net/disk_cache/simple/simple_index.h

   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 #ifndef NET_DISK_CACHE_SIMPLE_SIMPLE_INDEX_H_
   6 #define NET_DISK_CACHE_SIMPLE_SIMPLE_INDEX_H_
   7
   8 #include <list>
   9 #include <string>
  10 #include <vector>
  11
  12 #include "base/basictypes.h"
  13 #include "base/callback.h"
  14 #include "base/containers/hash_tables.h"
  15 #include "base/files/file_path.h"
  16 #include "base/gtest_prod_util.h"
  17 #include "base/memory/ref_counted.h"
  18 #include "base/memory/scoped_ptr.h"
  19 #include "base/memory/weak_ptr.h"
  20 #include "base/single_thread_task_runner.h"
  21 #include "base/threading/thread_checker.h"
  22 #include "base/time/time.h"
  23 #include "base/timer/timer.h"
  24 #include "net/base/completion_callback.h"
  25 #include "net/base/net_export.h"
  26
  27 #if defined(OS_ANDROID)
  28 #include "base/android/activity_status.h"
  29 #endif
  30
  31 class Pickle;
  32 class PickleIterator;
  33
  34 namespace disk_cache {
  35
  36 class SimpleIndexFile;
  37 struct SimpleIndexLoadResult;
  38
  39 class NET_EXPORT_PRIVATE EntryMetadata {
  40  public:
  41   EntryMetadata();
  42   EntryMetadata(base::Time last_used_time, uint64 entry_size);
  43
  44   base::Time GetLastUsedTime() const;
  45   void SetLastUsedTime(const base::Time& last_used_time);
  46
  47   uint64 GetEntrySize() const { return entry_size_; }
  48   void SetEntrySize(uint64 entry_size) { entry_size_ = entry_size; }
  49
  50   // Serialize the data into the provided pickle.
  51   void Serialize(Pickle* pickle) const;
  52   bool Deserialize(PickleIterator* it);
  53
  54  private:
  55   friend class SimpleIndexFileTest;
  56
  57   // When adding new members here, you should update the Serialize() and
  58   // Deserialize() methods.
  59
  60   // This is the serialized format from Time::ToInternalValue().
  61   // If you want to make calculations/comparisons, you should use the
  62   // base::Time() class. Use the GetLastUsedTime() method above.
  63   // TODO(felipeg): Use Time() here.
  64   int64 last_used_time_;
  65
  66   uint64 entry_size_;  // Storage size in bytes.
  67 };
  68
  69 // This class is not Thread-safe.
  70 class NET_EXPORT_PRIVATE SimpleIndex
  71     : public base::SupportsWeakPtr<SimpleIndex> {
  72  public:
  73   typedef std::vector<uint64> HashList;
  74
  75   SimpleIndex(base::SingleThreadTaskRunner* io_thread,
  76               const base::FilePath& cache_directory,
  77               scoped_ptr<SimpleIndexFile> simple_index_file);
  78
  79   virtual ~SimpleIndex();
  80
  81   void Initialize(base::Time cache_mtime);
  82
  83   bool SetMaxSize(int max_bytes);
  84   int max_size() const { return max_size_; }
  85
  86   void Insert(const std::string& key);
  87   void Remove(const std::string& key);
  88
  89   // Check whether the index has the entry given the hash of its key.
  90   bool Has(uint64 hash) const;
  91
  92   // Update the last used time of the entry with the given key and return true
  93   // iff the entry exist in the index.
  94   bool UseIfExists(const std::string& key);
  95
  96   void WriteToDisk();
  97
  98   // Update the size (in bytes) of an entry, in the metadata stored in the
  99   // index. This should be the total disk-file size including all streams of the
 100   // entry.
 101   bool UpdateEntrySize(const std::string& key, uint64 entry_size);
 102
 103   typedef base::hash_map<uint64, EntryMetadata> EntrySet;
 104
 105   static void InsertInEntrySet(uint64 hash_key,
 106                                const EntryMetadata& entry_metadata,
 107                                EntrySet* entry_set);
 108
 109   // Executes the |callback| when the index is ready. Allows multiple callbacks.
