commit 4c11aebeb934817407266787d58247e1ca802057
author Mike Frysinger <vapier@google.com> Tue Apr 19 02:30:09 2022 -0400
committer Mike Frysinger <vapier@google.com> Tue Apr 19 23:50:48 2022 +0000
tree 206022ca4322d0eaf9b89f9c3acc560e2cb5db02
parent b90a422ab692657709ed49783212f7febe445ac7

progress: optimize progress bar updates a bit

Rather than erase the entire line first then print out the new content,
print out the new content on top of the old and then erase anything we
didn't update.  This should result in a lot less flashing with faster
terminals.

Bug: https://crbug.com/gerrit/11293
Change-Id: Ie2920b0bf3d5e6f920b8631a1c406444b23cd12d
Reviewed-on: https://gerrit-review.googlesource.com/c/git-repo/+/335214
Reviewed-by: LaMont Jones <lamontjones@google.com>
Tested-by: Mike Frysinger <vapier@google.com>

progress.py

diff --git a/progress.py b/progress.py
index 43c7ad2..f9ac53a 100644
--- a/progress.py
+++ b/progress.py
@@ -24,6 +24,11 @@
 # column 0.
 CSI_ERASE_LINE = '\x1b[2K'
 
+# This will erase all content in the current line after the cursor.  This is
+# useful for partial updates & progress messages as the terminal can display
+# it better.
+CSI_ERASE_LINE_AFTER = '\x1b[K'
+
 
 def duration_str(total):
   """A less noisy timedelta.__str__.
@@ -85,10 +90,10 @@
         return
 
     if self._total <= 0:
-      sys.stderr.write('%s\r%s: %d,' % (
-          CSI_ERASE_LINE,
+      sys.stderr.write('\r%s: %d,%s' % (
           self._title,
-          self._done))
+          self._done,
+          CSI_ERASE_LINE_AFTER))
       sys.stderr.flush()
     else:
       p = (100 * self._done) / self._total
@@ -96,14 +101,14 @@
         jobs = '[%d job%s] ' % (self._active, 's' if self._active > 1 else '')
       else:
         jobs = ''
-      sys.stderr.write('%s\r%s: %2d%% %s(%d%s/%d%s)%s%s%s' % (
-          CSI_ERASE_LINE,
+      sys.stderr.write('\r%s: %2d%% %s(%d%s/%d%s)%s%s%s%s' % (
           self._title,
           p,
           jobs,
           self._done, self._units,
           self._total, self._units,
           ' ' if msg else '', msg,
+          CSI_ERASE_LINE_AFTER,
           '\n' if self._print_newline else ''))
       sys.stderr.flush()
 
@@ -113,19 +118,19 @@
 
     duration = duration_str(time() - self._start)
     if self._total <= 0:
-      sys.stderr.write('%s\r%s: %d, done in %s\n' % (
-          CSI_ERASE_LINE,
+      sys.stderr.write('\r%s: %d, done in %s%s\n' % (
           self._title,
           self._done,
-          duration))
+          duration,
+          CSI_ERASE_LINE_AFTER))
       sys.stderr.flush()
     else:
       p = (100 * self._done) / self._total
-      sys.stderr.write('%s\r%s: %3d%% (%d%s/%d%s), done in %s\n' % (
-          CSI_ERASE_LINE,
+      sys.stderr.write('\r%s: %3d%% (%d%s/%d%s), done in %s%s\n' % (
           self._title,
           p,
           self._done, self._units,
           self._total, self._units,
-          duration))
+          duration,
+          CSI_ERASE_LINE_AFTER))
       sys.stderr.flush()