Merge "Fix the race condition that cause windows cache stale" (224c55d4) · Commits · e / os / android_frameworks_base

core/java/android/view/accessibility/AccessibilityCache.java

+16 −1

Original line number	Diff line number	Diff line
		@@ -20,6 +20,7 @@ package android.view.accessibility;
		import static android.view.accessibility.AccessibilityNodeInfo.FOCUS_ACCESSIBILITY;

		import android.os.Build;
		import android.os.SystemClock;
		import android.util.ArraySet;
		import android.util.Log;
		import android.util.LongArray;
		@@ -71,6 +72,11 @@ public class AccessibilityCache {

		private long mAccessibilityFocus = AccessibilityNodeInfo.UNDEFINED_ITEM_ID;
		private long mInputFocus = AccessibilityNodeInfo.UNDEFINED_ITEM_ID;
		/**
		* The event time of the {@link AccessibilityEvent} which presents the populated windows cache
		* before it is stale.
		*/
		private long mValidWindowCacheTimeStamp = 0;

		private int mAccessibilityFocusedWindow = AccessibilityWindowInfo.UNDEFINED_WINDOW_ID;
		private int mInputFocusWindow = AccessibilityWindowInfo.UNDEFINED_WINDOW_ID;
		@@ -97,13 +103,20 @@ public class AccessibilityCache {
		* The key of SparseArray is display ID.
		*
		* @param windowsOnAllDisplays The accessibility windows of all displays.
		* @param populationTimeStamp The timestamp from {@link SystemClock#uptimeMillis()} when the
		* client requests the data.
		*/
		public void setWindowsOnAllDisplays(
		SparseArray<List<AccessibilityWindowInfo>> windowsOnAllDisplays) {
		SparseArray<List<AccessibilityWindowInfo>> windowsOnAllDisplays,
		long populationTimeStamp) {
		synchronized (mLock) {
		if (DEBUG) {
		Log.i(LOG_TAG, "Set windows");
		}
		if (mValidWindowCacheTimeStamp > populationTimeStamp) {
		// Discard the windows because it might be stale.
		return;
		}
		clearWindowCacheLocked();
		if (windowsOnAllDisplays == null) {
		return;
		@@ -224,6 +237,7 @@ public class AccessibilityCache {
		} break;

		case AccessibilityEvent.TYPE_WINDOWS_CHANGED:
		mValidWindowCacheTimeStamp = event.getEventTime();
		if (event.getWindowChanges()
		== AccessibilityEvent.WINDOWS_CHANGE_ACCESSIBILITY_FOCUSED) {
		// Don't need to clear all cache. Unless the changes are related to
		@@ -232,6 +246,7 @@ public class AccessibilityCache {
		break;
		}
		case AccessibilityEvent.TYPE_WINDOW_STATE_CHANGED: {
		mValidWindowCacheTimeStamp = event.getEventTime();
		clear();
		} break;
		}

core/java/android/view/accessibility/AccessibilityInteractionClient.java

+3 −1

Original line number	Diff line number	Diff line
		@@ -435,8 +435,10 @@ public final class AccessibilityInteractionClient
		}
		}

		long populationTimeStamp;
		final long identityToken = Binder.clearCallingIdentity();
		try {
		populationTimeStamp = SystemClock.uptimeMillis();
		windows = connection.getWindows();
		} finally {
		Binder.restoreCallingIdentity(identityToken);
		@@ -446,7 +448,7 @@ public final class AccessibilityInteractionClient
		}
		if (windows != null) {
		if (sAccessibilityCache != null) {
		sAccessibilityCache.setWindowsOnAllDisplays(windows);
		sAccessibilityCache.setWindowsOnAllDisplays(windows, populationTimeStamp);
		}
		return windows;
		}

core/tests/coretests/src/android/view/accessibility/AccessibilityCacheTest.java

+49 −2

Original line number	Diff line number	Diff line
		@@ -35,6 +35,7 @@ import static org.mockito.Mockito.never;
		import static org.mockito.Mockito.verify;
		import static org.mockito.Mockito.when;

