Filter virtual keys after touches.

Adds a new virtualKeyQuietTimeMillis configuration resource that sets
the duration for which virtual keys will be dropped after recent touches
on screen.  The default value is 0; it is intended to be overridden
per device using a resource overlay.

This change is designed to help in two cases:

1. Swipes from touchscreen into virtual key area.
2. Accidental taps in virtual key area while using on-screen keyboard.

Bug: 3089163
Change-Id: Ib912d4f8a4df9966a39cd537d3ec7c24afab7225

3 files changed, 81 insertions, 1 deletions

diff --git a/services/input/InputReader.cpp b/services/input/InputReader.cpp
index 6b66791..8e9a5a4 100644
--- a/services/input/InputReader.cpp
+++ b/services/input/InputReader.cpp
@@ -121,7 +121,7 @@ InputReader::InputReader(const sp<EventHubInterface>& eventHub,
         const sp<InputReaderPolicyInterface>& policy,
         const sp<InputDispatcherInterface>& dispatcher) :
         mEventHub(eventHub), mPolicy(policy), mDispatcher(dispatcher),
-        mGlobalMetaState(0) {
+        mGlobalMetaState(0), mDisableVirtualKeysTimeout(-1) {
     configureExcludedDevices();
     updateGlobalMetaState();
     updateInputConfiguration();
@@ -373,6 +373,24 @@ void InputReader::updateInputConfiguration() {
     } // release state lock
 }
 
+void InputReader::disableVirtualKeysUntil(nsecs_t time) {
+    mDisableVirtualKeysTimeout = time;
+}
+
+bool InputReader::shouldDropVirtualKey(nsecs_t now,
+        InputDevice* device, int32_t keyCode, int32_t scanCode) {
+    if (now < mDisableVirtualKeysTimeout) {
+        LOGI("Dropping virtual key from device %s because virtual keys are "
+                "temporarily disabled for the next %0.3fms.  keyCode=%d, scanCode=%d",
+                device->getName().string(),
+                (mDisableVirtualKeysTimeout - now) * 0.000001,
+                keyCode, scanCode);
+        return true;
+    } else {
+        return false;
+    }
+}
+
 void InputReader::getInputConfiguration(InputConfiguration* outConfiguration) {
     { // acquire state lock
         AutoMutex _l(mStateLock);
@@ -889,6 +907,12 @@ void KeyboardInputMapper::processKey(nsecs_t when, bool down, int32_t keyCode,
                 keyCode = mLocked.keyDowns.itemAt(keyDownIndex).keyCode;
             } else {
                 // key down
+                if ((policyFlags & POLICY_FLAG_VIRTUAL)
+                        && mContext->shouldDropVirtualKey(when,
+                                getDevice(), keyCode, scanCode)) {
+                    return;
+                }
+
                 mLocked.keyDowns.push();
                 KeyDown& keyDown = mLocked.keyDowns.editTop();
                 keyDown.keyCode = keyCode;
@@ -1428,6 +1452,7 @@ void TouchInputMapper::configureParameters() {
     mParameters.useBadTouchFilter = getPolicy()->filterTouchEvents();
     mParameters.useAveragingTouchFilter = getPolicy()->filterTouchEvents();
     mParameters.useJumpyTouchFilter = getPolicy()->filterJumpyTouchEvents();
+    mParameters.virtualKeyQuietTime = getPolicy()->getVirtualKeyQuietTime();
 
     String8 deviceTypeString;
     mParameters.deviceType = Parameters::DEVICE_TYPE_TOUCH_SCREEN;
@@ -2219,6 +2244,7 @@ void TouchInputMapper::syncTouch(nsecs_t when, bool havePointerIds) {
 
     TouchResult touchResult = consumeOffScreenTouches(when, policyFlags);
     if (touchResult == DISPATCH_TOUCH) {
+        detectGestures(when);
         dispatchTouches(when, policyFlags);
     }
 
@@ -2304,6 +2330,11 @@ TouchInputMapper::TouchResult TouchInputMapper::consumeOffScreenTouches(
                     if (mCurrentTouch.pointerCount == 1) {
                         const VirtualKey* virtualKey = findVirtualKeyHitLocked(x, y);
                         if (virtualKey) {
+                            if (mContext->shouldDropVirtualKey(when, getDevice(),
+                                    virtualKey->keyCode, virtualKey->scanCode)) {
+                                return DROP_STROKE;
+                            }
+
                             mLocked.currentVirtualKey.down = true;
                             mLocked.currentVirtualKey.downTime = when;
                             mLocked.currentVirtualKey.keyCode = virtualKey->keyCode;
@@ -2341,6 +2372,26 @@ TouchInputMapper::TouchResult TouchInputMapper::consumeOffScreenTouches(
     return touchResult;
 }
 
