webkit/dom_storage/dom_storage_area.h

   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 #ifndef WEBKIT_DOM_STORAGE_DOM_STORAGE_AREA_H_
   6 #define WEBKIT_DOM_STORAGE_DOM_STORAGE_AREA_H_
   7
   8 #include "base/files/file_path.h"
   9 #include "base/gtest_prod_util.h"
  10 #include "base/memory/ref_counted.h"
  11 #include "base/memory/scoped_ptr.h"
  12 #include "base/nullable_string16.h"
  13 #include "base/string16.h"
  14 #include "googleurl/src/gurl.h"
  15 #include "webkit/dom_storage/dom_storage_types.h"
  16 #include "webkit/storage/webkit_storage_export.h"
  17
  18 namespace dom_storage {
  19
  20 class DomStorageDatabaseAdapter;
  21 class DomStorageMap;
  22 class DomStorageTaskRunner;
  23 class SessionStorageDatabase;
  24
  25 // Container for a per-origin Map of key/value pairs potentially
  26 // backed by storage on disk and lazily commits changes to disk.
  27 // See class comments for DomStorageContext for a larger overview.
  28 class WEBKIT_STORAGE_EXPORT DomStorageArea
  29     : public base::RefCountedThreadSafe<DomStorageArea> {
  30
  31  public:
  32   static const base::FilePath::CharType kDatabaseFileExtension[];
  33   static base::FilePath DatabaseFileNameFromOrigin(const GURL& origin);
  34   static GURL OriginFromDatabaseFileName(const base::FilePath& file_name);
  35
  36   // Local storage. Backed on disk if directory is nonempty.
  37   DomStorageArea(const GURL& origin,
  38                  const base::FilePath& directory,
  39                  DomStorageTaskRunner* task_runner);
  40
  41   // Session storage. Backed on disk if |session_storage_backing| is not NULL.
  42   DomStorageArea(int64 namespace_id,
  43                  const std::string& persistent_namespace_id,
  44                  const GURL& origin,
  45                  SessionStorageDatabase* session_storage_backing,
  46                  DomStorageTaskRunner* task_runner);
  47
  48   const GURL& origin() const { return origin_; }
  49   int64 namespace_id() const { return namespace_id_; }
  50
  51   // Writes a copy of the current set of values in the area to the |map|.
  52   void ExtractValues(ValuesMap* map);
  53
  54   unsigned Length();
  55   NullableString16 Key(unsigned index);
  56   NullableString16 GetItem(const base::string16& key);
  57   bool SetItem(const base::string16& key, const base::string16& value,
  58                NullableString16* old_value);
  59   bool RemoveItem(const base::string16& key, base::string16* old_value);
  60   bool Clear();
  61   void FastClear();
  62
  63   DomStorageArea* ShallowCopy(
  64       int64 destination_namespace_id,
  65       const std::string& destination_persistent_namespace_id);
  66
  67   bool HasUncommittedChanges() const;
  68
  69   // Similar to Clear() but more optimized for just deleting
  70   // without raising events.
  71   void DeleteOrigin();
  72
  73   // Frees up memory when possible. Typically, this method returns
  74   // the object to its just constructed state, however if uncommitted
  75   // changes are pending, it does nothing.
  76   void PurgeMemory();
  77
  78   // Schedules the commit of any unsaved changes and enters a
  79   // shutdown state such that the value getters and setters will
  80   // no longer do anything.
  81   void Shutdown();
  82
  83   // Returns true if the data is loaded in memory.
  84   bool IsLoadedInMemory() const { return is_initial_import_done_; }
  85
  86  private:
  87   friend class DomStorageAreaTest;
  88   FRIEND_TEST_ALL_PREFIXES(DomStorageAreaTest, DomStorageAreaBasics);
  89   FRIEND_TEST_ALL_PREFIXES(DomStorageAreaTest, BackingDatabaseOpened);
  90   FRIEND_TEST_ALL_PREFIXES(DomStorageAreaTest, TestDatabaseFilePath);
  91   FRIEND_TEST_ALL_PREFIXES(DomStorageAreaTest, CommitTasks);
  92   FRIEND_TEST_ALL_PREFIXES(DomStorageAreaTest, CommitChangesAtShutdown);
  93   FRIEND_TEST_ALL_PREFIXES(DomStorageAreaTest, DeleteOrigin);
  94   FRIEND_TEST_ALL_PREFIXES(DomStorageAreaTest, PurgeMemory);
  95   FRIEND_TEST_ALL_PREFIXES(DomStorageContextTest, PersistentIds);
  96   friend class base::RefCountedThreadSafe<DomStorageArea>;
  97
  98   struct CommitBatch {
  99     bool clear_all_first;
 100     ValuesMap changed_values;
 101     CommitBatch();
 102     ~CommitBatch();
 103   };
 104
 105   ~DomStorageArea();
 106
 107   // If we haven't done so already and this is a local storage area,
 108   // will attempt to read any values for this origin currently
 109   // stored on disk.
 110   void InitialImportIfNeeded();
 111
 112   // Post tasks to defer writing a batch of changed values to
 113   // disk on the commit sequence, and to call back on the primary
 114   // task sequence when complete.
 115   CommitBatch* CreateCommitBatchIfNeeded();
 116   void OnCommitTimer();
 117   void CommitChanges(const CommitBatch* commit_batch);
 118   void OnCommitComplete();
 119
 120   void ShutdownInCommitSequence();
 121
 122   int64 namespace_id_;
 123   std::string persistent_namespace_id_;
 124   GURL origin_;
 125   base::FilePath directory_;
 126   scoped_refptr<DomStorageTaskRunner> task_runner_;
 127   scoped_refptr<DomStorageMap> map_;
 128   scoped_ptr<DomStorageDatabaseAdapter> backing_;
 129   scoped_refptr<SessionStorageDatabase> session_storage_backing_;
 130   bool is_initial_import_done_;
 131   bool is_shutdown_;
 132   scoped_ptr<CommitBatch> commit_batch_;
 133   int commit_batches_in_flight_;
 134 };
 135
 136 }  // namespace dom_storage
 137
 138 #endif  // WEBKIT_DOM_STORAGE_DOM_STORAGE_AREA_H_