1 /*
<lambda>null2  * Copyright (C) 2016 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 package androidx.room.solver.query.result
18 
19 import androidx.room.compiler.codegen.CodeLanguage
20 import androidx.room.compiler.codegen.XCodeBlock.Builder.Companion.applyTo
21 import androidx.room.compiler.processing.XNullability
22 import androidx.room.solver.CodeGenScope
23 
24 /** Wraps a row adapter when there is only 1 item in the result */
25 class SingleItemQueryResultAdapter(private val rowAdapter: RowAdapter) :
26     QueryResultAdapter(listOf(rowAdapter)) {
27     val type = rowAdapter.out
28 
29     override fun convert(outVarName: String, stmtVarName: String, scope: CodeGenScope) {
30         scope.builder.apply {
31             rowAdapter.onStatementReady(stmtVarName = stmtVarName, scope = scope)
32             addLocalVariable(outVarName, type.asTypeName())
33             beginControlFlow("if (%L.step())", stmtVarName).apply {
34                 rowAdapter.convert(outVarName, stmtVarName, scope)
35             }
36             nextControlFlow("else").applyTo { language ->
37                 val defaultValue = rowAdapter.out.defaultValue()
38                 if (
39                     language == CodeLanguage.KOTLIN &&
40                         type.nullability == XNullability.NONNULL &&
41                         defaultValue == "null"
42                 ) {
43                     addStatement(
44                         "error(%S)",
45                         "The query result was empty, but expected a single row to " +
46                             "return a NON-NULL object of " +
47                             "type <${type.asTypeName().toString(language)}>."
48                     )
49                 } else {
50                     addStatement("%L = %L", outVarName, rowAdapter.out.defaultValue())
51                 }
52             }
53             endControlFlow()
54         }
55     }
56 }
57