# utils.py

# Copyright (C) 2008, 2009 Michael Trier (mtrier@gmail.com) and contributors

#

# This module is part of GitPython and is released under

# the BSD License: http://www.opensource.org/licenses/bsd-license.php

import contextlib

from functools import wraps

import getpass

import logging

import os

import platform

import subprocess

import re

import shutil

import stat

from sys import maxsize

import time

from unittest import SkipTest

from gitdb.util import (# NOQA @IgnorePep8

make_sha,

LockedFD, # @UnusedImport

file_contents_ro, # @UnusedImport

file_contents_ro_filepath, # @UnusedImport

LazyMixin, # @UnusedImport

to_hex_sha, # @UnusedImport

to_bin_sha, # @UnusedImport

bin_to_hex, # @UnusedImport

hex_to_bin, # @UnusedImport

)

from git.compat import is_win

import os.path as osp

from .exc import InvalidGitRepositoryError

# NOTE: Some of the unused imports might be used/imported by others.

# Handle once test-cases are back up and running.

# Most of these are unused here, but are for use by git-python modules so these

# don't see gitdb all the time. Flake of course doesn't like it.

__all__ = ["stream_copy", "join_path", "to_native_path_linux",

"join_path_native", "Stats", "IndexFileSHA1Writer", "Iterable", "IterableList",

"BlockingLockFile", "LockFile", 'Actor', 'get_user_id', 'assure_directory_exists',

'RemoteProgress', 'CallableRemoteProgress', 'rmtree', 'unbare_repo',

'HIDE_WINDOWS_KNOWN_ERRORS']

log = logging.getLogger(__name__)

#: We need an easy way to see if Appveyor TCs start failing,

#: so the errors marked with this var are considered "acknowledged" ones, awaiting remedy,

#: till then, we wish to hide them.

HIDE_WINDOWS_KNOWN_ERRORS = is_win and os.environ.get('HIDE_WINDOWS_KNOWN_ERRORS', True)

HIDE_WINDOWS_FREEZE_ERRORS = is_win and os.environ.get('HIDE_WINDOWS_FREEZE_ERRORS', True)

#{ Utility Methods

def unbare_repo(func):

"""Methods with this decorator raise InvalidGitRepositoryError if they

encounter a bare repository"""

@wraps(func)

def wrapper(self, *args, **kwargs):

if self.repo.bare:

raise InvalidGitRepositoryError("Method '%s' cannot operate on bare repositories" % func.__name__)

# END bare method

return func(self, *args, **kwargs)

# END wrapper

return wrapper

@contextlib.contextmanager

def cwd(new_dir):

old_dir = os.getcwd()

os.chdir(new_dir)

try:

yield new_dir

finally:

os.chdir(old_dir)

def rmtree(path):

"""Remove the given recursively.

:note: we use shutil rmtree but adjust its behaviour to see whether files that

couldn't be deleted are read-only. Windows will not remove them in that case"""

def onerror(func, path, exc_info):

# Is the error an access error ?

os.chmod(path, stat.S_IWUSR)

try:

func(path) # Will scream if still not possible to delete.

except Exception as ex:

if HIDE_WINDOWS_KNOWN_ERRORS:

raise SkipTest("FIXME: fails with: PermissionError\n {}".format(ex)) from ex

raise

return shutil.rmtree(path, False, onerror)

def rmfile(path):

"""Ensure file deleted also on *Windows* where read-only files need special treatment."""

if osp.isfile(path):

if is_win:

os.chmod(path, 0o777)

os.remove(path)

def stream_copy(source, destination, chunk_size=512 * 1024):

"""Copy all data from the source stream into the destination stream in chunks

of size chunk_size

:return: amount of bytes written"""

br = 0

while True:

chunk = source.read(chunk_size)

destination.write(chunk)

br += len(chunk)

if len(chunk) < chunk_size:

break

# END reading output stream

return br

def join_path(a, *p):

"""Join path tokens together similar to osp.join, but always use

'/' instead of possibly '\' on windows."""

path = a

for b in p:

if not b:

continue

if b.startswith('/'):

path += b[1:]

elif path == '' or path.endswith('/'):

path += b

else:

path += '/' + b

# END for each path token to add

return path

if is_win:

def to_native_path_windows(path):

return path.replace('/', '\\')

def to_native_path_linux(path):

return path.replace('\\', '/')

__all__.append("to_native_path_windows")

to_native_path = to_native_path_windows

else:

# no need for any work on linux

def to_native_path_linux(path):

return path

to_native_path = to_native_path_linux

def join_path_native(a, *p):

"""

As join path, but makes sure an OS native path is returned. This is only

needed to play it safe on my dear windows and to assure nice paths that only

use '\'"""

return to_native_path(join_path(a, *p))

def assure_directory_exists(path, is_file=False):

"""Assure that the directory pointed to by path exists.

