Move a11y event dispatch back to ui thread.

Test: Ran CTS

Bug: 31753900
Change-Id: I0ba096cb99dd8347a7e9d6c41ff0aa8293dc5d15

3 files changed, 35 insertions, 140 deletions

diff --git a/core/java/android/view/accessibility/AccessibilityManager.java b/core/java/android/view/accessibility/AccessibilityManager.java
index 44f6facd88f5..c125b32f237a 100644
--- a/core/java/android/view/accessibility/AccessibilityManager.java
+++ b/core/java/android/view/accessibility/AccessibilityManager.java
@@ -92,9 +92,6 @@ public final class AccessibilityManager {
     /** @hide */
     public static final int AUTOCLICK_DELAY_DEFAULT = 600;
 
-    /** @hide */
-    public static final int MAX_A11Y_EVENTS_PER_SERVICE_CALL = 20;
-
     static final Object sInstanceSync = new Object();
 
     private static AccessibilityManager sInstance;
@@ -103,8 +100,6 @@ public final class AccessibilityManager {
 
     private IAccessibilityManager mService;
 
-    private EventDispatchThread mEventDispatchThread;
-
     final int mUserId;
 
     final Handler mHandler;
@@ -303,32 +298,44 @@ public final class AccessibilityManager {
      * their descendants.
      */
     public void sendAccessibilityEvent(AccessibilityEvent event) {
-        if (!isEnabled()) {
-            Looper myLooper = Looper.myLooper();
-            if (myLooper == Looper.getMainLooper()) {
-                throw new IllegalStateException(
-                        "Accessibility off. Did you forget to check that?");
-            } else {
-                // If we're not running on the thread with the main looper, it's possible for
-                // the state of accessibility to change between checking isEnabled and
-                // calling this method. So just log the error rather than throwing the
-                // exception.
-                Log.e(LOG_TAG, "AccessibilityEvent sent with accessibility disabled");
+        final IAccessibilityManager service;
+        final int userId;
+        synchronized (mLock) {
+            service = getServiceLocked();
+            if (service == null) {
                 return;
             }
+            if (!mIsEnabled) {
+                Looper myLooper = Looper.myLooper();
+                if (myLooper == Looper.getMainLooper()) {
+                    throw new IllegalStateException(
+                            "Accessibility off. Did you forget to check that?");
+                } else {
+                    // If we're not running on the thread with the main looper, it's possible for
+                    // the state of accessibility to change between checking isEnabled and
+                    // calling this method. So just log the error rather than throwing the
+                    // exception.
+                    Log.e(LOG_TAG, "AccessibilityEvent sent with accessibility disabled");
+                    return;
+                }
+            }
+            userId = mUserId;
         }
-        event.setEventTime(SystemClock.uptimeMillis());
-
-        getEventDispatchThread().scheduleEvent(event);
-    }
-
-    private EventDispatchThread getEventDispatchThread() {
-        synchronized (mLock) {
-            if (mEventDispatchThread == null) {
-                mEventDispatchThread = new EventDispatchThread(mService, mUserId);
-                mEventDispatchThread.start();
+        try {
+            event.setEventTime(SystemClock.uptimeMillis());
+            // it is possible that this manager is in the same process as the service but
+            // client using it is called through Binder from another process. Example: MMS
+            // app adds a SMS notification and the NotificationManagerService calls this method
+            long identityToken = Binder.clearCallingIdentity();
+            service.sendAccessibilityEvent(event, userId);
+            Binder.restoreCallingIdentity(identityToken);
+            if (DEBUG) {
+                Log.i(LOG_TAG, event + " sent");
             }
-            return mEventDispatchThread;
+        } catch (RemoteException re) {
+            Log.e(LOG_TAG, "Error during sending " + event + " ", re);
+        } finally {
+            event.recycle();
         }
     }
 
