pyzmq/zmq/backend/cffi/socket.py

"""zmq Socket class"""

# Copyright (C) PyZMQ Developers
# Distributed under the terms of the Modified BSD License.

import errno as errno_mod

import zmq
from zmq.constants import SocketOption, _OptType
from zmq.error import ZMQError, _check_rc, _check_version

from ._cffi import ffi
from ._cffi import lib as C
from .message import Frame
from .utils import _retry_sys_call

nsp = new_sizet_pointer = lambda length: ffi.new('size_t*', length)


def new_uint64_pointer():
    return ffi.new('uint64_t*'), nsp(ffi.sizeof('uint64_t'))


def new_int64_pointer():
    return ffi.new('int64_t*'), nsp(ffi.sizeof('int64_t'))


def new_int_pointer():
    return ffi.new('int*'), nsp(ffi.sizeof('int'))


def new_binary_data(length):
    return ffi.new(f'char[{length:d}]'), nsp(ffi.sizeof('char') * length)


def value_uint64_pointer(val):
    return ffi.new('uint64_t*', val), ffi.sizeof('uint64_t')


def value_int64_pointer(val):
    return ffi.new('int64_t*', val), ffi.sizeof('int64_t')


def value_int_pointer(val):
    return ffi.new('int*', val), ffi.sizeof('int')


def value_binary_data(val, length):
    return ffi.new(f'char[{length + 1:d}]', val), ffi.sizeof('char') * length


ZMQ_FD_64BIT = ffi.sizeof('ZMQ_FD_T') == 8

IPC_PATH_MAX_LEN = C.get_ipc_path_max_len()


def new_pointer_from_opt(option, length=0):
    opt_type = getattr(option, "_opt_type", _OptType.int)

    if opt_type == _OptType.int64 or (ZMQ_FD_64BIT and opt_type == _OptType.fd):
        return new_int64_pointer()
    elif opt_type == _OptType.bytes:
        return new_binary_data(length)
    else:
        # default
        return new_int_pointer()


def value_from_opt_pointer(option, opt_pointer, length=0):
    try:
        option = SocketOption(option)
    except ValueError:
        # unrecognized option,
        # assume from the future,
        # let EINVAL raise
        opt_type = _OptType.int
    else:
        opt_type = option._opt_type

    if opt_type == _OptType.bytes:
        return ffi.buffer(opt_pointer, length)[:]
    else:
        return int(opt_pointer[0])


def initialize_opt_pointer(option, value, length=0):
    opt_type = getattr(option, "_opt_type", _OptType.int)
    if opt_type == _OptType.int64 or (ZMQ_FD_64BIT and opt_type == _OptType.fd):
        return value_int64_pointer(value)
    elif opt_type == _OptType.bytes:
        return value_binary_data(value, length)
    else:
        return value_int_pointer(value)


class Socket:
    context = None
    socket_type = None
    _zmq_socket = None
    _closed = None
    _ref = None
    _shadow = False
    copy_threshold = 0

    def __init__(self, context=None, socket_type=None, shadow=0, copy_threshold=None):
        if copy_threshold is None:
            copy_threshold = zmq.COPY_THRESHOLD
        self.copy_threshold = copy_threshold

        self.context = context
        if shadow:
            self._zmq_socket = ffi.cast("void *", shadow)
            self._shadow = True
        else:
            self._shadow = False
            self._zmq_socket = C.zmq_socket(context._zmq_ctx, socket_type)
        if self._zmq_socket == ffi.NULL:
            raise ZMQError()
        self._closed = False

    @property
    def underlying(self):
        """The address of the underlying libzmq socket"""
        return int(ffi.cast('size_t', self._zmq_socket))

    def _check_closed_deep(self):
        """thorough check of whether the socket has been closed,
        even if by another entity (e.g. ctx.destroy).

        Only used by the `closed` property.

        returns True if closed, False otherwise
        """
        if self._closed:
            return True
        try:
            self.get(zmq.TYPE)
        except ZMQError as e:
            if e.errno == zmq.ENOTSOCK:
                self._closed = True
                return True
            elif e.errno == zmq.ETERM:
                pass
            else:
                raise
        return False

    @property
    def closed(self):
        return self._check_closed_deep()

    def close(self, linger=None):
        rc = 0
        if not self._closed and hasattr(self, '_zmq_socket'):
            if self._zmq_socket is not None:
                if linger is not None:
                    self.set(zmq.LINGER, linger)
                rc = C.zmq_close(self._zmq_socket)
            self._closed = True
        if rc < 0:
            _check_rc(rc)

    def bind(self, address):
        if isinstance(address, str):
            address_b = address.encode('utf8')
        else:
            address_b = address
        if isinstance(address, bytes):
            address = address_b.decode('utf8')
        rc = C.zmq_bind(self._zmq_socket, address_b)
        if rc < 0:
            if IPC_PATH_MAX_LEN and C.zmq_errno() == errno_mod.ENAMETOOLONG:
                path = address.split('://', 1)[-1]
                msg = (
                    f'ipc path "{path}" is longer than {IPC_PATH_MAX_LEN} '
                    'characters (sizeof(sockaddr_un.sun_path)).'
                )
                raise ZMQError(C.zmq_errno(), msg=msg)
            elif C.zmq_errno() == errno_mod.ENOENT:
                path = address.split('://', 1)[-1]
                msg = f'No such file or directory for ipc path "{path}".'
                raise ZMQError(C.zmq_errno(), msg=msg)
            else:
                _check_rc(rc)

    def unbind(self, address):
        _check_version((3, 2), "unbind")
        if isinstance(address, str):
            address = address.encode('utf8')
        rc = C.zmq_unbind(self._zmq_socket, address)
        _check_rc(rc)

