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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 "net/disk_cache/blockfile/sparse_control.h" | |
6 | |
7 #include "base/bind.h" | |
8 #include "base/format_macros.h" | |
9 #include "base/logging.h" | |
10 #include "base/message_loop/message_loop.h" | |
11 #include "base/strings/string_util.h" | |
12 #include "base/strings/stringprintf.h" | |
13 #include "base/time/time.h" | |
14 #include "net/base/io_buffer.h" | |
15 #include "net/base/net_errors.h" | |
16 #include "net/disk_cache/blockfile/backend_impl.h" | |
17 #include "net/disk_cache/blockfile/entry_impl.h" | |
18 #include "net/disk_cache/blockfile/file.h" | |
19 #include "net/disk_cache/net_log_parameters.h" | |
20 | |
21 using base::Time; | |
22 | |
23 namespace { | |
24 | |
25 // Stream of the sparse data index. | |
26 const int kSparseIndex = 2; | |
27 | |
28 // Stream of the sparse data. | |
29 const int kSparseData = 1; | |
30 | |
31 // We can have up to 64k children. | |
32 const int kMaxMapSize = 8 * 1024; | |
33 | |
34 // The maximum number of bytes that a child can store. | |
35 const int kMaxEntrySize = 0x100000; | |
36 | |
37 // The size of each data block (tracked by the child allocation bitmap). | |
38 const int kBlockSize = 1024; | |
39 | |
40 // Returns the name of a child entry given the base_name and signature of the | |
41 // parent and the child_id. | |
42 // If the entry is called entry_name, child entries will be named something | |
43 // like Range_entry_name:XXX:YYY where XXX is the entry signature and YYY is the | |
44 // number of the particular child. | |
45 std::string GenerateChildName(const std::string& base_name, int64 signature, | |
46 int64 child_id) { | |
47 return base::StringPrintf("Range_%s:%" PRIx64 ":%" PRIx64, base_name.c_str(), | |
48 signature, child_id); | |
49 } | |
50 | |
51 // This class deletes the children of a sparse entry. | |
52 class ChildrenDeleter | |
53 : public base::RefCounted<ChildrenDeleter>, | |
54 public disk_cache::FileIOCallback { | |
55 public: | |
56 ChildrenDeleter(disk_cache::BackendImpl* backend, const std::string& name) | |
57 : backend_(backend->GetWeakPtr()), name_(name), signature_(0) {} | |
58 | |
59 virtual void OnFileIOComplete(int bytes_copied) override; | |
60 | |
61 // Two ways of deleting the children: if we have the children map, use Start() | |
62 // directly, otherwise pass the data address to ReadData(). | |
63 void Start(char* buffer, int len); | |
64 void ReadData(disk_cache::Addr address, int len); | |
65 | |
66 private: | |
67 friend class base::RefCounted<ChildrenDeleter>; | |
68 virtual ~ChildrenDeleter() {} | |
69 | |
70 void DeleteChildren(); | |
71 | |
72 base::WeakPtr<disk_cache::BackendImpl> backend_; | |
73 std::string name_; | |
74 disk_cache::Bitmap children_map_; | |
75 int64 signature_; | |
76 scoped_ptr<char[]> buffer_; | |
77 DISALLOW_COPY_AND_ASSIGN(ChildrenDeleter); | |
78 }; | |
79 | |
80 // This is the callback of the file operation. | |
81 void ChildrenDeleter::OnFileIOComplete(int bytes_copied) { | |
82 char* buffer = buffer_.release(); | |
83 Start(buffer, bytes_copied); | |
84 } | |
85 | |
86 void ChildrenDeleter::Start(char* buffer, int len) { | |
87 buffer_.reset(buffer); | |
88 if (len < static_cast<int>(sizeof(disk_cache::SparseData))) | |
89 return Release(); | |
90 | |
91 // Just copy the information from |buffer|, delete |buffer| and start deleting | |
92 // the child entries. | |
93 disk_cache::SparseData* data = | |
94 reinterpret_cast<disk_cache::SparseData*>(buffer); | |
95 signature_ = data->header.signature; | |
96 | |
97 int num_bits = (len - sizeof(disk_cache::SparseHeader)) * 8; | |
98 children_map_.Resize(num_bits, false); | |
99 children_map_.SetMap(data->bitmap, num_bits / 32); | |
100 buffer_.reset(); | |
101 | |
102 DeleteChildren(); | |
103 } | |
104 | |
105 void ChildrenDeleter::ReadData(disk_cache::Addr address, int len) { | |
