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asyncio (Tulip issue 110): StreamReader.read() and StreamReader.readline() now

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raise a RuntimeError, instead of using an assertion, if another coroutine is
already waiting for incoming data
This commit is contained in:
Victor Stinner 2014-01-23 17:40:03 +01:00
parent 8ce6e1100e
commit 183e347796
1 changed files with 14 additions and 7 deletions
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21
Lib/asyncio/streams.py
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@ -21,7 +21,7 @@ def open_connection(host=None, port=None, *,
"""A wrapper for create_connection() returning a (reader, writer) pair.
The reader returned is a StreamReader instance; the writer is a
StreamWriter.
StreamWriter instance.
The arguments are all the usual arguments to create_connection()
except protocol_factory; most common are positional host and port,
@ -284,6 +284,16 @@ class StreamReader:
else:
self._paused = True
def _create_waiter(self, func_name):
# StreamReader uses a future to link the protocol feed_data() method
# to a read coroutine. Running two read coroutines at the same time
# would have an unexpected behaviour. It would not possible to know
# which coroutine would get the next data.
if self._waiter is not None:
raise RuntimeError('%s() called while another coroutine is '
'already waiting for incoming data' % func_name)
return futures.Future(loop=self._loop)
@tasks.coroutine
def readline(self):
if self._exception is not None:
@ -318,8 +328,7 @@ class StreamReader:
break
if not_enough:
assert self._waiter is None
self._waiter = futures.Future(loop=self._loop)
self._waiter = self._create_waiter('readline')
try:
yield from self._waiter
finally:
@ -341,16 +350,14 @@ class StreamReader:
if n < 0:
while not self._eof:
assert not self._waiter
self._waiter = futures.Future(loop=self._loop)
self._waiter = self._create_waiter('read')
try:
yield from self._waiter
finally:
self._waiter = None
else:
if not self._byte_count and not self._eof:
assert not self._waiter
self._waiter = futures.Future(loop=self._loop)
self._waiter = self._create_waiter('read')
try:
yield from self._waiter
finally: