src/com/android/launcher3/model/ModelWriter.java - LeafOS-Project/android_packages_apps_Launcher3 - Gitiles

 /*
  * Copyright (C) 2017 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.launcher3.model;

 import static com.android.launcher3.LauncherSettings.Favorites.TABLE_NAME;
 import static com.android.launcher3.provider.LauncherDbUtils.itemIdMatch;
 import static com.android.launcher3.util.Executors.MODEL_EXECUTOR;

 import android.content.ContentValues;
 import android.content.Context;
 import android.text.TextUtils;
 import android.util.Log;

 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;

 import com.android.launcher3.LauncherModel;
 import com.android.launcher3.LauncherModel.CallbackTask;
 import com.android.launcher3.LauncherSettings.Favorites;
 import com.android.launcher3.Utilities;
 import com.android.launcher3.celllayout.CellPosMapper;
 import com.android.launcher3.celllayout.CellPosMapper.CellPos;
 import com.android.launcher3.config.FeatureFlags;
 import com.android.launcher3.logging.FileLog;
 import com.android.launcher3.model.BgDataModel.Callbacks;
 import com.android.launcher3.model.data.FolderInfo;
 import com.android.launcher3.model.data.ItemInfo;
 import com.android.launcher3.model.data.LauncherAppWidgetInfo;
 import com.android.launcher3.model.data.WorkspaceItemInfo;
 import com.android.launcher3.provider.LauncherDbUtils.SQLiteTransaction;
 import com.android.launcher3.util.ContentWriter;
 import com.android.launcher3.util.Executors;
 import com.android.launcher3.util.ItemInfoMatcher;
 import com.android.launcher3.util.LooperExecutor;
 import com.android.launcher3.widget.LauncherWidgetHolder;

 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.List;
 import java.util.function.Predicate;
 import java.util.function.Supplier;
 import java.util.stream.Collectors;
 import java.util.stream.StreamSupport;

 /**
  * Class for handling model updates.
  */
 public class ModelWriter {

     private static final String TAG = "ModelWriter";

     private final Context mContext;
     private final LauncherModel mModel;
     private final BgDataModel mBgDataModel;
     private final LooperExecutor mUiExecutor;

     @Nullable
     private final Callbacks mOwner;

     private final boolean mVerifyChanges;

     // Keep track of delete operations that occur when an Undo option is present; we may not commit.
     private final List<ModelTask> mDeleteRunnables = new ArrayList<>();
     private boolean mPreparingToUndo;
     private final CellPosMapper mCellPosMapper;

     public ModelWriter(Context context, LauncherModel model, BgDataModel dataModel,
             boolean verifyChanges, CellPosMapper cellPosMapper, @Nullable Callbacks owner) {
         mContext = context;
         mModel = model;
         mBgDataModel = dataModel;
         mVerifyChanges = verifyChanges;
         mOwner = owner;
         mCellPosMapper = cellPosMapper;
         mUiExecutor = Executors.MAIN_EXECUTOR;
     }

     private void updateItemInfoProps(
             ItemInfo item, int container, int screenId, int cellX, int cellY) {
         CellPos modelPos = mCellPosMapper.mapPresenterToModel(cellX, cellY, screenId, container);

         item.container = container;
         item.cellX = modelPos.cellX;
         item.cellY = modelPos.cellY;
         item.screenId = modelPos.screenId;

     }

     /**
      * Adds an item to the DB if it was not created previously, or move it to a new
      * <container, screen, cellX, cellY>
      */
     public void addOrMoveItemInDatabase(ItemInfo item,
             int container, int screenId, int cellX, int cellY) {
         if (item.id == ItemInfo.NO_ID) {
             // From all apps
             addItemToDatabase(item, container, screenId, cellX, cellY);
         } else {
             // From somewhere else
             moveItemInDatabase(item, container, screenId, cellX, cellY);
         }
     }

     private void checkItemInfoLocked(int itemId, ItemInfo item, StackTraceElement[] stackTrace) {
         ItemInfo modelItem = mBgDataModel.itemsIdMap.get(itemId);
         if (modelItem != null && item != modelItem) {
             // check all the data is consistent
             if (!Utilities.IS_DEBUG_DEVICE && !FeatureFlags.IS_STUDIO_BUILD
                     && modelItem instanceof WorkspaceItemInfo
                     && item instanceof WorkspaceItemInfo) {
                 if (modelItem.title.toString().equals(item.title.toString()) &&
                         modelItem.getIntent().filterEquals(item.getIntent()) &&
                         modelItem.id == item.id &&
                         modelItem.itemType == item.itemType &&
                         modelItem.container == item.container &&
                         modelItem.screenId == item.screenId &&
                         modelItem.cellX == item.cellX &&
                         modelItem.cellY == item.cellY &&
                         modelItem.spanX == item.spanX &&
                         modelItem.spanY == item.spanY) {
                     // For all intents and purposes, this is the same object
                     return;
                 }
             }

