Make FastServiceLoader compatible with Java 1.6

Author: qwwdfsad

kotlinx-coroutines-core/jvm/src/internal/FastServiceLoader.kt

@@ -52,18 +52,37 @@ internal object FastServiceLoader {
             val pathToJar = path.substringAfter("jar:file:").substringBefore('!')
             val entry = path.substringAfter("!/")
             // mind the verify = false flag!
-            (JarFile(pathToJar, false) as Closeable).use { file ->
-                BufferedReader(InputStreamReader((file as JarFile).getInputStream(ZipEntry(entry)), "UTF-8")).use { r ->
+            (JarFile(pathToJar, false)).use { file ->
+                BufferedReader(InputStreamReader(file.getInputStream(ZipEntry(entry)), "UTF-8")).use { r ->
                     return parseFile(r)
                 }
             }
         }
-        // Regular path for everything elese
+        // Regular path for everything else
         return BufferedReader(InputStreamReader(url.openStream())).use { reader ->
             parseFile(reader)
         }
     }
 
+    // JarFile does no implement Closesable on Java 1.6
+    private inline fun <R> JarFile.use(block: (JarFile) -> R): R {
+        var cause: Throwable? = null
+        try {
+            return block(this)
+        } catch (e: Throwable) {
+            cause = e
+            throw e
+        } finally {
+            try {
+                close()
+            } catch (closeException: Throwable) {
+                if (cause === null) throw closeException
+                cause.addSuppressed(closeException)
+                throw cause
+            }
+        }
+    }
+
     private fun parseFile(r: BufferedReader): List<String> {
         val names = mutableSetOf<String>()
         while (true) {