progress/sync: include active number of jobs

Provide a bit more info to users that things are actively running.

Bug: https://crbug.com/gerrit/11293
Change-Id: Ie8eeaa8804d1ca71cf5c78ad850fa2d17d26208c
Reviewed-on: https://gerrit-review.googlesource.com/c/git-repo/+/297904
Reviewed-by: Michael Mortensen <mmortensen@google.com>
Tested-by: Mike Frysinger <vapier@google.com>

progress.py

@@ -34,6 +34,19 @@ class Progress(object):
     self._show = False
     self._units = units
     self._print_newline = print_newline
+    # Only show the active jobs section if we run more than one in parallel.
+    self._show_jobs = False
+    self._active = 0
+
+  def start(self, name):
+    self._active += 1
+    if not self._show_jobs:
+      self._show_jobs = self._active > 1
+    self.update(inc=0, msg='started ' + name)
+
+  def finish(self, name):
+    self.update(msg='finished ' + name)
+    self._active -= 1
 
   def update(self, inc=1, msg=''):
     self._done += inc
@@ -55,10 +68,15 @@ class Progress(object):
       sys.stderr.flush()
     else:
       p = (100 * self._done) / self._total
-      sys.stderr.write('%s\r%s: %3d%% (%d%s/%d%s)%s%s%s' % (
+      if self._show_jobs:
+        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,
           self._title,
           p,
+          jobs,
           self._done, self._units,
           self._total, self._units,
           ' ' if msg else '', msg,