             // the modelItem needs to match up perfectly with item if our model is
             // to be consistent with the database-- for now, just require
             // modelItem == item or the equality check above
             String msg = "item: " + ((item != null) ? item.toString() : "null") +
                     "modelItem: " +
                     ((modelItem != null) ? modelItem.toString() : "null") +
                     "Error: ItemInfo passed to checkItemInfo doesn't match original";
             RuntimeException e = new RuntimeException(msg);
             if (stackTrace != null) {
                 e.setStackTrace(stackTrace);
             }
             throw e;
         }
     }

     /**
      * Move an item in the DB to a new <container, screen, cellX, cellY>
      */
     public void moveItemInDatabase(final ItemInfo item,
             int container, int screenId, int cellX, int cellY) {
         updateItemInfoProps(item, container, screenId, cellX, cellY);
         notifyItemModified(item);

         enqueueDeleteRunnable(new UpdateItemRunnable(item, () ->
                 new ContentWriter(mContext)
                         .put(Favorites.CONTAINER, item.container)
                         .put(Favorites.CELLX, item.cellX)
                         .put(Favorites.CELLY, item.cellY)
                         .put(Favorites.RANK, item.rank)
                         .put(Favorites.SCREEN, item.screenId)));
     }

     /**
      * Move items in the DB to a new <container, screen, cellX, cellY>. We assume that the
      * cellX, cellY have already been updated on the ItemInfos.
      */
     public void moveItemsInDatabase(final ArrayList<ItemInfo> items, int container, int screen) {
         ArrayList<ContentValues> contentValues = new ArrayList<>();
         int count = items.size();
         notifyOtherCallbacks(c -> c.bindItemsModified(items));

         for (int i = 0; i < count; i++) {
             ItemInfo item = items.get(i);
             updateItemInfoProps(item, container, screen, item.cellX, item.cellY);

             final ContentValues values = new ContentValues();
             values.put(Favorites.CONTAINER, item.container);
             values.put(Favorites.CELLX, item.cellX);
             values.put(Favorites.CELLY, item.cellY);
             values.put(Favorites.RANK, item.rank);
             values.put(Favorites.SCREEN, item.screenId);

             contentValues.add(values);
         }
         enqueueDeleteRunnable(new UpdateItemsRunnable(items, contentValues));
     }

     /**
      * Move and/or resize item in the DB to a new <container, screen, cellX, cellY, spanX, spanY>
      */
     public void modifyItemInDatabase(final ItemInfo item,
             int container, int screenId, int cellX, int cellY, int spanX, int spanY) {
         updateItemInfoProps(item, container, screenId, cellX, cellY);
         item.spanX = spanX;
         item.spanY = spanY;
         notifyItemModified(item);
         new UpdateItemRunnable(item, () ->
                 new ContentWriter(mContext)
                         .put(Favorites.CONTAINER, item.container)
                         .put(Favorites.CELLX, item.cellX)
                         .put(Favorites.CELLY, item.cellY)
                         .put(Favorites.RANK, item.rank)
                         .put(Favorites.SPANX, item.spanX)
                         .put(Favorites.SPANY, item.spanY)
                         .put(Favorites.SCREEN, item.screenId))
                 .executeOnModelThread();
     }

     /**
      * Update an item to the database in a specified container.
      */
     public void updateItemInDatabase(ItemInfo item) {
         notifyItemModified(item);
         new UpdateItemRunnable(item, () -> {
             ContentWriter writer = new ContentWriter(mContext);
             item.onAddToDatabase(writer);
             return writer;
         }).executeOnModelThread();
     }

     private void notifyItemModified(ItemInfo item) {
         notifyOtherCallbacks(c -> c.bindItemsModified(Collections.singletonList(item)));
     }

     /**
      * Add an item to the database in a specified container. Sets the container, screen, cellX and
      * cellY fields of the item. Also assigns an ID to the item.
      */
     public void addItemToDatabase(final ItemInfo item,
             int container, int screenId, int cellX, int cellY) {
         updateItemInfoProps(item, container, screenId, cellX, cellY);

         item.id = mModel.getModelDbController().generateNewItemId();
         notifyOtherCallbacks(c -> c.bindItems(Collections.singletonList(item), false));

         ModelVerifier verifier = new ModelVerifier();
         final StackTraceElement[] stackTrace = new Throwable().getStackTrace();
         newModelTask(() -> {
             // Write the item on background thread, as some properties might have been updated in
             // the background.
             final ContentWriter writer = new ContentWriter(mContext);
             item.onAddToDatabase(writer);
             writer.put(Favorites._ID, item.id);

             mModel.getModelDbController().insert(Favorites.TABLE_NAME, writer.getValues(mContext));
             synchronized (mBgDataModel) {
                 checkItemInfoLocked(item.id, item, stackTrace);
                 mBgDataModel.addItem(mContext, item, true);
                 verifier.verifyModel();
             }
         }).executeOnModelThread();
     }

