services/core/java/com/android/server/wm/AppWindowToken.java

/*
 * Copyright (C) 2011 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.android.server.wm;

import static android.content.pm.ActivityInfo.CONFIG_ORIENTATION;
import static android.content.pm.ActivityInfo.CONFIG_SCREEN_SIZE;
import static android.content.pm.ActivityInfo.SCREEN_ORIENTATION_BEHIND;
import static android.content.pm.ActivityInfo.SCREEN_ORIENTATION_UNSET;
import static android.os.Trace.TRACE_TAG_WINDOW_MANAGER;
import static android.view.Display.DEFAULT_DISPLAY;
import static android.view.WindowManager.LayoutParams.FLAG_DISMISS_KEYGUARD;
import static android.view.WindowManager.LayoutParams.FLAG_SECURE;
import static android.view.WindowManager.LayoutParams.FLAG_SHOW_WHEN_LOCKED;
import static android.view.WindowManager.LayoutParams.TYPE_APPLICATION;
import static android.view.WindowManager.LayoutParams.TYPE_APPLICATION_STARTING;
import static android.view.WindowManager.LayoutParams.TYPE_BASE_APPLICATION;
import static com.android.server.policy.WindowManagerPolicy.FINISH_LAYOUT_REDO_ANIM;
import static com.android.server.policy.WindowManagerPolicy.FINISH_LAYOUT_REDO_WALLPAPER;
import static com.android.server.wm.AppTransition.TRANSIT_UNSET;
import static com.android.server.wm.WindowManagerDebugConfig.DEBUG_ADD_REMOVE;
import static com.android.server.wm.WindowManagerDebugConfig.DEBUG_ANIM;
import static com.android.server.wm.WindowManagerDebugConfig.DEBUG_APP_TRANSITIONS;
import static com.android.server.wm.WindowManagerDebugConfig.DEBUG_FOCUS_LIGHT;
import static com.android.server.wm.WindowManagerDebugConfig.DEBUG_LAYOUT_REPEATS;
import static com.android.server.wm.WindowManagerDebugConfig.DEBUG_ORIENTATION;
import static com.android.server.wm.WindowManagerDebugConfig.DEBUG_STARTING_WINDOW;
import static com.android.server.wm.WindowManagerDebugConfig.DEBUG_STARTING_WINDOW_VERBOSE;
import static com.android.server.wm.WindowManagerDebugConfig.DEBUG_TOKEN_MOVEMENT;
import static com.android.server.wm.WindowManagerDebugConfig.DEBUG_VISIBILITY;
import static com.android.server.wm.WindowManagerDebugConfig.DEBUG_WINDOW_MOVEMENT;
import static com.android.server.wm.WindowManagerDebugConfig.TAG_WITH_CLASS_NAME;
import static com.android.server.wm.WindowManagerDebugConfig.TAG_WM;
import static com.android.server.wm.WindowManagerService.H.NOTIFY_ACTIVITY_DRAWN;
import static com.android.server.wm.WindowManagerService.UPDATE_FOCUS_NORMAL;
import static com.android.server.wm.WindowManagerService.UPDATE_FOCUS_WILL_PLACE_SURFACES;
import static com.android.server.wm.WindowManagerService.logWithStack;
import static com.android.server.wm.proto.AppWindowTokenProto.NAME;
import static com.android.server.wm.proto.AppWindowTokenProto.WINDOW_TOKEN;

import android.annotation.CallSuper;
import android.app.Activity;
import android.content.res.Configuration;
import android.graphics.GraphicBuffer;
import android.graphics.Point;
import android.graphics.Rect;
import android.os.Binder;
import android.os.Debug;
import android.os.IBinder;
import android.os.RemoteException;
import android.os.Trace;
import android.util.Slog;
import android.util.proto.ProtoOutputStream;
import android.view.DisplayInfo;
import android.view.SurfaceControl.Transaction;
import android.view.animation.Animation;
import android.view.IApplicationToken;
import android.view.SurfaceControl;
import android.view.WindowManager;
import android.view.WindowManager.LayoutParams;

import com.android.internal.util.ToBooleanFunction;
import com.android.server.input.InputApplicationHandle;
import com.android.server.policy.WindowManagerPolicy.StartingSurface;
import com.android.server.wm.WindowManagerService.H;

import java.io.PrintWriter;
import java.util.ArrayDeque;
import java.util.ArrayList;
import java.util.LinkedList;

class AppTokenList extends ArrayList<AppWindowToken> {
}

/**
 * Version of WindowToken that is specifically for a particular application (or
 * really activity) that is displaying windows.
 */
class AppWindowToken extends WindowToken implements WindowManagerService.AppFreezeListener {
    private static final String TAG = TAG_WITH_CLASS_NAME ? "AppWindowToken" : TAG_WM;

    /**
     * Value to increment the z-layer when boosting a layer during animations. BOOST in l33tsp34k.
     */
    private static final int Z_BOOST_BASE = 800570000;

    // Non-null only for application tokens.
    final IApplicationToken appToken;

    final boolean mVoiceInteraction;

    /** @see WindowContainer#fillsParent() */
    private boolean mFillsParent;
    boolean layoutConfigChanges;
    boolean mShowForAllUsers;
    int mTargetSdk;

    // Flag set while reparenting to prevent actions normally triggered by an individual parent
    // change.
    private boolean mReparenting;

    // True if we are current in the process of removing this app token from the display
    private boolean mRemovingFromDisplay = false;

    // The input dispatching timeout for this application token in nanoseconds.
    long mInputDispatchingTimeoutNanos;

    // These are used for determining when all windows associated with
    // an activity have been drawn, so they can be made visible together
    // at the same time.
    // initialize so that it doesn't match mTransactionSequence which is an int.
    private long mLastTransactionSequence = Long.MIN_VALUE;
    private int mNumInterestingWindows;
    private int mNumDrawnWindows;
    boolean inPendingTransaction;
    boolean allDrawn;
    private boolean mLastAllDrawn;

    // Set to true when this app creates a surface while in the middle of an animation. In that
    // case do not clear allDrawn until the animation completes.
    boolean deferClearAllDrawn;

    // Is this window's surface needed?  This is almost like hidden, except
    // it will sometimes be true a little earlier: when the token has
    // been shown, but is still waiting for its app transition to execute
    // before making its windows shown.
    boolean hiddenRequested;

    // Have we told the window clients to hide themselves?
    private boolean mClientHidden;

    // If true we will defer setting mClientHidden to true and reporting to the client that it is
    // hidden.
    boolean mDeferHidingClient;

    // Last visibility state we reported to the app token.
    boolean reportedVisible;

    // Last drawn state we reported to the app token.
    private boolean reportedDrawn;

    // Set to true when the token has been removed from the window mgr.
    boolean removed;

    // Information about an application starting window if displayed.
    StartingData startingData;
    WindowState startingWindow;
    StartingSurface startingSurface;
    boolean startingDisplayed;
    boolean startingMoved;
    // True if the hidden state of this token was forced to false due to a transferred starting
    // window.
    private boolean mHiddenSetFromTransferredStartingWindow;
    boolean firstWindowDrawn;
    private final WindowState.UpdateReportedVisibilityResults mReportedVisibilityResults =
            new WindowState.UpdateReportedVisibilityResults();

    // Input application handle used by the input dispatcher.
    final InputApplicationHandle mInputApplicationHandle;

    // TODO: Have a WindowContainer state for tracking exiting/deferred removal.
    boolean mIsExiting;

    boolean mLaunchTaskBehind;
    boolean mEnteringAnimation;

    private boolean mAlwaysFocusable;

    boolean mAppStopped;
    int mRotationAnimationHint;
    private int mPendingRelaunchCount;

    private boolean mLastContainsShowWhenLockedWindow;
    private boolean mLastContainsDismissKeyguardWindow;

    ArrayDeque<Rect> mFrozenBounds = new ArrayDeque<>();
    ArrayDeque<Configuration> mFrozenMergedConfig = new ArrayDeque<>();

    private boolean mDisablePreviewScreenshots;

    private Task mLastParent;

    /**
     * See {@link #canTurnScreenOn()}
     */
    private boolean mCanTurnScreenOn = true;

    /**
     * If we are running an animation, this determines the transition type. Must be one of
     * AppTransition.TRANSIT_* constants.
     */
    private int mTransit;

    /**
     * If we are running an animation, this determines the flags during this animation. Must be a
     * bitwise combination of AppTransition.TRANSIT_FLAG_* constants.
     */
    private int mTransitFlags;

    /** Whether our surface was set to be showing in the last call to {@link #prepareSurfaces} */
    private boolean mLastSurfaceShowing;

    private AppWindowThumbnail mThumbnail;

    /** Have we been asked to have this token keep the screen frozen? */
    private boolean mFreezingScreen;

