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1 // Copyright 2013 The Chromium Authors
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/check_op.h"
13 #include "base/files/file_util.h"
14 #include "base/functional/bind.h"
15 #include "base/numerics/safe_conversions.h"
16 #include "base/pickle.h"
17 #include "base/strings/string_number_conversions.h"
18 #include "base/strings/string_tokenizer.h"
19 #include "base/task/sequenced_task_runner.h"
20 #include "base/task/task_runner.h"
21 #include "base/time/time.h"
22 #include "base/trace_event/memory_usage_estimator.h"
23 #include "build/build_config.h"
24 #include "net/base/net_errors.h"
25 #include "net/disk_cache/backend_cleanup_tracker.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 BUILDFLAG(IS_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_t kEvictionMarginDivisor = 20;
48 
49 const uint32_t kBytesInKb = 1024;
50 
51 // This is added to the size of each entry before using the size
52 // to determine which entries to evict first. It's basically an
53 // estimate of the filesystem overhead, but it also serves to flatten
54 // the curve so that 1-byte entries and 2-byte entries are basically
55 // treated the same.
56 static const int kEstimatedEntryOverhead = 512;
57 
58 }  // namespace
59 
60 namespace disk_cache {
61 
EntryMetadata()62 EntryMetadata::EntryMetadata()
63     : last_used_time_seconds_since_epoch_(0),
64       entry_size_256b_chunks_(0),
65       in_memory_data_(0) {}
66 
EntryMetadata(base::Time last_used_time,base::StrictNumeric<uint32_t> entry_size)67 EntryMetadata::EntryMetadata(base::Time last_used_time,
68                              base::StrictNumeric<uint32_t> entry_size)
69     : last_used_time_seconds_since_epoch_(0),
70       entry_size_256b_chunks_(0),
71       in_memory_data_(0) {
72   SetEntrySize(entry_size);  // to round/pack properly.
73   SetLastUsedTime(last_used_time);
74 }
75 
EntryMetadata(int32_t trailer_prefetch_size,base::StrictNumeric<uint32_t> entry_size)76 EntryMetadata::EntryMetadata(int32_t trailer_prefetch_size,
77                              base::StrictNumeric<uint32_t> entry_size)
78     : trailer_prefetch_size_(0),
79       entry_size_256b_chunks_(0),
80       in_memory_data_(0) {
81   SetEntrySize(entry_size);  // to round/pack properly
82   SetTrailerPrefetchSize(trailer_prefetch_size);
83 }
84 
GetLastUsedTime() const85 base::Time EntryMetadata::GetLastUsedTime() const {
86   // Preserve nullity.
87   if (last_used_time_seconds_since_epoch_ == 0)
88     return base::Time();
89 
90   return base::Time::UnixEpoch() +
91          base::Seconds(last_used_time_seconds_since_epoch_);
92 }
93 
SetLastUsedTime(const base::Time & last_used_time)94 void EntryMetadata::SetLastUsedTime(const base::Time& last_used_time) {
95   // Preserve nullity.
96   if (last_used_time.is_null()) {
97     last_used_time_seconds_since_epoch_ = 0;
98     return;
99   }
100 
101   last_used_time_seconds_since_epoch_ = base::saturated_cast<uint32_t>(
102       (last_used_time - base::Time::UnixEpoch()).InSeconds());
103   // Avoid accidental nullity.
104   if (last_used_time_seconds_since_epoch_ == 0)
105     last_used_time_seconds_since_epoch_ = 1;
106 }
107 
GetTrailerPrefetchSize() const108 int32_t EntryMetadata::GetTrailerPrefetchSize() const {
109   return trailer_prefetch_size_;
110 }
111 
SetTrailerPrefetchSize(int32_t size)112 void EntryMetadata::SetTrailerPrefetchSize(int32_t size) {
113   if (size <= 0)
114     return;
115   trailer_prefetch_size_ = size;
116 }
117 
GetEntrySize() const118 uint32_t EntryMetadata::GetEntrySize() const {
119   return entry_size_256b_chunks_ << 8;
120 }
121 
SetEntrySize(base::StrictNumeric<uint32_t> entry_size)122 void EntryMetadata::SetEntrySize(base::StrictNumeric<uint32_t> entry_size) {
123   // This should not overflow since we limit entries to 1/8th of the cache.
