text: //
  // Copyright 2010 The Android Open Source Project
  //
  // Provides a shared memory transport for input events.
  //
  #define LOG_TAG "InputTransport"
  
  //#define LOG_NDEBUG 0
  
  // Log debug messages about channel messages (send message, receive message)
  #define DEBUG_CHANNEL_MESSAGES 0
  
  // Log debug messages whenever InputChannel objects are created/destroyed
  #define DEBUG_CHANNEL_LIFECYCLE 0
  
  // Log debug messages about transport actions
  #define DEBUG_TRANSPORT_ACTIONS 0
  
  // Log debug messages about touch event resampling
  #define DEBUG_RESAMPLING 0
  
  
  #include <errno.h>
  #include <fcntl.h>
  #include <inttypes.h>
  #include <math.h>
  #include <sys/types.h>
  #include <sys/socket.h>
  #include <unistd.h>
  
  #include <cutils/log.h>
  #include <cutils/properties.h>
  #include <input/InputTransport.h>
  
  
  namespace android {
  
  // Socket buffer size.  The default is typically about 128KB, which is much larger than
  // we really need.  So we make it smaller.  It just needs to be big enough to hold
  // a few dozen large multi-finger motion events in the case where an application gets
  // behind processing touches.
  static const size_t SOCKET_BUFFER_SIZE = 32 * 1024;
  
  // Nanoseconds per milliseconds.
  static const nsecs_t NANOS_PER_MS = 1000000;
  
  // Latency added during resampling.  A few milliseconds doesn't hurt much but
  // reduces the impact of mispredicted touch positions.
  static const nsecs_t RESAMPLE_LATENCY = 5 * NANOS_PER_MS;
  
  // Minimum time difference between consecutive samples before attempting to resample.
  static const nsecs_t RESAMPLE_MIN_DELTA = 2 * NANOS_PER_MS;
  
  // Maximum time difference between consecutive samples before attempting to resample
  // by extrapolation.
  static const nsecs_t RESAMPLE_MAX_DELTA = 20 * NANOS_PER_MS;
  
  // Maximum time to predict forward from the last known state, to avoid predicting too
  // far into the future.  This time is further bounded by 50% of the last time delta.
  static const nsecs_t RESAMPLE_MAX_PREDICTION = 8 * NANOS_PER_MS;
  
  template<typename T>
  inline static T min(const T& a, const T& b) {
      return a < b ? a : b;
  }
  
  inline static float lerp(float a, float b, float alpha) {
      return a + alpha * (b - a);
  }
  
  // --- InputMessage ---
  
  bool InputMessage::isValid(size_t actualSize) const {
      if (size() == actualSize) {
          switch (header.type) {
          case TYPE_KEY:
              return true;
          case TYPE_MOTION:
              return body.motion.pointerCount > 0
                      && body.motion.pointerCount <= MAX_POINTERS;
          case TYPE_FINISHED:
              return true;
          }
      }
      return false;
  }
  
  size_t InputMessage::size() const {
      switch (header.type) {
      case TYPE_KEY:
          return sizeof(Header) + body.key.size();
      case TYPE_MOTION:
          return sizeof(Header) + body.motion.size();
      case TYPE_FINISHED:
          return sizeof(Header) + body.finished.size();
      }
      return sizeof(Header);
  }
  
  
  // --- InputChannel ---
  
  InputChannel::InputChannel(const String8& name, int fd) :
          mName(name), mFd(fd) {
  #if DEBUG_CHANNEL_LIFECYCLE
      ALOGD("Input channel constructed: name='%s', fd=%d",
              mName.string(), fd);
  #endif
  
      int result = fcntl(mFd, F_SETFL, O_NONBLOCK);
      LOG_ALWAYS_FATAL_IF(result != 0, "channel '%s' ~ Could not make socket "
              "non-blocking.  errno=%d", mName.string(), errno);
  }
  
  InputChannel::~InputChannel() {
  #if DEBUG_CHANNEL_LIFECYCLE
      ALOGD("Input channel destroyed: name='%s', fd=%d",
              mName.string(), mFd);
  #endif
  
