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authorFlorent Le Coz <louiz@louiz.org>2011-11-09 01:23:35 +0100
committerFlorent Le Coz <louiz@louiz.org>2011-11-09 01:23:35 +0100
commitad0b3b41ecc0003f3d5b4fdb9799b6e325127e1f (patch)
tree3f2bbf1be7f753f1c7495f0a60833f469e7f10a7 /src/fifo.py
parent7fadb35fe2e7932a0a4aa6a8184ab6b186669edc (diff)
parent03999f1ef08036b7ea25e2239cf7b6bcdb4d76cc (diff)
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Merge branch 'plugins'
Conflicts: README src/core.py src/tabs.py
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+# Copyright 2011 Florent Le Coz <louiz@louiz.org>
+#
+# This file is part of Poezio.
+#
+# Poezio is free software: you can redistribute it and/or modify
+# it under the terms of the zlib license. See the COPYING file.
+
+"""
+Defines the Fifo class
+"""
+
+import logging
+log = logging.getLogger(__name__)
+
+import os
+import threading
+
+class OpenTrick(threading.Thread):
+ """
+ A threaded trick to make the open for writing succeed.
+ A fifo cannot be opened for writing if it has not been
+ yet opened by the other hand for reading.
+ So, we just open the fifo for reading and close it
+ immediately afterwards.
+ Once that is done, we can freely keep the fifo open for
+ writing and write things in it. The writing can fail if
+ there’s still nothing reading that fifo, but we just yell
+ an error in that case.
+ """
+ def __init__(self, path):
+ threading.Thread.__init__(self)
+ self.path = path
+
+ def run(self):
+ open(self.path, 'r').close()
+
+
+class Fifo(object):
+ """
+ Just a simple file handler, writing and reading in a fifo.
+ Mode is either 'r' or 'w', just like the mode for the open()
+ function.
+ """
+ def __init__(self, path, mode):
+ self.trick = None
+ if not os.path.exists(path):
+ os.mkfifo(path)
+ if mode == 'w':
+ self.trick = OpenTrick(path)
+ # that thread will wait until we open it for writing
+ self.trick.start()
+ self.fd = open(path, mode)
+
+ def write(self, data):
+ """
+ Try to write on the fifo. If that fails, this means
+ that nothing has that fifo opened, so the writing is useless,
+ so we just return (and display an error telling that, somewhere).
+ """
+ self.fd.write(data)
+ self.fd.flush()
+
+ def readline(self):
+ return self.fd.readline()
+
+ def __del__(self):
+ try:
+ self.fd.close()
+ except:
+ pass