add stop build command

src/gwt/src/org/rstudio/studio/client/workbench/commands/Commands.cmd.xml

@@ -204,6 +204,8 @@ well as menu structures (for main menu and popup menus).
          <cmd refid="buildSourcePackage"/>
          <cmd refid="buildBinaryPackage"/>
          <separator/>
+         <cmd refid="stopBuild"/>
+         <separator/>
          <cmd refid="buildToolsProjectSetup"/>
       </menu>
 
@@ -1045,6 +1047,10 @@ well as menu structures (for main menu and popup menus).
         menuLabel="_Check Package"
         desc="R CMD check"/>
 
+   <cmd id="stopBuild"
+        menuLabel="Sto_p Build"
+        desc="Stop the current build"/>
+
    <cmd id="buildToolsProjectSetup"
         menuLabel="Configure Build _Tools..."
         desc="Configure build tools"/>

src/gwt/src/org/rstudio/studio/client/workbench/commands/Commands.java

@@ -245,6 +245,7 @@
    public abstract AppCommand buildSourcePackage();
    public abstract AppCommand buildBinaryPackage();
    public abstract AppCommand checkPackage();
+   public abstract AppCommand stopBuild();
    public abstract AppCommand buildToolsProjectSetup();
    public abstract AppCommand activateBuild();
 

src/gwt/src/org/rstudio/studio/client/workbench/views/buildtools/BuildPresenter.java

@@ -65,15 +65,19 @@ public BuildPresenter(Display display,
       sourceShim_ = sourceShim;
       uiPrefs_ = uiPrefs;
       eventBus_ = eventBus;
-
+      commands_ = commands;
+
       eventBus.addHandler(BuildStartedEvent.TYPE, 
                           new BuildStartedEvent.Handler()
       {  
          @Override
          public void onBuildStarted(BuildStartedEvent event)
          {
+            commands.stopBuild().setEnabled(true);
+
             view_.bringToFront();
             view_.buildStarted();
+
          }
       });
 
@@ -93,6 +97,8 @@ public void onBuildOutput(BuildOutputEvent event)
          @Override
          public void onBuildCompleted(BuildCompletedEvent event)
          {
+            commands.stopBuild().setEnabled(false);
+
             view_.bringToFront();
             view_.buildCompleted();
             if (event.getRestartR())
@@ -105,7 +111,7 @@ public void onBuildCompleted(BuildCompletedEvent event)
          @Override
          public void onClick(ClickEvent event)
          {
-            terminateBuild();
+            commands.stopBuild().execute();
          }
       });
    }
@@ -116,6 +122,10 @@ public void initialize(BuildState buildState)
       view_.showOutput(buildState.getOutput());
       if (!buildState.isRunning())
          view_.buildCompleted();
+      else
+         commands_.stopBuild().setEnabled(true);
+
+
    }
 
    public void initializeAfterRestart(BuildRestartContext context)
@@ -192,7 +202,7 @@ protected void onSuccess(Boolean response)
       }
    }
 
-   private void terminateBuild()
+   void onStopBuild()
    {
        server_.terminateBuild(new DelayedProgressRequestCallback<Boolean>(
                                                        "Terminating Build..."){
@@ -229,4 +239,5 @@ public void execute()
    private final BuildServerOperations server_;
    private final Display view_ ; 
    private final EventBus eventBus_;
+   private final Commands commands_;
 }

src/gwt/src/org/rstudio/studio/client/workbench/views/buildtools/BuildTab.java

@@ -46,6 +46,8 @@ public abstract static class Shim extends DelayLoadTabShim<BuildPresenter, Build
       @Handler
       public abstract void onBuildBinaryPackage();
       @Handler
+      public abstract void onStopBuild();
+      @Handler
       public abstract void onCheckPackage();
 
       abstract void initialize(BuildState buildState);
@@ -64,6 +66,9 @@ public BuildTab(final Shim shim,
       session_ = session;
       binder.bind(commands, shim);
 
+      // stop build always starts out disabled
+      commands.stopBuild().setEnabled(false);
+
       eventBus.addHandler(SessionInitEvent.TYPE, new SessionInitHandler() {
          public void onSessionInit(SessionInitEvent sie)
          {