room/compiler/src/main/kotlin/androidx/room/processor/Context.kt

/*
 * Copyright (C) 2016 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.processor

import androidx.room.RewriteQueriesToDropUnusedColumns
import androidx.room.log.RLog
import androidx.room.parser.expansion.ProjectionExpander
import androidx.room.parser.optimization.RemoveUnusedColumnQueryRewriter
import androidx.room.preconditions.Checks
import androidx.room.compiler.processing.XElement
import androidx.room.compiler.processing.XProcessingEnv
import androidx.room.compiler.processing.XType
import androidx.room.processor.cache.Cache
import androidx.room.solver.TypeAdapterStore
import androidx.room.verifier.DatabaseVerifier
import androidx.room.vo.Warning
import java.io.File
import java.util.LinkedHashSet

class Context private constructor(
    val processingEnv: XProcessingEnv,
    val logger: RLog,
    private val typeConverters: CustomConverterProcessor.ProcessResult,
    private val inheritedAdapterStore: TypeAdapterStore?,
    val cache: Cache,
    private val canRewriteQueriesToDropUnusedColumns: Boolean
) {
    val checker: Checks = Checks(logger)
    val COMMON_TYPES = CommonTypes(processingEnv)

    val typeAdapterStore by lazy {
        if (inheritedAdapterStore != null) {
            TypeAdapterStore.copy(this, inheritedAdapterStore)
        } else {
            TypeAdapterStore.create(this, typeConverters.converters)
        }
    }

    // set when database and its entities are processed.
    var databaseVerifier: DatabaseVerifier? = null
        private set

    val queryRewriter: QueryRewriter by lazy {
        val verifier = databaseVerifier
        if (verifier == null) {
            QueryRewriter.NoOpRewriter
        } else {
            if (canRewriteQueriesToDropUnusedColumns) {
                RemoveUnusedColumnQueryRewriter
            } else if (BooleanProcessorOptions.EXPAND_PROJECTION.getValue(processingEnv)) {
                ProjectionExpander(
                    tables = verifier.entitiesAndViews
                )
            } else {
                QueryRewriter.NoOpRewriter
            }
        }
    }

    companion object {
        val ARG_OPTIONS by lazy {
            ProcessorOptions.values().map { it.argName } +
                BooleanProcessorOptions.values().map { it.argName }
        }
    }

    fun attachDatabaseVerifier(databaseVerifier: DatabaseVerifier) {
        check(this.databaseVerifier == null) {
            "database verifier is already set"
        }
        this.databaseVerifier = databaseVerifier
    }

    constructor(processingEnv: XProcessingEnv) : this(
        processingEnv = processingEnv,
        logger = RLog(processingEnv.messager, emptySet(), null),
        typeConverters = CustomConverterProcessor.ProcessResult.EMPTY,
        inheritedAdapterStore = null,
        cache = Cache(null, LinkedHashSet(), emptySet()),
        canRewriteQueriesToDropUnusedColumns = false
    )

    class CommonTypes(val processingEnv: XProcessingEnv) {
        val VOID: XType by lazy {
            processingEnv.requireType("java.lang.Void")
        }
        val STRING: XType by lazy {
            processingEnv.requireType("java.lang.String")
        }
        val READONLY_COLLECTION: XType by lazy {
            if (processingEnv.backend == XProcessingEnv.Backend.KSP) {
                processingEnv.requireType("kotlin.collections.Collection")
            } else {
                processingEnv.requireType("java.util.Collection")
            }
        }
    }

    val schemaOutFolder by lazy {
        val arg = processingEnv.options[ProcessorOptions.OPTION_SCHEMA_FOLDER.argName]
        if (arg?.isNotEmpty() ?: false) {
            File(arg)
        } else {
            null
        }
    }

    fun <T> collectLogs(handler: (Context) -> T): Pair<T, RLog.CollectingMessager> {
        val collector = RLog.CollectingMessager()
        val subContext = Context(
            processingEnv = processingEnv,
            logger = RLog(collector, logger.suppressedWarnings, logger.defaultElement),
            typeConverters = this.typeConverters,
            inheritedAdapterStore = typeAdapterStore,
            cache = cache,
            canRewriteQueriesToDropUnusedColumns = canRewriteQueriesToDropUnusedColumns
        )
        subContext.databaseVerifier = databaseVerifier
        val result = handler(subContext)
        return Pair(result, collector)
    }

    fun fork(element: XElement, forceSuppressedWarnings: Set<Warning> = emptySet()): Context {
        val suppressedWarnings = SuppressWarningProcessor.getSuppressedWarnings(element)
        val processConvertersResult = CustomConverterProcessor.findConverters(this, element)
        val canReUseAdapterStore = processConvertersResult.classes.isEmpty()
        // order here is important since the sub context should give priority to new converters.
        val subTypeConverters = if (canReUseAdapterStore) {
            this.typeConverters
        } else {
            processConvertersResult + this.typeConverters
        }
        val subSuppressedWarnings =
            forceSuppressedWarnings + suppressedWarnings + logger.suppressedWarnings
        val subCache = Cache(cache, subTypeConverters.classes, subSuppressedWarnings)
        val subCanRemoveUnusedColumns = canRewriteQueriesToDropUnusedColumns ||
            element.hasRemoveUnusedColumnsAnnotation()
        val subContext = Context(
            processingEnv = processingEnv,
            logger = RLog(logger.messager, subSuppressedWarnings, element),
            typeConverters = subTypeConverters,
            inheritedAdapterStore = if (canReUseAdapterStore) typeAdapterStore else null,
            cache = subCache,
            canRewriteQueriesToDropUnusedColumns = subCanRemoveUnusedColumns
        )
        subContext.databaseVerifier = databaseVerifier
        return subContext
    }

    private fun XElement.hasRemoveUnusedColumnsAnnotation(): Boolean {
        return hasAnnotation(RewriteQueriesToDropUnusedColumns::class).also { annotated ->
            if (annotated && BooleanProcessorOptions.EXPAND_PROJECTION.getValue(processingEnv)) {
                logger.w(
                    warning = Warning.EXPAND_PROJECTION_WITH_REMOVE_UNUSED_COLUMNS,
                    element = this,
                    msg = ProcessorErrors.EXPAND_PROJECTION_ALONG_WITH_REMOVE_UNUSED
                )
            }
        }
    }

    enum class ProcessorOptions(val argName: String) {
        OPTION_SCHEMA_FOLDER("room.schemaLocation")
    }

    enum class BooleanProcessorOptions(val argName: String, private val defaultValue: Boolean) {
        INCREMENTAL("room.incremental", true),
        EXPAND_PROJECTION("room.expandProjection", false);

        /**
         * Returns the value of this option passed through the [XProcessingEnv]. If the value
         * is null or blank, it returns the default value instead.
         */
        fun getValue(processingEnv: XProcessingEnv): Boolean {
            val value = processingEnv.options[argName]
            return if (value.isNullOrBlank()) {
                defaultValue
            } else {
                value.toBoolean()
            }
        }
    }
}