Rev 3017: Add clear() to the bzrlib.progress.TaskDisplay API. in http://people.ubuntu.com/~robertc/baz2.0/nested-pb

[Robert Collins]

At http://people.ubuntu.com/~robertc/baz2.0/nested-pb

------------------------------------------------------------
revno: 3017
revision-id:robertc at robertcollins.net-20071120003348-q444p8tld0spanlp
parent: robertc at robertcollins.net-20071120002404-fwpku689n1oz7rdw
committer: Robert Collins <robertc at robertcollins.net>
branch nick: pb.simplify
timestamp: Tue 2007-11-20 11:33:48 +1100
message:
  Add clear() to the bzrlib.progress.TaskDisplay API.
modified:
  bzrlib/progress.py             progress.py-20050610070202-df9faaab791964c0
  bzrlib/tests/test_progress.py  test_progress.py-20060308160359-978c397bc79b7fda
=== modified file 'bzrlib/progress.py'
--- a/bzrlib/progress.py	2007-11-20 00:24:04 +0000
+++ b/bzrlib/progress.py	2007-11-20 00:33:48 +0000
@@ -278,6 +278,10 @@
         """Create a TaskDisplay."""
         self._task = task
 
+    def clear(self):
+        """Hide the display - the display is finished with for now."""
+        raise NotImplementedError(self.clear)
+
     def task_changed(self):
         """Update the display due to a change in the task."""
         raise NotImplementedError(self.task_changed)
@@ -289,6 +293,15 @@
     def __init__(self, task, stream):
         TaskDisplay.__init__(self, task)
         self._stream = stream
+        self._init_state()
+
+    def clear(self):
+        if self._last_message is not None:
+            self._stream.write('\n')
+            self._init_state()
+
+    def _init_state(self):
+        """Clear the internal state used for controlling output."""
         self._last_message = None
         self._last_current = None
 
@@ -309,6 +322,9 @@
 class SilentTaskDisplay(TaskDisplay):
     """A TaskDisplay that performs no output."""
 
+    def clear(self):
+        pass
+
     def task_changed(self):
         pass
 

=== modified file 'bzrlib/tests/test_progress.py'
--- a/bzrlib/tests/test_progress.py	2007-11-20 00:24:04 +0000
+++ b/bzrlib/tests/test_progress.py	2007-11-20 00:33:48 +0000
@@ -347,6 +347,12 @@
         task = CountedTask('message')
         display = SilentTaskDisplay(task)
 
+    def test_clear(self):
+        task = CountedTask('message')
+        display = SilentTaskDisplay(task)
+        # We cannot really tell if anything is output, but the API should work.
+        display.clear()
+
     def test_task_changed(self):
         task = CountedTask('message')
         display = SilentTaskDisplay(task)
@@ -361,18 +367,39 @@
         output = StringIO()
         display = DotsTaskDisplay(task, output)
 
+    def get_display(self):
+        """Get a task, output and display to test with."""
+        task = CountedTask('message')
+        output = StringIO()
+        display = DotsTaskDisplay(task, output)
+        return task, output, display
+
+    def test_clear_no_output_does_nothing(self):
+        task, output, display = self.get_display()
+        display.clear()
+        self.assertEqual('', output.getvalue())
+
+    def test_clear_after_output_emits_nl(self):
+        task, output, display = self.get_display()
+        display.task_changed()
+        display.clear()
+        self.assertEqual('message:\n', output.getvalue())
+
+    def test_task_changed_after_clear_emits_message_again(self):
+        task, output, display = self.get_display()
+        display.task_changed()
+        display.clear()
+        display.task_changed()
+        self.assertEqual('message:\nmessage:', output.getvalue())
+
     def test_task_changed_first_call(self):
-        task = CountedTask('message')
-        output = StringIO()
-        display = DotsTaskDisplay(task, output)
+        task, output, display = self.get_display()
         # The first change will display the message
         display.task_changed()
         self.assertEqual('message:', output.getvalue())
 
     def test_task_changed_no_change(self):
-        task = CountedTask('message')
-        output = StringIO()
-        display = DotsTaskDisplay(task, output)
+        task, output, display = self.get_display()
         # The first change will display the message
         display.task_changed()
         self.assertEqual('message:', output.getvalue())
@@ -382,9 +409,7 @@
         self.assertEqual('message:', output.getvalue())
 
     def test_task_changed_task_has_ticked(self):
-        task = CountedTask('message')
-        output = StringIO()
-        display = DotsTaskDisplay(task, output)
+        task, output, display = self.get_display()
         task.tick()
         # The first change will display the message only, even if the current
         # position is non-zero.