Adding 'show build window on failure' feature from Issue #1

Author: jonwingfield

README.md

@@ -44,6 +44,9 @@ Set to `1` to trigger a build on save. By default, this is set to `1`. I.e., Sub
 * **filename_filter**
 SublimeOnSaveBuild matches the name of the file being saved against this regular expression to determine if a build should be triggered. By default, the setting has a value of `"\\.(css|js|sass|less|scss)$"`.
 
+* **show_build_window_on_failure_only**
+Set to `1` if you want the build window to display only upon a failed build.  The default setting is `1`.  This setting can be configured on a project level.
+
 Usage
 -----
 1. Make sure you have a build operation set up in your Sublime Text 2 project and you are able to build using `Control+B` (Linux/Windows) or `Command+B` (OS X).

SublimeOnSaveBuild.py

@@ -1,7 +1,7 @@
 import sublime
 import sublime_plugin
 import re
-
+import functools
 
 class SublimeOnSaveBuild(sublime_plugin.EventListener):
     def on_post_save(self, view):
@@ -15,10 +15,39 @@ def on_post_save(self, view):
         # Load filename filter. Again, a project level setting takes precedence.
         filename_filter = view.settings().get('filename_filter', global_settings.get('filename_filter', '*'))
 
+        # Check if we should automatically hide the build window 
+        show_build_window_on_failure_only = view.settings().get('show_build_window_on_failure_only', global_settings.get('auto_hide_build_window', True))
+
         if not should_build:
             return
 
         if not re.search(filename_filter, view.file_name()):
             return
 
+        # show the 'exec' view before building, so we can read from it afterwards
+        self.output_view = view.window().get_output_panel("exec")
+
         view.window().run_command('build')
+
+        if show_build_window_on_failure_only:
+            self.num_polls = 0
+            # immediately hide the 'exec' panel. Will show it again later if there were errors
+            view.window().run_command("hide_panel", {"panel": "output.exec"})
+            # start polling for results every 100s
+            self.poll_for_results(view)
+
+    def poll_for_results(self, view):
+        build_finished = self.output_view.find('Finished', 0) != None
+
+        if build_finished:
+            errors = self.output_view.find('Error', 0)
+            if errors != None:
+                view.window().run_command("show_panel", {"panel": "output.exec"})
+        else:            
+            if self.num_polls < 50:
+                sublime.set_timeout(functools.partial(self.poll_for_results, view), 100)
+            else:
+                # show the window if the build took longer than the specified amount
+                view.window().run_command("show_panel", {"panel": "output.exec"})
+
+        self.num_polls += 1