     /**
      * Removes the specified item from the database
      */
     public void deleteItemFromDatabase(ItemInfo item, @Nullable final String reason) {
         deleteItemsFromDatabase(Arrays.asList(item), reason);
     }

     /**
      * Removes all the items from the database matching {@param matcher}.
      */
     public void deleteItemsFromDatabase(@NonNull final Predicate<ItemInfo> matcher,
             @Nullable final String reason) {
         deleteItemsFromDatabase(StreamSupport.stream(mBgDataModel.itemsIdMap.spliterator(), false)
                         .filter(matcher).collect(Collectors.toList()), reason);
     }

     /**
      * Removes the specified items from the database
      */
     public void deleteItemsFromDatabase(final Collection<? extends ItemInfo> items,
             @Nullable final String reason) {
         ModelVerifier verifier = new ModelVerifier();
         FileLog.d(TAG, "removing items from db " + items.stream().map(
                 (item) -> item.getTargetComponent() == null ? ""
                         : item.getTargetComponent().getPackageName()).collect(
                 Collectors.joining(","))
                 + ". Reason: [" + (TextUtils.isEmpty(reason) ? "unknown" : reason) + "]");
         notifyDelete(items);
         enqueueDeleteRunnable(newModelTask(() -> {
             for (ItemInfo item : items) {
                 mModel.getModelDbController().delete(TABLE_NAME, itemIdMatch(item.id), null);
                 mBgDataModel.removeItem(mContext, item);
                 verifier.verifyModel();
             }
         }));
     }

     /**
      * Remove the specified folder and all its contents from the database.
      */
     public void deleteFolderAndContentsFromDatabase(final FolderInfo info) {
         ModelVerifier verifier = new ModelVerifier();
         notifyDelete(Collections.singleton(info));

         enqueueDeleteRunnable(newModelTask(() -> {
             mModel.getModelDbController().delete(Favorites.TABLE_NAME,
                     Favorites.CONTAINER + "=" + info.id, null);
             mBgDataModel.removeItem(mContext, info.contents);
             info.contents.clear();

             mModel.getModelDbController().delete(Favorites.TABLE_NAME,
                     Favorites._ID + "=" + info.id, null);
             mBgDataModel.removeItem(mContext, info);
             verifier.verifyModel();
         }));
     }

     /**
      * Deletes the widget info and the widget id.
      */
     public void deleteWidgetInfo(final LauncherAppWidgetInfo info, LauncherWidgetHolder holder,
             @Nullable final String reason) {
         notifyDelete(Collections.singleton(info));
         if (holder != null && !info.isCustomWidget() && info.isWidgetIdAllocated()) {
             // Deleting an app widget ID is a void call but writes to disk before returning
             // to the caller...
             enqueueDeleteRunnable(newModelTask(() -> holder.deleteAppWidgetId(info.appWidgetId)));
         }
         deleteItemFromDatabase(info, reason);
     }

     private void notifyDelete(Collection<? extends ItemInfo> items) {
         notifyOtherCallbacks(c -> c.bindWorkspaceComponentsRemoved(ItemInfoMatcher.ofItems(items)));
     }

     /**
      * Delete operations tracked using {@link #enqueueDeleteRunnable} will only be called
      * if {@link #commitDelete} is called. Note that one of {@link #commitDelete()} or
      * {@link #abortDelete} MUST be called after this method, or else all delete
      * operations will remain uncommitted indefinitely.
      */
     public void prepareToUndoDelete() {
         if (!mPreparingToUndo) {
             if (!mDeleteRunnables.isEmpty() && FeatureFlags.IS_STUDIO_BUILD) {
                 throw new IllegalStateException("There are still uncommitted delete operations!");
             }
             mDeleteRunnables.clear();
             mPreparingToUndo = true;
         }
     }

     /**
      * If {@link #prepareToUndoDelete} has been called, we store the Runnable to be run when
      * {@link #commitDelete()} is called (or abandoned if {@link #abortDelete} is called).
      * Otherwise, we run the Runnable immediately.
      */
     private void enqueueDeleteRunnable(ModelTask r) {
         if (mPreparingToUndo) {
             mDeleteRunnables.add(r);
         } else {
             r.executeOnModelThread();
         }
     }

     public void commitDelete() {
         mPreparingToUndo = false;
         mDeleteRunnables.forEach(ModelTask::executeOnModelThread);
         mDeleteRunnables.clear();
     }

     /**
      * Aborts a previous delete operation pending commit
      */
     public void abortDelete() {
         mPreparingToUndo = false;
         mDeleteRunnables.clear();
         // We do a full reload here instead of just a rebind because Folders change their internal
         // state when dragging an item out, which clobbers the rebind unless we load from the DB.
         mModel.forceReload();
     }

     private void notifyOtherCallbacks(CallbackTask task) {
         if (mOwner == null) {
             // If the call is happening from a model, it will take care of updating the callbacks
             return;
         }
         mUiExecutor.execute(() -> {
             for (Callbacks c : mModel.getCallbacks()) {
                 if (c != mOwner) {
                     task.execute(c);
                 }
             }
         });
     }

     private class UpdateItemRunnable extends UpdateItemBaseRunnable {
         private final ItemInfo mItem;
         private final Supplier<ContentWriter> mWriter;
         private final int mItemId;

