[`Refactor`] `StableDiffusionReferencePipeline` inheriting from `DiffusionPipeline` (#7071)

Refactor StableDiffusionReferencePipeline to inherit from DiffusionPipeline rather than StableDiffusionPipeline

examples/community/stable_diffusion_reference.py

 # Inspired by: https://github.com/Mikubill/sd-webui-controlnet/discussions/1236 and https://github.com/Mikubill/sd-webui-controlnet/discussions/1280
+import inspect
 from typing import Any, Callable, Dict, List, Optional, Tuple, Union
 
 import numpy as np
 import PIL.Image
 import torch
+from packaging import version
+from transformers import CLIPImageProcessor, CLIPTextModel, CLIPTokenizer
 
-from diffusers import StableDiffusionPipeline
+from diffusers import AutoencoderKL, DiffusionPipeline, UNet2DConditionModel
+from diffusers.configuration_utils import FrozenDict, deprecate
+from diffusers.image_processor import VaeImageProcessor
+from diffusers.loaders import FromSingleFileMixin, IPAdapterMixin, LoraLoaderMixin, TextualInversionLoaderMixin
 from diffusers.models.attention import BasicTransformerBlock
+from diffusers.models.lora import adjust_lora_scale_text_encoder
 from diffusers.models.unets.unet_2d_blocks import CrossAttnDownBlock2D, CrossAttnUpBlock2D, DownBlock2D, UpBlock2D
 from diffusers.pipelines.stable_diffusion import StableDiffusionPipelineOutput
 from diffusers.pipelines.stable_diffusion.pipeline_stable_diffusion import rescale_noise_cfg
-from diffusers.utils import PIL_INTERPOLATION, logging
+from diffusers.pipelines.stable_diffusion.safety_checker import StableDiffusionSafetyChecker
+from diffusers.schedulers import KarrasDiffusionSchedulers
+from diffusers.utils import (
+    PIL_INTERPOLATION,
+    USE_PEFT_BACKEND,
+    logging,
+    scale_lora_layers,
+    unscale_lora_layers,
+)
 from diffusers.utils.torch_utils import randn_tensor
 
 
@@ -45,14 +60,182 @@ EXAMPLE_DOC_STRING = """
 
 
 def torch_dfs(model: torch.nn.Module):
+    r"""
+    Performs a depth-first search on the given PyTorch model and returns a list of all its child modules.
+
+    Args:
+        model (torch.nn.Module): The PyTorch model to perform the depth-first search on.
+
+    Returns:
+        list: A list of all child modules of the given model.
+    """
     result = [model]
     for child in model.children():
         result += torch_dfs(child)
     return result
 
