From 52f63b2af089b9a23dec04fae01ac1bdeaf57fc0 Mon Sep 17 00:00:00 2001
From: PThorpe92 <preston@turso.tech>
Date: Thu, 17 Jul 2025 23:25:11 -0400
Subject: [PATCH] Impl truncate for simulator

---
 simulator/runner/file.rs | 32 ++++++++++++++++++++++++++++++++
 1 file changed, 32 insertions(+)

diff --git a/simulator/runner/file.rs b/simulator/runner/file.rs
index 1be2cb48b..f78ae3287 100644
--- a/simulator/runner/file.rs
+++ b/simulator/runner/file.rs
@@ -225,6 +225,38 @@ impl File for SimulatorFile {
     fn size(&self) -> Result<u64> {
         self.inner.size()
     }
+
+    fn truncate(
+        &self,
+        len: usize,
+        mut c: turso_core::Completion,
+    ) -> Result<Arc<turso_core::Completion>> {
+        if self.fault.get() {
+            return Err(turso_core::LimboError::InternalError(
+                FAULT_ERROR_MSG.into(),
+            ));
+        }
+        if let Some(latency) = self.generate_latency_duration() {
+            let CompletionType::Truncate(truncate_completion) = &mut c.completion_type else {
+                unreachable!();
+            };
+            let before = self.rng.borrow_mut().gen_bool(0.5);
+            let dummy_complete = Box::new(|_| {});
+            let prev_complete =
+                std::mem::replace(&mut truncate_completion.complete, dummy_complete);
+            let new_complete = move |res| {
+                if before {
+                    std::thread::sleep(latency);
+                }
+                (prev_complete)(res);
+                if !before {
+                    std::thread::sleep(latency);
+                }
+            };
+            truncate_completion.complete = Box::new(new_complete);
+        };
+        self.inner.truncate(len, c)
+    }
 }
 
 impl Drop for SimulatorFile {