         UpdateItemRunnable(ItemInfo item, Supplier<ContentWriter> writer) {
             mItem = item;
             mWriter = writer;
             mItemId = item.id;
         }

         @Override
         public void runImpl() {
             mModel.getModelDbController().update(
                     TABLE_NAME, mWriter.get().getValues(mContext), itemIdMatch(mItemId), null);
             updateItemArrays(mItem, mItemId);
         }
     }

     private class UpdateItemsRunnable extends UpdateItemBaseRunnable {
         private final ArrayList<ContentValues> mValues;
         private final ArrayList<ItemInfo> mItems;

         UpdateItemsRunnable(ArrayList<ItemInfo> items, ArrayList<ContentValues> values) {
             mValues = values;
             mItems = items;
         }

         @Override
         public void runImpl() {
             try (SQLiteTransaction t = mModel.getModelDbController().newTransaction()) {
                 int count = mItems.size();
                 for (int i = 0; i < count; i++) {
                     ItemInfo item = mItems.get(i);
                     final int itemId = item.id;
                     mModel.getModelDbController().update(
                             TABLE_NAME, mValues.get(i), itemIdMatch(itemId), null);
                     updateItemArrays(item, itemId);
                 }
                 t.commit();
             } catch (Exception e) {
                 e.printStackTrace();
             }
         }
     }

     private abstract class UpdateItemBaseRunnable extends ModelTask {
         private final StackTraceElement[] mStackTrace;
         private final ModelVerifier mVerifier = new ModelVerifier();

         UpdateItemBaseRunnable() {
             mStackTrace = new Throwable().getStackTrace();
         }

         protected void updateItemArrays(ItemInfo item, int itemId) {
             // Lock on mBgLock *after* the db operation
             synchronized (mBgDataModel) {
                 checkItemInfoLocked(itemId, item, mStackTrace);

                 if (item.container != Favorites.CONTAINER_DESKTOP &&
                         item.container != Favorites.CONTAINER_HOTSEAT) {
                     // Item is in a folder, make sure this folder exists
                     if (!mBgDataModel.folders.containsKey(item.container)) {
                         // An items container is being set to a that of an item which is not in
                         // the list of Folders.
                         String msg = "item: " + item + " container being set to: " +
                                 item.container + ", not in the list of folders";
                         Log.e(TAG, msg);
                     }
                 }

                 // Items are added/removed from the corresponding FolderInfo elsewhere, such
                 // as in Workspace.onDrop. Here, we just add/remove them from the list of items
                 // that are on the desktop, as appropriate
                 ItemInfo modelItem = mBgDataModel.itemsIdMap.get(itemId);
                 if (modelItem != null &&
                         (modelItem.container == Favorites.CONTAINER_DESKTOP ||
                                 modelItem.container == Favorites.CONTAINER_HOTSEAT)) {
                     switch (modelItem.itemType) {
                         case Favorites.ITEM_TYPE_APPLICATION:
                         case Favorites.ITEM_TYPE_DEEP_SHORTCUT:
                         case Favorites.ITEM_TYPE_FOLDER:
                         case Favorites.ITEM_TYPE_APP_PAIR:
                             if (!mBgDataModel.workspaceItems.contains(modelItem)) {
                                 mBgDataModel.workspaceItems.add(modelItem);
                             }
                             break;
                         default:
                             break;
                     }
                 } else {
                     mBgDataModel.workspaceItems.remove(modelItem);
                 }
                 mVerifier.verifyModel();
             }
         }
     }

     private abstract class ModelTask implements Runnable {

         private final int mLoadId = mBgDataModel.lastLoadId;

         @Override
         public final void run() {
             if (mLoadId != mModel.getLastLoadId()) {
                 Log.d(TAG, "Model changed before the task could execute");
                 return;
             }
             runImpl();
         }

         public final void executeOnModelThread() {
             MODEL_EXECUTOR.execute(this);
         }

         public abstract void runImpl();
     }

     private ModelTask newModelTask(Runnable r) {
         return new ModelTask() {
             @Override
             public void runImpl() {
                 r.run();
             }
         };
     }

     /**
      * Utility class to verify model updates are propagated properly to the callback.
      */
     public class ModelVerifier {

         final int startId;

         ModelVerifier() {
             startId = mBgDataModel.lastBindId;
         }

         void verifyModel() {
             if (!mVerifyChanges || !mModel.hasCallbacks()) {
                 return;
             }

             int executeId = mBgDataModel.lastBindId;

             mUiExecutor.post(() -> {
                 int currentId = mBgDataModel.lastBindId;
                 if (currentId > executeId) {
                     // Model was already bound after job was executed.
                     return;
                 }
                 if (executeId == startId) {
                     // Bound model has not changed during the job
                     return;
                 }