 
-class StableDiffusionReferencePipeline(StableDiffusionPipeline):
-    def _default_height_width(self, height, width, image):
+class StableDiffusionReferencePipeline(
+    DiffusionPipeline, TextualInversionLoaderMixin, LoraLoaderMixin, IPAdapterMixin, FromSingleFileMixin
+):
+    r""" "
+    Pipeline for Stable Diffusion Reference.
+
+    This model inherits from [`DiffusionPipeline`]. Check the superclass documentation for the generic methods
+    implemented for all pipelines (downloading, saving, running on a particular device, etc.).
+
+    The pipeline also inherits the following loading methods:
+    - [`~loaders.TextualInversionLoaderMixin.load_textual_inversion`] for loading textual inversion embeddings
+    - [`~loaders.LoraLoaderMixin.load_lora_weights`] for loading LoRA weights
+    - [`~loaders.LoraLoaderMixin.save_lora_weights`] for saving LoRA weights
+    - [`~loaders.FromSingleFileMixin.from_single_file`] for loading `.ckpt` files
+    - [`~loaders.IPAdapterMixin.load_ip_adapter`] for loading IP Adapters
+
+    Args:
+        vae ([`AutoencoderKL`]):
+            Variational Auto-Encoder (VAE) Model to encode and decode images to and from latent representations.
+        text_encoder ([`CLIPTextModel`]):
+            Frozen text-encoder. Stable Diffusion uses the text portion of
+            [CLIP](https://huggingface.co/docs/transformers/model_doc/clip#transformers.CLIPTextModel), specifically
+            the [clip-vit-large-patch14](https://huggingface.co/openai/clip-vit-large-patch14) variant.
+        tokenizer (`CLIPTokenizer`):
+            Tokenizer of class
+            [CLIPTokenizer](https://huggingface.co/docs/transformers/v4.21.0/en/model_doc/clip#transformers.CLIPTokenizer).
+        unet ([`UNet2DConditionModel`]): Conditional U-Net architecture to denoise the encoded image latents.
+        scheduler ([`SchedulerMixin`]):
+            A scheduler to be used in combination with `unet` to denoise the encoded image latents. Can be one of
+            [`DDIMScheduler`], [`LMSDiscreteScheduler`], or [`PNDMScheduler`].
+        safety_checker ([`StableDiffusionSafetyChecker`]):
+            Classification module that estimates whether generated images could be considered offensive or harmful.
+            Please, refer to the [model card](https://huggingface.co/runwayml/stable-diffusion-v1-5) for details.
+        feature_extractor ([`CLIPImageProcessor`]):
+            Model that extracts features from generated images to be used as inputs for the `safety_checker`.
+    """
+
+    _optional_components = ["safety_checker", "feature_extractor"]
+
+    def __init__(
+        self,
+        vae: AutoencoderKL,
+        text_encoder: CLIPTextModel,
+        tokenizer: CLIPTokenizer,
+        unet: UNet2DConditionModel,
+        scheduler: KarrasDiffusionSchedulers,
+        safety_checker: StableDiffusionSafetyChecker,
+        feature_extractor: CLIPImageProcessor,
+        requires_safety_checker: bool = True,
+    ):
+        super().__init__()
+
+        if hasattr(scheduler.config, "steps_offset") and scheduler.config.steps_offset != 1:
+            deprecation_message = (
+                f"The configuration file of this scheduler: {scheduler} is outdated. `steps_offset`"
+                f" should be set to 1 instead of {scheduler.config.steps_offset}. Please make sure "
+                "to update the config accordingly as leaving `steps_offset` might led to incorrect results"
+                " in future versions. If you have downloaded this checkpoint from the Hugging Face Hub,"
+                " it would be very nice if you could open a Pull request for the `scheduler/scheduler_config.json`"
+                " file"
+            )
+            deprecate("steps_offset!=1", "1.0.0", deprecation_message, standard_warn=False)
+            new_config = dict(scheduler.config)
+            new_config["steps_offset"] = 1
+            scheduler._internal_dict = FrozenDict(new_config)
+
+        if hasattr(scheduler.config, "skip_prk_steps") and scheduler.config.skip_prk_steps is False:
+            deprecation_message = (
+                f"The configuration file of this scheduler: {scheduler} has not set the configuration"
+                " `skip_prk_steps`. `skip_prk_steps` should be set to True in the configuration file. Please make"
+                " sure to update the config accordingly as not setting `skip_prk_steps` in the config might lead to"
+                " incorrect results in future versions. If you have downloaded this checkpoint from the Hugging Face"
+                " Hub, it would be very nice if you could open a Pull request for the"
+                " `scheduler/scheduler_config.json` file"
+            )
+            deprecate(
+                "skip_prk_steps not set",
+                "1.0.0",
+                deprecation_message,
+                standard_warn=False,
+            )
+            new_config = dict(scheduler.config)
+            new_config["skip_prk_steps"] = True
