Merge pull request arduino#96 from gandrewstone/master

Avoid null pointer exception during compilation (race condition).

http://code.google.com/p/arduino/issues/detail?id=950

Author: damellis

app/src/processing/app/debug/Compiler.java

@@ -401,10 +401,8 @@ private void execAsynchronously(List commandList) throws RunnerException {
     boolean compiling = true;
     while (compiling) {
       try {
-        if (in.thread != null)
-          in.thread.join();
-        if (err.thread != null)
-          err.thread.join();
+        in.join();
+        err.join();
         result = process.waitFor();
         //System.out.println("result is " + result);
         compiling = false;

app/src/processing/app/debug/MessageSiphon.java

@@ -85,8 +85,15 @@ public void run() {
     }
   }
 
-  
+  // Wait until the MessageSiphon thread is complete.
+  public void join() throws java.lang.InterruptedException {
+    // Grab a temp copy in case another thread nulls the "thread" 
+    // member variable
+    Thread t = thread;
+    if (t != null) t.join();
+  }
+
   public Thread getThread() {
     return thread;
-}
+  }
 }

app/src/processing/app/debug/Sizer.java

@@ -63,10 +63,8 @@ public long computeSize() throws RunnerException {
 
       while(running) {
         try {
-          if (in.thread != null)
-            in.thread.join();
-          if (err.thread != null)
-            err.thread.join();
+          in.join();
+          err.join();
           r = process.waitFor();
           running = false;
         } catch (InterruptedException intExc) { }