Fixing memory leaks in the accessiiblity layer.

1. AccessibilityInteractionConnections were removed from the
   AccessiiblityManagerService but their DeathRecipents were
   not unregistered, thus every removed interaction connection
   was essentially leaking. Such connection is registered in
   the system for every ViewRootImpl when accessiiblity is
   enabled and inregistered when disabled.

2. Every AccessibilityEvent and AccessiilbityEventInfo obtained
   from a widnow content querying accessibility service had a
   handle to a binder proxy over which to make queries. Hoewever,
   holding a proxy to a remote binder prevents the latter from
   being garbage collected. Therefore, now the events and infos
   have a connection id insteand and the hindden singleton
   AccessiiblityInteaction client via which queries are made
   has a registry with the connections. This class looks up
   the connection given its id before making an IPC. Now the
   connection is stored in one place and when an accessibility
   service is disconnected the system sets the connection to
   null so the binder object in the system process can be GCed.
   Note that before this change a bad implemented accessibility
   service could cache events or infos causing a leak in the
   system process. This should never happen.

3. SparseArray was not clearing the reference to the last moved
   element while garbage collecting thus causing a leak.

bug:5664337

Change-Id: Id397f614b026d43bd7b57bb7f8186bca5cdfcff9

1 files changed, 83 insertions, 115 deletions

diff --git a/core/tests/coretests/src/android/accessibilityservice/InterrogationActivityTest.java b/core/tests/coretests/src/android/accessibilityservice/InterrogationActivityTest.java
index 3521296..ec12124 100644
--- a/core/tests/coretests/src/android/accessibilityservice/InterrogationActivityTest.java
+++ b/core/tests/coretests/src/android/accessibilityservice/InterrogationActivityTest.java
@@ -26,6 +26,7 @@ import android.os.SystemClock;
 import android.test.ActivityInstrumentationTestCase2;
 import android.test.suitebuilder.annotation.LargeTest;
 import android.util.Log;
+import android.view.View;
 import android.view.accessibility.AccessibilityEvent;
 import android.view.accessibility.AccessibilityInteractionClient;
 import android.view.accessibility.AccessibilityManager;
@@ -54,28 +55,31 @@ public class InterrogationActivityTest
     // Timeout before give up wait for the system to process an accessibility setting change.       
     private static final int TIMEOUT_PROPAGATE_ACCESSIBLITY_SETTING = 2000;
 
+    // Timeout for the accessibility state of an Activity to be fully initialized.
+    private static final int TIMEOUT_ACCESSIBLITY_STATE_INITIALIZED_MILLIS = 100;
+
     // Handle to a connection to the AccessibilityManagerService
-    private static IAccessibilityServiceConnection sConnection;
+    private static int sConnectionId = View.NO_ID;
 
     // The last received accessibility event
-    private static volatile AccessibilityEvent sLastFocusAccessibilityEvent;
+    private volatile AccessibilityEvent mLastAccessibilityEvent;
 
     public InterrogationActivityTest() {
         super(InterrogationActivity.class);
     }
 
+    @Override
+    public void setUp() throws Exception {
+        ensureConnection();
+        bringUpActivityWithInitalizedAccessbility();
+    }
+
     @LargeTest
     public void testFindAccessibilityNodeInfoByViewId() throws Exception {
         final long startTimeMillis = SystemClock.uptimeMillis();
         try {
-            // hook into the system first
-            IAccessibilityServiceConnection connection = getConnection();
-
-            // bring up the activity
-            getActivity();
-
             AccessibilityNodeInfo button = AccessibilityInteractionClient.getInstance()
-                .findAccessibilityNodeInfoByViewIdInActiveWindow(connection, R.id.button5);
+                .findAccessibilityNodeInfoByViewIdInActiveWindow(sConnectionId, R.id.button5);
             assertNotNull(button);
             assertEquals(0, button.getChildCount());
 
@@ -120,15 +124,9 @@ public class InterrogationActivityTest
     public void testFindAccessibilityNodeInfoByViewText() throws Exception {
         final long startTimeMillis = SystemClock.uptimeMillis();
         try {
-            // hook into the system first
-            IAccessibilityServiceConnection connection = getConnection();
-
-            // bring up the activity
-            getActivity();
-
             // find a view by text
-            List<AccessibilityNodeInfo> buttons =  AccessibilityInteractionClient.getInstance()
-                .findAccessibilityNodeInfosByViewTextInActiveWindow(connection, "butto");
+            List<AccessibilityNodeInfo> buttons = AccessibilityInteractionClient.getInstance()
+                .findAccessibilityNodeInfosByViewTextInActiveWindow(sConnectionId, "butto");
             assertEquals(9, buttons.size());
         } finally {
             if (DEBUG) {
@@ -143,15 +141,11 @@ public class InterrogationActivityTest
     public void testFindAccessibilityNodeInfoByViewTextContentDescription() throws Exception {
         final long startTimeMillis = SystemClock.uptimeMillis();
         try {
-            // hook into the system first
-            IAccessibilityServiceConnection connection = getConnection();
-
-            // bring up the activity
-            getActivity();
+            bringUpActivityWithInitalizedAccessbility();
 
