1 /* 2 * Copyright (C) 2012 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_FENCE_H 18 #define ANDROID_FENCE_H 19 20 #include <stdint.h> 21 #include <sys/types.h> 22 23 #include <ui/ANativeObjectBase.h> 24 #include <ui/PixelFormat.h> 25 #include <ui/Rect.h> 26 #include <utils/Flattenable.h> 27 #include <utils/String8.h> 28 #include <utils/Timers.h> 29 30 #include <experimental/optional> 31 32 struct ANativeWindowBuffer; 33 34 namespace android { 35 36 // =========================================================================== 37 // Fence 38 // =========================================================================== 39 40 class Fence 41 : public LightRefBase<Fence>, public Flattenable<Fence> 42 { 43 public: 44 static const sp<Fence> NO_FENCE; 45 46 // TIMEOUT_NEVER may be passed to the wait method to indicate that it 47 // should wait indefinitely for the fence to signal. 48 enum { TIMEOUT_NEVER = -1 }; 49 50 // Construct a new Fence object with an invalid file descriptor. This 51 // should be done when the Fence object will be set up by unflattening 52 // serialized data. 53 Fence(); 54 55 // Construct a new Fence object to manage a given fence file descriptor. 56 // When the new Fence object is destructed the file descriptor will be 57 // closed. 58 Fence(int fenceFd); 59 60 // Check whether the Fence has an open fence file descriptor. Most Fence 61 // methods treat an invalid file descriptor just like a valid fence that 62 // is already signalled, so using this is usually not necessary. isValid()63 bool isValid() const { return mFenceFd != -1; } 64 65 // wait waits for up to timeout milliseconds for the fence to signal. If 66 // the fence signals then NO_ERROR is returned. If the timeout expires 67 // before the fence signals then -ETIME is returned. A timeout of 68 // TIMEOUT_NEVER may be used to indicate that the call should wait 69 // indefinitely for the fence to signal. 70 status_t wait(int timeout); 71 72 // waitForever is a convenience function for waiting forever for a fence to 73 // signal (just like wait(TIMEOUT_NEVER)), but issuing an error to the 74 // system log and fence state to the kernel log if the wait lasts longer 75 // than a warning timeout. 76 // The logname argument should be a string identifying 77 // the caller and will be included in the log message. 78 status_t waitForever(const char* logname); 79 80 // merge combines two Fence objects, creating a new Fence object that 81 // becomes signaled when both f1 and f2 are signaled (even if f1 or f2 is 82 // destroyed before it becomes signaled). The name argument specifies the 83 // human-readable name to associated with the new Fence object. 84 static sp<Fence> merge(const char* name, const sp<Fence>& f1, 85 const sp<Fence>& f2); 86 87 static sp<Fence> merge(const String8& name, const sp<Fence>& f1, 88 const sp<Fence>& f2); 89 90 // Return a duplicate of the fence file descriptor. The caller is 91 // responsible for closing the returned file descriptor. On error, -1 will 92 // be returned and errno will indicate the problem. 93 int dup() const; 94 95 // getSignalTime returns the system monotonic clock time at which the 96 // fence transitioned to the signaled state. If the fence is not signaled 97 // then INT64_MAX is returned. If the fence is invalid or if an error 98 // occurs then -1 is returned. 99 nsecs_t getSignalTime() const; 100 101 #if __cplusplus > 201103L 102 // hasSignaled returns whether the fence has signaled yet. Prefer this to 103 // getSignalTime() or wait() if all you care about is whether the fence has 104 // signaled. Returns an optional bool, which will have a value if there was 105 // no error. hasSignaled()106 inline std::experimental::optional<bool> hasSignaled() { 107 // The sync_wait call underlying wait() has been measured to be 108 // significantly faster than the sync_fence_info call underlying 109 // getSignalTime(), which might otherwise appear to be the more obvious 110 // way to check whether a fence has signaled. 111 switch (wait(0)) { 112 case NO_ERROR: 113 return true; 114 case -ETIME: 115 return false; 116 default: 117 return {}; 118 } 119 } 120 #endif 121 122 // Flattenable interface 123 size_t getFlattenedSize() const; 124 size_t getFdCount() const; 125 status_t flatten(void*& buffer, size_t& size, int*& fds, size_t& count) const; 126 status_t unflatten(void const*& buffer, size_t& size, int const*& fds, size_t& count); 127 128 private: 129 // Only allow instantiation using ref counting. 130 friend class LightRefBase<Fence>; 131 ~Fence(); 132 133 // Disallow copying 134 Fence(const Fence& rhs); 135 Fence& operator = (const Fence& rhs); 136 const Fence& operator = (const Fence& rhs) const; 137 138 int mFenceFd; 139 }; 140 141 }; // namespace android 142 143 #endif // ANDROID_FENCE_H 144