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| 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_BROWSER_DOM_STORAGE_SESSION_STORAGE_DATABASE_H_ | |
| 6 #define WEBKIT_BROWSER_DOM_STORAGE_SESSION_STORAGE_DATABASE_H_ | |
| 7 | |
| 8 #include <map> | |
| 9 #include <string> | |
| 10 | |
| 11 #include "base/files/file_path.h" | |
| 12 #include "base/memory/ref_counted.h" | |
| 13 #include "base/memory/scoped_ptr.h" | |
| 14 #include "base/synchronization/lock.h" | |
| 15 #include "third_party/leveldatabase/src/include/leveldb/status.h" | |
| 16 #include "webkit/browser/webkit_storage_browser_export.h" | |
| 17 #include "webkit/common/dom_storage/dom_storage_types.h" | |
| 18 | |
| 19 class GURL; | |
| 20 | |
| 21 namespace leveldb { | |
| 22 class DB; | |
| 23 struct ReadOptions; | |
| 24 class WriteBatch; | |
| 25 } // namespace leveldb | |
| 26 | |
| 27 namespace dom_storage { | |
| 28 | |
| 29 // SessionStorageDatabase holds the data from multiple namespaces and multiple | |
| 30 // origins. All DomStorageAreas for session storage share the same | |
| 31 // SessionStorageDatabase. | |
| 32 | |
| 33 // Only one thread is allowed to call the public functions other than | |
| 34 // ReadAreaValues and ReadNamespacesAndOrigins. Other threads are allowed to | |
| 35 // call ReadAreaValues and ReadNamespacesAndOrigins. | |
| 36 class WEBKIT_STORAGE_BROWSER_EXPORT SessionStorageDatabase : | |
| 37 public base::RefCountedThreadSafe<SessionStorageDatabase> { | |
| 38 public: | |
| 39 explicit SessionStorageDatabase(const base::FilePath& file_path); | |
| 40 | |
| 41 // Reads the (key, value) pairs for |namespace_id| and |origin|. |result| is | |
| 42 // assumed to be empty and any duplicate keys will be overwritten. If the | |
| 43 // database exists on disk then it will be opened. If it does not exist then | |
| 44 // it will not be created and |result| will be unmodified. | |
| 45 void ReadAreaValues(const std::string& namespace_id, | |
| 46 const GURL& origin, | |
| 47 ValuesMap* result); | |
| 48 | |
| 49 // Updates the data for |namespace_id| and |origin|. Will remove all keys | |
| 50 // before updating the database if |clear_all_first| is set. Then all entries | |
| 51 // in |changes| will be examined - keys mapped to a null NullableString16 will | |
| 52 // be removed and all others will be inserted/updated as appropriate. It is | |
| 53 // allowed to write data into a shallow copy created by CloneNamespace, and in | |
| 54 // that case the copy will be made deep before writing the values. | |
| 55 bool CommitAreaChanges(const std::string& namespace_id, | |
| 56 const GURL& origin, | |
| 57 bool clear_all_first, | |
| 58 const ValuesMap& changes); | |
| 59 | |
| 60 // Creates shallow copies of the areas for |namespace_id| and associates them | |
| 61 // with |new_namespace_id|. | |
| 62 bool CloneNamespace(const std::string& namespace_id, | |
| 63 const std::string& new_namespace_id); | |
| 64 | |
| 65 // Deletes the data for |namespace_id| and |origin|. | |
| 66 bool DeleteArea(const std::string& namespace_id, const GURL& origin); | |
| 67 | |
| 68 // Deletes the data for |namespace_id|. | |
| 69 bool DeleteNamespace(const std::string& namespace_id); | |
| 70 | |
| 71 // Reads the namespace IDs and origins present in the database. | |
| 72 bool ReadNamespacesAndOrigins( | |
| 73 std::map<std::string, std::vector<GURL> >* namespaces_and_origins); | |
| 74 | |
| 75 private: | |
| 76 friend class base::RefCountedThreadSafe<SessionStorageDatabase>; | |
| 77 friend class SessionStorageDatabaseTest; | |
| 78 | |
| 79 ~SessionStorageDatabase(); | |
| 80 | |
| 81 // Opens the database at file_path_ if it exists already and creates it if | |
| 82 // |create_if_needed| is true. Returns true if the database was opened, false | |
| 83 // if the opening failed or was not necessary (the database doesn't exist and | |
| 84 // |create_if_needed| is false). The possible failures are: | |
| 85 // - leveldb cannot open the database. | |
| 86 // - The database is in an inconsistent or errored state. | |
| 87 bool LazyOpen(bool create_if_needed); | |
| 88 | |
| 89 // Tries to open the database at file_path_, assigns |db| to point to the | |
| 90 // opened leveldb::DB instance. | |
| 91 leveldb::Status TryToOpen(leveldb::DB** db); | |
| 92 | |
| 93 // Returns true if the database is already open, false otherwise. | |
| 94 bool IsOpen() const; | |
| 95 | |
| 96 // Helpers for checking caller erros, invariants and database errors. All | |
| 97 // these return |ok|, for chaining. | |
| 98 bool CallerErrorCheck(bool ok) const; | |
| 99 bool ConsistencyCheck(bool ok); | |
| 100 bool DatabaseErrorCheck(bool ok); | |
| 101 | |
| 102 // Helper functions. All return true if the operation succeeded, and false if | |
