From 1b7ed0300e4a40a1ffe65f339d955eb87b5daa23 Mon Sep 17 00:00:00 2001
From: Adrian Tofting <adrian@vake.ai>
Date: Mon, 3 Jul 2023 10:47:22 +0200
Subject: [PATCH] Revert "Remove required os.exists for paths"

This reverts commit 84bf62b944326c33d5ba8efdcab615c65b124792.
---
 torchgeo/datasets/geo.py | 37 +++++++++++++++++++++++++++++++++----
 1 file changed, 33 insertions(+), 4 deletions(-)

diff --git a/torchgeo/datasets/geo.py b/torchgeo/datasets/geo.py
index c40f880e2bf..fda6f24b859 100644
--- a/torchgeo/datasets/geo.py
+++ b/torchgeo/datasets/geo.py
@@ -438,14 +438,43 @@ def list_files(self, filename_glob: Optional[str] = None) -> list[str]:
         # using set to remove any duplicates if directories are overlapping
         filepaths: set[str] = set()
         for dir_or_file in paths:
-            if os.path.isdir(dir_or_file):
-                pathname = os.path.join(dir_or_file, "**", filename_glob)
-                filepaths |= set(glob.iglob(pathname, recursive=True))
+            if os.path.exists(dir_or_file):
+                if os.path.isfile(dir_or_file):
+                    filepaths.add(dir_or_file)
+                else:
+                    pathname = os.path.join(dir_or_file, "**", filename_glob)
+                    filepaths |= set(glob.iglob(pathname, recursive=True))
             else:
-                filepaths.add(dir_or_file)
+                filepaths |= self.handle_nonlocal_path(dir_or_file)
 
         return list(filepaths)
 
+    def handle_nonlocal_path(self, path: str) -> set[str]:
+        """Override this method if your path can not be interpreted by os module.
+
+        See docs for Advanced Datasets
+            https://rasterio.readthedocs.io/en/stable/topics/datasets.html
+        `fiona.listdir` can be used to list files in such directories:
+            https://fiona.readthedocs.io/en/stable/fiona.html#fiona.io.MemoryFile.listdir
+
+        Args:
+            path: directory, cloud storage blob or archive to be listed
+
+        Returns:
+            set of paths pointing to files
+
+        Raises:
+            RuntimeError: if the path is not found locally,
+                or this method is not overridden by child
+        """
+        raise RuntimeError(
+            f"Dataset not found in `{path}` "
+            "either specify a different `root` directory or make sure you "
+            "have manually downloaded the dataset as instructed in the documentation."
+            "If this is a remote file or archive "
+            "please override this method and return the filepath(s) as a set."
+        )
+
     def __getitem__(self, query: BoundingBox) -> dict[str, Any]:
         """Retrieve image/mask and metadata indexed by query.