1 /* 2 * Copyright (C) 2016 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 namespace android { 18 19 // T is FastMixer or FastCapture 20 template<typename T> class AutoPark { 21 public: 22 23 // Park the specific FastThread, which can be nullptr, in hot idle if not currently idling AutoPark(const sp<T> & fastThread)24 AutoPark(const sp<T>& fastThread) : mFastThread(fastThread) 25 { 26 mPreviousCommand = FastThreadState::HOT_IDLE; 27 if (fastThread != nullptr) { 28 auto sq = mFastThread->sq(); 29 FastThreadState *state = sq->begin(); 30 if (!(state->mCommand & FastThreadState::IDLE)) { 31 mPreviousCommand = state->mCommand; 32 state->mCommand = FastThreadState::HOT_IDLE; 33 sq->end(); 34 sq->push(sq->BLOCK_UNTIL_ACKED); 35 } else { 36 sq->end(false /*didModify*/); 37 } 38 } 39 } 40 41 // Remove the FastThread from hot idle if necessary ~AutoPark()42 ~AutoPark() 43 { 44 if (!(mPreviousCommand & FastThreadState::IDLE)) { 45 ALOG_ASSERT(mFastThread != nullptr); 46 auto sq = mFastThread->sq(); 47 FastThreadState *state = sq->begin(); 48 ALOG_ASSERT(state->mCommand == FastThreadState::HOT_IDLE); 49 state->mCommand = mPreviousCommand; 50 sq->end(); 51 sq->push(sq->BLOCK_UNTIL_PUSHED); 52 } 53 } 54 55 private: 56 const sp<T> mFastThread; 57 // if !&IDLE, holds the FastThread state to restore after new parameters processed 58 FastThreadState::Command mPreviousCommand; 59 }; // class AutoPark 60 61 } // namespace 62