124   entry_size_256b_chunks_ = (static_cast<uint32_t>(entry_size) + 255) >> 8;
125 }
126 
Serialize(net::CacheType cache_type,base::Pickle * pickle) const127 void EntryMetadata::Serialize(net::CacheType cache_type,
128                               base::Pickle* pickle) const {
129   DCHECK(pickle);
130   // If you modify the size of the size of the pickle, be sure to update
131   // kOnDiskSizeBytes.
132   uint32_t packed_entry_info = (entry_size_256b_chunks_ << 8) | in_memory_data_;
133   if (cache_type == net::APP_CACHE) {
134     pickle->WriteInt64(trailer_prefetch_size_);
135   } else {
136     int64_t internal_last_used_time = GetLastUsedTime().ToInternalValue();
137     pickle->WriteInt64(internal_last_used_time);
138   }
139   pickle->WriteUInt64(packed_entry_info);
140 }
141 
Deserialize(net::CacheType cache_type,base::PickleIterator * it,bool has_entry_in_memory_data,bool app_cache_has_trailer_prefetch_size)142 bool EntryMetadata::Deserialize(net::CacheType cache_type,
143                                 base::PickleIterator* it,
144                                 bool has_entry_in_memory_data,
145                                 bool app_cache_has_trailer_prefetch_size) {
146   DCHECK(it);
147   int64_t tmp_time_or_prefetch_size;
148   uint64_t tmp_entry_size;
149   if (!it->ReadInt64(&tmp_time_or_prefetch_size) ||
150       !it->ReadUInt64(&tmp_entry_size) ||
151       tmp_entry_size > std::numeric_limits<uint32_t>::max())
152     return false;
153   if (cache_type == net::APP_CACHE) {
154     if (app_cache_has_trailer_prefetch_size) {
155       int32_t trailer_prefetch_size = 0;
156       base::CheckedNumeric<int32_t> numeric_size(tmp_time_or_prefetch_size);
157       if (numeric_size.AssignIfValid(&trailer_prefetch_size)) {
158         SetTrailerPrefetchSize(trailer_prefetch_size);
159       }
160     }
161   } else {
162     SetLastUsedTime(base::Time::FromInternalValue(tmp_time_or_prefetch_size));
163   }
164   if (has_entry_in_memory_data) {
165     // tmp_entry_size actually packs entry_size_256b_chunks_ and
166     // in_memory_data_.
167     SetEntrySize(static_cast<uint32_t>(tmp_entry_size & 0xFFFFFF00));
168     SetInMemoryData(static_cast<uint8_t>(tmp_entry_size & 0xFF));
169   } else {
170     SetEntrySize(static_cast<uint32_t>(tmp_entry_size));
171     SetInMemoryData(0);
172   }
173   return true;
174 }
175 
SimpleIndex(const scoped_refptr<base::SequencedTaskRunner> & task_runner,scoped_refptr<BackendCleanupTracker> cleanup_tracker,SimpleIndexDelegate * delegate,net::CacheType cache_type,std::unique_ptr<SimpleIndexFile> index_file)176 SimpleIndex::SimpleIndex(
177     const scoped_refptr<base::SequencedTaskRunner>& task_runner,
178     scoped_refptr<BackendCleanupTracker> cleanup_tracker,
179     SimpleIndexDelegate* delegate,
180     net::CacheType cache_type,
181     std::unique_ptr<SimpleIndexFile> index_file)
182     : cleanup_tracker_(std::move(cleanup_tracker)),
183       delegate_(delegate),
184       cache_type_(cache_type),
185       index_file_(std::move(index_file)),
186       task_runner_(task_runner),
187       // Creating the callback once so it is reused every time
188       // write_to_disk_timer_.Start() is called.