:param is_file: If True, path is assumed to be a file and handled correctly.

Otherwise it must be a directory

:return: True if the directory was created, False if it already existed"""

if is_file:

path = osp.dirname(path)

# END handle file

if not osp.isdir(path):

os.makedirs(path, exist_ok=True)

return True

return False

def _get_exe_extensions():

PATHEXT = os.environ.get('PATHEXT', None)

return tuple(p.upper() for p in PATHEXT.split(os.pathsep)) \

if PATHEXT \

else (('.BAT', 'COM', '.EXE') if is_win else ())

def py_where(program, path=None):

# From: http://stackoverflow.com/a/377028/548792

winprog_exts = _get_exe_extensions()

def is_exec(fpath):

return osp.isfile(fpath) and os.access(fpath, os.X_OK) and (

os.name != 'nt' or not winprog_exts or any(fpath.upper().endswith(ext)

for ext in winprog_exts))

progs = []

if not path:

path = os.environ["PATH"]

for folder in path.split(os.pathsep):

folder = folder.strip('"')

if folder:

exe_path = osp.join(folder, program)

for f in [exe_path] + ['%s%s' % (exe_path, e) for e in winprog_exts]:

if is_exec(f):

progs.append(f)

return progs

def _cygexpath(drive, path):

if osp.isabs(path) and not drive:

## Invoked from `cygpath()` directly with `D:Apps\123`?

# It's an error, leave it alone just slashes)

p = path

else:

p = path and osp.normpath(osp.expandvars(osp.expanduser(path)))

if osp.isabs(p):

if drive:

# Confusing, maybe a remote system should expand vars.

p = path

else:

p = cygpath(p)

elif drive:

p = '/cygdrive/%s/%s' % (drive.lower(), p)

return p.replace('\\', '/')

_cygpath_parsers = (

## See: https://msdn.microsoft.com/en-us/library/windows/desktop/aa365247(v=vs.85).aspx

## and: https://www.cygwin.com/cygwin-ug-net/using.html#unc-paths

(re.compile(r"\\\\\?\\UNC\\([^\\]+)\\([^\\]+)(?:\\(.*))?"),

(lambda server, share, rest_path: '//%s/%s/%s' % (server, share, rest_path.replace('\\', '/'))),

False

),

(re.compile(r"\\\\\?\\(\w):[/\\](.*)"),

_cygexpath,

False

),

(re.compile(r"(\w):[/\\](.*)"),

_cygexpath,

False

),

(re.compile(r"file:(.*)", re.I),

(lambda rest_path: rest_path),

True),

(re.compile(r"(\w{2,}:.*)"), # remote URL, do nothing

(lambda url: url),

False),

)

def cygpath(path):

"""Use :meth:`git.cmd.Git.polish_url()` instead, that works on any environment."""

if not path.startswith(('/cygdrive', '//')):

for regex, parser, recurse in _cygpath_parsers:

match = regex.match(path)

if match:

path = parser(*match.groups())

if recurse:

path = cygpath(path)

break

else:

path = _cygexpath(None, path)

return path

_decygpath_regex = re.compile(r"/cygdrive/(\w)(/.*)?")

def decygpath(path):

m = _decygpath_regex.match(path)

if m:

drive, rest_path = m.groups()

path = '%s:%s' % (drive.upper(), rest_path or '')

return path.replace('/', '\\')

#: Store boolean flags denoting if a specific Git executable

#: is from a Cygwin installation (since `cache_lru()` unsupported on PY2).

