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.binderprovider
18 
19 import androidx.room.ext.PagingTypeNames
20 import androidx.room.parser.ParsedQuery
21 import androidx.room.processor.Context
22 import androidx.room.processor.ProcessorErrors
23 import androidx.room.solver.QueryResultBinderProvider
24 import androidx.room.solver.query.result.DataSourceFactoryQueryResultBinder
25 import androidx.room.solver.query.result.ListQueryResultAdapter
26 import androidx.room.solver.query.result.PositionalDataSourceQueryResultBinder
27 import androidx.room.solver.query.result.QueryResultBinder
28 import javax.lang.model.type.DeclaredType
29 import javax.lang.model.type.TypeMirror
30 
31 class DataSourceFactoryQueryResultBinderProvider(val context: Context) : QueryResultBinderProvider {
<lambda>null32     private val dataSourceFactoryTypeMirror: TypeMirror? by lazy {
33         context.processingEnv.elementUtils
34                 .getTypeElement(PagingTypeNames.DATA_SOURCE_FACTORY.toString())?.asType()
35     }
36 
providenull37     override fun provide(declared: DeclaredType, query: ParsedQuery): QueryResultBinder {
38         if (query.tables.isEmpty()) {
39             context.logger.e(ProcessorErrors.OBSERVABLE_QUERY_NOTHING_TO_OBSERVE)
40         }
41         val typeArg = declared.typeArguments[1]
42         val adapter = context.typeAdapterStore.findRowAdapter(typeArg, query)?.let {
43             ListQueryResultAdapter(it)
44         }
45 
46         val tableNames = ((adapter?.accessedTableNames() ?: emptyList())
47                 + query.tables.map { it.name }).toSet()
48         val countedBinder = PositionalDataSourceQueryResultBinder(adapter, tableNames)
49         return DataSourceFactoryQueryResultBinder(countedBinder)
50     }
51 
matchesnull52     override fun matches(declared: DeclaredType): Boolean =
53             declared.typeArguments.size == 2 && isLivePagedList(declared)
54 
55     private fun isLivePagedList(declared: DeclaredType): Boolean {
56         if (dataSourceFactoryTypeMirror == null) {
57             return false
58         }
59         val erasure = context.processingEnv.typeUtils.erasure(declared)
60         // we don't want to return paged list unless explicitly requested
61         return context.processingEnv.typeUtils.isAssignable(dataSourceFactoryTypeMirror, erasure)
62     }
63 }
64