Persist sessionStorage on disk.

webkit/dom_storage/session_storage_database.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef WEBKIT_DOM_STORAGE_SESSION_STORAGE_DATABASE_H_
 #define WEBKIT_DOM_STORAGE_SESSION_STORAGE_DATABASE_H_
 
 #include <map>
 #include <string>
 
 #include "base/file_path.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/synchronization/lock.h"
 #include "third_party/leveldatabase/src/include/leveldb/status.h"
 #include "webkit/dom_storage/dom_storage_types.h"
 
 class GURL;
 
 namespace leveldb {
 class DB;
+struct ReadOptions;
 class WriteBatch;
 }  // namespace leveldb
 
 namespace dom_storage {
 
 // SessionStorageDatabase holds the data from multiple namespaces and multiple
 // origins. All DomStorageAreas for session storage share the same
 // SessionStorageDatabase.
+
+// Only one thread is allowed to call the public functions other than
+// ReadAreaValues. Other threads area allowed to call ReadAreaValues.
 class SessionStorageDatabase :
     public base::RefCountedThreadSafe<SessionStorageDatabase> {
  public:
   explicit SessionStorageDatabase(const FilePath& file_path);
 
   // Reads the (key, value) pairs for |namespace_id| and |origin|. |result| is
   // assumed to be empty and any duplicate keys will be overwritten. If the
   // database exists on disk then it will be opened. If it does not exist then
   // it will not be created and |result| will be unmodified.
   void ReadAreaValues(const std::string& namespace_id,
@@ skipping 18 matching lines @@
 
   // Deletes the data for |namespace_id| and |origin|.
   bool DeleteArea(const std::string& namespace_id, const GURL& origin);
 
   // Deletes the data for |namespace_id|.
   bool DeleteNamespace(const std::string& namespace_id);
 
   // Reads all namespace IDs from the database.
   bool ReadNamespaceIds(std::vector<std::string>* namespace_ids);
 
+  // Reads all origins which have data stored in |namespace_id|.
+  bool ReadOriginsInNamespace(const std::string& namespace_id,
+                              std::vector<GURL>* origins);
+
  private:
   friend class base::RefCountedThreadSafe<SessionStorageDatabase>;
   friend class SessionStorageDatabaseTest;
 
   ~SessionStorageDatabase();
 
   // Opens the database at file_path_ if it exists already and creates it if
   // |create_if_needed| is true. Returns true if the database was opened, false
   // if the opening failed or was not necessary (the database doesn't exist and
   // |create_if_needed| is false). The possible failures are:
@@ skipping 40 matching lines @@
 
   // Helpers for deleting data for |namespace_id| and |origin|.
   bool DeleteAreaHelper(const std::string& namespace_id,
                         const std::string& origin,
                         leveldb::WriteBatch* batch);
 
   // Retrieves the map id for |namespace_id| and |origin|. It's not an error if
   // the map doesn't exist.
   bool GetMapForArea(const std::string& namespace_id,
                      const std::string& origin,
+                     const leveldb::ReadOptions& options,
                      bool* exists,
                      std::string* map_id);
 
   // Creates a new map for |namespace_id| and |origin|. |map_id| will hold the
   // id of the created map. If there is a map for |namespace_id| and |origin|,
   // this just overwrites the map id. The caller is responsible for decreasing
   // the ref count.
   bool CreateMapForArea(const std::string& namespace_id,
                         const GURL& origin,
                         std::string* map_id,
                         leveldb::WriteBatch* batch);
   // Reads the contents of the map |map_id| into |result|. If |only_keys| is
   // true, only keys are aread from the database and the values in |result| will
   // be empty.
   bool ReadMap(const std::string& map_id,
+               const leveldb::ReadOptions& options,
                ValuesMap* result,
                bool only_keys);
   // Writes |values| into the map |map_id|.
   void WriteValuesToMap(const std::string& map_id,
                         const ValuesMap& values,
                         leveldb::WriteBatch* batch);
 
   bool GetMapRefCount(const std::string& map_id, int64* ref_count);
   bool IncreaseMapRefCount(const std::string& map_id,
                            leveldb::WriteBatch* batch);
@@ skipping 34 matching lines @@
   bool db_error_;
   // True if the database is in an inconsistent state.
   bool is_inconsistent_;
 
   DISALLOW_COPY_AND_ASSIGN(SessionStorageDatabase);
 };
 
 }  // namespace dom_storage
 
 #endif  // WEBKIT_DOM_STORAGE_SESSION_STORAGE_DATABASE_H_