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

/*
 * Copyright (C) 2019 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.Manifest.permission.MANAGE_ACTIVITY_STACKS;
import static android.app.WindowConfiguration.WINDOWING_MODE_MULTI_WINDOW;
import static android.app.WindowConfiguration.WINDOWING_MODE_PINNED;
import static android.app.WindowConfiguration.WINDOWING_MODE_SPLIT_SCREEN_PRIMARY;
import static android.app.WindowConfiguration.WINDOWING_MODE_SPLIT_SCREEN_SECONDARY;

import static com.android.server.wm.ActivityStackSupervisor.PRESERVE_WINDOWS;
import static com.android.server.wm.Task.FLAG_FORCE_HIDDEN_FOR_TASK_ORG;
import static com.android.server.wm.WindowContainer.POSITION_BOTTOM;
import static com.android.server.wm.WindowContainer.POSITION_TOP;

import android.annotation.Nullable;
import android.app.ActivityManager.RunningTaskInfo;
import android.app.WindowConfiguration;
import android.content.pm.ActivityInfo;
import android.content.res.Configuration;
import android.graphics.Rect;
import android.os.Binder;
import android.os.IBinder;
import android.os.RemoteException;
import android.util.ArraySet;
import android.util.Slog;
import android.view.SurfaceControl;
import android.window.ITaskOrganizerController;
import android.window.ITaskOrganizer;
import android.window.IWindowContainer;
import android.window.WindowContainerTransaction;

import com.android.internal.util.ArrayUtils;
import com.android.internal.util.function.pooled.PooledConsumer;
import com.android.internal.util.function.pooled.PooledLambda;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.WeakHashMap;

/**
 * Stores the TaskOrganizers associated with a given windowing mode and
 * their associated state.
 */
class TaskOrganizerController extends ITaskOrganizerController.Stub
    implements BLASTSyncEngine.TransactionReadyListener {
    private static final String TAG = "TaskOrganizerController";

    /** Flag indicating that an applied transaction may have effected lifecycle */
    private static final int TRANSACT_EFFECTS_CLIENT_CONFIG = 1;
    private static final int TRANSACT_EFFECTS_LIFECYCLE = 1 << 1;

    /**
     * Masks specifying which configurations task-organizers can control. Incoming transactions
     * will be filtered to only include these.
     */
    private static final int CONTROLLABLE_CONFIGS = ActivityInfo.CONFIG_WINDOW_CONFIGURATION
                | ActivityInfo.CONFIG_SMALLEST_SCREEN_SIZE | ActivityInfo.CONFIG_SCREEN_SIZE;
    private static final int CONTROLLABLE_WINDOW_CONFIGS = WindowConfiguration.WINDOW_CONFIG_BOUNDS
                | WindowConfiguration.WINDOW_CONFIG_APP_BOUNDS;
    /**
     * Masks specifying which configurations are important to report back to an organizer when
     * changed.
     */
    private static final int REPORT_CONFIGS = CONTROLLABLE_CONFIGS;
    private static final int REPORT_WINDOW_CONFIGS = CONTROLLABLE_WINDOW_CONFIGS;

    private final WindowManagerGlobalLock mGlobalLock;

    private class DeathRecipient implements IBinder.DeathRecipient {
        int mWindowingMode;
        ITaskOrganizer mTaskOrganizer;

        DeathRecipient(ITaskOrganizer organizer, int windowingMode) {
            mTaskOrganizer = organizer;
            mWindowingMode = windowingMode;
        }

        @Override
        public void binderDied() {
            synchronized (mGlobalLock) {
                final TaskOrganizerState state =
                    mTaskOrganizerStates.get(mTaskOrganizer.asBinder());
                state.releaseTasks();
                mTaskOrganizerStates.remove(mTaskOrganizer.asBinder());
                if (mTaskOrganizersForWindowingMode.get(mWindowingMode) == mTaskOrganizer) {
                    mTaskOrganizersForWindowingMode.remove(mWindowingMode);
                }
            }
        }
    };

    class TaskOrganizerState {
        ITaskOrganizer mOrganizer;
        DeathRecipient mDeathRecipient;
        int mWindowingMode;