 110   int ExecuteWhenReady(const net::CompletionCallback& callback);
 111
 112   // Takes out entries from the index that have last accessed time matching the
 113   // range between |initial_time| and |end_time| where open intervals are
 114   // possible according to the definition given in |DoomEntriesBetween()| in the
 115   // disk cache backend interface. Returns the set of hashes taken out.
 116   scoped_ptr<HashList> RemoveEntriesBetween(const base::Time initial_time,
 117                                             const base::Time end_time);
 118
 119   // Returns the list of all entries key hash.
 120   scoped_ptr<HashList> GetAllHashes();
 121
 122   // Returns number of indexed entries.
 123   int32 GetEntryCount() const;
 124
 125   // Returns whether the index has been initialized yet.
 126   bool initialized() const { return initialized_; }
 127
 128  private:
 129   friend class SimpleIndexTest;
 130   FRIEND_TEST_ALL_PREFIXES(SimpleIndexTest, IndexSizeCorrectOnMerge);
 131   FRIEND_TEST_ALL_PREFIXES(SimpleIndexTest, DiskWriteQueued);
 132   FRIEND_TEST_ALL_PREFIXES(SimpleIndexTest, DiskWriteExecuted);
 133   FRIEND_TEST_ALL_PREFIXES(SimpleIndexTest, DiskWritePostponed);
 134
 135   void StartEvictionIfNeeded();
 136   void EvictionDone(int result);
 137
 138   void PostponeWritingToDisk();
 139
 140   void UpdateEntryIteratorSize(EntrySet::iterator* it, uint64 entry_size);
 141
 142   // Must run on IO Thread.
 143   void MergeInitializingSet(scoped_ptr<SimpleIndexLoadResult> load_result);
 144
 145 #if defined(OS_ANDROID)
 146   void OnActivityStateChange(base::android::ActivityState state);
 147
 148   scoped_ptr<base::android::ActivityStatus::Listener> activity_status_listener_;
 149 #endif
 150
 151   scoped_ptr<HashList> ExtractEntriesBetween(const base::Time initial_time,
 152                                              const base::Time end_time,
 153                                              bool delete_entries);
 154
 155   EntrySet entries_set_;
 156
 157   uint64 cache_size_;  // Total cache storage size in bytes.
 158   uint64 max_size_;
 159   uint64 high_watermark_;
 160   uint64 low_watermark_;
 161   bool eviction_in_progress_;
 162   base::TimeTicks eviction_start_time_;
 163
 164   // This stores all the hash_key of entries that are removed during
 165   // initialization.
 166   base::hash_set<uint64> removed_entries_;
 167   bool initialized_;
 168
 169   const base::FilePath& cache_directory_;
 170   scoped_ptr<SimpleIndexFile> index_file_;
 171
 172   scoped_refptr<base::SingleThreadTaskRunner> io_thread_;
 173
 174   // All nonstatic SimpleEntryImpl methods should always be called on the IO
 175   // thread, in all cases. |io_thread_checker_| documents and enforces this.
 176   base::ThreadChecker io_thread_checker_;
 177
 178   // Timestamp of the last time we wrote the index to disk.
 179   // PostponeWritingToDisk() may give up postponing and allow the write if it
 180   // has been a while since last time we wrote.
 181   base::TimeTicks last_write_to_disk_;
 182
 183   base::OneShotTimer<SimpleIndex> write_to_disk_timer_;
 184   base::Closure write_to_disk_cb_;
 185
 186   typedef std::list<net::CompletionCallback> CallbackList;
 187   CallbackList to_run_when_initialized_;
 188
 189   // Set to true when the app is on the background. When the app is in the
 190   // background we can write the index much more frequently, to insure fresh
 191   // index on next startup.
 192   bool app_on_background_;
 193
 194   // The time in milliseconds for the index to be idle before it gets flushed to
 195   // the disk. When the app is on foreground the delay is different from the
 196   // background state.
 197   int foreground_flush_delay_;
 198   int background_flush_delay_;
 199 };
 200
 201 }  // namespace disk_cache
 202
 203 #endif  // NET_DISK_CACHE_SIMPLE_SIMPLE_INDEX_H_