1 // Copyright (c) 2013 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/simple/simple_index.h"
6
7 #include <algorithm>
8 #include <limits>
9 #include <string>
10 #include <utility>
11
12 #include "base/bind.h"
13 #include "base/bind_helpers.h"
14 #include "base/files/file_enumerator.h"
15 #include "base/files/file_util.h"
16 #include "base/logging.h"
17 #include "base/message_loop/message_loop.h"
18 #include "base/metrics/field_trial.h"
19 #include "base/pickle.h"
20 #include "base/strings/string_number_conversions.h"
21 #include "base/strings/string_tokenizer.h"
22 #include "base/task_runner.h"
23 #include "base/threading/worker_pool.h"
24 #include "base/time/time.h"
25 #include "net/base/net_errors.h"
26 #include "net/disk_cache/simple/simple_entry_format.h"
27 #include "net/disk_cache/simple/simple_histogram_macros.h"
28 #include "net/disk_cache/simple/simple_index_delegate.h"
29 #include "net/disk_cache/simple/simple_index_file.h"
30 #include "net/disk_cache/simple/simple_synchronous_entry.h"
31 #include "net/disk_cache/simple/simple_util.h"
32
33 #if defined(OS_POSIX)
34 #include <sys/stat.h>
35 #include <sys/time.h>
36 #endif
37
38 namespace {
39
40 // How many milliseconds we delay writing the index to disk since the last cache
41 // operation has happened.
42 const int kWriteToDiskDelayMSecs = 20000;
43 const int kWriteToDiskOnBackgroundDelayMSecs = 100;
44
45 // Divides the cache space into this amount of parts to evict when only one part
46 // is left.
47 const uint32 kEvictionMarginDivisor = 20;
48
49 const uint32 kBytesInKb = 1024;
50
51 // Utility class used for timestamp comparisons in entry metadata while sorting.
52 class CompareHashesForTimestamp {
53 typedef disk_cache::SimpleIndex SimpleIndex;
54 typedef disk_cache::SimpleIndex::EntrySet EntrySet;
55 public:
56 explicit CompareHashesForTimestamp(const EntrySet& set);
57
58 bool operator()(uint64 hash1, uint64 hash2);
59 private:
60 const EntrySet& entry_set_;
61 };
62
CompareHashesForTimestamp(const EntrySet & set)63 CompareHashesForTimestamp::CompareHashesForTimestamp(const EntrySet& set)
64 : entry_set_(set) {
65 }
66
operator ()(uint64 hash1,uint64 hash2)67 bool CompareHashesForTimestamp::operator()(uint64 hash1, uint64 hash2) {
68 EntrySet::const_iterator it1 = entry_set_.find(hash1);
69 DCHECK(it1 != entry_set_.end());
70 EntrySet::const_iterator it2 = entry_set_.find(hash2);
71 DCHECK(it2 != entry_set_.end());
72 return it1->second.GetLastUsedTime() < it2->second.GetLastUsedTime();
73 }
74
75 } // namespace
76
77 namespace disk_cache {
78
EntryMetadata()79 EntryMetadata::EntryMetadata()
80 : last_used_time_seconds_since_epoch_(0),
81 entry_size_(0) {
82 }
83
EntryMetadata(base::Time last_used_time,int entry_size)84 EntryMetadata::EntryMetadata(base::Time last_used_time, int entry_size)
85 : last_used_time_seconds_since_epoch_(0),
86 entry_size_(entry_size) {
87 SetLastUsedTime(last_used_time);
88 }
89
GetLastUsedTime() const90 base::Time EntryMetadata::GetLastUsedTime() const {
91 // Preserve nullity.
92 if (last_used_time_seconds_since_epoch_ == 0)
93 return base::Time();
94
95 return base::Time::UnixEpoch() +
96 base::TimeDelta::FromSeconds(last_used_time_seconds_since_epoch_);
97 }
98
SetLastUsedTime(const base::Time & last_used_time)99 void EntryMetadata::SetLastUsedTime(const base::Time& last_used_time) {
100 // Preserve nullity.
101 if (last_used_time.is_null()) {
102 last_used_time_seconds_since_epoch_ = 0;
103 return;
104 }
105
106 const base::TimeDelta since_unix_epoch =
107 last_used_time - base::Time::UnixEpoch();
108 const int64 seconds_since_unix_epoch = since_unix_epoch.InSeconds();
109 DCHECK_LE(implicit_cast<int64>(std::numeric_limits<uint32>::min()),
110 seconds_since_unix_epoch);
111 DCHECK_GE(implicit_cast<int64>(std::numeric_limits<uint32>::max()),
112 seconds_since_unix_epoch);
113
114 last_used_time_seconds_since_epoch_ = seconds_since_unix_epoch;
115 // Avoid accidental nullity.
