From ae709f04fe73a595bb69cc511b7d66dace2f21b9 Mon Sep 17 00:00:00 2001
From: Pekka Enberg <penberg@iki.fi>
Date: Sat, 2 Sep 2023 13:26:44 +0300
Subject: [PATCH] Make some opcodes wait for completion

---
 core/btree.rs | 13 +++++++++----
 core/vdbe.rs  |  2 ++
 2 files changed, 11 insertions(+), 4 deletions(-)

diff --git a/core/btree.rs b/core/btree.rs
index e8e38a6d3..6dfcac01a 100644
--- a/core/btree.rs
+++ b/core/btree.rs
@@ -26,6 +26,10 @@ impl Cursor {
         }
     }
 
+    pub fn is_empty(&self) -> bool {
+        self.page.borrow().is_none()
+    }
+
     pub fn rewind(&mut self) -> Result<()> {
         self.page
             .replace(Some(self.pager.read_page(self.root_page)?));
@@ -34,10 +38,6 @@ impl Cursor {
         Ok(())
     }
 
-    pub fn is_empty(&self) -> bool {
-        self.page.borrow().is_none()
-    }
-
     pub fn next(&mut self) -> Result<Option<Record>> {
         let result = self.record.take();
         let next = self.get_next_record()?;
@@ -45,6 +45,11 @@ impl Cursor {
         Ok(result)
     }
 
+    pub fn wait_for_completion(&mut self) -> Result<()> {
+        // TODO: Wait for pager I/O to complete
+        Ok(())
+    }
+
     pub fn record(&self) -> Result<Ref<Option<Record>>> {
         Ok(self.record.borrow())
     }
diff --git a/core/vdbe.rs b/core/vdbe.rs
index ae1a0f57b..8cb5c0bc3 100644
--- a/core/vdbe.rs
+++ b/core/vdbe.rs
@@ -216,6 +216,7 @@ impl Program {
                     pc_if_empty,
                 } => {
                     let cursor = state.cursors.get_mut(cursor_id).unwrap();
+                    cursor.wait_for_completion()?;
                     if cursor.is_empty() {
                         state.pc = *pc_if_empty;
                     } else {
@@ -256,6 +257,7 @@ impl Program {
                     pc_if_next,
                 } => {
                     let cursor = state.cursors.get_mut(cursor_id).unwrap();
+                    cursor.wait_for_completion()?;
                     if cursor.has_record() {
                         state.pc = *pc_if_next;
                     } else {