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def __del__(self) -> None:
try:
if self.cb:
libvirtmod.virStreamEventRemoveCallback(self._o)
except AttributeError:
pass
if self._o is not None:
libvirtmod.virStreamFree(self._o)
self._o = None
def _dispatchStreamEventCallback(self, events: int, cbData: Dict[str, Any]) -> int:
"""
Dispatches events to python user's stream event callbacks
"""
cb = cbData["cb"]
opaque = cbData["opaque"]
cb(self, events, opaque)
return 0
def eventAddCallback(self, events: int, cb: Callable[['virStream', int, _T], None], opaque: _T) -> None:
self.cb = cb
cbData = {"stream": self, "cb": cb, "opaque": opaque}
ret = libvirtmod.virStreamEventAddCallback(self._o, events, cbData)
if ret == -1:
raise libvirtError('virStreamEventAddCallback() failed')
def recvAll(self, handler: Callable[['virStream', bytes, _T], int], opaque: _T) -> None:
"""Receive the entire data stream, sending the data to the
requested data sink. This is simply a convenient alternative
to virStreamRecv, for apps that do blocking-I/O.
A hypothetical handler function looks like:
def handler(stream, # virStream instance
buf, # string containing received data
opaque): # extra data passed to recvAll as opaque
fd = opaque
return os.write(fd, buf)
"""
while True:
got = self.recv(virStorageVol.streamBufSize)
if got == -2:
raise libvirtError("cannot use recvAll with "
"nonblocking stream")
if len(got) == 0:
break
try:
ret = handler(self, got, opaque)
if isinstance(ret, int) and ret < 0:
raise RuntimeError("recvAll handler returned %d" % ret)
except BaseException:
try:
self.abort()
except Exception:
pass
raise
def sendAll(self, handler: Callable[['virStream', int, _T], bytes], opaque: _T) -> None:
"""
Send the entire data stream, reading the data from the
requested data source. This is simply a convenient alternative
to virStreamSend, for apps that do blocking-I/O.
A hypothetical handler function looks like:
def handler(stream, # virStream instance
nbytes, # int amt of data to read
opaque): # extra data passed to recvAll as opaque
fd = opaque
return os.read(fd, nbytes)
"""
while True:
try:
got = handler(self, virStorageVol.streamBufSize, opaque)
except BaseException:
try:
self.abort()
except Exception:
pass
raise
if not got:
break
ret = self.send(got)
if ret == -2:
raise libvirtError("cannot use sendAll with "
"nonblocking stream")
def recv(self, nbytes: int) -> bytes:
"""Reads a series of bytes from the stream. This method may
block the calling application for an arbitrary amount
of time.
Errors are not guaranteed to be reported synchronously
with the call, but may instead be delayed until a
subsequent call.
On success, the received data is returned. On failure, an
exception is raised. If the stream is a NONBLOCK stream and
the request would block, integer -2 is returned.
"""
ret = libvirtmod.virStreamRecv(self._o, nbytes)
if ret is None:
raise libvirtError('virStreamRecv() failed')
return ret
def send(self, data: bytes) -> int:
"""Write a series of bytes to the stream. This method may
block the calling application for an arbitrary amount
of time. Once an application has finished sending data
it should call virStreamFinish to wait for successful
confirmation from the driver, or detect any error
This method may not be used if a stream source has been
registered
Errors are not guaranteed to be reported synchronously
with the call, but may instead be delayed until a
subsequent call.
"""
ret = libvirtmod.virStreamSend(self._o, data)
if ret == -1:
raise libvirtError('virStreamSend() failed')
return ret
def recvHole(self, flags: int = 0) -> int:
"""This method is used to determine the length in bytes
of the empty space to be created in a stream's target
file when uploading or downloading sparsely populated
files. This is the counterpart to sendHole.
"""
ret = libvirtmod.virStreamRecvHole(self._o, flags)
if ret is None:
raise libvirtError('virStreamRecvHole() failed')
return ret
def sendHole(self, length: int, flags: int = 0) -> int:
"""Rather than transmitting empty file space, this method
directs the stream target to create length bytes of empty
space. This method would be used when uploading or
downloading sparsely populated files to avoid the
needless copy of empty file space.
"""
ret = libvirtmod.virStreamSendHole(self._o, length, flags)
if ret == -1:
raise libvirtError('virStreamSendHole() failed')
return ret
def recvFlags(self, nbytes: int, flags: int = 0) -> Union[bytes, int]:
"""Reads a series of bytes from the stream. This method may
block the calling application for an arbitrary amount
of time. This is just like recv except it has flags
argument.
