1 files changed, 62 insertions, 0 deletions
diff --git a/plugin/src/main/scala/ch/jodersky/sbt/jni/util/BytecodeUtil.scala b/plugin/src/main/scala/ch/jodersky/sbt/jni/util/BytecodeUtil.scala
new file mode 100644
index 0000000..fe728a6
--- /dev/null
+++ b/plugin/src/main/scala/ch/jodersky/sbt/jni/util/BytecodeUtil.scala
@@ -0,0 +1,62 @@
+package ch.jodersky.sbt.jni
+package util
+
+import java.io.{ File, FileInputStream, Closeable }
+import scala.collection.mutable.{ HashSet }
+
+import org.objectweb.asm.{ ClassReader, ClassVisitor, MethodVisitor, Opcodes }
+
+object BytecodeUtil {
+
+  private class NativeFinder extends ClassVisitor(Opcodes.ASM5) {
+
+    // classes found to contain at least one @native def
+    val _nativeClasses = new HashSet[String]
+    def nativeClasses = _nativeClasses.toSet
+
+    private var fullyQualifiedName: String = ""
+
+    override def visit(version: Int, access: Int, name: String, signature: String,
+      superName: String, interfaces: Array[String]): Unit = {
+      fullyQualifiedName = name.replaceAll("/", ".")
+    }
+
+    override def visitMethod(access: Int, name: String, desc: String,
+      signature: String, exceptions: Array[String]): MethodVisitor = {
+
+      val isNative = (access & Opcodes.ACC_NATIVE) != 0
+
+      if (isNative) {
+        _nativeClasses += fullyQualifiedName
+      }
+
+      null //return null, do not visit method further
+    }
+
+  }
+
+  private def using[A >: Null <: Closeable, R](mkStream: => A)(action: A => R): R = {
+    var stream: A = null
+    try {
+      stream = mkStream
+      action(stream)
+    } finally {
+      if (stream != null) {
+        stream.close()
+      }
+    }
+  }
+
+  /** Finds classes containing native implementations.
+    * @param classFile java class file from which classes are read
+    * @return all fully qualified names of classes that contain at least one member annotated
+    * with @native
+    */
+  def nativeClasses(classFile: File): Set[String] = using(new FileInputStream(classFile)) { in =>
+    val reader = new ClassReader(in)
+    val finder = new NativeFinder
+    reader.accept(finder, 0)
+    finder.nativeClasses
+  }
+
+}