net/disk_cache/memory/mem_backend_impl.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 "net/disk_cache/memory/mem_backend_impl.h"
   6
   7 #include "base/logging.h"
   8 #include "base/sys_info.h"
   9 #include "net/base/net_errors.h"
  10 #include "net/disk_cache/cache_util.h"
  11 #include "net/disk_cache/memory/mem_entry_impl.h"
  12
  13 using base::Time;
  14
  15 namespace {
  16
  17 const int kDefaultInMemoryCacheSize = 10 * 1024 * 1024;
  18 const int kCleanUpMargin = 1024 * 1024;
  19
  20 int LowWaterAdjust(int high_water) {
  21   if (high_water < kCleanUpMargin)
  22     return 0;
  23
  24   return high_water - kCleanUpMargin;
  25 }
  26
  27 }  // namespace
  28
  29 namespace disk_cache {
  30
  31 MemBackendImpl::MemBackendImpl(net::NetLog* net_log)
  32     : max_size_(0), current_size_(0), net_log_(net_log), weak_factory_(this) {
  33 }
  34
  35 MemBackendImpl::~MemBackendImpl() {
  36   EntryMap::iterator it = entries_.begin();
  37   while (it != entries_.end()) {
  38     it->second->Doom();
  39     it = entries_.begin();
  40   }
  41   DCHECK(!current_size_);
  42 }
  43
  44 // Static.
  45 scoped_ptr<Backend> MemBackendImpl::CreateBackend(int max_bytes,
  46                                                   net::NetLog* net_log) {
  47   scoped_ptr<MemBackendImpl> cache(new MemBackendImpl(net_log));
  48   cache->SetMaxSize(max_bytes);
  49   if (cache->Init())
  50     return cache.Pass();
  51
  52   LOG(ERROR) << "Unable to create cache";
  53   return nullptr;
  54 }
  55
  56 bool MemBackendImpl::Init() {
  57   if (max_size_)
  58     return true;
  59
  60   int64 total_memory = base::SysInfo::AmountOfPhysicalMemory();
  61
  62   if (total_memory <= 0) {
  63     max_size_ = kDefaultInMemoryCacheSize;
  64     return true;
  65   }
  66
  67   // We want to use up to 2% of the computer's memory, with a limit of 50 MB,
  68   // reached on systemd with more than 2.5 GB of RAM.
  69   total_memory = total_memory * 2 / 100;
  70   if (total_memory > kDefaultInMemoryCacheSize * 5)
  71     max_size_ = kDefaultInMemoryCacheSize * 5;
  72   else
  73     max_size_ = static_cast<int32>(total_memory);
  74
  75   return true;
  76 }
  77
  78 bool MemBackendImpl::SetMaxSize(int max_bytes) {
  79   COMPILE_ASSERT(sizeof(max_bytes) == sizeof(max_size_), unsupported_int_model);
  80   if (max_bytes < 0)
  81     return false;
  82
  83   // Zero size means use the default.
  84   if (!max_bytes)
  85     return true;
  86
  87   max_size_ = max_bytes;
  88   return true;
  89 }
  90
  91 void MemBackendImpl::InternalDoomEntry(MemEntryImpl* entry) {
  92   // Only parent entries can be passed into this method.
