web_data_service_backend.h revision 7d4cd473f85ac64c3747c96c277f9e506a0d2246 
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 COMPONENTS_WEBDATA_COMMON_WEB_DATA_SERVICE_BACKEND_H_
6#define COMPONENTS_WEBDATA_COMMON_WEB_DATA_SERVICE_BACKEND_H_
7
8#include "base/basictypes.h"
9#include "base/callback_forward.h"
10#include "base/compiler_specific.h"
11#include "base/files/file_path.h"
12#include "base/memory/ref_counted.h"
13#include "base/memory/ref_counted_delete_on_message_loop.h"
14#include "base/memory/scoped_ptr.h"
15#include "base/memory/scoped_vector.h"
16#include "components/webdata/common/web_database_service.h"
17#include "components/webdata/common/webdata_export.h"
18
19class WebDatabase;
20class WebDatabaseTable;
21class WebDataRequest;
22class WebDataRequestManager;
23
24namespace tracked_objects {
25class Location;
26}
27
28// WebDataServiceBackend handles all database tasks posted by
29// WebDatabaseService. It is refcounted to allow asynchronous destruction on the
30// DB thread.
31
32// TODO(caitkp): Rename this class to WebDatabaseBackend.
33
34class WEBDATA_EXPORT WebDataServiceBackend
35    : public base::RefCountedDeleteOnMessageLoop<WebDataServiceBackend> {
36 public:
37  class Delegate {
38    public:
39    virtual ~Delegate() {}
40
41    // Invoked when the backend has finished loading the db.
42    virtual void DBLoaded(sql::InitStatus status) = 0;
43  };
44
45  WebDataServiceBackend(const base::FilePath& path,
46                        Delegate* delegate,
47                        const scoped_refptr<base::MessageLoopProxy>& db_thread);
48
49  // Must call only before InitDatabaseWithCallback.
50  void AddTable(scoped_ptr<WebDatabaseTable> table);
51
52  // Initializes the database and notifies caller via callback when complete.
53  // Callback is called synchronously.
54  void InitDatabase();
55
56  // Opens the database file from the profile path if an init has not yet been
57  // attempted. Separated from the constructor to ease construction/destruction
58  // of this object on one thread but database access on the DB thread. Returns
59  // the status of the database.
60  sql::InitStatus LoadDatabaseIfNecessary();
61
62  // Shuts down database. |should_reinit| tells us whether or not it should be
63  // possible to re-initialize the DB after the shutdown.
64  void ShutdownDatabase(bool should_reinit);
65
66  // Task wrappers to update requests and and notify |request_manager_|. These
67  // are used in cases where the request is being made from the UI thread and an
68  // asyncronous callback is required to notify the client of |request|'s
69  // completion.
70  void DBWriteTaskWrapper(
71      const WebDatabaseService::WriteTask& task,
72      scoped_ptr<WebDataRequest> request);
73  void DBReadTaskWrapper(
74      const WebDatabaseService::ReadTask& task,
75      scoped_ptr<WebDataRequest> request);
76
77  // Task runners to run database tasks.
78  void ExecuteWriteTask(const WebDatabaseService::WriteTask& task);
79  scoped_ptr<WDTypedResult> ExecuteReadTask(
80      const WebDatabaseService::ReadTask& task);
81
82  const scoped_refptr<WebDataRequestManager>& request_manager() {
83    return request_manager_;
84  }
85
86  WebDatabase* database() { return db_.get(); }
87
88 protected:
89  friend class base::RefCountedDeleteOnMessageLoop<WebDataServiceBackend>;
90  friend class base::DeleteHelper<WebDataServiceBackend>;
91
92  virtual ~WebDataServiceBackend();
93
94 private:
95  // Commit the current transaction.
96  void Commit();
97
98  // Path to database file.
99  base::FilePath db_path_;
100
101  // The tables that participate in managing the database. These are
102  // owned here but other than that this class does nothing with
103  // them. Their initialization is in whatever factory creates
104  // WebDatabaseService, and lookup by type is provided by the
105  // WebDatabase class. The tables need to be owned by this refcounted
106  // object, or they themselves would need to be refcounted. Owning
107  // them here rather than having WebDatabase own them makes for
108  // easier unit testing of WebDatabase.
109  ScopedVector<WebDatabaseTable> tables_;
110
111  scoped_ptr<WebDatabase> db_;
112
113  // Keeps track of all pending requests made to the db.
114  scoped_refptr<WebDataRequestManager> request_manager_;
115
116  // State of database initialization. Used to prevent the executing of tasks
117  // before the db is ready.
118  sql::InitStatus init_status_;
119
120  // True if an attempt has been made to load the database (even if the attempt
121  // fails), used to avoid continually trying to reinit if the db init fails.
122  bool init_complete_;
123
124  // Delegate. See the class definition above for more information.
125  scoped_ptr<Delegate> delegate_;
126
127  DISALLOW_COPY_AND_ASSIGN(WebDataServiceBackend);
128};
129
130#endif  // COMPONENTS_WEBDATA_COMMON_WEB_DATA_SERVICE_BACKEND_H_
131