Files
tuir/rtv/workers.py
2015-03-18 00:46:36 -07:00

95 lines
2.6 KiB
Python

import time
import sys
import os
import threading
import subprocess
def open_browser(url):
"""
Call webbrowser.open_new_tab(url) and redirect stdout/stderr to devnull.
This is a workaround to stop firefox from spewing warning messages to the
console. See http://bugs.python.org/issue22277 for a better description
of the problem.
"""
command = "import webbrowser; webbrowser.open_new_tab('%s')" % url
args = [sys.executable, '-c', command]
with open(os.devnull, 'ab+', 0) as null:
subprocess.check_call(args, stdout=null, stderr=null)
class LoadScreen(object):
"""
Display a loading dialog while waiting for a blocking action to complete.
This class spins off a seperate thread to animate the loading screen in the
background.
Usage:
#>>> loader = LoadScreen(stdscr)
#>>> with loader(...):
#>>> blocking_request(...)
"""
def __init__(self, stdscr):
self._stdscr = stdscr
self._args = None
self._animator = None
self._is_running = None
def __call__(
self,
delay=0.5,
interval=0.4,
message='Downloading',
trail='...'):
self._args = (delay, interval, message, trail)
return self
def __enter__(self):
self._animator = threading.Thread(target=self.animate, args=self._args)
self._animator.daemon = True
self._is_running = True
self._animator.start()
def __exit__(self, exc_type, exc_val, exc_tb):
self._is_running = False
self._animator.join()
# Check for timeout error
def animate(self, delay, interval, message, trail):
# Delay before starting animation to avoid wasting resources if the
# wait time is very short
start = time.time()
while (time.time() - start) < delay:
if not self._is_running:
return
message_len = len(message) + len(trail)
n_rows, n_cols = self._stdscr.getmaxyx()
s_row = (n_rows - 3) // 2
s_col = (n_cols - message_len - 1) // 2
window = self._stdscr.derwin(3, message_len+2, s_row, s_col)
while True:
for i in range(len(trail)+1):
if not self._is_running:
window.clear()
window = None
self._stdscr.refresh()
return
window.erase()
window.border()
window.addstr(1, 1, message + trail[:i])
window.refresh()
time.sleep(interval)