Cancel touch events when a low-level touch gesture occurs.

When the touch firmware or driver sends a key event that is triggered
by a low-level gesture such as a palm slap.  For this to work, the
touch device's .kl file must specify the "GESTURE" flag for each
key that is produced by a gesture.

Note that the "VIRTUAL" flag should also be specified for any such
keys for which we would like to generate haptic feedback.

eg. key 142   SLEEP   VIRTUAL GESTURE

Bug: 19264992
Change-Id: Ief494ec7e3ca66d2358a1001fdfae4f263ee1cd1

include/input/Input.h

@@ -149,10 +149,22 @@ enum {
      * NOTE: If you want a flag to be able to set in a keylayout file, then you must add it to
      * InputEventLabels.h as well. */
 
+    // Indicates that the event should wake the device.
     POLICY_FLAG_WAKE = 0x00000001,
+
+    // Indicates that the key is virtual, such as a capacitive button, and should
+    // generate haptic feedback.  Virtual keys may be suppressed for some time
+    // after a recent touch to prevent accidental activation of virtual keys adjacent
+    // to the touch screen during an edge swipe.
     POLICY_FLAG_VIRTUAL = 0x00000002,
+
+    // Indicates that the key is the special function modifier.
     POLICY_FLAG_FUNCTION = 0x00000004,
 
+    // Indicates that the key represents a special gesture that has been detected by
+    // the touch firmware or driver.  Causes touch events from the same device to be canceled.
+    POLICY_FLAG_GESTURE = 0x00000008,
+
     POLICY_FLAG_RAW_MASK = 0x0000ffff,
 
     /* These flags are set by the input dispatcher. */

include/input/InputEventLabels.h

@@ -376,6 +376,7 @@ static const InputEventLabel LEDS[] = {
 static const InputEventLabel FLAGS[] = {
     DEFINE_FLAG(VIRTUAL),
     DEFINE_FLAG(FUNCTION),
+    DEFINE_FLAG(GESTURE),
 
     { NULL, 0 }
 };

services/inputflinger/InputReader.cpp

@@ -1078,6 +1078,14 @@ void InputDevice::cancelVibrate(int32_t token) {
     }
 }
 
+void InputDevice::cancelTouch(nsecs_t when) {
+    size_t numMappers = mMappers.size();
+    for (size_t i = 0; i < numMappers; i++) {
+        InputMapper* mapper = mMappers[i];
+        mapper->cancelTouch(when);
+    }
+}
+
 int32_t InputDevice::getMetaState() {
     int32_t result = 0;
     size_t numMappers = mMappers.size();
@@ -1786,6 +1794,9 @@ void InputMapper::vibrate(const nsecs_t* pattern, size_t patternSize, ssize_t re
 void InputMapper::cancelVibrate(int32_t token) {
 }
 
+void InputMapper::cancelTouch(nsecs_t when) {
+}
+
 int32_t InputMapper::getMetaState() {
     return 0;
 }
@@ -2134,6 +2145,9 @@ void KeyboardInputMapper::processKey(nsecs_t when, bool down, int32_t keyCode,
                             getDevice(), keyCode, scanCode)) {
                 return;
             }
+            if (policyFlags & POLICY_FLAG_GESTURE) {
+                mDevice->cancelTouch(when);
+            }
 
             mKeyDowns.push();
             KeyDown& keyDown = mKeyDowns.editTop();
@@ -5717,6 +5731,10 @@ void TouchInputMapper::fadePointer() {
     }
 }
 
+void TouchInputMapper::cancelTouch(nsecs_t when) {
+    abortPointerUsage(when, 0 /*policyFlags*/);
+}
+
 bool TouchInputMapper::isPointInsideSurface(int32_t x, int32_t y) {
     return x >= mRawPointerAxes.x.minValue && x <= mRawPointerAxes.x.maxValue
             && y >= mRawPointerAxes.y.minValue && y <= mRawPointerAxes.y.maxValue;

services/inputflinger/InputReader.h

@@ -572,6 +572,7 @@ public:
             const int32_t* keyCodes, uint8_t* outFlags);
     void vibrate(const nsecs_t* pattern, size_t patternSize, ssize_t repeat, int32_t token);
     void cancelVibrate(int32_t token);
+    void cancelTouch(nsecs_t when);
 
     int32_t getMetaState();
 
@@ -973,6 +974,7 @@ public:
     virtual void vibrate(const nsecs_t* pattern, size_t patternSize, ssize_t repeat,
             int32_t token);
     virtual void cancelVibrate(int32_t token);
+    virtual void cancelTouch(nsecs_t when);
 
     virtual int32_t getMetaState();
 
@@ -1191,6 +1193,7 @@ public:
             const int32_t* keyCodes, uint8_t* outFlags);
 
     virtual void fadePointer();
+    virtual void cancelTouch(nsecs_t when);
     virtual void timeoutExpired(nsecs_t when);
 
 protected: