1/*
2 * Copyright 2010, The Android Open Source Project
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 *  * Redistributions of source code must retain the above copyright
8 *    notice, this list of conditions and the following disclaimer.
9 *  * Redistributions in binary form must reproduce the above copyright
10 *    notice, this list of conditions and the following disclaimer in the
11 *    documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS ``AS IS'' AND ANY
14 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
16 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR
17 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
18 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
19 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
20 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
21 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
23 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24 */
25
26#ifndef GeolocationPositionCache_h
27#define GeolocationPositionCache_h
28
29#include "PlatformString.h"
30#include "ScriptExecutionContext.h"
31
32#include <wtf/Forward.h>
33#include <wtf/MessageQueue.h>
34#include <wtf/PassRefPtr.h>
35#include <wtf/RefPtr.h>
36
37namespace WebCore {
38
39class Geoposition;
40
41// Maintains a cached position for Geolocation. Takes care of writing and
42// reading the position to a database on a background thread. The Geolocation
43// spec does not require a cached position to be maintained, so we take a
44// best-effort approach where we do not wait for database reads or writes.
45class GeolocationPositionCache {
46public:
47    static GeolocationPositionCache* instance();
48
49    void addUser();
50    void removeUser();
51
52    void setDatabasePath(const String&);
53    void setCachedPosition(Geoposition*);
54    Geoposition* cachedPosition();
55
56private:
57    GeolocationPositionCache();
58
59    void startBackgroundThread();
60    static void* threadEntryPoint(void* object);
61    void threadEntryPointImpl();
62
63    void triggerReadFromDatabase();
64    static void readFromDatabase(ScriptExecutionContext*, GeolocationPositionCache*);
65    void readFromDatabaseImpl();
66    void triggerWriteToDatabase();
67    static void writeToDatabase(ScriptExecutionContext*, GeolocationPositionCache*);
68    void writeToDatabaseImpl();
69
70    RefPtr<Geoposition> m_cachedPosition;
71    Mutex m_cachedPositionMutex;
72    ThreadIdentifier m_threadId;
73    MessageQueue<ScriptExecutionContext::Task> m_queue;
74    String m_databaseFile;
75    Mutex m_databaseFileMutex;
76};
77
78} // namespace WebCore
79
80#endif // GeolocationPositionCache_h
81