From 2810cbc7784e9a21e7001c31b65af94fd9ba7a5b Mon Sep 17 00:00:00 2001
From: "Shawn O. Pearce" <sop@google.com>
Date: Sat, 18 Apr 2009 10:09:16 -0700
Subject: [PATCH] Only display a progress meter once we spend 0.5 seconds on a
 task

The point of the progress meter is to let the user know that the
task is progressing, and give them a chance to estimate when it will
be complete.  If the task completes in under 0.5 seconds then it
is sufficiently fast enough that the user doesn't need to be kept
up-to-date on its progress; in fact showing the meter may just slow
the task down waiting on the tty to redraw.

We now delay the progress meter 0.5 seconds (or 1 second if the
Python time.time() function isn't accurate enough) to avoid any
really fast tasks, like a no-op local sync.

Signed-off-by: Shawn O. Pearce <sop@google.com>
---
 progress.py | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/progress.py b/progress.py
index 98bb642..b119b37 100644
--- a/progress.py
+++ b/progress.py
@@ -14,6 +14,7 @@
 # limitations under the License.
 
 import sys
+from time import time
 from trace import IsTrace
 
 class Progress(object):
@@ -22,6 +23,8 @@ class Progress(object):
     self._total = total
     self._done = 0
     self._lastp = -1
+    self._start = time()
+    self._show = False
 
   def update(self, inc=1):
     self._done += inc
@@ -29,6 +32,12 @@ class Progress(object):
     if IsTrace():
       return
 
+    if not self._show:
+      if 0.5 <= time() - self._start:
+        self._show = True
+      else:
+        return
+
     if self._total <= 0:
       sys.stderr.write('\r%s: %d, ' % (
         self._title,
@@ -47,7 +56,7 @@ class Progress(object):
         sys.stderr.flush()
 
   def end(self):
-    if IsTrace():
+    if IsTrace() or not self._show:
       return
 
     if self._total <= 0: