bt2: add `_Trace.cls` property

[babeltrace.git] / bindings / python / bt2 / bt2 / trace.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
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# 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.
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# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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# THE SOFTWARE.

from bt2 import native_bt, object, utils
import bt2.field_class
import collections.abc
import bt2.value
import bt2.stream
import bt2.trace_class
import bt2
import functools


def _trace_destruction_listener_from_native(user_listener, trace_ptr):
    trace = bt2.trace._Trace._create_from_ptr_and_get_ref(trace_ptr)
    user_listener(trace)


class _Trace(object._SharedObject, collections.abc.Mapping):
    _get_ref = staticmethod(native_bt.trace_get_ref)
    _put_ref = staticmethod(native_bt.trace_put_ref)

    def __len__(self):
        count = native_bt.trace_get_stream_count(self._ptr)
        assert count >= 0
        return count

    def __getitem__(self, id):
        utils._check_uint64(id)

        stream_ptr = native_bt.trace_borrow_stream_by_id_const(self._ptr, id)

        if stream_ptr is None:
            raise KeyError(id)

        return bt2.stream._Stream._create_from_ptr_and_get_ref(stream_ptr)

    def __iter__(self):
        for idx in range(len(self)):
            stream_ptr = native_bt.trace_borrow_stream_by_index_const(self._ptr, idx)
            assert stream_ptr is not None

            id = native_bt.stream_get_id(stream_ptr)
            assert id >= 0

            yield id

    @property
    def cls(self):
        trace_class_ptr = native_bt.trace_borrow_class(self._ptr)
        assert trace_class_ptr is not None
        return bt2.trace_class._TraceClass._create_from_ptr_and_get_ref(trace_class_ptr)

    @property
    def name(self):
        return native_bt.trace_get_name(self._ptr)

    def _name(self, name):
        utils._check_str(name)
        ret = native_bt.trace_set_name(self._ptr, name)
        utils._handle_ret(ret, "cannot set trace class object's name")

    _name = property(fset=_name)

    def create_stream(self, stream_class, id=None, name=None):
        utils._check_type(stream_class, bt2.stream_class._StreamClass)

        if stream_class.assigns_automatic_stream_id:
            if id is not None:
                raise ValueError("id provided, but stream class assigns automatic stream ids")

            stream_ptr = native_bt.stream_create(stream_class._ptr, self._ptr)
        else:
            if id is None:
                raise ValueError("id not provided, but stream class does not assign automatic stream ids")

            utils._check_uint64(id)
            stream_ptr = native_bt.stream_create_with_id(stream_class._ptr, self._ptr, id)

        if stream_ptr is None:
            raise bt2.CreationError('cannot create stream object')

        stream = bt2.stream._Stream._create_from_ptr(stream_ptr)

        if name is not None:
            stream._name = name

        return stream

    def add_destruction_listener(self, listener):
        '''Add a listener to be called when the trace is destroyed.'''
        if not callable(listener):
            raise TypeError("'listener' parameter is not callable")

        fn = native_bt.py3_trace_add_destruction_listener
        listener_from_native = functools.partial(_trace_destruction_listener_from_native,
                                                 listener)

        listener_id = fn(self._ptr, listener_from_native)
        if listener_id is None:
            utils._raise_bt2_error('cannot add destruction listener to trace object')

        return bt2._ListenerHandle(listener_id, self)