116 if (last_used_time_seconds_since_epoch_ == 0)
117 last_used_time_seconds_since_epoch_ = 1;
118 }
119
Serialize(Pickle * pickle) const120 void EntryMetadata::Serialize(Pickle* pickle) const {
121 DCHECK(pickle);
122 int64 internal_last_used_time = GetLastUsedTime().ToInternalValue();
123 pickle->WriteInt64(internal_last_used_time);
124 pickle->WriteUInt64(entry_size_);
125 }
126
Deserialize(PickleIterator * it)127 bool EntryMetadata::Deserialize(PickleIterator* it) {
128 DCHECK(it);
129 int64 tmp_last_used_time;
130 uint64 tmp_entry_size;
131 if (!it->ReadInt64(&tmp_last_used_time) || !it->ReadUInt64(&tmp_entry_size))
132 return false;
133 SetLastUsedTime(base::Time::FromInternalValue(tmp_last_used_time));
134 entry_size_ = tmp_entry_size;
135 return true;
136 }
137
SimpleIndex(const scoped_refptr<base::SingleThreadTaskRunner> & io_thread,SimpleIndexDelegate * delegate,net::CacheType cache_type,scoped_ptr<SimpleIndexFile> index_file)138 SimpleIndex::SimpleIndex(
139 const scoped_refptr<base::SingleThreadTaskRunner>& io_thread,
140 SimpleIndexDelegate* delegate,
141 net::CacheType cache_type,
142 scoped_ptr<SimpleIndexFile> index_file)
143 : delegate_(delegate),
144 cache_type_(cache_type),
145 cache_size_(0),
146 max_size_(0),
147 high_watermark_(0),
148 low_watermark_(0),
149 eviction_in_progress_(false),
150 initialized_(false),
151 index_file_(index_file.Pass()),
152 io_thread_(io_thread),
153 // Creating the callback once so it is reused every time
154 // write_to_disk_timer_.Start() is called.
155 write_to_disk_cb_(base::Bind(&SimpleIndex::WriteToDisk, AsWeakPtr())),
156 app_on_background_(false) {
157 }
158
~SimpleIndex()159 SimpleIndex::~SimpleIndex() {
160 DCHECK(io_thread_checker_.CalledOnValidThread());
161
162 // Fail all callbacks waiting for the index to come up.
163 for (CallbackList::iterator it = to_run_when_initialized_.begin(),
164 end = to_run_when_initialized_.end(); it != end; ++it) {
165 it->Run(net::ERR_ABORTED);
166 }
167 }
168
Initialize(base::Time cache_mtime)169 void SimpleIndex::Initialize(base::Time cache_mtime) {
170 DCHECK(io_thread_checker_.CalledOnValidThread());
171
172 #if defined(OS_ANDROID)
173 if (base::android::IsVMInitialized()) {
174 app_status_listener_.reset(new base::android::ApplicationStatusListener(
175 base::Bind(&SimpleIndex::OnApplicationStateChange, AsWeakPtr())));
176 }
177 #endif
178
179 SimpleIndexLoadResult* load_result = new SimpleIndexLoadResult();
180 scoped_ptr<SimpleIndexLoadResult> load_result_scoped(load_result);
181 base::Closure reply = base::Bind(
182 &SimpleIndex::MergeInitializingSet,
183 AsWeakPtr(),
184 base::Passed(&load_result_scoped));
185 index_file_->LoadIndexEntries(cache_mtime, reply, load_result);
186 }
187
SetMaxSize(int max_bytes)188 bool SimpleIndex::SetMaxSize(int max_bytes) {
189 if (max_bytes < 0)
190 return false;
191
192 // Zero size means use the default.