106 DCHECK(address.is_block_file()); | |
107 if (!backend_) | |
108 return Release(); | |
109 | |
110 disk_cache::File* file(backend_->File(address)); | |
111 if (!file) | |
112 return Release(); | |
113 | |
114 size_t file_offset = address.start_block() * address.BlockSize() + | |
115 disk_cache::kBlockHeaderSize; | |
116 | |
117 buffer_.reset(new char[len]); | |
118 bool completed; | |
119 if (!file->Read(buffer_.get(), len, file_offset, this, &completed)) | |
120 return Release(); | |
121 | |
122 if (completed) | |
123 OnFileIOComplete(len); | |
124 | |
125 // And wait until OnFileIOComplete gets called. | |
126 } | |
127 | |
128 void ChildrenDeleter::DeleteChildren() { | |
129 int child_id = 0; | |
130 if (!children_map_.FindNextSetBit(&child_id) || !backend_) { | |
131 // We are done. Just delete this object. | |
132 return Release(); | |
133 } | |
134 std::string child_name = GenerateChildName(name_, signature_, child_id); | |
135 backend_->SyncDoomEntry(child_name); | |
136 children_map_.Set(child_id, false); | |
137 | |
138 // Post a task to delete the next child. | |
139 base::MessageLoop::current()->PostTask( | |
140 FROM_HERE, base::Bind(&ChildrenDeleter::DeleteChildren, this)); | |
141 } | |
142 | |
143 // ----------------------------------------------------------------------- | |
144 | |
145 // Returns the NetLog event type corresponding to a SparseOperation. | |
146 net::NetLog::EventType GetSparseEventType( | |
147 disk_cache::SparseControl::SparseOperation operation) { | |
148 switch (operation) { | |
149 case disk_cache::SparseControl::kReadOperation: | |
150 return net::NetLog::TYPE_SPARSE_READ; | |
151 case disk_cache::SparseControl::kWriteOperation: | |
152 return net::NetLog::TYPE_SPARSE_WRITE; | |
153 case disk_cache::SparseControl::kGetRangeOperation: | |
154 return net::NetLog::TYPE_SPARSE_GET_RANGE; | |
155 default: | |
156 NOTREACHED(); | |
157 return net::NetLog::TYPE_CANCELLED; | |
158 } | |
159 } | |
160 | |
161 // Logs the end event for |operation| on a child entry. Range operations log | |
162 // no events for each child they search through. | |
163 void LogChildOperationEnd(const net::BoundNetLog& net_log, | |
164 disk_cache::SparseControl::SparseOperation operation, | |
165 int result) { | |
166 if (net_log.IsLogging()) { | |
167 net::NetLog::EventType event_type; | |
168 switch (operation) { | |
169 case disk_cache::SparseControl::kReadOperation: | |
170 event_type = net::NetLog::TYPE_SPARSE_READ_CHILD_DATA; | |
171 break; | |
172 case disk_cache::SparseControl::kWriteOperation: | |
173 event_type = net::NetLog::TYPE_SPARSE_WRITE_CHILD_DATA; | |
174 break; | |
175 case disk_cache::SparseControl::kGetRangeOperation: | |
176 return; | |
177 default: | |
178 NOTREACHED(); | |
179 return; | |
180 } | |
181 net_log.EndEventWithNetErrorCode(event_type, result); | |
182 } | |
183 } | |
184 | |
185 } // namespace. | |
186 | |
187 namespace disk_cache { | |
188 | |
189 SparseControl::SparseControl(EntryImpl* entry) | |
190 : entry_(entry), | |
191 child_(NULL), | |
192 operation_(kNoOperation), | |
193 pending_(false), | |
194 finished_(false), | |
195 init_(false), | |
196 range_found_(false), | |
197 abort_(false), | |
198 child_map_(child_data_.bitmap, kNumSparseBits, kNumSparseBits / 32), | |
199 offset_(0), | |
200 buf_len_(0), | |
201 child_offset_(0), | |
202 child_len_(0), | |
203 result_(0) { | |
204 memset(&sparse_header_, 0, sizeof(sparse_header_)); | |
205 memset(&child_data_, 0, sizeof(child_data_)); | |
206 } | |
207 | |
208 SparseControl::~SparseControl() { | |
209 if (child_) | |
210 CloseChild(); | |
211 if (init_) | |
212 WriteSparseData(); | |
213 } | |
214 | |
215 bool SparseControl::CouldBeSparse() const { | |
216 DCHECK(!init_); | |
217 | |
218 if (entry_->GetDataSize(kSparseData)) | |
219 return false; | |
220 | |
221 // We don't verify the data, just see if it could be there. | |
