Add support for Java 9+ (#182)

Add support for Java 9+
scalameta · Aug 19, 2019 · 364ebde · 364ebde
2 parents cba7690 + 264dddf
commit 364ebde
Showing 1 changed file with 44 additions and 4 deletions.
diff --git a/mdoc/src/main/scala/mdoc/internal/markdown/MarkdownCompiler.scala b/mdoc/src/main/scala/mdoc/internal/markdown/MarkdownCompiler.scala
@@ -15,6 +15,7 @@ import mdoc.internal.document.MdocNonFatal
 import mdoc.internal.pos.PositionSyntax
 import mdoc.internal.pos.PositionSyntax._
 import mdoc.internal.pos.TokenEditDistance
+import scala.collection.JavaConverters._
 import scala.meta._
 import scala.meta.inputs.Input
 import scala.meta.inputs.Position
@@ -25,6 +26,7 @@ import scala.tools.nsc.Global
 import scala.tools.nsc.Settings
 import scala.tools.nsc.io.AbstractFile
 import scala.tools.nsc.io.VirtualDirectory
+import sun.misc.Unsafe
 
 object MarkdownCompiler {
 
@@ -90,14 +92,52 @@ object MarkdownCompiler {
 
   private def defaultClasspath(fn: Path => Boolean): Classpath = {
     val paths =
-      getClass.getClassLoader
-        .asInstanceOf[URLClassLoader]
-        .getURLs
-        .iterator
+      getURLs(getClass.getClassLoader)
         .map(url => AbsolutePath(Paths.get(url.toURI)))
     Classpath(paths.toList)
   }
 
+  /**
+    * Utility to get SystemClassLoader/ClassLoader urls in java8 and java9+
+    *   Based upon: https://gist.github.com/hengyunabc/644f8e84908b7b405c532a51d8e34ba9
+    */
+  private def getURLs(classLoader: ClassLoader): Seq[URL] = {
+    if (classLoader.isInstanceOf[URLClassLoader]) {
+      classLoader.asInstanceOf[URLClassLoader].getURLs()
+      // java9+
+    } else if (classLoader
+        .getClass()
+        .getName()
+        .startsWith("jdk.internal.loader.ClassLoaders$")) {
+      try {
+        val field = classOf[Unsafe].getDeclaredField("theUnsafe")
+        field.setAccessible(true)
+        val unsafe = field.get(null).asInstanceOf[Unsafe]
+
+        // jdk.internal.loader.ClassLoaders.AppClassLoader.ucp
+        val ucpField = classLoader.getClass().getDeclaredField("ucp")
+        val ucpFieldOffset: Long = unsafe.objectFieldOffset(ucpField)
+        val ucpObject = unsafe.getObject(classLoader, ucpFieldOffset)
+
+        // jdk.internal.loader.URLClassPath.path
+        val pathField = ucpField.getType().getDeclaredField("path")
+        val pathFieldOffset = unsafe.objectFieldOffset(pathField)
+        val paths: Seq[URL] = unsafe
+          .getObject(ucpObject, pathFieldOffset)
+          .asInstanceOf[java.util.ArrayList[URL]]
+          .asScala
+
+        paths
+      } catch {
+        case ex: Exception =>
+          ex.printStackTrace()
+          Nil
+      }
+    } else {
+      Nil
+    }
+  }
+
 }
 
 class MarkdownCompiler(