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Diffstat (limited to 'morphlib/gitindex.py')
| -rw-r--r-- | morphlib/gitindex.py | 99 |
1 files changed, 99 insertions, 0 deletions
diff --git a/morphlib/gitindex.py b/morphlib/gitindex.py new file mode 100644 index 00000000..d8de8824 --- /dev/null +++ b/morphlib/gitindex.py @@ -0,0 +1,99 @@ +# Copyright (C) 2013 Codethink Limited +# +# This program is free software; you can redistribute it and/or modify +# it under the terms of the GNU General Public License as published by +# the Free Software Foundation; version 2 of the License. +# +# This program is distributed in the hope that it will be useful, +# but WITHOUT ANY WARRANTY; without even the implied warranty of +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +# GNU General Public License for more details. +# +# You should have received a copy of the GNU General Public License along +# with this program; if not, write to the Free Software Foundation, Inc., +# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. +# +# =*= License: GPL-2 =*= + + +import collections + + +STATUS_UNTRACKED = '??' +STATUS_IGNORED = '!!' + + +class GitIndex(object): + '''An object that represents operations on the working tree. + + Index objects can be constructed with a different path to the + index file, which can be used to construct commits without + altering the working tree, index or HEAD. + + The file must either be a previously initialised index, or a + non-existant file. + + Git creates a lock file and atomically alters the index by + renaming a temporary file into place, so `index_file` must be + in a writable directory. + + ''' + + def __init__(self, gd, index_file): + self._gd = gd + self._index_file = index_file + + def _run_git(self, *args, **kwargs): + if self._index_file is not None: + kwargs['env'] = kwargs.get('env', {}) + kwargs['env']['GIT_INDEX_FILE'] = self._index_file + return self._gd._runcmd(['git'] + list(args), **kwargs) + + def _get_status(self): + '''Return git status output in a Python useful format + + This runs git status such that unusual filenames are preserved + and returns its output in a sequence of (status_code, to_path, + from_path). + + from_path is None unless the status_code says there was a + rename, in which case it is the path it was renamed from. + + Untracked and ignored changes are also included in the output, + their status codes are '??' and '!!' respectively. + + ''' + + # git status -z will NUL terminate paths, so we don't have to + # unescape the paths it outputs. Unfortunately each status entry + # can have 1 or 2 paths, so extra parsing is required. + # To handle this, we split it into NUL delimited tokens. + # The first token of an entry is the 2 character status code, + # a space, then the path. + # If our status code starts with R then it's a rename, hence + # has a second path, requiring us to pop an extra token. + status = self._run_git('status', '-z', '--ignored') + tokens = collections.deque(status.split('\0')) + while True: + tok = tokens.popleft() + # Status output is NUL terminated rather than delimited, + # and split is for delimited output. A side effect of this is + # that we get an empty token as the last output. This suits + # us fine, as it gives us a sentinel value to terminate with. + if not tok: + return + + # The first token of an entry is 2 character status, a space, + # then the path + code = tok[:2] + to_path = tok[3:] + + # If the code starts with R then it's a rename, and + # the next token says where the file was renamed from + from_path = tokens.popleft() if code[0] == 'R' else None + yield code, to_path, from_path + + def get_uncommitted_changes(self): + for code, to_path, from_path in self._get_status(): + if code not in (STATUS_UNTRACKED, STATUS_IGNORED): + yield code, to_path, from_path |