From 890a7c509552fe97f8df00833c3d57d556ca6337 Mon Sep 17 00:00:00 2001
From: Burak Emir <emir@epfl.ch>
Date: Sat, 12 Apr 2008 01:58:00 +0000
Subject: made xml.pull functional

---
 src/library/scala/xml/pull/XMLEvent.scala       | 20 ++++++++++++--
 src/library/scala/xml/pull/XMLEventReader.scala | 35 +++++++++++++++++--------
 test/files/jvm/xmlpull.scala                    | 31 ++++++++++++++++++++++
 3 files changed, 73 insertions(+), 13 deletions(-)
 create mode 100644 test/files/jvm/xmlpull.scala

diff --git a/src/library/scala/xml/pull/XMLEvent.scala b/src/library/scala/xml/pull/XMLEvent.scala
index 622a3e7b87..65b8503eed 100644
--- a/src/library/scala/xml/pull/XMLEvent.scala
+++ b/src/library/scala/xml/pull/XMLEvent.scala
@@ -12,9 +12,25 @@
 package scala.xml.pull
 
 /** This class represents an XML event for pull parsing.
+ *  Pull parsing means that during the traversal of the XML
+ *  tree we are parsing, each "event" is returned to the caller
+ *  and the traversal is suspended.
  */
 trait XMLEvent
 
-case class ElemStart(pre: String, label: String, attrs: MetaData, scope: NamespaceBinding) extends XMLEvent
+/** An element is encountered the first time */
+case class EvElemStart(pre: String, label: String, attrs: MetaData, scope: NamespaceBinding) extends XMLEvent
 
-case class ElemEnd(pre: String, label: String) extends XMLEvent
+/** An element is encountered the last time */
+case class EvElemEnd(pre: String, label: String) extends XMLEvent
+/** A text node is encountered */
+case class EvText(text: String) extends XMLEvent
+
+/** An entity reference is encountered */
+case class EvEntityRef(entity: String) extends XMLEvent
+
+/** A processing instruction is encountered */
+case class EvProcInstr(target: String, text: String) extends XMLEvent
+
+/** A comment is encountered */
+case class EvComment(text: String) extends XMLEvent
diff --git a/src/library/scala/xml/pull/XMLEventReader.scala b/src/library/scala/xml/pull/XMLEventReader.scala
index bcc48af1e7..e17a9e0017 100644
--- a/src/library/scala/xml/pull/XMLEventReader.scala
+++ b/src/library/scala/xml/pull/XMLEventReader.scala
@@ -58,7 +58,7 @@ class XMLEventReader extends Iterator[XMLEvent] {
       wait()
     }
     continue = true
-    notifyAll
+    notify()
   }
   def getAndClearEvent: XMLEvent = synchronized {
     while (xmlEvent eq null) {
@@ -72,10 +72,14 @@ class XMLEventReader extends Iterator[XMLEvent] {
     xmlEvent = e
   }
 
-  def doNotify() = synchronized {
+  def doNotify(): NodeSeq = synchronized {
     XMLEventReader.this.continue = false
-    notifyAll()
-    while (!XMLEventReader.this.continue) wait();
+    notify()
+    while (!XMLEventReader.this.continue) {
+      try { wait() } catch {
+       case _: java.lang.InterruptedException => /* ignore */
+	  }
+	}
     NodeSeq.Empty
   }
 
@@ -89,38 +93,47 @@ class XMLEventReader extends Iterator[XMLEvent] {
 
   def hasNext = true
 
+  // After calling stop, one must call initialize to be able to get new events.
+  def stop = {
+    continue = true;
+    parserThread.interrupt();
+    parserThread = null;
+  }
+
   var parserThread: Thread = null
 
   class Parser extends MarkupHandler with MarkupParser with ExternalSources with Runnable {
 
     val preserveWS = true
     val input = XMLEventReader.this.getSource
+	// document must contain one element - avoid spurious syntax error
+    final val ignore_node = <ignore/>
 
     override def elemStart(pos: Int, pre: String, label: String, attrs: MetaData, scope: NamespaceBinding) {
-      setEvent(ElemStart(pre, label, attrs, scope)); doNotify
+      setEvent(EvElemStart(pre, label, attrs, scope)); doNotify
     }
 
     override def elemEnd(pos: Int, pre: String, label: String) {
-      setEvent(ElemEnd(pre, label)); doNotify
+      setEvent(EvElemEnd(pre, label)); doNotify
     }
 
     final def elem(pos: Int, pre: String, label: String, attrs: MetaData, pscope: NamespaceBinding, nodes: NodeSeq): NodeSeq =
-      NodeSeq.Empty
+      ignore_node
 
     def procInstr(pos: Int, target: String, txt: String): NodeSeq = {
-      setEvent(ElemStart(null, "comm", null, null)); doNotify
+      setEvent(EvProcInstr(target, txt)); doNotify
     }
 
     def comment(pos: Int, txt: String): NodeSeq = {
-      setEvent(ElemStart(null, "comm", null, null)); doNotify
+      setEvent(EvComment(txt)); doNotify
     }
 
     def entityRef(pos: Int, n: String): NodeSeq = {
-      setEvent(ElemStart(null, "eref", null, null)); doNotify
+      setEvent(EvEntityRef(n)); doNotify
     }
 
     def text(pos: Int, txt:String): NodeSeq = {
-      setEvent(ElemStart(null, "tex", null, null)); doNotify
+      setEvent(EvText(txt)); doNotify
     }
 
     override def run() {
diff --git a/test/files/jvm/xmlpull.scala b/test/files/jvm/xmlpull.scala
new file mode 100644
index 0000000000..1f0e6a8497
--- /dev/null
+++ b/test/files/jvm/xmlpull.scala
@@ -0,0 +1,31 @@
+import scala.xml._
+import scala.xml.pull._
+import scala.io.Source
+
+object Test {
+
+  val src = Source.fromString("<hello><world/>!</hello>")
+
+  def main(args: Array[String]) {
+    var er = new XMLEventReader().initialize(src)
+    er.next match {
+      case EvElemStart(_, "hello", _, _) => //println("1")
+	}
+	er.next match {
+      case EvElemStart(_, "world", _, _) => //println("2")
+    }
+	er.next match {
+      case EvElemEnd(_, "world") => //println("3")
+    }
+	er.next match {
+      case EvText("!") => //println("4")
+	}
+    er.next match {
+      case EvElemEnd(_, "hello") => //println("5")
+	}
+	// you get the picture...
+	er.stop  // allow thread to be garbage-collected
+	//println("6")
+  }
+}
+
-- 
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