222 return (entry_->GetDataSize(kSparseIndex) != 0); | |
223 } | |
224 | |
225 int SparseControl::StartIO(SparseOperation op, int64 offset, net::IOBuffer* buf, | |
226 int buf_len, const CompletionCallback& callback) { | |
227 DCHECK(init_); | |
228 // We don't support simultaneous IO for sparse data. | |
229 if (operation_ != kNoOperation) | |
230 return net::ERR_CACHE_OPERATION_NOT_SUPPORTED; | |
231 | |
232 if (offset < 0 || buf_len < 0) | |
233 return net::ERR_INVALID_ARGUMENT; | |
234 | |
235 // We only support up to 64 GB. | |
236 if (offset + buf_len >= 0x1000000000LL || offset + buf_len < 0) | |
237 return net::ERR_CACHE_OPERATION_NOT_SUPPORTED; | |
238 | |
239 DCHECK(!user_buf_); | |
240 DCHECK(user_callback_.is_null()); | |
241 | |
242 if (!buf && (op == kReadOperation || op == kWriteOperation)) | |
243 return 0; | |
244 | |
245 // Copy the operation parameters. | |
246 operation_ = op; | |
247 offset_ = offset; | |
248 user_buf_ = buf ? new net::DrainableIOBuffer(buf, buf_len) : NULL; | |
249 buf_len_ = buf_len; | |
250 user_callback_ = callback; | |
251 | |
252 result_ = 0; | |
253 pending_ = false; | |
254 finished_ = false; | |
255 abort_ = false; | |
256 | |
257 if (entry_->net_log().IsLogging()) { | |
258 entry_->net_log().BeginEvent( | |
259 GetSparseEventType(operation_), | |
260 CreateNetLogSparseOperationCallback(offset_, buf_len_)); | |
261 } | |
262 DoChildrenIO(); | |
263 | |
264 if (!pending_) { | |
265 // Everything was done synchronously. | |
266 operation_ = kNoOperation; | |
267 user_buf_ = NULL; | |
268 user_callback_.Reset(); | |
269 return result_; | |
270 } | |
271 | |
272 return net::ERR_IO_PENDING; | |
273 } | |
274 | |
275 int SparseControl::GetAvailableRange(int64 offset, int len, int64* start) { | |
276 DCHECK(init_); | |
277 // We don't support simultaneous IO for sparse data. | |
278 if (operation_ != kNoOperation) | |
279 return net::ERR_CACHE_OPERATION_NOT_SUPPORTED; | |
280 | |
281 DCHECK(start); | |
282 | |
283 range_found_ = false; | |
284 int result = StartIO( | |
285 kGetRangeOperation, offset, NULL, len, CompletionCallback()); | |
286 if (range_found_) { | |
287 *start = offset_; | |
288 return result; | |
289 } | |
290 | |
291 // This is a failure. We want to return a valid start value in any case. | |
292 *start = offset; | |
293 return result < 0 ? result : 0; // Don't mask error codes to the caller. | |
294 } | |
295 | |
296 void SparseControl::CancelIO() { | |
297 if (operation_ == kNoOperation) | |
298 return; | |
299 abort_ = true; | |
300 } | |
301 | |
302 int SparseControl::ReadyToUse(const CompletionCallback& callback) { | |
303 if (!abort_) | |
304 return net::OK; | |
305 | |
306 // We'll grab another reference to keep this object alive because we just have | |
307 // one extra reference due to the pending IO operation itself, but we'll | |
308 // release that one before invoking user_callback_. | |
309 entry_->AddRef(); // Balanced in DoAbortCallbacks. | |
310 abort_callbacks_.push_back(callback); | |
311 return net::ERR_IO_PENDING; | |
312 } | |
313 | |
314 // Static | |
315 void SparseControl::DeleteChildren(EntryImpl* entry) { | |
316 DCHECK(entry->GetEntryFlags() & PARENT_ENTRY); | |
317 int data_len = entry->GetDataSize(kSparseIndex); | |
318 if (data_len < static_cast<int>(sizeof(SparseData)) || | |
319 entry->GetDataSize(kSparseData)) | |
320 return; | |
321 | |
322 int map_len = data_len - sizeof(SparseHeader); | |
323 if (map_len > kMaxMapSize || map_len % 4) | |
324 return; | |
325 | |
326 char* buffer; | |
327 Addr address; | |
328 entry->GetData(kSparseIndex, &buffer, &address); | |
329 if (!buffer && !address.is_initialized()) | |
330 return; | |
331 | |
332 entry->net_log().AddEvent(net::NetLog::TYPE_SPARSE_DELETE_CHILDREN); | |
333 | |
334 DCHECK(entry->backend_); | |
335 ChildrenDeleter* deleter = new ChildrenDeleter(entry->backend_.get(), | |
336 entry->GetKey()); | |