             // find a view by text
-            List<AccessibilityNodeInfo> buttons =  AccessibilityInteractionClient.getInstance()
-                .findAccessibilityNodeInfosByViewTextInActiveWindow(connection,
+            List<AccessibilityNodeInfo> buttons = AccessibilityInteractionClient.getInstance()
+                .findAccessibilityNodeInfosByViewTextInActiveWindow(sConnectionId,
                         "contentDescription");
             assertEquals(1, buttons.size());
         } finally {
@@ -167,12 +161,6 @@ public class InterrogationActivityTest
     public void testTraverseAllViews() throws Exception {
         final long startTimeMillis = SystemClock.uptimeMillis();
         try {
-            // hook into the system first
-            IAccessibilityServiceConnection connection = getConnection();
-
-            // bring up the activity
-            getActivity();
-
             // make list of expected nodes
             List<String> classNameAndTextList = new ArrayList<String>();
             classNameAndTextList.add("android.widget.LinearLayout");
@@ -190,7 +178,7 @@ public class InterrogationActivityTest
             classNameAndTextList.add("android.widget.ButtonButton9");
 
             AccessibilityNodeInfo root = AccessibilityInteractionClient.getInstance()
-                .findAccessibilityNodeInfoByViewIdInActiveWindow(connection, R.id.root);
+                .findAccessibilityNodeInfoByViewIdInActiveWindow(sConnectionId, R.id.root);
             assertNotNull("We must find the existing root.", root);
 
             Queue<AccessibilityNodeInfo> fringe = new LinkedList<AccessibilityNodeInfo>();
@@ -227,23 +215,17 @@ public class InterrogationActivityTest
     public void testPerformAccessibilityActionFocus() throws Exception {
         final long startTimeMillis = SystemClock.uptimeMillis();
         try {
-            // hook into the system first
-            IAccessibilityServiceConnection connection = getConnection();
-
-            // bring up the activity
-            getActivity();
-
             // find a view and make sure it is not focused
             AccessibilityNodeInfo button = AccessibilityInteractionClient.getInstance()
-                .findAccessibilityNodeInfoByViewIdInActiveWindow(connection, R.id.button5);
+                .findAccessibilityNodeInfoByViewIdInActiveWindow(sConnectionId, R.id.button5);
             assertFalse(button.isFocused());
 
             // focus the view
             assertTrue(button.performAction(ACTION_FOCUS));
 
             // find the view again and make sure it is focused
-            button =  AccessibilityInteractionClient.getInstance()
-                .findAccessibilityNodeInfoByViewIdInActiveWindow(connection, R.id.button5);
+            button = AccessibilityInteractionClient.getInstance()
+                .findAccessibilityNodeInfoByViewIdInActiveWindow(sConnectionId, R.id.button5);
             assertTrue(button.isFocused());
         } finally {
             if (DEBUG) {
@@ -257,15 +239,9 @@ public class InterrogationActivityTest
     public void testPerformAccessibilityActionClearFocus() throws Exception {
         final long startTimeMillis = SystemClock.uptimeMillis();
         try {
-            // hook into the system first
-            IAccessibilityServiceConnection connection = getConnection();
-
-            // bring up the activity
-            getActivity();
-
             // find a view and make sure it is not focused
             AccessibilityNodeInfo button = AccessibilityInteractionClient.getInstance()
-                .findAccessibilityNodeInfoByViewIdInActiveWindow(connection, R.id.button5);
+                .findAccessibilityNodeInfoByViewIdInActiveWindow(sConnectionId, R.id.button5);
             assertFalse(button.isFocused());
 
             // focus the view
@@ -273,7 +249,7 @@ public class InterrogationActivityTest
 
             // find the view again and make sure it is focused
             button = AccessibilityInteractionClient.getInstance()
-                .findAccessibilityNodeInfoByViewIdInActiveWindow(connection, R.id.button5);
+                .findAccessibilityNodeInfoByViewIdInActiveWindow(sConnectionId, R.id.button5);
             assertTrue(button.isFocused());
 
