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