_is_cygwin_cache = {}

def is_cygwin_git(git_executable):

if not is_win:

return False

#from subprocess import check_output

is_cygwin = _is_cygwin_cache.get(git_executable)

if is_cygwin is None:

is_cygwin = False

try:

git_dir = osp.dirname(git_executable)

if not git_dir:

res = py_where(git_executable)

git_dir = osp.dirname(res[0]) if res else None

## Just a name given, not a real path.

uname_cmd = osp.join(git_dir, 'uname')

process = subprocess.Popen([uname_cmd], stdout=subprocess.PIPE,

universal_newlines=True)

uname_out, _ = process.communicate()

#retcode = process.poll()

is_cygwin = 'CYGWIN' in uname_out

except Exception as ex:

log.debug('Failed checking if running in CYGWIN due to: %r', ex)

_is_cygwin_cache[git_executable] = is_cygwin

return is_cygwin

def get_user_id():

""":return: string identifying the currently active system user as name@node"""

return "%s@%s" % (getpass.getuser(), platform.node())

def finalize_process(proc, **kwargs):

"""Wait for the process (clone, fetch, pull or push) and handle its errors accordingly"""

## TODO: No close proc-streams??

proc.wait(**kwargs)

def expand_path(p, expand_vars=True):

try:

p = osp.expanduser(p)

if expand_vars:

p = osp.expandvars(p)

return osp.normpath(osp.abspath(p))

except Exception:

return None

#} END utilities

#{ Classes

class RemoteProgress(object):

"""

Handler providing an interface to parse progress information emitted by git-push

and git-fetch and to dispatch callbacks allowing subclasses to react to the progress.

"""

_num_op_codes = 9

BEGIN, END, COUNTING, COMPRESSING, WRITING, RECEIVING, RESOLVING, FINDING_SOURCES, CHECKING_OUT = \

[1 << x for x in range(_num_op_codes)]

STAGE_MASK = BEGIN | END

OP_MASK = ~STAGE_MASK

DONE_TOKEN = 'done.'

TOKEN_SEPARATOR = ', '

__slots__ = ('_cur_line',

'_seen_ops',

'error_lines', # Lines that started with 'error:' or 'fatal:'.

'other_lines') # Lines not denoting progress (i.e.g. push-infos).

re_op_absolute = re.compile(r"(remote: )?([\w\s]+):\s+()(\d+)()(.*)")

re_op_relative = re.compile(r"(remote: )?([\w\s]+):\s+(\d+)% \((\d+)/(\d+)\)(.*)")

def __init__(self):

self._seen_ops = []

self._cur_line = None

self.error_lines = []

self.other_lines = []

def _parse_progress_line(self, line):

"""Parse progress information from the given line as retrieved by git-push

or git-fetch.

- Lines that do not contain progress info are stored in :attr:`other_lines`.

- Lines that seem to contain an error (i.e. start with error: or fatal:) are stored

in :attr:`error_lines`."""

# handle

# Counting objects: 4, done.

# Compressing objects: 50% (1/2)

# Compressing objects: 100% (2/2)

# Compressing objects: 100% (2/2), done.

self._cur_line = line = line.decode('utf-8') if isinstance(line, bytes) else line

if self.error_lines or self._cur_line.startswith(('error:', 'fatal:')):

self.error_lines.append(self._cur_line)

return

# find escape characters and cut them away - regex will not work with

# them as they are non-ascii. As git might expect a tty, it will send them

last_valid_index = None

for i, c in enumerate(reversed(line)):

if ord(c) < 32:

# its a slice index

last_valid_index = -i - 1

# END character was non-ascii

# END for each character in line

if last_valid_index is not None:

line = line[:last_valid_index]

# END cut away invalid part

line = line.rstrip()

cur_count, max_count = None, None

match = self.re_op_relative.match(line)

if match is None:

match = self.re_op_absolute.match(line)

if not match:

self.line_dropped(line)

self.other_lines.append(line)

return

# END could not get match

op_code = 0

_remote, op_name, _percent, cur_count, max_count, message = match.groups()

# get operation id

if op_name == "Counting objects":

op_code |= self.COUNTING

elif op_name == "Compressing objects":

op_code |= self.COMPRESSING

elif op_name == "Writing objects":

op_code |= self.WRITING

elif op_name == 'Receiving objects':

op_code |= self.RECEIVING

elif op_name == 'Resolving deltas':

op_code |= self.RESOLVING

elif op_name == 'Finding sources':

op_code |= self.FINDING_SOURCES

elif op_name == 'Checking out files':

op_code |= self.CHECKING_OUT

else:

# Note: On windows it can happen that partial lines are sent

# Hence we get something like "CompreReceiving objects", which is

# a blend of "Compressing objects" and "Receiving objects".

# This can't really be prevented, so we drop the line verbosely

# to make sure we get informed in case the process spits out new

# commands at some point.

self.line_dropped(line)