        ArrayList<Task> mOrganizedTasks = new ArrayList<>();

        // Save the TaskOrganizer which we replaced registration for
        // so it can be re-registered if we unregister.
        TaskOrganizerState mReplacementFor;
        boolean mDisposed = false;


        TaskOrganizerState(ITaskOrganizer organizer, int windowingMode,
                @Nullable TaskOrganizerState replacing) {
            mOrganizer = organizer;
            mDeathRecipient = new DeathRecipient(organizer, windowingMode);
            try {
                organizer.asBinder().linkToDeath(mDeathRecipient, 0);
            } catch (RemoteException e) {
                Slog.e(TAG, "TaskOrganizer failed to register death recipient");
            }
            mWindowingMode = windowingMode;
            mReplacementFor = replacing;
        }

        void addTask(Task t) {
            mOrganizedTasks.add(t);
            try {
                mOrganizer.taskAppeared(t.getTaskInfo());
            } catch (Exception e) {
                Slog.e(TAG, "Exception sending taskAppeared callback" + e);
            }
        }

        void removeTask(Task t) {
            try {
                mOrganizer.taskVanished(t.getTaskInfo());
            } catch (Exception e) {
                Slog.e(TAG, "Exception sending taskVanished callback" + e);
            }
            mOrganizedTasks.remove(t);
        }

        void dispose() {
            mDisposed = true;
            releaseTasks();
            handleReplacement();
        }

        void releaseTasks() {
            for (int i = mOrganizedTasks.size() - 1; i >= 0; i--) {
                final Task t = mOrganizedTasks.get(i);
                t.taskOrganizerDied();
                removeTask(t);
            }
        }

        void handleReplacement() {
            if (mReplacementFor != null && !mReplacementFor.mDisposed) {
                mTaskOrganizersForWindowingMode.put(mWindowingMode, mReplacementFor);
            }
        }

        void unlinkDeath() {
            mDisposed = true;
            mOrganizer.asBinder().unlinkToDeath(mDeathRecipient, 0);
        }
    };


    final HashMap<Integer, TaskOrganizerState> mTaskOrganizersForWindowingMode = new HashMap();
    final HashMap<IBinder, TaskOrganizerState> mTaskOrganizerStates = new HashMap();

    final HashMap<Integer, ITaskOrganizer> mTaskOrganizersByPendingSyncId = new HashMap();

    private final WeakHashMap<Task, RunningTaskInfo> mLastSentTaskInfos = new WeakHashMap<>();
    private final ArrayList<Task> mPendingTaskInfoChanges = new ArrayList<>();

    private final BLASTSyncEngine mBLASTSyncEngine = new BLASTSyncEngine();

    final ActivityTaskManagerService mService;

    RunningTaskInfo mTmpTaskInfo;

    TaskOrganizerController(ActivityTaskManagerService atm) {
        mService = atm;
        mGlobalLock = atm.mGlobalLock;
    }

    private void enforceStackPermission(String func) {
        mService.mAmInternal.enforceCallingPermission(MANAGE_ACTIVITY_STACKS, func);
    }

    /**
     * Register a TaskOrganizer to manage tasks as they enter the given windowing mode.
     * If there was already a TaskOrganizer for this windowing mode it will be evicted
     * but will continue to organize it's existing tasks.
     */
    @Override
    public void registerTaskOrganizer(ITaskOrganizer organizer, int windowingMode) {
        if (windowingMode != WINDOWING_MODE_PINNED
                && windowingMode != WINDOWING_MODE_SPLIT_SCREEN_PRIMARY
                && windowingMode != WINDOWING_MODE_SPLIT_SCREEN_SECONDARY
                && windowingMode != WINDOWING_MODE_MULTI_WINDOW) {
            throw new UnsupportedOperationException("As of now only Pinned/Split/Multiwindow"
                    + " windowing modes are supported for registerTaskOrganizer");
        }
        enforceStackPermission("registerTaskOrganizer()");
        final long origId = Binder.clearCallingIdentity();
        try {
            synchronized (mGlobalLock) {
                if (getTaskOrganizer(windowingMode) != null) {
                    Slog.w(TAG, "Task organizer already exists for windowing mode: "
                            + windowingMode);
                }
                final TaskOrganizerState previousState =
                        mTaskOrganizersForWindowingMode.get(windowingMode);
                final TaskOrganizerState state = new TaskOrganizerState(organizer, windowingMode,
                        previousState);
                mTaskOrganizersForWindowingMode.put(windowingMode, state);
                mTaskOrganizerStates.put(organizer.asBinder(), state);