		import android.os.SystemClock;
		import android.util.SparseArray;
		import android.view.Display;
		import android.view.View;
		@@ -299,7 +300,8 @@ public class AccessibilityCacheTest {
		SparseArray<List<AccessibilityWindowInfo>> allWindows = new SparseArray<>();
		allWindows.put(Display.DEFAULT_DISPLAY, windowsIn1);
		allWindows.put(SECONDARY_DISPLAY_ID, windowsIn2);
		mAccessibilityCache.setWindowsOnAllDisplays(allWindows);
		final long populationTimeStamp = SystemClock.uptimeMillis();
		mAccessibilityCache.setWindowsOnAllDisplays(allWindows, populationTimeStamp);
		// Gets windows at default display.
		windowsOut1 = getWindowsByDisplay(Display.DEFAULT_DISPLAY);
		window1Out = mAccessibilityCache.getWindow(WINDOW_ID_1);
		@@ -338,6 +340,46 @@ public class AccessibilityCacheTest {
		}
		}

		@Test
		public void setInvalidWindowsAfterWindowsChangedEvent_notInCache() {
		final AccessibilityEvent event = new AccessibilityEvent(
		AccessibilityEvent.TYPE_WINDOWS_CHANGED);
		final long eventTime = 1000L;
		event.setEventTime(eventTime);
		mAccessibilityCache.onAccessibilityEvent(event);

		final AccessibilityWindowInfo windowInfo1 = obtainAccessibilityWindowInfo(WINDOW_ID_1,
		SPECIFIC_WINDOW_LAYER);
		List<AccessibilityWindowInfo> windowsIn = Arrays.asList(windowInfo1);
		setWindowsByDisplay(Display.DEFAULT_DISPLAY, windowsIn, eventTime - 10);

		try {
		assertNull(getWindowsByDisplay(Display.DEFAULT_DISPLAY));
		} finally {
		windowInfo1.recycle();
		}
		}

		@Test
		public void setInvalidWindowsAfterStateChangedEvent_notInCache() {
		final AccessibilityEvent event = new AccessibilityEvent(
		AccessibilityEvent.TYPE_WINDOW_STATE_CHANGED);
		final long eventTime = 1000L;
		event.setEventTime(eventTime);
		mAccessibilityCache.onAccessibilityEvent(event);

		final AccessibilityWindowInfo windowInfo1 = obtainAccessibilityWindowInfo(WINDOW_ID_1,
		SPECIFIC_WINDOW_LAYER);
		List<AccessibilityWindowInfo> windowsIn = Arrays.asList(windowInfo1);
		setWindowsByDisplay(Display.DEFAULT_DISPLAY, windowsIn, eventTime - 10);

		try {
		assertNull(getWindowsByDisplay(Display.DEFAULT_DISPLAY));
		} finally {
		windowInfo1.recycle();
		}
		}

		@Test
		public void addWindowThenStateChangedEvent_noLongerInCache() {
		putWindowWithWindowIdAndDisplayIdInCache(WINDOW_ID_1, Display.DEFAULT_DISPLAY,
		@@ -1063,9 +1105,14 @@ public class AccessibilityCacheTest {
		}

		private void setWindowsByDisplay(int displayId, List<AccessibilityWindowInfo> windows) {
		setWindowsByDisplay(displayId, windows, SystemClock.uptimeMillis());
		}

		private void setWindowsByDisplay(int displayId, List<AccessibilityWindowInfo> windows,
		long populationTimeStamp) {
		SparseArray<List<AccessibilityWindowInfo>> allWindows = new SparseArray<>();
		allWindows.put(displayId, windows);
		mAccessibilityCache.setWindowsOnAllDisplays(allWindows);
		mAccessibilityCache.setWindowsOnAllDisplays(allWindows, populationTimeStamp);
		}

		private List<AccessibilityWindowInfo> getWindowsByDisplay(int displayId) {