1 /* 2 * Copyright (C) 2010 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 _UI_INPUT_TRANSPORT_H 18 #define _UI_INPUT_TRANSPORT_H 19 20 /** 21 * Native input transport. 22 * 23 * Uses anonymous shared memory as a whiteboard for sending input events from an 24 * InputPublisher to an InputConsumer and ensuring appropriate synchronization. 25 * One interesting feature is that published events can be updated in place as long as they 26 * have not yet been consumed. 27 * 28 * The InputPublisher and InputConsumer only take care of transferring event data 29 * over an InputChannel and sending synchronization signals. The InputDispatcher and InputQueue 30 * build on these abstractions to add multiplexing and queueing. 31 */ 32 33 #include <semaphore.h> 34 #include <ui/Input.h> 35 #include <utils/Errors.h> 36 #include <utils/Timers.h> 37 #include <utils/RefBase.h> 38 #include <utils/String8.h> 39 40 namespace android { 41 42 /* 43 * An input channel consists of a shared memory buffer and a pair of pipes 44 * used to send input messages from an InputPublisher to an InputConsumer 45 * across processes. Each channel has a descriptive name for debugging purposes. 46 * 47 * Each endpoint has its own InputChannel object that specifies its own file descriptors. 48 * 49 * The input channel is closed when all references to it are released. 50 */ 51 class InputChannel : public RefBase { 52 protected: 53 virtual ~InputChannel(); 54 55 public: 56 InputChannel(const String8& name, int32_t ashmemFd, int32_t receivePipeFd, 57 int32_t sendPipeFd); 58 59 /* Creates a pair of input channels and their underlying shared memory buffers 60 * and pipes. 61 * 62 * Returns OK on success. 63 */ 64 static status_t openInputChannelPair(const String8& name, 65 sp<InputChannel>& outServerChannel, sp<InputChannel>& outClientChannel); 66 67 inline String8 getName() const { return mName; } 68 inline int32_t getAshmemFd() const { return mAshmemFd; } 69 inline int32_t getReceivePipeFd() const { return mReceivePipeFd; } 70 inline int32_t getSendPipeFd() const { return mSendPipeFd; } 71 72 /* Sends a signal to the other endpoint. 73 * 74 * Returns OK on success. 75 * Returns DEAD_OBJECT if the channel's peer has been closed. 76 * Other errors probably indicate that the channel is broken. 77 */ 78 status_t sendSignal(char signal); 79 80 /* Receives a signal send by the other endpoint. 81 * (Should only call this after poll() indicates that the receivePipeFd has available input.) 82 * 83 * Returns OK on success. 84 * Returns WOULD_BLOCK if there is no signal present. 85 * Returns DEAD_OBJECT if the channel's peer has been closed. 86 * Other errors probably indicate that the channel is broken. 87 */ 88 status_t receiveSignal(char* outSignal); 89 90 private: 91 String8 mName; 92 int32_t mAshmemFd; 93 int32_t mReceivePipeFd; 94 int32_t mSendPipeFd; 95 }; 96 97 /* 98 * Private intermediate representation of input events as messages written into an 99 * ashmem buffer. 100 */ 101 struct InputMessage { 102 /* Semaphore count is set to 1 when the message is published. 103 * It becomes 0 transiently while the publisher updates the message. 104 * It becomes 0 permanently when the consumer consumes the message. 105 */ 106 sem_t semaphore; 107 108 /* Initialized to false by the publisher. 109 * Set to true by the consumer when it consumes the message. 110 */ 111 bool consumed; 112 113 int32_t type; 114 115 struct SampleData { 116 nsecs_t eventTime; 117 PointerCoords coords[0]; // variable length 118 }; 119 120 int32_t deviceId; 121 int32_t source; 122 123 union { 124 struct { 125 int32_t action; 126 int32_t flags; 127 int32_t keyCode; 128 int32_t scanCode; 129 int32_t metaState; 130 int32_t repeatCount; 131 nsecs_t downTime; 132 nsecs_t eventTime; 133 } key; 134 135 struct { 136 int32_t action; 137 int32_t flags; 138 int32_t metaState; 139 int32_t buttonState; 140 int32_t edgeFlags; 141 nsecs_t downTime; 142 float xOffset; 143 float yOffset; 144 float xPrecision; 145 float yPrecision; 146 size_t pointerCount; 147 PointerProperties pointerProperties[MAX_POINTERS]; 148 size_t sampleCount; 149 SampleData sampleData[0]; // variable length 150 } motion; 151 }; 152 153 /* Gets the number of bytes to add to step to the next SampleData object in a motion 154 * event message for a given number of pointers. 155 */ 156 static inline size_t sampleDataStride(size_t pointerCount) { 157 return sizeof(InputMessage::SampleData) + pointerCount * sizeof(PointerCoords); 158 } 159 160 /* Adds the SampleData stride to the given pointer. */ 161 static inline SampleData* sampleDataPtrIncrement(SampleData* ptr, size_t stride) { 162 return reinterpret_cast<InputMessage::SampleData*>(reinterpret_cast<char*>(ptr) + stride); 163 } 164 }; 165 166 /* 167 * Publishes input events to an anonymous shared memory buffer. 168 * Uses atomic operations to coordinate shared access with a single concurrent consumer. 169 */ 170 class InputPublisher { 171 public: 172 /* Creates a publisher associated with an input channel. */ 173 explicit InputPublisher(const sp<InputChannel>& channel); 174 175 /* Destroys the publisher and releases its input channel. */ 176 ~InputPublisher(); 177 178 /* Gets the underlying input channel. */ 179 inline sp<InputChannel> getChannel() { return mChannel; } 180 181 /* Prepares the publisher for use. Must be called before it is used. 182 * Returns OK on success. 