                if (previousState == null) {
                    // Only in the case where this is the root task organizer for the given
                    // windowing mode, we add report all existing tasks in that mode to the new
                    // task organizer.
                    mService.mRootWindowContainer.forAllTasks((task) -> {
                        if (task.getWindowingMode() == windowingMode) {
                            task.updateTaskOrganizerState(true /* forceUpdate */);
                        }
                    });
                }
            }
        } finally {
            Binder.restoreCallingIdentity(origId);
        }
    }

    @Override
    public void unregisterTaskOrganizer(ITaskOrganizer organizer) {
        final TaskOrganizerState state = mTaskOrganizerStates.get(organizer.asBinder());
        state.unlinkDeath();
        if (mTaskOrganizersForWindowingMode.get(state.mWindowingMode) == state) {
            mTaskOrganizersForWindowingMode.remove(state.mWindowingMode);
        }
        state.dispose();
    }

    ITaskOrganizer getTaskOrganizer(int windowingMode) {
        final TaskOrganizerState state = mTaskOrganizersForWindowingMode.get(windowingMode);
        if (state == null) {
            return null;
        }
        return state.mOrganizer;
    }

    void onTaskAppeared(ITaskOrganizer organizer, Task task) {
        final TaskOrganizerState state = mTaskOrganizerStates.get(organizer.asBinder());
        state.addTask(task);
    }

    void onTaskVanished(ITaskOrganizer organizer, Task task) {
        final TaskOrganizerState state = mTaskOrganizerStates.get(organizer.asBinder());
        state.removeTask(task);
    }

    @Override
    public RunningTaskInfo createRootTask(int displayId, int windowingMode) {
        enforceStackPermission("createRootTask()");
        final long origId = Binder.clearCallingIdentity();
        try {
            synchronized (mGlobalLock) {
                DisplayContent display = mService.mRootWindowContainer.getDisplayContent(displayId);
                if (display == null) {
                    return null;
                }
                final int nextId = display.getNextStackId();
                TaskTile tile = new TaskTile(mService, nextId, windowingMode);
                display.addTile(tile);
                RunningTaskInfo out = tile.getTaskInfo();
                mLastSentTaskInfos.put(tile, out);
                return out;
            }
        } finally {
            Binder.restoreCallingIdentity(origId);
        }
    }

    @Override
    public boolean deleteRootTask(IWindowContainer token) {
        enforceStackPermission("deleteRootTask()");
        final long origId = Binder.clearCallingIdentity();
        try {
            synchronized (mGlobalLock) {
                TaskTile tile = TaskTile.forToken(token.asBinder());
                if (tile == null) {
                    return false;
                }
                tile.removeImmediately();
                return true;
            }
        } finally {
            Binder.restoreCallingIdentity(origId);
        }
    }

    void dispatchPendingTaskInfoChanges() {
        if (mService.mWindowManager.mWindowPlacerLocked.isLayoutDeferred()) {
            return;
        }
        for (int i = 0, n = mPendingTaskInfoChanges.size(); i < n; ++i) {
            dispatchTaskInfoChanged(mPendingTaskInfoChanges.get(i), false /* force */);
        }
        mPendingTaskInfoChanges.clear();
    }