189       write_to_disk_cb_(base::BindRepeating(&SimpleIndex::WriteToDisk,
190                                             AsWeakPtr(),
191                                             INDEX_WRITE_REASON_IDLE)) {}
192 
~SimpleIndex()193 SimpleIndex::~SimpleIndex() {
194   DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
195 
196   // Fail all callbacks waiting for the index to come up.
197   for (auto& callback : to_run_when_initialized_) {
198     std::move(callback).Run(net::ERR_ABORTED);
199   }
200 }
201 
Initialize(base::Time cache_mtime)202 void SimpleIndex::Initialize(base::Time cache_mtime) {
203   DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
204 
205 #if BUILDFLAG(IS_ANDROID)
206   if (app_status_listener_) {
207     app_status_listener_->SetCallback(base::BindRepeating(
208         &SimpleIndex::OnApplicationStateChange, AsWeakPtr()));
209   } else if (base::android::IsVMInitialized()) {
210     owned_app_status_listener_ =
211         base::android::ApplicationStatusListener::New(base::BindRepeating(
212             &SimpleIndex::OnApplicationStateChange, AsWeakPtr()));
213     app_status_listener_ = owned_app_status_listener_.get();
214   }
215 #endif
216 
217   auto load_result = std::make_unique<SimpleIndexLoadResult>();
218   auto* load_result_ptr = load_result.get();
219   index_file_->LoadIndexEntries(
220       cache_mtime,
221       base::BindOnce(&SimpleIndex::MergeInitializingSet, AsWeakPtr(),
222                      std::move(load_result)),
223       load_result_ptr);
224 }
225 
SetMaxSize(uint64_t max_bytes)226 void SimpleIndex::SetMaxSize(uint64_t max_bytes) {
227   // Zero size means use the default.
228   if (max_bytes) {
229     max_size_ = max_bytes;
230     high_watermark_ = max_size_ - max_size_ / kEvictionMarginDivisor;
231     low_watermark_ = max_size_ - 2 * (max_size_ / kEvictionMarginDivisor);
232   }
233 }
234 
ExecuteWhenReady(net::CompletionOnceCallback task)235 void SimpleIndex::ExecuteWhenReady(net::CompletionOnceCallback task) {
236   DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
237   if (initialized_)
238     task_runner_->PostTask(FROM_HERE, base::BindOnce(std::move(task), net::OK));
239   else
240     to_run_when_initialized_.push_back(std::move(task));
241 }
242 
GetEntriesBetween(base::Time initial_time,base::Time end_time)243 std::unique_ptr<SimpleIndex::HashList> SimpleIndex::GetEntriesBetween(
244     base::Time initial_time,
245     base::Time end_time) {
246   DCHECK_EQ(true, initialized_);
247 
248   // The net::APP_CACHE mode does not track access times.  Assert that external
249   // consumers are not relying on access time ranges.
250   DCHECK(cache_type_ != net::APP_CACHE ||
251          (initial_time.is_null() && end_time.is_null()));
252 
253   if (!initial_time.is_null())
254     initial_time -= EntryMetadata::GetLowerEpsilonForTimeComparisons();
255   if (end_time.is_null())
256     end_time = base::Time::Max();
257   else
258     end_time += EntryMetadata::GetUpperEpsilonForTimeComparisons();
259   DCHECK(end_time >= initial_time);
260 
261   auto ret_hashes = std::make_unique<HashList>();
262   for (const auto& entry : entries_set_) {
263     const EntryMetadata& metadata = entry.second;
264     base::Time entry_time = metadata.GetLastUsedTime();
265     if (initial_time <= entry_time && entry_time < end_time)
266       ret_hashes->push_back(entry.first);
267   }
268   return ret_hashes;
269 }
270 
GetAllHashes()271 std::unique_ptr<SimpleIndex::HashList> SimpleIndex::GetAllHashes() {
272   return GetEntriesBetween(base::Time(), base::Time());
273 }
274 
GetEntryCount() const275 int32_t SimpleIndex::GetEntryCount() const {
276   // TODO(pasko): return a meaningful initial estimate before initialized.