+            scheduler._internal_dict = FrozenDict(new_config)
+
+        if safety_checker is None and requires_safety_checker:
+            logger.warning(
+                f"You have disabled the safety checker for {self.__class__} by passing `safety_checker=None`. Ensure"
+                " that you abide to the conditions of the Stable Diffusion license and do not expose unfiltered"
+                " results in services or applications open to the public. Both the diffusers team and Hugging Face"
+                " strongly recommend to keep the safety filter enabled in all public facing circumstances, disabling"
+                " it only for use-cases that involve analyzing network behavior or auditing its results. For more"
+                " information, please have a look at https://github.com/huggingface/diffusers/pull/254 ."
+            )
+
+        if safety_checker is not None and feature_extractor is None:
+            raise ValueError(
+                "Make sure to define a feature extractor when loading {self.__class__} if you want to use the safety"
+                " checker. If you do not want to use the safety checker, you can pass `'safety_checker=None'` instead."
+            )
+
+        is_unet_version_less_0_9_0 = hasattr(unet.config, "_diffusers_version") and version.parse(
+            version.parse(unet.config._diffusers_version).base_version
+        ) < version.parse("0.9.0.dev0")
+        is_unet_sample_size_less_64 = hasattr(unet.config, "sample_size") and unet.config.sample_size < 64
+        if is_unet_version_less_0_9_0 and is_unet_sample_size_less_64:
+            deprecation_message = (
+                "The configuration file of the unet has set the default `sample_size` to smaller than"
+                " 64 which seems highly unlikely .If you're checkpoint is a fine-tuned version of any of the"
+                " following: \n- CompVis/stable-diffusion-v1-4 \n- CompVis/stable-diffusion-v1-3 \n-"
+                " CompVis/stable-diffusion-v1-2 \n- CompVis/stable-diffusion-v1-1 \n- runwayml/stable-diffusion-v1-5"
+                " \n- runwayml/stable-diffusion-inpainting \n you should change 'sample_size' to 64 in the"
+                " configuration file. Please make sure to update the config accordingly as leaving `sample_size=32`"
+                " in the config might lead to incorrect results in future versions. If you have downloaded this"
+                " checkpoint from the Hugging Face Hub, it would be very nice if you could open a Pull request for"
+                " the `unet/config.json` file"
+            )
+            deprecate("sample_size<64", "1.0.0", deprecation_message, standard_warn=False)
+            new_config = dict(unet.config)
+            new_config["sample_size"] = 64
+            unet._internal_dict = FrozenDict(new_config)
+        # Check shapes, assume num_channels_latents == 4, num_channels_mask == 1, num_channels_masked == 4
+        if unet.config.in_channels != 4:
+            logger.warning(
+                f"You have loaded a UNet with {unet.config.in_channels} input channels, whereas by default,"
+                f" {self.__class__} assumes that `pipeline.unet` has 4 input channels: 4 for `num_channels_latents`,"
+                ". If you did not intend to modify"
+                " this behavior, please check whether you have loaded the right checkpoint."
+            )
+
+        self.register_modules(
+            vae=vae,
+            text_encoder=text_encoder,
+            tokenizer=tokenizer,
+            unet=unet,
+            scheduler=scheduler,
+            safety_checker=safety_checker,
+            feature_extractor=feature_extractor,
+        )
+        self.vae_scale_factor = 2 ** (len(self.vae.config.block_out_channels) - 1)
+        self.image_processor = VaeImageProcessor(vae_scale_factor=self.vae_scale_factor)
+        self.register_to_config(requires_safety_checker=requires_safety_checker)
+
+    def _default_height_width(
+        self,
+        height: Optional[int],
+        width: Optional[int],
+        image: Union[PIL.Image.Image, torch.Tensor, List[PIL.Image.Image]],
+    ) -> Tuple[int, int]:
+        r"""
+        Calculate the default height and width for the given image.
+
+        Args:
+            height (int or None): The desired height of the image. If None, the height will be determined based on the input image.
+            width (int or None): The desired width of the image. If None, the width will be determined based on the input image.
+            image (PIL.Image.Image or torch.Tensor or list[PIL.Image.Image]): The input image or a list of images.
+
+        Returns:
+            Tuple[int, int]: A tuple containing the calculated height and width.
+
+        """
         # NOTE: It is possible that a list of images have different
         # dimensions for each image, so just checking the first image
         # is not _exactly_ correct, but it is simple.
@@ -77,18 +260,430 @@ class StableDiffusionReferencePipeline(StableDiffusionPipeline):
 
