KspFieldElement.kt

/*
 * Copyright 2020 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.compiler.processing.ksp

import androidx.room.compiler.processing.XAnnotated
import androidx.room.compiler.processing.XFieldElement
import androidx.room.compiler.processing.XHasModifiers
import androidx.room.compiler.processing.XType
import androidx.room.compiler.processing.ksp.KspAnnotated.UseSiteFilter.Companion.NO_USE_SITE_OR_FIELD
import androidx.room.compiler.processing.ksp.synthetic.KspSyntheticPropertyMethodElement
import com.google.devtools.ksp.isPrivate
import com.google.devtools.ksp.symbol.KSPropertyDeclaration
import com.google.devtools.ksp.symbol.KSType
import com.google.devtools.ksp.symbol.Modifier

internal class KspFieldElement(
    env: KspProcessingEnv,
    override val declaration: KSPropertyDeclaration,
) : KspElement(env, declaration),
    XFieldElement,
    XHasModifiers by KspHasModifiers.create(declaration),
    XAnnotated by KspAnnotated.create(env, declaration, NO_USE_SITE_OR_FIELD) {

    override val enclosingElement: KspMemberContainer by lazy {
        declaration.requireEnclosingMemberContainer(env)
    }

    override val closestMemberContainer: KspMemberContainer by lazy {
        enclosingElement
    }

    override val name: String by lazy {
        declaration.simpleName.asString()
    }

    override val type: KspType by lazy {
        asMemberOf(enclosingElement.type?.ksType)
    }

    val syntheticAccessors: List<KspSyntheticPropertyMethodElement> by lazy {
        when {
            declaration.hasJvmFieldAnnotation() -> {
                // jvm fields cannot have accessors but KSP generates synthetic accessors for
                // them. We check for JVM field first before checking the getter
                emptyList()
            }
            declaration.isPrivate() -> emptyList()
            declaration.modifiers.contains(Modifier.CONST) -> {
                // No accessors are needed for const properties:
                // https://kotlinlang.org/docs/java-to-kotlin-interop.html#static-fields
                emptyList()
            }
            else -> {
                sequenceOf(declaration.getter, declaration.setter)
                    .filterNotNull()
                    .filterNot {
                        // KAPT does not generate methods for privates, KSP does so we filter
                        // them out.
                        it.modifiers.contains(Modifier.PRIVATE)
                    }
                    .map { accessor ->
                        KspSyntheticPropertyMethodElement.create(
                            env = env,
                            field = this,
                            accessor = accessor
                        )
                    }.toList()
            }
        }
    }

    val syntheticSetter
        get() = syntheticAccessors.firstOrNull {
            it.parameters.size == 1
        }

    override fun asMemberOf(other: XType): KspType {
        if (enclosingElement.type?.isSameType(other) != false) {
            return type
        }
        check(other is KspType)
        return asMemberOf(other.ksType)
    }

    private fun asMemberOf(ksType: KSType?): KspType {
        return env.wrap(
            originatingReference = declaration.type,
            ksType = declaration.typeAsMemberOf(ksType)
        )
    }

    companion object {
        fun create(env: KspProcessingEnv, declaration: KSPropertyDeclaration): KspFieldElement {
            return KspFieldElement(env, declaration)
        }
    }
}