    void dispatchTaskInfoChanged(Task task, boolean force) {
        if (!force && mService.mWindowManager.mWindowPlacerLocked.isLayoutDeferred()) {
            // Defer task info reporting while layout is deferred. This is because layout defer
            // blocks tend to do lots of re-ordering which can mess up animations in receivers.
            mPendingTaskInfoChanges.remove(task);
            mPendingTaskInfoChanges.add(task);
            return;
        }
        RunningTaskInfo lastInfo = mLastSentTaskInfos.get(task);
        if (mTmpTaskInfo == null) {
            mTmpTaskInfo = new RunningTaskInfo();
        }
        mTmpTaskInfo.configuration.unset();
        task.fillTaskInfo(mTmpTaskInfo);
        boolean changed = lastInfo == null
                || mTmpTaskInfo.topActivityType != lastInfo.topActivityType
                || mTmpTaskInfo.isResizable() != lastInfo.isResizable()
                || mTmpTaskInfo.pictureInPictureParams != lastInfo.pictureInPictureParams;
        if (!changed) {
            int cfgChanges = mTmpTaskInfo.configuration.diff(lastInfo.configuration);
            final int winCfgChanges = (cfgChanges & ActivityInfo.CONFIG_WINDOW_CONFIGURATION) != 0
                    ? (int) mTmpTaskInfo.configuration.windowConfiguration.diff(
                            lastInfo.configuration.windowConfiguration,
                            true /* compareUndefined */) : 0;
            if ((winCfgChanges & REPORT_WINDOW_CONFIGS) == 0) {
                cfgChanges &= ~ActivityInfo.CONFIG_WINDOW_CONFIGURATION;
            }
            changed = (cfgChanges & REPORT_CONFIGS) != 0;
        }
        if (!(changed || force)) {
            return;
        }
        final RunningTaskInfo newInfo = mTmpTaskInfo;
        mLastSentTaskInfos.put(task, mTmpTaskInfo);
        // Since we've stored this, clean up the reference so a new one will be created next time.
        // Transferring it this way means we only have to construct new RunningTaskInfos when they
        // change.
        mTmpTaskInfo = null;

        if (task.mTaskOrganizer != null) {
            try {
                task.mTaskOrganizer.onTaskInfoChanged(newInfo);
            } catch (RemoteException e) {
            }
        }
    }

    @Override
    public IWindowContainer getImeTarget(int displayId) {
        enforceStackPermission("getImeTarget()");
        final long origId = Binder.clearCallingIdentity();
        try {
            synchronized (mGlobalLock) {
                DisplayContent dc = mService.mWindowManager.mRoot
                        .getDisplayContent(displayId);
                if (dc == null || dc.mInputMethodTarget == null) {
                    return null;
                }
                // Avoid WindowState#getRootTask() so we don't attribute system windows to a task.
                final Task task = dc.mInputMethodTarget.getTask();
                if (task == null) {
                    return null;
                }
                ActivityStack rootTask = (ActivityStack) task.getRootTask();
                final TaskTile tile = rootTask.getTile();
                if (tile != null) {
                    rootTask = tile;
                }
                return rootTask.mRemoteToken;
            }
        } finally {
            Binder.restoreCallingIdentity(origId);
        }
    }

    @Override
    public void setLaunchRoot(int displayId, @Nullable IWindowContainer tile) {
        enforceStackPermission("setLaunchRoot()");
        final long origId = Binder.clearCallingIdentity();
        try {
            synchronized (mGlobalLock) {
                DisplayContent display = mService.mRootWindowContainer.getDisplayContent(displayId);
                if (display == null) {
                    return;
                }
                TaskTile taskTile = tile == null ? null : TaskTile.forToken(tile.asBinder());
                if (taskTile == null) {
                    display.mLaunchTile = null;
                    return;
                }
                if (taskTile.getDisplay() != display) {
                    throw new RuntimeException("Can't set launch root for display " + displayId
                            + " to task on display " + taskTile.getDisplay().getDisplayId());
                }
                display.mLaunchTile = taskTile;
            }
        } finally {
            Binder.restoreCallingIdentity(origId);
        }
    }

