tweak(metadb): swap NotFound error with MetaNotFound

Author: DevBlocky

src/lib.rs

@@ -69,6 +69,8 @@ pub enum ForcepError {
     MetaSer(bson::ser::Error),
     /// Error with metadata sled database operation
     MetaDb(sled::Error),
+    /// The entry was found successfully, but the metadata was strangely not present
+    MetaNotFound,
     /// The entry for the specified key is not found
     NotFound,
 }
@@ -84,6 +86,7 @@ impl std::fmt::Display for ForcepError {
             Self::MetaDe(e) => write!(fmt, "there was a problem deserializing metadata: {}", e),
             Self::MetaSer(e) => write!(fmt, "there was a problem serializing metadata: {}", e),
             Self::MetaDb(e) => write!(fmt, "an error with the metadata database occurred: {}", e),
+            Self::MetaNotFound => write!(fmt, "the entry for the key provided was found, but the metadata was strangely not present"),
             Self::NotFound => write!(fmt, "the entry for the key provided was not found"),
         }
     }
@@ -95,6 +98,7 @@ impl error::Error for ForcepError {
             Self::MetaDe(e) => Some(e),
             Self::MetaSer(e) => Some(e),
             Self::MetaDb(e) => Some(e),
+            Self::MetaNotFound => None,
             Self::NotFound => None,
         }
     }

src/metadata.rs

@@ -175,7 +175,7 @@ impl MetaDb {
     pub fn get_metadata(&self, key: &[u8]) -> Result<Metadata> {
         let data = match self.db.get(key) {
             Ok(Some(data)) => data,
-            Ok(None) => return Err(ForcepError::NotFound),
+            Ok(None) => return Err(ForcepError::MetaNotFound),
             Err(e) => return Err(ForcepError::MetaDb(e)),
         };
         Metadata::deserialize(&data)
@@ -196,7 +196,7 @@ impl MetaDb {
     pub fn remove_metadata_for(&self, key: &[u8]) -> Result<Metadata> {
         match self.db.remove(key) {
             Ok(Some(m)) => Metadata::deserialize(&m[..]),
-            Ok(None) => Err(ForcepError::NotFound),
+            Ok(None) => Err(ForcepError::MetaNotFound),
             Err(e) => Err(ForcepError::MetaDb(e)),
         }
     }
@@ -207,7 +207,7 @@ impl MetaDb {
         let mut meta = match self.db.get(key) {
             Ok(Some(entry)) => Metadata::deserialize(&entry[..])?,
             Err(e) => return Err(ForcepError::MetaDb(e)),
-            Ok(None) => return Err(ForcepError::NotFound),
+            Ok(None) => return Err(ForcepError::MetaNotFound),
         };
         meta.last_accessed = now_since_epoch();
         meta.hits += 1;