InstantQueryResultBinder.kt

/*
 * 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 androidx.room.solver.query.result

import androidx.room.compiler.codegen.CodeLanguage
import androidx.room.compiler.codegen.XCodeBlock
import androidx.room.compiler.codegen.XCodeBlock.Builder.Companion.addLocalVal
import androidx.room.compiler.codegen.XMemberName.Companion.packageMember
import androidx.room.compiler.codegen.XPropertySpec
import androidx.room.compiler.codegen.XTypeName
import androidx.room.compiler.codegen.box
import androidx.room.ext.AndroidTypeNames
import androidx.room.ext.InvokeWithLambdaParameter
import androidx.room.ext.LambdaSpec
import androidx.room.ext.RoomTypeNames
import androidx.room.ext.SQLiteDriverTypeNames
import androidx.room.solver.CodeGenScope

/**
 * Instantly runs and returns the query.
 */
class InstantQueryResultBinder(adapter: QueryResultAdapter?) : QueryResultBinder(adapter) {
    override fun convertAndReturn(
        roomSQLiteQueryVar: String,
        canReleaseQuery: Boolean,
        dbProperty: XPropertySpec,
        inTransaction: Boolean,
        scope: CodeGenScope
    ) {
        scope.builder.apply {
            addStatement("%N.assertNotSuspendingTransaction()", dbProperty)
        }
        val transactionWrapper = if (inTransaction) {
            scope.builder.transactionWrapper(dbProperty.name)
        } else {
            null
        }
        transactionWrapper?.beginTransactionWithControlFlow()
        scope.builder.apply {
            val shouldCopyCursor = adapter?.shouldCopyCursor() == true
            val outVar = scope.getTmpVar("_result")
            val cursorVar = scope.getTmpVar("_cursor")
            addLocalVariable(
                name = cursorVar,
                typeName = AndroidTypeNames.CURSOR,
                assignExpr = XCodeBlock.of(
                    language,
                    "%M(%N, %L, %L, %L)",
                    RoomTypeNames.DB_UTIL.packageMember("query"),
                    dbProperty,
                    roomSQLiteQueryVar,
                    if (shouldCopyCursor) "true" else "false",
                    "null"
                )
            )
            beginControlFlow("try").apply {
                adapter?.convert(outVar, cursorVar, scope)
                transactionWrapper?.commitTransaction()
                addStatement("return %L", outVar)
            }
            nextControlFlow("finally").apply {
                addStatement("%L.close()", cursorVar)
                if (canReleaseQuery) {
                    addStatement("%L.release()", roomSQLiteQueryVar)
                }
            }
            endControlFlow()
        }
        transactionWrapper?.endTransactionWithControlFlow()
    }

    override fun isMigratedToDriver() = adapter?.isMigratedToDriver() == true

    override fun convertAndReturn(
        sqlQueryVar: String,
        dbProperty: XPropertySpec,
        bindStatement: CodeGenScope.(String) -> Unit,
        returnTypeName: XTypeName,
        inTransaction: Boolean,
        scope: CodeGenScope
    ) {
        val connectionVar = scope.getTmpVar("_connection")
        val performBlock = InvokeWithLambdaParameter(
            scope = scope,
            functionName = RoomTypeNames.DB_UTIL.packageMember("performBlocking"),
            argFormat = listOf("%N", "%L", "%L"),
            args = listOf(dbProperty, /* isReadOnly = */ true, inTransaction),
            lambdaSpec = object : LambdaSpec(
                parameterTypeName = SQLiteDriverTypeNames.CONNECTION,
                parameterName = connectionVar,
                returnTypeName = returnTypeName.box(),
                javaLambdaSyntaxAvailable = scope.javaLambdaSyntaxAvailable
            ) {
                override fun XCodeBlock.Builder.body(scope: CodeGenScope) {
                    val returnPrefix = when (language) {
                        CodeLanguage.JAVA -> "return "
                        CodeLanguage.KOTLIN -> ""
                    }
                    val statementVar = scope.getTmpVar("_stmt")
                    addLocalVal(
                        statementVar,
                        SQLiteDriverTypeNames.STATEMENT,
                        "%L.prepare(%L)",
                        connectionVar,
                        sqlQueryVar
                    )
                    beginControlFlow("try")
                    bindStatement(scope, statementVar)
                    val outVar = scope.getTmpVar("_result")
                    adapter?.convert(outVar, statementVar, scope)
                    addStatement("$returnPrefix%L", outVar)
                    nextControlFlow("finally")
                    addStatement("%L.close()", statementVar)
                    endControlFlow()
                }
            }
        )
        scope.builder.add("return %L", performBlock)
    }
}