| 103 // it failed (a database error or a consistency error). If the return type is | |
| 104 // void, the operation cannot fail. If they return false, ConsistencyCheck or | |
| 105 // DatabaseErrorCheck have already been called. | |
| 106 | |
| 107 // Creates a namespace for |namespace_id| and updates the next namespace id if | |
| 108 // needed. If |ok_if_exists| is false, checks that the namespace didn't exist | |
| 109 // before. | |
| 110 bool CreateNamespace(const std::string& namespace_id, | |
| 111 bool ok_if_exists, | |
| 112 leveldb::WriteBatch* batch); | |
| 113 | |
| 114 // Reads the areas assoiated with |namespace_id| and puts the (origin, map_id) | |
| 115 // pairs into |areas|. | |
| 116 bool GetAreasInNamespace(const std::string& namespace_id, | |
| 117 std::map<std::string, std::string>* areas); | |
| 118 | |
| 119 // Adds an association between |origin| and |map_id| into the namespace | |
| 120 // |namespace_id|. | |
| 121 void AddAreaToNamespace(const std::string& namespace_id, | |
| 122 const std::string& origin, | |
| 123 const std::string& map_id, | |
| 124 leveldb::WriteBatch* batch); | |
| 125 | |
| 126 // Helpers for deleting data for |namespace_id| and |origin|. | |
| 127 bool DeleteAreaHelper(const std::string& namespace_id, | |
| 128 const std::string& origin, | |
| 129 leveldb::WriteBatch* batch); | |
| 130 | |
| 131 // Retrieves the map id for |namespace_id| and |origin|. It's not an error if | |
| 132 // the map doesn't exist. | |
| 133 bool GetMapForArea(const std::string& namespace_id, | |
| 134 const std::string& origin, | |
| 135 const leveldb::ReadOptions& options, | |
| 136 bool* exists, | |
| 137 std::string* map_id); | |
| 138 | |
| 139 // Creates a new map for |namespace_id| and |origin|. |map_id| will hold the | |
| 140 // id of the created map. If there is a map for |namespace_id| and |origin|, | |
| 141 // this just overwrites the map id. The caller is responsible for decreasing | |
| 142 // the ref count. | |
| 143 bool CreateMapForArea(const std::string& namespace_id, | |
| 144 const GURL& origin, | |
| 145 std::string* map_id, | |
| 146 leveldb::WriteBatch* batch); | |
| 147 // Reads the contents of the map |map_id| into |result|. If |only_keys| is | |
| 148 // true, only keys are aread from the database and the values in |result| will | |
| 149 // be empty. | |
| 150 bool ReadMap(const std::string& map_id, | |
| 151 const leveldb::ReadOptions& options, | |
| 152 ValuesMap* result, | |
| 153 bool only_keys); | |
| 154 // Writes |values| into the map |map_id|. | |
| 155 void WriteValuesToMap(const std::string& map_id, | |
| 156 const ValuesMap& values, | |
| 157 leveldb::WriteBatch* batch); | |
| 158 | |
| 159 bool GetMapRefCount(const std::string& map_id, int64* ref_count); | |
| 160 bool IncreaseMapRefCount(const std::string& map_id, | |
| 161 leveldb::WriteBatch* batch); | |
| 162 // Decreases the ref count of a map by |decrease|. If the ref count goes to 0, | |
| 163 // deletes the map. | |
| 164 bool DecreaseMapRefCount(const std::string& map_id, | |
| 165 int decrease, | |
| 166 leveldb::WriteBatch* batch); | |
| 167 | |
| 168 // Deletes all values in |map_id|. | |
| 169 bool ClearMap(const std::string& map_id, leveldb::WriteBatch* batch); | |
| 170 | |
| 171 // Breaks the association between (|namespace_id|, |origin|) and |map_id| and | |
| 172 // creates a new map for (|namespace_id|, |origin|). Copies the data from the | |
| 173 // old map if |copy_data| is true. | |
| 174 bool DeepCopyArea(const std::string& namespace_id, | |
| 175 const GURL& origin, | |
| 176 bool copy_data, | |
| 177 std::string* map_id, | |
| 178 leveldb::WriteBatch* batch); | |
| 179 | |
| 180 // Helper functions for creating the keys needed for the schema. | |
| 181 static std::string NamespaceStartKey(const std::string& namespace_id); | |
| 182 static std::string NamespaceKey(const std::string& namespace_id, | |
| 183 const std::string& origin); | |
| 184 static const char* NamespacePrefix(); | |
| 185 static std::string MapRefCountKey(const std::string& map_id); | |
| 186 static std::string MapKey(const std::string& map_id, const std::string& key); | |
| 187 static const char* NextMapIdKey(); | |
| 188 | |
| 189 scoped_ptr<leveldb::DB> db_; | |
| 190 base::FilePath file_path_; | |
| 191 | |
| 192 // For protecting the database opening code. | |
| 193 base::Lock db_lock_; | |
| 194 | |
| 195 // True if a database error has occurred (e.g., cannot read data). | |
| 196 bool db_error_; | |
| 197 // True if the database is in an inconsistent state. | |
| 198 bool is_inconsistent_; | |
| 199 | |
| 200 DISALLOW_COPY_AND_ASSIGN(SessionStorageDatabase); | |
| 201 }; | |
| 202 | |
| 203 } // namespace dom_storage | |
| 204 | |
| 205 #endif // WEBKIT_BROWSER_DOM_STORAGE_SESSION_STORAGE_DATABASE_H_ | |
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