In the application I am developing I have a thread that when initialized starts a suprocess by Popen redirecting the stdout to PIPE. In the run() I need to wait both on the pipe and on an event.
The output of the pipe must be outputted on a textview.
When the event is set the thread must stop returning from the run().
My solution is to
- wait on the pipe by a timeouted select.select
- then if the select returns the pipe is readable
- read a single byte from the pipe, so I am sure this reading can't block
- store the byte in a bytearray up to I receive a newline
- output the bytearray to a textviev
- testing the event
This works but reading 1 byte per time is really inefficient
I am wondering it a more efficient solutions exists.
This is a snippet of my code:
class ProcessEcho(threading.Thread):
def __init__(self,environ,command_line,textbuffer,on_process_exited_cb):
super(ProcessEcho,self).__init__()
self.textbuffer = textbuffer
self.on_process_exited_cb = on_process_exited_cb
self.popen = subprocess.Popen(command_line,stdout = subprocess.PIPE, stderr = subprocess.STDOUT,bufsize=0,env=environ)
self.exit_event = threading.Event()
self.daemon = True
self.start()
def get_pid(self):
return self.popen.pid
def stop(self):
self.exit_event.set()
def update_textbuffer(self,string):
self.textbuffer.insert(self.textbuffer.get_end_iter(),string)
def run(self):
buffer = bytearray()
while True:
rl,wl,xl = select.select([self.popen.stdout], [], [], 1)
if len(rl):
r = self.popen.stdout.read(1)
if r=='':
self.popen.communicate()
GObject.idle_add(self.on_process_exited_cb)
return
else:
buffer.append(r)
if r == "\n":
GObject.idle_add(self.update_textbuffer,str(buffer))
buffer = bytearray()
if self.exit_event.is_set():
self.popen.communicate()
GObject.idle_add(self.on_process_exited_cb)
return
