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1 /*
2  * Copyright (C) 2010 Google Inc. All rights reserved.
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  *
8  * 1.  Redistributions of source code must retain the above copyright
9  *     notice, this list of conditions and the following disclaimer.
10  * 2.  Redistributions in binary form must reproduce the above copyright
11  *     notice, this list of conditions and the following disclaimer in the
12  *     documentation and/or other materials provided with the distribution.
13  * 3.  Neither the name of Apple Computer, Inc. ("Apple") nor the names of
14  *     its contributors may be used to endorse or promote products derived
15  *     from this software without specific prior written permission.
16  *
17  * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
18  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
19  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
20  * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
21  * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
22  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
23  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
24  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27  */
28 
29 #ifndef HRTFDatabaseLoader_h
30 #define HRTFDatabaseLoader_h
31 
32 #include "platform/audio/HRTFDatabase.h"
33 #include "public/platform/WebThread.h"
34 #include "wtf/HashMap.h"
35 #include "wtf/PassRefPtr.h"
36 #include "wtf/RefCounted.h"
37 #include "wtf/RefPtr.h"
38 #include "wtf/ThreadingPrimitives.h"
39 
40 namespace WebCore {
41 
42 // HRTFDatabaseLoader will asynchronously load the default HRTFDatabase in a new thread.
43 
44 class PLATFORM_EXPORT HRTFDatabaseLoader : public RefCounted<HRTFDatabaseLoader> {
45 public:
46     // Lazily creates a HRTFDatabaseLoader (if not already created) for the given sample-rate
47     // and starts loading asynchronously (when created the first time).
48     // Returns the HRTFDatabaseLoader.
49     // Must be called from the main thread.
50     static PassRefPtr<HRTFDatabaseLoader> createAndLoadAsynchronouslyIfNecessary(float sampleRate);
51 
52     // Both constructor and destructor must be called from the main thread.
53     ~HRTFDatabaseLoader();
54 
55     // Returns true once the default database has been completely loaded.
56     bool isLoaded() const;
57 
58     // waitForLoaderThreadCompletion() may be called more than once and is thread-safe.
59     void waitForLoaderThreadCompletion();
60 
database()61     HRTFDatabase* database() { return m_hrtfDatabase.get(); }
62 
databaseSampleRate()63     float databaseSampleRate() const { return m_databaseSampleRate; }
64 
65     // Called in asynchronous loading thread.
66     void load();
67 
68 private:
69     // Both constructor and destructor must be called from the main thread.
70     explicit HRTFDatabaseLoader(float sampleRate);
71 
72     // If it hasn't already been loaded, creates a new thread and initiates asynchronous loading of the default database.
73     // This must be called from the main thread.
74     void loadAsynchronously();
75 
76     // Map from sample-rate to loader.
77     typedef HashMap<double, HRTFDatabaseLoader*> LoaderMap;
78 
79     // Keeps track of loaders on a per-sample-rate basis.
80     static LoaderMap* s_loaderMap; // singleton
81 
82     OwnPtr<HRTFDatabase> m_hrtfDatabase;
83 
84     // Holding a m_threadLock is required when accessing m_databaseLoaderThread since we access it from multiple threads.
85     Mutex m_threadLock;
86     OwnPtr<blink::WebThread> m_databaseLoaderThread;
87 
88     float m_databaseSampleRate;
89 };
90 
91 } // namespace WebCore
92 
93 #endif // HRTFDatabaseLoader_h
94