add wrapper struct with case-folding get impl

rslib/src/sync/media/database/client/mod.rs

@@ -18,6 +18,20 @@ use crate::prelude::*;
 
 pub mod changetracker;
 
+pub struct Checksums(HashMap<String, Sha1Hash>);
+
+impl Checksums {
+    // case-fold filenames when checking files to be imported
+    // to account for case-insensitive filesystems
+    pub fn get(&self, key: impl AsRef<str>) -> Option<&Sha1Hash> {
+        self.0.get(key.as_ref().to_lowercase().as_str())
+    }
+
+    pub fn contains_key(&self, key: impl AsRef<str>) -> bool {
+        self.get(key).is_some()
+    }
+}
+
 #[derive(Debug, PartialEq, Eq)]
 pub struct MediaEntry {
     pub fname: String,