replicant-frameworks_native/include/ui/InputTransport.h
Jeff Brown 59abe7e090 Replace epoll() with poll() and rename PollLoop to Looper.
As part of this change, consolidated and cleaned up the Looper API so
that there are fewer distinctions between the NDK and non-NDK declarations
(no need for two callback types, etc.).

Removed the dependence on specific constants from sys/poll.h such as
POLLIN.  Instead looper.h defines events like LOOPER_EVENT_INPUT for
the events that it supports.  That should help make any future
under-the-hood implementation changes easier.

Fixed a couple of compiler warnings along the way.

Change-Id: I449a7ec780bf061bdd325452f823673e2b39b6ae
2010-09-14 01:59:45 -07:00

336 lines
11 KiB
C++

/*
* 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/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