    @Override
    public List<RunningTaskInfo> getChildTasks(IWindowContainer parent,
            @Nullable int[] activityTypes) {
        enforceStackPermission("getChildTasks()");
        final long ident = Binder.clearCallingIdentity();
        try {
            synchronized (mGlobalLock) {
                if (parent == null) {
                    throw new IllegalArgumentException("Can't get children of null parent");
                }
                final WindowContainer container = WindowContainer.fromBinder(parent.asBinder());
                if (container == null) {
                    Slog.e(TAG, "Can't get children of " + parent + " because it is not valid.");
                    return null;
                }
                // For now, only support returning children of persistent root tasks (of which the
                // only current implementation is TaskTile).
                if (!(container instanceof TaskTile)) {
                    Slog.w(TAG, "Can only get children of root tasks created via createRootTask");
                    return null;
                }
                ArrayList<RunningTaskInfo> out = new ArrayList<>();
                // Tiles aren't real parents, so we need to go through stacks on the display to
                // ensure correct ordering.
                final DisplayContent dc = container.getDisplayContent();
                for (int i = dc.getStackCount() - 1; i >= 0; --i) {
                    final ActivityStack as = dc.getStackAt(i);
                    if (as.getTile() == container) {
                        if (activityTypes != null
                                && !ArrayUtils.contains(activityTypes, as.getActivityType())) {
                            continue;
                        }
                        out.add(as.getTaskInfo());
                    }
                }
                return out;
            }
        } finally {
            Binder.restoreCallingIdentity(ident);
        }
    }

    @Override
    public List<RunningTaskInfo> getRootTasks(int displayId, @Nullable int[] activityTypes) {
        enforceStackPermission("getRootTasks()");
        final long ident = Binder.clearCallingIdentity();
        try {
            synchronized (mGlobalLock) {
                final DisplayContent dc =
                        mService.mRootWindowContainer.getDisplayContent(displayId);
                if (dc == null) {
                    throw new IllegalArgumentException("Display " + displayId + " doesn't exist");
                }
                ArrayList<RunningTaskInfo> out = new ArrayList<>();
                for (int i = dc.getStackCount() - 1; i >= 0; --i) {
                    final ActivityStack task = dc.getStackAt(i);
                    if (task.getTile() != null) {
                        // a tile is supposed to look like a parent, so don't include their
                        // "children" here. They can be accessed via getChildTasks()
                        continue;
                    }
                    if (activityTypes != null
                            && !ArrayUtils.contains(activityTypes, task.getActivityType())) {
                        continue;
                    }
                    out.add(task.getTaskInfo());
                }
                return out;
            }
        } finally {
            Binder.restoreCallingIdentity(ident);
        }
    }

    private int sanitizeAndApplyChange(WindowContainer container,
            WindowContainerTransaction.Change change) {
        if (!(container instanceof Task)) {
            throw new RuntimeException("Invalid token in task transaction");
        }
        final Task task = (Task) container;
        // The "client"-facing API should prevent bad changes; however, just in case, sanitize
        // masks here.
        final int configMask = change.getConfigSetMask() & CONTROLLABLE_CONFIGS;
        final int windowMask = change.getWindowSetMask() & CONTROLLABLE_WINDOW_CONFIGS;
        int effects = 0;
        if (configMask != 0) {
            Configuration c = new Configuration(container.getRequestedOverrideConfiguration());
            c.setTo(change.getConfiguration(), configMask, windowMask);
            container.onRequestedOverrideConfigurationChanged(c);
            // TODO(b/145675353): remove the following once we could apply new bounds to the
            // pinned stack together with its children.
            resizePinnedStackIfNeeded(container, configMask, windowMask, c);
            effects |= TRANSACT_EFFECTS_CLIENT_CONFIG;
        }
        if ((change.getChangeMask() & WindowContainerTransaction.Change.CHANGE_FOCUSABLE) != 0) {
            if (container.setFocusable(change.getFocusable())) {
                effects |= TRANSACT_EFFECTS_LIFECYCLE;
            }
        }
        if ((change.getChangeMask() & WindowContainerTransaction.Change.CHANGE_HIDDEN) != 0) {
            if (task.setForceHidden(FLAG_FORCE_HIDDEN_FOR_TASK_ORG, change.getHidden())) {
                effects |= TRANSACT_EFFECTS_LIFECYCLE;
            }
        }
        return effects;
    }

