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| 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 "webkit/browser/blob/blob_reader.h" |
| 6 |
| 7 #include "net/base/io_buffer.h" |
| 8 #include "net/base/net_errors.h" |
| 9 #include "webkit/browser/blob/local_file_stream_reader.h" |
| 10 #include "webkit/browser/fileapi/file_system_context.h" |
| 11 |
| 12 namespace webkit_blob { |
| 13 |
| 14 namespace { |
| 15 bool IsFileType(BlobData::Item::Type type) { |
| 16 return type == BlobData::Item::TYPE_FILE || |
| 17 type == BlobData::Item::TYPE_FILE_FILESYSTEM; |
| 18 } |
| 19 } // namespace |
| 20 |
| 21 BlobReader::BlobReader( |
| 22 BlobData* blob_data, |
| 23 fileapi::FileSystemContext* file_system_context) |
| 24 : weak_factory_(this), |
| 25 blob_data_(blob_data), |
| 26 file_system_context_(file_system_context), |
| 27 total_size_(0), |
| 28 remaining_bytes_(0), |
| 29 pending_get_file_info_count_(0), |
| 30 current_item_index_(0), |
| 31 current_item_offset_(0), |
| 32 error_(false) { |
| 33 is_counting_size_ = false; |
| 34 has_started_reading_ = false; |
| 35 has_total_size_ = false; |
| 36 initial_offset_ = 0; |
| 37 file_task_runner_ = file_system_context_->default_file_task_runner(); |
| 38 } |
| 39 |
| 40 BlobReader::~BlobReader() { |
| 41 STLDeleteValues(&index_to_reader_); |
| 42 } |
| 43 |
| 44 void BlobReader::SetInitialOffset(int64 offset) { |
| 45 DCHECK(!has_started_reading_); |
| 46 initial_offset_ = offset; |
| 47 } |
| 48 |
| 49 int BlobReader::Read(net::IOBuffer* buf, int buf_len, |
| 50 const net::CompletionCallback& callback) { |
| 51 if (callback.is_null() || !pending_read_callback_.is_null()) |
| 52 return net::ERR_UNEXPECTED; |
| 53 if (error_) |
| 54 return error_; |
| 55 |
| 56 // Keep track of the buffer. |
| 57 DCHECK(!pending_read_buf_.get()); |
| 58 pending_read_buf_ = buf; |
| 59 pending_read_length_ = buf_len; |
| 60 |
| 61 // Before reading, we need to compute the size of blob data elements. |
| 62 if (!has_total_size_) { |
| 63 CountSize(); |
| 64 if (!has_total_size_) { |
| 65 pending_read_callback_ = callback; |
| 66 return net::ERR_IO_PENDING; |
| 67 } |
| 68 } |
| 69 |
| 70 int rv = DoRead(); |
| 71 if (rv == net::ERR_IO_PENDING) |
| 72 pending_read_callback_ = callback; |
| 73 return rv; |
| 74 } |
| 75 |
| 76 int64 BlobReader::GetLength(const net::Int64CompletionCallback& callback) { |
| 77 if (callback.is_null() || pending_size_callback_.is_null()) |
| 78 return net::ERR_UNEXPECTED; |
| 79 if (error_) |
| 80 return error_; |
| 81 if (has_total_size_) |
| 82 return total_size_; |
| 83 |
| 84 CountSize(); |
| 85 if (!has_total_size_) { |
| 86 // We'll complete the callback when we know the total size. |
| 87 pending_size_callback_ = callback; |
| 88 return net::ERR_IO_PENDING; |
| 89 } |
| 90 return total_size_; |
| 91 } |
| 92 |
| 93 void BlobReader::CountSize() { |
| 94 DCHECK(!has_total_size_); |
| 95 if (is_counting_size_) |
| 96 return; |
| 97 pending_get_file_info_count_ = 0; |
| 98 total_size_ = 0; |
| 99 item_length_list_.resize(blob_data_->items().size()); |
| 100 |
| 101 for (size_t i = 0; i < blob_data_->items().size(); ++i) { |
| 102 const BlobData::Item& item = blob_data_->items().at(i); |
| 103 if (IsFileType(item.type())) { |
| 104 ++pending_get_file_info_count_; |
| 105 GetFileStreamReader(i)->GetLength( |
| 106 base::Bind(&BlobReader::DidGetFileItemLength, |
| 107 weak_factory_.GetWeakPtr(), i)); |
| 108 continue; |
| 109 } |
| 110 |
| 111 if (!AddItemLength(i, item.length())) |
| 112 return; |
| 113 } |
| 114 |
| 115 if (pending_get_file_info_count_ == 0) |
| 116 OnSizeCounted(); |
| 117 } |
| 118 |
| 119 bool BlobReader::AddItemLength(size_t index, int64 item_length) { |
