implemented unexport of pipes.

git-svn-id: https://hudson.dev.java.net/svn/hudson/trunk/hudson/main@1368 71c3de6d-444a-0410-be80-ed276b4c234a

remoting/src/main/java/hudson/remoting/Channel.java

@@ -143,13 +143,17 @@ public class Channel {
     }
 
     /*package*/ int export(Object instance) {
-        return exportedObjects.intern(instance);
+        return exportedObjects.export(instance);
     }
 
     /*package*/ Object getExportedObject(int oid) {
         return exportedObjects.get(oid);
     }
 
+    /*package*/ void unexport(int id) {
+        exportedObjects.unexport(id);
+    }
+
     /**
      * Makes a remote procedure call.
      *

remoting/src/main/java/hudson/remoting/ExportTable.java

@@ -4,7 +4,7 @@ import java.util.HashMap;
 import java.util.Map;
 
 /**
- * Manages unique ID for exported objects.
+ * Manages unique ID for exported objects, and allows look-up from IDs.
  *
  * @author Kohsuke Kawaguchi
  */
@@ -12,10 +12,24 @@ final class ExportTable<T> {
     private final Map<Integer,T> table = new HashMap<Integer,T>();
     private final Map<T,Integer> reverse = new HashMap<T,Integer>();
 
-    // id==0 is reserved for bootstrap classloader
+    /**
+     * Unique ID generator.
+     */
     private int iota = 1;
 
-    public synchronized int intern(T t) {
+    /**
+     * Exports the given object.
+     *
+     * <p>
+     * Until the object is {@link #unexport(Object) unexported}, it will
+     * not be subject to GC.
+     *
+     * @return
+     *      The assigned 'object ID'. If the object is already exported,
+     *      it will return the ID already assigned to it.
+     */
+    // TODO: the 'intern' semantics requires reference counting for proper unexport op.
+    public synchronized int export(T t) {
         if(t==null)    return 0;   // bootstrap classloader
 
         Integer id = reverse.get(t);
@@ -32,6 +46,9 @@ final class ExportTable<T> {
         return table.get(id);
     }
 
+    /**
+     * Removes the exported object from the table.
+     */
     public synchronized void unexport(T t) {
         if(t==null)     return;
         Integer id = reverse.remove(t);

remoting/src/main/java/hudson/remoting/Pipe.java

@@ -43,8 +43,6 @@ import java.util.logging.Logger;
  * to send data, instead of typed proxy object. This allows the writer to send data
  * without blocking until the arrival of the data is confirmed.
  *
- * TODO: unexport
- * 
  * @author Kohsuke Kawaguchi
  */
 public final class Pipe implements Serializable {
@@ -143,8 +141,7 @@ public final class Pipe implements Serializable {
          */
         private ByteArrayOutputStream tmp;
         /**
-         * Set to true if the stream is closed before it's connected
-         * to a remote object.
+         * Set to true if the stream is closed.
          */
         private boolean closed;
 
@@ -169,7 +166,7 @@ public final class Pipe implements Serializable {
                 write(tmp.toByteArray());
                 tmp = null;
             }
-            if(closed)
+            if(closed)  // already marked closed?
                 close();
         }
 
@@ -178,6 +175,8 @@ public final class Pipe implements Serializable {
         }
 
         public void write(byte b[], int off, int len) throws IOException {
+            if(closed)
+                throw new IOException("stream is already closed");
             if(off==0 && len==b.length)
                 write(b);
             else {
@@ -188,6 +187,8 @@ public final class Pipe implements Serializable {
         }
 
         public synchronized void write(byte b[]) throws IOException {
+            if(closed)
+                throw new IOException("stream is already closed");
             if(channel==null) {
                 if(tmp==null)
                     tmp = new ByteArrayOutputStream();
@@ -245,6 +246,7 @@ public final class Pipe implements Serializable {
 
             protected void execute(Channel channel) {
                 OutputStream os = (OutputStream) channel.getExportedObject(oid);
+                channel.unexport(oid);
                 try {
                     os.close();
                 } catch (IOException e) {
@@ -274,6 +276,7 @@ public final class Pipe implements Serializable {
         protected void execute(Channel channel) {
             try {
                 RemoteOutputStream ros = (RemoteOutputStream) channel.getExportedObject(oidRos);
+                channel.unexport(oidRos);
                 ros.connect(channel, oidPos);
             } catch (IOException e) {
                 logger.severe("Failed to connect to pipe");