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Commit 228bc6c0 authored by Massimo Carli's avatar Massimo Carli
Browse files

Make Letterbox.InputInterceptor thread safe 

InputEventReceiver#finishInputEvent is invoked every time
a double-tap event occurs on the ui thread and so it cannot
be guarded by the mWmService.mGlobalLock.

To avoid race conditions the common practice is to invoke
the InputEventReceiver#dispose() on the same thread dispatching
input events.

Fix: 317428610
Test: atest WmTests:LetterboxTest

Change-Id: I4cbaa9ede668a4434dd59d6a7758bec961cc1eeb
parent 0505c363

services/core/java/com/android/server/wm/Letterbox.java

+18 −8
Original line number Diff line number Diff line
@@ -23,6 +23,7 @@ import static android.window.TaskConstants.TASK_CHILD_LAYER_LETTERBOX_BACKGROUND 
import android.graphics.Color;

import android.graphics.Point;

import android.graphics.Rect;

import android.os.Handler;

import android.os.IBinder;

import android.os.InputConfig;

import android.view.GestureDetector;
@@ -258,11 +259,12 @@ public class Letterbox { 
        private final GestureDetector mDoubleTapDetector;

        private final DoubleTapListener mDoubleTapListener;



        TapEventReceiver(InputChannel inputChannel, WindowManagerService wmService) {

            super(inputChannel, UiThread.getHandler().getLooper());

        TapEventReceiver(InputChannel inputChannel, WindowManagerService wmService,

                Handler uiHandler) {

            super(inputChannel, uiHandler.getLooper());

            mDoubleTapListener = new DoubleTapListener(wmService);

            mDoubleTapDetector = new GestureDetector(

                    wmService.mContext, mDoubleTapListener, UiThread.getHandler());

            mDoubleTapDetector = new GestureDetector(wmService.mContext, mDoubleTapListener,

                    uiHandler);

        }



        @Override
@@ -294,19 +296,21 @@ public class Letterbox { 
        }

    }



    private final class InputInterceptor {

    private final class InputInterceptor implements Runnable {



        private final InputChannel mClientChannel;

        private final InputWindowHandle mWindowHandle;

        private final InputEventReceiver mInputEventReceiver;

        private final WindowManagerService mWmService;

        private final IBinder mToken;

        private final Handler mHandler;



        InputInterceptor(String namePrefix, WindowState win) {

            mWmService = win.mWmService;

            mHandler = UiThread.getHandler();

            final String name = namePrefix + (win.mActivityRecord != null ? win.mActivityRecord : win);

            mClientChannel = mWmService.mInputManager.createInputChannel(name);

            mInputEventReceiver = new TapEventReceiver(mClientChannel, mWmService);

            mInputEventReceiver = new TapEventReceiver(mClientChannel, mWmService, mHandler);



            mToken = mClientChannel.getToken();
@@ -335,11 +339,17 @@ public class Letterbox { 
            mWindowHandle.touchableRegion.translate(-frame.left, -frame.top);

        }



        void dispose() {

            mWmService.mInputManager.removeInputChannel(mToken);

        @Override

        public void run() {

            mInputEventReceiver.dispose();

            mClientChannel.dispose();

        }



        void dispose() {

            mWmService.mInputManager.removeInputChannel(mToken);

            // Perform dispose on the same thread that dispatches input event

            mHandler.post(this);

        }

    }



    private class LetterboxSurface {