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