From a782ae5a0a234a49730607f7e0e7e899e4450e2c Mon Sep 17 00:00:00 2001
From: Piotr Sarna <sarna@chiselstrike.com>
Date: Fri, 12 May 2023 10:09:18 +0200
Subject: [PATCH] cursor: add is_empty

---
 core/mvcc/bindings/c/src/lib.rs | 8 +++++++-
 core/mvcc/mvcc-rs/src/cursor.rs | 4 ++++
 2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/core/mvcc/bindings/c/src/lib.rs b/core/mvcc/bindings/c/src/lib.rs
index 16254194a..6da877c12 100644
--- a/core/mvcc/bindings/c/src/lib.rs
+++ b/core/mvcc/bindings/c/src/lib.rs
@@ -156,6 +156,12 @@ pub unsafe extern "C" fn MVCCScanCursorOpen(db: MVCCDatabaseRef) -> MVCCScanCurs
     let (database, runtime) = (&database.db, &database.runtime);
     match runtime.block_on(async move { mvcc_rs::cursor::ScanCursor::new(database).await }) {
         Ok(cursor) => {
+            if cursor.is_empty() {
+                tracing::debug!("Cursor is empty");
+                return MVCCScanCursorRef {
+                    ptr: std::ptr::null_mut(),
+                };
+            }
             tracing::debug!("Cursor open: {cursor:?}");
             MVCCScanCursorRef {
                 ptr: Box::into_raw(Box::new(ScanCursorContext { cursor, db })),
@@ -249,4 +255,4 @@ pub unsafe extern "C" fn MVCCScanCursorPosition(cursor: MVCCScanCursorRef) -> u6
     let cursor_ctx = unsafe { &mut *cursor.ptr };
     let cursor = &mut cursor_ctx.cursor;
     cursor.current_row_id().unwrap_or(0)
-}
\ No newline at end of file
+}
diff --git a/core/mvcc/mvcc-rs/src/cursor.rs b/core/mvcc/mvcc-rs/src/cursor.rs
index 856ce1dbc..7d9455426 100644
--- a/core/mvcc/mvcc-rs/src/cursor.rs
+++ b/core/mvcc/mvcc-rs/src/cursor.rs
@@ -59,4 +59,8 @@ impl<
         self.index += 1;
         self.index < self.row_ids.len()
     }
+
+    pub fn is_empty(&self) -> bool {
+        self.index >= self.row_ids.len()
+    }
 }