components/webdata/common/web_database_table.h

   1 // Copyright (c) 2011 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 COMPONENTS_WEBDATA_COMMON_WEB_DATABASE_TABLE_H_
   6 #define COMPONENTS_WEBDATA_COMMON_WEB_DATABASE_TABLE_H_
   7
   8 #include "base/logging.h"
   9 #include "components/webdata/common/webdata_export.h"
  10
  11 namespace sql {
  12 class Connection;
  13 class MetaTable;
  14 }
  15
  16 // An abstract base class representing a table within a WebDatabase.
  17 // Each table should subclass this, adding type-specific methods as needed.
  18 class WEBDATA_EXPORT WebDatabaseTable {
  19  public:
  20   // To look up a WebDatabaseTable of a certain type from WebDatabase,
  21   // we use a void* key, so that we can simply use the address of one
  22   // of the type's statics.
  23   typedef void* TypeKey;
  24
  25   // The object is not ready for use until Init() has been called.
  26   WebDatabaseTable();
  27   virtual ~WebDatabaseTable();
  28
  29   // Retrieves the TypeKey for the concrete subtype.
  30   virtual TypeKey GetTypeKey() const = 0;
  31
  32   // Stores the passed members as instance variables.
  33   void Init(sql::Connection* db, sql::MetaTable* meta_table);
  34
  35   // Create all of the expected SQL tables if they do not already exist.
  36   // Returns true on success, false on failure.
  37   virtual bool CreateTablesIfNecessary() = 0;
  38
  39   // In order to encourage developers to think about sync when adding or
  40   // or altering new tables, this method must be implemented. Please get in
  41   // contact with the sync team if you believe you're making a change that they
  42   // should be aware of (or if you could break something).
  43   // TODO(andybons): Implement something more robust.
  44   virtual bool IsSyncable() = 0;
  45
  46   // Migrates this table to |version|. Returns false if there was
  47   // migration work to do and it failed, true otherwise.
  48   //
  49   // Implementations may set |*update_compatible_version| to true if
  50   // the compatible version should be changed to |version|.
  51   // Implementations should otherwise not modify this parameter.
  52   virtual bool MigrateToVersion(int version,
  53                                 bool* update_compatible_version) = 0;
  54
  55  protected:
  56   // Non-owning. These are owned by WebDatabase, valid as long as that
  57   // class exists. Since lifetime of WebDatabaseTable objects slightly
  58   // exceeds that of WebDatabase, they should not be used in
  59   // ~WebDatabaseTable.
  60   sql::Connection* db_;
  61   sql::MetaTable* meta_table_;
  62
  63  private:
  64   DISALLOW_COPY_AND_ASSIGN(WebDatabaseTable);
  65 };
  66
  67 #endif  // COMPONENTS_WEBDATA_COMMON_WEB_DATABASE_TABLE_H_