Added git hyper-blame, a tool that skips unwanted commits in git blame.

git_common.py

 # Copyright 2014 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.
 
 # Monkeypatch IMapIterator so that Ctrl-C can kill everything properly.
 # Derived from https://gist.github.com/aljungberg/626518
 import multiprocessing.pool
 from multiprocessing.pool import IMapIterator
 def wrapper(func):
   def wrap(self, timeout=None):
@@ skipping 263 matching lines @@
   def _inner_gen():
     yield function()
     while True:
       yield
   return _inner_gen().next
 
 
 ## Git functions
 
 
+def blame(filename, revision=None, porcelain=False, *args):
+  command = ['blame']
+  if porcelain:
+    command.append('-p')
+  if revision is not None:
+    command.append(revision)
+  command.extend(['--', filename])
+  return run(*command)
+
+
 def branch_config(branch, option, default=None):
   return config('branch.%s.%s' % (branch, option), default=default)
 
 
 def config_regexp(pattern):
   if IS_WIN: # pragma: no cover
     # this madness is because we call git.bat which calls git.exe which calls
     # bash.exe (or something to that effect). Each layer divides the number of
     # ^'s by 2.
     pattern = pattern.replace('^', '^' * 8)
@@ skipping 245 matching lines @@
     if abort:
       run_with_retcode('rebase', '--abort')  # ignore failure
     return RebaseRet(False, cpe.stdout, cpe.stderr)
 
 
 def remove_merge_base(branch):
   del_branch_config(branch, 'base')
   del_branch_config(branch, 'base-upstream')
 
 
+def repo_root():
+  """Returns the absolute path to the repository root."""
+  return run('rev-parse', '--show-toplevel')
+
+
 def root():
   return config('depot-tools.upstream', 'origin/master')
 
 
+@contextlib.contextmanager
+def less():  # pragma: no cover
+  """Runs 'less' as context manager yielding its stdin as a PIPE.
+
+  Automatically checks if sys.stdout is a non-TTY stream. If so, it avoids
+  running less and just yields sys.stdout.
+  """
+  if not sys.stdout.isatty():
+    yield sys.stdout
+    return
+
+  # Run with the same options that git uses (see setup_pager in git repo).
+  # -F: Automatically quit if the output is less than one screen.
+  # -R: Don't escape ANSI color codes.
+  # -X: Don't clear the screen before starting.
+  cmd = ('less', '-FRX')
+  try:
+    proc = subprocess2.Popen(cmd, stdin=subprocess2.PIPE)
+    yield proc.stdin
+  finally:
+    proc.stdin.close()
+    proc.wait()
+
+
 def run(*cmd, **kwargs):
   """The same as run_with_stderr, except it only returns stdout."""
   return run_with_stderr(*cmd, **kwargs)[0]
 
 
 def run_with_retcode(*cmd, **kwargs):
   """Run a command but only return the status code."""
   try:
     run(*cmd, **kwargs)
     return 0
@@ skipping 297 matching lines @@
                       ['HEAD'])
 
 
 def clone_file(repository, new_workdir, link, operation):
   if not os.path.exists(os.path.join(repository, link)):
     return
   link_dir = os.path.dirname(os.path.join(new_workdir, link))
   if not os.path.exists(link_dir):
     os.makedirs(link_dir)
   operation(os.path.join(repository, link), os.path.join(new_workdir, link))