337 // The object will self destruct when finished. | |
338 deleter->AddRef(); | |
339 | |
340 if (buffer) { | |
341 base::MessageLoop::current()->PostTask( | |
342 FROM_HERE, | |
343 base::Bind(&ChildrenDeleter::Start, deleter, buffer, data_len)); | |
344 } else { | |
345 base::MessageLoop::current()->PostTask( | |
346 FROM_HERE, | |
347 base::Bind(&ChildrenDeleter::ReadData, deleter, address, data_len)); | |
348 } | |
349 } | |
350 | |
351 // ----------------------------------------------------------------------- | |
352 | |
353 int SparseControl::Init() { | |
354 DCHECK(!init_); | |
355 | |
356 // We should not have sparse data for the exposed entry. | |
357 if (entry_->GetDataSize(kSparseData)) | |
358 return net::ERR_CACHE_OPERATION_NOT_SUPPORTED; | |
359 | |
360 // Now see if there is something where we store our data. | |
361 int rv = net::OK; | |
362 int data_len = entry_->GetDataSize(kSparseIndex); | |
363 if (!data_len) { | |
364 rv = CreateSparseEntry(); | |
365 } else { | |
366 rv = OpenSparseEntry(data_len); | |
367 } | |
368 | |
369 if (rv == net::OK) | |
370 init_ = true; | |
371 return rv; | |
372 } | |
373 | |
374 // We are going to start using this entry to store sparse data, so we have to | |
375 // initialize our control info. | |
376 int SparseControl::CreateSparseEntry() { | |
377 if (CHILD_ENTRY & entry_->GetEntryFlags()) | |
378 return net::ERR_CACHE_OPERATION_NOT_SUPPORTED; | |
379 | |
380 memset(&sparse_header_, 0, sizeof(sparse_header_)); | |
381 sparse_header_.signature = Time::Now().ToInternalValue(); | |
382 sparse_header_.magic = kIndexMagic; | |
383 sparse_header_.parent_key_len = entry_->GetKey().size(); | |
384 children_map_.Resize(kNumSparseBits, true); | |
385 | |
386 // Save the header. The bitmap is saved in the destructor. | |
387 scoped_refptr<net::IOBuffer> buf( | |
388 new net::WrappedIOBuffer(reinterpret_cast<char*>(&sparse_header_))); | |
389 | |
390 int rv = entry_->WriteData(kSparseIndex, 0, buf.get(), sizeof(sparse_header_), | |
391 CompletionCallback(), false); | |
392 if (rv != sizeof(sparse_header_)) { | |
393 DLOG(ERROR) << "Unable to save sparse_header_"; | |
394 return net::ERR_CACHE_OPERATION_NOT_SUPPORTED; | |
395 } | |
396 | |
397 entry_->SetEntryFlags(PARENT_ENTRY); | |
398 return net::OK; | |
399 } | |
400 | |
401 // We are opening an entry from disk. Make sure that our control data is there. | |
402 int SparseControl::OpenSparseEntry(int data_len) { | |
403 if (data_len < static_cast<int>(sizeof(SparseData))) | |
404 return net::ERR_CACHE_OPERATION_NOT_SUPPORTED; | |
405 | |
406 if (entry_->GetDataSize(kSparseData)) | |
407 return net::ERR_CACHE_OPERATION_NOT_SUPPORTED; | |
408 | |
409 if (!(PARENT_ENTRY & entry_->GetEntryFlags())) | |
410 return net::ERR_CACHE_OPERATION_NOT_SUPPORTED; | |
411 | |
412 // Dont't go over board with the bitmap. 8 KB gives us offsets up to 64 GB. | |
413 int map_len = data_len - sizeof(sparse_header_); | |
414 if (map_len > kMaxMapSize || map_len % 4) | |
415 return net::ERR_CACHE_OPERATION_NOT_SUPPORTED; | |
416 | |
417 scoped_refptr<net::IOBuffer> buf( | |
418 new net::WrappedIOBuffer(reinterpret_cast<char*>(&sparse_header_))); | |
419 | |
420 // Read header. | |
421 int rv = entry_->ReadData(kSparseIndex, 0, buf.get(), sizeof(sparse_header_), | |
422 CompletionCallback()); | |
423 if (rv != static_cast<int>(sizeof(sparse_header_))) | |
424 return net::ERR_CACHE_READ_FAILURE; | |
425 | |
426 // The real validation should be performed by the caller. This is just to | |
427 // double check. | |
428 if (sparse_header_.magic != kIndexMagic || | |
429 sparse_header_.parent_key_len != | |
430 static_cast<int>(entry_->GetKey().size())) | |
431 return net::ERR_CACHE_OPERATION_NOT_SUPPORTED; | |
432 | |
433 // Read the actual bitmap. | |
434 buf = new net::IOBuffer(map_len); | |
435 rv = entry_->ReadData(kSparseIndex, sizeof(sparse_header_), buf.get(), | |
