64 lines
1.8 KiB
Python
64 lines
1.8 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 ..pyotherside_events import ModelItemFieldChanged
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from ..utils import serialize_value_for_qml
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if TYPE_CHECKING:
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from .model import Model
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class ModelItem:
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"""Base class for items stored inside a `Model`.
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This class must be subclassed and not used directly.
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All subclasses must be dataclasses.
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Subclasses are also expected to implement `__lt__()`,
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to provide support for comparisons with the `<`, `>`, `<=`, `=>` operators
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and thus allow a `Model` to sort its `ModelItem`s.
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"""
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def __new__(cls, *_args, **_kwargs) -> "ModelItem":
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cls.parent_model: Optional[Model] = None
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return super().__new__(cls)
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def __setattr__(self, name: str, value) -> None:
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"""If this item is in a `Model`, alert it of attribute changes."""
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if name == "parent_model" or self.parent_model is None:
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super().__setattr__(name, value)
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return
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if getattr(self, name) == value:
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return
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super().__setattr__(name, value)
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old_index = self.parent_model._sorted_data.index(self)
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self.parent_model._sorted_data.sort()
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new_index = self.parent_model._sorted_data.index(self)
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ModelItemFieldChanged(
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self.parent_model.sync_id, old_index, new_index, name, value,
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)
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def __delattr__(self, name: str) -> None:
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raise NotImplementedError()
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@property
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def serialized(self) -> Dict[str, Any]:
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"""Return this item as a dict ready to be passed to QML."""
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return {
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name: serialize_value_for_qml(getattr(self, name), json_lists=True)
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for name in dir(self)
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if not (
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name.startswith("_") or name in ("parent_model", "serialized")
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)
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}
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