         return height, width
 
-    def prepare_image(
+    # Copied from diffusers.pipelines.stable_diffusion.pipeline_stable_diffusion.StableDiffusionPipeline.check_inputs
+    def check_inputs(
         self,
-        image,
-        width,
-        height,
-        batch_size,
-        num_images_per_prompt,
-        device,
-        dtype,
-        do_classifier_free_guidance=False,
-        guess_mode=False,
+        prompt: Optional[Union[str, List[str]]],
+        height: int,
+        width: int,
+        callback_steps: Optional[int],
+        negative_prompt: Optional[str] = None,
+        prompt_embeds: Optional[torch.FloatTensor] = None,
+        negative_prompt_embeds: Optional[torch.FloatTensor] = None,
+        ip_adapter_image: Optional[torch.Tensor] = None,
+        ip_adapter_image_embeds: Optional[torch.FloatTensor] = None,
+        callback_on_step_end_tensor_inputs: Optional[List[str]] = None,
+    ) -> None:
+        """
+        Check the validity of the input arguments for the diffusion model.
+
+        Args:
+            prompt (Optional[Union[str, List[str]]]): The prompt text or list of prompt texts.
+            height (int): The height of the input image.
+            width (int): The width of the input image.
+            callback_steps (Optional[int]): The number of steps to perform the callback on.
+            negative_prompt (Optional[str]): The negative prompt text.
+            prompt_embeds (Optional[torch.FloatTensor]): The prompt embeddings.
+            negative_prompt_embeds (Optional[torch.FloatTensor]): The negative prompt embeddings.
+            ip_adapter_image (Optional[torch.Tensor]): The input adapter image.
+            ip_adapter_image_embeds (Optional[torch.FloatTensor]): The input adapter image embeddings.
+            callback_on_step_end_tensor_inputs (Optional[List[str]]): The list of tensor inputs to perform the callback on.
+
+        Raises:
+            ValueError: If `height` or `width` is not divisible by 8.
+            ValueError: If `callback_steps` is not a positive integer.
+            ValueError: If `callback_on_step_end_tensor_inputs` contains invalid tensor inputs.
+            ValueError: If both `prompt` and `prompt_embeds` are provided.
+            ValueError: If neither `prompt` nor `prompt_embeds` are provided.
+            ValueError: If `prompt` is not of type `str` or `list`.
+            ValueError: If both `negative_prompt` and `negative_prompt_embeds` are provided.
+            ValueError: If both `prompt_embeds` and `negative_prompt_embeds` are provided and have different shapes.
+            ValueError: If both `ip_adapter_image` and `ip_adapter_image_embeds` are provided.
+
+        Returns:
+            None
+        """
+        if height % 8 != 0 or width % 8 != 0:
+            raise ValueError(f"`height` and `width` have to be divisible by 8 but are {height} and {width}.")
+
+        if callback_steps is not None and (not isinstance(callback_steps, int) or callback_steps <= 0):
+            raise ValueError(
+                f"`callback_steps` has to be a positive integer but is {callback_steps} of type"
+                f" {type(callback_steps)}."
+            )
+        if callback_on_step_end_tensor_inputs is not None and not all(
+            k in self._callback_tensor_inputs for k in callback_on_step_end_tensor_inputs
+        ):
+            raise ValueError(
+                f"`callback_on_step_end_tensor_inputs` has to be in {self._callback_tensor_inputs}, but found {[k for k in callback_on_step_end_tensor_inputs if k not in self._callback_tensor_inputs]}"
+            )
+
+        if prompt is not None and prompt_embeds is not None:
+            raise ValueError(
+                f"Cannot forward both `prompt`: {prompt} and `prompt_embeds`: {prompt_embeds}. Please make sure to"
+                " only forward one of the two."
+            )
+        elif prompt is None and prompt_embeds is None:
+            raise ValueError(
+                "Provide either `prompt` or `prompt_embeds`. Cannot leave both `prompt` and `prompt_embeds` undefined."
+            )
+        elif prompt is not None and (not isinstance(prompt, str) and not isinstance(prompt, list)):
+            raise ValueError(f"`prompt` has to be of type `str` or `list` but is {type(prompt)}")
+
+        if negative_prompt is not None and negative_prompt_embeds is not None:
+            raise ValueError(
+                f"Cannot forward both `negative_prompt`: {negative_prompt} and `negative_prompt_embeds`:"
+                f" {negative_prompt_embeds}. Please make sure to only forward one of the two."
+            )
+
+        if prompt_embeds is not None and negative_prompt_embeds is not None:
+            if prompt_embeds.shape != negative_prompt_embeds.shape:
+                raise ValueError(
+                    "`prompt_embeds` and `negative_prompt_embeds` must have the same shape when passed directly, but"
+                    f" got: `prompt_embeds` {prompt_embeds.shape} != `negative_prompt_embeds`"
+                    f" {negative_prompt_embeds.shape}."
+                )
+
+        if ip_adapter_image is not None and ip_adapter_image_embeds is not None:
+            raise ValueError(
+                "Provide either `ip_adapter_image` or `ip_adapter_image_embeds`. Cannot leave both `ip_adapter_image` and `ip_adapter_image_embeds` defined."
+            )
+
+    # Copied from diffusers.pipelines.stable_diffusion.pipeline_stable_diffusion.StableDiffusionPipeline._encode_prompt
+    def _encode_prompt(
+        self,
+        prompt: Union[str, List[str]],
