blob: 00268f287ccdb3367e2ac03f721af8aa686047c8 [file] [log] [blame]
/*
* Copyright 2021 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 androidx.room.processor
import androidx.room.AutoMigration
import androidx.room.compiler.processing.XTypeElement
import androidx.room.ext.RoomTypeNames
import androidx.room.migration.bundle.DatabaseBundle
import androidx.room.migration.bundle.SchemaBundle.deserialize
import androidx.room.util.DiffException
import androidx.room.util.SchemaDiffer
import androidx.room.vo.AutoMigrationResult
import java.io.File
class AutoMigrationProcessor(
val context: Context,
val element: XTypeElement,
val latestDbSchema: DatabaseBundle
) {
/**
* Retrieves two schemas of the same database provided in the @AutoMigration annotation,
* detects the schema changes that occurred between the two versions.
*
* @return the AutoMigrationResult containing the schema changes detected
*/
fun process(): AutoMigrationResult? {
if (!element.isInterface()) {
context.logger.e(
ProcessorErrors.AUTOMIGRATION_ANNOTATED_TYPE_ELEMENT_MUST_BE_INTERFACE,
element
)
return null
}
if (!context.processingEnv.requireType(RoomTypeNames.AUTO_MIGRATION_CALLBACK)
.isAssignableFrom(element.type)
) {
context.logger.e(
ProcessorErrors.AUTOMIGRATION_ELEMENT_MUST_IMPLEMENT_AUTOMIGRATION_CALLBACK,
element
)
return null
}
val annotationBox = element.toAnnotationBox(AutoMigration::class)
if (annotationBox == null) {
context.logger.e(
element,
ProcessorErrors.AUTOMIGRATION_ANNOTATION_MISSING
)
return null
}
val from = annotationBox.value.from
val to = annotationBox.value.to
if (to <= from) {
context.logger.e(
ProcessorErrors.autoMigrationToVersionMustBeGreaterThanFrom(to, from),
element
)
return null
}
val validatedFromSchemaFile = getValidatedSchemaFile(from) ?: return null
val fromSchemaBundle = validatedFromSchemaFile.inputStream().use {
deserialize(it).database
}
val validatedToSchemaFile = getValidatedSchemaFile(to) ?: return null
val toSchemaBundle = if (to == latestDbSchema.version) {
latestDbSchema
} else {
validatedToSchemaFile.inputStream().use {
deserialize(it).database
}
}
val schemaDiff = try {
SchemaDiffer(
fromSchemaBundle = fromSchemaBundle,
toSchemaBundle = toSchemaBundle
).diffSchemas()
} catch (ex: DiffException) {
context.logger.e(ex.errorMessage)
return null
}
return AutoMigrationResult(
element = element,
from = fromSchemaBundle.version,
to = toSchemaBundle.version,
addedColumns = schemaDiff.addedColumn,
addedTables = schemaDiff.addedTable
)
}
// TODO: File bug for not supporting downgrades.
// TODO: (b/180389433) If the files don't exist the getSchemaFile() method should return
// null and before calling process
private fun getValidatedSchemaFile(version: Int): File? {
val schemaFile = File(
context.schemaOutFolder,
"${element.className.enclosingClassName()}/$version.json"
)
if (!schemaFile.exists()) {
context.logger.e(
ProcessorErrors.autoMigrationSchemasNotFound(
context.schemaOutFolder.toString(),
"${element.className.enclosingClassName()}/$version.json"
),
element
)
return null
}
return schemaFile
}
}