Do not assume display is available when a task launches

The resize veil creates a SCVH as soon as a task launches to draw the
icon drawable early and once to be ready for any resize operation.

However, it cannot be assumed that the DisplayController will return a
non-null display if the task and display were both launched roughly at
the same time.

To avoid a NPE, this change checks whether the display is available and
if not attaches a listener to do the resize veil set up when it actually
appears.

Bug: 333442423
Test: atest WMShellUnitTests:ResizeVeil; resize veil works as usual;
atest CtsInputTestCases doesn't cause a crash

Change-Id: Id8efb265e1910144f92fee1144aa07afb9327056

4 files changed, 340 insertions, 18 deletions

diff --git a/libs/WindowManager/Shell/src/com/android/wm/shell/windowdecor/DesktopModeWindowDecoration.java b/libs/WindowManager/Shell/src/com/android/wm/shell/windowdecor/DesktopModeWindowDecoration.java
index 963b1303c379..385e8cc5257a 100644
--- a/libs/WindowManager/Shell/src/com/android/wm/shell/windowdecor/DesktopModeWindowDecoration.java
+++ b/libs/WindowManager/Shell/src/com/android/wm/shell/windowdecor/DesktopModeWindowDecoration.java
@@ -466,8 +466,8 @@ public class DesktopModeWindowDecoration extends WindowDecoration<WindowDecorLin
      * until a resize event calls showResizeVeil below.
      */
     void createResizeVeil() {
-        mResizeVeil = new ResizeVeil(mContext, mAppIconDrawable, mTaskInfo, mTaskSurface,
-                mSurfaceControlBuilderSupplier, mDisplay, mSurfaceControlTransactionSupplier);
+        mResizeVeil = new ResizeVeil(mContext, mDisplayController, mAppIconDrawable, mTaskInfo,
+                mTaskSurface, mSurfaceControlTransactionSupplier);
     }
 
     /**
diff --git a/libs/WindowManager/Shell/src/com/android/wm/shell/windowdecor/ResizeVeil.java b/libs/WindowManager/Shell/src/com/android/wm/shell/windowdecor/ResizeVeil.java
index d072f8cec194..2c4092ac6d2c 100644
--- a/libs/WindowManager/Shell/src/com/android/wm/shell/windowdecor/ResizeVeil.java
+++ b/libs/WindowManager/Shell/src/com/android/wm/shell/windowdecor/ResizeVeil.java
@@ -20,6 +20,7 @@ import android.animation.Animator;
 import android.animation.AnimatorListenerAdapter;
 import android.animation.ValueAnimator;
 import android.annotation.ColorRes;
+import android.annotation.NonNull;
 import android.app.ActivityManager.RunningTaskInfo;
 import android.content.Context;
 import android.content.res.Configuration;
@@ -40,7 +41,7 @@ import android.widget.ImageView;
 import android.window.TaskConstants;
 
 import com.android.wm.shell.R;
-import com.android.wm.shell.common.SurfaceUtils;
+import com.android.wm.shell.common.DisplayController;
 
 import java.util.function.Supplier;
 
@@ -48,6 +49,7 @@ import java.util.function.Supplier;
  * Creates and updates a veil that covers task contents on resize.
  */
 public class ResizeVeil {
+    private static final String TAG = "ResizeVeil";
     private static final int RESIZE_ALPHA_DURATION = 100;
 
     private static final int VEIL_CONTAINER_LAYER = TaskConstants.TASK_CHILD_LAYER_RESIZE_VEIL;
@@ -57,8 +59,10 @@ public class ResizeVeil {
     private static final int VEIL_ICON_LAYER = 1;
 