      ::close(mFd);
  }
  
  status_t InputChannel::openInputChannelPair(const String8& name,
          sp<InputChannel>& outServerChannel, sp<InputChannel>& outClientChannel) {
      int sockets[2];
      if (socketpair(AF_UNIX, SOCK_SEQPACKET, 0, sockets)) {
          status_t result = -errno;
          ALOGE("channel '%s' ~ Could not create socket pair.  errno=%d",
                  name.string(), errno);
          outServerChannel.clear();
          outClientChannel.clear();
          return result;
      }
  
      int bufferSize = SOCKET_BUFFER_SIZE;
      setsockopt(sockets[0], SOL_SOCKET, SO_SNDBUF, &bufferSize, sizeof(bufferSize));
      setsockopt(sockets[0], SOL_SOCKET, SO_RCVBUF, &bufferSize, sizeof(bufferSize));
      setsockopt(sockets[1], SOL_SOCKET, SO_SNDBUF, &bufferSize, sizeof(bufferSize));
      setsockopt(sockets[1], SOL_SOCKET, SO_RCVBUF, &bufferSize, sizeof(bufferSize));
  
      String8 serverChannelName = name;
      serverChannelName.append(" (server)");
      outServerChannel = new InputChannel(serverChannelName, sockets[0]);
  
      String8 clientChannelName = name;
      clientChannelName.append(" (client)");
      outClientChannel = new InputChannel(clientChannelName, sockets[1]);
      return OK;
  }
  
  status_t InputChannel::sendMessage(const InputMessage* msg) {
      size_t msgLength = msg->size();
      ssize_t nWrite;
      do {
          nWrite = ::send(mFd, msg, msgLength, MSG_DONTWAIT | MSG_NOSIGNAL);
      } while (nWrite == -1 && errno == EINTR);
  
      if (nWrite < 0) {
          int error = errno;
  #if DEBUG_CHANNEL_MESSAGES
          ALOGD("channel '%s' ~ error sending message of type %d, errno=%d", mName.string(),
                  msg->header.type, error);
  #endif
          if (error == EAGAIN || error == EWOULDBLOCK) {
              return WOULD_BLOCK;
          }
          if (error == EPIPE || error == ENOTCONN || error == ECONNREFUSED || error == ECONNRESET) {
              return DEAD_OBJECT;
          }
          return -error;
      }
  
      if (size_t(nWrite) != msgLength) {
  #if DEBUG_CHANNEL_MESSAGES
          ALOGD("channel '%s' ~ error sending message type %d, send was incomplete",
                  mName.string(), msg->header.type);
  #endif
          return DEAD_OBJECT;
      }
  
  #if DEBUG_CHANNEL_MESSAGES
      ALOGD("channel '%s' ~ sent message of type %d", mName.string(), msg->header.type);
  #endif
      return OK;
  }
  
  status_t InputChannel::receiveMessage(InputMessage* msg) {
      ssize_t nRead;
      do {
          nRead = ::recv(mFd, msg, sizeof(InputMessage), MSG_DONTWAIT);
      } while (nRead == -1 && errno == EINTR);
  
      if (nRead < 0) {
          int error = errno;
  #if DEBUG_CHANNEL_MESSAGES
          ALOGD("channel '%s' ~ receive message failed, errno=%d", mName.string(), errno);
  #endif
          if (error == EAGAIN || error == EWOULDBLOCK) {
              return WOULD_BLOCK;
          }
          if (error == EPIPE || error == ENOTCONN || error == ECONNREFUSED) {
              return DEAD_OBJECT;
          }
          return -error;
      }
  
      if (nRead == 0) { // check for EOF
  #if DEBUG_CHANNEL_MESSAGES
          ALOGD("channel '%s' ~ receive message failed because peer was closed", mName.string());
  #endif
          return DEAD_OBJECT;
      }
  
      if (!msg->isValid(nRead)) {
  #if DEBUG_CHANNEL_MESSAGES
          ALOGD("channel '%s' ~ received invalid message", mName.string());
  #endif
          return BAD_VALUE;
      }
  
  #if DEBUG_CHANNEL_MESSAGES
      ALOGD("channel '%s' ~ received message of type %d", mName.string(), msg->header.type);
  #endif
      return OK;
  }
  
  sp<InputChannel> InputChannel::dup() const {
      int fd = ::dup(getFd());
      return fd >= 0 ? new InputChannel(getName(), fd) : NULL;
  }
  
  
  // --- InputPublisher ---
  
  InputPublisher::InputPublisher(const sp<InputChannel>& channel) :
          mChannel(channel) {
  }
  
  InputPublisher::~InputPublisher() {
  }
  
  status_t InputPublisher::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) {
  #if DEBUG_TRANSPORT_ACTIONS
      ALOGD("channel '%s' publisher ~ publishKeyEvent: seq=%u, deviceId=%d, source=0x%x, "
              "action=0x%x, flags=0x%x, keyCode=%d, scanCode=%d, metaState=0x%x, repeatCount=%d,"
              "downTime=%lld, eventTime=%lld",
              mChannel->getName().string(), seq,
              deviceId, source, action, flags, keyCode, scanCode, metaState, repeatCount,
              downTime, eventTime);
  #endif
  
      if (!seq) {
          ALOGE("Attempted to publish a key event with sequence number 0.");
          return BAD_VALUE;
      }
  
