Docserver overhaul: Gitiles away from me.

chrome/common/extensions/docs/server2/local_git_util.py

+# Copyright 2015 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.
+
+import os
+import re
+
+from file_system import FileNotFoundError
+
+
+# This provides utilities for extracting information from the local git
+# repository to which it belongs.
+
+
+# Regex to match ls-tree output.
+_LS_TREE_REGEX = re.compile(
+    '\d+\s(?P<type>\w+)\s(?P<id>[0-9a-f]{40})\s(?P<name>.*)')
+
+
+def _GetRoot():
+  return os.path.join(os.path.dirname(os.path.realpath(__file__)),
+                      os.pardir, os.pardir, os.pardir, os.pardir, os.pardir)
+
+
+def _RelativePath(path):
+  return os.path.join(_GetRoot(), path)
+
+
+def RunGit(command, args=[]):
+  # We import subprocess symbols lazily because they aren't available on
+  # AppEngine, and the frontend may load (but should never execute) this module.
+  from subprocess import check_output
+  with open(os.devnull, 'w') as dev_null:
+    return check_output(['git', command] + args, stderr=dev_null,
+        cwd=_GetRoot())
+
+
+def ParseRevision(name):
+  return RunGit('rev-parse', [name]).rstrip()
+
+
+def GetParentRevision(revision):
+  return RunGit('show', ['-s', '--format=%P', revision]).rstrip()
+
+
+def GetRootTree(revision):
+  return RunGit('show', ['-s', '--format=%T', revision]).rstrip()
+
+
+def ListDir(path, revision='HEAD'):
+  '''Retrieves a directory listing for the specified path and optional revision
+  (default is HEAD.) Returns a list of objects with the following properties:
+
+    |type|: the type of entry; 'blob' (file) or 'tree' (directory)
+    |id|: the hash of the directory entry. This is either tree hash or blob hash
+    |name|: the name of the directory entry.
+  '''
+  from subprocess import CalledProcessError
+  try:
+    ref = '%s:%s' % (ParseRevision(revision), path.lstrip('/'))
+    listing = RunGit('ls-tree', [ref]).rstrip().splitlines()
+  except CalledProcessError:
+    raise FileNotFoundError('%s not found in revision %s' % (path, revision))
+
+  def parse_line(line):
+    return re.match(_LS_TREE_REGEX, line).groupdict()
+
+  return map(parse_line, listing)
+
+
+def ReadFile(path, revision='HEAD'):
+  '''Retrieves the contents of a file at the specified path and optional
+  revision (default is HEAD.) Returns its contents as a string.
+  '''
+  from subprocess import CalledProcessError
+  try:
+    return RunGit('show', ['%s:%s' % (ParseRevision(revision), path)])
+  except CalledProcessError:
+    raise FileNotFoundError('%s not found in revision %s' % (path, revision))