    /** Whether this token should be boosted at the top of all app window tokens. */
    private boolean mNeedsZBoost;

    private final Point mTmpPoint = new Point();

    AppWindowToken(WindowManagerService service, IApplicationToken token, boolean voiceInteraction,
            DisplayContent dc, long inputDispatchingTimeoutNanos, boolean fullscreen,
            boolean showForAllUsers, int targetSdk, int orientation, int rotationAnimationHint,
            int configChanges, boolean launchTaskBehind, boolean alwaysFocusable,
            AppWindowContainerController controller) {
        this(service, token, voiceInteraction, dc, fullscreen);
        setController(controller);
        mInputDispatchingTimeoutNanos = inputDispatchingTimeoutNanos;
        mShowForAllUsers = showForAllUsers;
        mTargetSdk = targetSdk;
        mOrientation = orientation;
        layoutConfigChanges = (configChanges & (CONFIG_SCREEN_SIZE | CONFIG_ORIENTATION)) != 0;
        mLaunchTaskBehind = launchTaskBehind;
        mAlwaysFocusable = alwaysFocusable;
        mRotationAnimationHint = rotationAnimationHint;

        // Application tokens start out hidden.
        setHidden(true);
        hiddenRequested = true;
    }

    AppWindowToken(WindowManagerService service, IApplicationToken token, boolean voiceInteraction,
            DisplayContent dc, boolean fillsParent) {
        super(service, token != null ? token.asBinder() : null, TYPE_APPLICATION, true, dc,
                false /* ownerCanManageAppTokens */);
        appToken = token;
        mVoiceInteraction = voiceInteraction;
        mFillsParent = fillsParent;
        mInputApplicationHandle = new InputApplicationHandle(this);
    }

    void onFirstWindowDrawn(WindowState win, WindowStateAnimator winAnimator) {
        firstWindowDrawn = true;

        // We now have a good window to show, remove dead placeholders
        removeDeadWindows();

        if (startingWindow != null) {
            if (DEBUG_STARTING_WINDOW || DEBUG_ANIM) Slog.v(TAG, "Finish starting "
                    + win.mToken + ": first real window is shown, no animation");
            // If this initial window is animating, stop it -- we will do an animation to reveal
            // it from behind the starting window, so there is no need for it to also be doing its
            // own stuff.
            win.cancelAnimation();
            if (getController() != null) {
                getController().removeStartingWindow();
            }
        }
        updateReportedVisibilityLocked();
    }

    void updateReportedVisibilityLocked() {
        if (appToken == null) {
            return;
        }

        if (DEBUG_VISIBILITY) Slog.v(TAG, "Update reported visibility: " + this);
        final int count = mChildren.size();

        mReportedVisibilityResults.reset();

        for (int i = 0; i < count; i++) {
            final WindowState win = mChildren.get(i);
            win.updateReportedVisibility(mReportedVisibilityResults);
        }

        int numInteresting = mReportedVisibilityResults.numInteresting;
        int numVisible = mReportedVisibilityResults.numVisible;
        int numDrawn = mReportedVisibilityResults.numDrawn;
        boolean nowGone = mReportedVisibilityResults.nowGone;

        boolean nowDrawn = numInteresting > 0 && numDrawn >= numInteresting;
        boolean nowVisible = numInteresting > 0 && numVisible >= numInteresting && !isHidden();
        if (!nowGone) {
            // If the app is not yet gone, then it can only become visible/drawn.
            if (!nowDrawn) {
                nowDrawn = reportedDrawn;
            }
            if (!nowVisible) {
                nowVisible = reportedVisible;
            }
        }
        if (DEBUG_VISIBILITY) Slog.v(TAG, "VIS " + this + ": interesting="
                + numInteresting + " visible=" + numVisible);
        final AppWindowContainerController controller = getController();
        if (nowDrawn != reportedDrawn) {
            if (nowDrawn) {
                if (controller != null) {
                    controller.reportWindowsDrawn();
                }
            }
            reportedDrawn = nowDrawn;
        }
        if (nowVisible != reportedVisible) {
            if (DEBUG_VISIBILITY) Slog.v(TAG,
                    "Visibility changed in " + this + ": vis=" + nowVisible);
            reportedVisible = nowVisible;
            if (controller != null) {
                if (nowVisible) {
                    controller.reportWindowsVisible();
                } else {
                    controller.reportWindowsGone();
                }
            }
        }
    }

    boolean isClientHidden() {
        return mClientHidden;
    }

    void setClientHidden(boolean hideClient) {
        if (mClientHidden == hideClient || (hideClient && mDeferHidingClient)) {
            return;
        }
        mClientHidden = hideClient;
        sendAppVisibilityToClients();
    }

    boolean setVisibility(WindowManager.LayoutParams lp,
            boolean visible, int transit, boolean performLayout, boolean isVoiceInteraction) {

        boolean delayed = false;
        inPendingTransaction = false;
        // Reset the state of mHiddenSetFromTransferredStartingWindow since visibility is actually
        // been set by the app now.
        mHiddenSetFromTransferredStartingWindow = false;
        setClientHidden(!visible);

        // Allow for state changes and animation to be applied if:
        // * token is transitioning visibility state
        // * or the token was marked as hidden and is exiting before we had a chance to play the
        // transition animation
        // * or this is an opening app and windows are being replaced.
        boolean visibilityChanged = false;
        if (isHidden() == visible || (isHidden() && mIsExiting) || (visible && waitingForReplacement())) {
            final AccessibilityController accessibilityController = mService.mAccessibilityController;
            boolean changed = false;
            if (DEBUG_APP_TRANSITIONS) Slog.v(TAG_WM,
                    "Changing app " + this + " hidden=" + isHidden() + " performLayout=" + performLayout);

            boolean runningAppAnimation = false;

            if (transit != AppTransition.TRANSIT_UNSET) {
                if (applyAnimationLocked(lp, transit, visible, isVoiceInteraction)) {
                    delayed = runningAppAnimation = true;
                }
                final WindowState window = findMainWindow();
                //TODO (multidisplay): Magnification is supported only for the default display.
                if (window != null && accessibilityController != null
                        && getDisplayContent().getDisplayId() == DEFAULT_DISPLAY) {
                    accessibilityController.onAppWindowTransitionLocked(window, transit);
                }
                changed = true;
            }

            final int windowsCount = mChildren.size();
            for (int i = 0; i < windowsCount; i++) {
                final WindowState win = mChildren.get(i);
                changed |= win.onAppVisibilityChanged(visible, runningAppAnimation);
            }

            setHidden(!visible);
            hiddenRequested = !visible;
            visibilityChanged = true;
            if (!visible) {
                stopFreezingScreen(true, true);
            } else {
                // If we are being set visible, and the starting window is not yet displayed,
                // then make sure it doesn't get displayed.
                if (startingWindow != null && !startingWindow.isDrawnLw()) {
                    startingWindow.mPolicyVisibility = false;
                    startingWindow.mPolicyVisibilityAfterAnim = false;
                }

                // We are becoming visible, so better freeze the screen with the windows that are
                // getting visible so we also wait for them.
                forAllWindows(mService::makeWindowFreezingScreenIfNeededLocked, true);
            }

            if (DEBUG_APP_TRANSITIONS) Slog.v(TAG_WM, "setVisibility: " + this
                    + ": hidden=" + isHidden() + " hiddenRequested=" + hiddenRequested);

            if (changed) {
                mService.mInputMonitor.setUpdateInputWindowsNeededLw();
                if (performLayout) {
                    mService.updateFocusedWindowLocked(UPDATE_FOCUS_WILL_PLACE_SURFACES,
                            false /*updateInputWindows*/);
                    mService.mWindowPlacerLocked.performSurfacePlacement();
                }
                mService.mInputMonitor.updateInputWindowsLw(false /*force*/);
            }
        }

        if (isReallyAnimating()) {
            delayed = true;
        }

        for (int i = mChildren.size() - 1; i >= 0 && !delayed; i--) {
            if ((mChildren.get(i)).isSelfOrChildAnimating()) {
                delayed = true;
            }
        }

        if (visibilityChanged) {
            if (visible && !delayed) {
                // The token was made immediately visible, there will be no entrance animation.
                // We need to inform the client the enter animation was finished.
                mEnteringAnimation = true;
                mService.mActivityManagerAppTransitionNotifier.onAppTransitionFinishedLocked(token);
            }

