高階使用多執行緒
本節將包含使用多執行緒實現的一些最高階的示例。
高階印表機(記錄器)
接收列印所有內容的執行緒,並根據終端寬度修改輸出。好的部分是,當終端的寬度發生變化時,已寫入輸出也會被修改。
#!/usr/bin/env python2
import threading
import Queue
import time
import sys
import subprocess
from backports.shutil_get_terminal_size import get_terminal_size
printq = Queue.Queue()
interrupt = False
lines = []
def main():
ptt = threading.Thread(target=printer) # Turn the printer on
ptt.daemon = True
ptt.start()
# Stupid example of stuff to print
for i in xrange(1,100):
printq.put(' '.join([str(x) for x in range(1,i)])) # The actual way to send stuff to the printer
time.sleep(.5)
def split_line(line, cols):
if len(line) > cols:
new_line = ''
ww = line.split()
i = 0
while len(new_line) <= (cols - len(ww[i]) - 1):
new_line += ww[i] + ' '
i += 1
print len(new_line)
if new_line == '':
return (line, '')
return (new_line, ' '.join(ww[i:]))
else:
return (line, '')
def printer():
while True:
cols, rows = get_terminal_size() # Get the terminal dimensions
msg = '#' + '-' * (cols - 2) + '#\n' # Create the
try:
new_line = str(printq.get_nowait())
if new_line != '!@#EXIT#@!': # A nice way to turn the printer
# thread out gracefully
lines.append(new_line)
printq.task_done()
else:
printq.task_done()
sys.exit()
except Queue.Empty:
pass
# Build the new message to show and split too long lines
for line in lines:
res = line # The following is to split lines which are
# longer than cols.
while len(res) !=0:
toprint, res = split_line(res, cols)
msg += '\n' + toprint
# Clear the shell and print the new output
subprocess.check_call('clear') # Keep the shell clean
sys.stdout.write(msg)
sys.stdout.flush()
time.sleep(.5)