/*
* Copyright 2019 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.kotlin
import androidx.room.processor.Context
import kotlinx.metadata.jvm.KotlinClassHeader
import kotlinx.metadata.jvm.KotlinClassMetadata
import javax.lang.model.element.Element
import javax.lang.model.element.ExecutableElement
/**
* Utility class for processors that wants to run kotlin specific code.
*/
class KotlinMetadataElement(
val context: Context,
val element: Element,
private val classMetadata: KotlinClassMetadata.Class
) {
private val functionList: List<KmFunction> by lazy { classMetadata.readFunctions() }
private val constructorList: List<KmConstructor> by lazy { classMetadata.readConstructors() }
private val ExecutableElement.descriptor: String
get() = descriptor(context.processingEnv.typeUtils)
/**
* Returns the parameter names of the function or constructor if all have names embedded in the
* metadata.
*/
fun getParameterNames(method: ExecutableElement): List<String>? {
val methodSignature = method.descriptor
val paramList =
functionList.firstOrNull { it.descriptor == methodSignature }?.parameters
?: constructorList.firstOrNull { it.descriptor == methodSignature }?.parameters
return paramList?.map { it.name }
}
/**
* Finds the primary constructor descriptor of the class.
*/
fun findPrimaryConstructorSignature() = constructorList.first { it.isPrimary() }.descriptor
/**
* Checks if a method is a suspend function.
*/
fun isSuspendFunction(method: ExecutableElement) = functionList.firstOrNull {
it.descriptor == method.descriptor
}?.isSuspend() ?: false
companion object {
/**
* Creates a [KotlinMetadataElement] for the given element if it contains Kotlin metadata,
* otherwise this method returns null.
*
* Usually the [element] passed must represent a class. For example, if kotlin metadata is
* desired for a method, then the containing method should be used as parameter.
*/
fun createFor(context: Context, element: Element): KotlinMetadataElement? {
val metadata = getMetadataAnnotation(element)?.run {
KotlinClassHeader(
kind = kind,
metadataVersion = metadataVersion,
bytecodeVersion = bytecodeVersion,
data1 = data1,
data2 = data2,
extraString = extraString,
packageName = packageName,
extraInt = extraInt
).let {
// TODO: Support more metadata kind (file facade, synthetic class, etc...)
KotlinClassMetadata.read(it) as? KotlinClassMetadata.Class
}
}
return if (metadata != null) {
KotlinMetadataElement(context, element, metadata)
} else {
null
}
}
/**
* Search for Kotlin's Metadata annotation across the element's hierarchy.
*/
private fun getMetadataAnnotation(element: Element?): Metadata? =
if (element != null) {
element.getAnnotation(Metadata::class.java)
?: getMetadataAnnotation(element.enclosingElement)
} else {
null
}
}
}