Add check if dataset exists (#327)

src/eva/vision/data/datasets/_validators.py

@@ -1,5 +1,7 @@
 """Dataset validation related functions."""
 
+import os
+
 from typing_extensions import List, Tuple
 
 from eva.vision.data.datasets import vision
@@ -42,3 +44,16 @@ def check_dataset_integrity(
             f"({(dataset_classes[0], dataset_classes[-1])}) does not match the expected "
             f"ones ({first_and_last_labels}). {_SUFFIX_ERROR_MESSAGE}"
         )
+
+
+def check_dataset_exists(dataset_dir: str, download_available: bool) -> None:
+    """Verifies that the dataset folder exists.
+
+    Raise:
+        FileNotFoundError: If the dataset folder does not exist.
+    """
+    if not os.path.isdir(dataset_dir):
+        error_message = f"Dataset not found at '{dataset_dir}'."
+        if download_available:
+            error_message += " You can set `download=True` to download the dataset automatically."
+        raise FileNotFoundError(error_message)

src/eva/vision/data/datasets/classification/bach.py

@@ -96,24 +96,25 @@ def class_to_idx(self) -> Dict[str, int]:
         return {"Benign": 0, "InSitu": 1, "Invasive": 2, "Normal": 3}
 
     @property
-    def dataset_path(self) -> str:
+    def _dataset_path(self) -> str:
         """Returns the path of the image data of the dataset."""
         return os.path.join(self._root, "ICIAR2018_BACH_Challenge", "Photos")
 
     @override
     def filename(self, index: int) -> str:
         image_path, _ = self._samples[self._indices[index]]
-        return os.path.relpath(image_path, self.dataset_path)
+        return os.path.relpath(image_path, self._dataset_path)
 
     @override
     def prepare_data(self) -> None:
         if self._download:
             self._download_dataset()
+        _validators.check_dataset_exists(self._root, True)
 
     @override
     def configure(self) -> None:
         self._samples = folder.make_dataset(
-            directory=self.dataset_path,
+            directory=self._dataset_path,
             class_to_idx=self.class_to_idx,
             extensions=(".tif"),
         )
@@ -145,7 +146,7 @@ def __len__(self) -> int:
     def _download_dataset(self) -> None:
         """Downloads the dataset."""
         for resource in self._resources:
-            if os.path.isdir(self.dataset_path):
+            if os.path.isdir(self._dataset_path):
                 continue
 
             self._print_license()

src/eva/vision/data/datasets/classification/crc.py

@@ -95,12 +95,13 @@ def class_to_idx(self) -> Dict[str, int]:
     @override
     def filename(self, index: int) -> str:
         image_path, *_ = self._samples[index]
-        return os.path.relpath(image_path, self._dataset_dir)
+        return os.path.relpath(image_path, self._dataset_path)
 
     @override
     def prepare_data(self) -> None:
         if self._download:
             self._download_dataset()
+        _validators.check_dataset_exists(self._root, True)
 
     @override
     def configure(self) -> None:
@@ -135,7 +136,7 @@ def __len__(self) -> int:
         return len(self._samples)
 
     @property
-    def _dataset_dir(self) -> str:
+    def _dataset_path(self) -> str:
         """Returns the full path of dataset directory."""
         dataset_dirs = {
             "train": os.path.join(self._root, "NCT-CRC-HE-100K"),
@@ -150,7 +151,7 @@ def _dataset_dir(self) -> str:
     def _make_dataset(self) -> List[Tuple[str, int]]:
         """Builds the dataset for the specified split."""
         dataset = folder.make_dataset(
-            directory=self._dataset_dir,
+            directory=self._dataset_path,
             class_to_idx=self.class_to_idx,
             extensions=(".tif"),
         )

src/eva/vision/data/datasets/classification/mhist.py

@@ -56,6 +56,10 @@ def filename(self, index: int) -> str:
         image_filename, _ = self._samples[index]
         return image_filename
 
+    @override
+    def prepare_data(self) -> None:
+        _validators.check_dataset_exists(self._root, False)
+
     @override
     def configure(self) -> None:
         self._samples = self._make_dataset()

src/eva/vision/data/datasets/classification/patch_camelyon.py

@@ -114,6 +114,7 @@ def filename(self, index: int) -> str:
     def prepare_data(self) -> None:
         if self._download:
             self._download_dataset()
+        _validators.check_dataset_exists(self._root, True)
 
     @override
     def validate(self) -> None:

src/eva/vision/data/datasets/classification/total_segmentator.py

@@ -108,6 +108,7 @@ def filename(self, index: int) -> str:
     def prepare_data(self) -> None:
         if self._download:
             self._download_dataset()
+        _validators.check_dataset_exists(self._root, True)
 
     @override
     def configure(self) -> None: