lib: strictly type function return status enumerations

[babeltrace.git] / src / bindings / python / bt2 / bt2 / message_iterator.py

# The MIT License (MIT)
#
# Copyright (c) 2017 Philippe Proulx <pproulx@efficios.com>
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
# THE SOFTWARE.

from bt2 import native_bt, object, utils
import bt2.message
import collections.abc
import bt2.component
import bt2


class _MessageIterator(collections.abc.Iterator):
    def __next__(self):
        raise NotImplementedError


class _GenericMessageIterator(object._SharedObject, _MessageIterator):
    def __init__(self, ptr):
            self._current_msgs = []
            self._at = 0
            super().__init__(ptr)

    def __next__(self):
        if len(self._current_msgs) == self._at:
            status, msgs = self._get_msg_range(self._ptr)
            utils._handle_func_status(status,
                                      'unexpected error: cannot advance the message iterator')
            self._current_msgs = msgs
            self._at = 0

        msg_ptr = self._current_msgs[self._at]
        self._at += 1

        return bt2.message._create_from_ptr(msg_ptr)

    @property
    def can_seek_beginning(self):
        res = self._can_seek_beginning(self._ptr)
        return res != 0

    def seek_beginning(self):
        # Forget about buffered messages, they won't be valid after seeking..
        self._current_msgs.clear()
        self._at = 0

        status = self._seek_beginning(self._ptr)
        utils._handle_func_status(status,
                                  'cannot seek message iterator beginning')


# This is created when a component wants to iterate on one of its input ports.
class _UserComponentInputPortMessageIterator(_GenericMessageIterator):
    _get_msg_range = staticmethod(native_bt.bt2_self_component_port_input_get_msg_range)
    _get_ref = staticmethod(native_bt.self_component_port_input_message_iterator_get_ref)
    _put_ref = staticmethod(native_bt.self_component_port_input_message_iterator_put_ref)
    _can_seek_beginning = staticmethod(native_bt.self_component_port_input_message_iterator_can_seek_beginning)
    _seek_beginning = staticmethod(native_bt.self_component_port_input_message_iterator_seek_beginning)


# This is created when the user wants to iterate on a component's output port,
# from outside the graph.
class _OutputPortMessageIterator(_GenericMessageIterator):
    _get_msg_range = staticmethod(native_bt.bt2_port_output_get_msg_range)
    _get_ref = staticmethod(native_bt.port_output_message_iterator_get_ref)
    _put_ref = staticmethod(native_bt.port_output_message_iterator_put_ref)
    _can_seek_beginning = staticmethod(native_bt.port_output_message_iterator_can_seek_beginning)
    _seek_beginning = staticmethod(native_bt.port_output_message_iterator_seek_beginning)


# This is extended by the user to implement component classes in Python.  It
# is created for a given output port when an input port message iterator is
# created on the input port on the other side of the connection.  It is also
# created when an output port message iterator is created on this output port.
#
# Its purpose is to feed the messages that should go out through this output
# port.
class _UserMessageIterator(_MessageIterator):
    def __new__(cls, ptr):
        # User iterator objects are always created by the native side,
        # that is, never instantiated directly by Python code.
        #
        # The native code calls this, then manually calls
        # self.__init__() without the `ptr` argument. The user has
        # access to self.component during this call, thanks to this
        # self._ptr argument being set.
        #
        # self._ptr is NOT owned by this object here, so there's nothing
        # to do in __del__().
        self = super().__new__(cls)
        self._ptr = ptr
        return self

    def _init_from_native(self, self_output_port_ptr):
        self_output_port = bt2.port._create_self_from_ptr_and_get_ref(
            self_output_port_ptr, native_bt.PORT_TYPE_OUTPUT)
        self.__init__(self_output_port)

    def __init__(self, output_port):
        pass

    @property
    def _component(self):
        return native_bt.bt2_get_user_component_from_user_msg_iter(self._ptr)

    @property
    def addr(self):
        return int(self._ptr)

    def _finalize(self):
        pass

    def __next__(self):
        raise bt2.Stop

    def _next_from_native(self):
        # this can raise anything: it's catched by the native part
        try:
            msg = next(self)
        except StopIteration:
            raise bt2.Stop
        except:
            raise

        utils._check_type(msg, bt2.message._Message)

        # The reference we return will be given to the message array.
        # However, the `msg` Python object may stay alive, if the user has kept
        # a reference to it.  Acquire a new reference to account for that.
        msg._get_ref(msg._ptr)
        return int(msg._ptr)

    @property
    def _can_seek_beginning_from_native(self):
        # Here, we mimic the behavior of the C API:
        #
        # - If the iterator has a _can_seek_beginning attribute, read it and use
        #   that result.
        # - Otherwise, the presence or absence of a `_seek_beginning`
        #   method indicates whether the iterator can seek beginning.
        if hasattr(self, '_can_seek_beginning'):
            can_seek_beginning = self._can_seek_beginning
            utils._check_bool(can_seek_beginning)
            return can_seek_beginning
        else:
            return hasattr(self, '_seek_beginning')

    def _seek_beginning_from_native(self):
        self._seek_beginning()

    def _create_event_message(self, event_class, packet, default_clock_snapshot=None):
        utils._check_type(event_class, bt2.event_class._EventClass)
        utils._check_type(packet, bt2.packet._Packet)

        if default_clock_snapshot is not None:
            if event_class.stream_class.default_clock_class is None:
                raise ValueError('event messages in this stream must not have a default clock snapshot')

            utils._check_uint64(default_clock_snapshot)
            ptr = native_bt.message_event_create_with_default_clock_snapshot(
                self._ptr, event_class._ptr, packet._ptr, default_clock_snapshot)
        else:
            if event_class.stream_class.default_clock_class is not None:
                raise ValueError('event messages in this stream must have a default clock snapshot')

            ptr = native_bt.message_event_create(
                self._ptr, event_class._ptr, packet._ptr)

        if ptr is None:
            raise bt2.CreationError('cannot create event message object')

        return bt2.message._EventMessage(ptr)

    def _create_message_iterator_inactivity_message(self, clock_class, clock_snapshot):
        utils._check_type(clock_class, bt2.clock_class._ClockClass)
        ptr = native_bt.message_message_iterator_inactivity_create(
            self._ptr, clock_class._ptr, clock_snapshot)

        if ptr is None:
            raise bt2.CreationError('cannot create inactivity message object')

        return bt2.message._MessageIteratorInactivityMessage(ptr)

    _unknown_clock_snapshot = bt2.message._StreamActivityMessageUnknownClockSnapshot()
    _infinite_clock_snapshot = bt2.message._StreamActivityMessageInfiniteClockSnapshot()

    @staticmethod
    def _validate_stream_activity_message_default_clock_snapshot(stream, default_cs):
        isinst_infinite = isinstance(default_cs, bt2.message._StreamActivityMessageInfiniteClockSnapshot)
        isinst_unknown = isinstance(default_cs, bt2.message._StreamActivityMessageUnknownClockSnapshot)

        if utils._is_uint64(default_cs):
            pass
        elif isinst_infinite or isinst_unknown:
            if default_cs is not _UserMessageIterator._unknown_clock_snapshot and default_cs is not _UserMessageIterator._infinite_clock_snapshot:
                raise ValueError('unexpected value for default clock snapshot')
        else:
            raise TypeError("unexpected type '{}' for default clock snapshot".format(default_cs.__class__.__name__))

        if stream.cls.default_clock_class is None:
            if utils._is_uint64(default_cs):
                raise ValueError('stream activity messages in this stream cannot have a known default clock snapshot')

    def _create_stream_beginning_message(self, stream):
        utils._check_type(stream, bt2.stream._Stream)

        ptr = native_bt.message_stream_beginning_create(self._ptr, stream._ptr)
        if ptr is None:
            raise bt2.CreationError('cannot create stream beginning message object')

        return bt2.message._StreamBeginningMessage(ptr)

    def _create_stream_activity_beginning_message(self, stream,
                                                  default_clock_snapshot=_unknown_clock_snapshot):
        utils._check_type(stream, bt2.stream._Stream)
        self._validate_stream_activity_message_default_clock_snapshot(stream, default_clock_snapshot)
        ptr = native_bt.message_stream_activity_beginning_create(self._ptr, stream._ptr)

        if ptr is None:
            raise bt2.CreationError(
                'cannot create stream activity beginning message object')

        msg = bt2.message._StreamActivityBeginningMessage(ptr)
        msg._default_clock_snapshot = default_clock_snapshot
        return msg

    def _create_stream_activity_end_message(self, stream,
                                            default_clock_snapshot=_unknown_clock_snapshot):
        utils._check_type(stream, bt2.stream._Stream)
        self._validate_stream_activity_message_default_clock_snapshot(stream, default_clock_snapshot)
        ptr = native_bt.message_stream_activity_end_create(self._ptr, stream._ptr)

        if ptr is None:
            raise bt2.CreationError(
                'cannot create stream activity end message object')

        msg = bt2.message._StreamActivityEndMessage(ptr)
        msg._default_clock_snapshot = default_clock_snapshot
        return msg

