Make Activites touch opaque - DO NOT MERGE

Block touches from passing through activities by adding a dedicated
surface that consumes all touches that would otherwise pass through the
bounds availble to the Activity.

Bug: 194480991
Test: atest CtsWindowManagerDeviceTestCases:ActivityRecordInputSinkTests
Test: atest CtsWindowManagerDeviceTestCases:CrossAppDragAndDropTests
Test: atest CtsWindowManagerDeviceTestCases:PinnedStackTests
Test: Manually ran through go/wm-smoke (verified pip and splitscreen
still work)
Test: Manually verfied that freeform windows work and don't consume
touches outside their bounds

Change-Id: I01b35e34a63868dead4e728a3d359ae0942302f9
(cherry picked from commit 74ce78dfb4179cb317d6e2fc3cabe5f60af5d02d)
Merged-In: I01b35e34a63868dead4e728a3d359ae0942302f9

2 files changed, 126 insertions, 0 deletions

diff --git a/services/core/java/com/android/server/wm/ActivityRecord.java b/services/core/java/com/android/server/wm/ActivityRecord.java
index dc4caf8de0fd..2108750329a6 100644
--- a/services/core/java/com/android/server/wm/ActivityRecord.java
+++ b/services/core/java/com/android/server/wm/ActivityRecord.java
@@ -673,6 +673,13 @@ final class ActivityRecord extends WindowToken implements WindowManagerService.A
 
     private AppSaturationInfo mLastAppSaturationInfo;
 
+    private final ActivityRecordInputSink mActivityRecordInputSink;
+
+    // Activities with this uid are allowed to not create an input sink while being in the same
+    // task and directly above this ActivityRecord. This field is updated whenever a new activity
+    // is launched from this ActivityRecord. Touches are always allowed within the same uid.
+    int mAllowedTouchUid;
+
     private final ColorDisplayService.ColorTransformController mColorTransformController =
             (matrix, translation) -> mWmService.mH.post(() -> {
                 synchronized (mWmService.mGlobalLock) {
@@ -1650,6 +1657,8 @@ final class ActivityRecord extends WindowToken implements WindowManagerService.A
                     ? (TaskDisplayArea) WindowContainer.fromBinder(daToken.asBinder()) : null;
             mHandoverLaunchDisplayId = options.getLaunchDisplayId();
         }
+
+        mActivityRecordInputSink = new ActivityRecordInputSink(this, sourceRecord);
     }
 
     /**
@@ -3173,6 +3182,7 @@ final class ActivityRecord extends WindowToken implements WindowManagerService.A
     @Override
     void removeImmediately() {
         onRemovedFromDisplay();
+        mActivityRecordInputSink.releaseSurfaceControl();
         super.removeImmediately();
     }
 