            // If we are hidden but there is no delay needed we immediately
            // apply the Surface transaction so that the ActivityManager
            // can have some guarantee on the Surface state following
            // setting the visibility. This captures cases like dismissing
            // the docked or pinned stack where there is no app transition.
            //
            // In the case of a "Null" animation, there will be
            // no animation but there will still be a transition set.
            // We still need to delay hiding the surface such that it
            // can be synchronized with showing the next surface in the transition.
            if (isHidden() && !delayed && !mService.mAppTransition.isTransitionSet()) {
                SurfaceControl.openTransaction();
                for (int i = mChildren.size() - 1; i >= 0; i--) {
                    mChildren.get(i).mWinAnimator.hide("immediately hidden");
                }
                SurfaceControl.closeTransaction();
            }

            if (!mService.mClosingApps.contains(this) && !mService.mOpeningApps.contains(this)) {
                // The token is not closing nor opening, so even if there is an animation set, that
                // doesn't mean that it goes through the normal app transition cycle so we have
                // to inform the docked controller about visibility change.
                // TODO(multi-display): notify docked divider on all displays where visibility was
                // affected.
                mService.getDefaultDisplayContentLocked().getDockedDividerController()
                        .notifyAppVisibilityChanged();
                mService.mTaskSnapshotController.notifyAppVisibilityChanged(this, visible);
            }
        }

        return delayed;
    }

    /**
     * @return The to top most child window for which {@link LayoutParams#isFullscreen()} returns
     *         true.
     */
    WindowState getTopFullscreenWindow() {
        for (int i = mChildren.size() - 1; i >= 0; i--) {
            final WindowState win = mChildren.get(i);
            if (win != null && win.mAttrs.isFullscreen()) {
                return win;
            }
        }
        return null;
    }

    WindowState findMainWindow() {
        WindowState candidate = null;
        int j = mChildren.size();
        while (j > 0) {
            j--;
            final WindowState win = mChildren.get(j);
            final int type = win.mAttrs.type;
            // No need to loop through child window as base application and starting types can't be
            // child windows.
            if (type == TYPE_BASE_APPLICATION || type == TYPE_APPLICATION_STARTING) {
                // In cases where there are multiple windows, we prefer the non-exiting window. This
                // happens for example when replacing windows during an activity relaunch. When
                // constructing the animation, we want the new window, not the exiting one.
                if (win.mAnimatingExit) {
                    candidate = win;
                } else {
                    return win;
                }
            }
        }
        return candidate;
    }

    boolean windowsAreFocusable() {
        return getWindowConfiguration().canReceiveKeys() || mAlwaysFocusable;
    }

    AppWindowContainerController getController() {
        final WindowContainerController controller = super.getController();
        return controller != null ? (AppWindowContainerController) controller : null;
    }

    @Override
    boolean isVisible() {
        // If the app token isn't hidden then it is considered visible and there is no need to check
        // its children windows to see if they are visible.
        return !isHidden();
    }

    @Override
    void removeImmediately() {
        onRemovedFromDisplay();
        super.removeImmediately();
    }

    @Override
    void removeIfPossible() {
        mIsExiting = false;
        removeAllWindowsIfPossible();
        removeImmediately();
    }

    @Override
    boolean checkCompleteDeferredRemoval() {
        if (mIsExiting) {
            removeIfPossible();
        }
        return super.checkCompleteDeferredRemoval();
    }

    void onRemovedFromDisplay() {
        if (mRemovingFromDisplay) {
            return;
        }
        mRemovingFromDisplay = true;

        if (DEBUG_APP_TRANSITIONS) Slog.v(TAG_WM, "Removing app token: " + this);

        boolean delayed = setVisibility(null, false, TRANSIT_UNSET, true, mVoiceInteraction);

        mService.mOpeningApps.remove(this);
        mService.mUnknownAppVisibilityController.appRemovedOrHidden(this);
        mService.mTaskSnapshotController.onAppRemoved(this);
        waitingToShow = false;
        if (mService.mClosingApps.contains(this)) {
            delayed = true;
        } else if (mService.mAppTransition.isTransitionSet()) {
            mService.mClosingApps.add(this);
            delayed = true;
        }

        if (DEBUG_APP_TRANSITIONS) Slog.v(TAG_WM, "Removing app " + this + " delayed=" + delayed
                + " animation=" + getAnimation() + " animating=" + isSelfAnimating());

        if (DEBUG_ADD_REMOVE || DEBUG_TOKEN_MOVEMENT) Slog.v(TAG_WM, "removeAppToken: "
                + this + " delayed=" + delayed + " Callers=" + Debug.getCallers(4));

        if (startingData != null && getController() != null) {
            getController().removeStartingWindow();
        }

        // If this window was animating, then we need to ensure that the app transition notifies
        // that animations have completed in WMS.handleAnimatingStoppedAndTransitionLocked(), so
        // add to that list now
        if (isSelfAnimating()) {
            mService.mNoAnimationNotifyOnTransitionFinished.add(token);
        }

        final TaskStack stack = getStack();
        if (delayed && !isEmpty()) {
            // set the token aside because it has an active animation to be finished
            if (DEBUG_ADD_REMOVE || DEBUG_TOKEN_MOVEMENT) Slog.v(TAG_WM,
                    "removeAppToken make exiting: " + this);
            if (stack != null) {
                stack.mExitingAppTokens.add(this);
            }
            mIsExiting = true;
        } else {
            // Make sure there is no animation running on this token, so any windows associated
            // with it will be removed as soon as their animations are complete
            cancelAnimation();
            if (stack != null) {
                stack.mExitingAppTokens.remove(this);
            }
            removeIfPossible();
        }

        removed = true;
        stopFreezingScreen(true, true);

        if (mService.mFocusedApp == this) {
            if (DEBUG_FOCUS_LIGHT) Slog.v(TAG_WM, "Removing focused app token:" + this);
            mService.mFocusedApp = null;
            mService.updateFocusedWindowLocked(UPDATE_FOCUS_NORMAL, true /*updateInputWindows*/);
            mService.mInputMonitor.setFocusedAppLw(null);
        }

        if (!delayed) {
            updateReportedVisibilityLocked();
        }

        mRemovingFromDisplay = false;
    }

    void clearAnimatingFlags() {
        boolean wallpaperMightChange = false;
        for (int i = mChildren.size() - 1; i >= 0; i--) {
            final WindowState win = mChildren.get(i);
            wallpaperMightChange |= win.clearAnimatingFlags();
        }
        if (wallpaperMightChange) {
            requestUpdateWallpaperIfNeeded();
        }
    }

    void destroySurfaces() {
        destroySurfaces(false /*cleanupOnResume*/);
    }

    /**
     * Destroy surfaces which have been marked as eligible by the animator, taking care to ensure
     * the client has finished with them.
     *
     * @param cleanupOnResume whether this is done when app is resumed without fully stopped. If
     * set to true, destroy only surfaces of removed windows, and clear relevant flags of the
     * others so that they are ready to be reused. If set to false (common case), destroy all
     * surfaces that's eligible, if the app is already stopped.
     */
    private void destroySurfaces(boolean cleanupOnResume) {
        boolean destroyedSomething = false;

        // Copying to a different list as multiple children can be removed.
        // TODO: Not sure why this is needed.
        final LinkedList<WindowState> children = new LinkedList<>(mChildren);
        for (int i = children.size() - 1; i >= 0; i--) {
            final WindowState win = children.get(i);
            destroyedSomething |= win.destroySurface(cleanupOnResume, mAppStopped);
        }
        if (destroyedSomething) {
            final DisplayContent dc = getDisplayContent();
            dc.assignWindowLayers(true /*setLayoutNeeded*/);
        }
    }

    /**
     * Notify that the app is now resumed, and it was not stopped before, perform a clean
     * up of the surfaces
     */
    void notifyAppResumed(boolean wasStopped) {
        if (DEBUG_ADD_REMOVE) Slog.v(TAG, "notifyAppResumed: wasStopped=" + wasStopped
                + " " + this);
        mAppStopped = false;
        // Allow the window to turn the screen on once the app is resumed again.
        setCanTurnScreenOn(true);
        if (!wasStopped) {
            destroySurfaces(true /*cleanupOnResume*/);
        }
    }

    /**
     * Notify that the app has stopped, and it is okay to destroy any surfaces which were
     * keeping alive in case they were still being used.
     */
    void notifyAppStopped() {
        if (DEBUG_ADD_REMOVE) Slog.v(TAG, "notifyAppStopped: " + this);
        mAppStopped = true;
        destroySurfaces();
        // Remove any starting window that was added for this app if they are still around.
        if (getController() != null) {
            getController().removeStartingWindow();
        }
    }

    void clearAllDrawn() {
        allDrawn = false;
        deferClearAllDrawn = false;
    }

    Task getTask() {
        return (Task) getParent();
    }

    TaskStack getStack() {
        final Task task = getTask();
        if (task != null) {
            return task.mStack;
        } else {
            return null;
        }
    }

    @Override
    void onParentSet() {
        super.onParentSet();

        final Task task = getTask();

        // When the associated task is {@code null}, the {@link AppWindowToken} can no longer
        // access visual elements like the {@link DisplayContent}. We must remove any associations
        // such as animations.
        if (!mReparenting) {
            if (task == null) {
                // It is possible we have been marked as a closing app earlier. We must remove ourselves
                // from this list so we do not participate in any future animations.
                mService.mClosingApps.remove(this);
            } else if (mLastParent != null && mLastParent.mStack != null) {
                task.mStack.mExitingAppTokens.remove(this);
            }
        }
        mLastParent = task;
    }

    void postWindowRemoveStartingWindowCleanup(WindowState win) {
        // TODO: Something smells about the code below...Is there a better way?
        if (startingWindow == win) {
            if (DEBUG_STARTING_WINDOW) Slog.v(TAG_WM, "Notify removed startingWindow " + win);
            if (getController() != null) {
                getController().removeStartingWindow();
            }
        } else if (mChildren.size() == 0) {
            // If this is the last window and we had requested a starting transition window,
            // well there is no point now.
            if (DEBUG_STARTING_WINDOW) Slog.v(TAG_WM, "Nulling last startingData");
            startingData = null;
            if (mHiddenSetFromTransferredStartingWindow) {
                // We set the hidden state to false for the token from a transferred starting window.
                // We now reset it back to true since the starting window was the last window in the
                // token.
                setHidden(true);
            }
        } else if (mChildren.size() == 1 && startingSurface != null && !isRelaunching()) {
            // If this is the last window except for a starting transition window,
            // we need to get rid of the starting transition.
            if (DEBUG_STARTING_WINDOW) Slog.v(TAG_WM, "Last window, removing starting window "
                    + win);
            if (getController() != null) {
                getController().removeStartingWindow();
            }
        }
    }

    void removeDeadWindows() {
        for (int winNdx = mChildren.size() - 1; winNdx >= 0; --winNdx) {
            WindowState win = mChildren.get(winNdx);
            if (win.mAppDied) {
                if (DEBUG_WINDOW_MOVEMENT || DEBUG_ADD_REMOVE) Slog.w(TAG,
                        "removeDeadWindows: " + win);
                // Set mDestroying, we don't want any animation or delayed removal here.
                win.mDestroying = true;
                // Also removes child windows.
                win.removeIfPossible();
            }
        }
    }

    boolean hasWindowsAlive() {
        for (int i = mChildren.size() - 1; i >= 0; i--) {
            // No need to loop through child windows as the answer should be the same as that of the
            // parent window.
            if (!(mChildren.get(i)).mAppDied) {
                return true;
            }
        }
        return false;
    }

    void setWillReplaceWindows(boolean animate) {
        if (DEBUG_ADD_REMOVE) Slog.d(TAG_WM,
                "Marking app token " + this + " with replacing windows.");

        for (int i = mChildren.size() - 1; i >= 0; i--) {
            final WindowState w = mChildren.get(i);
            w.setWillReplaceWindow(animate);
        }
    }

    void setWillReplaceChildWindows() {
        if (DEBUG_ADD_REMOVE) Slog.d(TAG_WM, "Marking app token " + this
                + " with replacing child windows.");
        for (int i = mChildren.size() - 1; i >= 0; i--) {
            final WindowState w = mChildren.get(i);
            w.setWillReplaceChildWindows();
        }
    }

    void clearWillReplaceWindows() {
        if (DEBUG_ADD_REMOVE) Slog.d(TAG_WM,
                "Resetting app token " + this + " of replacing window marks.");

        for (int i = mChildren.size() - 1; i >= 0; i--) {
            final WindowState w = mChildren.get(i);
            w.clearWillReplaceWindow();
        }
    }

    void requestUpdateWallpaperIfNeeded() {
        for (int i = mChildren.size() - 1; i >= 0; i--) {
            final WindowState w = mChildren.get(i);
            w.requestUpdateWallpaperIfNeeded();
        }
    }

    boolean isRelaunching() {
        return mPendingRelaunchCount > 0;
    }

    boolean shouldFreezeBounds() {
        final Task task = getTask();

        // For freeform windows, we can't freeze the bounds at the moment because this would make
        // the resizing unresponsive.
        if (task == null || task.inFreeformWindowingMode()) {
            return false;
        }

        // We freeze the bounds while drag resizing to deal with the time between
        // the divider/drag handle being released, and the handling it's new
        // configuration. If we are relaunched outside of the drag resizing state,
        // we need to be careful not to do this.
        return getTask().isDragResizing();
    }

    void startRelaunching() {
        if (shouldFreezeBounds()) {
            freezeBounds();
        }

        // In the process of tearing down before relaunching, the app will
        // try and clean up it's child surfaces. We need to prevent this from
        // happening, so we sever the children, transfering their ownership
        // from the client it-self to the parent surface (owned by us).
        for (int i = mChildren.size() - 1; i >= 0; i--) {
            final WindowState w = mChildren.get(i);
            w.mWinAnimator.detachChildren();
        }

        mPendingRelaunchCount++;
    }

    void finishRelaunching() {
        unfreezeBounds();

        if (mPendingRelaunchCount > 0) {
            mPendingRelaunchCount--;
        } else {
            // Update keyguard flags upon finishing relaunch.
            checkKeyguardFlagsChanged();
        }
    }

    void clearRelaunching() {
        if (mPendingRelaunchCount == 0) {
            return;
        }
        unfreezeBounds();
        mPendingRelaunchCount = 0;
    }

    /**
     * Returns true if the new child window we are adding to this token is considered greater than
     * the existing child window in this token in terms of z-order.
     */
    @Override
    protected boolean isFirstChildWindowGreaterThanSecond(WindowState newWindow,
            WindowState existingWindow) {
        final int type1 = newWindow.mAttrs.type;
        final int type2 = existingWindow.mAttrs.type;

        // Base application windows should be z-ordered BELOW all other windows in the app token.
        if (type1 == TYPE_BASE_APPLICATION && type2 != TYPE_BASE_APPLICATION) {
            return false;
        } else if (type1 != TYPE_BASE_APPLICATION && type2 == TYPE_BASE_APPLICATION) {
            return true;
        }

        // Starting windows should be z-ordered ABOVE all other windows in the app token.
        if (type1 == TYPE_APPLICATION_STARTING && type2 != TYPE_APPLICATION_STARTING) {
            return true;
        } else if (type1 != TYPE_APPLICATION_STARTING && type2 == TYPE_APPLICATION_STARTING) {
            return false;
        }

        // Otherwise the new window is greater than the existing window.
        return true;
    }

    @Override
    void addWindow(WindowState w) {
        super.addWindow(w);

        boolean gotReplacementWindow = false;
        for (int i = mChildren.size() - 1; i >= 0; i--) {
            final WindowState candidate = mChildren.get(i);
            gotReplacementWindow |= candidate.setReplacementWindowIfNeeded(w);
        }

        // if we got a replacement window, reset the timeout to give drawing more time
        if (gotReplacementWindow) {
            mService.scheduleWindowReplacementTimeouts(this);
        }
        checkKeyguardFlagsChanged();
    }

    @Override
    void removeChild(WindowState child) {
        super.removeChild(child);
        checkKeyguardFlagsChanged();
    }

    private boolean waitingForReplacement() {
        for (int i = mChildren.size() - 1; i >= 0; i--) {
            final WindowState candidate = mChildren.get(i);
            if (candidate.waitingForReplacement()) {
                return true;
            }
        }
        return false;
    }

    void onWindowReplacementTimeout() {
        for (int i = mChildren.size() - 1; i >= 0; --i) {
            (mChildren.get(i)).onWindowReplacementTimeout();
        }
    }

    void reparent(Task task, int position) {
        final Task currentTask = getTask();
        if (task == currentTask) {
            throw new IllegalArgumentException(
                    "window token=" + this + " already child of task=" + currentTask);
        }

        if (currentTask.mStack != task.mStack) {
            throw new IllegalArgumentException(
                    "window token=" + this + " current task=" + currentTask
                        + " belongs to a different stack than " + task);
        }

        if (DEBUG_ADD_REMOVE) Slog.i(TAG, "reParentWindowToken: removing window token=" + this
                + " from task=" + currentTask);
        final DisplayContent prevDisplayContent = getDisplayContent();

        mReparenting = true;

        getParent().removeChild(this);
        task.addChild(this, position);

        mReparenting = false;

        // Relayout display(s).
        final DisplayContent displayContent = task.getDisplayContent();
        displayContent.setLayoutNeeded();
        if (prevDisplayContent != displayContent) {
            onDisplayChanged(displayContent);
            prevDisplayContent.setLayoutNeeded();
        }
    }

    /**
     * Freezes the task bounds. The size of this task reported the app will be fixed to the bounds
     * freezed by {@link Task#prepareFreezingBounds} until {@link #unfreezeBounds} gets called, even
     * if they change in the meantime. If the bounds are already frozen, the bounds will be frozen
     * with a queue.
     */
    private void freezeBounds() {
        final Task task = getTask();
        mFrozenBounds.offer(new Rect(task.mPreparedFrozenBounds));

        if (task.mPreparedFrozenMergedConfig.equals(Configuration.EMPTY)) {
            // We didn't call prepareFreezingBounds on the task, so use the current value.
            mFrozenMergedConfig.offer(new Configuration(task.getConfiguration()));
        } else {
            mFrozenMergedConfig.offer(new Configuration(task.mPreparedFrozenMergedConfig));
        }
        // Calling unset() to make it equal to Configuration.EMPTY.
        task.mPreparedFrozenMergedConfig.unset();
    }

    /**
     * Unfreezes the previously frozen bounds. See {@link #freezeBounds}.
     */
    private void unfreezeBounds() {
        if (mFrozenBounds.isEmpty()) {
            return;
        }
        mFrozenBounds.remove();
        if (!mFrozenMergedConfig.isEmpty()) {
            mFrozenMergedConfig.remove();
        }
        for (int i = mChildren.size() - 1; i >= 0; i--) {
            final WindowState win = mChildren.get(i);
            win.onUnfreezeBounds();
        }
        mService.mWindowPlacerLocked.performSurfacePlacement();
    }

    void setAppLayoutChanges(int changes, String reason) {
        if (!mChildren.isEmpty()) {
            final DisplayContent dc = getDisplayContent();
            dc.pendingLayoutChanges |= changes;
            if (DEBUG_LAYOUT_REPEATS) {
                mService.mWindowPlacerLocked.debugLayoutRepeats(reason, dc.pendingLayoutChanges);
            }
        }
    }

    void removeReplacedWindowIfNeeded(WindowState replacement) {
        for (int i = mChildren.size() - 1; i >= 0; i--) {
            final WindowState win = mChildren.get(i);
            if (win.removeReplacedWindowIfNeeded(replacement)) {
                return;
            }
        }
    }

    void startFreezingScreen() {
        if (DEBUG_ORIENTATION) logWithStack(TAG, "Set freezing of " + appToken + ": hidden="
                + isHidden() + " freezing=" + mFreezingScreen + " hiddenRequested="
                + hiddenRequested);
        if (!hiddenRequested) {
            if (!mFreezingScreen) {
                mFreezingScreen = true;
                mService.registerAppFreezeListener(this);
                mService.mAppsFreezingScreen++;
                if (mService.mAppsFreezingScreen == 1) {
                    mService.startFreezingDisplayLocked(false, 0, 0, getDisplayContent());
                    mService.mH.removeMessages(H.APP_FREEZE_TIMEOUT);
                    mService.mH.sendEmptyMessageDelayed(H.APP_FREEZE_TIMEOUT, 2000);
                }
            }
            final int count = mChildren.size();
            for (int i = 0; i < count; i++) {
                final WindowState w = mChildren.get(i);
                w.onStartFreezingScreen();
            }
        }
    }

    void stopFreezingScreen(boolean unfreezeSurfaceNow, boolean force) {
        if (!mFreezingScreen) {
            return;
        }
        if (DEBUG_ORIENTATION) Slog.v(TAG_WM, "Clear freezing of " + this + " force=" + force);
        final int count = mChildren.size();
        boolean unfrozeWindows = false;
        for (int i = 0; i < count; i++) {
            final WindowState w = mChildren.get(i);
            unfrozeWindows |= w.onStopFreezingScreen();
        }
        if (force || unfrozeWindows) {
            if (DEBUG_ORIENTATION) Slog.v(TAG_WM, "No longer freezing: " + this);
            mFreezingScreen = false;
            mService.unregisterAppFreezeListener(this);
            mService.mAppsFreezingScreen--;
            mService.mLastFinishedFreezeSource = this;
        }
        if (unfreezeSurfaceNow) {
            if (unfrozeWindows) {
                mService.mWindowPlacerLocked.performSurfacePlacement();
            }
            mService.stopFreezingDisplayLocked();
        }
    }

    @Override
    public void onAppFreezeTimeout() {
        Slog.w(TAG_WM, "Force clearing freeze: " + this);
        stopFreezingScreen(true, true);
    }

    boolean transferStartingWindow(IBinder transferFrom) {
        final AppWindowToken fromToken = getDisplayContent().getAppWindowToken(transferFrom);
        if (fromToken == null) {
            return false;
        }

        final WindowState tStartingWindow = fromToken.startingWindow;
        if (tStartingWindow != null && fromToken.startingSurface != null) {
            // In this case, the starting icon has already been displayed, so start
            // letting windows get shown immediately without any more transitions.
            mService.mSkipAppTransitionAnimation = true;

            if (DEBUG_STARTING_WINDOW) Slog.v(TAG_WM, "Moving existing starting " + tStartingWindow
                    + " from " + fromToken + " to " + this);

            final long origId = Binder.clearCallingIdentity();
            try {
                // Transfer the starting window over to the new token.
                startingData = fromToken.startingData;
                startingSurface = fromToken.startingSurface;
                startingDisplayed = fromToken.startingDisplayed;
                fromToken.startingDisplayed = false;
                startingWindow = tStartingWindow;
                reportedVisible = fromToken.reportedVisible;
                fromToken.startingData = null;
                fromToken.startingSurface = null;
                fromToken.startingWindow = null;
                fromToken.startingMoved = true;
                tStartingWindow.mToken = this;
                tStartingWindow.mAppToken = this;

                if (DEBUG_ADD_REMOVE || DEBUG_STARTING_WINDOW) Slog.v(TAG_WM,
                        "Removing starting " + tStartingWindow + " from " + fromToken);
                fromToken.removeChild(tStartingWindow);
                fromToken.postWindowRemoveStartingWindowCleanup(tStartingWindow);
                fromToken.mHiddenSetFromTransferredStartingWindow = false;
                addWindow(tStartingWindow);

                // Propagate other interesting state between the tokens. If the old token is displayed,
                // we should immediately force the new one to be displayed. If it is animating, we need
                // to move that animation to the new one.
                if (fromToken.allDrawn) {
                    allDrawn = true;
                    deferClearAllDrawn = fromToken.deferClearAllDrawn;
                }
                if (fromToken.firstWindowDrawn) {
                    firstWindowDrawn = true;
                }
                if (!fromToken.isHidden()) {
                    setHidden(false);
                    hiddenRequested = false;
                    mHiddenSetFromTransferredStartingWindow = true;
                }
                setClientHidden(fromToken.mClientHidden);

                transferAnimation(fromToken);

                // When transferring an animation, we no longer need to apply an animation to the
                // the token we transfer the animation over. Thus, remove the animation from
                // pending opening apps.
                mService.mOpeningApps.remove(this);

                mService.updateFocusedWindowLocked(
                        UPDATE_FOCUS_WILL_PLACE_SURFACES, true /*updateInputWindows*/);
                getDisplayContent().setLayoutNeeded();
                mService.mWindowPlacerLocked.performSurfacePlacement();
            } finally {
                Binder.restoreCallingIdentity(origId);
            }
            return true;
        } else if (fromToken.startingData != null) {
            // The previous app was getting ready to show a
            // starting window, but hasn't yet done so.  Steal it!
            if (DEBUG_STARTING_WINDOW) Slog.v(TAG_WM,
                    "Moving pending starting from " + fromToken + " to " + this);
            startingData = fromToken.startingData;
            fromToken.startingData = null;
            fromToken.startingMoved = true;
            if (getController() != null) {
                getController().scheduleAddStartingWindow();
            }
            return true;
        }

        // TODO: Transfer thumbnail

        return false;
    }

    boolean isLastWindow(WindowState win) {
        return mChildren.size() == 1 && mChildren.get(0) == win;
    }

    @Override
    void onAppTransitionDone() {
        sendingToBottom = false;
    }

    /**
     * We override because this class doesn't want its children affecting its reported orientation
     * in anyway.
     */
    @Override
    int getOrientation(int candidate) {
        if (candidate == SCREEN_ORIENTATION_BEHIND) {
            // Allow app to specify orientation regardless of its visibility state if the current
            // candidate want us to use orientation behind. I.e. the visible app on-top of this one
            // wants us to use the orientation of the app behind it.
            return mOrientation;
        }

        // The {@link AppWindowToken} should only specify an orientation when it is not closing or
        // going to the bottom. Allowing closing {@link AppWindowToken} to participate can lead to
        // an Activity in another task being started in the wrong orientation during the transition.
        if (!(sendingToBottom || mService.mClosingApps.contains(this))
                && (isVisible() || mService.mOpeningApps.contains(this) || isOnTop())) {
            return mOrientation;
        }

        return SCREEN_ORIENTATION_UNSET;
    }

    /** Returns the app's preferred orientation regardless of its currently visibility state. */
    int getOrientationIgnoreVisibility() {
        return mOrientation;
    }