277   return entries_set_.size();
278 }
279 
GetCacheSize() const280 uint64_t SimpleIndex::GetCacheSize() const {
281   DCHECK(initialized_);
282   return cache_size_;
283 }
284 
GetCacheSizeBetween(base::Time initial_time,base::Time end_time) const285 uint64_t SimpleIndex::GetCacheSizeBetween(base::Time initial_time,
286                                           base::Time end_time) const {
287   DCHECK_EQ(true, initialized_);
288 
289   if (!initial_time.is_null())
290     initial_time -= EntryMetadata::GetLowerEpsilonForTimeComparisons();
291   if (end_time.is_null())
292     end_time = base::Time::Max();
293   else
294     end_time += EntryMetadata::GetUpperEpsilonForTimeComparisons();
295 
296   DCHECK(end_time >= initial_time);
297   uint64_t size = 0;
298   for (const auto& entry : entries_set_) {
299     const EntryMetadata& metadata = entry.second;
300     base::Time entry_time = metadata.GetLastUsedTime();
301     if (initial_time <= entry_time && entry_time < end_time)
302       size += metadata.GetEntrySize();
303   }
304   return size;
305 }
306 
GetLastUsedTime(uint64_t entry_hash)307 base::Time SimpleIndex::GetLastUsedTime(uint64_t entry_hash) {
308   DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
309   DCHECK_NE(cache_type_, net::APP_CACHE);
310   auto it = entries_set_.find(entry_hash);
311   if (it == entries_set_.end())
312     return base::Time();
313   return it->second.GetLastUsedTime();
314 }
315 
SetLastUsedTimeForTest(uint64_t entry_hash,const base::Time last_used)316 void SimpleIndex::SetLastUsedTimeForTest(uint64_t entry_hash,
317                                          const base::Time last_used) {
318   auto it = entries_set_.find(entry_hash);
319   DCHECK(it != entries_set_.end());
320   it->second.SetLastUsedTime(last_used);
321 }
322 
HasPendingWrite() const323 bool SimpleIndex::HasPendingWrite() const {
324   return write_to_disk_timer_.IsRunning();
325 }
326 
Insert(uint64_t entry_hash)327 void SimpleIndex::Insert(uint64_t entry_hash) {
328   DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
329   // Upon insert we don't know yet the size of the entry.
330   // It will be updated later when the SimpleEntryImpl finishes opening or
331   // creating the new entry, and then UpdateEntrySize will be called.
332   bool inserted = false;
333   if (cache_type_ == net::APP_CACHE) {
334     inserted =
335         InsertInEntrySet(entry_hash, EntryMetadata(-1, 0u), &entries_set_);
336   } else {
337     inserted = InsertInEntrySet(
338         entry_hash, EntryMetadata(base::Time::Now(), 0u), &entries_set_);
339   }
340   if (!initialized_)
341     removed_entries_.erase(entry_hash);
342   if (inserted)
343     PostponeWritingToDisk();
344 }
345 
Remove(uint64_t entry_hash)346 void SimpleIndex::Remove(uint64_t entry_hash) {
347   DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
348   bool need_write = false;
349   auto it = entries_set_.find(entry_hash);
350   if (it != entries_set_.end()) {
351     UpdateEntryIteratorSize(&it, 0u);
352     entries_set_.erase(it);
353     need_write = true;
354   }
355 
356   if (!initialized_)
357     removed_entries_.insert(entry_hash);
358 
359   if (need_write)
360     PostponeWritingToDisk();
361 }
362 
Has(uint64_t hash) const363 bool SimpleIndex::Has(uint64_t hash) const {
364   DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
365   // If not initialized, always return true, forcing it to go to the disk.