193 if (!max_bytes)
194 return true;
195
196 max_size_ = max_bytes;
197 high_watermark_ = max_size_ - max_size_ / kEvictionMarginDivisor;
198 low_watermark_ = max_size_ - 2 * (max_size_ / kEvictionMarginDivisor);
199 return true;
200 }
201
ExecuteWhenReady(const net::CompletionCallback & task)202 int SimpleIndex::ExecuteWhenReady(const net::CompletionCallback& task) {
203 DCHECK(io_thread_checker_.CalledOnValidThread());
204 if (initialized_)
205 io_thread_->PostTask(FROM_HERE, base::Bind(task, net::OK));
206 else
207 to_run_when_initialized_.push_back(task);
208 return net::ERR_IO_PENDING;
209 }
210
GetEntriesBetween(base::Time initial_time,base::Time end_time)211 scoped_ptr<SimpleIndex::HashList> SimpleIndex::GetEntriesBetween(
212 base::Time initial_time, base::Time end_time) {
213 DCHECK_EQ(true, initialized_);
214
215 if (!initial_time.is_null())
216 initial_time -= EntryMetadata::GetLowerEpsilonForTimeComparisons();
217 if (end_time.is_null())
218 end_time = base::Time::Max();
219 else
220 end_time += EntryMetadata::GetUpperEpsilonForTimeComparisons();
221 const base::Time extended_end_time =
222 end_time.is_null() ? base::Time::Max() : end_time;
223 DCHECK(extended_end_time >= initial_time);
224 scoped_ptr<HashList> ret_hashes(new HashList());
225 for (EntrySet::iterator it = entries_set_.begin(), end = entries_set_.end();
226 it != end; ++it) {
227 EntryMetadata& metadata = it->second;
228 base::Time entry_time = metadata.GetLastUsedTime();
229 if (initial_time <= entry_time && entry_time < extended_end_time)
230 ret_hashes->push_back(it->first);
231 }
232 return ret_hashes.Pass();
233 }
234
GetAllHashes()235 scoped_ptr<SimpleIndex::HashList> SimpleIndex::GetAllHashes() {
236 return GetEntriesBetween(base::Time(), base::Time());
237 }
238
GetEntryCount() const239 int32 SimpleIndex::GetEntryCount() const {
240 // TODO(pasko): return a meaningful initial estimate before initialized.
241 return entries_set_.size();
242 }
243
Insert(uint64 entry_hash)244 void SimpleIndex::Insert(uint64 entry_hash) {
245 DCHECK(io_thread_checker_.CalledOnValidThread());
246 // Upon insert we don't know yet the size of the entry.
247 // It will be updated later when the SimpleEntryImpl finishes opening or
248 // creating the new entry, and then UpdateEntrySize will be called.
249 InsertInEntrySet(
250 entry_hash, EntryMetadata(base::Time::Now(), 0), &entries_set_);
251 if (!initialized_)
252 removed_entries_.erase(entry_hash);
253 PostponeWritingToDisk();
254 }
255
Remove(uint64 entry_hash)256 void SimpleIndex::Remove(uint64 entry_hash) {
257 DCHECK(io_thread_checker_.CalledOnValidThread());
258 EntrySet::iterator it = entries_set_.find(entry_hash);
259 if (it != entries_set_.end()) {
260 UpdateEntryIteratorSize(&it, 0);
261 entries_set_.erase(it);
262 }
263
264 if (!initialized_)
265 removed_entries_.insert(entry_hash);
266 PostponeWritingToDisk();
267 }
268
Has(uint64 hash) const269 bool SimpleIndex::Has(uint64 hash) const {
270 DCHECK(io_thread_checker_.CalledOnValidThread());
271 // If not initialized, always return true, forcing it to go to the disk.
272 return !initialized_ || entries_set_.count(hash) > 0;
273 }
274
UseIfExists(uint64 entry_hash)275 bool SimpleIndex::UseIfExists(uint64 entry_hash) {
276 DCHECK(io_thread_checker_.CalledOnValidThread());
277 // Always update the last used time, even if it is during initialization.
278 // It will be merged later.
279 EntrySet::iterator it = entries_set_.find(entry_hash);
280 if (it == entries_set_.end())
281 // If not initialized, always return true, forcing it to go to the disk.
282 return !initialized_;
283 it->second.SetLastUsedTime(base::Time::Now());
284 PostponeWritingToDisk();
285 return true;
286 }
287
StartEvictionIfNeeded()288 void SimpleIndex::StartEvictionIfNeeded() {
289 DCHECK(io_thread_checker_.CalledOnValidThread());
290 if (eviction_in_progress_ || cache_size_ <= high_watermark_)
291 return;
292 // Take all live key hashes from the index and sort them by time.
