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