                 // Bound model was changed between submitting the job and executing the job
                 mModel.rebindCallbacks();
             });
         }
     }
 }
	/*
	* Copyright (C) 2017 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.launcher3.model;

	import static com.android.launcher3.LauncherSettings.Favorites.TABLE_NAME;
	import static com.android.launcher3.provider.LauncherDbUtils.itemIdMatch;
	import static com.android.launcher3.util.Executors.MODEL_EXECUTOR;

	import android.content.ContentValues;
	import android.content.Context;
	import android.text.TextUtils;
	import android.util.Log;

	import androidx.annotation.NonNull;
	import androidx.annotation.Nullable;

	import com.android.launcher3.LauncherModel;
	import com.android.launcher3.LauncherModel.CallbackTask;
	import com.android.launcher3.LauncherSettings.Favorites;
	import com.android.launcher3.Utilities;
	import com.android.launcher3.celllayout.CellPosMapper;
	import com.android.launcher3.celllayout.CellPosMapper.CellPos;
	import com.android.launcher3.config.FeatureFlags;
	import com.android.launcher3.logging.FileLog;
	import com.android.launcher3.model.BgDataModel.Callbacks;
	import com.android.launcher3.model.data.FolderInfo;
	import com.android.launcher3.model.data.ItemInfo;
	import com.android.launcher3.model.data.LauncherAppWidgetInfo;
	import com.android.launcher3.model.data.WorkspaceItemInfo;
	import com.android.launcher3.provider.LauncherDbUtils.SQLiteTransaction;
	import com.android.launcher3.util.ContentWriter;
	import com.android.launcher3.util.Executors;
	import com.android.launcher3.util.ItemInfoMatcher;
	import com.android.launcher3.util.LooperExecutor;
	import com.android.launcher3.widget.LauncherWidgetHolder;

	import java.util.ArrayList;
	import java.util.Arrays;
	import java.util.Collection;
	import java.util.Collections;
	import java.util.List;
	import java.util.function.Predicate;
	import java.util.function.Supplier;
	import java.util.stream.Collectors;
	import java.util.stream.StreamSupport;

	/**
	* Class for handling model updates.
	*/
	public class ModelWriter {

	private static final String TAG = "ModelWriter";

	private final Context mContext;
	private final LauncherModel mModel;
	private final BgDataModel mBgDataModel;
	private final LooperExecutor mUiExecutor;

	@Nullable
	private final Callbacks mOwner;

	private final boolean mVerifyChanges;

	// Keep track of delete operations that occur when an Undo option is present; we may not commit.
	private final List<ModelTask> mDeleteRunnables = new ArrayList<>();
	private boolean mPreparingToUndo;
	private final CellPosMapper mCellPosMapper;

	public ModelWriter(Context context, LauncherModel model, BgDataModel dataModel,
	boolean verifyChanges, CellPosMapper cellPosMapper, @Nullable Callbacks owner) {
	mContext = context;
	mModel = model;
	mBgDataModel = dataModel;
	mVerifyChanges = verifyChanges;
	mOwner = owner;
	mCellPosMapper = cellPosMapper;
	mUiExecutor = Executors.MAIN_EXECUTOR;
	}

	private void updateItemInfoProps(
	ItemInfo item, int container, int screenId, int cellX, int cellY) {
	CellPos modelPos = mCellPosMapper.mapPresenterToModel(cellX, cellY, screenId, container);

	item.container = container;
	item.cellX = modelPos.cellX;
	item.cellY = modelPos.cellY;
	item.screenId = modelPos.screenId;

	}

	/**
	* Adds an item to the DB if it was not created previously, or move it to a new
	* <container, screen, cellX, cellY>
	*/
	public void addOrMoveItemInDatabase(ItemInfo item,
	int container, int screenId, int cellX, int cellY) {
	if (item.id == ItemInfo.NO_ID) {
	// From all apps
	addItemToDatabase(item, container, screenId, cellX, cellY);
	} else {
	// From somewhere else
	moveItemInDatabase(item, container, screenId, cellX, cellY);
	}
	}

	private void checkItemInfoLocked(int itemId, ItemInfo item, StackTraceElement[] stackTrace) {
	ItemInfo modelItem = mBgDataModel.itemsIdMap.get(itemId);
	if (modelItem != null && item != modelItem) {
	// check all the data is consistent
	if (!Utilities.IS_DEBUG_DEVICE && !FeatureFlags.IS_STUDIO_BUILD
	&& modelItem instanceof WorkspaceItemInfo
	&& item instanceof WorkspaceItemInfo) {
	if (modelItem.title.toString().equals(item.title.toString()) &&
	modelItem.getIntent().filterEquals(item.getIntent()) &&
	modelItem.id == item.id &&
	modelItem.itemType == item.itemType &&
	modelItem.container == item.container &&
	modelItem.screenId == item.screenId &&
	modelItem.cellX == item.cellX &&
	modelItem.cellY == item.cellY &&
	modelItem.spanX == item.spanX &&
	modelItem.spanY == item.spanY) {
	// For all intents and purposes, this is the same object
	return;
	}
	}

