Merge "Reduce cost of a11y services with magnification." into nyc-dev

core/java/android/accessibilityservice/AccessibilityService.java

@@ -949,7 +949,7 @@ public abstract class AccessibilityService extends Service {
                             mService.mConnectionId);
             if (connection != null) {
                 try {
-                    return connection.getMagnifiedRegion();
+                    return connection.getMagnificationRegion();
                 } catch (RemoteException re) {
                     Log.w(LOG_TAG, "Failed to obtain magnified region", re);
                     re.rethrowFromSystemServer();

core/java/android/accessibilityservice/IAccessibilityServiceConnection.aidl

@@ -75,7 +75,7 @@ interface IAccessibilityServiceConnection {
 
     float getMagnificationCenterY();
 
-    Region getMagnifiedRegion();
+    Region getMagnificationRegion();
 
     boolean resetMagnification(boolean animate);
 

services/accessibility/java/com/android/server/accessibility/AccessibilityManagerService.java

@@ -1737,7 +1737,7 @@ public class AccessibilityManagerService extends IAccessibilityManager.Stub {
         }
 
         if (userState.mIsDisplayMagnificationEnabled ||
-                userHasMagnificationServicesLocked(userState)) {
+                userHasListeningMagnificationServicesLocked(userState)) {
             // Initialize the magnification controller if necessary
             getMagnificationController();
             mMagnificationController.register();
@@ -1761,6 +1761,22 @@ public class AccessibilityManagerService extends IAccessibilityManager.Stub {
         return false;
     }
 
+    /**
+     * Returns whether the specified user has any services that are capable of
+     * controlling magnification and are actively listening for magnification updates.
+     */
+    private boolean userHasListeningMagnificationServicesLocked(UserState userState) {
+        final List<Service> services = userState.mBoundServices;
+        for (int i = 0, count = services.size(); i < count; i++) {
+            final Service service = services.get(i);
+            if (mSecurityPolicy.canControlMagnification(service)
+                    && service.mInvocationHandler.mIsMagnificationCallbackEnabled) {
+                return true;
+            }
+        }
+        return false;
+    }
+
     private void updateSoftKeyboardShowModeLocked(UserState userState) {
         final int userId = userState.mUserId;
         // Only check whether we need to reset the soft keyboard mode if it is not set to the
@@ -2864,19 +2880,28 @@ public class AccessibilityManagerService extends IAccessibilityManager.Stub {
         }
 
         @Override
-        public Region getMagnifiedRegion() {
+        public Region getMagnificationRegion() {
             synchronized (mLock) {
-                if (!isCalledForCurrentUserLocked()) {
-                    return Region.obtain();
-                }
-            }
-            final long identity = Binder.clearCallingIdentity();
-            try {
                 final Region region = Region.obtain();
-                getMagnificationController().getMagnificationRegion(region);
-                return region;
-            } finally {
-                Binder.restoreCallingIdentity(identity);
+                if (!isCalledForCurrentUserLocked()) {
+                    return region;
+                }
+                MagnificationController magnificationController = getMagnificationController();
+                boolean forceRegistration = mSecurityPolicy.canControlMagnification(this);
+                boolean initiallyRegistered = magnificationController.isRegisteredLocked();
+                if (!initiallyRegistered && forceRegistration) {
+                    magnificationController.register();
+                }
+                final long identity = Binder.clearCallingIdentity();
+                try {
+                    magnificationController.getMagnificationRegion(region);
+                    return region;
+                } finally {
+                    Binder.restoreCallingIdentity(identity);
+                    if (!initiallyRegistered && forceRegistration) {
+                        magnificationController.unregister();
+                    }
+                }
             }
         }
 
@@ -2940,13 +2965,17 @@ public class AccessibilityManagerService extends IAccessibilityManager.Stub {
                 if (!permissionGranted) {
                     return false;
                 }
-            }
-            final long identity = Binder.clearCallingIdentity();
-            try {
-                return getMagnificationController().setScaleAndCenter(
-                        scale, centerX, centerY, animate, mId);
-            } finally {
-                Binder.restoreCallingIdentity(identity);
+                final long identity = Binder.clearCallingIdentity();
+                try {
+                    MagnificationController magnificationController = getMagnificationController();
+                    if (!magnificationController.isRegisteredLocked()) {
+                        magnificationController.register();
+                    }
+                    return magnificationController
+                            .setScaleAndCenter(scale, centerX, centerY, animate, mId);
+                } finally {
+                    Binder.restoreCallingIdentity(identity);
+                }
             }
         }
 

services/accessibility/java/com/android/server/accessibility/MagnificationController.java

@@ -151,6 +151,15 @@ class MagnificationController {
         }
     }
 
+    /**
+     * Check if we are registered. Note that we may be planning to unregister at any moment.
+     *
+     * @return {@code true} if the controller is registered. {@code false} otherwise.
+     */
+    public boolean isRegisteredLocked() {
+        return mRegistered;
+    }
+
     private void unregisterInternalLocked() {
         if (mRegistered) {
             mSpecAnimationBridge.setEnabled(false);
@@ -179,6 +188,10 @@ class MagnificationController {
      */
     private void onMagnificationRegionChanged(Region magnified, boolean updateSpec) {
         synchronized (mLock) {
+            if (!mRegistered) {
+                // Don't update if we've unregistered
+                return;
+            }
             boolean magnificationChanged = false;
             boolean boundsChanged = false;