MultimapQueryResultAdapter.kt

/*
 * Copyright 2021 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.processing.XType
import androidx.room.ext.L
import androidx.room.ext.RoomTypeNames
import androidx.room.ext.S
import androidx.room.ext.T
import androidx.room.ext.W
import androidx.room.ext.implementsEqualsAndHashcode
import androidx.room.log.RLog
import androidx.room.processor.ProcessorErrors
import androidx.room.solver.types.CursorValueReader
import androidx.room.vo.MapInfo
import androidx.room.vo.Warning
import androidx.room.vo.columnNames
import com.squareup.javapoet.CodeBlock

/**
 * Common interface for Map and Multimap result adapters.
 */
interface MultimapQueryResultAdapter {
    val keyTypeArg: XType
    val valueTypeArg: XType

    companion object {
        /**
         * Checks if the @MapInfo annotation is needed for clarification regarding the return type
         * of a Dao method.
         */
        fun validateMapTypeArgs(
            keyTypeArg: XType,
            valueTypeArg: XType,
            keyReader: CursorValueReader?,
            valueReader: CursorValueReader?,
            mapInfo: MapInfo?,
            logger: RLog
        ) {

            if (!keyTypeArg.implementsEqualsAndHashcode()) {
                logger.w(
                    Warning.DOES_NOT_IMPLEMENT_EQUALS_HASHCODE,
                    ProcessorErrors.classMustImplementEqualsAndHashCode(
                        keyTypeArg.typeName.toString()
                    )
                )
            }

            val hasKeyColumnName = mapInfo?.keyColumnName?.isNotEmpty() ?: false
            if (!hasKeyColumnName && keyReader != null) {
                logger.e(
                    ProcessorErrors.keyMayNeedMapInfo(
                        keyTypeArg.typeName
                    )
                )
            }

            val hasValueColumnName = mapInfo?.valueColumnName?.isNotEmpty() ?: false
            if (!hasValueColumnName && valueReader != null) {
                logger.e(
                    ProcessorErrors.valueMayNeedMapInfo(
                        valueTypeArg.typeName
                    )
                )
            }
        }
    }

    /**
     * Iterates over all matched fields to check if all are null. If so, we continue in the while
     * loop to the next iteration.
     */
    fun getColumnNullCheck(cursorVarName: String, valueRowAdapter: RowAdapter): CodeBlock {
        return when (valueRowAdapter) {
            is PojoRowAdapter -> {
                val conditions = valueRowAdapter.fieldsWithIndices.map {
                    CodeBlock.of(
                        "$L.isNull($L)",
                        cursorVarName,
                        it.indexVar
                    )
                }
                CodeBlock.join(conditions, "$W&&$W")
            }
            is SingleNamedColumnRowAdapter -> {
                val condition = listOf(
                    CodeBlock.of(
                        "$L.isNull($L)",
                        cursorVarName,
                        valueRowAdapter.indexVarName
                    )
                )
                CodeBlock.join(condition, "")
            }
            is EntityRowAdapter -> {
                val condition = valueRowAdapter.entity.columnNames.map { columnName ->
                    CodeBlock.of(
                        "$L.isNull($T.getColumnIndex($L, $S))",
                        cursorVarName,
                        RoomTypeNames.CURSOR_UTIL,
                        cursorVarName,
                        columnName
                    )
                }
                CodeBlock.join(condition, "$W&&$W")
            }
            else -> {
                throw IllegalStateException("Unexpected value row adapter found: $valueRowAdapter")
            }
        }
    }
}