CoroutineTransactionMethodBinder.kt

/*
 * Copyright 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 androidx.room.solver.transaction.binder

import androidx.room.compiler.codegen.CodeLanguage
import androidx.room.compiler.codegen.XClassName
import androidx.room.compiler.codegen.XCodeBlock
import androidx.room.compiler.codegen.XMemberName.Companion.packageMember
import androidx.room.compiler.codegen.XPropertySpec
import androidx.room.compiler.codegen.XTypeName
import androidx.room.compiler.processing.XType
import androidx.room.ext.InvokeWithLambdaParameter
import androidx.room.ext.KotlinTypeNames
import androidx.room.ext.LambdaSpec
import androidx.room.ext.RoomTypeNames
import androidx.room.solver.CodeGenScope
import androidx.room.solver.transaction.result.TransactionMethodAdapter

/**
 * Binder that knows how to write suspending transaction wrapper methods.
 */
class CoroutineTransactionMethodBinder(
    private val returnType: XType,
    adapter: TransactionMethodAdapter,
    private val continuationParamName: String
) : TransactionMethodBinder(adapter) {
    override fun executeAndReturn(
        parameterNames: List<String>,
        daoName: XClassName,
        daoImplName: XClassName,
        dbProperty: XPropertySpec,
        scope: CodeGenScope
    ) {
        val innerContinuationParamName = scope.getTmpVar("_cont")
        val performBlock = InvokeWithLambdaParameter(
            scope = scope,
            functionName = RoomTypeNames.DB_UTIL.packageMember("performInTransactionSuspending"),
            argFormat = listOf("%N"),
            args = listOf(dbProperty),
            continuationParamName = continuationParamName,
            lambdaSpec = object : LambdaSpec(
                parameterTypeName = KotlinTypeNames.CONTINUATION.parametrizedBy(
                    XTypeName.getConsumerSuperName(returnType.asTypeName())
                ),
                parameterName = innerContinuationParamName,
                returnTypeName = KotlinTypeNames.ANY,
                javaLambdaSyntaxAvailable = scope.javaLambdaSyntaxAvailable
            ) {
                override fun XCodeBlock.Builder.body(scope: CodeGenScope) {
                    val adapterScope = scope.fork()
                    adapter.createDelegateToSuperCode(
                        parameterNames = when (scope.language) {
                            CodeLanguage.JAVA -> parameterNames + innerContinuationParamName
                            CodeLanguage.KOTLIN -> parameterNames
                        },
                        daoName = daoName,
                        daoImplName = daoImplName,
                        scope = adapterScope
                    )
                    val returnPrefix = when (scope.language) {
                        CodeLanguage.JAVA -> "return "
                        CodeLanguage.KOTLIN -> ""
                    }
                    addStatement("$returnPrefix%L", adapterScope.generate())
                }
            }
        )
        scope.builder.add("return %L", performBlock)
    }
}