Filter virtual keys after touches.  (DO NOT MERGE)

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: Id6733c83c2e2bc8d9553aa0e5c1fd74b741bec6e
diff --git a/include/ui/InputReader.h b/include/ui/InputReader.h
index 49351b0..7568ba7 100644
--- a/include/ui/InputReader.h
+++ b/include/ui/InputReader.h
@@ -103,6 +103,12 @@
      */
     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 configured virtual key definitions for an input device. */
     virtual void getVirtualKeyDefinitions(const String8& deviceName,
             Vector<VirtualKeyDefinition>& outVirtualKeyDefinitions) = 0;
@@ -177,6 +183,10 @@
     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;
@@ -264,6 +274,11 @@
     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,
@@ -585,6 +600,7 @@
         bool useBadTouchFilter;
         bool useJumpyTouchFilter;
         bool useAveragingTouchFilter;
+        nsecs_t virtualKeyQuietTime;
     } mParameters;
 
     // Immutable calibration parameters in parsed form.
@@ -810,6 +826,7 @@
     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/libs/ui/InputReader.cpp b/libs/ui/InputReader.cpp
index 3197ab2..83b382b 100644
--- a/libs/ui/InputReader.cpp
+++ b/libs/ui/InputReader.cpp
@@ -198,7 +198,7 @@
         const sp<InputReaderPolicyInterface>& policy,
         const sp<InputDispatcherInterface>& dispatcher) :
         mEventHub(eventHub), mPolicy(policy), mDispatcher(dispatcher),
-        mGlobalMetaState(0) {
+        mGlobalMetaState(0), mDisableVirtualKeysTimeout(-1) {
     configureExcludedDevices();
     updateGlobalMetaState();
     updateInputConfiguration();
@@ -453,6 +453,24 @@
     } // 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);
@@ -937,6 +955,11 @@
                 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;
@@ -1340,6 +1363,7 @@
     mParameters.useBadTouchFilter = getPolicy()->filterTouchEvents();
     mParameters.useAveragingTouchFilter = getPolicy()->filterTouchEvents();
     mParameters.useJumpyTouchFilter = getPolicy()->filterJumpyTouchEvents();
+    mParameters.virtualKeyQuietTime = getPolicy()->getVirtualKeyQuietTime();
 }
 
 void TouchInputMapper::dumpParameters(String8& dump) {
@@ -2060,6 +2084,7 @@
 
     TouchResult touchResult = consumeOffScreenTouches(when, policyFlags);
     if (touchResult == DISPATCH_TOUCH) {
+        detectGestures(when);
         dispatchTouches(when, policyFlags);
     }
 
@@ -2145,6 +2170,11 @@
                     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;
@@ -2182,6 +2212,26 @@
     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/libs/ui/tests/InputReader_test.cpp b/libs/ui/tests/InputReader_test.cpp
index de4b05a..f31a6be 100644
--- a/libs/ui/tests/InputReader_test.cpp
+++ b/libs/ui/tests/InputReader_test.cpp
@@ -131,6 +131,10 @@
         return mFilterJumpyTouchEvents;
     }
 
+    virtual nsecs_t getVirtualKeyQuietTime() {
+        return 0;
+    }
+
     virtual void getVirtualKeyDefinitions(const String8& deviceName,
             Vector<VirtualKeyDefinition>& outVirtualKeyDefinitions) {
         ssize_t index = mVirtualKeyDefinitions.indexOfKey(deviceName);
@@ -631,6 +635,14 @@
     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;
+    }
 };