JavaResourcesLoadingClassLoaderFactory.kt
/*
* Copyright 2022 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.privacysandbox.sdkruntime.client.loader
import androidx.privacysandbox.sdkruntime.client.config.LocalSdkConfig
import java.io.File
import java.io.IOException
import java.net.URL
import java.util.Enumeration
/**
* Delegate java resources related calls to app classloader.
*
* Classloaders normally delegate calls to parent classloader first, that's why this factory
* creates classloader that will work with java resources and pass it as parent to
* [codeClassLoaderFactory] thus overrides java resources for all classes loaded down the line.
*
* Add [LocalSdkConfig.javaResourcesRoot] as prefix to resource names before delegating calls,
* thus allowing isolating java resources for different local sdks.
*/
internal class JavaResourcesLoadingClassLoaderFactory(
private val appClassloader: ClassLoader,
private val codeClassLoaderFactory: SdkLoader.ClassLoaderFactory
) : SdkLoader.ClassLoaderFactory {
override fun createClassLoaderFor(
sdkConfig: LocalSdkConfig,
parent: ClassLoader
): ClassLoader {
val javaResourcesLoadingClassLoader = createJavaResourcesLoadingClassLoader(
sdkConfig,
parent
)
return codeClassLoaderFactory.createClassLoaderFor(
sdkConfig,
parent = javaResourcesLoadingClassLoader
)
}
private fun createJavaResourcesLoadingClassLoader(
sdkConfig: LocalSdkConfig,
parent: ClassLoader
): ClassLoader {
return if (sdkConfig.javaResourcesRoot == null) {
parent
} else {
JavaResourcesLoadingClassLoader(
parent,
appClassloader,
File(ASSETS_DIR, sdkConfig.javaResourcesRoot)
)
}
}
private class JavaResourcesLoadingClassLoader constructor(
parent: ClassLoader,
private val appClassloader: ClassLoader,
private val javaResourcePrefix: File
) : ClassLoader(parent) {
override fun findResource(name: String): URL? {
return appClassloader.getResource(File(javaResourcePrefix, name).path)
}
@Throws(IOException::class)
override fun findResources(name: String): Enumeration<URL> {
return appClassloader.getResources(File(javaResourcePrefix, name).path)
}
}
companion object {
const val ASSETS_DIR = "assets/"
}
}