      InputMessage msg;
      msg.header.type = InputMessage::TYPE_KEY;
      msg.body.key.seq = seq;
      msg.body.key.deviceId = deviceId;
      msg.body.key.source = source;
      msg.body.key.action = action;
      msg.body.key.flags = flags;
      msg.body.key.keyCode = keyCode;
      msg.body.key.scanCode = scanCode;
      msg.body.key.metaState = metaState;
      msg.body.key.repeatCount = repeatCount;
      msg.body.key.downTime = downTime;
      msg.body.key.eventTime = eventTime;
      return mChannel->sendMessage(&msg);
  }
  
  status_t InputPublisher::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) {
  #if DEBUG_TRANSPORT_ACTIONS
      ALOGD("channel '%s' publisher ~ publishMotionEvent: seq=%u, deviceId=%d, source=0x%x, "
              "action=0x%x, actionButton=0x%08x, flags=0x%x, edgeFlags=0x%x, "
              "metaState=0x%x, buttonState=0x%x, xOffset=%f, yOffset=%f, "
              "xPrecision=%f, yPrecision=%f, downTime=%lld, eventTime=%lld, "
              "pointerCount=%" PRIu32,
              mChannel->getName().string(), seq,
              deviceId, source, action, actionButton, flags, edgeFlags, metaState, buttonState,
              xOffset, yOffset, xPrecision, yPrecision, downTime, eventTime, pointerCount);
  #endif
  
      if (!seq) {
          ALOGE("Attempted to publish a motion event with sequence number 0.");
          return BAD_VALUE;
      }
  
      if (pointerCount > MAX_POINTERS || pointerCount < 1) {
          ALOGE("channel '%s' publisher ~ Invalid number of pointers provided: %" PRIu32 ".",
                  mChannel->getName().string(), pointerCount);
          return BAD_VALUE;
      }
  
      InputMessage msg;
      msg.header.type = InputMessage::TYPE_MOTION;
      msg.body.motion.seq = seq;
      msg.body.motion.deviceId = deviceId;
      msg.body.motion.source = source;
      msg.body.motion.action = action;
      msg.body.motion.actionButton = actionButton;
      msg.body.motion.flags = flags;
      msg.body.motion.edgeFlags = edgeFlags;
      msg.body.motion.metaState = metaState;
      msg.body.motion.buttonState = buttonState;
      msg.body.motion.xOffset = xOffset;
      msg.body.motion.yOffset = yOffset;
      msg.body.motion.xPrecision = xPrecision;
      msg.body.motion.yPrecision = yPrecision;
      msg.body.motion.downTime = downTime;
      msg.body.motion.eventTime = eventTime;
      msg.body.motion.pointerCount = pointerCount;
      for (uint32_t i = 0; i < pointerCount; i++) {
          msg.body.motion.pointers[i].properties.copyFrom(pointerProperties[i]);
          msg.body.motion.pointers[i].coords.copyFrom(pointerCoords[i]);
      }
      return mChannel->sendMessage(&msg);
  }
  
  status_t InputPublisher::receiveFinishedSignal(uint32_t* outSeq, bool* outHandled) {
  #if DEBUG_TRANSPORT_ACTIONS
      ALOGD("channel '%s' publisher ~ receiveFinishedSignal",
              mChannel->getName().string());
  #endif
  
      InputMessage msg;
      status_t result = mChannel->receiveMessage(&msg);
      if (result) {
          *outSeq = 0;
          *outHandled = false;
          return result;
      }
      if (msg.header.type != InputMessage::TYPE_FINISHED) {
          ALOGE("channel '%s' publisher ~ Received unexpected message of type %d from consumer",
                  mChannel->getName().string(), msg.header.type);
          return UNKNOWN_ERROR;
      }
      *outSeq = msg.body.finished.seq;
      *outHandled = msg.body.finished.handled;
      return OK;
  }
  
  // --- InputConsumer ---
  
  InputConsumer::InputConsumer(const sp<InputChannel>& channel) :
          mResampleTouch(isTouchResamplingEnabled()),
          mChannel(channel), mMsgDeferred(false) {
  }
  