366   return !initialized_ || entries_set_.count(hash) > 0;
367 }
368 
GetEntryInMemoryData(uint64_t entry_hash) const369 uint8_t SimpleIndex::GetEntryInMemoryData(uint64_t entry_hash) const {
370   DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
371   auto it = entries_set_.find(entry_hash);
372   if (it == entries_set_.end())
373     return 0;
374   return it->second.GetInMemoryData();
375 }
376 
SetEntryInMemoryData(uint64_t entry_hash,uint8_t value)377 void SimpleIndex::SetEntryInMemoryData(uint64_t entry_hash, uint8_t value) {
378   DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
379   auto it = entries_set_.find(entry_hash);
380   if (it == entries_set_.end())
381     return;
382   return it->second.SetInMemoryData(value);
383 }
384 
UseIfExists(uint64_t entry_hash)385 bool SimpleIndex::UseIfExists(uint64_t entry_hash) {
386   DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
387   // Always update the last used time, even if it is during initialization.
388   // It will be merged later.
389   auto it = entries_set_.find(entry_hash);
390   if (it == entries_set_.end())
391     // If not initialized, always return true, forcing it to go to the disk.
392     return !initialized_;
393   // We do not need to track access times in APP_CACHE mode.
394   if (cache_type_ == net::APP_CACHE)
395     return true;
396   it->second.SetLastUsedTime(base::Time::Now());
397   PostponeWritingToDisk();
398   return true;
399 }
400 
StartEvictionIfNeeded()401 void SimpleIndex::StartEvictionIfNeeded() {
402   DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
403   if (eviction_in_progress_ || cache_size_ <= high_watermark_)
404     return;
405   // Take all live key hashes from the index and sort them by time.
406   eviction_in_progress_ = true;
407   eviction_start_time_ = base::TimeTicks::Now();
408 
409   bool use_size_heuristic =
410       (cache_type_ != net::GENERATED_BYTE_CODE_CACHE &&
411        cache_type_ != net::GENERATED_WEBUI_BYTE_CODE_CACHE);
412 
413   // Flatten for sorting.
414   std::vector<std::pair<uint64_t, const EntrySet::value_type*>> entries;
415   entries.reserve(entries_set_.size());
416   uint32_t now = (base::Time::Now() - base::Time::UnixEpoch()).InSeconds();
417   for (EntrySet::const_iterator i = entries_set_.begin();
418        i != entries_set_.end(); ++i) {
419     uint64_t sort_value = now - i->second.RawTimeForSorting();
420     // See crbug.com/736437 for context.
421     //
422     // Will not overflow since we're multiplying two 32-bit values and storing
423     // them in a 64-bit variable.
424     if (use_size_heuristic)
425       sort_value *= i->second.GetEntrySize() + kEstimatedEntryOverhead;
426     // Subtract so we don't need a custom comparator.
427     entries.emplace_back(std::numeric_limits<uint64_t>::max() - sort_value,
428                          &*i);
429   }
430 
431   uint64_t evicted_so_far_size = 0;
432   const uint64_t amount_to_evict = cache_size_ - low_watermark_;
433   std::vector<uint64_t> entry_hashes;
434   std::sort(entries.begin(), entries.end());
435   for (const auto& score_metadata_pair : entries) {
436     if (evicted_so_far_size >= amount_to_evict)
437       break;
438     evicted_so_far_size += score_metadata_pair.second->second.GetEntrySize();
439     entry_hashes.push_back(score_metadata_pair.second->first);
440   }
441 
442   SIMPLE_CACHE_UMA(COUNTS_1M,
443                    "Eviction.EntryCount", cache_type_, entry_hashes.size());
444   SIMPLE_CACHE_UMA(TIMES,
445                    "Eviction.TimeToSelectEntries", cache_type_,
446                    base::TimeTicks::Now() - eviction_start_time_);
447 
448   delegate_->DoomEntries(
449       &entry_hashes, base::BindOnce(&SimpleIndex::EvictionDone, AsWeakPtr()));
450 }
451 
GetTrailerPrefetchSize(uint64_t entry_hash) const452 int32_t SimpleIndex::GetTrailerPrefetchSize(uint64_t entry_hash) const {
453   DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
454   DCHECK_EQ(cache_type_, net::APP_CACHE);
455   auto it = entries_set_.find(entry_hash);
456   if (it == entries_set_.end())
457     return -1;
458   return it->second.GetTrailerPrefetchSize();
459 }
460 
SetTrailerPrefetchSize(uint64_t entry_hash,int32_t size)461 void SimpleIndex::SetTrailerPrefetchSize(uint64_t entry_hash, int32_t size) {
462   DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
463   DCHECK_EQ(cache_type_, net::APP_CACHE);
464   auto it = entries_set_.find(entry_hash);
465   if (it == entries_set_.end())
466     return;
467   int32_t original_size = it->second.GetTrailerPrefetchSize();
468   it->second.SetTrailerPrefetchSize(size);
469   if (original_size != it->second.GetTrailerPrefetchSize())
470     PostponeWritingToDisk();
471 }
472 
UpdateEntrySize(uint64_t entry_hash,base::StrictNumeric<uint32_t> entry_size)473 bool SimpleIndex::UpdateEntrySize(uint64_t entry_hash,
474                                   base::StrictNumeric<uint32_t> entry_size) {
475   DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
476   auto it = entries_set_.find(entry_hash);
477   if (it == entries_set_.end())
478     return false;
479 
480   // Update the entry size.  If there was no change, then there is nothing
481   // else to do here.