	// the modelItem needs to match up perfectly with item if our model is
	// to be consistent with the database-- for now, just require
	// modelItem == item or the equality check above
	String msg = "item: " + ((item != null) ? item.toString() : "null") +
	"modelItem: " +
	((modelItem != null) ? modelItem.toString() : "null") +
	"Error: ItemInfo passed to checkItemInfo doesn't match original";
	RuntimeException e = new RuntimeException(msg);
	if (stackTrace != null) {
	e.setStackTrace(stackTrace);
	}
	throw e;
	}
	}

	/**
	* Move an item in the DB to a new <container, screen, cellX, cellY>
	*/
	public void moveItemInDatabase(final ItemInfo item,
	int container, int screenId, int cellX, int cellY) {
	updateItemInfoProps(item, container, screenId, cellX, cellY);
	notifyItemModified(item);

	enqueueDeleteRunnable(new UpdateItemRunnable(item, () ->
	new ContentWriter(mContext)
	.put(Favorites.CONTAINER, item.container)
	.put(Favorites.CELLX, item.cellX)
	.put(Favorites.CELLY, item.cellY)
	.put(Favorites.RANK, item.rank)
	.put(Favorites.SCREEN, item.screenId)));
	}

	/**
	* Move items in the DB to a new <container, screen, cellX, cellY>. We assume that the
	* cellX, cellY have already been updated on the ItemInfos.
	*/
	public void moveItemsInDatabase(final ArrayList<ItemInfo> items, int container, int screen) {
	ArrayList<ContentValues> contentValues = new ArrayList<>();
	int count = items.size();
	notifyOtherCallbacks(c -> c.bindItemsModified(items));

	for (int i = 0; i < count; i++) {
	ItemInfo item = items.get(i);
	updateItemInfoProps(item, container, screen, item.cellX, item.cellY);

	final ContentValues values = new ContentValues();
	values.put(Favorites.CONTAINER, item.container);
	values.put(Favorites.CELLX, item.cellX);
	values.put(Favorites.CELLY, item.cellY);
	values.put(Favorites.RANK, item.rank);
	values.put(Favorites.SCREEN, item.screenId);

	contentValues.add(values);
	}
	enqueueDeleteRunnable(new UpdateItemsRunnable(items, contentValues));
	}

	/**
	* Move and/or resize item in the DB to a new <container, screen, cellX, cellY, spanX, spanY>
	*/
	public void modifyItemInDatabase(final ItemInfo item,
	int container, int screenId, int cellX, int cellY, int spanX, int spanY) {
	updateItemInfoProps(item, container, screenId, cellX, cellY);
	item.spanX = spanX;
	item.spanY = spanY;
	notifyItemModified(item);
	new UpdateItemRunnable(item, () ->
	new ContentWriter(mContext)
	.put(Favorites.CONTAINER, item.container)
	.put(Favorites.CELLX, item.cellX)
	.put(Favorites.CELLY, item.cellY)
	.put(Favorites.RANK, item.rank)
	.put(Favorites.SPANX, item.spanX)
	.put(Favorites.SPANY, item.spanY)
	.put(Favorites.SCREEN, item.screenId))
	.executeOnModelThread();
	}

	/**
	* Update an item to the database in a specified container.
	*/
	public void updateItemInDatabase(ItemInfo item) {
	notifyItemModified(item);
	new UpdateItemRunnable(item, () -> {
	ContentWriter writer = new ContentWriter(mContext);
	item.onAddToDatabase(writer);
	return writer;
	}).executeOnModelThread();
	}

	private void notifyItemModified(ItemInfo item) {
	notifyOtherCallbacks(c -> c.bindItemsModified(Collections.singletonList(item)));
	}

	/**
	* Add an item to the database in a specified container. Sets the container, screen, cellX and
	* cellY fields of the item. Also assigns an ID to the item.
	*/
	public void addItemToDatabase(final ItemInfo item,
	int container, int screenId, int cellX, int cellY) {
	updateItemInfoProps(item, container, screenId, cellX, cellY);

	item.id = mModel.getModelDbController().generateNewItemId();
	notifyOtherCallbacks(c -> c.bindItems(Collections.singletonList(item), false));

	ModelVerifier verifier = new ModelVerifier();
	final StackTraceElement[] stackTrace = new Throwable().getStackTrace();
	newModelTask(() -> {
	// Write the item on background thread, as some properties might have been updated in
	// the background.
	final ContentWriter writer = new ContentWriter(mContext);
	item.onAddToDatabase(writer);
	writer.put(Favorites._ID, item.id);

	mModel.getModelDbController().insert(Favorites.TABLE_NAME, writer.getValues(mContext));
	synchronized (mBgDataModel) {
	checkItemInfoLocked(item.id, item, stackTrace);
	mBgDataModel.addItem(mContext, item, true);
	verifier.verifyModel();
	}
	}).executeOnModelThread();
	}