293 eviction_in_progress_ = true;
294 eviction_start_time_ = base::TimeTicks::Now();
295 SIMPLE_CACHE_UMA(MEMORY_KB,
296 "Eviction.CacheSizeOnStart2", cache_type_,
297 cache_size_ / kBytesInKb);
298 SIMPLE_CACHE_UMA(MEMORY_KB,
299 "Eviction.MaxCacheSizeOnStart2", cache_type_,
300 max_size_ / kBytesInKb);
301 std::vector<uint64> entry_hashes;
302 entry_hashes.reserve(entries_set_.size());
303 for (EntrySet::const_iterator it = entries_set_.begin(),
304 end = entries_set_.end(); it != end; ++it) {
305 entry_hashes.push_back(it->first);
306 }
307 std::sort(entry_hashes.begin(), entry_hashes.end(),
308 CompareHashesForTimestamp(entries_set_));
309
310 // Remove as many entries from the index to get below |low_watermark_|.
311 std::vector<uint64>::iterator it = entry_hashes.begin();
312 uint64 evicted_so_far_size = 0;
313 while (evicted_so_far_size < cache_size_ - low_watermark_) {
314 DCHECK(it != entry_hashes.end());
315 EntrySet::iterator found_meta = entries_set_.find(*it);
316 DCHECK(found_meta != entries_set_.end());
317 uint64 to_evict_size = found_meta->second.GetEntrySize();
318 evicted_so_far_size += to_evict_size;
319 ++it;
320 }
321
322 // Take out the rest of hashes from the eviction list.
323 entry_hashes.erase(it, entry_hashes.end());
324 SIMPLE_CACHE_UMA(COUNTS,
325 "Eviction.EntryCount", cache_type_, entry_hashes.size());
326 SIMPLE_CACHE_UMA(TIMES,
327 "Eviction.TimeToSelectEntries", cache_type_,
328 base::TimeTicks::Now() - eviction_start_time_);
329 SIMPLE_CACHE_UMA(MEMORY_KB,
330 "Eviction.SizeOfEvicted2", cache_type_,
331 evicted_so_far_size / kBytesInKb);
332
333 delegate_->DoomEntries(&entry_hashes, base::Bind(&SimpleIndex::EvictionDone,
334 AsWeakPtr()));
335 }
336
UpdateEntrySize(uint64 entry_hash,int entry_size)337 bool SimpleIndex::UpdateEntrySize(uint64 entry_hash, int entry_size) {
338 DCHECK(io_thread_checker_.CalledOnValidThread());
339 EntrySet::iterator it = entries_set_.find(entry_hash);
340 if (it == entries_set_.end())
341 return false;
342
343 UpdateEntryIteratorSize(&it, entry_size);
344 PostponeWritingToDisk();
345 StartEvictionIfNeeded();
346 return true;
347 }
348
EvictionDone(int result)349 void SimpleIndex::EvictionDone(int result) {
350 DCHECK(io_thread_checker_.CalledOnValidThread());
351
352 // Ignore the result of eviction. We did our best.
353 eviction_in_progress_ = false;
354 SIMPLE_CACHE_UMA(BOOLEAN, "Eviction.Result", cache_type_, result == net::OK);
355 SIMPLE_CACHE_UMA(TIMES,
356 "Eviction.TimeToDone", cache_type_,
357 base::TimeTicks::Now() - eviction_start_time_);
358 SIMPLE_CACHE_UMA(MEMORY_KB,
359 "Eviction.SizeWhenDone2", cache_type_,
360 cache_size_ / kBytesInKb);
361 }
362
363 // static
InsertInEntrySet(uint64 entry_hash,const disk_cache::EntryMetadata & entry_metadata,EntrySet * entry_set)364 void SimpleIndex::InsertInEntrySet(
365 uint64 entry_hash,
366 const disk_cache::EntryMetadata& entry_metadata,
367 EntrySet* entry_set) {
368 DCHECK(entry_set);
369 entry_set->insert(std::make_pair(entry_hash, entry_metadata));
370 }
371
PostponeWritingToDisk()372 void SimpleIndex::PostponeWritingToDisk() {
373 if (!initialized_)
374 return;
375 const int delay = app_on_background_ ? kWriteToDiskOnBackgroundDelayMSecs
376 : kWriteToDiskDelayMSecs;
377 // If the timer is already active, Start() will just Reset it, postponing it.
378 write_to_disk_timer_.Start(
379 FROM_HERE, base::TimeDelta::FromMilliseconds(delay), write_to_disk_cb_);
380 }
381
UpdateEntryIteratorSize(EntrySet::iterator * it,int entry_size)382 void SimpleIndex::UpdateEntryIteratorSize(EntrySet::iterator* it,
383 int entry_size) {
384 // Update the total cache size with the new entry size.
