/*
* 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 _LIBINPUT_INPUT_TRANSPORT_H
#define _LIBINPUT_INPUT_TRANSPORT_H
/**
* Native input transport.
*
* The InputChannel provides a mechanism for exchanging InputMessage structures across processes.
*
* The InputPublisher and InputConsumer each handle one end-point of an input channel.
* The InputPublisher is used by the input dispatcher to send events to the application.
* The InputConsumer is used by the application to receive events from the input dispatcher.
*/
#include <input/Input.h>
#include <utils/Errors.h>
#include <utils/Timers.h>
#include <utils/RefBase.h>
#include <utils/String8.h>
#include <utils/Vector.h>
#include <utils/BitSet.h>
namespace android {
/*
* Intermediate representation used to send input events and related signals.
*
* Note that this structure is used for IPCs so its layout must be identical
* on 64 and 32 bit processes. This is tested in StructLayout_test.cpp.
*/
struct InputMessage {
enum {
TYPE_KEY = 1,
TYPE_MOTION = 2,
TYPE_FINISHED = 3,
};
struct Header {
uint32_t type;
// We don't need this field in order to align the body below but we
// leave it here because InputMessage::size() and other functions
// compute the size of this structure as sizeof(Header) + sizeof(Body).
uint32_t padding;
} header;
// Body *must* be 8 byte aligned.
union Body {
struct Key {
uint32_t seq;
nsecs_t eventTime __attribute__((aligned(8)));
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 __attribute__((aligned(8)));
inline size_t size() const {
return sizeof(Key);
}
} key;
struct Motion {
uint32_t seq;
nsecs_t eventTime __attribute__((aligned(8)));
int32_t deviceId;
int32_t source;
int32_t action;
int32_t actionButton;
int32_t flags;
int32_t metaState;
int32_t buttonState;
int32_t edgeFlags;
nsecs_t downTime __attribute__((aligned(8)));
float xOffset;
float yOffset;
float xPrecision;
float yPrecision;
uint32_t pointerCount;
// Note that PointerCoords requires 8 byte alignment.
struct Pointer {
PointerProperties properties;
PointerCoords coords;
} pointers[MAX_POINTERS];
int32_t getActionId() const {
uint32_t index = (action & AMOTION_EVENT_ACTION_POINTER_INDEX_MASK)
>> AMOTION_EVENT_ACTION_POINTER_INDEX_SHIFT;
return pointers[index].properties.id;
}
inline size_t size() const {
return sizeof(Motion) - sizeof(Pointer) * MAX_POINTERS
+ sizeof(Pointer) * pointerCount;
}
} motion;
struct Finished {
uint32_t seq;
bool handled;
inline size_t size() const {
return sizeof(Finished);
}
} finished;
} __attribute__((aligned(8))) body;
bool isValid(size_t actualSize) const;
size_t size() const;
};
/*
* An input channel consists of a local unix domain socket used to send and receive
* input messages across processes. Each channel has a descriptive name for debugging purposes.
*
* Each endpoint has its own InputChannel object that specifies its file descriptor.
*
* The input channel is closed when all references to it are released.
*/
class InputChannel : public RefBase {
protected:
virtual ~InputChannel();
public:
InputChannel(const String8& name, int fd);
/* Creates a pair of input channels.
*
* Returns OK on success.
*/
static status_t openInputChannelPair(const String8& name,
sp<InputChannel>& outServerChannel, sp<InputChannel>& outClientChannel);
inline String8 getName() const { return mName; }
inline int getFd() const { return mFd; }
/* Sends a message to the other endpoint.
*
* If the channel is full then the message is guaranteed not to have been sent at all.
* Try again after the consumer has sent a finished signal indicating that it has
* consumed some of the pending messages from the channel.
*
* Returns OK on success.
* Returns WOULD_BLOCK if the channel is full.
* Returns DEAD_OBJECT if the channel's peer has been closed.
* Other errors probably indicate that the channel is broken.
*/
status_t sendMessage(const InputMessage* msg);
/* Receives a message sent by the other endpoint.
