1 /*
2  * Copyright (C) 2017 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.ext.AndroidTypeNames
20 import androidx.room.ext.L
21 import androidx.room.ext.N
22 import androidx.room.ext.T
23 import androidx.room.solver.CodeGenScope
24 import androidx.room.writer.DaoWriter
25 import com.squareup.javapoet.FieldSpec
26 import com.squareup.javapoet.MethodSpec
27 import javax.lang.model.element.Modifier
28 
29 /**
30  * Base class for query result binders that observe the database. It includes common functionality
31  * like creating a finalizer to release the query or creating the actual adapter call code.
32  */
33 abstract class BaseObservableQueryResultBinder(adapter: QueryResultAdapter?)
34     : QueryResultBinder(adapter) {
35 
createFinalizeMethodnull36     protected fun createFinalizeMethod(roomSQLiteQueryVar: String): MethodSpec {
37         return MethodSpec.methodBuilder("finalize").apply {
38             addModifiers(Modifier.PROTECTED)
39             addAnnotation(Override::class.java)
40             addStatement("$L.release()", roomSQLiteQueryVar)
41         }.build()
42     }
43 
createRunQueryAndReturnStatementsnull44     protected fun createRunQueryAndReturnStatements(builder: MethodSpec.Builder,
45                                                     roomSQLiteQueryVar: String,
46                                                     dbField: FieldSpec,
47                                                     inTransaction: Boolean,
48                                                     scope: CodeGenScope) {
49         val transactionWrapper = if (inTransaction) {
50             builder.transactionWrapper(dbField)
51         } else {
52             null
53         }
54         val outVar = scope.getTmpVar("_result")
55         val cursorVar = scope.getTmpVar("_cursor")
56         transactionWrapper?.beginTransactionWithControlFlow()
57         builder.apply {
58             addStatement("final $T $L = $N.query($L)", AndroidTypeNames.CURSOR, cursorVar,
59                     DaoWriter.dbField, roomSQLiteQueryVar)
60             beginControlFlow("try").apply {
61                 val adapterScope = scope.fork()
62                 adapter?.convert(outVar, cursorVar, adapterScope)
63                 addCode(adapterScope.builder().build())
64                 transactionWrapper?.commitTransaction()
65                 addStatement("return $L", outVar)
66             }
67             nextControlFlow("finally").apply {
68                 addStatement("$L.close()", cursorVar)
69             }
70             endControlFlow()
71         }
72         transactionWrapper?.endTransactionWithControlFlow()
73     }
74 }
75