+void TouchInputMapper::detectGestures(nsecs_t when) {
+    // Disable all virtual key touches that happen within a short time interval of the
+    // most recent touch.  The idea is to filter out stray virtual key presses when
+    // interacting with the touch screen.
+    //
+    // Problems we're trying to solve:
+    //
+    // 1. While scrolling a list or dragging the window shade, the user swipes down into a
+    //    virtual key area that is implemented by a separate touch panel and accidentally
+    //    triggers a virtual key.
+    //
+    // 2. While typing in the on screen keyboard, the user taps slightly outside the screen
+    //    area and accidentally triggers a virtual key.  This often happens when virtual keys
+    //    are layed out below the screen near to where the on screen keyboard's space bar
+    //    is displayed.
+    if (mParameters.virtualKeyQuietTime > 0 && mCurrentTouch.pointerCount != 0) {
+        mContext->disableVirtualKeysUntil(when + mParameters.virtualKeyQuietTime);
+    }
+}
+
 void TouchInputMapper::dispatchTouches(nsecs_t when, uint32_t policyFlags) {
     uint32_t currentPointerCount = mCurrentTouch.pointerCount;
     uint32_t lastPointerCount = mLastTouch.pointerCount;
diff --git a/services/input/InputReader.h b/services/input/InputReader.h
index 8b2d40a..7619682 100644
--- a/services/input/InputReader.h
+++ b/services/input/InputReader.h
@@ -78,6 +78,12 @@ public:
      */
     virtual bool filterJumpyTouchEvents() = 0;
 
+    /* Gets the amount of time to disable virtual keys after the screen is touched
+     * in order to filter out accidental virtual key presses due to swiping gestures
+     * or taps near the edge of the display.  May be 0 to disable the feature.
+     */
+    virtual nsecs_t getVirtualKeyQuietTime() = 0;
+
     /* Gets the excluded device names for the platform. */
     virtual void getExcludedDeviceNames(Vector<String8>& outExcludedDeviceNames) = 0;
 
@@ -147,6 +153,10 @@ public:
     virtual void updateGlobalMetaState() = 0;
     virtual int32_t getGlobalMetaState() = 0;
 
+    virtual void disableVirtualKeysUntil(nsecs_t time) = 0;
+    virtual bool shouldDropVirtualKey(nsecs_t now,
+            InputDevice* device, int32_t keyCode, int32_t scanCode) = 0;
+
     virtual InputReaderPolicyInterface* getPolicy() = 0;
     virtual InputDispatcherInterface* getDispatcher() = 0;
     virtual EventHubInterface* getEventHub() = 0;
@@ -234,6 +244,11 @@ private:
     InputConfiguration mInputConfiguration;
     void updateInputConfiguration();
 
+    nsecs_t mDisableVirtualKeysTimeout;
+    virtual void disableVirtualKeysUntil(nsecs_t time);
+    virtual bool shouldDropVirtualKey(nsecs_t now,
+            InputDevice* device, int32_t keyCode, int32_t scanCode);
+
     // state queries
     typedef int32_t (InputDevice::*GetStateFunc)(uint32_t sourceMask, int32_t code);
     int32_t getState(int32_t deviceId, uint32_t sourceMask, int32_t code,
@@ -603,6 +618,7 @@ protected:
         bool useBadTouchFilter;
         bool useJumpyTouchFilter;
         bool useAveragingTouchFilter;
+        nsecs_t virtualKeyQuietTime;
     } mParameters;
 
     // Immutable calibration parameters in parsed form.
@@ -839,6 +855,7 @@ private:
     void dispatchTouch(nsecs_t when, uint32_t policyFlags, TouchData* touch,
             BitSet32 idBits, uint32_t changedId, uint32_t pointerCount,
             int32_t motionEventAction);
+    void detectGestures(nsecs_t when);
 
     bool isPointInsideSurfaceLocked(int32_t x, int32_t y);
     const VirtualKey* findVirtualKeyHitLocked(int32_t x, int32_t y);
diff --git a/services/input/tests/InputReader_test.cpp b/services/input/tests/InputReader_test.cpp
index 8ec6f53..775747c 100644
--- a/services/input/tests/InputReader_test.cpp
+++ b/services/input/tests/InputReader_test.cpp
@@ -127,6 +127,10 @@ public:
         mFilterJumpyTouchEvents = enabled;
     }
 
+    virtual nsecs_t getVirtualKeyQuietTime() {
+        return 0;
+    }
+
     void addExcludedDeviceName(const String8& deviceName) {
         mExcludedDeviceNames.push(deviceName);
     }
@@ -722,6 +726,14 @@ private:
     virtual InputDispatcherInterface* getDispatcher() {
         return mDispatcher.get();
     }
+
+    virtual void disableVirtualKeysUntil(nsecs_t time) {
+    }
+
+    virtual bool shouldDropVirtualKey(nsecs_t now,
+            InputDevice* device, int32_t keyCode, int32_t scanCode) {
+        return false;
+    }
 };