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Diffstat (limited to 'include/ui/InputTransport.h')
| -rw-r--r-- | include/ui/InputTransport.h | 336 |
1 files changed, 336 insertions, 0 deletions
diff --git a/include/ui/InputTransport.h b/include/ui/InputTransport.h new file mode 100644 index 000000000000..82831e29b6fc --- /dev/null +++ b/include/ui/InputTransport.h @@ -0,0 +1,336 @@ +/* + * Copyright (C) 2010 The Android Open Source Project + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +#ifndef _UI_INPUT_TRANSPORT_H +#define _UI_INPUT_TRANSPORT_H + +/** + * Native input transport. + * + * Uses anonymous shared memory as a whiteboard for sending input events from an + * InputPublisher to an InputConsumer and ensuring appropriate synchronization. + * One interesting feature is that published events can be updated in place as long as they + * have not yet been consumed. + * + * The InputPublisher and InputConsumer only take care of transferring event data + * over an InputChannel and sending synchronization signals. The InputDispatcher and InputQueue + * build on these abstractions to add multiplexing and queueing. + */ + +#include <semaphore.h> +#include <ui/Input.h> +#include <utils/Errors.h> +#include <utils/PollLoop.h> +#include <utils/Timers.h> +#include <utils/RefBase.h> +#include <utils/String8.h> + +namespace android { + +/* + * An input channel consists of a shared memory buffer and a pair of pipes + * used to send input messages from an InputPublisher to an InputConsumer + * across processes. Each channel has a descriptive name for debugging purposes. + * + * Each endpoint has its own InputChannel object that specifies its own file descriptors. + * + * The input channel is closed when all references to it are released. + */ +class InputChannel : public RefBase { +protected: + virtual ~InputChannel(); + +public: + InputChannel(const String8& name, int32_t ashmemFd, int32_t receivePipeFd, + int32_t sendPipeFd); + + /* Creates a pair of input channels and their underlying shared memory buffers + * and pipes. + * + * Returns OK on success. + */ + static status_t openInputChannelPair(const String8& name, + sp<InputChannel>& outServerChannel, sp<InputChannel>& outClientChannel); + + inline String8 getName() const { return mName; } + inline int32_t getAshmemFd() const { return mAshmemFd; } + inline int32_t getReceivePipeFd() const { return mReceivePipeFd; } + inline int32_t getSendPipeFd() const { return mSendPipeFd; } + + /* Sends a signal to the other endpoint. + * + * Returns OK on success. + * Returns DEAD_OBJECT if the channel's peer has been closed. + * Other errors probably indicate that the channel is broken. + */ + status_t sendSignal(char signal); + + /* Receives a signal send by the other endpoint. + * (Should only call this after poll() indicates that the receivePipeFd has available input.) + * + * Returns OK on success. + * Returns WOULD_BLOCK if there is no signal present. + * Returns DEAD_OBJECT if the channel's peer has been closed. + * Other errors probably indicate that the channel is broken. + */ + status_t receiveSignal(char* outSignal); + +private: + String8 mName; + int32_t mAshmemFd; + int32_t mReceivePipeFd; + int32_t mSendPipeFd; +}; + +/* + * Private intermediate representation of input events as messages written into an + * ashmem buffer. + */ +struct InputMessage { + /* Semaphore count is set to 1 when the message is published. + * It becomes 0 transiently while the publisher updates the message. + * It becomes 0 permanently when the consumer consumes the message. + */ + sem_t semaphore; + + /* Initialized to false by the publisher. + * Set to true by the consumer when it consumes the message. + */ + bool consumed; + + int32_t type; + + struct SampleData { + nsecs_t eventTime; + PointerCoords coords[0]; // variable length + }; + + int32_t deviceId; + int32_t source; + + union { + struct { + int32_t action; + int32_t flags; + int32_t keyCode; + int32_t scanCode; + int32_t metaState; + int32_t repeatCount; + nsecs_t downTime; + nsecs_t eventTime; + } key; + + struct { + int32_t action; + int32_t flags; + int32_t metaState; + int32_t edgeFlags; + nsecs_t downTime; + float xOffset; + float yOffset; + float xPrecision; + float yPrecision; + size_t pointerCount; + int32_t pointerIds[MAX_POINTERS]; + size_t sampleCount; + SampleData sampleData[0]; // variable length + } motion; + }; + + /* Gets the number of bytes to add to step to the next SampleData object in a motion + * event message for a given number of pointers. + */ + static inline size_t sampleDataStride(size_t pointerCount) { + return sizeof(InputMessage::SampleData) + pointerCount * sizeof(PointerCoords); + } + + /* Adds the SampleData stride to the given pointer. */ + static inline SampleData* sampleDataPtrIncrement(SampleData* ptr, size_t stride) { + return reinterpret_cast<InputMessage::SampleData*>(reinterpret_cast<char*>(ptr) + stride); + } +}; + +/* + * Publishes input events to an anonymous shared memory buffer. + * Uses atomic