  InputConsumer::~InputConsumer() {
  }
  
  bool InputConsumer::isTouchResamplingEnabled() {
      char value[PROPERTY_VALUE_MAX];
      int length = property_get("ro.input.noresample", value, NULL);
      if (length > 0) {
          if (!strcmp("1", value)) {
              return false;
          }
          if (strcmp("0", value)) {
              ALOGD("Unrecognized property value for 'ro.input.noresample'.  "
                      "Use '1' or '0'.");
          }
      }
      return true;
  }
  
  status_t InputConsumer::consume(InputEventFactoryInterface* factory,
          bool consumeBatches, nsecs_t frameTime, uint32_t* outSeq, InputEvent** outEvent) {
  #if DEBUG_TRANSPORT_ACTIONS
      ALOGD("channel '%s' consumer ~ consume: consumeBatches=%s, frameTime=%lld",
              mChannel->getName().string(), consumeBatches ? "true" : "false", frameTime);
  #endif
  
      *outSeq = 0;
      *outEvent = NULL;
  
      // Fetch the next input message.
      // Loop until an event can be returned or no additional events are received.
      while (!*outEvent) {
          if (mMsgDeferred) {
              // mMsg contains a valid input message from the previous call to consume
              // that has not yet been processed.
              mMsgDeferred = false;
          } else {
              // Receive a fresh message.
              status_t result = mChannel->receiveMessage(&mMsg);
              if (result) {
                  // Consume the next batched event unless batches are being held for later.
                  if (consumeBatches || result != WOULD_BLOCK) {
                      result = consumeBatch(factory, frameTime, outSeq, outEvent);
                      if (*outEvent) {
  #if DEBUG_TRANSPORT_ACTIONS
                          ALOGD("channel '%s' consumer ~ consumed batch event, seq=%u",
                                  mChannel->getName().string(), *outSeq);
  #endif
                          break;
                      }
                  }
                  return result;
              }
          }
  
          switch (mMsg.header.type) {
          case InputMessage::TYPE_KEY: {
              KeyEvent* keyEvent = factory->createKeyEvent();
              if (!keyEvent) return NO_MEMORY;
  
              initializeKeyEvent(keyEvent, &mMsg);
              *outSeq = mMsg.body.key.seq;
              *outEvent = keyEvent;
  #if DEBUG_TRANSPORT_ACTIONS
              ALOGD("channel '%s' consumer ~ consumed key event, seq=%u",
                      mChannel->getName().string(), *outSeq);
  #endif
              break;
          }
  
          case AINPUT_EVENT_TYPE_MOTION: {
              ssize_t batchIndex = findBatch(mMsg.body.motion.deviceId, mMsg.body.motion.source);
              if (batchIndex >= 0) {
                  Batch& batch = mBatches.editItemAt(batchIndex);
                  if (canAddSample(batch, &mMsg)) {
                      batch.samples.push(mMsg);
  #if DEBUG_TRANSPORT_ACTIONS
                      ALOGD("channel '%s' consumer ~ appended to batch event",
                              mChannel->getName().string());
  #endif
                      break;
                  } else {
                      // We cannot append to the batch in progress, so we need to consume
                      // the previous batch right now and defer the new message until later.
                      mMsgDeferred = true;
                      status_t result = consumeSamples(factory,
                              batch, batch.samples.size(), outSeq, outEvent);
                      mBatches.removeAt(batchIndex);
                      if (result) {
                          return result;
                      }
  #if DEBUG_TRANSPORT_ACTIONS
                      ALOGD("channel '%s' consumer ~ consumed batch event and "
                              "deferred current event, seq=%u",
                              mChannel->getName().string(), *outSeq);
  #endif
                      break;
                  }
              }
  
              // Start a new batch if needed.
              if (mMsg.body.motion.action == AMOTION_EVENT_ACTION_MOVE
                      || mMsg.body.motion.action == AMOTION_EVENT_ACTION_HOVER_MOVE) {
                  mBatches.push();
                  Batch& batch = mBatches.editTop();
                  batch.samples.push(mMsg);
  #if DEBUG_TRANSPORT_ACTIONS
                  ALOGD("channel '%s' consumer ~ started batch event",
                          mChannel->getName().string());
  #endif
                  break;
              }
  