+        device: torch.device,
+        num_images_per_prompt: int,
+        do_classifier_free_guidance: bool,
+        negative_prompt: Optional[Union[str, List[str]]] = None,
+        prompt_embeds: Optional[torch.FloatTensor] = None,
+        negative_prompt_embeds: Optional[torch.FloatTensor] = None,
+        lora_scale: Optional[float] = None,
+        **kwargs,
+    ) -> torch.FloatTensor:
+        r"""
+        Encodes the prompt into embeddings.
+
+        Args:
+            prompt (Union[str, List[str]]): The prompt text or a list of prompt texts.
+            device (torch.device): The device to use for encoding.
+            num_images_per_prompt (int): The number of images per prompt.
+            do_classifier_free_guidance (bool): Whether to use classifier-free guidance.
+            negative_prompt (Optional[Union[str, List[str]]], optional): The negative prompt text or a list of negative prompt texts. Defaults to None.
+            prompt_embeds (Optional[torch.FloatTensor], optional): The prompt embeddings. Defaults to None.
+            negative_prompt_embeds (Optional[torch.FloatTensor], optional): The negative prompt embeddings. Defaults to None.
+            lora_scale (Optional[float], optional): The LoRA scale. Defaults to None.
+            **kwargs: Additional keyword arguments.
+
+        Returns:
+            torch.FloatTensor: The encoded prompt embeddings.
+        """
+        deprecation_message = "`_encode_prompt()` is deprecated and it will be removed in a future version. Use `encode_prompt()` instead. Also, be aware that the output format changed from a concatenated tensor to a tuple."
+        deprecate("_encode_prompt()", "1.0.0", deprecation_message, standard_warn=False)
+
+        prompt_embeds_tuple = self.encode_prompt(
+            prompt=prompt,
+            device=device,
+            num_images_per_prompt=num_images_per_prompt,
+            do_classifier_free_guidance=do_classifier_free_guidance,
+            negative_prompt=negative_prompt,
+            prompt_embeds=prompt_embeds,
+            negative_prompt_embeds=negative_prompt_embeds,
+            lora_scale=lora_scale,
+            **kwargs,
+        )
+
+        # concatenate for backwards comp
+        prompt_embeds = torch.cat([prompt_embeds_tuple[1], prompt_embeds_tuple[0]])
+
+        return prompt_embeds
+
+    # Copied from diffusers.pipelines.stable_diffusion.pipeline_stable_diffusion.StableDiffusionPipeline.encode_prompt
+    def encode_prompt(
+        self,
+        prompt: Optional[str],
+        device: torch.device,
+        num_images_per_prompt: int,
+        do_classifier_free_guidance: bool,
+        negative_prompt: Optional[str] = None,
+        prompt_embeds: Optional[torch.FloatTensor] = None,
+        negative_prompt_embeds: Optional[torch.FloatTensor] = None,
+        lora_scale: Optional[float] = None,
+        clip_skip: Optional[int] = None,
+    ) -> torch.FloatTensor:
+        r"""
+        Encodes the prompt into text encoder hidden states.
+
+        Args:
+            prompt (`str` or `List[str]`, *optional*):
+                prompt to be encoded
+            device: (`torch.device`):
+                torch device
+            num_images_per_prompt (`int`):
+                number of images that should be generated per prompt
+            do_classifier_free_guidance (`bool`):
+                whether to use classifier free guidance or not
+            negative_prompt (`str` or `List[str]`, *optional*):
+                The prompt or prompts not to guide the image generation. If not defined, one has to pass
+                `negative_prompt_embeds` instead. Ignored when not using guidance (i.e., ignored if `guidance_scale` is
+                less than `1`).
+            prompt_embeds (`torch.FloatTensor`, *optional*):
+                Pre-generated text embeddings. Can be used to easily tweak text inputs, *e.g.* prompt weighting. If not
+                provided, text embeddings will be generated from `prompt` input argument.
+            negative_prompt_embeds (`torch.FloatTensor`, *optional*):
+                Pre-generated negative text embeddings. Can be used to easily tweak text inputs, *e.g.* prompt
+                weighting. If not provided, negative_prompt_embeds will be generated from `negative_prompt` input
+                argument.
+            lora_scale (`float`, *optional*):
+                A LoRA scale that will be applied to all LoRA layers of the text encoder if LoRA layers are loaded.
+            clip_skip (`int`, *optional*):
+                Number of layers to be skipped from CLIP while computing the prompt embeddings. A value of 1 means that
+                the output of the pre-final layer will be used for computing the prompt embeddings.
+        """
+        # set lora scale so that monkey patched LoRA
+        # function of text encoder can correctly access it
+        if lora_scale is not None and isinstance(self, LoraLoaderMixin):
+            self._lora_scale = lora_scale
+
+            # dynamically adjust the LoRA scale
+            if not USE_PEFT_BACKEND:
+                adjust_lora_scale_text_encoder(self.text_encoder, lora_scale)
+            else:
+                scale_lora_layers(self.text_encoder, lora_scale)
+
+        if prompt is not None and isinstance(prompt, str):
+            batch_size = 1
+        elif prompt is not None and isinstance(prompt, list):
+            batch_size = len(prompt)
+        else:
+            batch_size = prompt_embeds.shape[0]
+
+        if prompt_embeds is None:
+            # textual inversion: process multi-vector tokens if necessary
+            if isinstance(self, TextualInversionLoaderMixin):
+                prompt = self.maybe_convert_prompt(prompt, self.tokenizer)
+
+            text_inputs = self.tokenizer(
+                prompt,
+                padding="max_length",
+                max_length=self.tokenizer.model_max_length,
+                truncation=True,
+                return_tensors="pt",
+            )
+            text_input_ids = text_inputs.input_ids
+            untruncated_ids = self.tokenizer(prompt, padding="longest", return_tensors="pt").input_ids
+
+            if untruncated_ids.shape[-1] >= text_input_ids.shape[-1] and not torch.equal(
+                text_input_ids, untruncated_ids
             ):
+                removed_text = self.tokenizer.batch_decode(
+                    untruncated_ids[:, self.tokenizer.model_max_length - 1 : -1]
+                )
+                logger.warning(
+                    "The following part of your input was truncated because CLIP can only handle sequences up to"
+                    f" {self.tokenizer.model_max_length} tokens: {removed_text}"
+                )
+
+            if hasattr(self.text_encoder.config, "use_attention_mask") and self.text_encoder.config.use_attention_mask:
+                attention_mask = text_inputs.attention_mask.to(device)
+            else:
+                attention_mask = None
+
+            if clip_skip is None:
+                prompt_embeds = self.text_encoder(text_input_ids.to(device), attention_mask=attention_mask)
+                prompt_embeds = prompt_embeds[0]
+            else:
+                prompt_embeds = self.text_encoder(
+                    text_input_ids.to(device), attention_mask=attention_mask, output_hidden_states=True
+                )
+                # Access the `hidden_states` first, that contains a tuple of
+                # all the hidden states from the encoder layers. Then index into
+                # the tuple to access the hidden states from the desired layer.
+                prompt_embeds = prompt_embeds[-1][-(clip_skip + 1)]
+                # We also need to apply the final LayerNorm here to not mess with the
+                # representations. The `last_hidden_states` that we typically use for
+                # obtaining the final prompt representations passes through the LayerNorm
+                # layer.
+                prompt_embeds = self.text_encoder.text_model.final_layer_norm(prompt_embeds)
+
+        if self.text_encoder is not None:
+            prompt_embeds_dtype = self.text_encoder.dtype
+        elif self.unet is not None:
+            prompt_embeds_dtype = self.unet.dtype
+        else:
+            prompt_embeds_dtype = prompt_embeds.dtype
+
+        prompt_embeds = prompt_embeds.to(dtype=prompt_embeds_dtype, device=device)
+
+        bs_embed, seq_len, _ = prompt_embeds.shape
+        # duplicate text embeddings for each generation per prompt, using mps friendly method
+        prompt_embeds = prompt_embeds.repeat(1, num_images_per_prompt, 1)
+        prompt_embeds = prompt_embeds.view(bs_embed * num_images_per_prompt, seq_len, -1)
+
+        # get unconditional embeddings for classifier free guidance
+        if do_classifier_free_guidance and negative_prompt_embeds is None:
+            uncond_tokens: List[str]
+            if negative_prompt is None:
+                uncond_tokens = [""] * batch_size
+            elif prompt is not None and type(prompt) is not type(negative_prompt):
+                raise TypeError(
+                    f"`negative_prompt` should be the same type to `prompt`, but got {type(negative_prompt)} !="
+                    f" {type(prompt)}."
+                )
+            elif isinstance(negative_prompt, str):
+                uncond_tokens = [negative_prompt]
+            elif batch_size != len(negative_prompt):
+                raise ValueError(
+                    f"`negative_prompt`: {negative_prompt} has batch size {len(negative_prompt)}, but `prompt`:"
+                    f" {prompt} has batch size {batch_size}. Please make sure that passed `negative_prompt` matches"
+                    " the batch size of `prompt`."
+                )
+            else:
+                uncond_tokens = negative_prompt
+
+            # textual inversion: process multi-vector tokens if necessary
+            if isinstance(self, TextualInversionLoaderMixin):
+                uncond_tokens = self.maybe_convert_prompt(uncond_tokens, self.tokenizer)
+
+            max_length = prompt_embeds.shape[1]
+            uncond_input = self.tokenizer(
+                uncond_tokens,
+                padding="max_length",
+                max_length=max_length,
+                truncation=True,
+                return_tensors="pt",
+            )
+
+            if hasattr(self.text_encoder.config, "use_attention_mask") and self.text_encoder.config.use_attention_mask:
+                attention_mask = uncond_input.attention_mask.to(device)
+            else:
+                attention_mask = None
+
+            negative_prompt_embeds = self.text_encoder(
+                uncond_input.input_ids.to(device),
+                attention_mask=attention_mask,
+            )
+            negative_prompt_embeds = negative_prompt_embeds[0]
+
+        if do_classifier_free_guidance:
+            # duplicate unconditional embeddings for each generation per prompt, using mps friendly method
+            seq_len = negative_prompt_embeds.shape[1]
+
+            negative_prompt_embeds = negative_prompt_embeds.to(dtype=prompt_embeds_dtype, device=device)
+
