Support directory deletion

Author: estebank

.github/workflows/rust.yml

@@ -18,7 +18,7 @@ jobs:
     strategy:
       matrix:
         # Always run MSRV too!
-        rust: ["stable", "1.86"]
+        rust: ["stable", "1.87"]
         features: ['log', 'defmt-log', '""']
     steps:
     - uses: actions/checkout@v4

Cargo.toml

@@ -11,7 +11,7 @@ repository = "https://github.com/rust-embedded-community/embedded-sdmmc-rs"
 version = "0.9.0"
 
 # Make sure to update the CI too!
-rust-version = "1.86"
+rust-version = "1.87"
 
 [dependencies]
 byteorder = {version = "1", default-features = false}

src/lib.rs

@@ -191,8 +191,10 @@ where
     OpenedDirAsFile,
     /// You can't open a file as a directory
     OpenedFileAsDir,
-    /// You can't delete a directory as a file
+    /// You can't delete a directory as a file [no longer being emitted]
     DeleteDirAsFile,
+    /// You can't delete a non-empty directory
+    DeleteNonEmptyDir,
     /// You can't close a volume with open files or directories
     VolumeStillInUse,
     /// You can't open a volume twice
@@ -255,6 +257,7 @@ impl<E: Debug> embedded_io::Error for Error<E> {
             Error::OpenedDirAsFile
             | Error::OpenedFileAsDir
             | Error::DeleteDirAsFile
+            | Error::DeleteNonEmptyDir
             | Error::BadCluster
             | Error::ConversionError
             | Error::UnterminatedFatChain => ErrorKind::InvalidData,
@@ -294,6 +297,7 @@ where
             Error::OpenedDirAsFile => write!(f, "cannot open directory as file"),
             Error::OpenedFileAsDir => write!(f, "cannot open file as directory"),
             Error::DeleteDirAsFile => write!(f, "cannot delete directory as file"),
+            Error::DeleteNonEmptyDir => write!(f, "cannot delete a non-empty directory"),
             Error::VolumeStillInUse => write!(f, "volume is still in use"),
             Error::VolumeAlreadyOpen => write!(f, "cannot open volume twice"),
             Error::Unsupported => write!(f, "unsupported operation"),

src/volume_mgr.rs

@@ -665,26 +665,62 @@ where
         let data = data.deref_mut();
 
         let dir_idx = data.get_dir_by_id(directory)?;
-        let dir_info = &data.open_dirs[dir_idx];
-        let volume_idx = data.get_volume_by_id(dir_info.raw_volume)?;
+        let parent_dir_info = &data.open_dirs[dir_idx];
+        let volume_idx = data.get_volume_by_id(parent_dir_info.raw_volume)?;
         let sfn = name.to_short_filename().map_err(Error::FilenameError)?;
 
         let dir_entry = match &data.open_volumes[volume_idx].volume_type {
-            VolumeType::Fat(fat) => fat.find_directory_entry(&mut data.block_cache, dir_info, &sfn),
+            VolumeType::Fat(fat) => {
+                fat.find_directory_entry(&mut data.block_cache, parent_dir_info, &sfn)
+            }
         }?;
 
         if dir_entry.attributes.is_directory() {
-            return Err(Error::DeleteDirAsFile);
-        }
-
-        if data.file_is_open(dir_info.raw_volume, &dir_entry) {
+            // Find the directory to be deleted, so that we can check its contents.
+            let dir_info = if data
+                .open_dirs
+                .iter()
+                .find(|dir_info| dir_info.cluster == dir_entry.cluster)
+                .is_some()
+            {
+                // Subdirectory is already open.
+                return Err(Error::DirAlreadyOpen);
+            } else {
+                // The subdirectory isn't yet open. Open it in order to be able to list it.
+                let raw_directory = RawDirectory(data.id_generator.generate());
+                DirectoryInfo {
+                    raw_directory,
+                    raw_volume: data.open_volumes[volume_idx].raw_volume,
+                    cluster: dir_entry.cluster,
+                }
+            };
+            // Can only delete directories that are already empty.
+            let mut count = 0;
+            // Equivalent to `self.iterate_dir(raw_dir, |_| count += 1)?;`, without locking again.
+            match &data.open_volumes[volume_idx].volume_type {
+                VolumeType::Fat(fat) => {
+                    fat.iterate_dir(&mut data.block_cache, &dir_info, |de| {
+                        // Hide all the LFN directory entries
+                        if !de.attributes.is_lfn()
+                            && de.name != ShortFileName::this_dir()
+                            && de.name != ShortFileName::parent_dir()
+                        {
+                            count += 1;
+                        }
+                    })?;
+                }
+            }
+            if count != 0 {
+                return Err(Error::DeleteNonEmptyDir);
+            }
+        } else if data.file_is_open(parent_dir_info.raw_volume, &dir_entry) {
             return Err(Error::FileAlreadyOpen);
         }
 
-        let volume_idx = data.get_volume_by_id(dir_info.raw_volume)?;
+        let volume_idx = data.get_volume_by_id(parent_dir_info.raw_volume)?;
         match &data.open_volumes[volume_idx].volume_type {
             VolumeType::Fat(fat) => {
-                fat.delete_directory_entry(&mut data.block_cache, dir_info, &sfn)?
+                fat.delete_directory_entry(&mut data.block_cache, parent_dir_info, &sfn)?
             }
         }
 

tests/directories.rs

@@ -592,6 +592,49 @@ fn make_directory() {
     volume_mgr.close_file(new_file).expect("close file");
 }
 
+#[test]
+fn delete_directory() {
+    let time_source = utils::make_time_source();
+    let disk = utils::make_block_device(utils::DISK_SOURCE).unwrap();
+    let volume_mgr = embedded_sdmmc::VolumeManager::new(disk, time_source);
+
+    let fat32_volume = volume_mgr
+        .open_raw_volume(embedded_sdmmc::VolumeIdx(1))
+        .expect("open volume 1");
+
+    let root_dir = volume_mgr
+        .open_root_dir(fat32_volume)
+        .expect("open root dir");
+
+    volume_mgr.make_dir_in_dir(root_dir, "FOOBAR").unwrap();
+
+    let dir = volume_mgr.open_dir(root_dir, "FOOBAR").unwrap();
+
+    assert!(matches!(
+        volume_mgr.delete_file_in_dir(root_dir, "FOOBAR"),
+        Err(embedded_sdmmc::Error::DirAlreadyOpen)
+    ));
+
+    assert!(matches!(
+        volume_mgr.delete_file_in_dir(root_dir, "FOO"),
+        Err(embedded_sdmmc::Error::NotFound)
+    ));
+
+    volume_mgr.close_dir(dir).unwrap();
+
+    volume_mgr.delete_file_in_dir(root_dir, "FOOBAR").unwrap();
+
+    assert!(matches!(
+        volume_mgr.delete_file_in_dir(root_dir, "FOOBAR"),
+        Err(embedded_sdmmc::Error::NotFound)
+    ));
+
+    assert!(matches!(
+        volume_mgr.open_dir(root_dir, "FOOBAR"),
+        Err(embedded_sdmmc::Error::NotFound)
+    ));
+}
+
 // ****************************************************************************
 //
 // End Of File