#!/usr/bin/env python3
'''
xpybar – xmobar replacement written in python
Copyright © 2014 Mattias Andrée (maandree@member.fsf.org)
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, either version 3 of the License, or
(at your option) any later version.
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, see <http://www.gnu.org/licenses/>.
'''
import sys
import time
import threading
import subprocess
def async(target, name = None, group = None):
'''
Start a function asynchronously
@param target:()→void The function
@param name:str? The name of the thread
@return :Thread A running deamon-thread running `target`, with the name `name`
'''
t = threading.Thread(target = target, name = name)
t.setDaemon(True)
t.start()
return t
def watch(interval, target, delay = 0):
'''
Run a function periodically forever
@param interval:float The number of seconds to sleep between invocatons
@param target:()→void The function
@param delay:float Number of extra seconds to wait the first time
'''
if not delay == 0:
time.sleep(delay)
while True:
target()
time.sleep(interval)
def forever(target, delay = 0):
'''
Run a function continuously forever
@param target:()→void The function
@param delay:float Number of extra seconds to wait the first time
'''
if not delay == 0:
time.sleep(delay)
while True:
target()
def spawn(*command):
'''
Spawn an external process
@param command:*str The command line
@return :istream The process's stdout
'''
proc = subprocess.Popen(list(command), stderr = sys.stderr, stdout = subprocess.PIPE)
return proc.stdout
def spawn_read(*command):
'''
Spawn an external process and returns its output
@param command:*str The command line
@return :str The process's output to stdout, without the final LF
'''
proc = subprocess.Popen(list(command), stderr = sys.stderr, stdout = subprocess.PIPE)
out = proc.stdout.read().decode('utf-8', 'replace')
if out.endswith('\n'):
out = out[:-1]
return out
def reduce(f, items):
'''
https://en.wikipedia.org/wiki/Fold_(higher-order_function)
@param f:(¿E?, ¿E?)→¿E? The function
@param item:itr<¿E?> The input
@return ¿E?? The output, `None` if `item` is empty
'''
if len(items) == 0:
return None
rc = items[0]
for i in range(1, len(items)):
rc = f(rc, items[i])
return rc
class Sometimes:
'''
Function wrapper for only actually invoking
the function every n:th time, where n is a
customisable parameter
'''
def __init__(self, function, interval, initial = 0):
'''
Constructor
@param function:(*?)→¿R? The function
@param interval:int Invoke the function every `interval`:th time
@param initial:int The of times needed to invoke before actual invocation
'''
self.function = function
self.interval = interval
self.counter = initial
self.last_return = None
def __call__(self, *args, **kargs):
'''
Invoke the function, every `interval`:th time
@param args:*? The parameters of the function
@param kargs:**? The named parameters of the function
@return :¿R? The return value of the function, the last return if not invoked
'''
rc = self.last_return
if self.counter == 0:
rc = self.function(*args, **kargs)
self.last_return = rc
self.counter = self.interval
self.counter -= 1
return rc
