move StackTrace to util/log

LICENSE

@@ -1,4 +1,4 @@
-Copyright (c) 2008, 2009, 2010 Mark Harrah, Jason Zaugg
+Copyright (c) 2008, 2009, 2010 Mark Harrah, Tony Sloane, Jason Zaugg
 All rights reserved.
 
 Redistribution and use in source and binary forms, with or without

util/log/NOTICE

@@ -1,3 +1,3 @@
 Simple Build Tool: Logging Component
-Copyright 2008, 2009  Mark Harrah
+Copyright 2008, 2009, 2010  Mark Harrah, Tony Sloane
 Licensed under BSD-style license (see LICENSE)

util/log/StackTrace.scala

@@ -0,0 +1,63 @@
+/* sbt -- Simple Build Tool
+ * Copyright 2010 Tony Sloane
+ */
+package sbt
+
+object StackTrace
+{
+	def isSbtClass(name: String) = name.startsWith("sbt") || name.startsWith("xsbt")
+	/**
+		* Return a printable representation of the stack trace associated
+		* with t.  Information about t and its Throwable causes is included.
+		* The number of lines to be included for each Throwable is configured
+		* via d which should be greater than or equal to zero.  If d is zero,
+		* then all elements are included up to (but not including) the first
+		* element that comes from sbt. If d is greater than zero, then up to
+		* that many lines are included, where the line for the Throwable is
+		* counted plus one line for each stack element.  Less lines will be
+		* included if there are not enough stack elements.
+		*/
+	def trimmed(t : Throwable, d : Int) : String = {
+		require(d >= 0)
+		val b = new StringBuilder ()
+
+		def appendStackTrace (t : Throwable, first : Boolean) {
+
+			val include : StackTraceElement => Boolean =
+				if (d == 0)
+					element => !isSbtClass(element.getClassName)
+				else {
+					var count = d - 1
+					(_ => { count -= 1; count >= 0 })
+				}
+
+			def appendElement (e : StackTraceElement) {
+				b.append ("\tat ")
+				b.append (e)
+				b.append ('\n')
+			}
+
+			if (!first)
+				b.append ("Caused by: ")
+			b.append (t)
+			b.append ('\n')
+
+			val els = t.getStackTrace ()
+			var i = 0
+			while ((i < els.size) && include (els (i))) {
+				appendElement (els (i))
+				i += 1
+			}
+
+		}
+
+		appendStackTrace (t, true)
+		var c = t
+		while (c.getCause () != null) {
+			c = c.getCause ()
+			appendStackTrace (c, false)
+		}
+		b.toString ()
+
+	}
+}