Ensure surfaces stay alive until activity stop.

am: e12aece4ca

* commit 'e12aece4cad849efbbe6a806f132613a56699230':
  Ensure surfaces stay alive until activity stop.

core/java/android/view/IWindowManager.aidl

@@ -166,6 +166,7 @@ interface IWindowManager
             in CompatibilityInfo compatInfo, CharSequence nonLocalizedLabel, int labelRes,
             int icon, int logo, int windowFlags, IBinder transferFrom, boolean createIfNeeded);
     void setAppVisibility(IBinder token, boolean visible);
+    void notifyAppStopped(IBinder token);
     void startAppFreezingScreen(IBinder token, int configChanges);
     void stopAppFreezingScreen(IBinder token, boolean force);
     void removeAppToken(IBinder token);

services/core/java/com/android/server/am/ActivityStack.java

@@ -1097,6 +1097,9 @@ final class ActivityStack {
             mHandler.removeMessages(STOP_TIMEOUT_MSG, r);
             r.stopped = true;
             r.state = ActivityState.STOPPED;
+
+            mWindowManager.notifyAppStopped(r.appToken);
+
             if (getVisibleBehindActivity() == r) {
                 mStackSupervisor.requestVisibleBehindLocked(r, false);
             }

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

@@ -127,6 +127,8 @@ class AppWindowToken extends WindowToken {
 
     boolean mAlwaysFocusable;
 
+    boolean mAppStopped;
+
     ArrayDeque<Rect> mFrozenBounds = new ArrayDeque<>();
 
     AppWindowToken(WindowManagerService _service, IApplicationToken _token,
@@ -311,6 +313,47 @@ class AppWindowToken extends WindowToken {
         }
     }
 
+    // Here we destroy surfaces which have been marked as eligible by the animator, taking care
+    // to ensure the client has finished with them. If the client could still be using them
+    // we will skip destruction and try again when the client has stopped.
+    void destroySurfaces() {
+        final ArrayList<WindowState> allWindows = (ArrayList<WindowState>) allAppWindows.clone();
+        final DisplayContentList displayList = new DisplayContentList();
+        for (int i = allWindows.size() - 1; i >= 0; i--) {
+            final WindowState win = allWindows.get(i);
+            if (!win.mDestroying) {
+                continue;
+            }
+
+            if (!mAppStopped && !win.mClientRemoveRequested) {
+                return;
+            }
+
+            win.destroyOrSaveSurface();
+            if (win.mRemoveOnExit) {
+                win.mExiting = false;
+                service.removeWindowInnerLocked(win);
+            }
+            final DisplayContent displayContent = win.getDisplayContent();
+            if (displayContent != null && !displayList.contains(displayContent)) {
+                displayList.add(displayContent);
+            }
+            win.mDestroying = false;
+        }
+        for (int i = 0; i < displayList.size(); i++) {
+            final DisplayContent displayContent = displayList.get(i);
+            service.mLayersController.assignLayersLocked(displayContent.getWindowList());
+            displayContent.layoutNeeded = true;
+        }
+    }
+
+    // The application has stopped, so destroy any surfaces which were keeping alive
+    // in case they were still being used.
+    void notifyAppStopped() {
+        mAppStopped = true;
+        destroySurfaces();
+    }
+
     /**
      * Checks whether we should save surfaces for this app.
      *

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

@@ -2154,6 +2154,14 @@ public class WindowManagerService extends IWindowManager.Stub
             if (win == null) {
                 return;
             }
+            // We set this here instead of removeWindowLocked because we only want it to be
+            // true when the client has requested we remove the window. In other remove
+            // cases, we have to wait for activity stop to safely remove the window (as the
+            // client may still be using the surface). In this case though, the client has
+            // just dismissed a window (for example a Dialog) and activity stop isn't
+            // necessarily imminent, so we need to know not to wait for it after our
+            // hanimation (if applicable) finishes.
+            win.mClientRemoveRequested = true;
             removeWindowLocked(win);
         }
     }
@@ -4187,6 +4195,24 @@ public class WindowManagerService extends IWindowManager.Stub
         }
     }
 
+    @Override
+    public void notifyAppStopped(IBinder token) {
+        if (!checkCallingPermission(android.Manifest.permission.MANAGE_APP_TOKENS,
+                "notifyAppStopped()")) {
+            throw new SecurityException("Requires MANAGE_APP_TOKENS permission");
+        }
+
+        synchronized(mWindowMap) {
+            final AppWindowToken wtoken;
+            wtoken = findAppWindowToken(token);
+            if (wtoken == null) {
+                Slog.w(TAG_WM, "Attempted to set visibility of non-existing app token: " + token);
+                return;
+            }
+            wtoken.notifyAppStopped();
+        }
+    }
+
     @Override
     public void setAppVisibility(IBinder token, boolean visible) {
         if (!checkCallingPermission(android.Manifest.permission.MANAGE_APP_TOKENS,
@@ -4210,6 +4236,7 @@ public class WindowManagerService extends IWindowManager.Stub
 
             mOpeningApps.remove(wtoken);
             mClosingApps.remove(wtoken);
+            wtoken.mAppStopped = false;
             wtoken.waitingToShow = false;
             wtoken.hiddenRequested = !visible;
 

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

@@ -385,6 +385,13 @@ final class WindowState implements WindowManagerPolicy.WindowState {
     /** Is this window now (or just being) removed? */
     boolean mRemoved;
 
+    /**
+     * Has the client requested we remove the window? In this case we know
+     * that we can dispose of it when we wish without further synchronization
+     * with the client
+     */
+    boolean mClientRemoveRequested;
+
     /**
      * Temp for keeping track of windows that have been removed when
      * rebuilding window list.

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

@@ -471,16 +471,31 @@ class WindowStateAnimator {
         if (WindowManagerService.localLOGV) Slog.v(
                 TAG, "Exit animation finished in " + this
                 + ": remove=" + mWin.mRemoveOnExit);
-        if (hasSurface()) {
-            mService.mDestroySurface.add(mWin);
-            mWin.mDestroying = true;
-            hide("finishExit");
-        }
-        mWin.mExiting = false;
-        if (mWin.mRemoveOnExit) {
-            mService.mPendingRemove.add(mWin);
-            mWin.mRemoveOnExit = false;
+
+
+        mWin.mDestroying = true;
+
+        // If we have an app token, we ask it to destroy the surface for us,
+        // so that it can take care to ensure the activity has actually stopped
+        // and the surface is not still in use. Otherwise we add the service to
+        // mDestroySurface and allow it to be processed in our next transaction.
+        if (mWin.mAppToken != null) {
+            if (hasSurface()) {
+                hide("finishExit");
+            }
+            mWin.mAppToken.destroySurfaces();
+        } else {
+            if (hasSurface()) {
+                mService.mDestroySurface.add(mWin);
+                hide("finishExit");
+            }
+            mWin.mExiting = false;
+            if (mWin.mRemoveOnExit) {
+                mService.mPendingRemove.add(mWin);
+                mWin.mRemoveOnExit = false;
+            }
         }
+
         mWallpaperControllerLocked.hideWallpapers(mWin);
     }
 

tools/layoutlib/bridge/src/android/view/IWindowManagerImpl.java

@@ -347,6 +347,11 @@ public class IWindowManagerImpl implements IWindowManager {
 
     }
 
+    @Override
+    public void notifyAppStopped(IBinder token) throws RemoteException {
+        // TODO Auto-generated method stub
+    }
+
     @Override
     public void setEventDispatching(boolean arg0) throws RemoteException {
         // TODO Auto-generated method stub