              MotionEvent* motionEvent = factory->createMotionEvent();
              if (! motionEvent) return NO_MEMORY;
  
              updateTouchState(&mMsg);
              initializeMotionEvent(motionEvent, &mMsg);
              *outSeq = mMsg.body.motion.seq;
              *outEvent = motionEvent;
  #if DEBUG_TRANSPORT_ACTIONS
              ALOGD("channel '%s' consumer ~ consumed motion event, seq=%u",
                      mChannel->getName().string(), *outSeq);
  #endif
              break;
          }
  
          default:
              ALOGE("channel '%s' consumer ~ Received unexpected message of type %d",
                      mChannel->getName().string(), mMsg.header.type);
              return UNKNOWN_ERROR;
          }
      }
      return OK;
  }
  
  status_t InputConsumer::consumeBatch(InputEventFactoryInterface* factory,
          nsecs_t frameTime, uint32_t* outSeq, InputEvent** outEvent) {
      status_t result;
      for (size_t i = mBatches.size(); i > 0; ) {
          i--;
          Batch& batch = mBatches.editItemAt(i);
          if (frameTime < 0) {
              result = consumeSamples(factory, batch, batch.samples.size(),
                      outSeq, outEvent);
              mBatches.removeAt(i);
              return result;
          }
  
          nsecs_t sampleTime = frameTime;
          if (mResampleTouch) {
              sampleTime -= RESAMPLE_LATENCY;
          }
          ssize_t split = findSampleNoLaterThan(batch, sampleTime);
          if (split < 0) {
              continue;
          }
  
          result = consumeSamples(factory, batch, split + 1, outSeq, outEvent);
          const InputMessage* next;
          if (batch.samples.isEmpty()) {
              mBatches.removeAt(i);
              next = NULL;
          } else {
              next = &batch.samples.itemAt(0);
          }
          if (!result && mResampleTouch) {
              resampleTouchState(sampleTime, static_cast<MotionEvent*>(*outEvent), next);
          }
          return result;
      }
  
      return WOULD_BLOCK;
  }
  
  status_t InputConsumer::consumeSamples(InputEventFactoryInterface* factory,
          Batch& batch, size_t count, uint32_t* outSeq, InputEvent** outEvent) {
      MotionEvent* motionEvent = factory->createMotionEvent();
      if (! motionEvent) return NO_MEMORY;
  
      uint32_t chain = 0;
      for (size_t i = 0; i < count; i++) {
          InputMessage& msg = batch.samples.editItemAt(i);
          updateTouchState(&msg);
          if (i) {
              SeqChain seqChain;
              seqChain.seq = msg.body.motion.seq;
              seqChain.chain = chain;
              mSeqChains.push(seqChain);
              addSample(motionEvent, &msg);
          } else {
              initializeMotionEvent(motionEvent, &msg);
          }
          chain = msg.body.motion.seq;
      }
      batch.samples.removeItemsAt(0, count);
  
      *outSeq = chain;
      *outEvent = motionEvent;
      return OK;
  }
  
  void InputConsumer::updateTouchState(InputMessage* msg) {
      if (!mResampleTouch ||
              !(msg->body.motion.source & AINPUT_SOURCE_CLASS_POINTER)) {
          return;
      }
  
      int32_t deviceId = msg->body.motion.deviceId;
      int32_t source = msg->body.motion.source;
      nsecs_t eventTime = msg->body.motion.eventTime;
  
      // Update the touch state history to incorporate the new input message.
      // If the message is in the past relative to the most recently produced resampled
      // touch, then use the resampled time and coordinates instead.
      switch (msg->body.motion.action & AMOTION_EVENT_ACTION_MASK) {
      case AMOTION_EVENT_ACTION_DOWN: {
          ssize_t index = findTouchState(deviceId, source);
          if (index < 0) {
              mTouchStates.push();
              index = mTouchStates.size() - 1;
          }
          TouchState& touchState = mTouchStates.editItemAt(index);
          touchState.initialize(deviceId, source);
          touchState.addHistory(msg);
          break;
      }
  
      case AMOTION_EVENT_ACTION_MOVE: {
          ssize_t index = findTouchState(deviceId, source);
          if (index >= 0) {
              TouchState& touchState = mTouchStates.editItemAt(index);
              touchState.addHistory(msg);
              if (eventTime < touchState.lastResample.eventTime) {
                  rewriteMessage(touchState, msg);
              } else {
                  touchState.lastResample.idBits.clear();
              }
          }
          break;
      }
  
      case AMOTION_EVENT_ACTION_POINTER_DOWN: {
          ssize_t index = findTouchState(deviceId, source);
          if (index >= 0) {
              TouchState& touchState = mTouchStates.editItemAt(index);
              touchState.lastResample.idBits.clearBit(msg->body.motion.getActionId());
              rewriteMessage(touchState, msg);
          }
          break;
      }
  
      case AMOTION_EVENT_ACTION_POINTER_UP: {
          ssize_t index = findTouchState(deviceId, source);
          if (index >= 0) {
              TouchState& touchState = mTouchStates.editItemAt(index);
              rewriteMessage(touchState, msg);
              touchState.lastResample.idBits.clearBit(msg->body.motion.getActionId());
          }
          break;
      }
  
