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Commit ac5f93af authored by Jimmy's avatar Jimmy
Browse files

Remove original modifiers from generated fallback keys 

Previously generated fallbacks would preserve the original modifiers,
leading to unexpected key events.
Example: Ctrl + Space -> Ctrl + language_switch

This change removes the modifiers used to trigger the fallback.
Example: Ctrl + Space -> language_switch

Fallbacks are triggered only with exact matching, so extra
modifiers will not output a fallback.
Example: Ctrl + Alt + Space -> Ctrl + Alt + Space (no fallback)

Bug: 382545048
Test: atest com.android.test.input.KeyCharacterMapTest

Flag: com.android.hardware.input.remove_fallback_modifiers

Change-Id: I78de4bc131b0c9171a3508ee560135fce6b77e42
parent 8d7d869d

core/java/android/hardware/input/input_framework.aconfig

+7 −0
Original line number Diff line number Diff line
@@ -204,3 +204,10 @@ flag { 
    description: "Allows the user to disable input scrolling acceleration for mouse."

    bug: "383555305"

}



flag {

  name: "remove_fallback_modifiers"

  namespace: "input"

  description: "Removes modifiers from the original key event that activated the fallback, ensuring that only the intended fallback event is sent."

  bug: "382545048"

}

core/java/android/view/KeyCharacterMap.java

+12 −1
Original line number Diff line number Diff line
@@ -16,6 +16,9 @@ 


package android.view;





import static com.android.hardware.input.Flags.removeFallbackModifiers;



import android.annotation.NonNull;

import android.annotation.Nullable;

import android.compat.annotation.UnsupportedAppUsage;
@@ -458,7 +461,15 @@ public class KeyCharacterMap implements Parcelable { 
        FallbackAction action = FallbackAction.obtain();

        metaState = KeyEvent.normalizeMetaState(metaState);

        if (nativeGetFallbackAction(mPtr, keyCode, metaState, action)) {

            if (removeFallbackModifiers()) {

                // Strip all modifiers. This is safe to do since only exact keyCode + metaState

                // modifiers will trigger a fallback.

                // E.g. Ctrl + Space -> language_switch (fallback generated)

                //      Ctrl + Alt + Space -> Ctrl + Alt + Space (no fallback generated)

                action.metaState = 0;

            } else {

                action.metaState = KeyEvent.normalizeMetaState(action.metaState);

            }

            return action;

        }

        action.recycle();

tests/Input/src/com/android/test/input/KeyCharacterMapTest.kt

+30 −11
Original line number Diff line number Diff line
@@ -16,10 +16,17 @@ 


package com.android.test.input



import android.platform.test.annotations.EnableFlags

import android.platform.test.flag.junit.SetFlagsRule



import android.view.KeyCharacterMap

import android.view.KeyEvent



import com.android.hardware.input.Flags



import org.junit.Assert.assertEquals

import org.junit.Assert.assertNull

import org.junit.Rule

import org.junit.Test



/**
@@ -30,26 +37,38 @@ import org.junit.Test 
 *

 */

class KeyCharacterMapTest {

    @get:Rule

    val setFlagsRule = SetFlagsRule()



    @Test

    @EnableFlags(Flags.FLAG_REMOVE_FALLBACK_MODIFIERS)

    fun testGetFallback() {

        // Based off of VIRTUAL kcm fallbacks.

        val keyCharacterMap = KeyCharacterMap.load(KeyCharacterMap.VIRTUAL_KEYBOARD)



        // One modifier fallback.

        assertEquals(

            keyCharacterMap.getFallbackAction(KeyEvent.KEYCODE_SPACE,

                KeyEvent.META_CTRL_ON).keyCode,

            KeyEvent.KEYCODE_LANGUAGE_SWITCH)

        val oneModifierFallback = keyCharacterMap.getFallbackAction(KeyEvent.KEYCODE_SPACE,

            KeyEvent.META_CTRL_ON)

        assertEquals(KeyEvent.KEYCODE_LANGUAGE_SWITCH, oneModifierFallback.keyCode)

        assertEquals(0, oneModifierFallback.metaState)



        // Multiple modifier fallback.

        assertEquals(

            keyCharacterMap.getFallbackAction(KeyEvent.KEYCODE_DEL,

                KeyEvent.META_CTRL_ON or KeyEvent.META_ALT_ON).keyCode,

            KeyEvent.KEYCODE_BACK)

        val twoModifierFallback = keyCharacterMap.getFallbackAction(KeyEvent.KEYCODE_DEL,

            KeyEvent.META_CTRL_ON or KeyEvent.META_ALT_ON)

        assertEquals(KeyEvent.KEYCODE_BACK, twoModifierFallback.keyCode)

        assertEquals(0, twoModifierFallback.metaState)



        // No default button, fallback only.

        assertEquals(

            keyCharacterMap.getFallbackAction(KeyEvent.KEYCODE_BUTTON_A, 0).keyCode,

            KeyEvent.KEYCODE_DPAD_CENTER)

        val keyOnlyFallback =

            keyCharacterMap.getFallbackAction(KeyEvent.KEYCODE_BUTTON_A, 0)

        assertEquals(KeyEvent.KEYCODE_DPAD_CENTER, keyOnlyFallback.keyCode)

        assertEquals(0, keyOnlyFallback.metaState)



        // A key event that is not an exact match for a fallback. Expect a null return.

        // E.g. Ctrl + Space -> LanguageSwitch

        //      Ctrl + Alt + Space -> Ctrl + Alt + Space (No fallback).

        val noMatchFallback = keyCharacterMap.getFallbackAction(KeyEvent.KEYCODE_SPACE,

            KeyEvent.META_CTRL_ON or KeyEvent.META_ALT_ON)

        assertNull(noMatchFallback)

    }

}