    @Override
    void checkAppWindowsReadyToShow() {
        if (allDrawn == mLastAllDrawn) {
            return;
        }

        mLastAllDrawn = allDrawn;
        if (!allDrawn) {
            return;
        }

        // The token has now changed state to having all windows shown...  what to do, what to do?
        if (mFreezingScreen) {
            showAllWindowsLocked();
            stopFreezingScreen(false, true);
            if (DEBUG_ORIENTATION) Slog.i(TAG,
                    "Setting mOrientationChangeComplete=true because wtoken " + this
                    + " numInteresting=" + mNumInterestingWindows + " numDrawn=" + mNumDrawnWindows);
            // This will set mOrientationChangeComplete and cause a pass through layout.
            setAppLayoutChanges(FINISH_LAYOUT_REDO_WALLPAPER,
                    "checkAppWindowsReadyToShow: freezingScreen");
        } else {
            setAppLayoutChanges(FINISH_LAYOUT_REDO_ANIM, "checkAppWindowsReadyToShow");

            // We can now show all of the drawn windows!
            if (!mService.mOpeningApps.contains(this)) {
                showAllWindowsLocked();
            }
        }
    }

    /**
     * Returns whether the drawn window states of this {@link AppWindowToken} has considered every
     * child {@link WindowState}. A child is considered if it has been passed into
     * {@link #updateDrawnWindowStates(WindowState)} after being added. This is used to determine
     * whether states, such as {@code allDrawn}, can be set, which relies on state variables such as
     * {@code mNumInterestingWindows}, which depend on all {@link WindowState}s being considered.
     *
     * @return {@code true} If all children have been considered, {@code false}.
     */
    private boolean allDrawnStatesConsidered() {
        for (int i = mChildren.size() - 1; i >= 0; --i) {
            final WindowState child = mChildren.get(i);
            if (child.mightAffectAllDrawn() && !child.getDrawnStateEvaluated()) {
                return false;
            }
        }
        return true;
    }

    /**
     *  Determines if the token has finished drawing. This should only be called from
     *  {@link DisplayContent#applySurfaceChangesTransaction}
     */
    void updateAllDrawn() {
        if (!allDrawn) {
            // Number of drawn windows can be less when a window is being relaunched, wait for
            // all windows to be launched and drawn for this token be considered all drawn.
            final int numInteresting = mNumInterestingWindows;

            // We must make sure that all present children have been considered (determined by
            // {@link #allDrawnStatesConsidered}) before evaluating whether everything has been
            // drawn.
            if (numInteresting > 0 && allDrawnStatesConsidered()
                    && mNumDrawnWindows >= numInteresting && !isRelaunching()) {
                if (DEBUG_VISIBILITY) Slog.v(TAG, "allDrawn: " + this
                        + " interesting=" + numInteresting + " drawn=" + mNumDrawnWindows);
                allDrawn = true;
                // Force an additional layout pass where
                // WindowStateAnimator#commitFinishDrawingLocked() will call performShowLocked().
                if (mDisplayContent != null) {
                    mDisplayContent.setLayoutNeeded();
                }
                mService.mH.obtainMessage(NOTIFY_ACTIVITY_DRAWN, token).sendToTarget();

                // Notify the pinned stack upon all windows drawn. If there was an animation in
                // progress then this signal will resume that animation.
                final TaskStack pinnedStack = mDisplayContent.getPinnedStack();
                if (pinnedStack != null) {
                    pinnedStack.onAllWindowsDrawn();
                }
            }
        }
    }

    /**
     * Updated this app token tracking states for interesting and drawn windows based on the window.
     *
     * @return Returns true if the input window is considered interesting and drawn while all the
     *         windows in this app token where not considered drawn as of the last pass.
     */
    boolean updateDrawnWindowStates(WindowState w) {
        w.setDrawnStateEvaluated(true /*evaluated*/);

        if (DEBUG_STARTING_WINDOW_VERBOSE && w == startingWindow) {
            Slog.d(TAG, "updateWindows: starting " + w + " isOnScreen=" + w.isOnScreen()
                    + " allDrawn=" + allDrawn + " freezingScreen=" + mFreezingScreen);
        }

        if (allDrawn && !mFreezingScreen) {
            return false;
        }

        if (mLastTransactionSequence != mService.mTransactionSequence) {
            mLastTransactionSequence = mService.mTransactionSequence;
            mNumInterestingWindows = mNumDrawnWindows = 0;
            startingDisplayed = false;
        }

        final WindowStateAnimator winAnimator = w.mWinAnimator;

        boolean isInterestingAndDrawn = false;

        if (!allDrawn && w.mightAffectAllDrawn()) {
            if (DEBUG_VISIBILITY || DEBUG_ORIENTATION) {
                Slog.v(TAG, "Eval win " + w + ": isDrawn=" + w.isDrawnLw()
                        + ", isAnimationSet=" + isSelfAnimating());
                if (!w.isDrawnLw()) {
                    Slog.v(TAG, "Not displayed: s=" + winAnimator.mSurfaceController
                            + " pv=" + w.mPolicyVisibility
                            + " mDrawState=" + winAnimator.drawStateToString()
                            + " ph=" + w.isParentWindowHidden() + " th=" + hiddenRequested
                            + " a=" + isSelfAnimating());
                }
            }

            if (w != startingWindow) {
                if (w.isInteresting()) {
                    mNumInterestingWindows++;
                    if (w.isDrawnLw()) {
                        mNumDrawnWindows++;

                        if (DEBUG_VISIBILITY || DEBUG_ORIENTATION) Slog.v(TAG, "tokenMayBeDrawn: "
                                + this + " w=" + w + " numInteresting=" + mNumInterestingWindows
                                + " freezingScreen=" + mFreezingScreen
                                + " mAppFreezing=" + w.mAppFreezing);

                        isInterestingAndDrawn = true;
                    }
                }
            } else if (w.isDrawnLw()) {
                if (getController() != null) {
                    getController().reportStartingWindowDrawn();
                }
                startingDisplayed = true;
            }
        }

        return isInterestingAndDrawn;
    }

    @Override
    boolean forAllWindows(ToBooleanFunction<WindowState> callback, boolean traverseTopToBottom) {
        // For legacy reasons we process the TaskStack.mExitingAppTokens first in DisplayContent
        // before the non-exiting app tokens. So, we skip the exiting app tokens here.
        // TODO: Investigate if we need to continue to do this or if we can just process them
        // in-order.
        if (mIsExiting && !waitingForReplacement()) {
            return false;
        }
        return forAllWindowsUnchecked(callback, traverseTopToBottom);
    }

    boolean forAllWindowsUnchecked(ToBooleanFunction<WindowState> callback,
            boolean traverseTopToBottom) {
        return super.forAllWindows(callback, traverseTopToBottom);
    }

    @Override
    AppWindowToken asAppWindowToken() {
        // I am an app window token!
        return this;
    }

    @Override
    boolean fillsParent() {
        return mFillsParent;
    }

    void setFillsParent(boolean fillsParent) {
        mFillsParent = fillsParent;
    }

    boolean containsDismissKeyguardWindow() {
        // Window state is transient during relaunch. We are not guaranteed to be frozen during the
        // entirety of the relaunch.
        if (isRelaunching()) {
            return mLastContainsDismissKeyguardWindow;
        }

        for (int i = mChildren.size() - 1; i >= 0; i--) {
            if ((mChildren.get(i).mAttrs.flags & FLAG_DISMISS_KEYGUARD) != 0) {
                return true;
            }
        }
        return false;
    }

    boolean containsShowWhenLockedWindow() {
        // When we are relaunching, it is possible for us to be unfrozen before our previous
        // windows have been added back. Using the cached value ensures that our previous
        // showWhenLocked preference is honored until relaunching is complete.
        if (isRelaunching()) {
            return mLastContainsShowWhenLockedWindow;
        }

        for (int i = mChildren.size() - 1; i >= 0; i--) {
            if ((mChildren.get(i).mAttrs.flags & FLAG_SHOW_WHEN_LOCKED) != 0) {
                return true;
            }
        }

        return false;
    }

    void checkKeyguardFlagsChanged() {
        final boolean containsDismissKeyguard = containsDismissKeyguardWindow();
        final boolean containsShowWhenLocked = containsShowWhenLockedWindow();
        if (containsDismissKeyguard != mLastContainsDismissKeyguardWindow
                || containsShowWhenLocked != mLastContainsShowWhenLockedWindow) {
            mService.notifyKeyguardFlagsChanged(null /* callback */);
        }
        mLastContainsDismissKeyguardWindow = containsDismissKeyguard;
        mLastContainsShowWhenLockedWindow = containsShowWhenLocked;
    }