      case AMOTION_EVENT_ACTION_SCROLL: {
          ssize_t index = findTouchState(deviceId, source);
          if (index >= 0) {
              const TouchState& touchState = mTouchStates.itemAt(index);
              rewriteMessage(touchState, msg);
          }
          break;
      }
  
      case AMOTION_EVENT_ACTION_UP:
      case AMOTION_EVENT_ACTION_CANCEL: {
          ssize_t index = findTouchState(deviceId, source);
          if (index >= 0) {
              const TouchState& touchState = mTouchStates.itemAt(index);
              rewriteMessage(touchState, msg);
              mTouchStates.removeAt(index);
          }
          break;
      }
      }
  }
  
  void InputConsumer::rewriteMessage(const TouchState& state, InputMessage* msg) {
      for (uint32_t i = 0; i < msg->body.motion.pointerCount; i++) {
          uint32_t id = msg->body.motion.pointers[i].properties.id;
          if (state.lastResample.idBits.hasBit(id)) {
              PointerCoords& msgCoords = msg->body.motion.pointers[i].coords;
              const PointerCoords& resampleCoords = state.lastResample.getPointerById(id);
  #if DEBUG_RESAMPLING
              ALOGD("[%d] - rewrite (%0.3f, %0.3f), old (%0.3f, %0.3f)", id,
                      resampleCoords.getAxisValue(AMOTION_EVENT_AXIS_X),
                      resampleCoords.getAxisValue(AMOTION_EVENT_AXIS_Y),
                      msgCoords.getAxisValue(AMOTION_EVENT_AXIS_X),
                      msgCoords.getAxisValue(AMOTION_EVENT_AXIS_Y));
  #endif
              msgCoords.setAxisValue(AMOTION_EVENT_AXIS_X, resampleCoords.getX());
              msgCoords.setAxisValue(AMOTION_EVENT_AXIS_Y, resampleCoords.getY());
          }
      }
  }
  
  void InputConsumer::resampleTouchState(nsecs_t sampleTime, MotionEvent* event,
      const InputMessage* next) {
      if (!mResampleTouch
              || !(event->getSource() & AINPUT_SOURCE_CLASS_POINTER)
              || event->getAction() != AMOTION_EVENT_ACTION_MOVE) {
          return;
      }
  
      ssize_t index = findTouchState(event->getDeviceId(), event->getSource());
      if (index < 0) {
  #if DEBUG_RESAMPLING
          ALOGD("Not resampled, no touch state for device.");
  #endif
          return;
      }
  
      TouchState& touchState = mTouchStates.editItemAt(index);
      if (touchState.historySize < 1) {
  #if DEBUG_RESAMPLING
          ALOGD("Not resampled, no history for device.");
  #endif
          return;
      }
  
      // Ensure that the current sample has all of the pointers that need to be reported.
      const History* current = touchState.getHistory(0);
      size_t pointerCount = event->getPointerCount();
      for (size_t i = 0; i < pointerCount; i++) {
          uint32_t id = event->getPointerId(i);
          if (!current->idBits.hasBit(id)) {
  #if DEBUG_RESAMPLING
              ALOGD("Not resampled, missing id %d", id);
  #endif
              return;
          }
      }
  
      // Find the data to use for resampling.
      const History* other;
      History future;
      float alpha;
      if (next) {
          // Interpolate between current sample and future sample.
          // So current->eventTime <= sampleTime <= future.eventTime.
          future.initializeFrom(next);
          other = &future;
          nsecs_t delta = future.eventTime - current->eventTime;
          if (delta < RESAMPLE_MIN_DELTA) {
  #if DEBUG_RESAMPLING
              ALOGD("Not resampled, delta time is too small: %lld ns.", delta);
  #endif
              return;
          }
          alpha = float(sampleTime - current->eventTime) / delta;
      } else if (touchState.historySize >= 2) {
          // Extrapolate future sample using current sample and past sample.
          // So other->eventTime <= current->eventTime <= sampleTime.
          other = touchState.getHistory(1);
          nsecs_t delta = current->eventTime - other->eventTime;
          if (delta < RESAMPLE_MIN_DELTA) {
  #if DEBUG_RESAMPLING
              ALOGD("Not resampled, delta time is too small: %lld ns.", delta);
  #endif
              return;
          } else if (delta > RESAMPLE_MAX_DELTA) {
  #if DEBUG_RESAMPLING
              ALOGD("Not resampled, delta time is too large: %lld ns.", delta);
  #endif
              return;
          }
          nsecs_t maxPredict = current->eventTime + min(delta / 2, RESAMPLE_MAX_PREDICTION);
          if (sampleTime > maxPredict) {
  #if DEBUG_RESAMPLING
              ALOGD("Sample time is too far in the future, adjusting prediction "
                      "from %lld to %lld ns.",
                      sampleTime - current->eventTime, maxPredict - current->eventTime);
  #endif
              sampleTime = maxPredict;
          }
          alpha = float(current->eventTime - sampleTime) / delta;
      } else {
  #if DEBUG_RESAMPLING
          ALOGD("Not resampled, insufficient data.");
  #endif
          return;
      }
  
