53 lines
1.7 KiB
Python
53 lines
1.7 KiB
Python
# Copyright (c) 2012 The Chromium Authors. All rights reserved.
|
|
# Use of this source code is governed by a BSD-style license that can be
|
|
# found in the LICENSE file.
|
|
"""Syncronized Standard IO Linebuffer implemented with cStringIO."""
|
|
|
|
import cStringIO
|
|
import threading
|
|
import Queue
|
|
|
|
|
|
class StdioBuffer(object):
|
|
def __init__(self, shard):
|
|
self.queue = Queue.Queue()
|
|
self.completed = 0
|
|
self.shard = shard
|
|
|
|
def _pipe_handler(self, system_pipe, program_pipe):
|
|
"""Helper method for collecting stdio output. Output is collected until
|
|
a newline is seen, at which point an event is triggered and the line is
|
|
pushed to a buffer as a (stdio, line) tuple."""
|
|
buf = cStringIO.StringIO()
|
|
pipe_running = True
|
|
while pipe_running:
|
|
char = program_pipe.read(1)
|
|
if not char and self.shard.poll() is not None:
|
|
pipe_running = False
|
|
buf.write(char)
|
|
if char == '\n' or not pipe_running:
|
|
line = buf.getvalue()
|
|
if line:
|
|
self.queue.put((system_pipe, line))
|
|
if not pipe_running:
|
|
self.queue.put((system_pipe, None))
|
|
buf.close()
|
|
buf = cStringIO.StringIO()
|
|
|
|
def handle_pipe(self, system_pipe, program_pipe):
|
|
t = threading.Thread(target=self._pipe_handler, args=[system_pipe,
|
|
program_pipe])
|
|
t.start()
|
|
return t
|
|
|
|
def readline(self):
|
|
"""Emits a tuple of (sys.stderr, line), (sys.stdout, line), or (None, None)
|
|
if the process has finished. This is a blocking call."""
|
|
while True:
|
|
(pipe, line) = self.queue.get(True)
|
|
if line:
|
|
return (pipe, line)
|
|
self.completed += 1
|
|
if self.completed >= 2:
|
|
return (None, None)
|