Mike J. Chen | 6c92951 | 2011-08-15 11:59:47 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2011 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 | |
Mike J. Chen | 6c92951 | 2011-08-15 11:59:47 -0700 | [diff] [blame] | 17 | #ifndef ANDROID_COMMON_CLOCK_SERVICE_H |
| 18 | #define ANDROID_COMMON_CLOCK_SERVICE_H |
| 19 | |
Elliott Hughes | 778c859 | 2012-09-11 18:50:25 -0700 | [diff] [blame] | 20 | #include <sys/socket.h> |
| 21 | #include <common_time/ICommonClock.h> |
| 22 | |
Mike J. Chen | 6c92951 | 2011-08-15 11:59:47 -0700 | [diff] [blame] | 23 | namespace android { |
| 24 | |
| 25 | class CommonTimeServer; |
| 26 | |
| 27 | class CommonClockService : public BnCommonClock, |
| 28 | public android::IBinder::DeathRecipient { |
| 29 | public: |
| 30 | static sp<CommonClockService> instantiate(CommonTimeServer& timeServer); |
| 31 | |
| 32 | virtual status_t dump(int fd, const Vector<String16>& args); |
| 33 | |
| 34 | virtual status_t isCommonTimeValid(bool* valid, uint32_t *timelineID); |
| 35 | virtual status_t commonTimeToLocalTime(int64_t common_time, |
| 36 | int64_t* local_time); |
| 37 | virtual status_t localTimeToCommonTime(int64_t local_time, |
| 38 | int64_t* common_time); |
| 39 | virtual status_t getCommonTime(int64_t* common_time); |
| 40 | virtual status_t getCommonFreq(uint64_t* freq); |
| 41 | virtual status_t getLocalTime(int64_t* local_time); |
| 42 | virtual status_t getLocalFreq(uint64_t* freq); |
| 43 | virtual status_t getEstimatedError(int32_t* estimate); |
| 44 | virtual status_t getTimelineID(uint64_t* id); |
| 45 | virtual status_t getState(ICommonClock::State* state); |
| 46 | virtual status_t getMasterAddr(struct sockaddr_storage* addr); |
| 47 | |
| 48 | virtual status_t registerListener( |
| 49 | const sp<ICommonClockListener>& listener); |
| 50 | virtual status_t unregisterListener( |
| 51 | const sp<ICommonClockListener>& listener); |
| 52 | |
| 53 | void notifyOnTimelineChanged(uint64_t timelineID); |
| 54 | |
| 55 | private: |
| 56 | CommonClockService(CommonTimeServer& timeServer) |
| 57 | : mTimeServer(timeServer) { }; |
| 58 | |
| 59 | virtual void binderDied(const wp<IBinder>& who); |
| 60 | |
| 61 | CommonTimeServer& mTimeServer; |
| 62 | |
| 63 | // locks used to synchronize access to the list of registered listeners. |
| 64 | // The callback lock is held whenever the list is used to perform callbacks |
| 65 | // or while the list is being modified. The registration lock used to |
| 66 | // serialize access across registerListener, unregisterListener, and |
| 67 | // binderDied. |
| 68 | // |
| 69 | // The reason for two locks is that registerListener, unregisterListener, |
| 70 | // and binderDied each call into the core service and obtain the core |
| 71 | // service thread lock when they call reevaluateAutoDisableState. The core |
| 72 | // service thread obtains the main thread lock whenever its thread is |
| 73 | // running, and sometimes needs to call notifyOnTimelineChanged which then |
| 74 | // obtains the callback lock. If callers of registration functions were |
| 75 | // holding the callback lock when they called into the core service, we |
| 76 | // would have a classic A/B, B/A ordering deadlock. To avoid this, the |
| 77 | // registration functions hold the registration lock for the duration of |
| 78 | // their call, but hold the callback lock only while they mutate the list. |
| 79 | // This way, the list's size cannot change (because of the registration |
| 80 | // lock) during the call into reevaluateAutoDisableState, but the core work |
| 81 | // thread can still safely call notifyOnTimelineChanged while holding the |
| 82 | // main thread lock. |
| 83 | Mutex mCallbackLock; |
| 84 | Mutex mRegistrationLock; |
| 85 | |
| 86 | Vector<sp<ICommonClockListener> > mListeners; |
| 87 | }; |
| 88 | |
| 89 | }; // namespace android |
| 90 | |
| 91 | #endif // ANDROID_COMMON_CLOCK_SERVICE_H |