     private final Context mContext;
-    private final Supplier<SurfaceControl.Builder> mSurfaceControlBuilderSupplier;
+    private final DisplayController mDisplayController;
     private final Supplier<SurfaceControl.Transaction> mSurfaceControlTransactionSupplier;
+    private final SurfaceControlBuilderFactory mSurfaceControlBuilderFactory;
+    private final WindowDecoration.SurfaceControlViewHostFactory mSurfaceControlViewHostFactory;
     private final SurfaceSession mSurfaceSession = new SurfaceSession();
     private final Drawable mAppIcon;
     private ImageView mIconView;
@@ -74,41 +78,82 @@ public class ResizeVeil {
 
     private final RunningTaskInfo mTaskInfo;
     private SurfaceControlViewHost mViewHost;
-    private final Display mDisplay;
+    private Display mDisplay;
     private ValueAnimator mVeilAnimator;
 
-    public ResizeVeil(Context context, Drawable appIcon, RunningTaskInfo taskInfo,
+    private boolean mIsShowing = false;
+
+    private final DisplayController.OnDisplaysChangedListener mOnDisplaysChangedListener =
+            new DisplayController.OnDisplaysChangedListener() {
+                @Override
+                public void onDisplayAdded(int displayId) {
+                    if (mTaskInfo.displayId != displayId) {
+                        return;
+                    }
+                    mDisplayController.removeDisplayWindowListener(this);
+                    setupResizeVeil();
+                }
+            };
+
+    public ResizeVeil(Context context,
+            @NonNull DisplayController displayController,
+            Drawable appIcon, RunningTaskInfo taskInfo,
             SurfaceControl taskSurface,
-            Supplier<SurfaceControl.Builder> surfaceControlBuilderSupplier, Display display,
             Supplier<SurfaceControl.Transaction> surfaceControlTransactionSupplier) {
+        this(context,
+                displayController,
+                appIcon,
+                taskInfo,
+                taskSurface,
+                surfaceControlTransactionSupplier,
+                new SurfaceControlBuilderFactory() {},
+                new WindowDecoration.SurfaceControlViewHostFactory() {});
+    }
+
+    public ResizeVeil(Context context,
+            @NonNull DisplayController displayController,
+            Drawable appIcon, RunningTaskInfo taskInfo,
+            SurfaceControl taskSurface,
+            Supplier<SurfaceControl.Transaction> surfaceControlTransactionSupplier,
+            SurfaceControlBuilderFactory surfaceControlBuilderFactory,
+            WindowDecoration.SurfaceControlViewHostFactory surfaceControlViewHostFactory) {
         mContext = context;
+        mDisplayController = displayController;
         mAppIcon = appIcon;
-        mSurfaceControlBuilderSupplier = surfaceControlBuilderSupplier;
         mSurfaceControlTransactionSupplier = surfaceControlTransactionSupplier;
         mTaskInfo = taskInfo;
         mParentSurface = taskSurface;
-        mDisplay = display;
+        mSurfaceControlBuilderFactory = surfaceControlBuilderFactory;
+        mSurfaceControlViewHostFactory = surfaceControlViewHostFactory;
         setupResizeVeil();
     }
-
     /**
      * Create the veil in its default invisible state.
      */
     private void setupResizeVeil() {
-        mVeilSurface = mSurfaceControlBuilderSupplier.get()
+        if (!obtainDisplayOrRegisterListener()) {
+            // Display may not be available yet, skip this until then.
+            return;
+        }
+        mVeilSurface = mSurfaceControlBuilderFactory
+                .create("Resize veil of Task=" + mTaskInfo.taskId)
                 .setContainerLayer()
-                .setName("Resize veil of Task=" + mTaskInfo.taskId)
                 .setHidden(true)
                 .setParent(mParentSurface)
                 .setCallsite("ResizeVeil#setupResizeVeil")
                 .build();
-        mBackgroundSurface = SurfaceUtils.makeColorLayer(mVeilSurface,
-                "Resize veil background of Task=" + mTaskInfo.taskId, mSurfaceSession);
-        mIconSurface = mSurfaceControlBuilderSupplier.get()
-                .setName("Resize veil icon of Task= " + mTaskInfo.taskId)
-                .setContainerLayer()
+        mBackgroundSurface = mSurfaceControlBuilderFactory
+                .create("Resize veil background of Task=" + mTaskInfo.taskId, mSurfaceSession)
+                .setColorLayer()
+                .setHidden(true)
                 .setParent(mVeilSurface)
+                .setCallsite("ResizeVeil#setupResizeVeil")
+                .build();
+        mIconSurface = mSurfaceControlBuilderFactory
+                .create("Resize veil icon of Task=" + mTaskInfo.taskId)
+                .setContainerLayer()
                 .setHidden(true)
+                .setParent(mVeilSurface)
                 .setCallsite("ResizeVeil#setupResizeVeil")
                 .build();
 