      // Resample touch coordinates.
      touchState.lastResample.eventTime = sampleTime;
      touchState.lastResample.idBits.clear();
      for (size_t i = 0; i < pointerCount; i++) {
          uint32_t id = event->getPointerId(i);
          touchState.lastResample.idToIndex[id] = i;
          touchState.lastResample.idBits.markBit(id);
          PointerCoords& resampledCoords = touchState.lastResample.pointers[i];
          const PointerCoords& currentCoords = current->getPointerById(id);
          if (other->idBits.hasBit(id)
                  && shouldResampleTool(event->getToolType(i))) {
              const PointerCoords& otherCoords = other->getPointerById(id);
              resampledCoords.copyFrom(currentCoords);
              resampledCoords.setAxisValue(AMOTION_EVENT_AXIS_X,
                      lerp(currentCoords.getX(), otherCoords.getX(), alpha));
              resampledCoords.setAxisValue(AMOTION_EVENT_AXIS_Y,
                      lerp(currentCoords.getY(), otherCoords.getY(), alpha));
  #if DEBUG_RESAMPLING
              ALOGD("[%d] - out (%0.3f, %0.3f), cur (%0.3f, %0.3f), "
                      "other (%0.3f, %0.3f), alpha %0.3f",
                      id, resampledCoords.getX(), resampledCoords.getY(),
                      currentCoords.getX(), currentCoords.getY(),
                      otherCoords.getX(), otherCoords.getY(),
                      alpha);
  #endif
          } else {
              resampledCoords.copyFrom(currentCoords);
  #if DEBUG_RESAMPLING
              ALOGD("[%d] - out (%0.3f, %0.3f), cur (%0.3f, %0.3f)",
                      id, resampledCoords.getX(), resampledCoords.getY(),
                      currentCoords.getX(), currentCoords.getY());
  #endif
          }
      }
  
      event->addSample(sampleTime, touchState.lastResample.pointers);
  }
  
  bool InputConsumer::shouldResampleTool(int32_t toolType) {
      return toolType == AMOTION_EVENT_TOOL_TYPE_FINGER
              || toolType == AMOTION_EVENT_TOOL_TYPE_UNKNOWN;
  }
  
  status_t InputConsumer::sendFinishedSignal(uint32_t seq, bool handled) {
  #if DEBUG_TRANSPORT_ACTIONS
      ALOGD("channel '%s' consumer ~ sendFinishedSignal: seq=%u, handled=%s",
              mChannel->getName().string(), seq, handled ? "true" : "false");
  #endif
  
      if (!seq) {
          ALOGE("Attempted to send a finished signal with sequence number 0.");
          return BAD_VALUE;
      }
  
      // Send finished signals for the batch sequence chain first.
      size_t seqChainCount = mSeqChains.size();
      if (seqChainCount) {
          uint32_t currentSeq = seq;
          uint32_t chainSeqs[seqChainCount];
          size_t chainIndex = 0;
          for (size_t i = seqChainCount; i > 0; ) {
               i--;
               const SeqChain& seqChain = mSeqChains.itemAt(i);
               if (seqChain.seq == currentSeq) {
                   currentSeq = seqChain.chain;
                   chainSeqs[chainIndex++] = currentSeq;
                   mSeqChains.removeAt(i);
               }
          }
          status_t status = OK;
          while (!status && chainIndex > 0) {
              chainIndex--;
              status = sendUnchainedFinishedSignal(chainSeqs[chainIndex], handled);
          }
          if (status) {
              // An error occurred so at least one signal was not sent, reconstruct the chain.
              do {
                  SeqChain seqChain;
                  seqChain.seq = chainIndex != 0 ? chainSeqs[chainIndex - 1] : seq;
                  seqChain.chain = chainSeqs[chainIndex];
                  mSeqChains.push(seqChain);
                  if (chainIndex != 0) {
                      chainIndex--;
                  }
              } while (chainIndex > 0);
              return status;
          }
      }
  
