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