@@ -131,10 +176,20 @@ public class ResizeVeil {
 
         final WindowlessWindowManager wwm = new WindowlessWindowManager(mTaskInfo.configuration,
                 mIconSurface, null /* hostInputToken */);
-        mViewHost = new SurfaceControlViewHost(mContext, mDisplay, wwm, "ResizeVeil");
+
+        mViewHost = mSurfaceControlViewHostFactory.create(mContext, mDisplay, wwm, "ResizeVeil");
         mViewHost.setView(root, lp);
     }
 
+    private boolean obtainDisplayOrRegisterListener() {
+        mDisplay = mDisplayController.getDisplay(mTaskInfo.displayId);
+        if (mDisplay == null) {
+            mDisplayController.addDisplayWindowListener(mOnDisplaysChangedListener);
+            return false;
+        }
+        return true;
+    }
+
     /**
      * Shows the veil surface/view.
      *
@@ -146,6 +201,12 @@ public class ResizeVeil {
      */
     public void showVeil(SurfaceControl.Transaction t, SurfaceControl parentSurface,
             Rect taskBounds, boolean fadeIn) {
+        if (!isReady() || isVisible()) {
+            t.apply();
+            return;
+        }
+        mIsShowing = true;
+
         // Parent surface can change, ensure it is up to date.
         if (!parentSurface.equals(mParentSurface)) {
             t.reparent(mVeilSurface, parentSurface);
@@ -226,6 +287,9 @@ public class ResizeVeil {
      * Animate veil's alpha to 1, fading it in.
      */
     public void showVeil(SurfaceControl parentSurface, Rect taskBounds) {
+        if (!isReady() || isVisible()) {
+            return;
+        }
         SurfaceControl.Transaction t = mSurfaceControlTransactionSupplier.get();
         showVeil(t, parentSurface, taskBounds, true /* fadeIn */);
     }
@@ -247,6 +311,9 @@ public class ResizeVeil {
      * @param newBounds bounds to update veil to.
      */
     public void updateResizeVeil(Rect newBounds) {
+        if (!isVisible()) {
+            return;
+        }
         SurfaceControl.Transaction t = mSurfaceControlTransactionSupplier.get();
         updateResizeVeil(t, newBounds);
     }
@@ -260,6 +327,10 @@ public class ResizeVeil {
      * @param newBounds bounds to update veil to.
      */
     public void updateResizeVeil(SurfaceControl.Transaction t, Rect newBounds) {
+        if (!isVisible()) {
+            t.apply();
+            return;
+        }
         if (mVeilAnimator != null && mVeilAnimator.isStarted()) {
             mVeilAnimator.removeAllUpdateListeners();
             mVeilAnimator.end();
@@ -272,6 +343,9 @@ public class ResizeVeil {
      * Animate veil's alpha to 0, fading it out.
      */
     public void hideVeil() {
+        if (!isVisible()) {
+            return;
+        }
         cancelAnimation();
         mVeilAnimator = new ValueAnimator();
         mVeilAnimator.setFloatValues(1, 0);
@@ -292,6 +366,7 @@ public class ResizeVeil {
             }
         });
         mVeilAnimator.start();
+        mIsShowing = false;
     }
 
