split shared.py into multiple files; should resolve all circular reference import errors related to shared.py

modules/shared_items.py

@@ -1,3 +1,6 @@
+import sys
+
+from modules.shared_cmd_options import cmd_opts
 
 
 def realesrgan_models_names():
@@ -41,6 +44,28 @@ def refresh_unet_list():
     modules.sd_unet.list_unets()
 
 
+def list_checkpoint_tiles():
+    import modules.sd_models
+    return modules.sd_models.checkpoint_tiles()
+
+
+def refresh_checkpoints():
+    import modules.sd_models
+    return modules.sd_models.list_models()
+
+
+def list_samplers():
+    import modules.sd_samplers
+    return modules.sd_samplers.all_samplers
+
+
+def reload_hypernetworks():
+    from modules.hypernetworks import hypernetwork
+    from modules import shared
+
+    shared.hypernetworks = hypernetwork.list_hypernetworks(cmd_opts.hypernetwork_dir)
+
+
 ui_reorder_categories_builtin_items = [
     "inpaint",
     "sampler",
@@ -67,3 +92,27 @@ def ui_reorder_categories():
     yield from sections
 
     yield "scripts"
+
+
+class Shared(sys.modules[__name__].__class__):
+    """
+    this class is here to provide sd_model field as a property, so that it can be created and loaded on demand rather than
+    at program startup.
+    """
+
+    sd_model_val = None
+
+    @property
+    def sd_model(self):
+        import modules.sd_models
+
+        return modules.sd_models.model_data.get_sd_model()
+
+    @sd_model.setter
+    def sd_model(self, value):
+        import modules.sd_models
+
+        modules.sd_models.model_data.set_sd_model(value)
+
+
+sys.modules['modules.shared'].__class__ = Shared