NuCachedSource2.h revision bff07d0b22a5ee2d9f044f6cb5e4be1532017ab0 
1/*
2 * Copyright (C) 2010 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#ifndef NU_CACHED_SOURCE_2_H_
18
19#define NU_CACHED_SOURCE_2_H_
20
21#include <media/stagefright/foundation/ABase.h>
22#include <media/stagefright/foundation/AHandlerReflector.h>
23#include <media/stagefright/DataSource.h>
24
25namespace android {
26
27struct ALooper;
28struct PageCache;
29
30struct NuCachedSource2 : public DataSource {
31    NuCachedSource2(const sp<DataSource> &source);
32
33    virtual status_t initCheck() const;
34
35    virtual ssize_t readAt(off_t offset, void *data, size_t size);
36
37    virtual status_t getSize(off_t *size);
38    virtual uint32_t flags();
39
40    ////////////////////////////////////////////////////////////////////////////
41
42    size_t cachedSize();
43    size_t approxDataRemaining(bool *eos);
44
45    void suspend();
46    void clearCacheAndResume();
47
48protected:
49    virtual ~NuCachedSource2();
50
51private:
52    friend struct AHandlerReflector<NuCachedSource2>;
53
54    enum {
55        kPageSize            = 65536,
56        kHighWaterThreshold  = 5 * 1024 * 1024,
57        kLowWaterThreshold   = 512 * 1024,
58
59        // Read data after a 15 sec timeout whether we're actively
60        // fetching or not.
61        kKeepAliveIntervalUs = 15000000,
62    };
63
64    enum {
65        kWhatFetchMore  = 'fetc',
66        kWhatRead       = 'read',
67        kWhatSuspend    = 'susp',
68    };
69
70    sp<DataSource> mSource;
71    sp<AHandlerReflector<NuCachedSource2> > mReflector;
72    sp<ALooper> mLooper;
73
74    Mutex mSerializer;
75    Mutex mLock;
76    Condition mCondition;
77
78    PageCache *mCache;
79    off_t mCacheOffset;
80    status_t mFinalStatus;
81    off_t mLastAccessPos;
82    sp<AMessage> mAsyncResult;
83    bool mFetching;
84    int64_t mLastFetchTimeUs;
85    bool mSuspended;
86
87    void onMessageReceived(const sp<AMessage> &msg);
88    void onFetch();
89    void onRead(const sp<AMessage> &msg);
90    void onSuspend();
91
92    void fetchInternal();
93    ssize_t readInternal(off_t offset, void *data, size_t size);
94    status_t seekInternal_l(off_t offset);
95
96    size_t approxDataRemaining_l(bool *eos);
97    void restartPrefetcherIfNecessary_l();
98
99    DISALLOW_EVIL_CONSTRUCTORS(NuCachedSource2);
100};
101
102}  // namespace android
103
104#endif  // NU_CACHED_SOURCE_2_H_
105