# Note: Don't add this line to the other lines, as we have to silently

# drop it

return

# END handle op code

# figure out stage

if op_code not in self._seen_ops:

self._seen_ops.append(op_code)

op_code |= self.BEGIN

# END begin opcode

if message is None:

message = ''

# END message handling

message = message.strip()

if message.endswith(self.DONE_TOKEN):

op_code |= self.END

message = message[:-len(self.DONE_TOKEN)]

# END end message handling

message = message.strip(self.TOKEN_SEPARATOR)

self.update(op_code,

cur_count and float(cur_count),

max_count and float(max_count),

message)

def new_message_handler(self):

"""

:return:

a progress handler suitable for handle_process_output(), passing lines on to this Progress

handler in a suitable format"""

def handler(line):

return self._parse_progress_line(line.rstrip())

# end

return handler

def line_dropped(self, line):

"""Called whenever a line could not be understood and was therefore dropped."""

pass

def update(self, op_code, cur_count, max_count=None, message=''):

"""Called whenever the progress changes

:param op_code:

Integer allowing to be compared against Operation IDs and stage IDs.

Stage IDs are BEGIN and END. BEGIN will only be set once for each Operation

ID as well as END. It may be that BEGIN and END are set at once in case only

one progress message was emitted due to the speed of the operation.

Between BEGIN and END, none of these flags will be set

Operation IDs are all held within the OP_MASK. Only one Operation ID will

be active per call.

:param cur_count: Current absolute count of items

:param max_count:

The maximum count of items we expect. It may be None in case there is

no maximum number of items or if it is (yet) unknown.

:param message:

In case of the 'WRITING' operation, it contains the amount of bytes

transferred. It may possibly be used for other purposes as well.

You may read the contents of the current line in self._cur_line"""

pass

class CallableRemoteProgress(RemoteProgress):

"""An implementation forwarding updates to any callable"""

__slots__ = ('_callable')

def __init__(self, fn):

self._callable = fn

super(CallableRemoteProgress, self).__init__()

def update(self, *args, **kwargs):

self._callable(*args, **kwargs)

class Actor(object):

"""Actors hold information about a person acting on the repository. They

can be committers and authors or anything with a name and an email as

mentioned in the git log entries."""

# PRECOMPILED REGEX

name_only_regex = re.compile(r'<(.*)>')

name_email_regex = re.compile(r'(.*) <(.*?)>')

# ENVIRONMENT VARIABLES

# read when creating new commits

env_author_name = "GIT_AUTHOR_NAME"

env_author_email = "GIT_AUTHOR_EMAIL"

env_committer_name = "GIT_COMMITTER_NAME"

env_committer_email = "GIT_COMMITTER_EMAIL"

# CONFIGURATION KEYS

conf_name = 'name'

conf_email = 'email'

__slots__ = ('name', 'email')

def __init__(self, name, email):

self.name = name

self.email = email

def __eq__(self, other):

return self.name == other.name and self.email == other.email

def __ne__(self, other):

return not (self == other)

def __hash__(self):

return hash((self.name, self.email))

def __str__(self):

return self.name

def __repr__(self):

return '<git.Actor "%s <%s>">' % (self.name, self.email)

@classmethod

def _from_string(cls, string):

"""Create an Actor from a string.

:param string: is the string, which is expected to be in regular git format

John Doe <jdoe@example.com>

:return: Actor """

m = cls.name_email_regex.search(string)

if m:

name, email = m.groups()

return Actor(name, email)

else:

m = cls.name_only_regex.search(string)

if m:

return Actor(m.group(1), None)

# assume best and use the whole string as name

return Actor(string, None)

# END special case name

# END handle name/email matching

@classmethod

def _main_actor(cls, env_name, env_email, config_reader=None):

actor = Actor('', '')

user_id = None # We use this to avoid multiple calls to getpass.getuser()

def default_email():

nonlocal user_id

if not user_id:

user_id = get_user_id()

return user_id

def default_name():

return default_email().split('@')[0]

for attr, evar, cvar, default in (('name', env_name, cls.conf_name, default_name),

('email', env_email, cls.conf_email, default_email)):

try:

val = os.environ[evar]

setattr(actor, attr, val)

except KeyError:

if config_reader is not None:

setattr(actor, attr, config_reader.get_value('user', cvar, default()))

# END config-reader handling

if not getattr(actor, attr):

setattr(actor, attr, default())

# END handle name

# END for each item to retrieve

return actor

@classmethod

def committer(cls, config_reader=None):

"""

:return: Actor instance corresponding to the configured committer. It behaves

similar to the git implementation, such that the environment will override

configuration values of config_reader. If no value is set at all, it will be

generated

:param config_reader: ConfigReader to use to retrieve the values from in case

they are not set in the environment"""

return cls._main_actor(cls.env_committer_name, cls.env_committer_email, config_reader)

@classmethod

def author(cls, config_reader=None):

"""Same as committer(), but defines the main author. It may be specified in the environment,

but defaults to the committer"""

return cls._main_actor(cls.env_author_name, cls.env_author_email, config_reader)

class Stats(object):

"""

Represents stat information as presented by git at the end of a merge. It is

created from the output of a diff operation.