             // unfocus the view
@@ -281,7 +257,7 @@ public class InterrogationActivityTest
 
             // find the view again and make sure it is not focused
             button = AccessibilityInteractionClient.getInstance()
-                .findAccessibilityNodeInfoByViewIdInActiveWindow(connection, R.id.button5);
+                .findAccessibilityNodeInfoByViewIdInActiveWindow(sConnectionId, R.id.button5);
             assertFalse(button.isFocused());
         } finally {
             if (DEBUG) {
@@ -296,15 +272,9 @@ public class InterrogationActivityTest
     public void testPerformAccessibilityActionSelect() throws Exception {
         final long startTimeMillis = SystemClock.uptimeMillis();
         try {
-            // hook into the system first
-            IAccessibilityServiceConnection connection = getConnection();
-
-            // bring up the activity
-            getActivity();
-
             // find a view and make sure it is not selected
             AccessibilityNodeInfo button = AccessibilityInteractionClient.getInstance()
-                .findAccessibilityNodeInfoByViewIdInActiveWindow(connection, R.id.button5);
+                .findAccessibilityNodeInfoByViewIdInActiveWindow(sConnectionId, R.id.button5);
             assertFalse(button.isSelected());
 
             // select the view
@@ -312,7 +282,7 @@ public class InterrogationActivityTest
 
             // find the view again and make sure it is selected
             button = AccessibilityInteractionClient.getInstance()
-                .findAccessibilityNodeInfoByViewIdInActiveWindow(connection, R.id.button5);
+                .findAccessibilityNodeInfoByViewIdInActiveWindow(sConnectionId, R.id.button5);
             assertTrue(button.isSelected());
         } finally {
             if (DEBUG) {
@@ -326,15 +296,9 @@ public class InterrogationActivityTest
     public void testPerformAccessibilityActionClearSelection() throws Exception {
         final long startTimeMillis = SystemClock.uptimeMillis();
         try {
-            // hook into the system first
-            IAccessibilityServiceConnection connection = getConnection();
-
-            // bring up the activity
-            getActivity();
-
             // find a view and make sure it is not selected
             AccessibilityNodeInfo button = AccessibilityInteractionClient.getInstance()
-                .findAccessibilityNodeInfoByViewIdInActiveWindow(connection, R.id.button5);
+                .findAccessibilityNodeInfoByViewIdInActiveWindow(sConnectionId, R.id.button5);
             assertFalse(button.isSelected());
 
             // select the view
@@ -342,15 +306,15 @@ public class InterrogationActivityTest
 
             // find the view again and make sure it is selected
             button = AccessibilityInteractionClient.getInstance()
-                .findAccessibilityNodeInfoByViewIdInActiveWindow(connection, R.id.button5);
+                .findAccessibilityNodeInfoByViewIdInActiveWindow(sConnectionId, R.id.button5);
             assertTrue(button.isSelected());
 
             // unselect the view
             assertTrue(button.performAction(ACTION_CLEAR_SELECTION));
 
             // find the view again and make sure it is not selected
-            button =  AccessibilityInteractionClient.getInstance()
-                .findAccessibilityNodeInfoByViewIdInActiveWindow(connection, R.id.button5);
+            button = AccessibilityInteractionClient.getInstance()
+                .findAccessibilityNodeInfoByViewIdInActiveWindow(sConnectionId, R.id.button5);
             assertFalse(button.isSelected());
         } finally {
             if (DEBUG) {
@@ -365,30 +329,24 @@ public class InterrogationActivityTest
     public void testAccessibilityEventGetSource() throws Exception {
         final long startTimeMillis = SystemClock.uptimeMillis();
         try {
-            // hook into the system first
-            IAccessibilityServiceConnection connection = getConnection();
-
-            // bring up the activity
-            getActivity();  
-
             // find a view and make sure it is not focused
             AccessibilityNodeInfo button = AccessibilityInteractionClient.getInstance()
-                .findAccessibilityNodeInfoByViewIdInActiveWindow(connection, R.id.button5);
+                .findAccessibilityNodeInfoByViewIdInActiveWindow(sConnectionId, R.id.button5);
             assertFalse(button.isSelected());
 
             // focus the view
             assertTrue(button.performAction(ACTION_FOCUS));
 
-            synchronized (sConnection) {
+            synchronized (this) {
                 try {
-                    sConnection.wait(500);
+                    wait(TIMEOUT_ACCESSIBLITY_STATE_INITIALIZED_MILLIS);
                 } catch (InterruptedException ie) {
                     /* ignore */
                 }
             }
 
             // check that last event source
-            AccessibilityNodeInfo source = sLastFocusAccessibilityEvent.getSource();
+            AccessibilityNodeInfo source = mLastAccessibilityEvent.getSource();
             assertNotNull(source);
 
