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 17 #ifndef ANDROID_GUI_DISPLAY_EVENT_H 18 #define ANDROID_GUI_DISPLAY_EVENT_H 19 20 #include <stdint.h> 21 #include <sys/types.h> 22 23 #include <utils/Errors.h> 24 #include <utils/RefBase.h> 25 #include <utils/Timers.h> 26 27 #include <binder/IInterface.h> 28 29 // ---------------------------------------------------------------------------- 30 31 namespace android { 32 33 // ---------------------------------------------------------------------------- 34 35 class BitTube; 36 class IDisplayEventConnection; 37 38 // ---------------------------------------------------------------------------- 39 40 class DisplayEventReceiver { 41 public: 42 enum { 43 DISPLAY_EVENT_VSYNC = 'vsyn', 44 DISPLAY_EVENT_HOTPLUG = 'plug' 45 }; 46 47 struct Event { 48 49 struct Header { 50 uint32_t type; 51 uint32_t id; 52 nsecs_t timestamp __attribute__((aligned(8))); 53 }; 54 55 struct VSync { 56 uint32_t count; 57 }; 58 59 struct Hotplug { 60 bool connected; 61 }; 62 63 Header header; 64 union { 65 VSync vsync; 66 Hotplug hotplug; 67 }; 68 }; 69 70 public: 71 /* 72 * DisplayEventReceiver creates and registers an event connection with 73 * SurfaceFlinger. VSync events are disabled by default. Call setVSyncRate 74 * or requestNextVsync to receive them. 75 * Other events start being delivered immediately. 76 */ 77 DisplayEventReceiver(); 78 79 /* 80 * ~DisplayEventReceiver severs the connection with SurfaceFlinger, new events 81 * stop being delivered immediately. Note that the queue could have 82 * some events pending. These will be delivered. 83 */ 84 ~DisplayEventReceiver(); 85 86 /* 87 * initCheck returns the state of DisplayEventReceiver after construction. 88 */ 89 status_t initCheck() const; 90 91 /* 92 * getFd returns the file descriptor to use to receive events. 93 * OWNERSHIP IS RETAINED by DisplayEventReceiver. DO NOT CLOSE this 94 * file-descriptor. 95 */ 96 int getFd() const; 97 98 /* 99 * getEvents reads events from the queue and returns how many events were 100 * read. Returns 0 if there are no more events or a negative error code. 101 * If NOT_ENOUGH_DATA is returned, the object has become invalid forever, it 102 * should be destroyed and getEvents() shouldn't be called again. 103 */ 104 ssize_t getEvents(Event* events, size_t count); 105 static ssize_t getEvents(const sp<BitTube>& dataChannel, 106 Event* events, size_t count); 107 108 /* 109 * sendEvents write events to the queue and returns how many events were 110 * written. 111 */ 112 static ssize_t sendEvents(const sp<BitTube>& dataChannel, 113 Event const* events, size_t count); 114 115 /* 116 * setVsyncRate() sets the Event::VSync delivery rate. A value of 117 * 1 returns every Event::VSync. A value of 2 returns every other event, 118 * etc... a value of 0 returns no event unless requestNextVsync() has 119 * been called. 120 */ 121 status_t setVsyncRate(uint32_t count); 122 123 /* 124 * requestNextVsync() schedules the next Event::VSync. It has no effect 125 * if the vsync rate is > 0. 126 */ 127 status_t requestNextVsync(); 128 129 private: 130 sp<IDisplayEventConnection> mEventConnection; 131 sp<BitTube> mDataChannel; 132 }; 133 134 // ---------------------------------------------------------------------------- 135 }; // namespace android 136 137 #endif // ANDROID_GUI_DISPLAY_EVENT_H 138