webkit/dom_storage/dom_storage_database.h

   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_DOM_STORAGE_DOM_STORAGE_DATABASE_H_
   6 #define WEBKIT_DOM_STORAGE_DOM_STORAGE_DATABASE_H_
   7
   8 #include <map>
   9
  10 #include "base/files/file_path.h"
  11 #include "base/gtest_prod_util.h"
  12 #include "base/memory/scoped_ptr.h"
  13 #include "base/nullable_string16.h"
  14 #include "base/string16.h"
  15 #include "sql/connection.h"
  16 #include "webkit/dom_storage/dom_storage_types.h"
  17 #include "webkit/storage/webkit_storage_export.h"
  18
  19 namespace dom_storage {
  20
  21 // Represents a SQLite based backing for DOM storage data. This
  22 // class is designed to be used on a single thread.
  23 class WEBKIT_STORAGE_EXPORT DomStorageDatabase {
  24  public:
  25   static base::FilePath GetJournalFilePath(const base::FilePath& database_path);
  26
  27   explicit DomStorageDatabase(const base::FilePath& file_path);
  28   virtual ~DomStorageDatabase();  // virtual for unit testing
  29
  30   // Reads all the key, value pairs stored in the database and returns
  31   // them. |result| is assumed to be empty and any duplicate keys will
  32   // be overwritten. If the database exists on disk then it will be
  33   // opened. If it does not exist then it will not be created and
  34   // |result| will be unmodified.
  35   void ReadAllValues(ValuesMap* result);
  36
  37   // Updates the backing database. Will remove all keys before updating
  38   // the database if |clear_all_first| is set. Then all entries in
  39   // |changes| will be examined - keys mapped to a null NullableString16
  40   // will be removed and all others will be inserted/updated as appropriate.
  41   bool CommitChanges(bool clear_all_first, const ValuesMap& changes);
  42
  43   // Simple getter for the path we were constructed with.
  44   const base::FilePath& file_path() const { return file_path_; }
  45
  46  protected:
  47   // Constructor that uses an in-memory sqlite database, for testing.
  48   DomStorageDatabase();
  49
  50  private:
  51   friend class LocalStorageDatabaseAdapter;
  52   FRIEND_TEST_ALL_PREFIXES(DomStorageDatabaseTest, SimpleOpenAndClose);
  53   FRIEND_TEST_ALL_PREFIXES(DomStorageDatabaseTest, TestLazyOpenIsLazy);
  54   FRIEND_TEST_ALL_PREFIXES(DomStorageDatabaseTest, TestDetectSchemaVersion);
  55   FRIEND_TEST_ALL_PREFIXES(DomStorageDatabaseTest,
  56                            TestLazyOpenUpgradesDatabase);
  57   FRIEND_TEST_ALL_PREFIXES(DomStorageDatabaseTest, SimpleWriteAndReadBack);
  58   FRIEND_TEST_ALL_PREFIXES(DomStorageDatabaseTest, WriteWithClear);
  59   FRIEND_TEST_ALL_PREFIXES(DomStorageDatabaseTest,
  60                            UpgradeFromV1ToV2WithData);
  61   FRIEND_TEST_ALL_PREFIXES(DomStorageDatabaseTest, TestSimpleRemoveOneValue);
  62   FRIEND_TEST_ALL_PREFIXES(DomStorageDatabaseTest,
  63                            TestCanOpenAndReadWebCoreDatabase);
  64   FRIEND_TEST_ALL_PREFIXES(DomStorageDatabaseTest,
  65                            TestCanOpenFileThatIsNotADatabase);
  66   FRIEND_TEST_ALL_PREFIXES(DomStorageAreaTest, BackingDatabaseOpened);
  67   FRIEND_TEST_ALL_PREFIXES(DomStorageAreaTest, CommitTasks);
  68   FRIEND_TEST_ALL_PREFIXES(DomStorageAreaTest, PurgeMemory);
  69
  70   enum SchemaVersion {
  71     INVALID,
  72     V1,
  73     V2
  74   };
  75
  76   // Open the database at file_path_ if it exists already and creates it if
  77   // |create_if_needed| is true.
  78   // Ensures we are at the correct database version and creates or updates
  79   // tables as necessary. Returns false on failure.
  80   bool LazyOpen(bool create_if_needed);
  81
  82   // Analyses the database to verify that the connection that is open is indeed
  83   // a valid database and works out the schema version.
  84   SchemaVersion DetectSchemaVersion();
  85
  86   // Creates the database table at V2. Returns true if the table was created
  87   // successfully, false otherwise. Will return false if the table already
  88   // exists.
  89   bool CreateTableV2();
  90
  91   // If we have issues while trying to open the file (corrupted databse,
  92   // failing to upgrade, that sort of thing) this function will remove
  93   // the file from disk and attempt to create a new database from
  94   // scratch.
  95   bool DeleteFileAndRecreate();
  96
  97   // Version 1 -> 2 migrates the value column in the ItemTable from a TEXT
  98   // to a BLOB. Exisitng data is preserved on success. Returns false if the
  99   // upgrade failed. If true is returned, the database is guaranteed to be at
 100   // version 2.
 101   bool UpgradeVersion1To2();
 102
 103   void Close();
 104   bool IsOpen() const { return db_.get() ? db_->is_open() : false; }
 105
 106   // Initialization code shared between the two constructors of this class.
 107   void Init();
 108
 109   // Path to the database on disk.
 110   const base::FilePath file_path_;
 111   scoped_ptr<sql::Connection> db_;
 112   bool failed_to_open_;
 113   bool tried_to_recreate_;
 114   bool known_to_be_empty_;
 115 };
 116
 117 }  // namespace dom_storage
 118
 119 #endif  // WEBKIT_DOM_STORAGE_DOM_STORAGE_DATABASE_H_