CallbackDataSource.h revision d49dbd6b625cddb82f3f7bbeac62d48ef338ef0f 
1/*
2 * Copyright 2015 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 ANDROID_CALLBACKDATASOURCE_H
18#define ANDROID_CALLBACKDATASOURCE_H
19
20#include <media/stagefright/DataSource.h>
21#include <media/stagefright/foundation/ADebug.h>
22
23namespace android {
24
25class IDataSource;
26class IMemory;
27
28// A stagefright DataSource that wraps a binder IDataSource. It's a "Callback"
29// DataSource because it calls back to the IDataSource for data.
30class CallbackDataSource : public DataSource {
31public:
32    explicit CallbackDataSource(const sp<IDataSource>& iDataSource);
33    virtual ~CallbackDataSource();
34
35    // DataSource implementation.
36    virtual status_t initCheck() const;
37    virtual ssize_t readAt(off64_t offset, void *data, size_t size);
38    virtual status_t getSize(off64_t *size);
39    virtual uint32_t flags();
40    virtual void close();
41    virtual String8 toString() {
42        return mName;
43    }
44    virtual sp<DecryptHandle> DrmInitialization(const char *mime = NULL);
45    virtual sp<IDataSource> getIDataSource() const;
46
47private:
48    sp<IDataSource> mIDataSource;
49    sp<IMemory> mMemory;
50    bool mIsClosed;
51    String8 mName;
52
53    DISALLOW_EVIL_CONSTRUCTORS(CallbackDataSource);
54};
55
56
57// A caching DataSource that wraps a CallbackDataSource. For reads smaller
58// than kCacheSize it will read up to kCacheSize ahead and cache it.
59// This reduces the number of binder round trips to the IDataSource and has a significant
60// impact on time taken for filetype sniffing and metadata extraction.
61class TinyCacheSource : public DataSource {
62public:
63    explicit TinyCacheSource(const sp<DataSource>& source);
64
65    virtual status_t initCheck() const;
66    virtual ssize_t readAt(off64_t offset, void* data, size_t size);
67    virtual status_t getSize(off64_t* size);
68    virtual uint32_t flags();
69    virtual void close() { mSource->close(); }
70    virtual String8 toString() {
71        return mName;
72    }
73    virtual sp<DecryptHandle> DrmInitialization(const char *mime = NULL);
74    virtual sp<IDataSource> getIDataSource() const;
75
76private:
77    // 2kb comes from experimenting with the time-to-first-frame from a MediaPlayer
78    // with an in-memory MediaDataSource source on a Nexus 5. Beyond 2kb there was
79    // no improvement.
80    enum {
81        kCacheSize = 2048,
82    };
83
84    sp<DataSource> mSource;
85    uint8_t mCache[kCacheSize];
86    off64_t mCachedOffset;
87    size_t mCachedSize;
88    String8 mName;
89
90    DISALLOW_EVIL_CONSTRUCTORS(TinyCacheSource);
91};
92
93}; // namespace android
94
95#endif // ANDROID_CALLBACKDATASOURCE_H
96