From a5858ed4e44fbc1b6c291d2e7506952f95633b06 Mon Sep 17 00:00:00 2001
From: Evan Rosky <erosky@google.com>
Date: Tue, 21 Apr 2020 18:47:37 -0700
Subject: [PATCH] Ignore task-info changed callbacks in uninitialized Divider

Apparently there is a chance that SysUI crashes without
system server receiving binder-death (or maybe it receives
binder-death too late?). In this situation, when sys-ui
restarts, the split root-tasks will still exist so there is
a small window of time during init() where WM might send
messages to the new organizer before init() finishes
running.

This avoids a cycle of crashes by returning early, but if
this is hit, the system is likely in a weird state and
Divider probably won't work.

Bug: 153811023
Test: Will need to wait and see. Too low repro rate.
Change-Id: Id42569b4699699dbc7eaa63eaff801c7c52314c7
---
 .../stackdivider/SplitScreenTaskOrganizer.java     | 14 ++++++++++----
 .../systemui/stackdivider/WindowManagerProxy.java  |  5 -----
 2 files changed, 10 insertions(+), 9 deletions(-)

diff --git a/packages/SystemUI/src/com/android/systemui/stackdivider/SplitScreenTaskOrganizer.java b/packages/SystemUI/src/com/android/systemui/stackdivider/SplitScreenTaskOrganizer.java
index a4b1310687aa7..f5d6cb6fd4b0a 100644
--- a/packages/SystemUI/src/com/android/systemui/stackdivider/SplitScreenTaskOrganizer.java
+++ b/packages/SystemUI/src/com/android/systemui/stackdivider/SplitScreenTaskOrganizer.java
@@ -33,10 +33,8 @@ import android.view.SurfaceControl;
 import android.view.SurfaceSession;
 import android.window.TaskOrganizer;
 
-import java.util.ArrayList;
-
 class SplitScreenTaskOrganizer extends TaskOrganizer {
-    private static final String TAG = "SplitScreenTaskOrganizer";
+    private static final String TAG = "SplitScreenTaskOrg";
     private static final boolean DEBUG = Divider.DEBUG;
 
     RunningTaskInfo mPrimary;
@@ -45,7 +43,6 @@ class SplitScreenTaskOrganizer extends TaskOrganizer {
     SurfaceControl mSecondarySurface;
     SurfaceControl mPrimaryDim;
     SurfaceControl mSecondaryDim;
-    ArrayList<SurfaceControl> mHomeAndRecentsSurfaces = new ArrayList<>();
     Rect mHomeBounds = new Rect();
     final Divider mDivider;
     private boolean mSplitScreenSupported = false;
@@ -110,6 +107,15 @@ class SplitScreenTaskOrganizer extends TaskOrganizer {
      * presentations based on the contents of the split regions.
      */
     private void handleTaskInfoChanged(RunningTaskInfo info) {
+        if (!mSplitScreenSupported) {
+            // This shouldn't happen; but apparently there is a chance that SysUI crashes without
+            // system server receiving binder-death (or maybe it receives binder-death too late?).
+            // In this situation, when sys-ui restarts, the split root-tasks will still exist so
+            // there is a small window of time during init() where WM might send messages here
+            // before init() fails. So, avoid a cycle of crashes by returning early.
+            Log.e(TAG, "Got handleTaskInfoChanged when not initialized: " + info);
+            return;
+        }
         final boolean secondaryWasHomeOrRecents = mSecondary.topActivityType == ACTIVITY_TYPE_HOME
                 || mSecondary.topActivityType == ACTIVITY_TYPE_RECENTS;
         final boolean primaryWasEmpty = mPrimary.topActivityType == ACTIVITY_TYPE_UNDEFINED;
diff --git a/packages/SystemUI/src/com/android/systemui/stackdivider/WindowManagerProxy.java b/packages/SystemUI/src/com/android/systemui/stackdivider/WindowManagerProxy.java
index 5aa7946bcb7f4..3027bd225216c 100644
--- a/packages/SystemUI/src/com/android/systemui/stackdivider/WindowManagerProxy.java
+++ b/packages/SystemUI/src/com/android/systemui/stackdivider/WindowManagerProxy.java
@@ -174,12 +174,8 @@ public class WindowManagerProxy {
         if (rootTasks.isEmpty()) {
             return false;
         }
-        tiles.mHomeAndRecentsSurfaces.clear();
         for (int i = rootTasks.size() - 1; i >= 0; --i) {
             final ActivityManager.RunningTaskInfo rootTask = rootTasks.get(i);
-            if (isHomeOrRecentTask(rootTask)) {
-                tiles.mHomeAndRecentsSurfaces.add(rootTask.token.getLeash());
-            }
             // Only move resizeable task to split secondary. WM will just ignore this anyways...
             if (!rootTask.isResizable()) continue;
             // Only move fullscreen tasks to split secondary.
@@ -211,7 +207,6 @@ public class WindowManagerProxy {
         // Set launch root first so that any task created after getChildContainers and
         // before reparent (pretty unlikely) are put into fullscreen.
         TaskOrganizer.setLaunchRoot(Display.DEFAULT_DISPLAY, null);
-        tiles.mHomeAndRecentsSurfaces.clear();
         // TODO(task-org): Once task-org is more complete, consider using Appeared/Vanished
         //                 plus specific APIs to clean this up.
         List<ActivityManager.RunningTaskInfo> primaryChildren =