/usr/lib/python3/dist-packages/paramiko/buffered_pipe.py is in python3-paramiko 2.0.0-1ubuntu1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 | # Copyright (C) 2006-2007 Robey Pointer <robeypointer@gmail.com>
#
# This file is part of paramiko.
#
# Paramiko is free software; you can redistribute it and/or modify it under the
# terms of the GNU Lesser General Public License as published by the Free
# Software Foundation; either version 2.1 of the License, or (at your option)
# any later version.
#
# Paramiko is distributed in the hope that it will be useful, but WITHOUT ANY
# WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
# A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
# details.
#
# You should have received a copy of the GNU Lesser General Public License
# along with Paramiko; if not, write to the Free Software Foundation, Inc.,
# 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
"""
Attempt to generalize the "feeder" part of a `.Channel`: an object which can be
read from and closed, but is reading from a buffer fed by another thread. The
read operations are blocking and can have a timeout set.
"""
import array
import threading
import time
from paramiko.py3compat import PY2, b
class PipeTimeout (IOError):
"""
Indicates that a timeout was reached on a read from a `.BufferedPipe`.
"""
pass
class BufferedPipe (object):
"""
A buffer that obeys normal read (with timeout) & close semantics for a
file or socket, but is fed data from another thread. This is used by
`.Channel`.
"""
def __init__(self):
self._lock = threading.Lock()
self._cv = threading.Condition(self._lock)
self._event = None
self._buffer = array.array('B')
self._closed = False
if PY2:
def _buffer_frombytes(self, data):
self._buffer.fromstring(data)
def _buffer_tobytes(self, limit=None):
return self._buffer[:limit].tostring()
else:
def _buffer_frombytes(self, data):
self._buffer.frombytes(data)
def _buffer_tobytes(self, limit=None):
return self._buffer[:limit].tobytes()
def set_event(self, event):
"""
Set an event on this buffer. When data is ready to be read (or the
buffer has been closed), the event will be set. When no data is
ready, the event will be cleared.
:param threading.Event event: the event to set/clear
"""
self._event = event
if len(self._buffer) > 0:
event.set()
else:
event.clear()
def feed(self, data):
"""
Feed new data into this pipe. This method is assumed to be called
from a separate thread, so synchronization is done.
:param data: the data to add, as a `str` or `bytes`
"""
self._lock.acquire()
try:
if self._event is not None:
self._event.set()
self._buffer_frombytes(b(data))
self._cv.notifyAll()
finally:
self._lock.release()
def read_ready(self):
"""
Returns true if data is buffered and ready to be read from this
feeder. A ``False`` result does not mean that the feeder has closed;
it means you may need to wait before more data arrives.
:return:
``True`` if a `read` call would immediately return at least one
byte; ``False`` otherwise.
"""
self._lock.acquire()
try:
if len(self._buffer) == 0:
return False
return True
finally:
self._lock.release()
def read(self, nbytes, timeout=None):
"""
Read data from the pipe. The return value is a string representing
the data received. The maximum amount of data to be received at once
is specified by ``nbytes``. If a string of length zero is returned,
the pipe has been closed.
The optional ``timeout`` argument can be a nonnegative float expressing
seconds, or ``None`` for no timeout. If a float is given, a
`.PipeTimeout` will be raised if the timeout period value has elapsed
before any data arrives.
:param int nbytes: maximum number of bytes to read
:param float timeout:
maximum seconds to wait (or ``None``, the default, to wait forever)
:return: the read data, as a `bytes`
:raises PipeTimeout:
if a timeout was specified and no data was ready before that
timeout
"""
out = bytes()
self._lock.acquire()
try:
if len(self._buffer) == 0:
if self._closed:
return out
# should we block?
if timeout == 0.0:
raise PipeTimeout()
# loop here in case we get woken up but a different thread has
# grabbed everything in the buffer.
while (len(self._buffer) == 0) and not self._closed:
then = time.time()
self._cv.wait(timeout)
if timeout is not None:
timeout -= time.time() - then
if timeout <= 0.0:
raise PipeTimeout()
# something's in the buffer and we have the lock!
if len(self._buffer) <= nbytes:
out = self._buffer_tobytes()
del self._buffer[:]
if (self._event is not None) and not self._closed:
self._event.clear()
else:
out = self._buffer_tobytes(nbytes)
del self._buffer[:nbytes]
finally:
self._lock.release()
return out
def empty(self):
"""
Clear out the buffer and return all data that was in it.
:return:
any data that was in the buffer prior to clearing it out, as a
`str`
"""
self._lock.acquire()
try:
out = self._buffer_tobytes()
del self._buffer[:]
if (self._event is not None) and not self._closed:
self._event.clear()
return out
finally:
self._lock.release()
def close(self):
"""
Close this pipe object. Future calls to `read` after the buffer
has been emptied will return immediately with an empty string.
"""
self._lock.acquire()
try:
self._closed = True
self._cv.notifyAll()
if self._event is not None:
self._event.set()
finally:
self._lock.release()
def __len__(self):
"""
Return the number of bytes buffered.
:return: number (`int`) of bytes buffered
"""
self._lock.acquire()
try:
return len(self._buffer)
finally:
self._lock.release()
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