InstantTransactionMethodBinder.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.box
import androidx.room.compiler.processing.XType
import androidx.room.compiler.processing.isKotlinUnit
import androidx.room.compiler.processing.isVoid
import androidx.room.ext.InvokeWithLambdaParameter
import androidx.room.ext.KotlinTypeNames
import androidx.room.ext.LambdaSpec
import androidx.room.ext.RoomTypeNames
import androidx.room.ext.SQLiteDriverTypeNames
import androidx.room.solver.CodeGenScope
import androidx.room.solver.transaction.result.TransactionMethodAdapter

/**
 * Binder that knows how to write instant (blocking) transaction wrapper methods.
 */
class InstantTransactionMethodBinder(
    private val returnType: XType,
    adapter: TransactionMethodAdapter,
) : TransactionMethodBinder(adapter) {
    override fun executeAndReturn(
        parameterNames: List<String>,
        daoName: XClassName,
        daoImplName: XClassName,
        dbProperty: XPropertySpec,
        scope: CodeGenScope
    ) {
        val returnPrefix = when (scope.language) {
            CodeLanguage.JAVA ->
                if (returnType.isVoid() || returnType.isKotlinUnit()) "" else "return "
            CodeLanguage.KOTLIN -> "return "
        }
        val performBlock = InvokeWithLambdaParameter(
            scope = scope,
            functionName = RoomTypeNames.DB_UTIL.packageMember("performBlocking"),
            argFormat = listOf("%N", "%L", "%L"),
            args = listOf(dbProperty, /* isReadOnly = */ false, /* inTransaction = */ true),
            lambdaSpec = object : LambdaSpec(
                parameterTypeName = SQLiteDriverTypeNames.CONNECTION,
                parameterName = when (scope.language) {
                    CodeLanguage.JAVA -> scope.getTmpVar("_connection")
                    CodeLanguage.KOTLIN -> "_"
                },
                returnTypeName = returnType.asTypeName().box(),
                javaLambdaSyntaxAvailable = scope.javaLambdaSyntaxAvailable
            ) {
                override fun XCodeBlock.Builder.body(scope: CodeGenScope) {
                    val adapterScope = scope.fork()
                    adapter.createDelegateToSuperCode(
                        parameterNames = parameterNames,
                        daoName = daoName,
                        daoImplName = daoImplName,
                        scope = adapterScope
                    )
                    when (scope.language) {
                        CodeLanguage.JAVA -> {
                            addStatement("$returnPrefix%L", adapterScope.generate())
                            if (returnPrefix.isEmpty()) {
                                addStatement("return %T.INSTANCE", KotlinTypeNames.UNIT)
                            }
                        }
                        CodeLanguage.KOTLIN -> {
                            addStatement("%L", adapterScope.generate())
                        }
                    }
                }
            }
        )
        scope.builder.add("$returnPrefix%L", performBlock)
    }
}