     @ColorRes
@@ -318,10 +393,26 @@ public class ResizeVeil {
     }
 
     /**
+     * Whether the resize veil is currently visible.
+     *
+     * Note: when animating a {@link ResizeVeil#hideVeil()}, the veil is considered visible as soon
+     * as the animation starts.
+     */
+    private boolean isVisible() {
+        return mIsShowing;
+    }
+
+    /** Whether the resize veil is ready to be shown. */
+    private boolean isReady() {
+        return mViewHost != null;
+    }
+
+    /**
      * Dispose of veil when it is no longer needed, likely on close of its container decor.
      */
     void dispose() {
         cancelAnimation();
+        mIsShowing = false;
         mVeilAnimator = null;
 
         if (mViewHost != null) {
@@ -342,5 +433,16 @@ public class ResizeVeil {
             mVeilSurface = null;
         }
         t.apply();
+        mDisplayController.removeDisplayWindowListener(mOnDisplaysChangedListener);
+    }
+
+    interface SurfaceControlBuilderFactory {
+        default SurfaceControl.Builder create(@NonNull String name) {
+            return new SurfaceControl.Builder().setName(name);
+        }
+        default SurfaceControl.Builder create(@NonNull String name,
+                @NonNull SurfaceSession surfaceSession) {
+            return new SurfaceControl.Builder(surfaceSession).setName(name);
+        }
     }
 }
diff --git a/libs/WindowManager/Shell/src/com/android/wm/shell/windowdecor/WindowDecoration.java b/libs/WindowManager/Shell/src/com/android/wm/shell/windowdecor/WindowDecoration.java
index 51b0a246f3e9..36da1ace8408 100644
--- a/libs/WindowManager/Shell/src/com/android/wm/shell/windowdecor/WindowDecoration.java
+++ b/libs/WindowManager/Shell/src/com/android/wm/shell/windowdecor/WindowDecoration.java
@@ -668,6 +668,10 @@ public abstract class WindowDecoration<T extends View & TaskFocusStateConsumer>
         default SurfaceControlViewHost create(Context c, Display d, WindowlessWindowManager wmm) {
             return new SurfaceControlViewHost(c, d, wmm, "WindowDecoration");
         }
+        default SurfaceControlViewHost create(Context c, Display d,
+                WindowlessWindowManager wmm, String callsite) {
+            return new SurfaceControlViewHost(c, d, wmm, callsite);
+        }
     }
 
