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| author | Andrej Rode <mail@andrejro.de> | 2018-06-23 17:44:58 +0200 |
|---|---|---|
| committer | Andrej Rode <mail@andrejro.de> | 2018-06-23 17:44:58 +0200 |
| commit | 5e07e65fe9350a51cd45f8f21cfa6bf144e42e1c (patch) | |
| tree | b88dde44a0ba1f2ce1b382bbca02e80050f77a17 /grc/core/cache.py | |
| parent | 9f7e39ee5141791f93dbc1c842b1d1a49e33b068 (diff) | |
| parent | e82e337d0c74fa7ea5e8b8429de29bec43818552 (diff) | |
Merge branch 'python3_fix' into python3_merge
Diffstat (limited to 'grc/core/cache.py')
| -rw-r--r-- | grc/core/cache.py | 99 |
1 files changed, 99 insertions, 0 deletions
diff --git a/grc/core/cache.py b/grc/core/cache.py new file mode 100644 index 0000000000..f438d58bd9 --- /dev/null +++ b/grc/core/cache.py @@ -0,0 +1,99 @@ +# Copyright 2017 Free Software Foundation, Inc. +# This file is part of GNU Radio +# +# GNU Radio Companion is free software; you can redistribute it and/or +# modify it under the terms of the GNU General Public License +# as published by the Free Software Foundation; either version 2 +# of the License, or (at your option) any later version. +# +# GNU Radio Companion 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, write to the Free Software +# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA + +from __future__ import absolute_import, print_function + +from io import open +import json +import logging +import os + +import six + +from .io import yaml + +logger = logging.getLogger(__name__) + + +class Cache(object): + + def __init__(self, filename): + self.cache_file = filename + self.cache = {} + self.need_cache_write = True + self._accessed_items = set() + try: + os.makedirs(os.path.dirname(filename)) + except OSError: + pass + try: + self._converter_mtime = os.path.getmtime(filename) + except OSError: + self._converter_mtime = -1 + + def load(self): + try: + logger.debug("Loading block cache from: {}".format(self.cache_file)) + with open(self.cache_file, encoding='utf-8') as cache_file: + self.cache = json.load(cache_file) + self.need_cache_write = False + except (IOError, ValueError): + self.need_cache_write = True + + def get_or_load(self, filename): + self._accessed_items.add(filename) + if os.path.getmtime(filename) <= self._converter_mtime: + try: + return self.cache[filename] + except KeyError: + pass + + with open(filename, encoding='utf-8') as fp: + data = yaml.safe_load(fp) + self.cache[filename] = data + self.need_cache_write = True + return data + + def save(self): + if not self.need_cache_write: + return + + logger.info('Saving %d entries to json cache', len(self.cache)) + with open(self.cache_file, 'w', encoding='utf8') as cache_file: + json.dump(self.cache, cache_file) + + def prune(self): + for filename in (set(self.cache) - self._accessed_items): + del self.cache[filename] + + def __enter__(self): + self.load() + return self + + def __exit__(self, exc_type, exc_val, exc_tb): + self.save() + + +def byteify(data): + if isinstance(data, dict): + return {byteify(key): byteify(value) for key, value in six.iteritems(data)} + elif isinstance(data, list): + return [byteify(element) for element in data] + elif isinstance(data, six.text_type) and six.PY2: + return data.encode('utf-8') + else: + return data |