Ensure register/unregister OnBackInvokedCallback thread safed. (713eaa58) · Commits · e / os / android_frameworks_base

core/java/android/window/WindowOnBackInvokedDispatcher.java

+124 −97

Original line number	Diff line number	Diff line
		@@ -36,6 +36,8 @@ import android.view.ImeBackAnimationController;
		import androidx.annotation.VisibleForTesting;


		import com.android.internal.annotations.GuardedBy;

		import java.io.PrintWriter;
		import java.lang.ref.WeakReference;
		import java.util.ArrayList;
		@@ -75,14 +77,17 @@ public class WindowOnBackInvokedDispatcher implements OnBackInvokedDispatcher {
		@Nullable
		private ImeBackAnimationController mImeBackAnimationController;

		@GuardedBy("mLock")
		/** Convenience hashmap to quickly decide if a callback has been added. */
		private final HashMap<OnBackInvokedCallback, Integer> mAllCallbacks = new HashMap<>();
		/** Holds all callbacks by priorities. */

		@VisibleForTesting
		@GuardedBy("mLock")
		public final TreeMap<Integer, ArrayList<OnBackInvokedCallback>>
		mOnBackInvokedCallbacks = new TreeMap<>();
		private Checker mChecker;
		private final Object mLock = new Object();

		public WindowOnBackInvokedDispatcher(@NonNull Context context) {
		mChecker = new Checker(context);
		@@ -94,6 +99,7 @@ public class WindowOnBackInvokedDispatcher implements OnBackInvokedDispatcher {
		*/
		public void attachToWindow(@NonNull IWindowSession windowSession, @NonNull IWindow window,
		@Nullable ImeBackAnimationController imeBackAnimationController) {
		synchronized (mLock) {
		mWindowSession = windowSession;
		mWindow = window;
		mImeBackAnimationController = imeBackAnimationController;
		@@ -101,14 +107,17 @@ public class WindowOnBackInvokedDispatcher implements OnBackInvokedDispatcher {
		setTopOnBackInvokedCallback(getTopCallback());
		}
		}
		}

		/** Detaches the dispatcher instance from its window. */
		public void detachFromWindow() {
		synchronized (mLock) {
		clear();
		mWindow = null;
		mWindowSession = null;
		mImeBackAnimationController = null;
		}
		}

		// TODO: Take an Executor for the callback to run on.
		@Override
		@@ -125,6 +134,7 @@ public class WindowOnBackInvokedDispatcher implements OnBackInvokedDispatcher {
		*/
		public void registerOnBackInvokedCallbackUnchecked(
		@NonNull OnBackInvokedCallback callback, @Priority int priority) {
		synchronized (mLock) {
		if (mImeDispatcher != null) {
		mImeDispatcher.registerOnBackInvokedCallback(priority, callback);
		return;
		@@ -155,9 +165,11 @@ public class WindowOnBackInvokedDispatcher implements OnBackInvokedDispatcher {
		setTopOnBackInvokedCallback(callback);
		}
		}
		}

		@Override
		public void unregisterOnBackInvokedCallback(@NonNull OnBackInvokedCallback callback) {
		synchronized (mLock) {
		if (mImeDispatcher != null) {
		mImeDispatcher.unregisterOnBackInvokedCallback(callback);
		return;
		@@ -179,28 +191,37 @@ public class WindowOnBackInvokedDispatcher implements OnBackInvokedDispatcher {
		mOnBackInvokedCallbacks.remove(priority);
		}
		mAllCallbacks.remove(callback);
		// Re-populate the top callback to WM if the removed callback was previously the top one.
		// Re-populate the top callback to WM if the removed callback was previously the top
		// one.
		if (previousTopCallback == callback) {
		// We should call onBackCancelled() when an active callback is removed from dispatcher.
		// We should call onBackCancelled() when an active callback is removed from
		// dispatcher.
		sendCancelledIfInProgress(callback);
		setTopOnBackInvokedCallback(getTopCallback());
		}
		}
		}

		/**
		* Indicates if the dispatcher is actively dispatching to a callback.
		*/
		public boolean isDispatching() {
		synchronized (mLock) {
		return mIsDispatching;
		}
		}

		private void onStartDispatching() {
		synchronized (mLock) {
		mIsDispatching = true;
		}
		}

		private void onStopDispatching() {
		synchronized (mLock) {
		mIsDispatching = false;
		}
		}

		private void sendCancelledIfInProgress(@NonNull OnBackInvokedCallback callback) {
		boolean isInProgress = mProgressAnimator.isBackAnimationInProgress();
		@@ -223,6 +244,7 @@ public class WindowOnBackInvokedDispatcher implements OnBackInvokedDispatcher {

		/** Clears all registered callbacks on the instance. */
		public void clear() {
		synchronized (mLock) {
		if (mImeDispatcher != null) {
		mImeDispatcher.clear();
		mImeDispatcher = null;
		@@ -245,6 +267,7 @@ public class WindowOnBackInvokedDispatcher implements OnBackInvokedDispatcher {
		mAllCallbacks.clear();
		mOnBackInvokedCallbacks.clear();
		}
		}

		private void setTopOnBackInvokedCallback(@Nullable OnBackInvokedCallback callback) {
		if (mWindowSession == null \|\| mWindow == null) {
		@@ -275,6 +298,7 @@ public class WindowOnBackInvokedDispatcher implements OnBackInvokedDispatcher {
		}

		public OnBackInvokedCallback getTopCallback() {
		synchronized (mLock) {
		if (mAllCallbacks.isEmpty()) {
		return null;
		}
		@@ -284,6 +308,7 @@ public class WindowOnBackInvokedDispatcher implements OnBackInvokedDispatcher {
		return callbacks.get(callbacks.size() - 1);
		}
		}
		}
		return null;
		}

		@@ -315,6 +340,7 @@ public class WindowOnBackInvokedDispatcher implements OnBackInvokedDispatcher {
		public void dump(String prefix, PrintWriter writer) {
		String innerPrefix = prefix + " ";
		writer.println(prefix + "WindowOnBackDispatcher:");
		synchronized (mLock) {
		if (mAllCallbacks.isEmpty()) {
		writer.println(prefix + "<None>");
		return;
		@@ -326,6 +352,7 @@ public class WindowOnBackInvokedDispatcher implements OnBackInvokedDispatcher {
		writer.println(innerPrefix + " Callback: " + callback + " Priority=" + priority);
		});
		}
		}

		static class OnBackInvokedCallbackWrapper extends IOnBackInvokedCallback.Stub {
		static class CallbackRef {