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/*
* 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 android.arch.persistence.room;
import android.arch.persistence.db.SimpleSQLiteQuery;
import android.arch.persistence.db.SupportSQLiteDatabase;
import android.arch.persistence.db.SupportSQLiteOpenHelper;
import android.arch.persistence.room.migration.Migration;
import android.database.Cursor;
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;
import android.support.annotation.RestrictTo;
import java.util.List;
/**
* An open helper that holds a reference to the configuration until the database is opened.
*
* @hide
*/
@SuppressWarnings("unused")
@RestrictTo(RestrictTo.Scope.LIBRARY_GROUP)
public class RoomOpenHelper extends SupportSQLiteOpenHelper.Callback {
@Nullable
private DatabaseConfiguration mConfiguration;
@NonNull
private final Delegate mDelegate;
@NonNull
private final String mIdentityHash;
public RoomOpenHelper(@NonNull DatabaseConfiguration configuration, @NonNull Delegate delegate,
@NonNull String identityHash) {
super(delegate.version);
mConfiguration = configuration;
mDelegate = delegate;
mIdentityHash = identityHash;
}
@Override
public void onConfigure(SupportSQLiteDatabase db) {
super.onConfigure(db);
}
@Override
public void onCreate(SupportSQLiteDatabase db) {
updateIdentity(db);
mDelegate.createAllTables(db);
mDelegate.onCreate(db);
}
@Override
public void onUpgrade(SupportSQLiteDatabase db, int oldVersion, int newVersion) {
boolean migrated = false;
if (mConfiguration != null) {
List<Migration> migrations = mConfiguration.migrationContainer.findMigrationPath(
oldVersion, newVersion);
if (migrations != null) {
for (Migration migration : migrations) {
migration.migrate(db);
}
mDelegate.validateMigration(db);
updateIdentity(db);
migrated = true;
}
}
if (!migrated) {
if (mConfiguration == null || mConfiguration.requireMigration) {
throw new IllegalStateException("A migration from " + oldVersion + " to "
+ newVersion + " is necessary. Please provide a Migration in the builder or call"
+ " fallbackToDestructiveMigration in the builder in which case Room will"
+ " re-create all of the tables.");
}
mDelegate.dropAllTables(db);
mDelegate.createAllTables(db);
}
}
@Override
public void onDowngrade(SupportSQLiteDatabase db, int oldVersion, int newVersion) {
onUpgrade(db, oldVersion, newVersion);
}
@Override
public void onOpen(SupportSQLiteDatabase db) {
super.onOpen(db);
checkIdentity(db);
mDelegate.onOpen(db);
// there might be too many configurations etc, just clear it.
mConfiguration = null;
}
private void checkIdentity(SupportSQLiteDatabase db) {
createMasterTableIfNotExists(db);
String identityHash = "";
Cursor cursor = db.query(new SimpleSQLiteQuery(RoomMasterTable.READ_QUERY));
//noinspection TryFinallyCanBeTryWithResources
try {
if (cursor.moveToFirst()) {
identityHash = cursor.getString(0);
}
} finally {
cursor.close();
}
if (!mIdentityHash.equals(identityHash)) {
throw new IllegalStateException("Room cannot verify the data integrity. Looks like"
+ " you've changed schema but forgot to update the version number. You can"
+ " simply fix this by increasing the version number.");
}
}
private void updateIdentity(SupportSQLiteDatabase db) {
createMasterTableIfNotExists(db);
db.execSQL(RoomMasterTable.createInsertQuery(mIdentityHash));
}
private void createMasterTableIfNotExists(SupportSQLiteDatabase db) {
db.execSQL(RoomMasterTable.CREATE_QUERY);
}
/**
* @hide
*/
@RestrictTo(RestrictTo.Scope.LIBRARY_GROUP)
public abstract static class Delegate {
public final int version;
public Delegate(int version) {
this.version = version;
}
protected abstract void dropAllTables(SupportSQLiteDatabase database);
protected abstract void createAllTables(SupportSQLiteDatabase database);
protected abstract void onOpen(SupportSQLiteDatabase database);
protected abstract void onCreate(SupportSQLiteDatabase database);
/**
* Called after a migration run to validate database integrity.
*
* @param db The SQLite database.
*/
protected abstract void validateMigration(SupportSQLiteDatabase db);
}
}
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