+            negative_prompt_embeds = negative_prompt_embeds.repeat(1, num_images_per_prompt, 1)
+            negative_prompt_embeds = negative_prompt_embeds.view(batch_size * num_images_per_prompt, seq_len, -1)
+
+        if isinstance(self, LoraLoaderMixin) and USE_PEFT_BACKEND:
+            # Retrieve the original scale by scaling back the LoRA layers
+            unscale_lora_layers(self.text_encoder, lora_scale)
+
+        return prompt_embeds, negative_prompt_embeds
+
+    # Copied from diffusers.pipelines.stable_diffusion.pipeline_stable_diffusion.StableDiffusionPipeline.prepare_latents
+    def prepare_latents(
+        self,
+        batch_size: int,
+        num_channels_latents: int,
+        height: int,
+        width: int,
+        dtype: torch.dtype,
+        device: torch.device,
+        generator: Union[torch.Generator, List[torch.Generator]],
+        latents: Optional[torch.Tensor] = None,
+    ) -> torch.Tensor:
+        r"""
+        Prepare the latent vectors for diffusion.
+
+        Args:
+            batch_size (int): The number of samples in the batch.
+            num_channels_latents (int): The number of channels in the latent vectors.
+            height (int): The height of the latent vectors.
+            width (int): The width of the latent vectors.
+            dtype (torch.dtype): The data type of the latent vectors.
+            device (torch.device): The device to place the latent vectors on.
+            generator (Union[torch.Generator, List[torch.Generator]]): The generator(s) to use for random number generation.
+            latents (Optional[torch.Tensor]): The pre-existing latent vectors. If None, new latent vectors will be generated.
+
+        Returns:
+            torch.Tensor: The prepared latent vectors.
+        """
+        shape = (batch_size, num_channels_latents, height // self.vae_scale_factor, width // self.vae_scale_factor)
+        if isinstance(generator, list) and len(generator) != batch_size:
+            raise ValueError(
+                f"You have passed a list of generators of length {len(generator)}, but requested an effective batch"
+                f" size of {batch_size}. Make sure the batch size matches the length of the generators."
+            )
+
+        if latents is None:
+            latents = randn_tensor(shape, generator=generator, device=device, dtype=dtype)
+        else:
+            latents = latents.to(device)
+
+        # scale the initial noise by the standard deviation required by the scheduler
+        latents = latents * self.scheduler.init_noise_sigma
+        return latents
+
+    # Copied from diffusers.pipelines.stable_diffusion.pipeline_stable_diffusion.StableDiffusionPipeline.prepare_extra_step_kwargs
+    def prepare_extra_step_kwargs(
+        self, generator: Union[torch.Generator, List[torch.Generator]], eta: float
+    ) -> Dict[str, Any]:
+        r"""
+        Prepare extra keyword arguments for the scheduler step.
+
+        Args:
+            generator (Union[torch.Generator, List[torch.Generator]]): The generator used for sampling.
+            eta (float): The value of eta (η) used with the DDIMScheduler. Should be between 0 and 1.
+
+        Returns:
+            Dict[str, Any]: A dictionary containing the extra keyword arguments for the scheduler step.
+        """
+        # prepare extra kwargs for the scheduler step, since not all schedulers have the same signature
+        # eta (η) is only used with the DDIMScheduler, it will be ignored for other schedulers.
+        # eta corresponds to η in DDIM paper: https://arxiv.org/abs/2010.02502
+        # and should be between [0, 1]
+
+        accepts_eta = "eta" in set(inspect.signature(self.scheduler.step).parameters.keys())
+        extra_step_kwargs = {}
+        if accepts_eta:
+            extra_step_kwargs["eta"] = eta
+
+        # check if the scheduler accepts generator
+        accepts_generator = "generator" in set(inspect.signature(self.scheduler.step).parameters.keys())
+        if accepts_generator:
+            extra_step_kwargs["generator"] = generator
+        return extra_step_kwargs
+
+    def prepare_image(
+        self,
+        image: Union[torch.Tensor, PIL.Image.Image, List[Union[torch.Tensor, PIL.Image.Image]]],
+        width: int,
+        height: int,
+        batch_size: int,
+        num_images_per_prompt: int,
+        device: torch.device,
+        dtype: torch.dtype,
+        do_classifier_free_guidance: bool = False,
+        guess_mode: bool = False,
+    ) -> torch.Tensor:
+        r"""
+        Prepares the input image for processing.
+
+        Args:
+            image (torch.Tensor or PIL.Image.Image or list): The input image(s).
+            width (int): The desired width of the image.
+            height (int): The desired height of the image.
+            batch_size (int): The batch size for processing.
+            num_images_per_prompt (int): The number of images per prompt.
+            device (torch.device): The device to use for processing.
+            dtype (torch.dtype): The data type of the image.
+            do_classifier_free_guidance (bool, optional): Whether to perform classifier-free guidance. Defaults to False.
+            guess_mode (bool, optional): Whether to use guess mode. Defaults to False.
+
+        Returns:
+            torch.Tensor: The prepared image for processing.
+        """
         if not isinstance(image, torch.Tensor):
             if isinstance(image, PIL.Image.Image):
                 image = [image]
@@ -130,7 +725,29 @@ class StableDiffusionReferencePipeline(StableDiffusionPipeline):
 
