[Conversion] Support convert diffusers to safetensors (#1996)

fix: support diffusers to safetensors

scripts/convert_diffusers_to_original_stable_diffusion.py

@@ -8,6 +8,8 @@ import re
 
 import torch
 
+from safetensors.torch import save_file
+
 
 # =================#
 # UNet Conversion #
@@ -266,6 +268,9 @@ if __name__ == "__main__":
     parser.add_argument("--model_path", default=None, type=str, required=True, help="Path to the model to convert.")
     parser.add_argument("--checkpoint_path", default=None, type=str, required=True, help="Path to the output model.")
     parser.add_argument("--half", action="store_true", help="Save weights in half precision.")
+    parser.add_argument(
+        "--use_safetensors", action="store_true", help="Save weights use safetensors, default is ckpt."
+    )
 
     args = parser.parse_args()
 
@@ -306,5 +311,9 @@ if __name__ == "__main__":
     state_dict = {**unet_state_dict, **vae_state_dict, **text_enc_dict}
     if args.half:
         state_dict = {k: v.half() for k, v in state_dict.items()}
-    state_dict = {"state_dict": state_dict}
-    torch.save(state_dict, args.checkpoint_path)
+
+    if args.use_safetensors:
+        save_file(state_dict, args.checkpoint_path)
+    else:
+        state_dict = {"state_dict": state_dict}
+        torch.save(state_dict, args.checkpoint_path)