     /**
diff --git a/libs/WindowManager/Shell/tests/unittest/src/com/android/wm/shell/windowdecor/ResizeVeilTest.kt b/libs/WindowManager/Shell/tests/unittest/src/com/android/wm/shell/windowdecor/ResizeVeilTest.kt
new file mode 100644
index 000000000000..847c2dd77d0a
--- /dev/null
+++ b/libs/WindowManager/Shell/tests/unittest/src/com/android/wm/shell/windowdecor/ResizeVeilTest.kt
@@ -0,0 +1,216 @@
+/*
+ * Copyright (C) 2024 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.android.wm.shell.windowdecor
+
+import android.graphics.Rect
+import android.graphics.drawable.Drawable
+import android.testing.AndroidTestingRunner
+import android.testing.TestableLooper
+import android.view.Display
+import android.view.SurfaceControl
+import android.view.SurfaceControlViewHost
+import android.view.WindowlessWindowManager
+import androidx.test.filters.SmallTest
+import com.android.wm.shell.ShellTestCase
+import com.android.wm.shell.TestRunningTaskInfoBuilder
+import com.android.wm.shell.common.DisplayController
+import com.android.wm.shell.common.DisplayController.OnDisplaysChangedListener
+import com.android.wm.shell.windowdecor.WindowDecoration.SurfaceControlViewHostFactory
+import org.junit.Before
+import org.junit.Test
+import org.junit.runner.RunWith
+import org.mockito.ArgumentCaptor
+import org.mockito.Mock
+import org.mockito.Spy
+import org.mockito.kotlin.any
+import org.mockito.kotlin.doReturn
+import org.mockito.kotlin.eq
+import org.mockito.kotlin.mock
+import org.mockito.kotlin.never
+import org.mockito.kotlin.times
+import org.mockito.kotlin.verify
+import org.mockito.kotlin.verifyZeroInteractions
+import org.mockito.kotlin.whenever
+
+
+/**
+ * Tests for [ResizeVeil].
+ *
+ * Build/Install/Run:
+ * atest WMShellUnitTests:ResizeVeilTest
+ */
+@SmallTest
+@RunWith(AndroidTestingRunner::class)
+@TestableLooper.RunWithLooper
+class ResizeVeilTest : ShellTestCase() {
+
+    @Mock
+    private lateinit var mockDisplayController: DisplayController
+    @Mock
+    private lateinit var mockAppIcon: Drawable
+    @Mock
+    private lateinit var mockDisplay: Display
+    @Mock
+    private lateinit var mockSurfaceControlViewHost: SurfaceControlViewHost
+    @Mock
+    private lateinit var mockSurfaceControlBuilderFactory: ResizeVeil.SurfaceControlBuilderFactory
+    @Mock
+    private lateinit var mockSurfaceControlViewHostFactory: SurfaceControlViewHostFactory
+    @Spy
+    private val spyResizeVeilSurfaceBuilder = SurfaceControl.Builder()
+    @Mock
+    private lateinit var mockResizeVeilSurface: SurfaceControl
+    @Spy
+    private val spyBackgroundSurfaceBuilder = SurfaceControl.Builder()
+    @Mock
+    private lateinit var mockBackgroundSurface: SurfaceControl
+    @Spy
+    private val spyIconSurfaceBuilder = SurfaceControl.Builder()
+    @Mock
+    private lateinit var mockIconSurface: SurfaceControl
+    @Mock
+    private lateinit var mockTransaction: SurfaceControl.Transaction
+
+    private val taskInfo = TestRunningTaskInfoBuilder().build()
+
+    @Before
+    fun setUp() {
+        whenever(mockSurfaceControlViewHostFactory.create(any(), any(), any(), any()))
+                .thenReturn(mockSurfaceControlViewHost)
+        whenever(mockSurfaceControlBuilderFactory
+            .create("Resize veil of Task=" + taskInfo.taskId))
+            .thenReturn(spyResizeVeilSurfaceBuilder)
+        doReturn(mockResizeVeilSurface).whenever(spyResizeVeilSurfaceBuilder).build()
+        whenever(mockSurfaceControlBuilderFactory
+            .create(eq("Resize veil background of Task=" + taskInfo.taskId), any()))
+            .thenReturn(spyBackgroundSurfaceBuilder)
+        doReturn(mockBackgroundSurface).whenever(spyBackgroundSurfaceBuilder).build()
+        whenever(mockSurfaceControlBuilderFactory
+            .create("Resize veil icon of Task=" + taskInfo.taskId))
+            .thenReturn(spyIconSurfaceBuilder)
