DisplayEventReceiver.h revision d0566bc26fcf6ca396118701fa11900b627f2c09
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 31namespace android { 32 33// ---------------------------------------------------------------------------- 34 35class BitTube; 36class IDisplayEventConnection; 37 38// ---------------------------------------------------------------------------- 39 40class DisplayEventReceiver { 41public: 42 enum { 43 DISPLAY_EVENT_VSYNC = 'vsyn' 44 }; 45 46 struct Event { 47 48 struct Header { 49 uint32_t type; 50 nsecs_t timestamp; 51 }; 52 53 struct VSync { 54 uint32_t count; 55 }; 56 57 Header header; 58 union { 59 VSync vsync; 60 }; 61 }; 62 63public: 64 /* 65 * DisplayEventReceiver creates and registers an event connection with 66 * SurfaceFlinger. Events start being delivered immediately. 67 */ 68 DisplayEventReceiver(); 69 70 /* 71 * ~DisplayEventReceiver severs the connection with SurfaceFlinger, new events 72 * stop being delivered immediately. Note that the queue could have 73 * some events pending. These will be delivered. 74 */ 75 ~DisplayEventReceiver(); 76 77 /* 78 * initCheck returns the state of DisplayEventReceiver after construction. 79 */ 80 status_t initCheck() const; 81 82 /* 83 * getFd returns the file descriptor to use to receive events. 84 * OWNERSHIP IS RETAINED by DisplayEventReceiver. DO NOT CLOSE this 85 * file-descriptor. 86 */ 87 int getFd() const; 88 89 /* 90 * getEvents reads event from the queue and returns how many events were 91 * read. Returns 0 if there are no more events or a negative error code. 92 * If NOT_ENOUGH_DATA is returned, the object has become invalid forever, it 93 * should be destroyed and getEvents() shouldn't be called again. 94 */ 95 ssize_t getEvents(Event* events, size_t count); 96 97private: 98 sp<IDisplayEventConnection> mEventConnection; 99 sp<BitTube> mDataChannel; 100}; 101 102// ---------------------------------------------------------------------------- 103}; // namespace android 104 105#endif // ANDROID_GUI_DISPLAY_EVENT_H 106