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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_DATABASE_H_
      6 #define CONTENT_BROWSER_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/strings/nullable_string16.h"
     14 #include "base/strings/string16.h"
     15 #include "content/common/content_export.h"
     16 #include "content/common/dom_storage/dom_storage_types.h"
     17 #include "sql/connection.h"
     18 
     19 namespace content {
     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 CONTENT_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(DOMStorageValuesMap* 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 DOMStorageValuesMap& 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 content
    118 
    119 #endif  // CONTENT_BROWSER_DOM_STORAGE_DOM_STORAGE_DATABASE_H_
    120