         return image
 
-    def prepare_ref_latents(self, refimage, batch_size, dtype, device, generator, do_classifier_free_guidance):
+    def prepare_ref_latents(
+        self,
+        refimage: torch.Tensor,
+        batch_size: int,
+        dtype: torch.dtype,
+        device: torch.device,
+        generator: Union[int, List[int]],
+        do_classifier_free_guidance: bool,
+    ) -> torch.Tensor:
+        r"""
+        Prepares reference latents for generating images.
+
+        Args:
+            refimage (torch.Tensor): The reference image.
+            batch_size (int): The desired batch size.
+            dtype (torch.dtype): The data type of the tensors.
+            device (torch.device): The device to perform computations on.
+            generator (int or list): The generator index or a list of generator indices.
+            do_classifier_free_guidance (bool): Whether to use classifier-free guidance.
+
+        Returns:
+            torch.Tensor: The prepared reference latents.
+        """
         refimage = refimage.to(device=device, dtype=dtype)
 
         # encode the mask image into latents space so we can concatenate it to the latents
@@ -158,6 +775,35 @@ class StableDiffusionReferencePipeline(StableDiffusionPipeline):
         ref_image_latents = ref_image_latents.to(device=device, dtype=dtype)
         return ref_image_latents
 
+    # Copied from diffusers.pipelines.stable_diffusion.pipeline_stable_diffusion.StableDiffusionPipeline.run_safety_checker
+    def run_safety_checker(
+        self, image: Union[torch.Tensor, PIL.Image.Image], device: torch.device, dtype: torch.dtype
+    ) -> Tuple[Union[torch.Tensor, PIL.Image.Image], Optional[bool]]:
+        r"""
+        Runs the safety checker on the given image.
+
+        Args:
+            image (Union[torch.Tensor, PIL.Image.Image]): The input image to be checked.
+            device (torch.device): The device to run the safety checker on.
+            dtype (torch.dtype): The data type of the input image.
+
+        Returns:
+            (image, has_nsfw_concept) Tuple[Union[torch.Tensor, PIL.Image.Image], Optional[bool]]: A tuple containing the processed image and
+            a boolean indicating whether the image has a NSFW (Not Safe for Work) concept.
+        """
+        if self.safety_checker is None:
+            has_nsfw_concept = None
+        else:
+            if torch.is_tensor(image):
+                feature_extractor_input = self.image_processor.postprocess(image, output_type="pil")
+            else:
+                feature_extractor_input = self.image_processor.numpy_to_pil(image)
+            safety_checker_input = self.feature_extractor(feature_extractor_input, return_tensors="pt").to(device)
+            image, has_nsfw_concept = self.safety_checker(
+                images=image, clip_input=safety_checker_input.pixel_values.to(dtype)
+            )
+        return image, has_nsfw_concept
+
     @torch.no_grad()
     def __call__(
         self,
@@ -538,7 +1184,12 @@ class StableDiffusionReferencePipeline(StableDiffusionPipeline):
 
             return hidden_states, output_states
 
-        def hacked_DownBlock2D_forward(self, hidden_states, temb=None, **kwargs):
+        def hacked_DownBlock2D_forward(
+            self,
+            hidden_states: torch.FloatTensor,
+            temb: Optional[torch.FloatTensor] = None,
+            **kwargs: Any,
+        ) -> Tuple[torch.FloatTensor, ...]:
             eps = 1e-6
 
             output_states = ()
@@ -588,7 +1239,7 @@ class StableDiffusionReferencePipeline(StableDiffusionPipeline):
             upsample_size: Optional[int] = None,
             attention_mask: Optional[torch.FloatTensor] = None,
             encoder_attention_mask: Optional[torch.FloatTensor] = None,
-        ):
+        ) -> torch.FloatTensor:
             eps = 1e-6
             # TODO(Patrick, William) - attention mask is not used
             for i, (resnet, attn) in enumerate(zip(self.resnets, self.attentions)):
@@ -635,8 +1286,13 @@ class StableDiffusionReferencePipeline(StableDiffusionPipeline):
             return hidden_states
 
         def hacked_UpBlock2D_forward(
-            self, hidden_states, res_hidden_states_tuple, temb=None, upsample_size=None, **kwargs
-        ):
+            self,
+            hidden_states: torch.FloatTensor,
+            res_hidden_states_tuple: Tuple[torch.FloatTensor, ...],
+            temb: Optional[torch.FloatTensor] = None,
+            upsample_size: Optional[int] = None,
+            **kwargs: Any,
+        ) -> torch.FloatTensor:
             eps = 1e-6
             for i, resnet in enumerate(self.resnets):
                 # pop res hidden states