``Example``::

c = Commit( sha1 )

s = c.stats

s.total # full-stat-dict

s.files # dict( filepath : stat-dict )

``stat-dict``

A dictionary with the following keys and values::

deletions = number of deleted lines as int

insertions = number of inserted lines as int

lines = total number of lines changed as int, or deletions + insertions

``full-stat-dict``

In addition to the items in the stat-dict, it features additional information::

files = number of changed files as int"""

__slots__ = ("total", "files")

def __init__(self, total, files):

self.total = total

self.files = files

@classmethod

def _list_from_string(cls, repo, text):

"""Create a Stat object from output retrieved by git-diff.

:return: git.Stat"""

hsh = {'total': {'insertions': 0, 'deletions': 0, 'lines': 0, 'files': 0}, 'files': {}}

for line in text.splitlines():

(raw_insertions, raw_deletions, filename) = line.split("\t")

insertions = raw_insertions != '-' and int(raw_insertions) or 0

deletions = raw_deletions != '-' and int(raw_deletions) or 0

hsh['total']['insertions'] += insertions

hsh['total']['deletions'] += deletions

hsh['total']['lines'] += insertions + deletions

hsh['total']['files'] += 1

hsh['files'][filename.strip()] = {'insertions': insertions,

'deletions': deletions,

'lines': insertions + deletions}

return Stats(hsh['total'], hsh['files'])

class IndexFileSHA1Writer(object):

"""Wrapper around a file-like object that remembers the SHA1 of

the data written to it. It will write a sha when the stream is closed

or if the asked for explicitly using write_sha.

Only useful to the indexfile

:note: Based on the dulwich project"""

__slots__ = ("f", "sha1")

def __init__(self, f):

self.f = f

self.sha1 = make_sha(b"")

def write(self, data):

self.sha1.update(data)

return self.f.write(data)

def write_sha(self):

sha = self.sha1.digest()

self.f.write(sha)

return sha

def close(self):

sha = self.write_sha()

self.f.close()

return sha

def tell(self):

return self.f.tell()

class LockFile(object):

"""Provides methods to obtain, check for, and release a file based lock which

should be used to handle concurrent access to the same file.

As we are a utility class to be derived from, we only use protected methods.

Locks will automatically be released on destruction"""

__slots__ = ("_file_path", "_owns_lock")

def __init__(self, file_path):

self._file_path = file_path

self._owns_lock = False

def __del__(self):

self._release_lock()

def _lock_file_path(self):

""":return: Path to lockfile"""

return "%s.lock" % (self._file_path)

def _has_lock(self):

""":return: True if we have a lock and if the lockfile still exists

:raise AssertionError: if our lock-file does not exist"""

return self._owns_lock

def _obtain_lock_or_raise(self):

"""Create a lock file as flag for other instances, mark our instance as lock-holder

:raise IOError: if a lock was already present or a lock file could not be written"""

if self._has_lock():

return

lock_file = self._lock_file_path()

if osp.isfile(lock_file):

raise IOError("Lock for file %r did already exist, delete %r in case the lock is illegal" %

(self._file_path, lock_file))

try:

flags = os.O_WRONLY | os.O_CREAT | os.O_EXCL

if is_win:

flags |= os.O_SHORT_LIVED

fd = os.open(lock_file, flags, 0)

os.close(fd)

except OSError as e:

raise IOError(str(e)) from e

self._owns_lock = True

def _obtain_lock(self):

"""The default implementation will raise if a lock cannot be obtained.

Subclasses may override this method to provide a different implementation"""

return self._obtain_lock_or_raise()

def _release_lock(self):

"""Release our lock if we have one"""

if not self._has_lock():

return

# if someone removed our file beforhand, lets just flag this issue

# instead of failing, to make it more usable.

lfp = self._lock_file_path()

try:

rmfile(lfp)

except OSError:

pass

self._owns_lock = False

class BlockingLockFile(LockFile):

"""The lock file will block until a lock could be obtained, or fail after

a specified timeout.