| 120 if (item_length > kint64max - total_size_) { |
| 121 OnError(net::ERR_FAILED); |
| 122 return false; |
| 123 } |
| 124 |
| 125 // Cache the size and add it to the total size. |
| 126 DCHECK_LT(index, item_length_list_.size()); |
| 127 item_length_list_[index] = item_length; |
| 128 total_size_ += item_length; |
| 129 return true; |
| 130 } |
| 131 |
| 132 void BlobReader::DidGetFileItemLength(size_t index, int64 result) { |
| 133 // Do nothing if we have already encountered an error. |
| 134 if (error_) |
| 135 return; |
| 136 |
| 137 if (result == net::ERR_UPLOAD_FILE_CHANGED) { |
| 138 OnError(net::ERR_FILE_NOT_FOUND); |
| 139 return; |
| 140 } |
| 141 if (result < 0) { |
| 142 OnError(result); |
| 143 return; |
| 144 } |
| 145 |
| 146 DCHECK_LT(index, blob_data_->items().size()); |
| 147 const BlobData::Item& item = blob_data_->items().at(index); |
| 148 DCHECK(IsFileType(item.type())); |
| 149 |
| 150 uint64 file_length = result; |
| 151 uint64 item_offset = item.offset(); |
| 152 uint64 item_length = item.length(); |
| 153 |
| 154 if (item_offset > file_length) { |
| 155 OnError(net::ERR_FILE_NOT_FOUND); |
| 156 return; |
| 157 } |
| 158 |
| 159 uint64 max_length = file_length - item_offset; |
| 160 |
| 161 // If item length is -1, we need to use the file size being resolved |
| 162 // in the real time. |
| 163 if (item_length == static_cast<uint64>(-1)) { |
| 164 item_length = max_length; |
| 165 } else if (item_length > max_length) { |
| 166 OnError(net::ERR_FILE_NOT_FOUND); |
| 167 return; |
| 168 } |
| 169 |
| 170 if (!AddItemLength(index, item_length)) |
| 171 return; |
| 172 |
| 173 if (--pending_get_file_info_count_ == 0) |
| 174 OnSizeCounted(); |
| 175 } |
| 176 |
| 177 int BlobReader::DoRead() { |
| 178 DCHECK(!error_); |
| 179 DCHECK(pending_read_buf_.get()); |
| 180 |
| 181 if (!has_started_reading_) { |
| 182 has_started_reading_ = true; |
| 183 if (initial_offset_) |
| 184 PerformInitialSeek(); |
| 185 } |
| 186 |
| 187 int desired_read_size = pending_read_length_; |
| 188 |
| 189 if (remaining_bytes_ < desired_read_size) |
| 190 desired_read_size = static_cast<int>(remaining_bytes_); |
| 191 |
| 192 // If we should copy zero bytes because |remaining_bytes_| is zero, short |
| 193 // circuit here. |
| 194 if (!desired_read_size) { |
| 195 pending_read_buf_ = NULL; |
| 196 return 0; |
| 197 } |
| 198 |
| 199 // Keep track of the buffer. |
| 200 DCHECK(!read_buf_.get()); |
| 201 read_buf_ = new net::DrainableIOBuffer(pending_read_buf_, desired_read_size); |
| 202 pending_read_buf_ = NULL; |
| 203 |
| 204 return ReadLoop(); |
| 205 } |
| 206 |
| 207 void BlobReader::PerformInitialSeek() { |
| 208 remaining_bytes_ -= initial_offset_; |
| 209 if (remaining_bytes_ < 0) |
| 210 remaining_bytes_ = 0; |
| 211 |
| 212 int64 offset = initial_offset_; |
| 213 |
| 214 // Private method to skip the initial items when reading from |
| 215 // an offset. |
| 216 for (current_item_index_ = 0; |
| 217 current_item_index_ < blob_data_->items().size() && |
| 218 offset >= item_length_list_[current_item_index_]; |
| 219 ++current_item_index_) { |
| 220 offset -= item_length_list_[current_item_index_]; |
| 221 } |
| 222 |
| 223 // Set the offset that need to jump to for the first item in the range. |
| 224 current_item_offset_ = offset; |
| 225 |
| 226 if (offset == 0) |
| 227 return; |
| 228 |
| 229 // Adjust the offset of the first stream if it is of file type. |
| 230 const BlobData::Item& item = blob_data_->items().at(current_item_index_); |
| 231 if (IsFileType(item.type())) { |
| 232 DeleteCurrentFileReader(); |
| 233 CreateFileStreamReader(current_item_index_, offset); |
| 234 } |
| 235 } |