Errors are not guaranteed to be reported synchronously
with the call, but may instead be delayed until a
subsequent call.
On success, the received data is returned. On failure, an
exception is raised. If the stream is a NONBLOCK stream and
the request would block, integer -2 is returned.
"""
ret = libvirtmod.virStreamRecvFlags(self._o, nbytes, flags)
if ret is None:
raise libvirtError('virStreamRecvFlags() failed')
return ret
def sparseRecvAll(self, handler: Callable[['virStream', bytes, _T], Union[bytes, int]], holeHandler: Callable[['virStream', int, _T], Optional[int]], opaque: _T) -> None:
"""Receive the entire data stream, sending the data to
the requested data sink handler and calling the skip
holeHandler to generate holes for sparse stream targets.
This is simply a convenient alternative to recvFlags, for
apps that do blocking-I/O and want to preserve sparseness.
Hypothetical callbacks can look like this:
def handler(stream, # virStream instance
buf, # string containing received data
opaque): # extra data passed to sparseRecvAll as opaque
fd = opaque
return os.write(fd, buf)
def holeHandler(stream, # virStream instance
length, # number of bytes to skip
opaque): # extra data passed to sparseRecvAll as opaque
fd = opaque
cur = os.lseek(fd, length, os.SEEK_CUR)
return os.ftruncate(fd, cur) # take this extra step to
# actually allocate the hole
"""
while True:
want = virStorageVol.streamBufSize
got = self.recvFlags(want, VIR_STREAM_RECV_STOP_AT_HOLE)
if got == -2:
raise libvirtError("cannot use sparseRecvAll with "
"nonblocking stream")
elif got == -3:
length = self.recvHole()
if length is None:
self.abort()
raise RuntimeError("recvHole handler failed")
ret_hole = holeHandler(self, length, opaque)
if isinstance(ret_hole, int) and ret_hole < 0:
self.abort()
raise RuntimeError("holeHandler handler returned %d" % ret_hole)
continue
elif isinstance(got, int):
raise ValueError(got)
elif not isinstance(got, bytes):
raise TypeError(type(got))
if len(got) == 0:
break
ret_data = handler(self, got, opaque)
if isinstance(ret_data, int) and ret_data < 0:
self.abort()
raise RuntimeError("sparseRecvAll handler returned %d" % ret_data)
def sparseSendAll(self, handler: Callable[['virStream', int, _T], Union[bytes, int]], holeHandler: Callable[['virStream', _T], Tuple[bool, int]], skipHandler: Callable[['virStream', int, _T], int], opaque: _T) -> None:
"""Send the entire data stream, reading the data from the
requested data source. This is simply a convenient
alternative to virStreamSend, for apps that do
blocking-I/O and want to preserve sparseness.
Hypothetical callbacks can look like this:
def handler(stream, # virStream instance
nbytes, # int amt of data to read
opaque): # extra data passed to sparseSendAll as opaque
fd = opaque
return os.read(fd, nbytes)
def holeHandler(stream, # virStream instance
opaque): # extra data passed to sparseSendAll as opaque
fd = opaque
cur = os.lseek(fd, 0, os.SEEK_CUR)
# ... find out current section and its boundaries
# and set inData = True/False and sectionLen correspondingly
os.lseek(fd, cur, os.SEEK_SET)
return [inData, sectionLen]
def skipHandler(stream, # virStream instance
length, # number of bytes to skip
opaque): # extra data passed to sparseSendAll as opaque
fd = opaque
return os.lseek(fd, length, os.SEEK_CUR)
"""
while True:
[inData, sectionLen] = holeHandler(self, opaque)
if not inData and sectionLen > 0:
if (self.sendHole(sectionLen) < 0 or
skipHandler(self, sectionLen, opaque) < 0):
self.abort()
continue
want = virStorageVol.streamBufSize
if (want > sectionLen):
want = sectionLen
got = handler(self, want, opaque)
if isinstance(got, int) and got < 0:
self.abort()
raise RuntimeError("sparseSendAll handler returned %d" % got)
if not got:
break
assert isinstance(got, bytes)
ret = self.send(got)
if ret == -2:
raise libvirtError("cannot use sparseSendAll with "
"nonblocking stream")
|