    def _create_stream_end_message(self, stream):
        utils._check_type(stream, bt2.stream._Stream)

        ptr = native_bt.message_stream_end_create(self._ptr, stream._ptr)
        if ptr is None:
            raise bt2.CreationError('cannot create stream end message object')

        return bt2.message._StreamEndMessage(ptr)

    def _create_packet_beginning_message(self, packet, default_clock_snapshot=None):
        utils._check_type(packet, bt2.packet._Packet)

        if packet.stream.cls.packets_have_beginning_default_clock_snapshot:
            if default_clock_snapshot is None:
                raise ValueError("packet beginning messages in this stream must have a default clock snapshot")

            utils._check_uint64(default_clock_snapshot)
            ptr = native_bt.message_packet_beginning_create_with_default_clock_snapshot(
                self._ptr, packet._ptr, default_clock_snapshot)
        else:
            if default_clock_snapshot is not None:
                raise ValueError("packet beginning messages in this stream must not have a default clock snapshot")

            ptr = native_bt.message_packet_beginning_create(self._ptr, packet._ptr)

        if ptr is None:
            raise bt2.CreationError('cannot create packet beginning message object')

        return bt2.message._PacketBeginningMessage(ptr)

    def _create_packet_end_message(self, packet, default_clock_snapshot=None):
        utils._check_type(packet, bt2.packet._Packet)

        if packet.stream.cls.packets_have_end_default_clock_snapshot:
            if default_clock_snapshot is None:
                raise ValueError("packet end messages in this stream must have a default clock snapshot")

            utils._check_uint64(default_clock_snapshot)
            ptr = native_bt.message_packet_end_create_with_default_clock_snapshot(
                self._ptr, packet._ptr, default_clock_snapshot)
        else:
            if default_clock_snapshot is not None:
                raise ValueError("packet end messages in this stream must not have a default clock snapshot")

            ptr = native_bt.message_packet_end_create(self._ptr, packet._ptr)

        if ptr is None:
            raise bt2.CreationError('cannot create packet end message object')

        return bt2.message._PacketEndMessage(ptr)

    def _create_discarded_events_message(self, stream, count=None,
                                         beg_clock_snapshot=None,
                                         end_clock_snapshot=None):
        utils._check_type(stream, bt2.stream._Stream)

        if not stream.cls.supports_discarded_events:
            raise ValueError('stream class does not support discarded events')

        if stream.cls.discarded_events_have_default_clock_snapshots:
            if beg_clock_snapshot is None or end_clock_snapshot is None:
                raise ValueError('discarded events have default clock snapshots for this stream class')

            utils._check_uint64(beg_clock_snapshot)
            utils._check_uint64(end_clock_snapshot)
            ptr = native_bt.message_discarded_events_create_with_default_clock_snapshots(
                self._ptr, stream._ptr, beg_clock_snapshot, end_clock_snapshot)
        else:
            if beg_clock_snapshot is not None or end_clock_snapshot is not None:
                raise ValueError('discarded events have no default clock snapshots for this stream class')

            ptr = native_bt.message_discarded_events_create(
                self._ptr, stream._ptr)

        if ptr is None:
            raise bt2.CreationError('cannot discarded events message object')

        msg = bt2.message._DiscardedEventsMessage(ptr)

        if count is not None:
            msg._count = count

        return msg

    def _create_discarded_packets_message(self, stream, count=None, beg_clock_snapshot=None, end_clock_snapshot=None):
        utils._check_type(stream, bt2.stream._Stream)

        if not stream.cls.supports_discarded_packets:
            raise ValueError('stream class does not support discarded packets')

        if stream.cls.discarded_packets_have_default_clock_snapshots:
            if beg_clock_snapshot is None or end_clock_snapshot is None:
                raise ValueError('discarded packets have default clock snapshots for this stream class')

            utils._check_uint64(beg_clock_snapshot)
            utils._check_uint64(end_clock_snapshot)
            ptr = native_bt.message_discarded_packets_create_with_default_clock_snapshots(
                self._ptr, stream._ptr, beg_clock_snapshot, end_clock_snapshot)
        else:
            if beg_clock_snapshot is not None or end_clock_snapshot is not None:
                raise ValueError('discarded packets have no default clock snapshots for this stream class')

            ptr = native_bt.message_discarded_packets_create(
                self._ptr, stream._ptr)

        if ptr is None:
            raise bt2.CreationError('cannot discarded packets message object')

        msg = bt2.message._DiscardedPacketsMessage(ptr)

        if count is not None:
            msg._count = count

        return msg