@@ -6048,6 +6058,9 @@ final class ActivityRecord extends WindowToken implements WindowManagerService.A
             } else if (!show && mLastSurfaceShowing) {
                 getSyncTransaction().hide(mSurfaceControl);
             }
+            if (show) {
+                mActivityRecordInputSink.applyChangesToSurfaceIfChanged(getSyncTransaction());
+            }
         }
         if (mThumbnail != null) {
             mThumbnail.setShowing(getPendingTransaction(), show);
diff --git a/services/core/java/com/android/server/wm/ActivityRecordInputSink.java b/services/core/java/com/android/server/wm/ActivityRecordInputSink.java
new file mode 100644
index 000000000000..95b5cec9a144
--- /dev/null
+++ b/services/core/java/com/android/server/wm/ActivityRecordInputSink.java
@@ -0,0 +1,113 @@
+/*
+ * Copyright (C) 2022 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.server.wm;
+
+import android.os.Process;
+import android.view.InputWindowHandle;
+import android.view.SurfaceControl;
+import android.view.WindowManager;
+
+/**
+ * Creates a InputWindowHandle that catches all touches that would otherwise pass through an
+ * Activity.
+ */
+class ActivityRecordInputSink {
+
+    private final ActivityRecord mActivityRecord;
+    private final String mName;
+
+    private InputWindowHandle mInputWindowHandle;
+    private SurfaceControl mSurfaceControl;
+
+    ActivityRecordInputSink(ActivityRecord activityRecord, ActivityRecord sourceRecord) {
+        mActivityRecord = activityRecord;
+        mName = Integer.toHexString(System.identityHashCode(this)) + " ActivityRecordInputSink "
+                + mActivityRecord.mActivityComponent.flattenToShortString();
+        if (sourceRecord != null) {
+            sourceRecord.mAllowedTouchUid = mActivityRecord.getUid();
+        }
+    }
+
+    public void applyChangesToSurfaceIfChanged(SurfaceControl.Transaction transaction) {
+        boolean windowHandleChanged = updateInputWindowHandle();
+        if (mSurfaceControl == null) {
+            mSurfaceControl = createSurface(transaction);
+        }
+        if (windowHandleChanged) {
+            transaction.setInputWindowInfo(mSurfaceControl, mInputWindowHandle);
+        }
+    }
+
+    private SurfaceControl createSurface(SurfaceControl.Transaction t) {
+        SurfaceControl surfaceControl = mActivityRecord.makeChildSurface(null)
+                .setName(mName)
+                .setHidden(false)
+                .setCallsite("ActivityRecordInputSink.createSurface")
+                .build();
+        // Put layer below all siblings (and the parent surface too)
+        t.setLayer(surfaceControl, Integer.MIN_VALUE);
+        return surfaceControl;
+    }
+
+    private boolean updateInputWindowHandle() {
+        boolean changed = false;
+        if (mInputWindowHandle == null) {
+            mInputWindowHandle = createInputWindowHandle();
+            changed = true;
+        }
+        // Don't block touches from passing through to an activity below us in the same task, if
+        // that activity is either from the same uid or if that activity has launched an activity
+        // in our uid.
+        final ActivityRecord activityBelowInTask =
+                mActivityRecord.getTask().getActivityBelow(mActivityRecord);
+        final boolean allowPassthrough = activityBelowInTask != null && (
+                activityBelowInTask.mAllowedTouchUid == mActivityRecord.getUid()
+                        || activityBelowInTask.isUid(mActivityRecord.getUid()));
+        boolean notTouchable = (mInputWindowHandle.layoutParamsFlags
+                & WindowManager.LayoutParams.FLAG_NOT_TOUCHABLE) != 0;
+        if (allowPassthrough || mActivityRecord.isAppTransitioning()) {
+            mInputWindowHandle.layoutParamsFlags |= WindowManager.LayoutParams.FLAG_NOT_TOUCHABLE;
+            changed |= !notTouchable;
+        } else {
+            mInputWindowHandle.layoutParamsFlags &= ~WindowManager.LayoutParams.FLAG_NOT_TOUCHABLE;
+            changed |= notTouchable;
+        }
+        return changed;
+    }
+
+    private InputWindowHandle createInputWindowHandle() {
+        InputWindowHandle inputWindowHandle = new InputWindowHandle(null,
+                mActivityRecord.getDisplayId());
+        inputWindowHandle.replaceTouchableRegionWithCrop = true;
+        inputWindowHandle.name = mName;
+        inputWindowHandle.layoutParamsType = WindowManager.LayoutParams.TYPE_INPUT_CONSUMER;
+        inputWindowHandle.ownerUid = Process.myUid();
+        inputWindowHandle.ownerPid = Process.myPid();
+        inputWindowHandle.layoutParamsFlags = WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE;
+        inputWindowHandle.inputFeatures =
+                WindowManager.LayoutParams.INPUT_FEATURE_NO_INPUT_CHANNEL;
+        return inputWindowHandle;
+    }
+
+    void releaseSurfaceControl() {
+        if (mSurfaceControl != null) {
+            mSurfaceControl.release();
+            mSurfaceControl = null;
+        }
+    }
+
+}