:note: If the directory containing the lock was removed, an exception will

be raised during the blocking period, preventing hangs as the lock

can never be obtained."""

__slots__ = ("_check_interval", "_max_block_time")

def __init__(self, file_path, check_interval_s=0.3, max_block_time_s=maxsize):

"""Configure the instance

:param check_interval_s:

Period of time to sleep until the lock is checked the next time.

By default, it waits a nearly unlimited time

:param max_block_time_s: Maximum amount of seconds we may lock"""

super(BlockingLockFile, self).__init__(file_path)

self._check_interval = check_interval_s

self._max_block_time = max_block_time_s

def _obtain_lock(self):

"""This method blocks until it obtained the lock, or raises IOError if

it ran out of time or if the parent directory was not available anymore.

If this method returns, you are guaranteed to own the lock"""

starttime = time.time()

maxtime = starttime + float(self._max_block_time)

while True:

try:

super(BlockingLockFile, self)._obtain_lock()

except IOError as e:

# synity check: if the directory leading to the lockfile is not

# readable anymore, raise an exception

curtime = time.time()

if not osp.isdir(osp.dirname(self._lock_file_path())):

msg = "Directory containing the lockfile %r was not readable anymore after waiting %g seconds" % (

self._lock_file_path(), curtime - starttime)

raise IOError(msg) from e

# END handle missing directory

if curtime >= maxtime:

msg = "Waited %g seconds for lock at %r" % (maxtime - starttime, self._lock_file_path())

raise IOError(msg) from e

# END abort if we wait too long

time.sleep(self._check_interval)

else:

break

# END endless loop

class IterableList(list):

"""

List of iterable objects allowing to query an object by id or by named index::

heads = repo.heads

heads.master

heads['master']

heads[0]

It requires an id_attribute name to be set which will be queried from its

contained items to have a means for comparison.

A prefix can be specified which is to be used in case the id returned by the

items always contains a prefix that does not matter to the user, so it

can be left out."""

__slots__ = ('_id_attr', '_prefix')

def __new__(cls, id_attr, prefix=''):

return super(IterableList, cls).__new__(cls)

def __init__(self, id_attr, prefix=''):

self._id_attr = id_attr

self._prefix = prefix

def __contains__(self, attr):

# first try identity match for performance

try:

rval = list.__contains__(self, attr)

if rval:

return rval

except (AttributeError, TypeError):

pass

# END handle match

# otherwise make a full name search

try:

getattr(self, attr)

return True

except (AttributeError, TypeError):

return False

# END handle membership

def __getattr__(self, attr):

attr = self._prefix + attr

for item in self:

if getattr(item, self._id_attr) == attr:

return item

# END for each item

return list.__getattribute__(self, attr)

def __getitem__(self, index):

if isinstance(index, int):

return list.__getitem__(self, index)

try:

return getattr(self, index)

except AttributeError as e:

raise IndexError("No item found with id %r" % (self._prefix + index)) from e

# END handle getattr

def __delitem__(self, index):

delindex = index

if not isinstance(index, int):

delindex = -1

name = self._prefix + index

for i, item in enumerate(self):

if getattr(item, self._id_attr) == name:

delindex = i

break

# END search index

# END for each item

if delindex == -1:

raise IndexError("Item with name %s not found" % name)

# END handle error

# END get index to delete

list.__delitem__(self, delindex)

class Iterable(object):

"""Defines an interface for iterable items which is to assure a uniform

way to retrieve and iterate items within the git repository"""

__slots__ = ()

_id_attribute_ = "attribute that most suitably identifies your instance"

@classmethod

def list_items(cls, repo, *args, **kwargs):

"""

Find all items of this type - subclasses can specify args and kwargs differently.

If no args are given, subclasses are obliged to return all items if no additional

arguments arg given.

:note: Favor the iter_items method as it will

:return:list(Item,...) list of item instances"""

out_list = IterableList(cls._id_attribute_)

out_list.extend(cls.iter_items(repo, *args, **kwargs))

return out_list

@classmethod

def iter_items(cls, repo, *args, **kwargs):

"""For more information about the arguments, see list_items

:return: iterator yielding Items"""

raise NotImplementedError("To be implemented by Subclass")

#} END classes

class NullHandler(logging.Handler):

def emit(self, record):

pass