| 236 |
| 237 |
| 238 int BlobReader::ReadLoop() { |
| 239 // Read until we encounter an error or could not get the data immediately. |
| 240 while (remaining_bytes_ > 0 && read_buf_->BytesRemaining() > 0) { |
| 241 if (!ReadItem()) |
| 242 return error_ ? error_ : net::ERR_IO_PENDING; |
| 243 } |
| 244 return OnReadComplete(); |
| 245 } |
| 246 |
| 247 bool BlobReader::ReadItem() { |
| 248 // Are we done with reading all the blob data? |
| 249 if (remaining_bytes_ == 0) |
| 250 return true; |
| 251 |
| 252 // If we get to the last item but still expect something to read, bail out |
| 253 // since something is wrong. |
| 254 if (current_item_index_ >= blob_data_->items().size()) { |
| 255 OnError(net::ERR_FAILED); |
| 256 return false; |
| 257 } |
| 258 |
| 259 // Compute the bytes to read for current item. |
| 260 int bytes_to_read = ComputeBytesToRead(); |
| 261 |
| 262 // If nothing to read for current item, advance to next item. |
| 263 if (bytes_to_read == 0) { |
| 264 AdvanceItem(); |
| 265 return ReadItem(); |
| 266 } |
| 267 |
| 268 // Do the reading. |
| 269 const BlobData::Item& item = blob_data_->items().at(current_item_index_); |
| 270 if (item.type() == BlobData::Item::TYPE_BYTES) |
| 271 return ReadBytesItem(item, bytes_to_read); |
| 272 if (IsFileType(item.type())) { |
| 273 return ReadFileItem(GetFileStreamReader(current_item_index_), |
| 274 bytes_to_read); |
| 275 } |
| 276 NOTREACHED(); |
| 277 return false; |
| 278 } |
| 279 |
| 280 void BlobReader::AdvanceItem() { |
| 281 // Close the file if the current item is a file. |
| 282 DeleteCurrentFileReader(); |
| 283 |
| 284 // Advance to the next item. |
| 285 current_item_index_++; |
| 286 current_item_offset_ = 0; |
| 287 } |
| 288 |
| 289 void BlobReader::AdvanceBytesRead(int result) { |
| 290 DCHECK_GT(result, 0); |
| 291 |
| 292 // Do we finish reading the current item? |
| 293 current_item_offset_ += result; |
| 294 if (current_item_offset_ == item_length_list_[current_item_index_]) |
| 295 AdvanceItem(); |
| 296 |
| 297 // Subtract the remaining bytes. |
| 298 remaining_bytes_ -= result; |
| 299 DCHECK_GE(remaining_bytes_, 0); |
| 300 |
| 301 // Adjust the read buffer. |
| 302 read_buf_->DidConsume(result); |
| 303 DCHECK_GE(read_buf_->BytesRemaining(), 0); |
| 304 } |
| 305 |
| 306 bool BlobReader::ReadBytesItem(const BlobData::Item& item, |
| 307 int bytes_to_read) { |
| 308 DCHECK_GE(read_buf_->BytesRemaining(), bytes_to_read); |
| 309 |
| 310 memcpy(read_buf_->data(), |
| 311 item.bytes() + item.offset() + current_item_offset_, |
| 312 bytes_to_read); |
| 313 |
| 314 AdvanceBytesRead(bytes_to_read); |
| 315 return true; |
| 316 } |
| 317 |
| 318 bool BlobReader::ReadFileItem(FileStreamReader* reader, int bytes_to_read) { |
| 319 DCHECK_GE(read_buf_->BytesRemaining(), bytes_to_read); |
| 320 DCHECK_GT(bytes_to_read, 0); |
| 321 DCHECK(reader); |
| 322 const int result = reader->Read( |
| 323 read_buf_.get(), |
| 324 bytes_to_read, |
| 325 base::Bind(&BlobReader::DidReadFile, base::Unretained(this))); |
| 326 if (result >= 0) { |
| 327 DidReadFile(result); |
| 328 return true; |
| 329 } |
| 330 if (result == net::ERR_IO_PENDING) |
| 331 return false; |
| 332 OnError(result); |
| 333 return false; |
| 334 } |
| 335 |
| 336 void BlobReader::DidReadFile(int result) { |
| 337 if (result <= 0) { |
| 338 OnError(net::ERR_FAILED); |
| 339 return; |
| 340 } |
| 341 |
| 342 AdvanceBytesRead(result); |
| 343 |
| 344 // If the read buffer is completely filled, we're done. |
| 345 if (!read_buf_->BytesRemaining()) { |
| 346 OnReadComplete(); |
| 347 return; |
| 348 } |
| 349 |
| 350 // Otherwise, continue the reading. |
| 351 ReadLoop(); |
| 352 } |
| 353 |