	/**
	* Removes the specified item from the database
	*/
	public void deleteItemFromDatabase(ItemInfo item, @Nullable final String reason) {
	deleteItemsFromDatabase(Arrays.asList(item), reason);
	}

	/**
	* Removes all the items from the database matching {@param matcher}.
	*/
	public void deleteItemsFromDatabase(@NonNull final Predicate<ItemInfo> matcher,
	@Nullable final String reason) {
	deleteItemsFromDatabase(StreamSupport.stream(mBgDataModel.itemsIdMap.spliterator(), false)
	.filter(matcher).collect(Collectors.toList()), reason);
	}

	/**
	* Removes the specified items from the database
	*/
	public void deleteItemsFromDatabase(final Collection<? extends ItemInfo> items,
	@Nullable final String reason) {
	ModelVerifier verifier = new ModelVerifier();
	FileLog.d(TAG, "removing items from db " + items.stream().map(
	(item) -> item.getTargetComponent() == null ? ""
	: item.getTargetComponent().getPackageName()).collect(
	Collectors.joining(","))
	+ ". Reason: [" + (TextUtils.isEmpty(reason) ? "unknown" : reason) + "]");
	notifyDelete(items);
	enqueueDeleteRunnable(newModelTask(() -> {
	for (ItemInfo item : items) {
	mModel.getModelDbController().delete(TABLE_NAME, itemIdMatch(item.id), null);
	mBgDataModel.removeItem(mContext, item);
	verifier.verifyModel();
	}
	}));
	}

	/**
	* Remove the specified folder and all its contents from the database.
	*/
	public void deleteFolderAndContentsFromDatabase(final FolderInfo info) {
	ModelVerifier verifier = new ModelVerifier();
	notifyDelete(Collections.singleton(info));

	enqueueDeleteRunnable(newModelTask(() -> {
	mModel.getModelDbController().delete(Favorites.TABLE_NAME,
	Favorites.CONTAINER + "=" + info.id, null);
	mBgDataModel.removeItem(mContext, info.contents);
	info.contents.clear();

	mModel.getModelDbController().delete(Favorites.TABLE_NAME,
	Favorites._ID + "=" + info.id, null);
	mBgDataModel.removeItem(mContext, info);
	verifier.verifyModel();
	}));
	}

	/**
	* Deletes the widget info and the widget id.
	*/
	public void deleteWidgetInfo(final LauncherAppWidgetInfo info, LauncherWidgetHolder holder,
	@Nullable final String reason) {
	notifyDelete(Collections.singleton(info));
	if (holder != null && !info.isCustomWidget() && info.isWidgetIdAllocated()) {
	// Deleting an app widget ID is a void call but writes to disk before returning
	// to the caller...
	enqueueDeleteRunnable(newModelTask(() -> holder.deleteAppWidgetId(info.appWidgetId)));
	}
	deleteItemFromDatabase(info, reason);
	}

	private void notifyDelete(Collection<? extends ItemInfo> items) {
	notifyOtherCallbacks(c -> c.bindWorkspaceComponentsRemoved(ItemInfoMatcher.ofItems(items)));
	}

	/**
	* Delete operations tracked using {@link #enqueueDeleteRunnable} will only be called
	* if {@link #commitDelete} is called. Note that one of {@link #commitDelete()} or
	* {@link #abortDelete} MUST be called after this method, or else all delete
	* operations will remain uncommitted indefinitely.
	*/
	public void prepareToUndoDelete() {
	if (!mPreparingToUndo) {
	if (!mDeleteRunnables.isEmpty() && FeatureFlags.IS_STUDIO_BUILD) {
	throw new IllegalStateException("There are still uncommitted delete operations!");
	}
	mDeleteRunnables.clear();
	mPreparingToUndo = true;
	}
	}

	/**
	* If {@link #prepareToUndoDelete} has been called, we store the Runnable to be run when
	* {@link #commitDelete()} is called (or abandoned if {@link #abortDelete} is called).
	* Otherwise, we run the Runnable immediately.
	*/
	private void enqueueDeleteRunnable(ModelTask r) {
	if (mPreparingToUndo) {
	mDeleteRunnables.add(r);
	} else {
	r.executeOnModelThread();
	}
	}

	public void commitDelete() {
	mPreparingToUndo = false;
	mDeleteRunnables.forEach(ModelTask::executeOnModelThread);
	mDeleteRunnables.clear();
	}

	/**
	* Aborts a previous delete operation pending commit
	*/
	public void abortDelete() {
	mPreparingToUndo = false;
	mDeleteRunnables.clear();
	// We do a full reload here instead of just a rebind because Folders change their internal
	// state when dragging an item out, which clobbers the rebind unless we load from the DB.
	mModel.forceReload();
	}

	private void notifyOtherCallbacks(CallbackTask task) {
	if (mOwner == null) {
	// If the call is happening from a model, it will take care of updating the callbacks
	return;
	}
	mUiExecutor.execute(() -> {
	for (Callbacks c : mModel.getCallbacks()) {
	if (c != mOwner) {
	task.execute(c);
	}
	}
	});
	}

	private class UpdateItemRunnable extends UpdateItemBaseRunnable {
	private final ItemInfo mItem;
	private final Supplier<ContentWriter> mWriter;
	private final int mItemId;