183 * 184 * This method implicitly calls reset(). */ 185 status_t initialize(); 186 187 /* Resets the publisher to its initial state and unpins its ashmem buffer. 188 * Returns OK on success. 189 * 190 * Should be called after an event has been consumed to release resources used by the 191 * publisher until the next event is ready to be published. 192 */ 193 status_t reset(); 194 195 /* Publishes a key event to the ashmem buffer. 196 * 197 * Returns OK on success. 198 * Returns INVALID_OPERATION if the publisher has not been reset. 199 */ 200 status_t publishKeyEvent( 201 int32_t deviceId, 202 int32_t source, 203 int32_t action, 204 int32_t flags, 205 int32_t keyCode, 206 int32_t scanCode, 207 int32_t metaState, 208 int32_t repeatCount, 209 nsecs_t downTime, 210 nsecs_t eventTime); 211 212 /* Publishes a motion event to the ashmem buffer. 213 * 214 * Returns OK on success. 215 * Returns INVALID_OPERATION if the publisher has not been reset. 216 * Returns BAD_VALUE if pointerCount is less than 1 or greater than MAX_POINTERS. 217 */ 218 status_t publishMotionEvent( 219 int32_t deviceId, 220 int32_t source, 221 int32_t action, 222 int32_t flags, 223 int32_t edgeFlags, 224 int32_t metaState, 225 int32_t buttonState, 226 float xOffset, 227 float yOffset, 228 float xPrecision, 229 float yPrecision, 230 nsecs_t downTime, 231 nsecs_t eventTime, 232 size_t pointerCount, 233 const PointerProperties* pointerProperties, 234 const PointerCoords* pointerCoords); 235 236 /* Appends a motion sample to a motion event unless already consumed. 237 * 238 * Returns OK on success. 239 * Returns INVALID_OPERATION if the current event is not a AMOTION_EVENT_ACTION_MOVE event. 240 * Returns FAILED_TRANSACTION if the current event has already been consumed. 241 * Returns NO_MEMORY if the buffer is full and no additional samples can be added. 242 */ 243 status_t appendMotionSample( 244 nsecs_t eventTime, 245 const PointerCoords* pointerCoords); 246 247 /* Sends a dispatch signal to the consumer to inform it that a new message is available. 248 * 249 * Returns OK on success. 250 * Errors probably indicate that the channel is broken. 251 */ 252 status_t sendDispatchSignal(); 253 254 /* Receives the finished signal from the consumer in reply to the original dispatch signal. 255 * Returns whether the consumer handled the message. 256 * 257 * Returns OK on success. 258 * Returns WOULD_BLOCK if there is no signal present. 259 * Other errors probably indicate that the channel is broken. 260 */ 261 status_t receiveFinishedSignal(bool* outHandled); 262 263 private: 264 sp<InputChannel> mChannel; 265 266 size_t mAshmemSize; 267 InputMessage* mSharedMessage; 268 bool mPinned; 269 bool mSemaphoreInitialized; 270 bool mWasDispatched; 271 272 size_t mMotionEventPointerCount; 273 InputMessage::SampleData* mMotionEventSampleDataTail; 274 size_t mMotionEventSampleDataStride; 275 276 status_t publishInputEvent( 277 int32_t type, 278 int32_t deviceId, 279 int32_t source); 280 }; 281 282 /* 283 * Consumes input events from an anonymous shared memory buffer. 284 * Uses atomic operations to coordinate shared access with a single concurrent publisher. 285 */ 286 class InputConsumer { 287 public: 288 /* Creates a consumer associated with an input channel. */ 289 explicit InputConsumer(const sp<InputChannel>& channel); 290 291 /* Destroys the consumer and releases its input channel. */ 292 ~InputConsumer(); 293 294 /* Gets the underlying input channel. */ 295 inline sp<InputChannel> getChannel() { return mChannel; } 296 297 /* Prepares the consumer for use. Must be called before it is used. */ 298 status_t initialize(); 299 300 /* Consumes the input event in the buffer and copies its contents into 301 * an InputEvent object created using the specified factory. 302 * This operation will block if the publisher is updating the event. 303 * 304 * Returns OK on success. 305 * Returns INVALID_OPERATION if there is no currently published event. 306 * Returns NO_MEMORY if the event could not be created. 307 */ 308 status_t consume(InputEventFactoryInterface* factory, InputEvent** outEvent); 309 310 /* Sends a finished signal to the publisher to inform it that the current message is 311 * finished processing and specifies whether the message was handled by the consumer. 312 * 313 * Returns OK on success. 314 * Errors probably indicate that the channel is broken. 315 */ 316 status_t sendFinishedSignal(bool handled); 317 318 /* Receives the dispatched signal from the publisher. 319 * 320 * Returns OK on success. 321 * Returns WOULD_BLOCK if there is no signal present. 322 * Other errors probably indicate that the channel is broken. 323 */ 324 status_t receiveDispatchSignal(); 325 326 private: 327 sp<InputChannel> mChannel; 328 329 size_t mAshmemSize; 330 InputMessage* mSharedMessage; 331 332 void populateKeyEvent(KeyEvent* keyEvent) const; 333 void populateMotionEvent(MotionEvent* motionEvent) const; 334 }; 335 336 } // namespace android 337 338 #endif // _UI_INPUT_TRANSPORT_H 339
