#!/usr/bin/env python3
'''
xpybar – xmobar replacement written in python
Copyright © 2014, 2015 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, **kwargs):
'''
Invoke the function, every `interval`:th time
@param args:*? The parameters of the function
@param kwargs:**? 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, **kwargs)
self.last_return = rc
self.counter = self.interval
self.counter -= 1
return rc
class DelayedSometimes:
'''
Function wrapper for only actually invoking
the function every n:th time, where n is a
customisable parameter, with an added
functionallity: the actual invocation will
take place at the first invocation and then
a number of invocations is required before
the second actual invocation after which
the normal interval will be used
'''
def __init__(self, function, delay, interval):
'''
Constructor
@param function:(*?)→¿R? The functiony
@param delay:int The of times needed to invoke between the first and second actual invocation
@param interval:int Invoke the function every `interval`:th time
'''
def f(*args, **kwargs):
self.function = Sometimes(function, interval, initial = delay)
self.function.last_return = function(*args, **kwargs)
return self.function.last_return
self.function = f
def __call__(self, *args, **kwargs):
'''
Invoke the function when scheduled
@param args:*? The parameters of the function
@param kwargs:**? The named parameters of the function
@return :¿R? The return value of the function, the last return if not invoked
'''
return self.function(*args, **kwargs)
class Clocked:
'''
`Sometimes` wrapper that needs explicit re-evaluation before
its `Sometimes` functionallity is invoked. That is, it needs
a selected number of explicit re-evaluation before the value
is actually re-evaluted.
The rationale for this class is that you may want to update
somethings more often than other things, periodically, but
you may also want to update other things when certain events
occur.
'''
def __init__(self, *args, **kwargs):
'''
Constructor
@param args:* Positional arguments for the `Sometimes` constructor
@param kwargs:** Keyworkd arguments for the `Sometimes` constructor
'''
self.sometimes = Sometimes(*args, **kwargs)
self.text = self.sometimes()
def __call__(self, update = False):
'''
Return the most recently evaluated value
@param update:bool Whether to re-evalute the value and return the new value
@return :¿T? The most recently evaluated value
'''
if update:
self.text = self.sometimes()
return self.text
@staticmethod
def update_all(functions):
'''
Update all elements in an iteratable that is of the type `Clocked`
@param functions:itr<¿T?> The iteratable
'''
for f in functions:
if isinstance(f, Clocked):
f(True)