| 354 int BlobReader::ComputeBytesToRead() const { |
| 355 int64 current_item_length = item_length_list_[current_item_index_]; |
| 356 int64 item_remaining = current_item_length - current_item_offset_; |
| 357 int64 buf_remaining = read_buf_->BytesRemaining(); |
| 358 int64 max_remaining = std::numeric_limits<int>::max(); |
| 359 int64 min = std::min(std::min(std::min(item_remaining, |
| 360 buf_remaining), |
| 361 remaining_bytes_), |
| 362 max_remaining); |
| 363 return static_cast<int>(min); |
| 364 } |
| 365 |
| 366 void BlobReader::OnSizeCounted() { |
| 367 DCHECK(!error_); |
| 368 has_total_size_ = true; |
| 369 remaining_bytes_ = total_size_; |
| 370 if (!pending_read_callback_.is_null()) { |
| 371 DoRead(); |
| 372 } |
| 373 if (!pending_size_callback_.is_null()) { |
| 374 net::Int64CompletionCallback callback = pending_size_callback_; |
| 375 pending_size_callback_.Reset(); |
| 376 callback.Run(total_size_); |
| 377 } |
| 378 } |
| 379 |
| 380 int BlobReader::OnReadComplete() { |
| 381 int bytes_read = read_buf_->BytesConsumed(); |
| 382 read_buf_ = NULL; |
| 383 if (!pending_read_callback_.is_null()) { |
| 384 net::CompletionCallback callback = pending_read_callback_; |
| 385 pending_read_callback_.Reset(); |
| 386 callback.Run(bytes_read); |
| 387 } |
| 388 return bytes_read; |
| 389 } |
| 390 |
| 391 void BlobReader::OnError(int error_code) { |
| 392 DCHECK(error_code); |
| 393 if (error_) |
| 394 return; |
| 395 error_ = error_code; |
| 396 if (!pending_read_callback_.is_null()) { |
| 397 pending_read_callback_.Run(error_code); |
| 398 pending_read_callback_.Reset(); |
| 399 } else if (!pending_size_callback_.is_null()) { |
| 400 pending_size_callback_.Run(error_code); |
| 401 pending_size_callback_.Reset(); |
| 402 } |
| 403 } |
| 404 |
| 405 FileStreamReader* BlobReader::GetFileStreamReader(size_t index) { |
| 406 DCHECK_LT(index, blob_data_->items().size()); |
| 407 const BlobData::Item& item = blob_data_->items().at(index); |
| 408 if (!IsFileType(item.type())) |
| 409 return NULL; |
| 410 if (index_to_reader_.find(index) == index_to_reader_.end()) |
| 411 CreateFileStreamReader(index, 0); |
| 412 DCHECK(index_to_reader_[index]); |
| 413 return index_to_reader_[index]; |
| 414 } |
| 415 |
| 416 void BlobReader::CreateFileStreamReader(size_t index, |
| 417 int64 additional_offset) { |
| 418 DCHECK_LT(index, blob_data_->items().size()); |
| 419 const BlobData::Item& item = blob_data_->items().at(index); |
| 420 DCHECK(IsFileType(item.type())); |
| 421 DCHECK_EQ(0U, index_to_reader_.count(index)); |
| 422 |
| 423 FileStreamReader* reader = NULL; |
| 424 switch (item.type()) { |
| 425 case BlobData::Item::TYPE_FILE: |
| 426 reader = new LocalFileStreamReader(file_task_runner_.get(), |
| 427 item.path(), |
| 428 item.offset() + additional_offset, |
| 429 item.expected_modification_time()); |
| 430 break; |
| 431 case BlobData::Item::TYPE_FILE_FILESYSTEM: |
| 432 reader = file_system_context_->CreateFileStreamReader( |
| 433 fileapi::FileSystemURL(file_system_context_->CrackURL(item.url())), |
| 434 item.offset() + additional_offset, |
| 435 item.expected_modification_time()).release(); |
| 436 break; |
| 437 default: |
| 438 NOTREACHED(); |
| 439 } |
| 440 DCHECK(reader); |
| 441 index_to_reader_[index] = reader; |
| 442 } |
| 443 |
| 444 void BlobReader::DeleteCurrentFileReader() { |
| 445 IndexToReaderMap::iterator found = index_to_reader_.find(current_item_index_); |
| 446 if (found != index_to_reader_.end() && found->second) { |
| 447 delete found->second; |
| 448 index_to_reader_.erase(found); |
| 449 } |
| 450 } |
| 451 |
| 452 } // namespace webkit_blob |
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