operations to coordinate shared access with a single concurrent consumer. + */ +class InputPublisher { +public: + /* Creates a publisher associated with an input channel. */ + explicit InputPublisher(const sp<InputChannel>& channel); + + /* Destroys the publisher and releases its input channel. */ + ~InputPublisher(); + + /* Gets the underlying input channel. */ + inline sp<InputChannel> getChannel() { return mChannel; } + + /* Prepares the publisher for use. Must be called before it is used. + * Returns OK on success. + * + * This method implicitly calls reset(). */ + status_t initialize(); + + /* Resets the publisher to its initial state and unpins its ashmem buffer. + * Returns OK on success. + * + * Should be called after an event has been consumed to release resources used by the + * publisher until the next event is ready to be published. + */ + status_t reset(); + + /* Publishes a key event to the ashmem buffer. + * + * Returns OK on success. + * Returns INVALID_OPERATION if the publisher has not been reset. + */ + status_t publishKeyEvent( + int32_t deviceId, + int32_t source, + int32_t action, + int32_t flags, + int32_t keyCode, + int32_t scanCode, + int32_t metaState, + int32_t repeatCount, + nsecs_t downTime, + nsecs_t eventTime); + + /* Publishes a motion event to the ashmem buffer. + * + * Returns OK on success. + * Returns INVALID_OPERATION if the publisher has not been reset. + * Returns BAD_VALUE if pointerCount is less than 1 or greater than MAX_POINTERS. + */ + status_t publishMotionEvent( + int32_t deviceId, + int32_t source, + int32_t action, + int32_t flags, + int32_t edgeFlags, + int32_t metaState, + float xOffset, + float yOffset, + float xPrecision, + float yPrecision, + nsecs_t downTime, + nsecs_t eventTime, + size_t pointerCount, + const int32_t* pointerIds, + const PointerCoords* pointerCoords); + + /* Appends a motion sample to a motion event unless already consumed. + * + * Returns OK on success. + * Returns INVALID_OPERATION if the current event is not a AMOTION_EVENT_ACTION_MOVE event. + * Returns FAILED_TRANSACTION if the current event has already been consumed. + * Returns NO_MEMORY if the buffer is full and no additional samples can be added. + */ + status_t appendMotionSample( + nsecs_t eventTime, + const PointerCoords* pointerCoords); + + /* Sends a dispatch signal to the consumer to inform it that a new message is available. + * + * Returns OK on success. + * Errors probably indicate that the channel is broken. + */ + status_t sendDispatchSignal(); + + /* Receives the finished signal from the consumer in reply to the original dispatch signal. + * + * Returns OK on success. + * Returns WOULD_BLOCK if there is no signal present. + * Other errors probably indicate that the channel is broken. + */ + status_t receiveFinishedSignal(); + +private: + sp<InputChannel> mChannel; + + size_t mAshmemSize; + InputMessage* mSharedMessage; + bool mPinned; + bool mSemaphoreInitialized; + bool mWasDispatched; + + size_t mMotionEventPointerCount; + InputMessage::SampleData* mMotionEventSampleDataTail; + size_t mMotionEventSampleDataStride; + + status_t publishInputEvent( + int32_t type, + int32_t deviceId, + int32_t source); +}; + +/* + * Consumes input events from an anonymous shared memory buffer. + * Uses atomic operations to coordinate shared access with a single concurrent publisher. + */ +class InputConsumer { +public: + /* Creates a consumer associated with an input channel. */ + explicit InputConsumer(const sp<InputChannel>& channel); + + /* Destroys the consumer and releases its input channel. */ + ~InputConsumer(); + + /* Gets the underlying input channel. */ + inline sp<InputChannel> getChannel() { return mChannel; } + + /* Prepares the consumer for use. Must be called before it is used. */ + status_t initialize(); + + /* Consumes the input event in the buffer and copies its contents into + * an InputEvent object created using the specified factory. + * This operation will block if the publisher is updating the event. + * + * Returns OK on success. + * Returns INVALID_OPERATION if there is no currently published event. + * Returns NO_MEMORY if the event could not be created. + */ + status_t consume(InputEventFactoryInterface* factory, InputEvent** outEvent); + + /* Sends a finished signal to the publisher to inform it that the current message is + * finished processing. + * + * Returns OK on success. + * Errors probably indicate that the channel is broken. + */ + status_t sendFinishedSignal(); + + /* Receives the dispatched signal from the publisher. + * + * Returns OK on success. + * Returns WOULD_BLOCK if there is no signal present. + * Other errors probably indicate that the channel is broken. + */ + status_t receiveDispatchSignal(); + +private: + sp<InputChannel> mChannel; + + size_t mAshmemSize; + InputMessage* mSharedMessage; + + void populateKeyEvent(KeyEvent* keyEvent) const; + void populateMotionEvent(MotionEvent* motionEvent) const; +}; + +} // namespace android + +#endif // _UI_INPUT_TRANSPORT_H |