# Source code for spinn_utilities.abstract_context_manager

# Copyright (c) 2017 The University of Manchester
#
# This program is free software: you can redistribute it and/or modify
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

from .abstract_base import AbstractBase, abstractmethod

[docs]class AbstractContextManager(object, metaclass=AbstractBase):
""" Closeable class that supports being used as a simple context manager.
"""

__slots__ = []

[docs]    @abstractmethod
def close(self):
""" How to actually close the underlying resources.
"""

def _context_entered(self):
""" Called when the context is entered. The result is ignored.
"""

def _context_exception_occurred(self, exc_type, exc_val, exc_tb):
""" Called when an exception occurs during the with context, *after*\
the context has been closed.

:param type exc_type:
:param object exc_val:
:param traceback exc_tb:
"""

def __enter__(self):
self._context_entered()
return self

def __exit__(self, exc_type, exc_val, exc_tb):
self.close()
if exc_type:
self._context_exception_occurred(exc_type, exc_val, exc_tb)
return False