*
* If there is no message present, try again after poll() indicates that the fd
* is readable.
*
* Returns OK on success.
* Returns WOULD_BLOCK if there is no message present.
* Returns DEAD_OBJECT if the channel's peer has been closed.
* Other errors probably indicate that the channel is broken.
*/
status_t receiveMessage(InputMessage* msg);
/* Returns a new object that has a duplicate of this channel's fd. */
sp<InputChannel> dup() const;
private:
String8 mName;
int mFd;
};
/*
* Publishes input events to an input channel.
*/
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; }
/* Publishes a key event to the input channel.
*
* Returns OK on success.
* Returns WOULD_BLOCK if the channel is full.
* Returns DEAD_OBJECT if the channel's peer has been closed.
* Returns BAD_VALUE if seq is 0.
* Other errors probably indicate that the channel is broken.
*/
status_t publishKeyEvent(
uint32_t seq,
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 input channel.
*
* Returns OK on success.
* Returns WOULD_BLOCK if the channel is full.
* Returns DEAD_OBJECT if the channel's peer has been closed.
* Returns BAD_VALUE if seq is 0 or if pointerCount is less than 1 or greater than MAX_POINTERS.
* Other errors probably indicate that the channel is broken.
*/
status_t publishMotionEvent(
uint32_t seq,
int32_t deviceId,
int32_t source,
int32_t action,
int32_t actionButton,
int32_t flags,
int32_t edgeFlags,
int32_t metaState,
int32_t buttonState,
float xOffset,
float yOffset,
float xPrecision,
float yPrecision,
nsecs_t downTime,
nsecs_t eventTime,
uint32_t pointerCount,
const PointerProperties* pointerProperties,
const PointerCoords* pointerCoords);
/* Receives the finished signal from the consumer in reply to the original dispatch signal.
* If a signal was received, returns the message sequence number,
* and whether the consumer handled the message.
*
* The returned sequence number is never 0 unless the operation failed.
*
* 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 receiveFinishedSignal(uint32_t* outSeq, bool* outHandled);
private:
sp<InputChannel> mChannel;
};
/*
* Consumes input events from an input channel.
*/
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; }
/* Consumes an input event from the input channel and copies its contents into
* an InputEvent object created using the specified factory.
*
* Tries to combine a series of move events into larger batches whenever possible.
*
* If consumeBatches is false, then defers consuming pending batched events if it
* is possible for additional samples to be added to them later. Call hasPendingBatch()
* to determine whether a pending batch is available to be consumed.
*
* If consumeBatches is true, then events are still batched but they are consumed
* immediately as soon as the input channel is exhausted.
*
* The frameTime parameter specifies the time when the current display frame started
* rendering in the CLOCK_MONOTONIC time base, or -1 if unknown.
*
* The returned sequence number is never 0 unless the operation failed.
*
* Returns OK on success.
* Returns WOULD_BLOCK if there is no event present.
* Returns DEAD_OBJECT if the channel's peer has been closed.
* Returns NO_MEMORY if the event could not be created.
* Other errors probably indicate that the channel is broken.
*/
status_t consume(InputEventFactoryInterface* factory, bool consumeBatches,
nsecs_t frameTime, uint32_t* outSeq, InputEvent** outEvent);
/* Sends a finished signal to the publisher to inform it that the message
* with the specified sequence number has finished being process and whether
* the message was handled by the consumer.
*
* Returns OK on success.
* Returns BAD_VALUE if seq is 0.
* Other errors probably indicate that the channel is broken.
*/
status_t sendFinishedSignal(uint32_t seq, bool handled);
/* Returns true if there is a deferred event waiting.
*
* Should be called after calling consume() to determine whether the consumer
* has a deferred event to be processed. Deferred events are somewhat special in
* that they have already been removed from the input channel. If the input channel
* becomes empty, the client may need to do extra work to ensure that it processes
* the deferred event despite the fact that the input channel's file descriptor
* is not readable.
*
* One option is simply to call consume() in a loop until it returns WOULD_BLOCK.
* This guarantees that all deferred events will be processed.
