chore: import upstream snapshot with attribution

invokeai/backend/stable_diffusion/extensions/base.py

@@ -0,0 +1,72 @@
+from __future__ import annotations
+
+from contextlib import contextmanager
+from dataclasses import dataclass
+from typing import TYPE_CHECKING, Callable, Dict, List
+
+from diffusers import UNet2DConditionModel
+
+if TYPE_CHECKING:
+    from invokeai.backend.stable_diffusion.denoise_context import DenoiseContext
+    from invokeai.backend.stable_diffusion.extension_callback_type import ExtensionCallbackType
+    from invokeai.backend.util.original_weights_storage import OriginalWeightsStorage
+
+
+@dataclass
+class CallbackMetadata:
+    callback_type: ExtensionCallbackType
+    order: int
+
+
+@dataclass
+class CallbackFunctionWithMetadata:
+    metadata: CallbackMetadata
+    function: Callable[[DenoiseContext], None]
+
+
+def callback(callback_type: ExtensionCallbackType, order: int = 0):
+    def _decorator(function):
+        function._ext_metadata = CallbackMetadata(
+            callback_type=callback_type,
+            order=order,
+        )
+        return function
+
+    return _decorator
+
+
+class ExtensionBase:
+    def __init__(self):
+        self._callbacks: Dict[ExtensionCallbackType, List[CallbackFunctionWithMetadata]] = {}
+
+        # Register all of the callback methods for this instance.
+        for func_name in dir(self):
+            func = getattr(self, func_name)
+            metadata = getattr(func, "_ext_metadata", None)
+            if metadata is not None and isinstance(metadata, CallbackMetadata):
+                if metadata.callback_type not in self._callbacks:
+                    self._callbacks[metadata.callback_type] = []
+                self._callbacks[metadata.callback_type].append(CallbackFunctionWithMetadata(metadata, func))
+
+    def get_callbacks(self):
+        return self._callbacks
+
+    @contextmanager
+    def patch_extension(self, ctx: DenoiseContext):
+        yield None
+
+    @contextmanager
+    def patch_unet(self, unet: UNet2DConditionModel, original_weights: OriginalWeightsStorage):
+        """A context manager for applying patches to the UNet model. The context manager's lifetime spans the entire
+        diffusion process. Weight unpatching is handled upstream, and is achieved by saving unchanged weights by
+        `original_weights.save` function. Note that this enables some performance optimization by avoiding redundant
+        operations. All other patches (e.g. changes to tensor shapes, function monkey-patches, etc.) should be unpatched
+        by this context manager.
+
+        Args:
+            unet (UNet2DConditionModel): The UNet model on execution device to patch.
+            original_weights (OriginalWeightsStorage): A storage with copy of the model's original weights in CPU, for
+                unpatching purposes. Extension should save tensor which being modified in this storage, also extensions
+                can access original weights values.
+        """
+        yield