      // Send finished signal for the last message in the batch.
      return sendUnchainedFinishedSignal(seq, handled);
  }
  
  status_t InputConsumer::sendUnchainedFinishedSignal(uint32_t seq, bool handled) {
      InputMessage msg;
      msg.header.type = InputMessage::TYPE_FINISHED;
      msg.body.finished.seq = seq;
      msg.body.finished.handled = handled;
      return mChannel->sendMessage(&msg);
  }
  
  bool InputConsumer::hasDeferredEvent() const {
      return mMsgDeferred;
  }
  
  bool InputConsumer::hasPendingBatch() const {
      return !mBatches.isEmpty();
  }
  
  ssize_t InputConsumer::findBatch(int32_t deviceId, int32_t source) const {
      for (size_t i = 0; i < mBatches.size(); i++) {
          const Batch& batch = mBatches.itemAt(i);
          const InputMessage& head = batch.samples.itemAt(0);
          if (head.body.motion.deviceId == deviceId && head.body.motion.source == source) {
              return i;
          }
      }
      return -1;
  }
  
  ssize_t InputConsumer::findTouchState(int32_t deviceId, int32_t source) const {
      for (size_t i = 0; i < mTouchStates.size(); i++) {
          const TouchState& touchState = mTouchStates.itemAt(i);
          if (touchState.deviceId == deviceId && touchState.source == source) {
              return i;
          }
      }
      return -1;
  }
  
  void InputConsumer::initializeKeyEvent(KeyEvent* event, const InputMessage* msg) {
      event->initialize(
              msg->body.key.deviceId,
              msg->body.key.source,
              msg->body.key.action,
              msg->body.key.flags,
              msg->body.key.keyCode,
              msg->body.key.scanCode,
              msg->body.key.metaState,
              msg->body.key.repeatCount,
              msg->body.key.downTime,
              msg->body.key.eventTime);
  }
  
  void InputConsumer::initializeMotionEvent(MotionEvent* event, const InputMessage* msg) {
      uint32_t pointerCount = msg->body.motion.pointerCount;
      PointerProperties pointerProperties[pointerCount];
      PointerCoords pointerCoords[pointerCount];
      for (uint32_t i = 0; i < pointerCount; i++) {
          pointerProperties[i].copyFrom(msg->body.motion.pointers[i].properties);
          pointerCoords[i].copyFrom(msg->body.motion.pointers[i].coords);
      }
  
      event->initialize(
              msg->body.motion.deviceId,
              msg->body.motion.source,
              msg->body.motion.action,
              msg->body.motion.actionButton,
              msg->body.motion.flags,
              msg->body.motion.edgeFlags,
              msg->body.motion.metaState,
              msg->body.motion.buttonState,
              msg->body.motion.xOffset,
              msg->body.motion.yOffset,
              msg->body.motion.xPrecision,
              msg->body.motion.yPrecision,
              msg->body.motion.downTime,
              msg->body.motion.eventTime,
              pointerCount,
              pointerProperties,
              pointerCoords);
  }
  
  void InputConsumer::addSample(MotionEvent* event, const InputMessage* msg) {
      uint32_t pointerCount = msg->body.motion.pointerCount;
      PointerCoords pointerCoords[pointerCount];
      for (uint32_t i = 0; i < pointerCount; i++) {
          pointerCoords[i].copyFrom(msg->body.motion.pointers[i].coords);
      }
  
      event->setMetaState(event->getMetaState() | msg->body.motion.metaState);
      event->addSample(msg->body.motion.eventTime, pointerCoords);
  }
  
  bool InputConsumer::canAddSample(const Batch& batch, const InputMessage *msg) {
      const InputMessage& head = batch.samples.itemAt(0);
      uint32_t pointerCount = msg->body.motion.pointerCount;
      if (head.body.motion.pointerCount != pointerCount
              || head.body.motion.action != msg->body.motion.action) {
          return false;
      }
      for (size_t i = 0; i < pointerCount; i++) {
          if (head.body.motion.pointers[i].properties
                  != msg->body.motion.pointers[i].properties) {
              return false;
          }
      }
      return true;
  }
  
  ssize_t InputConsumer::findSampleNoLaterThan(const Batch& batch, nsecs_t time) {
      size_t numSamples = batch.samples.size();
      size_t index = 0;
      while (index < numSamples
              && batch.samples.itemAt(index).body.motion.eventTime <= time) {
          index += 1;
      }
      return ssize_t(index) - 1;
  }
  
  } // namespace android
  