1 files changed, 42 insertions, 0 deletions
diff --git a/src/db/lib.rs b/src/db/lib.rs
index fe44b01e..eef3e177 100644
--- a/src/db/lib.rs
+++ b/src/db/lib.rs
@@ -171,6 +171,48 @@ impl Db {
 	}
 }
 
+/// List of supported database engine types
+///
+/// The `enum` holds list of *all* database engines that are are be supported by crate, no matter
+/// if relevant feature is enabled or not. It allows us to distinguish between invalid engine
+/// and valid engine, whose support is not enabled via feature flag.
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+pub enum Engine {
+	Lmdb,
+	Sqlite,
+	Sled,
+}
+
+impl Engine {
+	/// Return variant name as static `&str`
+	pub fn as_str(&self) -> &'static str {
+		match self {
+			Self::Lmdb => "lmdb",
+			Self::Sqlite => "sqlite",
+			Self::Sled => "sled",
+		}
+	}
+}
+
+impl std::fmt::Display for Engine {
+	fn fmt(&self, fmt: &mut std::fmt::Formatter) -> std::fmt::Result {
+		self.as_str().fmt(fmt)
+	}
+}
+
+impl std::str::FromStr for Engine {
+	type Err = Error;
+
+	fn from_str(text: &str) -> Result<Engine> {
+		match text {
+			"lmdb" | "heed" => Ok(Self::Lmdb),
+			"sqlite" | "sqlite3" | "rusqlite" => Ok(Self::Sqlite),
+			"sled" => Ok(Self::Sled),
+			kind => Err(Error(format!("Invalid DB engine: {}", kind).into())),
+		}
+	}
+}
+
 #[allow(clippy::len_without_is_empty)]
 impl Tree {
 	#[inline]