Add firrtl.options

This adds a new package, "firrtl.options", that provides a framework for
working with options inside and outside FIRRTL.

Small changes:
  - Make TerminateOnExit return the correct exit code
  - Deprecate mutable TerminateOnExit
  - Add immutable DoNotTermianteOnExit

Signed-off-by: Schuyler Eldridge <schuyler.eldridge@ibm.com>

1 files changed, 39 insertions, 0 deletions

diff --git a/src/main/scala/firrtl/options/OptionParser.scala b/src/main/scala/firrtl/options/OptionParser.scala
new file mode 100644
index 00000000..6d8095c0
--- /dev/null
+++ b/src/main/scala/firrtl/options/OptionParser.scala
@@ -0,0 +1,39 @@
+// See LICENSE for license details.
+
+package firrtl.options
+
+import firrtl.{FIRRTLException, AnnotationSeq}
+
+import scopt.OptionParser
+
+/** Causes an OptionParser to not call exit (call `sys.exit`) if the `--help` option is passed
+  */
+trait DoNotTerminateOnExit { this: OptionParser[_] =>
+  override def terminate(exitState: Either[String, Unit]): Unit = Unit
+}
+
+/** A modified OptionParser with mutable termination and additional checks
+  */
+trait DuplicateHandling extends OptionParser[AnnotationSeq] {
+
+  override def parse(args: Seq[String], init: AnnotationSeq): Option[AnnotationSeq] = {
+
+    /** Message for found duplicate options */
+    def msg(x: String, y: String) = s"""Duplicate $x "$y" (did your custom Transform or OptionsManager add this?)"""
+
+    val longDups = options.map(_.name).groupBy(identity).collect{ case (k, v) if v.size > 1 && k != "" => k }
+    val shortDups = options.map(_.shortOpt).flatten.groupBy(identity).collect{ case (k, v) if v.size > 1 => k }
+
+
+    if (longDups.nonEmpty)  {
+      throw new OptionsException(msg("long option", longDups.map("--" + _).mkString(",")), new IllegalArgumentException)
+    }
+
+    if (shortDups.nonEmpty) {
+      throw new OptionsException(msg("short option", shortDups.map("-" + _).mkString(",")), new IllegalArgumentException)
+    }
+
+    super.parse(args, init)
+  }
+
+}