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      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 
     18 namespace content {
     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 DOMStorageContextImpl for a larger overview.
     28 class 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