The shutdown hook installed by jline has made life difficult for

sbt for a while.  This changes jline not to install it, and alters
the scala startup script to trap exit and re-enable echo on
recognizably unix platforms.  In addition it no longer installs
a shutdown hook to flush the repl history to disk, instead flushing
after every line.

Any bash reviewers out there? Unless someone raises a hand, no review.

git-svn-id: http://lampsvn.epfl.ch/svn-repos/scala/scala/trunk@23909 5e8d7ff9-d8ef-0310-90f0-a4852d11357a

src/compiler/scala/tools/ant/templates/tool-unix.tmpl

@@ -8,6 +8,26 @@
 # PARTICULAR PURPOSE.
 ##############################################################################
 
+function onExit() {
+  if [[ -n "$scaladebug" ]]; then
+    echo "scala script runner trapped exit, running handler."
+  fi
+    
+  local exit_status=${1:-$?}
+
+  # reenable echo
+  case "$TERM" in
+      rxvt* | xterm*)
+          stty icanon echo
+          ;;
+  esac
+  
+  exit $exit_status
+}
+
+# install exit handler
+trap onExit EXIT
+
 cygwin=false;
 case "`uname`" in
     CYGWIN*) cygwin=true ;;
@@ -50,9 +70,6 @@ if [ -z "$TOOL_CLASSPATH" ] ; then
     done
 fi
 
-EXEC=exec
-CYGWIN_TERM_PRE=
-CYGWIN_TERM_POST=
 CYGWIN_JLINE_TERMINAL=
 if $cygwin; then
     if [ "$OS" = "Windows_NT" ] && cygpath -m .>/dev/null 2>/dev/null ; then
@@ -64,15 +81,10 @@ if $cygwin; then
     TOOL_CLASSPATH=`cygpath --path --$format "$TOOL_CLASSPATH"`
     case "$TERM" in
         rxvt* | xterm*)
-            EXEC=
-            CYGWIN_TERM_PRE="stty -icanon min 1 -echo"
-            CYGWIN_TERM_POST="stty icanon echo"
+            stty -icanon min 1 -echo
             CYGWIN_JLINE_TERMINAL="-Djline.terminal=jline.UnixTerminal"
-            trap "$CYGWIN_TERM_POST" SIGINT
         ;;
     esac
-else
-    trap "stty echo" SIGINT
 fi
 
 [ -n "$JAVA_OPTS" ] || JAVA_OPTS="@javaflags@"
@@ -117,9 +129,7 @@ if [ -z "$JAVACMD" -a -n "$JAVA_HOME" -a -x "$JAVA_HOME/bin/java" ]; then
     JAVACMD="$JAVA_HOME/bin/java"
 fi
 
-eval $CYGWIN_TERM_PRE
-
-$EXEC "${JAVACMD:=java}" \
+"${JAVACMD:=java}" \
   $JAVA_OPTS \
   "${java_args[@@]}" \
   $CPSWITCH \
@@ -128,5 +138,3 @@ $EXEC "${JAVACMD:=java}" \
   -Denv.emacs="$EMACS" \
   $CYGWIN_JLINE_TERMINAL \
   @properties@ @class@ @toolflags@ "$@@"
-  
-eval $CYGWIN_TERM_POST

src/compiler/scala/tools/nsc/interpreter/History.scala

@@ -34,7 +34,14 @@ object History {
   val ScalaHistoryFile = ".scala_history"
   
   def apply(): History = new History(
-    try new FileHistory(new File(userHome, ScalaHistoryFile))
+    try new FileHistory(new File(userHome, ScalaHistoryFile)) {
+      // flush after every add to avoid installing a shutdown hook.
+      // (The shutdown hook approach also loses history when they aren't run.)
+      override def add(item: CharSequence): Unit = {
+        super.add(item)
+        flush()
+      }
+    }
     catch { 
       case x: Exception => 
         Console.println("Error creating file history: memory history only. " + x)

src/compiler/scala/tools/nsc/interpreter/JLineReader.scala

@@ -9,20 +9,12 @@ package interpreter
 import java.io.File
 import jline.console.ConsoleReader
 import jline.console.completer._
-import jline.console.history.{ History => JHistory }
 
 /** Reads from the console using JLine */
 class JLineReader(interpreter: Interpreter) extends InteractiveReader {
   def this() = this(null)
   
-  override lazy val history    = {
-    val h = History()
-    system addShutdownHook {
-      repldbg("Flushing history")
-      h.flush()
-    }
-    Some(h)
-  }
+  override lazy val history    = Some(History())
   override lazy val completion = Option(interpreter) map (x => new Completion(x))
   override def reset()         = consoleReader.getTerminal().reset()
   override def init()          = consoleReader.getTerminal().init()

src/jline/src/main/java/jline/TerminalSupport.java

@@ -8,6 +8,7 @@
 package jline;
 
 import jline.internal.Log;
+import jline.internal.Configuration;
 
 import java.io.IOException;
 import java.io.InputStream;
@@ -24,11 +25,15 @@ public abstract class TerminalSupport
 {
     public static String DEFAULT_KEYBINDINGS_PROPERTIES = "keybindings.properties";
 
+    public static final String JLINE_SHUTDOWNHOOK = "jline.shutdownhook";
+
     public static final int DEFAULT_WIDTH = 80;
 
     public static final int DEFAULT_HEIGHT = 24;
 
     private Thread shutdownHook;
+    
+    private boolean shutdownHookEnabled;
 
     private boolean supported;
 
@@ -38,6 +43,7 @@ public abstract class TerminalSupport
 
     protected TerminalSupport(final boolean supported) {
         this.supported = supported;
+        this.shutdownHookEnabled = Configuration.getBoolean(JLINE_SHUTDOWNHOOK, false);
     }
 
     public void init() throws Exception {
@@ -54,7 +60,14 @@ public abstract class TerminalSupport
         init();
     }
 
+    // Shutdown hooks causes classloader leakage in sbt,
+    // so they are only installed if -Djline.shutdownhook is true.
     protected void installShutdownHook(final Thread hook) {
+        if (!shutdownHookEnabled) {
+            Log.debug("Not install shutdown hook " + hook + " because they are disabled.");
+            return;
+        }
+            
         assert hook != null;
 
         if (shutdownHook != null) {
@@ -72,6 +85,9 @@ public abstract class TerminalSupport
     }
 
     protected void removeShutdownHook() {
+        if (!shutdownHookEnabled)
+            return;
+      
         if (shutdownHook != null) {
             try {
                 Runtime.getRuntime().removeShutdownHook(shutdownHook);