    WindowState getImeTargetBelowWindow(WindowState w) {
        final int index = mChildren.indexOf(w);
        if (index > 0) {
            final WindowState target = mChildren.get(index - 1);
            if (target.canBeImeTarget()) {
                return target;
            }
        }
        return null;
    }

    int getLowestAnimLayer() {
        for (int i = 0; i < mChildren.size(); i++) {
            final WindowState w = mChildren.get(i);
            if (w.mRemoved) {
                continue;
            }
            return w.mWinAnimator.mAnimLayer;
        }
        return Integer.MAX_VALUE;
    }

    WindowState getHighestAnimLayerWindow(WindowState currentTarget) {
        WindowState candidate = null;
        for (int i = mChildren.indexOf(currentTarget); i >= 0; i--) {
            final WindowState w = mChildren.get(i);
            if (w.mRemoved) {
                continue;
            }
            if (candidate == null || w.mWinAnimator.mAnimLayer >
                    candidate.mWinAnimator.mAnimLayer) {
                candidate = w;
            }
        }
        return candidate;
    }

    /**
     * See {@link Activity#setDisablePreviewScreenshots}.
     */
    void setDisablePreviewScreenshots(boolean disable) {
        mDisablePreviewScreenshots = disable;
    }

    /**
     * Sets whether the current launch can turn the screen on. See {@link #canTurnScreenOn()}
     */
    void setCanTurnScreenOn(boolean canTurnScreenOn) {
        mCanTurnScreenOn = canTurnScreenOn;
    }

    /**
     * Indicates whether the current launch can turn the screen on. This is to prevent multiple
     * relayouts from turning the screen back on. The screen should only turn on at most
     * once per activity resume.
     *
     * @return true if the screen can be turned on.
     */
    boolean canTurnScreenOn() {
        return mCanTurnScreenOn;
    }

    /**
     * Retrieves whether we'd like to generate a snapshot that's based solely on the theme. This is
     * the case when preview screenshots are disabled {@link #setDisablePreviewScreenshots} or when
     * we can't take a snapshot for other reasons, for example, if we have a secure window.
     *
     * @return True if we need to generate an app theme snapshot, false if we'd like to take a real
     *         screenshot.
     */
    boolean shouldUseAppThemeSnapshot() {
        return mDisablePreviewScreenshots || forAllWindows(w -> (w.mAttrs.flags & FLAG_SECURE) != 0,
                true /* topToBottom */);
    }

    @Override
    public SurfaceControl.Builder makeAnimationLeash() {
        return super.makeAnimationLeash()
                .setParent(getAppAnimationLayer());
    }

    boolean applyAnimationLocked(WindowManager.LayoutParams lp, int transit, boolean enter,
            boolean isVoiceInteraction) {

        if (mService.mDisableTransitionAnimation) {
            if (DEBUG_APP_TRANSITIONS || DEBUG_ANIM) {
                Slog.v(TAG_WM, "applyAnimation: transition animation is disabled. atoken=" + this);
            }
            cancelAnimation();
            return false;
        }

        // Only apply an animation if the display isn't frozen. If it is frozen, there is no reason
        // to animate and it can cause strange artifacts when we unfreeze the display if some
        // different animation is running.
        Trace.traceBegin(TRACE_TAG_WINDOW_MANAGER, "AWT#applyAnimationLocked");
        if (okToAnimate()) {
            final Animation a = loadAnimation(lp, transit, enter, isVoiceInteraction);
            if (a != null) {
                final TaskStack stack = getStack();
                mTmpPoint.set(0, 0);
                if (stack != null) {
                    stack.getRelativePosition(mTmpPoint);
                }
                final AnimationAdapter adapter = new LocalAnimationAdapter(
                        new WindowAnimationSpec(a, mTmpPoint,
                                mService.mAppTransition.canSkipFirstFrame()),
                        mService.mSurfaceAnimationRunner);
                if (a.getZAdjustment() == Animation.ZORDER_TOP) {
                    mNeedsZBoost = true;
                }
                startAnimation(getPendingTransaction(), adapter, !isVisible());
                mTransit = transit;
                mTransitFlags = mService.mAppTransition.getTransitFlags();
                // TODO: Skip first frame and app stack clip mode.
            }
        } else {
            cancelAnimation();
        }
        Trace.traceEnd(TRACE_TAG_WINDOW_MANAGER);

        return isReallyAnimating();
    }

    private Animation loadAnimation(WindowManager.LayoutParams lp, int transit, boolean enter,
            boolean isVoiceInteraction) {
        final DisplayContent displayContent = getTask().getDisplayContent();
        final DisplayInfo displayInfo = displayContent.getDisplayInfo();
        final int width = displayInfo.appWidth;
        final int height = displayInfo.appHeight;
        if (DEBUG_APP_TRANSITIONS || DEBUG_ANIM) Slog.v(TAG_WM,
                "applyAnimation: atoken=" + this);

        // Determine the visible rect to calculate the thumbnail clip
        final WindowState win = findMainWindow();
        final Rect frame = new Rect(0, 0, width, height);
        final Rect displayFrame = new Rect(0, 0,
                displayInfo.logicalWidth, displayInfo.logicalHeight);
        final Rect insets = new Rect();
        final Rect stableInsets = new Rect();
        Rect surfaceInsets = null;
        final boolean freeform = win != null && win.inFreeformWindowingMode();
        if (win != null) {
            // Containing frame will usually cover the whole screen, including dialog windows.
            // For freeform workspace windows it will not cover the whole screen and it also
            // won't exactly match the final freeform window frame (e.g. when overlapping with
            // the status bar). In that case we need to use the final frame.
            if (freeform) {
                frame.set(win.mFrame);
            } else {
                frame.set(win.mContainingFrame);
            }
            surfaceInsets = win.getAttrs().surfaceInsets;
            insets.set(win.mContentInsets);
            stableInsets.set(win.mStableInsets);
        }

        if (mLaunchTaskBehind) {
            // Differentiate the two animations. This one which is briefly on the screen
            // gets the !enter animation, and the other activity which remains on the
            // screen gets the enter animation. Both appear in the mOpeningApps set.
            enter = false;
        }
        if (DEBUG_APP_TRANSITIONS) Slog.d(TAG_WM, "Loading animation for app transition."
                + " transit=" + AppTransition.appTransitionToString(transit) + " enter=" + enter
                + " frame=" + frame + " insets=" + insets + " surfaceInsets=" + surfaceInsets);
        final Configuration displayConfig = displayContent.getConfiguration();
        final Animation a = mService.mAppTransition.loadAnimation(lp, transit, enter,
                displayConfig.uiMode, displayConfig.orientation, frame, displayFrame, insets,
                surfaceInsets, stableInsets, isVoiceInteraction, freeform, getTask().mTaskId);
        if (a != null) {
            if (DEBUG_ANIM) logWithStack(TAG, "Loaded animation " + a + " for " + this);
            final int containingWidth = frame.width();
            final int containingHeight = frame.height();
            a.initialize(containingWidth, containingHeight, width, height);
            a.scaleCurrentDuration(mService.getTransitionAnimationScaleLocked());
        }
        return a;
    }

    @Override
    protected void setLayer(Transaction t, int layer) {
        if (!mSurfaceAnimator.hasLeash()) {
            t.setLayer(mSurfaceControl, layer);
        }
    }

    @Override
    protected void setRelativeLayer(Transaction t, SurfaceControl relativeTo, int layer) {
        if (!mSurfaceAnimator.hasLeash()) {
            t.setRelativeLayer(mSurfaceControl, relativeTo, layer);
        }
    }

    @Override
    protected void reparentSurfaceControl(Transaction t, SurfaceControl newParent) {
        if (!mSurfaceAnimator.hasLeash()) {
            t.reparent(mSurfaceControl, newParent.getHandle());
        }
    }

    @Override
    public void onAnimationLeashCreated(Transaction t, SurfaceControl leash) {

        // The leash is parented to the animation layer. We need to preserve the z-order by using
        // the prefix order index, but we boost if necessary.
        int layer = getPrefixOrderIndex();
        if (mNeedsZBoost) {
            layer += Z_BOOST_BASE;
        }
        leash.setLayer(layer);
    }

    /**
     * This must be called while inside a transaction.
     */
    void showAllWindowsLocked() {
        forAllWindows(windowState -> {
            if (DEBUG_VISIBILITY) Slog.v(TAG, "performing show on: " + windowState);
            windowState.performShowLocked();
        }, false /* traverseTopToBottom */);
    }

    @Override
    protected void onAnimationFinished() {
        super.onAnimationFinished();

        mTransit = TRANSIT_UNSET;
        mTransitFlags = 0;
        mNeedsZBoost = false;

        setAppLayoutChanges(FINISH_LAYOUT_REDO_ANIM | FINISH_LAYOUT_REDO_WALLPAPER,
                "AppWindowToken");

        clearThumbnail();

        if (mService.mInputMethodTarget != null && mService.mInputMethodTarget.mAppToken == this) {
            getDisplayContent().computeImeTarget(true /* updateImeTarget */);
        }

        if (DEBUG_ANIM) Slog.v(TAG, "Animation done in " + this
                + ": reportedVisible=" + reportedVisible
                + " okToDisplay=" + okToDisplay()
                + " okToAnimate=" + okToAnimate()
                + " startingDisplayed=" + startingDisplayed);

