| // 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_ |
| #pragma once |
| |
| #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; |
| 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. |
| 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, |
| const GURL& origin, |
| ValuesMap* result); |
| |
| // Updates the data for |namespace_id| and |origin|. Will remove all keys |
| // before updating the database if |clear_all_first| is set. Then all entries |
| // in |changes| will be examined - keys mapped to a null NullableString16 will |
| // be removed and all others will be inserted/updated as appropriate. It is |
| // allowed to write data into a shallow copy created by CloneNamespace, and in |
| // that case the copy will be made deep before writing the values. |
| bool CommitAreaChanges(const std::string& namespace_id, |
| const GURL& origin, |
| bool clear_all_first, |
| const ValuesMap& changes); |
| |
| // Creates shallow copies of the areas for |namespace_id| and associates them |
| // with |new_namespace_id|. |
| bool CloneNamespace(const std::string& namespace_id, |
| const std::string& new_namespace_id); |
| |
| // 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); |
| |
| 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: |
| // - leveldb cannot open the database. |
| // - The database is in an inconsistent or errored state. |
| bool LazyOpen(bool create_if_needed); |
| |
| // Tries to open the database at file_path_, assigns |db| to point to the |
| // opened leveldb::DB instance. |
| leveldb::Status TryToOpen(leveldb::DB** db); |
| |
| // Returns true if the database is already open, false otherwise. |
| bool IsOpen() const; |
| |
| // Helpers for checking caller erros, invariants and database errors. All |
| // these return |ok|, for chaining. |
| bool CallerErrorCheck(bool ok) const; |
| bool ConsistencyCheck(bool ok); |
| bool DatabaseErrorCheck(bool ok); |
| |
| // Helper functions. All return true if the operation succeeded, and false if |
| // it failed (a database error or a consistency error). If the return type is |
| // void, the operation cannot fail. If they return false, ConsistencyCheck or |
| // DatabaseErrorCheck have already been called. |
| |
| // Creates a namespace for |namespace_id| and updates the next namespace id if |
| // needed. If |ok_if_exists| is false, checks that the namespace didn't exist |
| // before. |
| bool CreateNamespace(const std::string& namespace_id, |
| bool ok_if_exists, |
| leveldb::WriteBatch* batch); |
| |
| // Reads the areas assoiated with |namespace_id| and puts the (origin, map_id) |
| // pairs into |areas|. |
| bool GetAreasInNamespace(const std::string& namespace_id, |
| std::map<std::string, std::string>* areas); |
| |
| // Adds an association between |origin| and |map_id| into the namespace |
| // |namespace_id|. |
| void AddAreaToNamespace(const std::string& namespace_id, |
| const std::string& origin, |
| const std::string& map_id, |
| leveldb::WriteBatch* batch); |
| |
| // 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, |
| 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, |
| 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); |
| // Decreases the ref count of a map by |decrease|. If the ref count goes to 0, |
| // deletes the map. |
| bool DecreaseMapRefCount(const std::string& map_id, |
| int decrease, |
| leveldb::WriteBatch* batch); |
| |
| // Deletes all values in |map_id|. |
| bool ClearMap(const std::string& map_id, leveldb::WriteBatch* batch); |
| |
| // Breaks the association between (|namespace_id|, |origin|) and |map_id| and |
| // creates a new map for (|namespace_id|, |origin|). Copies the data from the |
| // old map if |copy_data| is true. |
| bool DeepCopyArea(const std::string& namespace_id, |
| const GURL& origin, |
| bool copy_data, |
| std::string* map_id, |
| leveldb::WriteBatch* batch); |
| |
| // Helper functions for creating the keys needed for the schema. |
| static std::string NamespaceStartKey(const std::string& namespace_id); |
| static std::string NamespaceKey(const std::string& namespace_id, |
| const std::string& origin); |
| static const char* NamespacePrefix(); |
| static std::string MapRefCountKey(const std::string& map_id); |
| static std::string MapKey(const std::string& map_id, const std::string& key); |
| static const char* NextMapIdKey(); |
| |
| scoped_ptr<leveldb::DB> db_; |
| FilePath file_path_; |
| |
| // For protecting the database opening code. |
| base::Lock db_lock_; |
| |
| // True if a database error has occurred (e.g., cannot read data). |
| 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_ |