# Copyright (C) 2016,2017 Marcus Soll

# Copyright (C) 2016,2017 Malte Vosgerau

#

# This file is part of ClassifyHub.

#

# ClassifyHub 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, either version 3 of the License, or

# (at your option) any later version.

#

# ClassifyHub 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 ClassifyHub. If not, see <http://www.gnu.org/licenses/>.

import re

import lockfile

import logging

import random

import configserver

import multiprocessing

##

# \brief Regular expression used for URL validation and developer / repository extraction.

_URL_RE = re.compile('^(http(s)?://)?(www.)?github.com/(?P<dev>[a-zA-Z0-9\-_\.]*)/(?P<repo>[a-zA-Z0-9\-_\.]*)(?!\.git)/?$')

##

# \brief Validates if the given url exists.

#

# \return Returns if the given url exists.

def validate_url(url):

url = url.strip()

return _URL_RE.match(url) is not None

##

# \brief Extracts the developer and the repository from the given url.

#

# \return Returns the developer and the repository as tupel of strings ('dev','repo').

def get_dev_and_repo(url):

url = url.strip()

match = _URL_RE.match(url)

if match is None:

return '', ''

return match.group('dev'), match.group('repo')

##

# \brief Defines the classes the repositorys are got to be assigned to.

#

# \return Returns a list of strings with all classes.

def get_classes():

return ['DEV', 'HW', 'EDU', 'DOCS', 'WEB', 'DATA', 'OTHER']

##

# \brief Creates a dict with all classes as keys and zeros as values.

#

# \return Returns a dict with all classes as keys and zeros as values.

def get_zero_class_dict():

return {'DEV': 0,

'HW': 0,

'EDU': 0,

'DOCS': 0,

'WEB': 0,

'DATA': 0,

'OTHER': 0,

}

##

# \brief Searches the given dict for the highes value.

#

# \return Returns the highes value as string.

def get_best_class(dict):

best = -1

best_class = ''

for result_class in dict.keys():

if dict[result_class] > best:

best = dict[result_class]

best_class = result_class

return best_class

##

# \brief Checks for stale lock file and removes it.

#

# A lock file is considered stale if the file is not removed X (default: 20) seconds.

# Since nothing should take longer than 20 seconds (including a single download) this should hopefully be safe.

#

# \param lock_path Path of lockfile to check. Should be the same you give to lockfile.LockFile

# \param time Time to check. The longer the time, the longer are also the waiting times

def check_stale_lock(lock_path, time=20):

worker = multiprocessing.cpu_count()

if configserver.get('number_worker') > 0:

worker = configserver.get('number_worker')

lock = lockfile.LockFile(lock_path)

test_lock = lockfile.LockFile(lock_path + '_STALE')

while not test_lock.i_am_locking():

try:

try:

# Because this is longer then the lock timeout, we are sure that this is stale

test_lock.acquire(timeout=time + time / 5 * worker + (time / 2) * random.random())

except lockfile.LockTimeout:

test_lock.break_lock()

except Exception as e:

logging.debug('Error at locking stale test log: {}'.format(e))

pass

try:

lock.acquire(timeout=time)

lock.release()

except lockfile.LockTimeout:

logging.debug('Breaking log {}'.format(lock_path))

try:

lock.break_lock()

except lockfile.NotLocked:

pass

try:

test_lock.release()

except lockfile.NotLocked:

# Someone broke it - not bad

pass

##

# \brief Calculates the 'Levenshtein distance' between two given strings.

#

# \return Returns the distances between the two given strings as int.

def edit_distance(target, source, cost_ins=1, cost_del=1, cost_sub=1):

# Default is 'Levenshtein distance'

n = len(target)

m = len(source)

matrix = [[0 for __ in range(m + 1)] for _ in range(n + 1)]

for i in range(1, n + 1):

matrix[i][0] = matrix[i - 1][0] + cost_ins

for j in range(1, m + 1):

matrix[0][j] = matrix[0][j - 1] + cost_del

for i in range(1, n + 1):

for j in range(1, m + 1):

matrix[i][j] = min(matrix[i - 1][j] + cost_ins, matrix[i - 1][j - 1] + (0 if source[j - 1] is target[i - 1] else cost_sub), matrix[i][j - 1] + cost_del)

return matrix[n][m]