@@ -713,99 +720,4 @@ public final class AccessibilityManager {
             }
         }
     }
-
-    private static class EventDispatchThread extends Thread {
-        // Second lock used to keep UI thread performant. Never try to grab mLock when holding
-        // this one, or the UI thread will block in send AccessibilityEvent.
-        private final Object mEventQueueLock = new Object();
-
-        // Two lists to hold events. The app thread fills one while we empty the other.
-        private final ArrayList<AccessibilityEvent> mEventLists0 =
-                new ArrayList<>(MAX_A11Y_EVENTS_PER_SERVICE_CALL);
-        private final ArrayList<AccessibilityEvent> mEventLists1 =
-                new ArrayList<>(MAX_A11Y_EVENTS_PER_SERVICE_CALL);
-
-        private boolean mPingPongListToggle;
-
-        private final IAccessibilityManager mService;
-
-        private final int mUserId;
-
-        EventDispatchThread(IAccessibilityManager service, int userId) {
-            mService = service;
-            mUserId = userId;
-        }
-
-        @Override
-        public void run() {
-            while (true) {
-                ArrayList<AccessibilityEvent> listBeingDrained;
-                synchronized (mEventQueueLock) {
-                    ArrayList<AccessibilityEvent> listBeingFilled = getListBeingFilledLocked();
-                    if (listBeingFilled.isEmpty()) {
-                        try {
-                            mEventQueueLock.wait();
-                        } catch (InterruptedException e) {
-                            // Treat as a notify
-                        }
-                    }
-                    // Swap buffers
-                    mPingPongListToggle = !mPingPongListToggle;
-                    listBeingDrained = listBeingFilled;
-                }
-                dispatchEvents(listBeingDrained);
-            }
-        }
-
-        public void scheduleEvent(AccessibilityEvent event) {
-            synchronized (mEventQueueLock) {
-                getListBeingFilledLocked().add(event);
-                mEventQueueLock.notifyAll();
-            }
-        }
-
-        private ArrayList<AccessibilityEvent> getListBeingFilledLocked() {
-            return (mPingPongListToggle) ? mEventLists0 : mEventLists1;
-        }
-
-        private void dispatchEvents(ArrayList<AccessibilityEvent> events) {
-            int eventListCapacityLowerBound = events.size();
-            while (events.size() > 0) {
-                // We don't want to consume extra memory if an app sends a lot of events in a
-                // one-off event. Cap the list length at double the max events per call.
-                // We'll end up with extra GC for apps that send huge numbers of events, but
-                // sending that many events will lead to bad performance in any case.
-                if ((eventListCapacityLowerBound > 2 * MAX_A11Y_EVENTS_PER_SERVICE_CALL)
-                        && (events.size() <= 2 * MAX_A11Y_EVENTS_PER_SERVICE_CALL)) {
-                    events.trimToSize();
-                    eventListCapacityLowerBound = events.size();
-                }
-                // We only expect this loop to run once, as the app shouldn't be sending
-                // huge numbers of events.
-                // The clear in the called method will remove the sent events
-                dispatchOneBatchOfEvents(events.subList(0,
-                        Math.min(events.size(), MAX_A11Y_EVENTS_PER_SERVICE_CALL)));
-            }
-        }
-
-        private void dispatchOneBatchOfEvents(List<AccessibilityEvent> events) {
-            if (events.isEmpty()) {
-                return;
-            }
-            long identityToken = Binder.clearCallingIdentity();
-            try {
-                mService.sendAccessibilityEvents(new ParceledListSlice<>(events),
-                        mUserId);
-            } catch (RemoteException re) {
-                Log.e(LOG_TAG, "Error sending multiple events");
-            }
-            Binder.restoreCallingIdentity(identityToken);
-            if (DEBUG) {
-                Log.i(LOG_TAG, events.size() + " events sent");
-            }
-            for (int i = events.size() - 1; i >= 0; i--) {
-                events.remove(i).recycle();
-            }
-        }
-    }
 }
diff --git a/core/java/android/view/accessibility/IAccessibilityManager.aidl b/core/java/android/view/accessibility/IAccessibilityManager.aidl
index aa9cb39062f9..71e77c417ec3 100644
--- a/core/java/android/view/accessibility/IAccessibilityManager.aidl
+++ b/core/java/android/view/accessibility/IAccessibilityManager.aidl
@@ -21,7 +21,6 @@ import android.accessibilityservice.AccessibilityServiceInfo;
 import android.accessibilityservice.IAccessibilityServiceConnection;
 import android.accessibilityservice.IAccessibilityServiceClient;
 import android.content.ComponentName;
-import android.content.pm.ParceledListSlice;
 import android.view.accessibility.AccessibilityEvent;
 import android.view.accessibility.AccessibilityNodeInfo;
 import android.view.accessibility.IAccessibilityInteractionConnection;
@@ -30,7 +29,7 @@ import android.view.IWindow;
 
 /**
  * Interface implemented by the AccessibilityManagerService called by
- * the AccessibilityMasngers.
+ * the AccessibilityManagers.
  *
  * @hide
  */
@@ -40,8 +39,6 @@ interface IAccessibilityManager {
 
     void sendAccessibilityEvent(in AccessibilityEvent uiEvent, int userId);
 
-    void sendAccessibilityEvents(in ParceledListSlice events, int userId);
-
     List<AccessibilityServiceInfo> getInstalledAccessibilityServiceList(int userId);
 
     List<AccessibilityServiceInfo> getEnabledAccessibilityServiceList(int feedbackType, int userId);
diff --git a/services/accessibility/java/com/android/server/accessibility/AccessibilityManagerService.java b/services/accessibility/java/com/android/server/accessibility/AccessibilityManagerService.java
index 0b83e66febba..54c9afea5766 100644
--- a/services/accessibility/java/com/android/server/accessibility/AccessibilityManagerService.java
+++ b/services/accessibility/java/com/android/server/accessibility/AccessibilityManagerService.java
@@ -498,20 +498,6 @@ public class AccessibilityManagerService extends IAccessibilityManager.Stub {
     }
 
     @Override
-    public void sendAccessibilityEvents(ParceledListSlice events, int userId) {
-        List<AccessibilityEvent> a11yEvents = events.getList();
-        // Grab the lock once for the entire batch
-        synchronized (mLock) {
-            int numEventsToProcess = Math.min(a11yEvents.size(),
-                    AccessibilityManager.MAX_A11Y_EVENTS_PER_SERVICE_CALL);
-            for (int i = 0; i < numEventsToProcess; i++) {
-                AccessibilityEvent event = a11yEvents.get(i);
-                sendAccessibilityEvent(event, userId);
-            }
-        }
-    }
-
-    @Override
     public List<AccessibilityServiceInfo> getInstalledAccessibilityServiceList(int userId) {
         synchronized (mLock) {
             // We treat calls from a profile as if made by its parent as profiles