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Commit 2fbdd486 authored by Phil Weaver's avatar Phil Weaver
Browse files

Reduce cost of a11y services with magnification. 

Services that declare that they can control magnification,
but never actually make a change or register a listener
waste cycles as we compute magnification data they never use.

Avoid registering for magnification callbacks unless magnification
gestures are enabled, a service is listening for magnification
changes, or a service has changed magnification.

Bug: 28425922
Change-Id: I114a833669bd53b2cd757c94ea52b65a2f838a08
parent 5ee41098

core/java/android/accessibilityservice/AccessibilityService.java

+1 −1
Original line number Diff line number Diff line
@@ -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

+1 −1
Original line number Diff line number Diff line
@@ -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

+47 −18
Original line number Diff line number Diff line
@@ -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) {

                final Region region = Region.obtain();

                if (!isCalledForCurrentUserLocked()) {

                    return Region.obtain();

                    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 {

                final Region region = Region.obtain();

                getMagnificationController().getMagnificationRegion(region);

                    magnificationController.getMagnificationRegion(region);

                    return region;

                } finally {

                    Binder.restoreCallingIdentity(identity);

                    if (!initiallyRegistered && forceRegistration) {

                        magnificationController.unregister();

                    }

                }

            }

        }
@@ -2940,15 +2965,19 @@ public class AccessibilityManagerService extends IAccessibilityManager.Stub { 
                if (!permissionGranted) {

                    return false;

                }

            }

                final long identity = Binder.clearCallingIdentity();

                try {

                return getMagnificationController().setScaleAndCenter(

                        scale, centerX, centerY, animate, mId);

                    MagnificationController magnificationController = getMagnificationController();

                    if (!magnificationController.isRegisteredLocked()) {

                        magnificationController.register();

                    }

                    return magnificationController

                            .setScaleAndCenter(scale, centerX, centerY, animate, mId);

                } finally {

                    Binder.restoreCallingIdentity(identity);

                }

            }

        }



        @Override

        public void setMagnificationCallbackEnabled(boolean enabled) {

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

+13 −0
Original line number Diff line number Diff line
@@ -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;