Fix issues with duplicate starting window add requests

There might be cases where we have multiple requests to add a
starting window. To protect against this, we
a) Check for existing startingWindow when adding starting window
b) Don't send the message if we already an add request pending
c) Remove any pending requests when we handle one request

There was already existing logic in place that checked whether
we have a starting window. However, that doesn't cover the case
when requests are pending, but the window hasn't been added yet.

Test: Open settings, open any sub-activity, go home, kill
settings, reopen settings. This generates a duplicate add request
almost guaranteed.
Test: go/wm-smoke
Fixes: 75030092

Change-Id: I5cb7fc0a4e7ab13dce3766be6afe1aa4f85df2e7

diff --git a/services/core/java/com/android/server/wm/AppWindowContainerController.java b/services/core/java/com/android/server/wm/AppWindowContainerController.java
index 1575694..165a409 100644 (file)
--- a/services/core/java/com/android/server/wm/AppWindowContainerController.java
+++ b/services/core/java/com/android/server/wm/AppWindowContainerController.java
@@ -113,63 +113,73 @@ public class AppWindowContainerController
         mListener.onWindowsGone();
     };
 
-    private final Runnable mAddStartingWindow = () -> {
-        final StartingData startingData;
-        final AppWindowToken container;
+    private final Runnable mAddStartingWindow = new Runnable() {
 
-        synchronized (mWindowMap) {
-            if (mContainer == null) {
-                if (DEBUG_STARTING_WINDOW) Slog.v(TAG_WM, "mContainer was null while trying to"
-                        + " add starting window");
-                return;
-            }
-            startingData = mContainer.startingData;
-            container = mContainer;
-        }
+        @Override
+        public void run() {
+            final StartingData startingData;
+            final AppWindowToken container;
+
+            synchronized (mWindowMap) {
+                if (mContainer == null) {
+                    if (DEBUG_STARTING_WINDOW) Slog.v(TAG_WM, "mContainer was null while trying to"
+                            + " add starting window");
+                    return;
+                }
 
-        if (startingData == null) {
-            // Animation has been canceled... do nothing.
-            if (DEBUG_STARTING_WINDOW) Slog.v(TAG_WM, "startingData was nulled out before handling"
-                    + " mAddStartingWindow: " + mContainer);
-            return;
-        }
+                // There can only be one adding request, silly caller!
+                mService.mAnimationHandler.removeCallbacks(this);
 
-        if (DEBUG_STARTING_WINDOW) Slog.v(TAG_WM, "Add starting "
-                + this + ": startingData=" + container.startingData);
+                startingData = mContainer.startingData;
+                container = mContainer;
+            }
 
-        StartingSurface surface = null;
-        try {
-            surface = startingData.createStartingSurface(container);
-        } catch (Exception e) {
-            Slog.w(TAG_WM, "Exception when adding starting window", e);
-        }
-        if (surface != null) {
-            boolean abort = false;
-            synchronized(mWindowMap) {
-                // If the window was successfully added, then
-                // we need to remove it.
-                if (container.removed || container.startingData == null) {
-                    if (DEBUG_STARTING_WINDOW) Slog.v(TAG_WM,
-                            "Aborted starting " + container
-                                    + ": removed=" + container.removed
-                                    + " startingData=" + container.startingData);
-                    container.startingWindow = null;
-                    container.startingData = null;
-                    abort = true;
-                } else {
-                    container.startingSurface = surface;
-                }
-                if (DEBUG_STARTING_WINDOW && !abort) Slog.v(TAG_WM,
-                        "Added starting " + mContainer
-                                + ": startingWindow="
-                                + container.startingWindow + " startingView="
-                                + container.startingSurface);
+            if (startingData == null) {
+                // Animation has been canceled... do nothing.
+                if (DEBUG_STARTING_WINDOW)
+                    Slog.v(TAG_WM, "startingData was nulled out before handling"
+                            + " mAddStartingWindow: " + mContainer);
+                return;
             }
-            if (abort) {
-                surface.remove();
+
+            if (DEBUG_STARTING_WINDOW) Slog.v(TAG_WM, "Add starting "
+                    + AppWindowContainerController.this + ": startingData="
+                    + container.startingData);
+
+            StartingSurface surface = null;
+            try {
+                surface = startingData.createStartingSurface(container);
+            } catch (Exception e) {
+                Slog.w(TAG_WM, "Exception when adding starting window", e);
+            }
+            if (surface != null) {
+                boolean abort = false;
+                synchronized (mWindowMap) {
+                    // If the window was successfully added, then
+                    // we need to remove it.
+                    if (container.removed || container.startingData == null) {
+                        if (DEBUG_STARTING_WINDOW) Slog.v(TAG_WM,
+                                "Aborted starting " + container
+                                        + ": removed=" + container.removed
+                                        + " startingData=" + container.startingData);
+                        container.startingWindow = null;
+                        container.startingData = null;
+                        abort = true;
+                    } else {
+                        container.startingSurface = surface;
+                    }
+                    if (DEBUG_STARTING_WINDOW && !abort) Slog.v(TAG_WM,
+                            "Added starting " + mContainer
+                                    + ": startingWindow="
+                                    + container.startingWindow + " startingView="
+                                    + container.startingSurface);
+                }
+                if (abort) {
+                    surface.remove();
+                }
+            } else if (DEBUG_STARTING_WINDOW) {
+                Slog.v(TAG_WM, "Surface returned was null: " + mContainer);
             }
-        } else if (DEBUG_STARTING_WINDOW) {
-            Slog.v(TAG_WM, "Surface returned was null: " + mContainer);
         }
     };
 
@@ -558,8 +568,10 @@ public class AppWindowContainerController
         // Note: we really want to do sendMessageAtFrontOfQueue() because we
         // want to process the message ASAP, before any other queued
         // messages.
-        if (DEBUG_STARTING_WINDOW) Slog.v(TAG_WM, "Enqueueing ADD_STARTING");
-        mService.mAnimationHandler.postAtFrontOfQueue(mAddStartingWindow);
+        if (!mService.mAnimationHandler.hasCallbacks(mAddStartingWindow)) {
+            if (DEBUG_STARTING_WINDOW) Slog.v(TAG_WM, "Enqueueing ADD_STARTING");
+            mService.mAnimationHandler.postAtFrontOfQueue(mAddStartingWindow);
+        }
     }
 
     private boolean createSnapshot(TaskSnapshot snapshot) {

diff --git a/services/core/java/com/android/server/wm/WindowManagerService.java b/services/core/java/com/android/server/wm/WindowManagerService.java
index bfe8c59..ec6dca3 100644 (file)
--- a/services/core/java/com/android/server/wm/WindowManagerService.java
+++ b/services/core/java/com/android/server/wm/WindowManagerService.java
@@ -1224,6 +1224,10 @@ public class WindowManagerService extends IWindowManager.Stub
                     Slog.w(TAG_WM, "Attempted to add window with exiting application token "
                           + token + ".  Aborting.");
                     return WindowManagerGlobal.ADD_APP_EXITING;
+                } else if (type == TYPE_APPLICATION_STARTING && atoken.startingWindow != null) {
+                    Slog.w(TAG_WM, "Attempted to add starting window to token with already existing"
+                            + " starting window");
+                    return WindowManagerGlobal.ADD_DUPLICATE_ADD;
                 }
             } else if (rootType == TYPE_INPUT_METHOD) {
                 if (token.windowType != TYPE_INPUT_METHOD) {