/*
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* Copyright (C) 2011 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include "Configuration.h"
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#include "utils/threads.h"
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//--------------------------------------------------------------------------------------------------
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namespace android {
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class CallbackProtector : public RefBase {
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public:
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CallbackProtector();
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virtual ~CallbackProtector();
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/**
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* Indicates whether the CallbackProtector is non-NULL and it's safe to enter the callback.
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*/
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static bool enterCbIfOk(const sp<CallbackProtector> &protector);
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/**
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* Indicates whether it's safe to enter the callback. It would typically return false
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* if the associated object (AudioTrack, AudioPlayer, MediaPlayer) is about to be destroyed.
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*/
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bool enterCb();
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/**
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* This method must be paired to each call to enterCb() or enterCbIfOk(),
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* only it returned that it is safe enter the callback;
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*/
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void exitCb();
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/**
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* Called to signal the associated object is about to be destroyed, so whenever a callback is
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* entered (see enterCb) it will be notified it is pointless to process the callback. This will
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* return immediately if there are no callbacks, and will block until current callbacks exit.
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*/
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void requestCbExitAndWait();
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/**
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* Similar to requestCbExitAndWait, but does not wait for current callbacks to exit.
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*/
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void requestCbExit();
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private:
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Mutex mLock;
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Condition mCbExitedCondition;
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bool mSafeToEnterCb;
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/** Counts the number of callbacks actively locking the associated AudioPlayer */
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unsigned int mCbCount;
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#ifdef USE_DEBUG
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pthread_t mCallbackThread;
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pid_t mCallbackTid;
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pthread_t mRequesterThread;
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pid_t mRequesterTid;
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#endif
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// disallow "evil" constructors
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CallbackProtector(const CallbackProtector &);
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CallbackProtector &operator=(const CallbackProtector &);
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};
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} // namespace android
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