436 map_len, CompletionCallback()); | |
437 if (rv != map_len) | |
438 return net::ERR_CACHE_READ_FAILURE; | |
439 | |
440 // Grow the bitmap to the current size and copy the bits. | |
441 children_map_.Resize(map_len * 8, false); | |
442 children_map_.SetMap(reinterpret_cast<uint32*>(buf->data()), map_len); | |
443 return net::OK; | |
444 } | |
445 | |
446 bool SparseControl::OpenChild() { | |
447 DCHECK_GE(result_, 0); | |
448 | |
449 std::string key = GenerateChildKey(); | |
450 if (child_) { | |
451 // Keep using the same child or open another one?. | |
452 if (key == child_->GetKey()) | |
453 return true; | |
454 CloseChild(); | |
455 } | |
456 | |
457 // See if we are tracking this child. | |
458 if (!ChildPresent()) | |
459 return ContinueWithoutChild(key); | |
460 | |
461 if (!entry_->backend_) | |
462 return false; | |
463 | |
464 child_ = entry_->backend_->OpenEntryImpl(key); | |
465 if (!child_) | |
466 return ContinueWithoutChild(key); | |
467 | |
468 EntryImpl* child = static_cast<EntryImpl*>(child_); | |
469 if (!(CHILD_ENTRY & child->GetEntryFlags()) || | |
470 child->GetDataSize(kSparseIndex) < | |
471 static_cast<int>(sizeof(child_data_))) | |
472 return KillChildAndContinue(key, false); | |
473 | |
474 scoped_refptr<net::WrappedIOBuffer> buf( | |
475 new net::WrappedIOBuffer(reinterpret_cast<char*>(&child_data_))); | |
476 | |
477 // Read signature. | |
478 int rv = child_->ReadData(kSparseIndex, 0, buf.get(), sizeof(child_data_), | |
479 CompletionCallback()); | |
480 if (rv != sizeof(child_data_)) | |
481 return KillChildAndContinue(key, true); // This is a fatal failure. | |
482 | |
483 if (child_data_.header.signature != sparse_header_.signature || | |
484 child_data_.header.magic != kIndexMagic) | |
485 return KillChildAndContinue(key, false); | |
486 | |
487 if (child_data_.header.last_block_len < 0 || | |
488 child_data_.header.last_block_len > kBlockSize) { | |
489 // Make sure these values are always within range. | |
490 child_data_.header.last_block_len = 0; | |
491 child_data_.header.last_block = -1; | |
492 } | |
493 | |
494 return true; | |
495 } | |
496 | |
497 void SparseControl::CloseChild() { | |
498 scoped_refptr<net::WrappedIOBuffer> buf( | |
499 new net::WrappedIOBuffer(reinterpret_cast<char*>(&child_data_))); | |
500 | |
501 // Save the allocation bitmap before closing the child entry. | |
502 int rv = child_->WriteData(kSparseIndex, 0, buf.get(), sizeof(child_data_), | |
503 CompletionCallback(), | |
504 false); | |
505 if (rv != sizeof(child_data_)) | |
506 DLOG(ERROR) << "Failed to save child data"; | |
507 child_->Release(); | |
508 child_ = NULL; | |
509 } | |
510 | |
511 // We were not able to open this child; see what we can do. | |
512 bool SparseControl::ContinueWithoutChild(const std::string& key) { | |
513 if (kReadOperation == operation_) | |
514 return false; | |
515 if (kGetRangeOperation == operation_) | |
516 return true; | |
517 | |
518 if (!entry_->backend_) | |
519 return false; | |
520 | |
521 child_ = entry_->backend_->CreateEntryImpl(key); | |
522 if (!child_) { | |
523 child_ = NULL; | |
524 result_ = net::ERR_CACHE_READ_FAILURE; | |
525 return false; | |
526 } | |
527 // Write signature. | |
528 InitChildData(); | |
529 return true; | |
530 } | |
531 | |
532 void SparseControl::WriteSparseData() { | |
533 scoped_refptr<net::IOBuffer> buf(new net::WrappedIOBuffer( | |
534 reinterpret_cast<const char*>(children_map_.GetMap()))); | |
535 | |
536 int len = children_map_.ArraySize() * 4; | |
537 int rv = entry_->WriteData(kSparseIndex, sizeof(sparse_header_), buf.get(), | |
538 len, CompletionCallback(), false); | |
539 if (rv != len) { | |
540 DLOG(ERROR) << "Unable to save sparse map"; | |
541 } | |
542 } | |
543 | |
544 bool SparseControl::DoChildIO() { | |
545 finished_ = true; | |
546 if (!buf_len_ || result_ < 0) | |
547 return false; | |
548 | |
549 if (!OpenChild()) | |
