Replay now enabled for presentation compiler.

1 files changed, 74 insertions, 0 deletions

diff --git a/src/compiler/scala/tools/nsc/io/Replay.scala b/src/compiler/scala/tools/nsc/io/Replay.scala
new file mode 100644
index 0000000000..5cb61b6cb1
--- /dev/null
+++ b/src/compiler/scala/tools/nsc/io/Replay.scala
@@ -0,0 +1,74 @@
+package scala.tools.nsc.io
+
+import java.io.{Reader, Writer}
+
+import Pickler._
+import Lexer.{Token, EOF}
+
+abstract class LogReplay {
+  def logreplay(event: String, x: => Boolean): Boolean
+  def logreplay[T: Pickler](event: String, x: => Option[T]): Option[T]
+  def close()
+  def flush()
+}
+
+class Logger(wr0: Writer) extends LogReplay {
+  val wr = new PrettyWriter(wr0)
+  private var first = true
+  private def insertComma() = if (first) first = false else wr.write(",")
+
+  def logreplay(event: String, x: => Boolean) = {
+    val xx = x
+    if (xx) { insertComma(); pkl[Unit].labelled(event).pickle(wr, ()) }
+    xx
+  }
+  def logreplay[T: Pickler](event: String, x: => Option[T]) = {
+    val xx = x
+    xx match {
+      case Some(y) => insertComma(); pkl[T].labelled(event).pickle(wr, y)
+      case None =>
+    }
+    xx
+  }
+  def close() { wr.close() }
+  def flush() { wr.flush() }
+}
+
+object NullLogger extends LogReplay {
+  def logreplay(event: String, x: => Boolean) = x
+  def logreplay[T: Pickler](event: String, x: => Option[T]) = x
+  def close() {}
+  def flush() {}
+}
+
+class Replayer(raw: Reader) extends LogReplay {
+  private val rd = new Lexer(raw)
+  private var nextComma = false
+
+  private def eatComma() =
+    if (nextComma) { rd.accept(','); nextComma = false }
+
+  def logreplay(event: String, x: => Boolean) =
+    if (rd.token == EOF) NullLogger.logreplay(event, x)
+    else {
+      eatComma()
+      pkl[Unit].labelled(event).unpickle(rd) match {
+        case UnpickleSuccess(_) => nextComma = true; true
+        case _ => false
+      }
+    }
+
+  def logreplay[T: Pickler](event: String, x: => Option[T]) =
+    if (rd.token == EOF) NullLogger.logreplay(event, x)
+    else {
+      eatComma()
+      pkl[T].labelled(event).unpickle(rd) match {
+        case UnpickleSuccess(y) => nextComma = true; Some(y)
+        case _ => None
+      }
+    }
+
+  def close() { raw.close() }
+  def flush() {}
+}
+