (new_size > capacity_after_header_)
 305     Resize(capacity_after_header_ * 2 + new_size);
 306 }
 307
 308 void Pickle::Resize(size_t new_capacity) {
 309   new_capacity = AlignInt(new_capacity, kPayloadUnit);
 310
 311   CHECK_NE(capacity_after_header_, kCapacityReadOnly);
 312   void* p = realloc(header_, header_size_ + new_capacity);
 313   CHECK(p);
 314   header_ = reinterpret_cast<Header*>(p);
 315   capacity_after_header_ = new_capacity;
 316 }
 317
 318 // static
 319 const char* Pickle::FindNext(size_t header_size,
 320                              const char* start,
 321                              const char* end) {
 322   DCHECK_EQ(header_size, AlignInt(header_size, sizeof(uint32)));
 323   DCHECK_LE(header_size, static_cast<size_t>(kPayloadUnit));
 324
 325   size_t length = static_cast<size_t>(end - start);
 326   if (length < sizeof(Header))
 327     return NULL;
 328
 329   const Header* hdr = reinterpret_cast<const Header*>(start);
 330   if (length < header_size || length - header_size < hdr->payload_size)
 331     return NULL;
 332   return start + header_size + hdr->payload_size;
 333 }
 334
 335 template <size_t length> void Pickle::WriteBytesStatic(const void* data) {
 336   WriteBytesCommon(data, length);
 337 }
 338
 339 template void Pickle::WriteBytesStatic<2>(const void* data);
 340 template void Pickle::WriteBytesStatic<4>(const void* data);
 341 template void Pickle::WriteBytesStatic<8>(const void* data);
 342
 343 inline void Pickle::WriteBytesCommon(const void* data, size_t length) {
 344   DCHECK_NE(kCapacityReadOnly, capacity_after_header_)
 345       << "oops: pickle is readonly";
 346   size_t data_len = AlignInt(length, sizeof(uint32));
 347   DCHECK_GE(data_len, length);
 348 #ifdef ARCH_CPU_64_BITS
 349   DCHECK_LE(data_len, kuint32max);
 350 #endif
 351   DCHECK_LE(write_offset_, kuint32max - data_len);
 352   size_t new_size = write_offset_ + data_len;
 353   if (new_size > capacity_after_header_) {
 354     Resize(std::max(capacity_after_header_ * 2, new_size));
 355   }
 356
 357   char* write = mutable_payload() + write_offset_;
 358   memcpy(write, data, length);
 359   memset(write + length, 0, data_len - length);
 360   header_->payload_size = static_cast<uint32>(new_size);
 361   write_offset_ = new_size;
 362 }