ImmutableListQueryResultAdapter.kt

/*
 * Copyright 2020 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.XCodeBlock
import androidx.room.compiler.codegen.XCodeBlock.Builder.Companion.addLocalVal
import androidx.room.compiler.processing.XType
import androidx.room.ext.GuavaTypeNames
import androidx.room.solver.CodeGenScope

class ImmutableListQueryResultAdapter(
    private val typeArg: XType,
    private val rowAdapter: RowAdapter
) : QueryResultAdapter(listOf(rowAdapter)) {
    override fun convert(outVarName: String, cursorVarName: String, scope: CodeGenScope) {
        scope.builder.apply {
            rowAdapter.onCursorReady(cursorVarName = cursorVarName, scope = scope)
            val collectionType = GuavaTypeNames.IMMUTABLE_LIST.parametrizedBy(
                typeArg.asTypeName()
            )
            val immutableListBuilderType = GuavaTypeNames
                .IMMUTABLE_LIST_BUILDER.parametrizedBy(typeArg.asTypeName())
            val immutableListBuilderName = scope.getTmpVar("_immutableListBuilder")
            addLocalVariable(
                name = immutableListBuilderName,
                typeName = immutableListBuilderType,
                assignExpr = XCodeBlock.of(
                    language = language,
                    "%T.builder()",
                    GuavaTypeNames.IMMUTABLE_LIST
                )
            )

            val tmpVarName = scope.getTmpVar("_item")
            beginControlFlow("while (%L.moveToNext())", cursorVarName).apply {
                addLocalVariable(
                    name = tmpVarName,
                    typeName = typeArg.asTypeName()
                )
                rowAdapter.convert(tmpVarName, cursorVarName, scope)
                addStatement(
                    "%L.add(%L)",
                    immutableListBuilderName,
                    tmpVarName
                )
            }
            endControlFlow()
            addLocalVal(
                name = outVarName,
                typeName = collectionType,
                assignExprFormat = "%L.build()",
                immutableListBuilderName
            )
        }
    }
}