87 lines
3.1 KiB
Python
87 lines
3.1 KiB
Python
# vi: ts=4 expandtab
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#
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# Copyright (C) 2012 Yahoo! Inc.
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#
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# Author: Joshua Harlow <harlowja@yahoo-inc.com>
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#
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# This program is free software: you can redistribute it and/or modify
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# it under the terms of the GNU General Public License version 3, as
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# published by the Free Software Foundation.
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#
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with this program. If not, see <http://www.gnu.org/licenses/>.
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DEF_MERGE_TYPE = 'no_replace'
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MERGE_TYPES = ('replace', DEF_MERGE_TYPE,)
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def _has_any(what, *keys):
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for k in keys:
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if k in what:
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return True
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return False
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class Merger(object):
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def __init__(self, merger, opts):
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self._merger = merger
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# Affects merging behavior...
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self._method = DEF_MERGE_TYPE
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for m in MERGE_TYPES:
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if m in opts:
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self._method = m
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break
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# Affect how recursive merging is done on other primitives.
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self._recurse_str = 'recurse_str' in opts
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self._recurse_array = _has_any(opts, 'recurse_array', 'recurse_list')
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self._allow_delete = 'allow_delete' in opts
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# Backwards compat require this to be on.
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self._recurse_dict = True
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def __str__(self):
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s = ('DictMerger: (method=%s,recurse_str=%s,'
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'recurse_dict=%s,recurse_array=%s,allow_delete=%s)')
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s = s % (self._method, self._recurse_str,
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self._recurse_dict, self._recurse_array, self._allow_delete)
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return s
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def _do_dict_replace(self, value, merge_with, do_replace):
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def merge_same_key(old_v, new_v):
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if do_replace:
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return new_v
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if isinstance(new_v, (list, tuple)) and self._recurse_array:
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return self._merger.merge(old_v, new_v)
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if isinstance(new_v, (basestring)) and self._recurse_str:
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return self._merger.merge(old_v, new_v)
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if isinstance(new_v, (dict)) and self._recurse_dict:
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return self._merger.merge(old_v, new_v)
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# Otherwise leave it be...
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return old_v
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for (k, v) in merge_with.items():
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if k in value:
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if v is None and self._allow_delete:
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value.pop(k)
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else:
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value[k] = merge_same_key(value[k], v)
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else:
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value[k] = v
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return value
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def _on_dict(self, value, merge_with):
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if not isinstance(merge_with, (dict)):
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return value
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if self._method == 'replace':
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merged = self._do_dict_replace(dict(value), merge_with, True)
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elif self._method == 'no_replace':
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merged = self._do_dict_replace(dict(value), merge_with, False)
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else:
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raise NotImplementedError("Unknown merge type %s" % (self._method))
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return merged
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