| # Licensed under the Apache License, Version 2.0 (the "License"); |
| # you may not use this file except in compliance with the License. |
| # You may obtain a copy of the License at |
| # |
| # http://www.apache.org/licenses/LICENSE-2.0 |
| # |
| # Unless required by applicable law or agreed to in writing, software |
| # distributed under the License is distributed on an "AS IS" BASIS, |
| # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| # See the License for the specific language governing permissions and |
| # limitations under the License. |
| |
| from ...utils.openclose import OpenClose |
| from .exceptions import ReaderException, AlreadyReadException |
| |
| |
| class Reader(object): |
| """ |
| Base class for ARIA readers. |
| |
| Readers provide agnostic raw data by consuming :class:`aria.parser.loading.Loader` instances. |
| """ |
| |
| def __init__(self, context, location, loader): |
| self.context = context |
| self.location = location |
| self.loader = loader |
| |
| def load(self): |
| with OpenClose(self.loader) as loader: |
| if self.context is not None: |
| with self.context._locations: |
| for location in self.context._locations: |
| if location.is_equivalent(loader.location): |
| raise AlreadyReadException('already read: %s' % loader.location) |
| self.context._locations.append(loader.location) |
| |
| data = loader.load() |
| if data is None: |
| raise ReaderException('loader did not provide data: %s' % loader) |
| return data |
| |
| def read(self): |
| raise NotImplementedError |