Holy $hit.

Yep.

Fix gfpgan_model_arch requirement(s).
Add Upscaler base class, move from images.
Add a lot of methods to Upscaler.
Re-work all the child upscalers to be proper classes.
Add BSRGAN scaler.
Add ldsr_model_arch class, removing the dependency for another repo that just uses regular latent-diffusion stuff.
Add one universal method that will always find and load new upscaler models without having to add new "setup_model" calls. Still need to add command line params, but that could probably be automated.
Add a "self.scale" property to all Upscalers so the scalers themselves can do "things" in response to the requested upscaling size.
Ensure LDSR doesn't get stuck in a longer loop of "upscale/downscale/upscale" as we try to reach the target upscale size.
Add typehints for IDE sanity.
PEP-8 improvements.
Moar.

modules/ldsr_model.py

@@ -1,74 +1,45 @@
 import os
 import sys
 import traceback
-from collections import namedtuple
 
-from modules import shared, images, modelloader, paths
+from basicsr.utils.download_util import load_file_from_url
+
+from modules.upscaler import Upscaler, UpscalerData
+from modules.ldsr_model_arch import LDSR
+from modules import shared
 from modules.paths import models_path
 
-model_dir = "LDSR"
-model_path = os.path.join(models_path, model_dir)
-cmd_path = None
-model_url = "https://heibox.uni-heidelberg.de/f/578df07c8fc04ffbadf3/?dl=1"
-yaml_url = "https://heibox.uni-heidelberg.de/f/31a76b13ea27482981b4/?dl=1"
 
-LDSRModelInfo = namedtuple("LDSRModelInfo", ["name", "location", "model", "netscale"])
-
-ldsr_models = []
-have_ldsr = False
-LDSR_obj = None
-
-
-class UpscalerLDSR(images.Upscaler):
-    def __init__(self, steps):
-        self.steps = steps
+class UpscalerLDSR(Upscaler):
+    def __init__(self, user_path):
         self.name = "LDSR"
+        self.model_path = os.path.join(models_path, self.name)
+        self.user_path = user_path
+        self.model_url = "https://heibox.uni-heidelberg.de/f/578df07c8fc04ffbadf3/?dl=1"
+        self.yaml_url = "https://heibox.uni-heidelberg.de/f/31a76b13ea27482981b4/?dl=1"
+        super().__init__()
+        scaler_data = UpscalerData("LDSR", None, self)
+        self.scalers = [scaler_data]
 
-    def do_upscale(self, img):
-        return upscale_with_ldsr(img)
+    def load_model(self, path: str):
+        model = load_file_from_url(url=self.model_url, model_dir=self.model_path,
+                                   file_name="model.pth", progress=True)
+        yaml = load_file_from_url(url=self.model_url, model_dir=self.model_path,
+                                  file_name="project.yaml", progress=True)
 
+        try:
+            return LDSR(model, yaml)
 
-def setup_model(dirname):
-    global cmd_path
-    global model_path
-    if not os.path.exists(model_path):
-        os.makedirs(model_path)
-    cmd_path = dirname
-    shared.sd_upscalers.append(UpscalerLDSR(100))
+        except Exception:
+            print("Error importing LDSR:", file=sys.stderr)
+            print(traceback.format_exc(), file=sys.stderr)
+        return None
 
-
-def prepare_ldsr():
-    path = paths.paths.get("LDSR", None)
-    if path is None:
-        return
-    global have_ldsr
-    global LDSR_obj
-    try:
-        from LDSR import LDSR
-        model_files = modelloader.load_models(model_path, model_url, cmd_path, dl_name="model.ckpt", ext_filter=[".ckpt"])
-        yaml_files = modelloader.load_models(model_path, yaml_url, cmd_path, dl_name="project.yaml", ext_filter=[".yaml"])
-        if len(model_files) != 0 and len(yaml_files) != 0:
-            model_file = model_files[0]
-            yaml_file = yaml_files[0]
-            have_ldsr = True
-            LDSR_obj = LDSR(model_file, yaml_file)
-        else:
-            return
-
-    except Exception:
-        print("Error importing LDSR:", file=sys.stderr)
-        print(traceback.format_exc(), file=sys.stderr)
-        have_ldsr = False
-
-
-def upscale_with_ldsr(image):
-    prepare_ldsr()
-    if not have_ldsr or LDSR_obj is None:
-        return image
-
-    ddim_steps = shared.opts.ldsr_steps
-    pre_scale = shared.opts.ldsr_pre_down
-    post_scale = shared.opts.ldsr_post_down
-
-    image = LDSR_obj.super_resolution(image, ddim_steps, pre_scale, post_scale)
-    return image
+    def do_upscale(self, img, path):
+        ldsr = self.load_model(path)
+        if ldsr is None:
+            print("NO LDSR!")
+            return img
+        ddim_steps = shared.opts.ldsr_steps
+        pre_scale = shared.opts.ldsr_pre_down
+        return ldsr.super_resolution(img, ddim_steps, self.scale)