  93   DCHECK(entry->type() == MemEntryImpl::kParentEntry);
  94
  95   rankings_.Remove(entry);
  96   EntryMap::iterator it = entries_.find(entry->GetKey());
  97   if (it != entries_.end())
  98     entries_.erase(it);
  99   else
 100     NOTREACHED();
 101
 102   entry->InternalDoom();
 103 }
 104
 105 void MemBackendImpl::UpdateRank(MemEntryImpl* node) {
 106   rankings_.UpdateRank(node);
 107 }
 108
 109 void MemBackendImpl::ModifyStorageSize(int32 old_size, int32 new_size) {
 110   if (old_size >= new_size)
 111     SubstractStorageSize(old_size - new_size);
 112   else
 113     AddStorageSize(new_size - old_size);
 114 }
 115
 116 int MemBackendImpl::MaxFileSize() const {
 117   return max_size_ / 8;
 118 }
 119
 120 void MemBackendImpl::InsertIntoRankingList(MemEntryImpl* entry) {
 121   rankings_.Insert(entry);
 122 }
 123
 124 void MemBackendImpl::RemoveFromRankingList(MemEntryImpl* entry) {
 125   rankings_.Remove(entry);
 126 }
 127
 128 net::CacheType MemBackendImpl::GetCacheType() const {
 129   return net::MEMORY_CACHE;
 130 }
 131
 132 int32 MemBackendImpl::GetEntryCount() const {
 133   return static_cast<int32>(entries_.size());
 134 }
 135
 136 int MemBackendImpl::OpenEntry(const std::string& key, Entry** entry,
 137                               const CompletionCallback& callback) {
 138   if (OpenEntry(key, entry))
 139     return net::OK;
 140
 141   return net::ERR_FAILED;
 142 }
 143
 144 int MemBackendImpl::CreateEntry(const std::string& key, Entry** entry,
 145                                 const CompletionCallback& callback) {
 146   if (CreateEntry(key, entry))
 147     return net::OK;
 148
 149   return net::ERR_FAILED;
 150 }
 151
 152 int MemBackendImpl::DoomEntry(const std::string& key,
 153                               const CompletionCallback& callback) {
 154   if (DoomEntry(key))
 155     return net::OK;
 156
 157   return net::ERR_FAILED;
 158 }
 159
 160 int MemBackendImpl::DoomAllEntries(const CompletionCallback& callback) {
 161   if (DoomAllEntries())
 162     return net::OK;
 163
 164   return net::ERR_FAILED;
 165 }
 166
 167 int MemBackendImpl::DoomEntriesBetween(const base::Time initial_time,
 168                                        const base::Time end_time,
 169                                        const CompletionCallback& callback) {
 170   if (DoomEntriesBetween(initial_time, end_time))
 171     return net::OK;
 172
 173   return net::ERR_FAILED;
 174 }
 175
 176 int MemBackendImpl::DoomEntriesSince(const base::Time initial_time,
 177                                      const CompletionCallback& callback) {
 178   if (DoomEntriesSince(initial_time))
 179     return net::OK;
 180
 181   return net::ERR_FAILED;
 182 }
 183
 184 class MemBackendImpl::MemIterator : public Backend::Iterator {
 185  public:
 186   explicit MemIterator(base::WeakPtr<MemBackendImpl> backend)
 187       : backend_(backend), current_(NULL) {
 188   }
 189
 190   int OpenNextEntry(Entry** next_entry,
 191                     const CompletionCallback& callback) override {
 192     if (!backend_)
 193       return net::ERR_FAILED;
 194
 195     MemEntryImpl* node = backend_->rankings_.GetNext(current_);
 196     // We should never return a child entry so iterate until we hit a parent
 197     // entry.