550 return false; | |
551 | |
552 if (!VerifyRange()) | |
553 return false; | |
554 | |
555 // We have more work to do. Let's not trigger a callback to the caller. | |
556 finished_ = false; | |
557 CompletionCallback callback; | |
558 if (!user_callback_.is_null()) { | |
559 callback = | |
560 base::Bind(&SparseControl::OnChildIOCompleted, base::Unretained(this)); | |
561 } | |
562 | |
563 int rv = 0; | |
564 switch (operation_) { | |
565 case kReadOperation: | |
566 if (entry_->net_log().IsLogging()) { | |
567 entry_->net_log().BeginEvent( | |
568 net::NetLog::TYPE_SPARSE_READ_CHILD_DATA, | |
569 CreateNetLogSparseReadWriteCallback(child_->net_log().source(), | |
570 child_len_)); | |
571 } | |
572 rv = child_->ReadDataImpl(kSparseData, child_offset_, user_buf_.get(), | |
573 child_len_, callback); | |
574 break; | |
575 case kWriteOperation: | |
576 if (entry_->net_log().IsLogging()) { | |
577 entry_->net_log().BeginEvent( | |
578 net::NetLog::TYPE_SPARSE_WRITE_CHILD_DATA, | |
579 CreateNetLogSparseReadWriteCallback(child_->net_log().source(), | |
580 child_len_)); | |
581 } | |
582 rv = child_->WriteDataImpl(kSparseData, child_offset_, user_buf_.get(), | |
583 child_len_, callback, false); | |
584 break; | |
585 case kGetRangeOperation: | |
586 rv = DoGetAvailableRange(); | |
587 break; | |
588 default: | |
589 NOTREACHED(); | |
590 } | |
591 | |
592 if (rv == net::ERR_IO_PENDING) { | |
593 if (!pending_) { | |
594 pending_ = true; | |
595 // The child will protect himself against closing the entry while IO is in | |
596 // progress. However, this entry can still be closed, and that would not | |
597 // be a good thing for us, so we increase the refcount until we're | |
598 // finished doing sparse stuff. | |
599 entry_->AddRef(); // Balanced in DoUserCallback. | |
600 } | |
601 return false; | |
602 } | |
603 if (!rv) | |
604 return false; | |
605 | |
606 DoChildIOCompleted(rv); | |
607 return true; | |
608 } | |
609 | |
610 void SparseControl::DoChildIOCompleted(int result) { | |
611 LogChildOperationEnd(entry_->net_log(), operation_, result); | |
612 if (result < 0) { | |
613 // We fail the whole operation if we encounter an error. | |
614 result_ = result; | |
615 return; | |
616 } | |
617 | |
618 UpdateRange(result); | |
619 | |
620 result_ += result; | |
621 offset_ += result; | |
622 buf_len_ -= result; | |
623 | |
624 // We'll be reusing the user provided buffer for the next chunk. | |
625 if (buf_len_ && user_buf_) | |
626 user_buf_->DidConsume(result); | |
627 } | |
628 | |
629 std::string SparseControl::GenerateChildKey() { | |
630 return GenerateChildName(entry_->GetKey(), sparse_header_.signature, | |
631 offset_ >> 20); | |
632 } | |
633 | |
634 // We are deleting the child because something went wrong. | |
635 bool SparseControl::KillChildAndContinue(const std::string& key, bool fatal) { | |
636 SetChildBit(false); | |
637 child_->DoomImpl(); | |
638 child_->Release(); | |
639 child_ = NULL; | |
640 if (fatal) { | |
641 result_ = net::ERR_CACHE_READ_FAILURE; | |
642 return false; | |
643 } | |
644 return ContinueWithoutChild(key); | |
645 } | |
646 | |
647 bool SparseControl::ChildPresent() { | |
648 int child_bit = static_cast<int>(offset_ >> 20); | |
649 if (children_map_.Size() <= child_bit) | |
650 return false; | |
651 | |
652 return children_map_.Get(child_bit); | |
653 } | |
654 | |
655 void SparseControl::SetChildBit(bool value) { | |
656 int child_bit = static_cast<int>(offset_ >> 20); | |
657 | |
658 // We may have to increase the bitmap of child entries. | |
659 if (children_map_.Size() <= child_bit) | |
660 children_map_.Resize(Bitmap::RequiredArraySize(child_bit + 1) * 32, true); | |
661 | |
662 children_map_.Set(child_bit, value); | |
663 } | |
664 | |
665 bool SparseControl::VerifyRange() { | |
666 DCHECK_GE(result_, 0); | |
667 | |
668 child_offset_ = static_cast<int>(offset_) & (kMaxEntrySize - 1); | |
