1// Copyright 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 CONTENT_BROWSER_DOM_STORAGE_DOM_STORAGE_AREA_H_
6#define CONTENT_BROWSER_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/strings/nullable_string16.h"
13#include "base/strings/string16.h"
14#include "content/common/content_export.h"
15#include "content/common/dom_storage/dom_storage_types.h"
16#include "url/gurl.h"
17
18namespace content {
19
20class DOMStorageDatabaseAdapter;
21class DOMStorageMap;
22class DOMStorageTaskRunner;
23class 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 DOMStorageContextImpl for a larger overview.
28class CONTENT_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(DOMStorageValuesMap* map);
53
54  unsigned Length();
55  base::NullableString16 Key(unsigned index);
56  base::NullableString16 GetItem(const base::string16& key);
57  bool SetItem(const base::string16& key, const base::string16& value,
58               base::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(DOMStorageContextImplTest, PersistentIds);
96  friend class base::RefCountedThreadSafe<DOMStorageArea>;
97
98  struct CommitBatch {
99    bool clear_all_first;
100    DOMStorageValuesMap 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 content
137
138#endif  // CONTENT_BROWSER_DOM_STORAGE_DOM_STORAGE_AREA_H_
139