	UpdateItemRunnable(ItemInfo item, Supplier<ContentWriter> writer) {
	mItem = item;
	mWriter = writer;
	mItemId = item.id;
	}

	@Override
	public void runImpl() {
	mModel.getModelDbController().update(
	TABLE_NAME, mWriter.get().getValues(mContext), itemIdMatch(mItemId), null);
	updateItemArrays(mItem, mItemId);
	}
	}

	private class UpdateItemsRunnable extends UpdateItemBaseRunnable {
	private final ArrayList<ContentValues> mValues;
	private final ArrayList<ItemInfo> mItems;

	UpdateItemsRunnable(ArrayList<ItemInfo> items, ArrayList<ContentValues> values) {
	mValues = values;
	mItems = items;
	}

	@Override
	public void runImpl() {
	try (SQLiteTransaction t = mModel.getModelDbController().newTransaction()) {
	int count = mItems.size();
	for (int i = 0; i < count; i++) {
	ItemInfo item = mItems.get(i);
	final int itemId = item.id;
	mModel.getModelDbController().update(
	TABLE_NAME, mValues.get(i), itemIdMatch(itemId), null);
	updateItemArrays(item, itemId);
	}
	t.commit();
	} catch (Exception e) {
	e.printStackTrace();
	}
	}
	}

	private abstract class UpdateItemBaseRunnable extends ModelTask {
	private final StackTraceElement[] mStackTrace;
	private final ModelVerifier mVerifier = new ModelVerifier();

	UpdateItemBaseRunnable() {
	mStackTrace = new Throwable().getStackTrace();
	}

	protected void updateItemArrays(ItemInfo item, int itemId) {
	// Lock on mBgLock after the db operation
	synchronized (mBgDataModel) {
	checkItemInfoLocked(itemId, item, mStackTrace);

	if (item.container != Favorites.CONTAINER_DESKTOP &&
	item.container != Favorites.CONTAINER_HOTSEAT) {
	// Item is in a folder, make sure this folder exists
	if (!mBgDataModel.folders.containsKey(item.container)) {
	// An items container is being set to a that of an item which is not in
	// the list of Folders.
	String msg = "item: " + item + " container being set to: " +
	item.container + ", not in the list of folders";
	Log.e(TAG, msg);
	}
	}

	// Items are added/removed from the corresponding FolderInfo elsewhere, such
	// as in Workspace.onDrop. Here, we just add/remove them from the list of items
	// that are on the desktop, as appropriate
	ItemInfo modelItem = mBgDataModel.itemsIdMap.get(itemId);
	if (modelItem != null &&
	(modelItem.container == Favorites.CONTAINER_DESKTOP \|\|
	modelItem.container == Favorites.CONTAINER_HOTSEAT)) {
	switch (modelItem.itemType) {
	case Favorites.ITEM_TYPE_APPLICATION:
	case Favorites.ITEM_TYPE_DEEP_SHORTCUT:
	case Favorites.ITEM_TYPE_FOLDER:
	case Favorites.ITEM_TYPE_APP_PAIR:
	if (!mBgDataModel.workspaceItems.contains(modelItem)) {
	mBgDataModel.workspaceItems.add(modelItem);
	}
	break;
	default:
	break;
	}
	} else {
	mBgDataModel.workspaceItems.remove(modelItem);
	}
	mVerifier.verifyModel();
	}
	}
	}

	private abstract class ModelTask implements Runnable {

	private final int mLoadId = mBgDataModel.lastLoadId;

	@Override
	public final void run() {
	if (mLoadId != mModel.getLastLoadId()) {
	Log.d(TAG, "Model changed before the task could execute");
	return;
	}
	runImpl();
	}

	public final void executeOnModelThread() {
	MODEL_EXECUTOR.execute(this);
	}

	public abstract void runImpl();
	}

	private ModelTask newModelTask(Runnable r) {
	return new ModelTask() {
	@Override
	public void runImpl() {
	r.run();
	}
	};
	}

	/**
	* Utility class to verify model updates are propagated properly to the callback.
	*/
	public class ModelVerifier {

	final int startId;

	ModelVerifier() {
	startId = mBgDataModel.lastBindId;
	}

	void verifyModel() {
	if (!mVerifyChanges \|\| !mModel.hasCallbacks()) {
	return;
	}

	int executeId = mBgDataModel.lastBindId;

	mUiExecutor.post(() -> {
	int currentId = mBgDataModel.lastBindId;
	if (currentId > executeId) {
	// Model was already bound after job was executed.
	return;
	}
	if (executeId == startId) {
	// Bound model has not changed during the job
	return;
	}

	// Bound model was changed between submitting the job and executing the job
	mModel.rebindCallbacks();
	});
	}
	}
	}