669 child_len_ = std::min(buf_len_, kMaxEntrySize - child_offset_); | |
670 | |
671 // We can write to (or get info from) anywhere in this child. | |
672 if (operation_ != kReadOperation) | |
673 return true; | |
674 | |
675 // Check that there are no holes in this range. | |
676 int last_bit = (child_offset_ + child_len_ + 1023) >> 10; | |
677 int start = child_offset_ >> 10; | |
678 if (child_map_.FindNextBit(&start, last_bit, false)) { | |
679 // Something is not here. | |
680 DCHECK_GE(child_data_.header.last_block_len, 0); | |
681 DCHECK_LT(child_data_.header.last_block_len, kMaxEntrySize); | |
682 int partial_block_len = PartialBlockLength(start); | |
683 if (start == child_offset_ >> 10) { | |
684 // It looks like we don't have anything. | |
685 if (partial_block_len <= (child_offset_ & (kBlockSize - 1))) | |
686 return false; | |
687 } | |
688 | |
689 // We have the first part. | |
690 child_len_ = (start << 10) - child_offset_; | |
691 if (partial_block_len) { | |
692 // We may have a few extra bytes. | |
693 child_len_ = std::min(child_len_ + partial_block_len, buf_len_); | |
694 } | |
695 // There is no need to read more after this one. | |
696 buf_len_ = child_len_; | |
697 } | |
698 return true; | |
699 } | |
700 | |
701 void SparseControl::UpdateRange(int result) { | |
702 if (result <= 0 || operation_ != kWriteOperation) | |
703 return; | |
704 | |
705 DCHECK_GE(child_data_.header.last_block_len, 0); | |
706 DCHECK_LT(child_data_.header.last_block_len, kMaxEntrySize); | |
707 | |
708 // Write the bitmap. | |
709 int first_bit = child_offset_ >> 10; | |
710 int block_offset = child_offset_ & (kBlockSize - 1); | |
711 if (block_offset && (child_data_.header.last_block != first_bit || | |
712 child_data_.header.last_block_len < block_offset)) { | |
713 // The first block is not completely filled; ignore it. | |
714 first_bit++; | |
715 } | |
716 | |
717 int last_bit = (child_offset_ + result) >> 10; | |
718 block_offset = (child_offset_ + result) & (kBlockSize - 1); | |
719 | |
720 // This condition will hit with the following criteria: | |
721 // 1. The first byte doesn't follow the last write. | |
722 // 2. The first byte is in the middle of a block. | |
723 // 3. The first byte and the last byte are in the same block. | |
724 if (first_bit > last_bit) | |
725 return; | |
726 | |
727 if (block_offset && !child_map_.Get(last_bit)) { | |
728 // The last block is not completely filled; save it for later. | |
729 child_data_.header.last_block = last_bit; | |
730 child_data_.header.last_block_len = block_offset; | |
731 } else { | |
732 child_data_.header.last_block = -1; | |
733 } | |
734 | |
735 child_map_.SetRange(first_bit, last_bit, true); | |
736 } | |
737 | |
738 int SparseControl::PartialBlockLength(int block_index) const { | |
739 if (block_index == child_data_.header.last_block) | |
740 return child_data_.header.last_block_len; | |
741 | |
742 // This may be the last stored index. | |
743 int entry_len = child_->GetDataSize(kSparseData); | |
744 if (block_index == entry_len >> 10) | |
745 return entry_len & (kBlockSize - 1); | |
746 | |
747 // This is really empty. | |
748 return 0; | |
749 } | |
750 | |
751 void SparseControl::InitChildData() { | |
752 // We know the real type of child_. | |
753 EntryImpl* child = static_cast<EntryImpl*>(child_); | |
754 child->SetEntryFlags(CHILD_ENTRY); | |
755 | |
756 memset(&child_data_, 0, sizeof(child_data_)); | |
757 child_data_.header = sparse_header_; | |
758 | |
759 scoped_refptr<net::WrappedIOBuffer> buf( | |
760 new net::WrappedIOBuffer(reinterpret_cast<char*>(&child_data_))); | |
761 | |
762 int rv = child_->WriteData(kSparseIndex, 0, buf.get(), sizeof(child_data_), | |
763 CompletionCallback(), false); | |
764 if (rv != sizeof(child_data_)) | |
765 DLOG(ERROR) << "Failed to save child data"; | |
766 SetChildBit(true); | |
767 } | |
768 | |
769 int SparseControl::DoGetAvailableRange() { | |
