Introduce DynamicClassLoader

app/src/main/java/com/topjohnwu/magisk/utils/DynamicClassLoader.kt

@@ -0,0 +1,61 @@
+package com.topjohnwu.magisk.utils
+
+import dalvik.system.DexClassLoader
+import java.io.File
+import java.io.IOException
+import java.net.URL
+import java.util.*
+
+@Suppress("FunctionName")
+inline fun <reified T> T.DynamicClassLoader(apk: File) = DynamicClassLoader(apk, T::class.java.classLoader)
+
+class DynamicClassLoader(apk: File, parent: ClassLoader?)
+    : DexClassLoader(apk.path, apk.parent, null, parent) {
+
+    private val base by lazy { Any::class.java.classLoader!! }
+
+    @Throws(ClassNotFoundException::class)
+    override fun loadClass(name: String, resolve: Boolean) : Class<*>
+        = findLoadedClass(name) ?: runCatching {
+            base.loadClass(name)
+        }.getOrElse {
+            runCatching {
+                findClass(name)
+            }.getOrElse { err ->
+                runCatching {
+                    parent.loadClass(name)
+                }.getOrElse { throw err }
+            }
+        }
+
+    override fun getResource(name: String) = base.getResource(name)
+            ?: findResource(name)
+            ?: parent?.getResource(name)
+
+    @Throws(IOException::class)
+    override fun getResources(name: String): Enumeration<URL> {
+        val resources = mutableListOf(
+                base.getResources(name),
+                findResources(name), parent.getResources(name))
+        return object : Enumeration<URL> {
+            override fun hasMoreElements(): Boolean {
+                while (true) {
+                    if (resources.isEmpty())
+                        return false
+                    if (!resources[0].hasMoreElements()) {
+                        resources.removeAt(0)
+                    } else {
+                        return true
+                    }
+                }
+            }
+
+            override fun nextElement(): URL {
+                if (!hasMoreElements())
+                    throw NoSuchElementException()
+                return resources[0].nextElement()
+            }
+        }
+    }
+
+}