+        doReturn(mockIconSurface).whenever(spyIconSurfaceBuilder).build()
+    }
+
+    @Test
+    fun init_displayAvailable_viewHostCreated() {
+        createResizeVeil(withDisplayAvailable = true)
+
+        verify(mockSurfaceControlViewHostFactory)
+            .create(any(), eq(mockDisplay), any(), eq("ResizeVeil"))
+    }
+
+    @Test
+    fun init_displayUnavailable_viewHostNotCreatedUntilDisplayAppears() {
+        createResizeVeil(withDisplayAvailable = false)
+
+        verify(mockSurfaceControlViewHostFactory, never())
+            .create(any(), eq(mockDisplay), any<WindowlessWindowManager>(), eq("ResizeVeil"))
+        val captor = ArgumentCaptor.forClass(OnDisplaysChangedListener::class.java)
+        verify(mockDisplayController).addDisplayWindowListener(captor.capture())
+
+        whenever(mockDisplayController.getDisplay(taskInfo.displayId)).thenReturn(mockDisplay)
+        captor.value.onDisplayAdded(taskInfo.displayId)
+
+        verify(mockSurfaceControlViewHostFactory)
+            .create(any(), eq(mockDisplay), any(), eq("ResizeVeil"))
+        verify(mockDisplayController).removeDisplayWindowListener(any())
+    }
+
+    @Test
+    fun dispose_removesDisplayWindowListener() {
+        createResizeVeil().dispose()
+
+        verify(mockDisplayController).removeDisplayWindowListener(any())
+    }
+
+    @Test
+    fun showVeil() {
+        val veil = createResizeVeil()
+        val tx = mock<SurfaceControl.Transaction>()
+
+        veil.showVeil(tx, mock(), Rect(0, 0, 100, 100), false /* fadeIn */)
+
+        verify(tx).show(mockResizeVeilSurface)
+        verify(tx).show(mockBackgroundSurface)
+        verify(tx).show(mockIconSurface)
+        verify(tx).apply()
+    }
+
+    @Test
+    fun showVeil_displayUnavailable_doesNotShow() {
+        val veil = createResizeVeil(withDisplayAvailable = false)
+        val tx = mock<SurfaceControl.Transaction>()
+
+        veil.showVeil(tx, mock(), Rect(0, 0, 100, 100), false /* fadeIn */)
+
+        verify(tx, never()).show(mockResizeVeilSurface)
+        verify(tx, never()).show(mockBackgroundSurface)
+        verify(tx, never()).show(mockIconSurface)
+        verify(tx).apply()
+    }
+
+    @Test
+    fun showVeil_alreadyVisible_doesNotShowAgain() {
+        val veil = createResizeVeil()
+        val tx = mock<SurfaceControl.Transaction>()
+
+        veil.showVeil(tx, mock(), Rect(0, 0, 100, 100), false /* fadeIn */)
+        veil.showVeil(tx, mock(), Rect(0, 0, 100, 100), false /* fadeIn */)
+
+        verify(tx, times(1)).show(mockResizeVeilSurface)
+        verify(tx, times(1)).show(mockBackgroundSurface)
+        verify(tx, times(1)).show(mockIconSurface)
+        verify(tx, times(2)).apply()
+    }
+
+    @Test
+    fun showVeil_reparentsVeilToNewParent() {
+        val veil = createResizeVeil(parent = mock())
+        val tx = mock<SurfaceControl.Transaction>()
+
+        val newParent = mock<SurfaceControl>()
+        veil.showVeil(tx, newParent, Rect(0, 0, 100, 100), false /* fadeIn */)
+
+        verify(tx).reparent(mockResizeVeilSurface, newParent)
+    }
+
+    @Test
+    fun hideVeil_alreadyHidden_doesNothing() {
+        val veil = createResizeVeil()
+
+        veil.hideVeil()
+
+        verifyZeroInteractions(mockTransaction)
+    }
+
+    private fun createResizeVeil(
+        withDisplayAvailable: Boolean = true,
+        parent: SurfaceControl = mock()
+    ): ResizeVeil {
+        whenever(mockDisplayController.getDisplay(taskInfo.displayId))
+            .thenReturn(if (withDisplayAvailable) mockDisplay else null)
+        return ResizeVeil(
+            context,
+            mockDisplayController,
+            mockAppIcon,
+            taskInfo,
+            parent,
+            { mockTransaction },
+            mockSurfaceControlBuilderFactory,
+            mockSurfaceControlViewHostFactory
+        )
+    }
+}