770 if (!child_) | |
771 return child_len_; // Move on to the next child. | |
772 | |
773 // Check that there are no holes in this range. | |
774 int last_bit = (child_offset_ + child_len_ + 1023) >> 10; | |
775 int start = child_offset_ >> 10; | |
776 int partial_start_bytes = PartialBlockLength(start); | |
777 int found = start; | |
778 int bits_found = child_map_.FindBits(&found, last_bit, true); | |
779 | |
780 // We don't care if there is a partial block in the middle of the range. | |
781 int block_offset = child_offset_ & (kBlockSize - 1); | |
782 if (!bits_found && partial_start_bytes <= block_offset) | |
783 return child_len_; | |
784 | |
785 // We are done. Just break the loop and reset result_ to our real result. | |
786 range_found_ = true; | |
787 | |
788 // found now points to the first 1. Lets see if we have zeros before it. | |
789 int empty_start = std::max((found << 10) - child_offset_, 0); | |
790 | |
791 int bytes_found = bits_found << 10; | |
792 bytes_found += PartialBlockLength(found + bits_found); | |
793 | |
794 if (start == found) | |
795 bytes_found -= block_offset; | |
796 | |
797 // If the user is searching past the end of this child, bits_found is the | |
798 // right result; otherwise, we have some empty space at the start of this | |
799 // query that we have to subtract from the range that we searched. | |
800 result_ = std::min(bytes_found, child_len_ - empty_start); | |
801 | |
802 if (!bits_found) { | |
803 result_ = std::min(partial_start_bytes - block_offset, child_len_); | |
804 empty_start = 0; | |
805 } | |
806 | |
807 // Only update offset_ when this query found zeros at the start. | |
808 if (empty_start) | |
809 offset_ += empty_start; | |
810 | |
811 // This will actually break the loop. | |
812 buf_len_ = 0; | |
813 return 0; | |
814 } | |
815 | |
816 void SparseControl::DoUserCallback() { | |
817 DCHECK(!user_callback_.is_null()); | |
818 CompletionCallback cb = user_callback_; | |
819 user_callback_.Reset(); | |
820 user_buf_ = NULL; | |
821 pending_ = false; | |
822 operation_ = kNoOperation; | |
823 int rv = result_; | |
824 entry_->Release(); // Don't touch object after this line. | |
825 cb.Run(rv); | |
826 } | |
827 | |
828 void SparseControl::DoAbortCallbacks() { | |
829 for (size_t i = 0; i < abort_callbacks_.size(); i++) { | |
830 // Releasing all references to entry_ may result in the destruction of this | |
831 // object so we should not be touching it after the last Release(). | |
832 CompletionCallback cb = abort_callbacks_[i]; | |
833 if (i == abort_callbacks_.size() - 1) | |
834 abort_callbacks_.clear(); | |
835 | |
836 entry_->Release(); // Don't touch object after this line. | |
837 cb.Run(net::OK); | |
838 } | |
839 } | |
840 | |
841 void SparseControl::OnChildIOCompleted(int result) { | |
842 DCHECK_NE(net::ERR_IO_PENDING, result); | |
843 DoChildIOCompleted(result); | |
844 | |
845 if (abort_) { | |
846 // We'll return the current result of the operation, which may be less than | |
847 // the bytes to read or write, but the user cancelled the operation. | |
848 abort_ = false; | |
849 if (entry_->net_log().IsLogging()) { | |
850 entry_->net_log().AddEvent(net::NetLog::TYPE_CANCELLED); | |
851 entry_->net_log().EndEvent(GetSparseEventType(operation_)); | |
852 } | |
853 // We have an indirect reference to this object for every callback so if | |
854 // there is only one callback, we may delete this object before reaching | |
855 // DoAbortCallbacks. | |
856 bool has_abort_callbacks = !abort_callbacks_.empty(); | |
857 DoUserCallback(); | |
858 if (has_abort_callbacks) | |
859 DoAbortCallbacks(); | |
860 return; | |
861 } | |
862 | |
863 // We are running a callback from the message loop. It's time to restart what | |
864 // we were doing before. | |
865 DoChildrenIO(); | |
866 } | |
867 | |
868 } // namespace disk_cache | |
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