*
* Alternately, the caller can call hasDeferredEvent() to determine whether there is
* a deferred event waiting and then ensure that its event loop wakes up at least
* one more time to consume the deferred event.
*/
bool hasDeferredEvent() const;
/* Returns true if there is a pending batch.
*
* Should be called after calling consume() with consumeBatches == false to determine
* whether consume() should be called again later on with consumeBatches == true.
*/
bool hasPendingBatch() const;
private:
// True if touch resampling is enabled.
const bool mResampleTouch;
// The input channel.
sp<InputChannel> mChannel;
// The current input message.
InputMessage mMsg;
// True if mMsg contains a valid input message that was deferred from the previous
// call to consume and that still needs to be handled.
bool mMsgDeferred;
// Batched motion events per device and source.
struct Batch {
Vector<InputMessage> samples;
};
Vector<Batch> mBatches;
// Touch state per device and source, only for sources of class pointer.
struct History {
nsecs_t eventTime;
BitSet32 idBits;
int32_t idToIndex[MAX_POINTER_ID + 1];
PointerCoords pointers[MAX_POINTERS];
void initializeFrom(const InputMessage* msg) {
eventTime = msg->body.motion.eventTime;
idBits.clear();
for (uint32_t i = 0; i < msg->body.motion.pointerCount; i++) {
uint32_t id = msg->body.motion.pointers[i].properties.id;
idBits.markBit(id);
idToIndex[id] = i;
pointers[i].copyFrom(msg->body.motion.pointers[i].coords);
}
}
const PointerCoords& getPointerById(uint32_t id) const {
return pointers[idToIndex[id]];
}
};
struct TouchState {
int32_t deviceId;
int32_t source;
size_t historyCurrent;
size_t historySize;
History history[2];
History lastResample;
void initialize(int32_t deviceId, int32_t source) {
this->deviceId = deviceId;
this->source = source;
historyCurrent = 0;
historySize = 0;
lastResample.eventTime = 0;
lastResample.idBits.clear();
}
void addHistory(const InputMessage* msg) {
historyCurrent ^= 1;
if (historySize < 2) {
historySize += 1;
}
history[historyCurrent].initializeFrom(msg);
}
const History* getHistory(size_t index) const {
return &history[(historyCurrent + index) & 1];
}
};
Vector<TouchState> mTouchStates;
// Chain of batched sequence numbers. When multiple input messages are combined into
// a batch, we append a record here that associates the last sequence number in the
// batch with the previous one. When the finished signal is sent, we traverse the
// chain to individually finish all input messages that were part of the batch.
struct SeqChain {
uint32_t seq; // sequence number of batched input message
uint32_t chain; // sequence number of previous batched input message
};
Vector<SeqChain> mSeqChains;
status_t consumeBatch(InputEventFactoryInterface* factory,
nsecs_t frameTime, uint32_t* outSeq, InputEvent** outEvent);
status_t consumeSamples(InputEventFactoryInterface* factory,
Batch& batch, size_t count, uint32_t* outSeq, InputEvent** outEvent);
void updateTouchState(InputMessage* msg);
void rewriteMessage(const TouchState& state, InputMessage* msg);
void resampleTouchState(nsecs_t frameTime, MotionEvent* event,
const InputMessage *next);
ssize_t findBatch(int32_t deviceId, int32_t source) const;
ssize_t findTouchState(int32_t deviceId, int32_t source) const;
status_t sendUnchainedFinishedSignal(uint32_t seq, bool handled);
static void initializeKeyEvent(KeyEvent* event, const InputMessage* msg);
static void initializeMotionEvent(MotionEvent* event, const InputMessage* msg);
static void addSample(MotionEvent* event, const InputMessage* msg);
static bool canAddSample(const Batch& batch, const InputMessage* msg);
static ssize_t findSampleNoLaterThan(const Batch& batch, nsecs_t time);
static bool shouldResampleTool(int32_t toolType);
static bool isTouchResamplingEnabled();
};
} // namespace android
#endif // _LIBINPUT_INPUT_TRANSPORT_H