KspSyntheticContinuationParameterElement.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.synthetic
import androidx.room.compiler.processing.XAnnotated
import androidx.room.compiler.processing.XEquality
import androidx.room.compiler.processing.XExecutableParameterElement
import androidx.room.compiler.processing.XMemberContainer
import androidx.room.compiler.processing.XType
import androidx.room.compiler.processing.ksp.KSTypeVarianceResolverScope
import androidx.room.compiler.processing.ksp.KspAnnotated
import androidx.room.compiler.processing.ksp.KspAnnotated.UseSiteFilter.Companion.NO_USE_SITE
import androidx.room.compiler.processing.ksp.KspMethodElement
import androidx.room.compiler.processing.ksp.KspProcessingEnv
import androidx.room.compiler.processing.ksp.KspType
import androidx.room.compiler.processing.ksp.requireContinuationClass
import androidx.room.compiler.processing.ksp.returnTypeAsMemberOf
import androidx.room.compiler.processing.ksp.swapResolvedType
import com.google.devtools.ksp.symbol.Variance
/**
* XProcessing adds an additional argument to each suspend function for the continuation because
* this is what KAPT generates and Room needs it as long as it generates java code.
*/
internal class KspSyntheticContinuationParameterElement(
val env: KspProcessingEnv,
override val enclosingElement: KspMethodElement
) : XExecutableParameterElement,
XEquality,
XAnnotated by KspAnnotated.create(
env = env,
delegate = null, // does not matter, this is synthetic and has no annotations.
filter = NO_USE_SITE
) {
override fun isContinuationParam() = true
override fun isReceiverParam() = false
override fun isKotlinPropertyParam() = false
override fun isVarArgs() = false
override val name: String by lazy {
// KAPT uses `$completion` but it doesn't check for conflicts, we do. Be aware that before
// Kotlin 1.8.0 the param was named 'continuation'.
var candidate = PARAM_NAME
var suffix = 0
while (
enclosingElement.declaration.parameters.any { it.name?.asString() == candidate }
) {
candidate = PARAM_NAME + "_" + suffix
suffix ++
}
candidate
}
override val jvmName = name
override val equalityItems: Array<out Any?> by lazy {
arrayOf(PARAM_NAME, enclosingElement)
}
override val hasDefaultValue: Boolean
get() = false
override val type: KspType by lazy {
createAsMemberOf(closestMemberContainer.type)
}
override val fallbackLocationText: String
get() = "return type of ${enclosingElement.fallbackLocationText}"
// Not applicable
override val docComment: String? get() = null
override val closestMemberContainer: XMemberContainer by lazy {
enclosingElement.closestMemberContainer
}
override fun asMemberOf(other: XType): KspType {
return if (closestMemberContainer.type?.isSameType(other) != false) {
type
} else {
createAsMemberOf(other)
}
}
private fun createAsMemberOf(container: XType?): KspType {
check(container is KspType?)
val continuation = env.resolver.requireContinuationClass()
val asMember = enclosingElement.declaration.returnTypeAsMemberOf(
ksType = container?.ksType
)
val returnTypeRef = checkNotNull(enclosingElement.declaration.returnType) {
"cannot find return type reference for $this"
}
val returnTypeAsTypeArgument = env.resolver.getTypeArgument(
returnTypeRef.swapResolvedType(asMember),
// even though this will be CONTRAVARIANT when resolved to the JVM type, in Kotlin, it
// is still INVARIANT. (see [KSTypeVarianceResolver]
Variance.INVARIANT
)
val contType = continuation.asType(listOf(returnTypeAsTypeArgument))
return env.wrap(
ksType = contType,
allowPrimitives = false
).copyWithScope(
KSTypeVarianceResolverScope.MethodParameter(
kspExecutableElement = enclosingElement,
parameterIndex = enclosingElement.parameters.size - 1,
annotated = enclosingElement.declaration,
container = container?.ksType?.declaration,
asMemberOf = container
)
)
}
override fun kindName(): String {
return "synthetic continuation parameter"
}
override fun validate(): Boolean {
return true
}
override fun equals(other: Any?): Boolean {
return XEquality.equals(this, other)
}
override fun hashCode(): Int {
return XEquality.hashCode(equalityItems)
}
override fun toString(): String {
return name
}
companion object {
const val PARAM_NAME = "\$completion"
}
}