111 lines
4.1 KiB
Python
111 lines
4.1 KiB
Python
from typing import TYPE_CHECKING, Dict, List, Tuple, Any, Union, NamedTuple
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from typing import Optional, Callable, Iterator, Generator
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from .backref import VGroups
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from .model import ModelReader
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from .vobj import GroupBySource
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if TYPE_CHECKING:
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from lektor.db import Pad, Record
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from .config import Config
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from .model import FieldKeyPath
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class GroupByCallbackArgs(NamedTuple):
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record: 'Record'
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key: 'FieldKeyPath'
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field: Any # lektor model data-field value
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GroupingCallback = Callable[[GroupByCallbackArgs], Union[
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Iterator[Union[str, Tuple[str, Any]]],
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Generator[Union[str, Tuple[str, Any]], Optional[str], None],
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]]
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class Watcher:
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'''
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Callback is called with (Record, FieldKeyPath, field-value).
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Callback may yield one or more (group, extra-info) tuples.
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'''
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def __init__(self, config: 'Config') -> None:
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self.config = config
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self._root = self.config.root
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def grouping(self, flatten: bool = True) \
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-> Callable[[GroupingCallback], None]:
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'''
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Decorator to subscribe to attrib-elements.
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If flatten = False, dont explode FlowType.
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(record, field-key, field) -> (group, extra-info)
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'''
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def _decorator(fn: GroupingCallback) -> None:
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self.flatten = flatten
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self.callback = fn
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return _decorator
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def initialize(self, pad: 'Pad') -> None:
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''' Reset internal state. You must initialize before each build! '''
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assert callable(self.callback), 'No grouping callback provided.'
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self._model_reader = ModelReader(pad.db, self.config.key, self.flatten)
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self._root_record = {} # type: Dict[str, Record]
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self._state = {} # type: Dict[str, Dict[str, GroupBySource]]
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for alt in pad.config.iter_alternatives():
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self._root_record[alt] = pad.get(self._root, alt=alt)
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self._state[alt] = {}
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def should_process(self, node: 'Record') -> bool:
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''' Check if record path is being watched. '''
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return node['_path'].startswith(self._root)
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def process(self, record: 'Record') -> None:
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'''
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Will iterate over all record fields and call the callback method.
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Each record is guaranteed to be processed only once.
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'''
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for key, field in self._model_reader.read(record):
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_gen = self.callback(GroupByCallbackArgs(record, key, field))
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try:
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group = next(_gen)
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while True:
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if not isinstance(group, str):
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raise TypeError(f'Unsupported groupby yield: {group}')
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slug = self._persist(record, key, group)
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# return slugified group key and continue iteration
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if isinstance(_gen, Generator) and not _gen.gi_yieldfrom:
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group = _gen.send(slug)
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else:
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group = next(_gen)
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except StopIteration:
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del _gen
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def _persist(self, record: 'Record', key: 'FieldKeyPath', group: str) \
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-> str:
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''' Update internal state. Return slugified string. '''
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alt = record.alt
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slug = self.config.slugify(group)
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if slug not in self._state[alt]:
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src = GroupBySource(self._root_record[alt], slug)
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self._state[alt][slug] = src
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else:
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src = self._state[alt][slug]
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src.append_child(record, group)
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# reverse reference
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VGroups.of(record).add(key, src)
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return slug
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def iter_sources(self, root: 'Record') -> Iterator[GroupBySource]:
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''' Prepare and yield GroupBySource elements. '''
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for vobj_list in self._state.values():
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for vobj in vobj_list.values():
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yield vobj.finalize(self.config)
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# cleanup. remove this code if you'd like to iter twice
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del self._model_reader
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del self._root_record
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del self._state
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def __repr__(self) -> str:
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return '<GroupByWatcher key="{}" enabled={} callback={}>'.format(
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self.config.key, self.config.enabled, self.callback)
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