385 DCHECK(io_thread_checker_.CalledOnValidThread());
386 DCHECK_GE(cache_size_, implicit_cast<uint64>((*it)->second.GetEntrySize()));
387 cache_size_ -= (*it)->second.GetEntrySize();
388 cache_size_ += entry_size;
389 (*it)->second.SetEntrySize(entry_size);
390 }
391
MergeInitializingSet(scoped_ptr<SimpleIndexLoadResult> load_result)392 void SimpleIndex::MergeInitializingSet(
393 scoped_ptr<SimpleIndexLoadResult> load_result) {
394 DCHECK(io_thread_checker_.CalledOnValidThread());
395 DCHECK(load_result->did_load);
396
397 EntrySet* index_file_entries = &load_result->entries;
398
399 for (base::hash_set<uint64>::const_iterator it = removed_entries_.begin();
400 it != removed_entries_.end(); ++it) {
401 index_file_entries->erase(*it);
402 }
403 removed_entries_.clear();
404
405 for (EntrySet::const_iterator it = entries_set_.begin();
406 it != entries_set_.end(); ++it) {
407 const uint64 entry_hash = it->first;
408 std::pair<EntrySet::iterator, bool> insert_result =
409 index_file_entries->insert(EntrySet::value_type(entry_hash,
410 EntryMetadata()));
411 EntrySet::iterator& possibly_inserted_entry = insert_result.first;
412 possibly_inserted_entry->second = it->second;
413 }
414
415 uint64 merged_cache_size = 0;
416 for (EntrySet::iterator it = index_file_entries->begin();
417 it != index_file_entries->end(); ++it) {
418 merged_cache_size += it->second.GetEntrySize();
419 }
420
421 entries_set_.swap(*index_file_entries);
422 cache_size_ = merged_cache_size;
423 initialized_ = true;
424
425 // The actual IO is asynchronous, so calling WriteToDisk() shouldn't slow the
426 // merge down much.
427 if (load_result->flush_required)
428 WriteToDisk();
429
430 SIMPLE_CACHE_UMA(CUSTOM_COUNTS,
431 "IndexInitializationWaiters", cache_type_,
432 to_run_when_initialized_.size(), 0, 100, 20);
433 // Run all callbacks waiting for the index to come up.
434 for (CallbackList::iterator it = to_run_when_initialized_.begin(),
435 end = to_run_when_initialized_.end(); it != end; ++it) {
436 io_thread_->PostTask(FROM_HERE, base::Bind((*it), net::OK));
437 }
438 to_run_when_initialized_.clear();
439 }
440
441 #if defined(OS_ANDROID)
OnApplicationStateChange(base::android::ApplicationState state)442 void SimpleIndex::OnApplicationStateChange(
443 base::android::ApplicationState state) {
444 DCHECK(io_thread_checker_.CalledOnValidThread());
445 // For more info about android activities, see:
446 // developer.android.com/training/basics/activity-lifecycle/pausing.html
447 if (state == base::android::APPLICATION_STATE_HAS_RUNNING_ACTIVITIES) {
448 app_on_background_ = false;
449 } else if (state ==
450 base::android::APPLICATION_STATE_HAS_STOPPED_ACTIVITIES) {
451 app_on_background_ = true;
452 WriteToDisk();
453 }
454 }
455 #endif
456
WriteToDisk()457 void SimpleIndex::WriteToDisk() {
458 DCHECK(io_thread_checker_.CalledOnValidThread());
459 if (!initialized_)
460 return;
461 SIMPLE_CACHE_UMA(CUSTOM_COUNTS,
462 "IndexNumEntriesOnWrite", cache_type_,
463 entries_set_.size(), 0, 100000, 50);
464 const base::TimeTicks start = base::TimeTicks::Now();
465 if (!last_write_to_disk_.is_null()) {
466 if (app_on_background_) {
467 SIMPLE_CACHE_UMA(MEDIUM_TIMES,
468 "IndexWriteInterval.Background", cache_type_,
469 start - last_write_to_disk_);
470 } else {
471 SIMPLE_CACHE_UMA(MEDIUM_TIMES,
472 "IndexWriteInterval.Foreground", cache_type_,
473 start - last_write_to_disk_);
474 }
475 }
476 last_write_to_disk_ = start;
477
478 index_file_->WriteToDisk(entries_set_, cache_size_,
479 start, app_on_background_);
480 }
481
482 } // namespace disk_cache
483