feat: insert if not exists

grovedb/src/lib.rs

@@ -212,6 +212,21 @@ impl GroveDb {
         Ok(())
     }
 
+    pub fn insert_if_not_exists(
+        &mut self,
+        path: &[&[u8]],
+        key: Vec<u8>,
+        element: subtree::Element,
+    ) -> Result<bool, Error> {
+        if self.get(path, &key).is_ok() {
+            return Ok(false);
+        }
+        match self.insert(path, key, element) {
+            Ok(_) => Ok(true),
+            Err(e) => Err(e),
+        }
+    }
+
     pub fn get(&self, path: &[&[u8]], key: &[u8]) -> Result<subtree::Element, Error> {
         match self.get_raw(path, key)? {
             Element::Reference(reference_path) => self.follow_reference(reference_path),

grovedb/src/tests.rs

@@ -315,3 +315,28 @@ fn test_checkpoint() {
         Err(Error::InvalidPath(_))
     ));
 }
+
+#[test]
+fn test_insert_if_not_exists() {
+    let mut db = make_grovedb();
+
+    // Insert twice at the same path
+    assert_eq!(
+        db.insert_if_not_exists(&[TEST_LEAF], b"key1".to_vec(), Element::empty_tree())
+            .expect("Provided valid path"),
+        true
+    );
+    assert_eq!(
+        db.insert_if_not_exists(&[TEST_LEAF], b"key1".to_vec(), Element::empty_tree())
+            .expect("Provided valid path"),
+        false
+    );
+
+    // Should propagate errors from insertion
+    let result = db.insert_if_not_exists(
+        &[TEST_LEAF, b"unknown"],
+        b"key1".to_vec(),
+        Element::empty_tree(),
+    );
+    assert!(matches!(result, Err(Error::InvalidPath(_))));
+}