73 lines
2.2 KiB
Python
73 lines
2.2 KiB
Python
# SPDX-License-Identifier: LGPL-3.0-or-later
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from typing import TYPE_CHECKING, Any, Dict, Optional
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from . import SyncId
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from .model import Model
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if TYPE_CHECKING:
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from .model_item import ModelItem
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class ModelProxy(Model):
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"""Proxies data from one or more `Model` objects."""
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def __init__(self, sync_id: SyncId) -> None:
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super().__init__(sync_id)
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self.take_items_ownership = False
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Model.proxies[sync_id] = self
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for sync_id, model in Model.instances.items():
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if sync_id != self.sync_id and self.accept_source(model):
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for key, item in model.items():
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self.source_item_set(model, key, item)
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def accept_source(self, source: Model) -> bool:
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"""Return whether passed `Model` should be proxied by this proxy."""
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return True
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def convert_item(self, item: "ModelItem") -> "ModelItem":
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"""Take a source `ModelItem`, return an appropriate one for proxy.
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By default, this returns the passed item unchanged.
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Due to QML `ListModel` restrictions, if multiple source models
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containing different subclasses of `ModelItem` are proxied,
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they should be converted to a same `ModelItem`
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subclass by overriding this function.
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"""
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return item
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def source_item_set(
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self,
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source: Model,
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key,
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value: "ModelItem",
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_changed_fields: Optional[Dict[str, Any]] = None,
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) -> None:
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"""Called when a source model item is added or changed."""
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if self.accept_source(source):
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value = self.convert_item(value)
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self.__setitem__((source.sync_id, key), value, _changed_fields)
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def source_item_deleted(self, source: Model, key) -> None:
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"""Called when a source model item is removed."""
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if self.accept_source(source):
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del self[source.sync_id, key]
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def source_cleared(self, source: Model) -> None:
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"""Called when a source model is cleared."""
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if self.accept_source(source):
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with self.batch_remove():
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for source_sync_id, key in self.copy():
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if source_sync_id == source.sync_id:
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del self[source_sync_id, key]
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