 198     while (node && node->type() != MemEntryImpl::kParentEntry)
 199       node = backend_->rankings_.GetNext(node);
 200     *next_entry = node;
 201     current_ = node;
 202
 203     if (node) {
 204       node->Open();
 205       return net::OK;
 206     }
 207     return net::ERR_FAILED;
 208   }
 209
 210  private:
 211   base::WeakPtr<MemBackendImpl> backend_;
 212   MemEntryImpl* current_;
 213 };
 214
 215 scoped_ptr<Backend::Iterator> MemBackendImpl::CreateIterator() {
 216   return scoped_ptr<Backend::Iterator>(
 217       new MemIterator(weak_factory_.GetWeakPtr()));
 218 }
 219
 220 void MemBackendImpl::OnExternalCacheHit(const std::string& key) {
 221   EntryMap::iterator it = entries_.find(key);
 222   if (it != entries_.end()) {
 223     UpdateRank(it->second);
 224   }
 225 }
 226
 227 bool MemBackendImpl::OpenEntry(const std::string& key, Entry** entry) {
 228   EntryMap::iterator it = entries_.find(key);
 229   if (it == entries_.end())
 230     return false;
 231
 232   it->second->Open();
 233
 234   *entry = it->second;
 235   return true;
 236 }
 237
 238 bool MemBackendImpl::CreateEntry(const std::string& key, Entry** entry) {
 239   EntryMap::iterator it = entries_.find(key);
 240   if (it != entries_.end())
 241     return false;
 242
 243   MemEntryImpl* cache_entry = new MemEntryImpl(this);
 244   if (!cache_entry->CreateEntry(key, net_log_)) {
 245     delete entry;
 246     return false;
 247   }
 248
 249   rankings_.Insert(cache_entry);
 250   entries_[key] = cache_entry;
 251
 252   *entry = cache_entry;
 253   return true;
 254 }
 255
 256 bool MemBackendImpl::DoomEntry(const std::string& key) {
 257   Entry* entry;
 258   if (!OpenEntry(key, &entry))
 259     return false;
 260
 261   entry->Doom();
 262   entry->Close();
 263   return true;
 264 }
 265
 266 bool MemBackendImpl::DoomAllEntries() {
 267   TrimCache(true);
 268   return true;
 269 }
 270
 271 bool MemBackendImpl::DoomEntriesBetween(const Time initial_time,
 272                                         const Time end_time) {
 273   if (end_time.is_null())
 274     return DoomEntriesSince(initial_time);
 275
 276   DCHECK(end_time >= initial_time);
 277
 278   MemEntryImpl* node = rankings_.GetNext(NULL);
 279   // Last valid entry before |node|.
 280   // Note, that entries after |node| may become invalid during |node| doom in
 281   // case when they are child entries of it. It is guaranteed that
 282   // parent node will go prior to it childs in ranking list (see
 283   // InternalReadSparseData and InternalWriteSparseData).
 284   MemEntryImpl* last_valid = NULL;
 285
 286   // rankings_ is ordered by last used, this will descend through the cache
 287   // and start dooming items before the end_time, and will stop once it reaches
 288   // an item used before the initial time.
 289   while (node) {
 290     if (node->GetLastUsed() < initial_time)
 291       break;
 292
 293     if (node->GetLastUsed() < end_time)
 294       node->Doom();
 295     else
 296       last_valid = node;
 297     node = rankings_.GetNext(last_valid);
 298   }
 299
 300   return true;
 301 }
 302
 303 bool MemBackendImpl::DoomEntriesSince(const Time initial_time) {
 304   for (;;) {
 305     // Get the entry in the front.
 306     Entry* entry = rankings_.GetNext(NULL);
 307
 308     // Break the loop when there are no more entries or the entry is too old.
 309     if (!entry || entry->GetLastUsed() < initial_time)
 310       return true;
 311     entry->Doom();
 312   }
 313 }
 314
 315 void MemBackendImpl::TrimCache(bool empty) {
 316   MemEntryImpl* next = rankings_.GetPrev(NULL);
 317   if (!next)
 318     return;
 319
 320   int target_size = empty ? 0 : LowWaterAdjust(max_size_);
 321   while (current_size_ > target_size && next) {
 322     MemEntryImpl* node = next;
 323     next = rankings_.GetPrev(next);
 324     if (!node->InUse() || empty) {
 325       node->Doom();
 326     }
 327   }
 328
 329   return;
 330 }
 331
 332 void MemBackendImpl::AddStorageSize(int32 bytes) {
 333   current_size_ += bytes;
 334   DCHECK_GE(current_size_, 0);
 335
 336   if (current_size_ > max_size_)
 337     TrimCache(false);
 338 }
 339
 340 void MemBackendImpl::SubstractStorageSize(int32 bytes) {
 341   current_size_ -= bytes;
 342   DCHECK_GE(current_size_, 0);
 343 }
 344
 345 }  // namespace disk_cache