             // bounds
@@ -430,15 +388,9 @@ public class InterrogationActivityTest
     public void testObjectContract() throws Exception {
         final long startTimeMillis = SystemClock.uptimeMillis();
         try {
-            // hook into the system first
-            IAccessibilityServiceConnection connection = getConnection();
-
-            // bring up the activity
-            getActivity();
-
             // find a view and make sure it is not focused
             AccessibilityNodeInfo button = AccessibilityInteractionClient.getInstance()
-                .findAccessibilityNodeInfoByViewIdInActiveWindow(connection, R.id.button5);
+                .findAccessibilityNodeInfoByViewIdInActiveWindow(sConnectionId, R.id.button5);
             AccessibilityNodeInfo parent = button.getParent();
             final int childCount = parent.getChildCount();
             for (int i = 0; i < childCount; i++) {
@@ -459,24 +411,57 @@ public class InterrogationActivityTest
         }
     }
 
-    @Override
-    protected void scrubClass(Class<?> testCaseClass) {
-        /* intentionally do not scrub */
+    private void bringUpActivityWithInitalizedAccessbility() {
+        mLastAccessibilityEvent = null;
+        // bring up the activity
+        getActivity();
+
+        final long startTimeMillis = SystemClock.uptimeMillis();
+        while (true) {
+            if (mLastAccessibilityEvent != null) {
+                final int eventType = mLastAccessibilityEvent.getEventType();
+                if (eventType == AccessibilityEvent.TYPE_WINDOW_STATE_CHANGED) {
+                    return;
+                }
+            }
+            final long remainingTimeMillis = TIMEOUT_ACCESSIBLITY_STATE_INITIALIZED_MILLIS
+                    - (SystemClock.uptimeMillis() - startTimeMillis);
+            if (remainingTimeMillis <= 0) {
+                return;
+            }
+            synchronized (this) {
+                try {
+                    wait(remainingTimeMillis);
+                } catch (InterruptedException e) {
+                    /* ignore */
+                }
+            }
+        }
     }
 
-    private IAccessibilityServiceConnection getConnection() throws Exception {
-        if (sConnection == null) {
+    private void ensureConnection() throws Exception {
+        if (sConnectionId == View.NO_ID) {
             IEventListener listener = new IEventListener.Stub() {
-                public void setConnection(IAccessibilityServiceConnection connection) {}
+                public void setConnection(IAccessibilityServiceConnection connection,
+                        int connectionId) {
+                    sConnectionId = connectionId;
+                    if (connection != null) {
+                        AccessibilityInteractionClient.getInstance().addConnection(connectionId,
+                                connection);
+                    } else {
+                        AccessibilityInteractionClient.getInstance().removeConnection(connectionId);
+                    }
+                    synchronized (this) {
+                        notifyAll();
+                    }
+                }
 
                 public void onInterrupt() {}
 
                 public void onAccessibilityEvent(AccessibilityEvent event) {
-                    if (event.getEventType() == AccessibilityEvent.TYPE_VIEW_FOCUSED) {
-                        sLastFocusAccessibilityEvent = AccessibilityEvent.obtain(event);
-                    }
-                    synchronized (sConnection) {
-                        sConnection.notifyAll();
+                    mLastAccessibilityEvent = AccessibilityEvent.obtain(event);
+                    synchronized (this) {
+                        notifyAll();
                     }
                 }
             };
@@ -485,28 +470,11 @@ public class InterrogationActivityTest
                 AccessibilityManager.getInstance(getInstrumentation().getContext());
 
             synchronized (this) {
-                if (!accessibilityManager.isEnabled()) {
-                    // Make sure we wake ourselves as the desired state is propagated.
-                    accessibilityManager.addAccessibilityStateChangeListener(
-                            new AccessibilityManager.AccessibilityStateChangeListener() {
-                                public void onAccessibilityStateChanged(boolean enabled) {
-                                    synchronized (this) {
-                                        notifyAll();
-                                    }
-                                }
-                            });
-                    IAccessibilityManager manager = IAccessibilityManager.Stub.asInterface(
+                IAccessibilityManager manager = IAccessibilityManager.Stub.asInterface(
                         ServiceManager.getService(Context.ACCESSIBILITY_SERVICE));
-                    sConnection = manager.registerEventListener(listener);
-
-                    wait(TIMEOUT_PROPAGATE_ACCESSIBLITY_SETTING);
-                } else {
-                    IAccessibilityManager manager = IAccessibilityManager.Stub.asInterface(
-                          ServiceManager.getService(Context.ACCESSIBILITY_SERVICE));
-                    sConnection = manager.registerEventListener(listener);
-                }
+                manager.registerEventListener(listener);
+                wait(TIMEOUT_PROPAGATE_ACCESSIBLITY_SETTING);
             }
         }
-        return sConnection;
     }
 }