482   if (!UpdateEntryIteratorSize(&it, entry_size))
483     return true;
484 
485   PostponeWritingToDisk();
486   StartEvictionIfNeeded();
487   return true;
488 }
489 
EvictionDone(int result)490 void SimpleIndex::EvictionDone(int result) {
491   DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
492 
493   // Ignore the result of eviction. We did our best.
494   eviction_in_progress_ = false;
495   SIMPLE_CACHE_UMA(TIMES,
496                    "Eviction.TimeToDone", cache_type_,
497                    base::TimeTicks::Now() - eviction_start_time_);
498 }
499 
500 // static
InsertInEntrySet(uint64_t entry_hash,const disk_cache::EntryMetadata & entry_metadata,EntrySet * entry_set)501 bool SimpleIndex::InsertInEntrySet(
502     uint64_t entry_hash,
503     const disk_cache::EntryMetadata& entry_metadata,
504     EntrySet* entry_set) {
505   DCHECK(entry_set);
506   auto result = entry_set->insert(std::make_pair(entry_hash, entry_metadata));
507   return result.second;
508 }
509 
InsertEntryForTesting(uint64_t entry_hash,const EntryMetadata & entry_metadata)510 void SimpleIndex::InsertEntryForTesting(uint64_t entry_hash,
511                                         const EntryMetadata& entry_metadata) {
512   DCHECK(entries_set_.find(entry_hash) == entries_set_.end());
513   if (InsertInEntrySet(entry_hash, entry_metadata, &entries_set_))
514     cache_size_ += entry_metadata.GetEntrySize();
515 }
516 
PostponeWritingToDisk()517 void SimpleIndex::PostponeWritingToDisk() {
518   if (!initialized_)
519     return;
520   const int delay = app_on_background_ ? kWriteToDiskOnBackgroundDelayMSecs
521                                        : kWriteToDiskDelayMSecs;
522   // If the timer is already active, Start() will just Reset it, postponing it.
523   write_to_disk_timer_.Start(FROM_HERE, base::Milliseconds(delay),
524                              write_to_disk_cb_);
525 }
526 
UpdateEntryIteratorSize(EntrySet::iterator * it,base::StrictNumeric<uint32_t> entry_size)527 bool SimpleIndex::UpdateEntryIteratorSize(
528     EntrySet::iterator* it,
529     base::StrictNumeric<uint32_t> entry_size) {
530   // Update the total cache size with the new entry size.
531   DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
532   DCHECK_GE(cache_size_, (*it)->second.GetEntrySize());
533   uint32_t original_size = (*it)->second.GetEntrySize();
534   cache_size_ -= (*it)->second.GetEntrySize();
535   (*it)->second.SetEntrySize(entry_size);
536   // We use GetEntrySize to get consistent rounding.
537   cache_size_ += (*it)->second.GetEntrySize();
538   // Return true if the size of the entry actually changed.  Make sure to
539   // compare the rounded values provided by GetEntrySize().
