cvs commit: ant/src/main/org/apache/tools/ant Project.java

[co...@apache.org]

conor       2003/02/17 06:12:10

  Modified:    docs/manual develop.html
               src/main/org/apache/tools/ant Project.java
  Log:
  Detect listener attempts to access System.out/System.err and
  terminate with a build exception before entering an infinte loop
  
  PR:	14863
  
  Revision  Changes    Path
  1.13      +8 -0      ant/docs/manual/develop.html
  
  Index: develop.html
  ===================================================================
  RCS file: /home/cvs/ant/docs/manual/develop.html,v
  retrieving revision 1.12
  retrieving revision 1.13
  diff -u -w -u -r1.12 -r1.13
  --- develop.html	24 Jan 2003 08:55:05 -0000	1.12
  +++ develop.html	17 Feb 2003 14:12:10 -0000	1.13
  @@ -336,6 +336,14 @@
   <p>will run Ant with a listener that generates an XML representation of the build progress. This
   listener is included with Ant, as is the default listener, which generates the logging to standard output.</p>
   
  +<p><b>Note: </b>A listener must not access System.out and System.err directly since ouput on 
  +these streams is redirected by Ant's core to the build event system. Accessing these 
  +streams can cause an infinite loop in Ant. Depending on the version of Ant, this will
  +either cause the build to terminate or the Java VM to run out of Stack space. A logger, also, may 
  +not access System.out and System.err directly. It must use the streams with which it has
  +been configured.
  +</p>
  +
   <hr>
   <h2><a name="integration">Source code integration</a></h2>
   
  
  
  
  1.132     +18 -4     ant/src/main/org/apache/tools/ant/Project.java
  
  Index: Project.java
  ===================================================================
  RCS file: /home/cvs/ant/src/main/org/apache/tools/ant/Project.java,v
  retrieving revision 1.131
  retrieving revision 1.132
  diff -u -w -u -r1.131 -r1.132
  --- Project.java	10 Feb 2003 14:13:30 -0000	1.131
  +++ Project.java	17 Feb 2003 14:12:10 -0000	1.132
  @@ -254,6 +254,11 @@
       private FileUtils fileUtils;
   
       /**
  +     * Flag which catches Listeners which try to use System.out or System.err 
  +     */
  +    private boolean loggingMessage = false;
  +    
  +    /**
        * Creates a new Ant project.
        */
       public Project() {
  @@ -2055,9 +2060,18 @@
                                           int priority) {
           event.setMessage(message, priority);
           Vector listeners = getBuildListeners();
  +        synchronized(this) {
  +            if (loggingMessage) {
  +                throw new BuildException("Listener attempted to access " 
  +                    + (priority == MSG_ERR ? "System.err" : "System.out") 
  +                    + " - infinite loop terminated");
  +            }
  +            loggingMessage = true;                
           for (int i = 0; i < listeners.size(); i++) {
               BuildListener listener = (BuildListener) listeners.elementAt(i);
               listener.messageLogged(event);
  +            }
  +            loggingMessage = false;
           }
       }