Defer resize handling when when threaded

doc/spelling_wordlist.txt

@@ -3,6 +3,7 @@ iterable
 iterables
 natively
 programmatically
+resize
 resizing
 stdout
 stderr

enlighten/_manager.py

@@ -15,6 +15,7 @@
 from collections import OrderedDict
 import signal
 import sys
+import threading
 import time
 
 from enlighten._counter import Counter
@@ -36,6 +37,8 @@ class Manager(object):
             below. (Default: :py:data:`None`)
         enabled(bool): Status (Default: True)
         no_resize(bool): Disable resizing support
+        threaded(bool): When True resize handling is deferred until next write (Default: False
+            unless multiple threads are detected)
         kwargs(Dict[str, Any]): Any additional :py:term:`keyword arguments<keyword argument>`
             will be used as default values when :py:meth:`counter` is called.
 
@@ -70,6 +73,7 @@ def __init__(self, stream=None, counter_class=Counter, **kwargs):
         self.enabled = kwargs.get('enabled', True)  # Double duty for counters
         self.no_resize = kwargs.pop('no_resize', False)
         self.set_scroll = kwargs.pop('set_scroll', True)
+        self.threaded = kwargs.pop('threaded', threading.active_count() > 1)
         self.term = Terminal(stream=self.stream)
 
         # Set up companion stream
@@ -264,9 +268,14 @@ def _stage_resize(self, *args, **kwarg):  # pylint: disable=unused-argument
         # Set semaphore to trigger resize on next write
         self._resize = True
 
-        # Reset update time to avoid any delay in resize
-        for counter in self.counters:
-            counter.last_update = 0
+        if self.threaded:
+            # Reset update time to avoid any delay in resize
+            for counter in self.counters:
+                counter.last_update = 0
+
+        else:
+            # If not threaded, handle resize now
+            self._resize_handler()
 
     def _resize_handler(self):
         """
@@ -290,10 +299,12 @@ def _resize_handler(self):
             if newHeight < self.height:
                 term.move_to(0, max(0, newHeight - self.scroll_offset))
                 self.stream.write(u'\n' * (2 * max(self.counters.values())))
+            elif newHeight > self.height and self.threaded:
+                term.move_to(0, newHeight)
+                self.stream.write(u'\n' * (self.scroll_offset - 1))
 
-            if newWidth < self.width:
-                term.move_to(0, max(0, newHeight - self.scroll_offset))
-                self.stream.write(term.clear_eos)
+            term.move_to(0, max(0, newHeight - self.scroll_offset))
+            self.stream.write(term.clear_eos)
 
             self.width = newWidth
             self._set_scroll_area(force=True)

tests/test_manager.py

@@ -583,7 +583,7 @@ def test_stop_position_1(self):
             manager.stop()
             self.assertTrue(termfeed.called)
 
-    def test_resize_handler(self):
+    def test_resize(self):
         """
         Resize lock must be False for handler to run
         Terminal size is cached unless resize handler runs
@@ -600,7 +600,7 @@ def test_resize_handler(self):
 
             manager.resize_lock = True
             with mock.patch('enlighten._manager.Manager._set_scroll_area') as ssa:
-                manager._resize_handler()
+                manager._stage_resize()
                 self.assertFalse(ssa.called)
 
             self.assertEqual(manager.width, 80)
@@ -624,11 +624,11 @@ def test_resize_handler(self):
 
             self.assertEqual(counter3.calls, ['refresh(flush=False, elapsed=None)'])
 
-    def test_resize(self):
+    def test_resize_threaded(self):
         """
-        Test a resize event
+        Test a resize event threading behavior
         """
-        manager = _manager.Manager(stream=self.tty.stdout, counter_class=MockCounter)
+        manager = _manager.Manager(stream=self.tty.stdout, counter_class=MockCounter, threaded=True)
         counter3 = MockCounter(manager=manager)
         counter3.last_update = time.time()
         manager.counters[counter3] = 3
@@ -658,10 +658,10 @@ def test_resize(self):
             self.assertFalse(manager._resize)
             self.assertEqual(counter3.calls, ['refresh(flush=False, elapsed=None)'])
 
-    def test_resize_handler_height_only(self):
+    def test_resize_handler_height_less(self):
 
         with mock.patch('%s.height' % TERMINAL, new_callable=mock.PropertyMock) as mockheight:
-            mockheight.side_effect = [25, 23, 28, 20, 20]
+            mockheight.side_effect = [25, 23]
 
             manager = _manager.Manager(stream=self.tty.stdout, counter_class=MockCounter)
             counter3 = MockCounter(manager=manager)
@@ -681,6 +681,33 @@ def test_resize_handler_height_only(self):
 
             self.assertEqual(counter3.calls, ['refresh(flush=False, elapsed=None)'])
 
+    def test_resize_handler_height_greater_threaded(self):
+
+        with mock.patch('%s.height' % TERMINAL, new_callable=mock.PropertyMock) as mockheight:
+            mockheight.side_effect = [25, 27]
+
+            manager = _manager.Manager(stream=self.tty.stdout, counter_class=MockCounter,
+                                       threaded=True)
+            counter3 = MockCounter(manager=manager)
+            manager.counters[counter3] = 3
+            manager.scroll_offset = 4
+            term = manager.term
+
+            with mock.patch('enlighten._manager.Manager._set_scroll_area') as ssa:
+                manager._resize_handler()
+            self.assertEqual(ssa.call_count, 1)
+
+            # Height is set in _set_scroll_area which is mocked
+            self.assertEqual(manager.height, 25)
+
+            self.tty.stdout.write(u'X\n')
+            self.assertEqual(self.tty.stdread.readline(), term.move(27, 0) + '\n')
+            self.assertEqual(self.tty.stdread.readline(), '\n')
+            self.assertEqual(self.tty.stdread.readline(), '\n')
+            self.assertEqual(self.tty.stdread.readline(), term.move(23, 0) + term.clear_eos + 'X\n')
+
+            self.assertEqual(counter3.calls, ['refresh(flush=False, elapsed=None)'])
+
     def test_disable(self):
         mgr = _manager.Manager(stream=self.tty.stdout, enabled=False)
         self.assertFalse(mgr.enabled)