540   return original_size != (*it)->second.GetEntrySize();
541 }
542 
MergeInitializingSet(std::unique_ptr<SimpleIndexLoadResult> load_result)543 void SimpleIndex::MergeInitializingSet(
544     std::unique_ptr<SimpleIndexLoadResult> load_result) {
545   DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
546 
547   EntrySet* index_file_entries = &load_result->entries;
548 
549   for (uint64_t removed_entry : removed_entries_) {
550     index_file_entries->erase(removed_entry);
551   }
552   removed_entries_.clear();
553 
554   for (const auto& it : entries_set_) {
555     const uint64_t entry_hash = it.first;
556     std::pair<EntrySet::iterator, bool> insert_result =
557         index_file_entries->insert(EntrySet::value_type(entry_hash,
558                                                         EntryMetadata()));
559     EntrySet::iterator& possibly_inserted_entry = insert_result.first;
560     possibly_inserted_entry->second = it.second;
561   }
562 
563   uint64_t merged_cache_size = 0;
564   for (const auto& index_file_entry : *index_file_entries) {
565     merged_cache_size += index_file_entry.second.GetEntrySize();
566   }
567 
568   entries_set_.swap(*index_file_entries);
569   cache_size_ = merged_cache_size;
570   initialized_ = true;
571   init_method_ = load_result->init_method;
572 
573   // The actual IO is asynchronous, so calling WriteToDisk() shouldn't slow the
574   // merge down much.
575   if (load_result->flush_required)
576     WriteToDisk(INDEX_WRITE_REASON_STARTUP_MERGE);
577 
578   SIMPLE_CACHE_UMA(CUSTOM_COUNTS, "IndexNumEntriesOnInit", cache_type_,
579                    entries_set_.size(), 0, 100000, 50);
580   SIMPLE_CACHE_UMA(
581       MEMORY_KB, "CacheSizeOnInit", cache_type_,
582       static_cast<base::HistogramBase::Sample>(cache_size_ / kBytesInKb));
583   SIMPLE_CACHE_UMA(
584       MEMORY_KB, "MaxCacheSizeOnInit", cache_type_,
585       static_cast<base::HistogramBase::Sample>(max_size_ / kBytesInKb));
586 
587   // Run all callbacks waiting for the index to come up.
588   for (auto& callback : to_run_when_initialized_) {
589     task_runner_->PostTask(FROM_HERE,
590                            base::BindOnce(std::move(callback), net::OK));
591   }
592   to_run_when_initialized_.clear();
593 }
594 
595 #if BUILDFLAG(IS_ANDROID)
OnApplicationStateChange(base::android::ApplicationState state)596 void SimpleIndex::OnApplicationStateChange(
597     base::android::ApplicationState state) {
598   DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
599   // For more info about android activities, see:
600   // developer.android.com/training/basics/activity-lifecycle/pausing.html
601   if (state == base::android::APPLICATION_STATE_HAS_RUNNING_ACTIVITIES) {
602     app_on_background_ = false;
603   } else if (state ==
604       base::android::APPLICATION_STATE_HAS_STOPPED_ACTIVITIES) {
605     app_on_background_ = true;
606     WriteToDisk(INDEX_WRITE_REASON_ANDROID_STOPPED);
607   }
608 }
609 #endif
610 
WriteToDisk(IndexWriteToDiskReason reason)611 void SimpleIndex::WriteToDisk(IndexWriteToDiskReason reason) {
612   DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
613   if (!initialized_)
614     return;
615 
616   // Cancel any pending writes since we are about to write to disk now.
617   write_to_disk_timer_.AbandonAndStop();
618 
619   base::OnceClosure after_write;
620   if (cleanup_tracker_) {
621     // Make anyone synchronizing with our cleanup wait for the index to be
622     // written back.
623     after_write = base::DoNothingWithBoundArgs(cleanup_tracker_);
624   }
625 
626   index_file_->WriteToDisk(cache_type_, reason, entries_set_, cache_size_,
627                            std::move(after_write));
628 }
629 
630 }  // namespace disk_cache
631