    private int sanitizeAndApplyHierarchyOp(WindowContainer container,
            WindowContainerTransaction.HierarchyOp hop) {
        if (!(container instanceof Task)) {
            throw new IllegalArgumentException("Invalid container in hierarchy op");
        }
        if (container.getDisplayContent() == null) {
            Slog.w(TAG, "Container is no longer attached: " + container);
            return 0;
        }
        if (hop.isReparent()) {
            // special case for tiles since they are "virtual" parents
            if (container instanceof ActivityStack && ((ActivityStack) container).isRootTask()) {
                ActivityStack as = (ActivityStack) container;
                TaskTile newParent = hop.getNewParent() == null ? null
                        : (TaskTile) WindowContainer.fromBinder(hop.getNewParent());
                if (as.getTile() != newParent) {
                    if (as.getTile() != null) {
                        as.getTile().removeChild(as);
                    }
                    if (newParent != null) {
                        if (!as.affectedBySplitScreenResize()) {
                            return 0;
                        }
                        newParent.addChild(as, POSITION_TOP);
                    }
                }
                if (hop.getToTop()) {
                    as.getDisplay().positionStackAtTop(as, false /* includingParents */);
                } else {
                    as.getDisplay().positionStackAtBottom(as);
                }
            } else if (container instanceof Task) {
                throw new RuntimeException("Reparenting leaf Tasks is not supported now.");
            }
        } else {
            // Ugh, of course ActivityStack has its own special reorder logic...
            if (container instanceof ActivityStack && ((ActivityStack) container).isRootTask()) {
                ActivityStack as = (ActivityStack) container;
                if (hop.getToTop()) {
                    as.getDisplay().positionStackAtTop(as, false /* includingParents */);
                } else {
                    as.getDisplay().positionStackAtBottom(as);
                }
            } else {
                container.getParent().positionChildAt(
                        hop.getToTop() ? POSITION_TOP : POSITION_BOTTOM,
                        container, false /* includingParents */);
            }
        }
        return TRANSACT_EFFECTS_LIFECYCLE;
    }

    private void resizePinnedStackIfNeeded(ConfigurationContainer container, int configMask,
            int windowMask, Configuration config) {
        if ((container instanceof ActivityStack)
                && ((configMask & ActivityInfo.CONFIG_WINDOW_CONFIGURATION) != 0)
                && ((windowMask & WindowConfiguration.WINDOW_CONFIG_BOUNDS) != 0)) {
            final ActivityStack stack = (ActivityStack) container;
            if (stack.inPinnedWindowingMode()) {
                stack.resize(config.windowConfiguration.getBounds(),
                        null /* configBounds */, PRESERVE_WINDOWS, true /* deferResume */);
            }
        }
    }

    private int applyWindowContainerChange(WindowContainer wc,
            WindowContainerTransaction.Change c) {
        int effects = sanitizeAndApplyChange(wc, c);

        final Task tr = wc.asTask();

        final SurfaceControl.Transaction t = c.getBoundsChangeTransaction();
        if (t != null) {
            tr.setMainWindowSizeChangeTransaction(t);
        }

        Rect enterPipBounds = c.getEnterPipBounds();
        if (enterPipBounds != null) {
            mService.mStackSupervisor.updatePictureInPictureMode(tr,
                    enterPipBounds, true);
        }

        final int windowingMode = c.getWindowingMode();
        if (windowingMode > -1) {
            tr.setWindowingMode(windowingMode);
        }
        final int childWindowingMode = c.getActivityWindowingMode();
        if (childWindowingMode > -1) {
            tr.setActivityWindowingMode(childWindowingMode);
        }

        return effects;
    }

    @Override
    public int applyContainerTransaction(WindowContainerTransaction t, ITaskOrganizer organizer) {
        enforceStackPermission("applyContainerTransaction()");
        int syncId = -1;
        if (t == null) {
            throw new IllegalArgumentException(
                    "Null transaction passed to applyContainerTransaction");
        }
        long ident = Binder.clearCallingIdentity();
        try {
            synchronized (mGlobalLock) {
                int effects = 0;

