Create "git cache" command.

gclient_utils.py

 # Copyright (c) 2012 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """Generic utils."""
 
 import codecs
 import logging
 import os
 import pipes
@@ skipping 473 matching lines @@
     if not retry:
       break
     print ("WARNING: subprocess '%s' in %s failed; will retry after a short "
            'nap...' % (' '.join('"%s"' % x for x in args), run_cwd))
     time.sleep(sleep_interval)
     sleep_interval *= 2
   raise subprocess2.CalledProcessError(
       rv, args, kwargs.get('cwd', None), None, None)
 
 
+class GitFilter(object):
+  """A filter_fn implementation for quieting down git output messages.
+
+  Allows a custom function to skip certain lines (predicate), and will throttle
+  the output of percentage completed lines to only output every X seconds.
+  """
+  PERCENT_RE = re.compile('.* ([0-9]{1,2})% .*')
+
+  def __init__(self, time_throttle=0, predicate=None):
+    """
+    Args:
+      time_throttle (int): GitFilter will throttle 'noisy' output (such as the
+        XX% complete messages) to only be printed at least |time_throttle|
+        seconds apart.
+      predicate (f(line)): An optional function which is invoked for every line.
+        The line will be skipped if predicate(line) returns False.
+    """
+    self.last_time = 0
+    self.time_throttle = time_throttle
+    self.predicate = predicate
+
+  def __call__(self, line):
+    # git uses an escape sequence to clear the line; elide it.
+    esc = line.find(unichr(033))
+    if esc > -1:
+      line = line[:esc]
+    if self.predicate and not self.predicate(line):
+      return
+    now = time.time()
+    match = self.PERCENT_RE.match(line)
+    if not match:
+      self.last_time = 0
+    if (now - self.last_time) >= self.time_throttle:
+      self.last_time = now
+      print line
+
+
 def FindGclientRoot(from_dir, filename='.gclient'):
   """Tries to find the gclient root."""
   real_from_dir = os.path.realpath(from_dir)
   path = real_from_dir
   while not os.path.exists(os.path.join(path, filename)):
     split_path = os.path.split(path)
     if not split_path[1]:
       return None
     path = split_path[0]
 
@@ skipping 409 matching lines @@
 
   Python on OSX 10.6 raises a NotImplementedError exception.
   """
   try:
     import multiprocessing
     return multiprocessing.cpu_count()
   except:  # pylint: disable=W0702
     # Mac OS 10.6 only
     # pylint: disable=E1101
     return int(os.sysconf('SC_NPROCESSORS_ONLN'))