rework sd1.5 and sdxl from scratch

backend/diffusion_engine/base.py

@@ -0,0 +1,60 @@
+import torch
+
+
+class ForgeObjects:
+    def __init__(self, unet, clip, vae, clipvision):
+        self.unet = unet
+        self.clip = clip
+        self.vae = vae
+        self.clipvision = clipvision
+
+    def shallow_copy(self):
+        return ForgeObjects(
+            self.unet,
+            self.clip,
+            self.vae,
+            self.clipvision
+        )
+
+
+class ForgeDiffusionEngine:
+    matched_guesses = []
+
+    def __init__(self, estimated_config, huggingface_components):
+        self.model_config = estimated_config
+        self.is_inpaint = estimated_config.inpaint_model()
+
+        self.forge_objects = None
+        self.forge_objects_original = None
+        self.forge_objects_after_applying_lora = None
+
+        self.current_lora_hash = str([])
+        self.tiling_enabled = False
+
+        # WebUI Dirty Legacy
+        self.cond_stage_key = 'txt'
+        self.is_sd3 = False
+        self.latent_channels = 4
+        self.is_sdxl = False
+        self.is_sdxl_inpaint = False
+        self.is_sd2 = False
+        self.is_sd1 = False
+        self.is_ssd = False
+
+    def set_clip_skip(self, clip_skip):
+        pass
+
+    def get_first_stage_encoding(self, x):
+        return x  # legacy code, do not change
+
+    def get_learned_conditioning(self, prompt: list[str]):
+        pass
+
+    def encode_first_stage(self, x):
+        pass
+
+    def decode_first_stage(self, x):
+        pass
+
+    def get_prompt_lengths_on_ui(self, prompt):
+        pass