                /**
                 * If organizer is non-null we are looking to synchronize this transaction
                 * by collecting all the results in to a SurfaceFlinger transaction and
                 * then delivering that to the given organizers transaction ready callback.
                 * See {@link BLASTSyncEngine} for the details of the operation. But at
                 * a high level we create a sync operation with a given ID and an associated
                 * organizer. Then we notify each WindowContainer in this WindowContainer
                 * transaction that it is participating in a sync operation with that
                 * ID. Once everything is notified we tell the BLASTSyncEngine
                 * "setSyncReady" which means that we have added everything
                 * to the set. At any point after this, all the WindowContainers
                 * will eventually finish applying their changes and notify the
                 * BLASTSyncEngine which will deliver the Transaction to the organizer.
                 */
                if (organizer != null) {
                    syncId = startSyncWithOrganizer(organizer);
                }
                mService.deferWindowLayout();
                try {
                    ArraySet<WindowContainer> haveConfigChanges = new ArraySet<>();
                    Iterator<Map.Entry<IBinder, WindowContainerTransaction.Change>> entries =
                            t.getChanges().entrySet().iterator();
                    while (entries.hasNext()) {
                        final Map.Entry<IBinder, WindowContainerTransaction.Change> entry =
                                entries.next();
                        final WindowContainer wc = WindowContainer.fromBinder(entry.getKey());
                        int containerEffect = applyWindowContainerChange(wc, entry.getValue());
                        effects |= containerEffect;

                        // Lifecycle changes will trigger ensureConfig for everything.
                        if ((effects & TRANSACT_EFFECTS_LIFECYCLE) == 0
                                && (containerEffect & TRANSACT_EFFECTS_CLIENT_CONFIG) != 0) {
                            haveConfigChanges.add(wc);
                        }
                        if (syncId >= 0) {
                            mBLASTSyncEngine.addToSyncSet(syncId, wc);
                        }
                    }
                    // Hierarchy changes
                    final List<WindowContainerTransaction.HierarchyOp> hops = t.getHierarchyOps();
                    for (int i = 0, n = hops.size(); i < n; ++i) {
                        final WindowContainerTransaction.HierarchyOp hop = hops.get(i);
                        final WindowContainer wc = WindowContainer.fromBinder(hop.getContainer());
                        effects |= sanitizeAndApplyHierarchyOp(wc, hop);
                    }
                    if ((effects & TRANSACT_EFFECTS_LIFECYCLE) != 0) {
                        // Already calls ensureActivityConfig
                        mService.mRootWindowContainer.ensureActivitiesVisible(
                                null, 0, PRESERVE_WINDOWS);
                    } else if ((effects & TRANSACT_EFFECTS_CLIENT_CONFIG) != 0) {
                        final PooledConsumer f = PooledLambda.obtainConsumer(
                                ActivityRecord::ensureActivityConfiguration,
                                PooledLambda.__(ActivityRecord.class), 0,
                                false /* preserveWindow */);
                        try {
                            for (int i = haveConfigChanges.size() - 1; i >= 0; --i) {
                                final WindowContainer wc = haveConfigChanges.valueAt(i);
                                final Task task = wc.asTask();
                                final TaskTile tile = task != null ? task.asTile() : null;
                                if (tile != null) {
                                    // Special case for tile. Can't override normal forAllActivities
                                    // because it generates duplicate calls and messes up existing
                                    // code-paths.
                                    tile.forAllTileActivities(f);
                                } else {
                                    wc.forAllActivities(f);
                                }
                            }
                        } finally {
                            f.recycle();
                        }
                    }
                } finally {
                    mService.continueWindowLayout();
                    if (syncId >= 0) {
                        setSyncReady(syncId);
                    }
                }
            }
        } finally {
            Binder.restoreCallingIdentity(ident);
        }
        return syncId;
    }

    @Override
    public void transactionReady(int id, SurfaceControl.Transaction sc) {
        final ITaskOrganizer organizer = mTaskOrganizersByPendingSyncId.get(id);
        if (organizer == null) {
            Slog.e(TAG, "Got transaction complete for unexpected ID");
        }
        try {
            organizer.transactionReady(id, sc);
        } catch (RemoteException e) {
        }

        mTaskOrganizersByPendingSyncId.remove(id);
    }

    int startSyncWithOrganizer(ITaskOrganizer organizer) {
        int id = mBLASTSyncEngine.startSyncSet(this);
        mTaskOrganizersByPendingSyncId.put(id, organizer);
        return id;
    }

    void setSyncReady(int id) {
        mBLASTSyncEngine.setReady(id);
    }
}