    def connect(self, address):
        if isinstance(address, str):
            address = address.encode('utf8')
        rc = C.zmq_connect(self._zmq_socket, address)
        _check_rc(rc)

    def disconnect(self, address):
        _check_version((3, 2), "disconnect")
        if isinstance(address, str):
            address = address.encode('utf8')
        rc = C.zmq_disconnect(self._zmq_socket, address)
        _check_rc(rc)

    def set(self, option, value):
        length = None
        if isinstance(value, str):
            raise TypeError("unicode not allowed, use bytes")

        try:
            option = SocketOption(option)
        except ValueError:
            # unrecognized option,
            # assume from the future,
            # let EINVAL raise
            opt_type = _OptType.int
        else:
            opt_type = option._opt_type

        if isinstance(value, bytes):
            if opt_type != _OptType.bytes:
                raise TypeError(f"not a bytes sockopt: {option}")
            length = len(value)

        c_value_pointer, c_sizet = initialize_opt_pointer(option, value, length)

        _retry_sys_call(
            C.zmq_setsockopt,
            self._zmq_socket,
            option,
            ffi.cast('void*', c_value_pointer),
            c_sizet,
        )

    def get(self, option):
        try:
            option = SocketOption(option)
        except ValueError:
            # unrecognized option,
            # assume from the future,
            # let EINVAL raise
            opt_type = _OptType.int
        else:
            opt_type = option._opt_type

        c_value_pointer, c_sizet_pointer = new_pointer_from_opt(option, length=255)

        _retry_sys_call(
            C.zmq_getsockopt, self._zmq_socket, option, c_value_pointer, c_sizet_pointer
        )

        sz = c_sizet_pointer[0]
        v = value_from_opt_pointer(option, c_value_pointer, sz)
        if (
            option != zmq.SocketOption.ROUTING_ID
            and opt_type == _OptType.bytes
            and v.endswith(b'\0')
        ):
            v = v[:-1]
        return v

    def _send_copy(self, buf, flags):
        """Send a copy of a bufferable"""
        zmq_msg = ffi.new('zmq_msg_t*')
        if not isinstance(buf, bytes):
            # cast any bufferable data to bytes via memoryview
            buf = memoryview(buf).tobytes()

        c_message = ffi.new('char[]', buf)
        rc = C.zmq_msg_init_size(zmq_msg, len(buf))
        _check_rc(rc)
        C.memcpy(C.zmq_msg_data(zmq_msg), c_message, len(buf))
        _retry_sys_call(C.zmq_msg_send, zmq_msg, self._zmq_socket, flags)
        rc2 = C.zmq_msg_close(zmq_msg)
        _check_rc(rc2)

    def _send_frame(self, frame, flags):
        """Send a Frame on this socket in a non-copy manner."""
        # Always copy the Frame so the original message isn't garbage collected.
        # This doesn't do a real copy, just a reference.
        frame_copy = frame.fast_copy()
        zmq_msg = frame_copy.zmq_msg
        _retry_sys_call(C.zmq_msg_send, zmq_msg, self._zmq_socket, flags)
        tracker = frame_copy.tracker
        frame_copy.close()
        return tracker

    def send(self, data, flags=0, copy=False, track=False):
        if isinstance(data, str):
            raise TypeError("Message must be in bytes, not a unicode object")

        if copy and not isinstance(data, Frame):
            return self._send_copy(data, flags)
        else:
            close_frame = False
            if isinstance(data, Frame):
                if track and not data.tracker:
                    raise ValueError('Not a tracked message')
                frame = data
            else:
                if self.copy_threshold:
                    buf = memoryview(data)
                    # always copy messages smaller than copy_threshold
                    if buf.nbytes < self.copy_threshold:
                        self._send_copy(buf, flags)
                        return zmq._FINISHED_TRACKER
                frame = Frame(data, track=track, copy_threshold=self.copy_threshold)
                close_frame = True

            tracker = self._send_frame(frame, flags)
            if close_frame:
                frame.close()
            return tracker

    def recv(self, flags=0, copy=True, track=False):
        if copy:
            zmq_msg = ffi.new('zmq_msg_t*')
            C.zmq_msg_init(zmq_msg)
        else:
            frame = zmq.Frame(track=track)
            zmq_msg = frame.zmq_msg

        try:
            _retry_sys_call(C.zmq_msg_recv, zmq_msg, self._zmq_socket, flags)
        except Exception:
            if copy:
                C.zmq_msg_close(zmq_msg)
            raise

        if not copy:
            return frame

        _buffer = ffi.buffer(C.zmq_msg_data(zmq_msg), C.zmq_msg_size(zmq_msg))
        _bytes = _buffer[:]
        rc = C.zmq_msg_close(zmq_msg)
        _check_rc(rc)
        return _bytes

    def monitor(self, addr, events=-1):
        """s.monitor(addr, flags)

        Start publishing socket events on inproc.
        See libzmq docs for zmq_monitor for details.

        Note: requires libzmq >= 3.2

        Parameters
        ----------
        addr : str
            The inproc url used for monitoring. Passing None as
            the addr will cause an existing socket monitor to be
            deregistered.
        events : int [default: zmq.EVENT_ALL]
            The zmq event bitmask for which events will be sent to the monitor.
        """

        _check_version((3, 2), "monitor")
        if events < 0:
            events = zmq.EVENT_ALL
        if addr is None:
            addr = ffi.NULL
        if isinstance(addr, str):
            addr = addr.encode('utf8')
        C.zmq_socket_monitor(self._zmq_socket, addr, events)


__all__ = ['Socket', 'IPC_PATH_MAX_LEN']