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* Copyright (C) 2011 The Android Open Source Project
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* See the License for the specific language governing permissions and
* limitations under the License.
#include <sys/socket.h>
#include <common_time/ICommonClock.h>
namespace android {
class CommonTimeServer;
class CommonClockService : public BnCommonClock,
public android::IBinder::DeathRecipient {
static sp<CommonClockService> instantiate(CommonTimeServer& timeServer);
virtual status_t dump(int fd, const Vector<String16>& args);
virtual status_t isCommonTimeValid(bool* valid, uint32_t *timelineID);
virtual status_t commonTimeToLocalTime(int64_t common_time,
int64_t* local_time);
virtual status_t localTimeToCommonTime(int64_t local_time,
int64_t* common_time);
virtual status_t getCommonTime(int64_t* common_time);
virtual status_t getCommonFreq(uint64_t* freq);
virtual status_t getLocalTime(int64_t* local_time);
virtual status_t getLocalFreq(uint64_t* freq);
virtual status_t getEstimatedError(int32_t* estimate);
virtual status_t getTimelineID(uint64_t* id);
virtual status_t getState(ICommonClock::State* state);
virtual status_t getMasterAddr(struct sockaddr_storage* addr);
virtual status_t registerListener(
const sp<ICommonClockListener>& listener);
virtual status_t unregisterListener(
const sp<ICommonClockListener>& listener);
void notifyOnTimelineChanged(uint64_t timelineID);
CommonClockService(CommonTimeServer& timeServer)
: mTimeServer(timeServer) { };
virtual void binderDied(const wp<IBinder>& who);
CommonTimeServer& mTimeServer;
// locks used to synchronize access to the list of registered listeners.
// The callback lock is held whenever the list is used to perform callbacks
// or while the list is being modified. The registration lock used to
// serialize access across registerListener, unregisterListener, and
// binderDied.
// The reason for two locks is that registerListener, unregisterListener,
// and binderDied each call into the core service and obtain the core
// service thread lock when they call reevaluateAutoDisableState. The core
// service thread obtains the main thread lock whenever its thread is
// running, and sometimes needs to call notifyOnTimelineChanged which then
// obtains the callback lock. If callers of registration functions were
// holding the callback lock when they called into the core service, we
// would have a classic A/B, B/A ordering deadlock. To avoid this, the
// registration functions hold the registration lock for the duration of
// their call, but hold the callback lock only while they mutate the list.
// This way, the list's size cannot change (because of the registration
// lock) during the call into reevaluateAutoDisableState, but the core work
// thread can still safely call notifyOnTimelineChanged while holding the
// main thread lock.
Mutex mCallbackLock;
Mutex mRegistrationLock;
Vector<sp<ICommonClockListener> > mListeners;
}; // namespace android