        // WindowState.onExitAnimationDone might modify the children list, so make a copy and then
        // traverse the copy.
        final ArrayList<WindowState> children = new ArrayList<>(mChildren);
        children.forEach(WindowState::onExitAnimationDone);

        mService.mAppTransition.notifyAppTransitionFinishedLocked(token);
        scheduleAnimation();
    }

    @Override
    boolean isAppAnimating() {
        return isSelfAnimating();
    }

    @Override
    boolean isSelfAnimating() {
        // If we are about to start a transition, we also need to be considered animating.
        return isWaitingForTransitionStart() || isReallyAnimating();
    }

    /**
     * @return True if and only if we are actually running an animation. Note that
     *         {@link #isSelfAnimating} also returns true if we are waiting for an animation to
     *         start.
     */
    private boolean isReallyAnimating() {
        return super.isSelfAnimating();
    }

    @Override
    void cancelAnimation() {
        super.cancelAnimation();
        clearThumbnail();
    }

    boolean isWaitingForTransitionStart() {
        return mService.mAppTransition.isTransitionSet()
                && (mService.mOpeningApps.contains(this) || mService.mClosingApps.contains(this));
    }

    public int getTransit() {
        return mTransit;
    }

    int getTransitFlags() {
        return mTransitFlags;
    }

    void attachThumbnailAnimation() {
        if (!isReallyAnimating()) {
            return;
        }
        final int taskId = getTask().mTaskId;
        final GraphicBuffer thumbnailHeader =
                mService.mAppTransition.getAppTransitionThumbnailHeader(taskId);
        if (thumbnailHeader == null) {
            if (DEBUG_APP_TRANSITIONS) Slog.d(TAG, "No thumbnail header bitmap for: " + taskId);
            return;
        }
        clearThumbnail();
        mThumbnail = new AppWindowThumbnail(getPendingTransaction(), this, thumbnailHeader);
        mThumbnail.startAnimation(getPendingTransaction(), loadThumbnailAnimation(thumbnailHeader));
    }

    private Animation loadThumbnailAnimation(GraphicBuffer thumbnailHeader) {
        final DisplayInfo displayInfo = mDisplayContent.getDisplayInfo();

        // If this is a multi-window scenario, we use the windows frame as
        // destination of the thumbnail header animation. If this is a full screen
        // window scenario, we use the whole display as the target.
        WindowState win = findMainWindow();
        Rect appRect = win != null ? win.getContentFrameLw() :
                new Rect(0, 0, displayInfo.appWidth, displayInfo.appHeight);
        Rect insets = win != null ? win.mContentInsets : null;
        final Configuration displayConfig = mDisplayContent.getConfiguration();
        return mService.mAppTransition.createThumbnailAspectScaleAnimationLocked(
                appRect, insets, thumbnailHeader, getTask().mTaskId, displayConfig.uiMode,
                displayConfig.orientation);
    }

    private void clearThumbnail() {
        if (mThumbnail == null) {
            return;
        }
        mThumbnail.destroy();
        mThumbnail = null;
    }

    @Override
    void dump(PrintWriter pw, String prefix, boolean dumpAll) {
        super.dump(pw, prefix, dumpAll);
        if (appToken != null) {
            pw.println(prefix + "app=true mVoiceInteraction=" + mVoiceInteraction);
        }
        pw.print(prefix); pw.print("task="); pw.println(getTask());
        pw.print(prefix); pw.print(" mFillsParent="); pw.print(mFillsParent);
                pw.print(" mOrientation="); pw.println(mOrientation);
        pw.println(prefix + "hiddenRequested=" + hiddenRequested + " mClientHidden=" + mClientHidden
            + ((mDeferHidingClient) ? " mDeferHidingClient=" + mDeferHidingClient : "")
            + " reportedDrawn=" + reportedDrawn + " reportedVisible=" + reportedVisible);
        if (paused) {
            pw.print(prefix); pw.print("paused="); pw.println(paused);
        }
        if (mAppStopped) {
            pw.print(prefix); pw.print("mAppStopped="); pw.println(mAppStopped);
        }
        if (mNumInterestingWindows != 0 || mNumDrawnWindows != 0
                || allDrawn || mLastAllDrawn) {
            pw.print(prefix); pw.print("mNumInterestingWindows=");
                    pw.print(mNumInterestingWindows);
                    pw.print(" mNumDrawnWindows="); pw.print(mNumDrawnWindows);
                    pw.print(" inPendingTransaction="); pw.print(inPendingTransaction);
                    pw.print(" allDrawn="); pw.print(allDrawn);
                    pw.print(" lastAllDrawn="); pw.print(mLastAllDrawn);
                    pw.println(")");
        }
        if (inPendingTransaction) {
            pw.print(prefix); pw.print("inPendingTransaction=");
                    pw.println(inPendingTransaction);
        }
        if (startingData != null || removed || firstWindowDrawn || mIsExiting) {
            pw.print(prefix); pw.print("startingData="); pw.print(startingData);
                    pw.print(" removed="); pw.print(removed);
                    pw.print(" firstWindowDrawn="); pw.print(firstWindowDrawn);
                    pw.print(" mIsExiting="); pw.println(mIsExiting);
        }
        if (startingWindow != null || startingSurface != null
                || startingDisplayed || startingMoved || mHiddenSetFromTransferredStartingWindow) {
            pw.print(prefix); pw.print("startingWindow="); pw.print(startingWindow);
                    pw.print(" startingSurface="); pw.print(startingSurface);
                    pw.print(" startingDisplayed="); pw.print(startingDisplayed);
                    pw.print(" startingMoved="); pw.print(startingMoved);
                    pw.println(" mHiddenSetFromTransferredStartingWindow="
                            + mHiddenSetFromTransferredStartingWindow);
        }
        if (!mFrozenBounds.isEmpty()) {
            pw.print(prefix); pw.print("mFrozenBounds="); pw.println(mFrozenBounds);
            pw.print(prefix); pw.print("mFrozenMergedConfig="); pw.println(mFrozenMergedConfig);
        }
        if (mPendingRelaunchCount != 0) {
            pw.print(prefix); pw.print("mPendingRelaunchCount="); pw.println(mPendingRelaunchCount);
        }
        if (getController() != null) {
            pw.print(prefix); pw.print("controller="); pw.println(getController());
        }
        if (mRemovingFromDisplay) {
            pw.println(prefix + "mRemovingFromDisplay=" + mRemovingFromDisplay);
        }
    }

    @Override
    void setHidden(boolean hidden) {
        super.setHidden(hidden);
        scheduleAnimation();
    }

    @Override
    void prepareSurfaces() {
        // isSelfAnimating also returns true when we are about to start a transition, so we need
        // to check super here.
        final boolean reallyAnimating = super.isSelfAnimating();
        final boolean show = !isHidden() || reallyAnimating;
        if (show && !mLastSurfaceShowing) {
            mPendingTransaction.show(mSurfaceControl);
        } else if (!show && mLastSurfaceShowing) {
            mPendingTransaction.hide(mSurfaceControl);
        }
        if (mThumbnail != null) {
            mThumbnail.setShowing(mPendingTransaction, show);
        }
        mLastSurfaceShowing = show;
        super.prepareSurfaces();
    }

    boolean isFreezingScreen() {
        return mFreezingScreen;
    }

    @Override
    boolean needsZBoost() {
        return mNeedsZBoost || super.needsZBoost();
    }

    @CallSuper
    @Override
    public void writeToProto(ProtoOutputStream proto, long fieldId, boolean trim) {
        final long token = proto.start(fieldId);
        writeNameToProto(proto, NAME);
        super.writeToProto(proto, WINDOW_TOKEN, trim);
        proto.end(token);
    }

    void writeNameToProto(ProtoOutputStream proto, long fieldId) {
        if (appToken == null) {
            return;
        }
        try {
            proto.write(fieldId, appToken.getName());
        } catch (RemoteException e) {
            // This shouldn't happen, but in this case fall back to outputting nothing
            Slog.e(TAG, e.toString());
        }
    }

    @Override
    public String toString() {
        if (stringName == null) {
            StringBuilder sb = new StringBuilder();
            sb.append("AppWindowToken{");
            sb.append(Integer.toHexString(System.identityHashCode(this)));
            sb.append(" token="); sb.append(token); sb.append('}');
            stringName = sb.toString();
        }
        return stringName + ((mIsExiting) ? " mIsExiting=" : "");
    }
}