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#
# Licensed to the Apache Software Foundation (ASF) under one
# or more contributor license agreements. See the NOTICE file
# distributed with this work for additional information
# regarding copyright ownership. The ASF licenses this file
# to you under the Apache License, Version 2.0 (the
# "License"); you may not use this file except in compliance
# with the License. You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing,
# software distributed under the License is distributed on an
# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
# KIND, either express or implied. See the License for the
# specific language governing permissions and limitations
# under the License.
#
import struct, socket
from exceptions import Closed
from packer import Packer
from threading import RLock
from logging import getLogger
raw = getLogger("qpid.io.raw")
frm = getLogger("qpid.io.frm")
FIRST_SEG = 0x08
LAST_SEG = 0x04
FIRST_FRM = 0x02
LAST_FRM = 0x01
class Frame:
HEADER = "!2BHxBH4x"
HEADER_SIZE = struct.calcsize(HEADER)
MAX_PAYLOAD = 65535 - struct.calcsize(HEADER)
def __init__(self, flags, type, track, channel, payload):
if len(payload) > Frame.MAX_PAYLOAD:
raise ValueError("max payload size exceeded: %s" % len(payload))
self.flags = flags
self.type = type
self.track = track
self.channel = channel
self.payload = payload
def isFirstSegment(self):
return bool(FIRST_SEG & self.flags)
def isLastSegment(self):
return bool(LAST_SEG & self.flags)
def isFirstFrame(self):
return bool(FIRST_FRM & self.flags)
def isLastFrame(self):
return bool(LAST_FRM & self.flags)
def __repr__(self):
return "%s%s%s%s %s %s %s %r" % (int(self.isFirstSegment()),
int(self.isLastSegment()),
int(self.isFirstFrame()),
int(self.isLastFrame()),
self.type,
self.track,
self.channel,
self.payload)
class FramingError(Exception): pass
class Framer(Packer):
HEADER="!4s4B"
def __init__(self, sock):
self.sock = sock
self.sock_lock = RLock()
self._buf = ""
def aborted(self):
return False
def write(self, buf):
self._buf += buf
def flush(self):
self.sock_lock.acquire()
try:
self._write(self._buf)
self._buf = ""
frm.debug("FLUSHED")
finally:
self.sock_lock.release()
def _write(self, buf):
while buf:
try:
n = self.sock.send(buf)
except socket.timeout:
if self.aborted():
raise Closed()
else:
continue
raw.debug("SENT %r", buf[:n])
buf = buf[n:]
def read(self, n):
data = ""
while len(data) < n:
try:
s = self.sock.recv(n - len(data))
except socket.timeout:
if self.aborted():
raise Closed()
else:
continue
except socket.error, e:
if data != "":
raise e
else:
raise Closed()
if len(s) == 0:
raise Closed()
data += s
raw.debug("RECV %r", s)
return data
def read_header(self):
return self.unpack(Framer.HEADER)
def write_header(self, major, minor):
self.sock_lock.acquire()
try:
self.pack(Framer.HEADER, "AMQP", 1, 1, major, minor)
self.flush()
finally:
self.sock_lock.release()
def write_frame(self, frame):
self.sock_lock.acquire()
try:
size = len(frame.payload) + struct.calcsize(Frame.HEADER)
track = frame.track & 0x0F
self.pack(Frame.HEADER, frame.flags, frame.type, size, track, frame.channel)
self.write(frame.payload)
if frame.isLastSegment() and frame.isLastFrame():
self.flush()
frm.debug("SENT %s", frame)
finally:
self.sock_lock.release()
def read_frame(self):
flags, type, size, track, channel = self.unpack(Frame.HEADER)
if flags & 0xF0: raise FramingError()
payload = self.read(size - struct.calcsize(Frame.HEADER))
frame = Frame(flags, type, track, channel, payload)
frm.debug("RECV %s", frame)
return frame
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