safety warning

cozorocks/src/lib.rs

@@ -431,8 +431,11 @@ impl<'a> IteratorPtr<'a> {
     pub fn seek_for_prev(&self, key: impl AsRef<[u8]>) {
         IteratorBridge::do_seek_for_prev(self, key.as_ref())
     }
+
     #[inline]
-    pub fn key(&self) -> Option<SlicePtr> {
+    /// # Safety
+    /// `next()` must not be called on the iterator when the returned value is still used
+    pub unsafe fn key(&self) -> Option<SlicePtr> {
         if self.is_valid() {
             Some(SlicePtr::Plain(IteratorBridge::key_raw(self)))
         } else {
@@ -440,7 +443,9 @@ impl<'a> IteratorPtr<'a> {
         }
     }
     #[inline]
-    pub fn val(&self) -> Option<SlicePtr> {
+    /// # Safety
+    /// `next()` must not be called on the iterator when the returned value is still used
+    pub unsafe fn val(&self) -> Option<SlicePtr> {
         if self.is_valid() {
             Some(SlicePtr::Plain(IteratorBridge::value_raw(self)))
         } else {
@@ -448,7 +453,9 @@ impl<'a> IteratorPtr<'a> {
         }
     }
     #[inline]
-    pub fn pair(&self) -> Option<(SlicePtr, SlicePtr)> {
+    /// # Safety
+    /// `next()` must not be called on the iterator when the returned value is still used
+    pub unsafe fn pair(&self) -> Option<(SlicePtr, SlicePtr)> {
         if self.is_valid() {
             Some((SlicePtr::Plain(IteratorBridge::key_raw(self)),
                   SlicePtr::Plain(IteratorBridge::value_raw(self))))

src/db/ddl.rs

@@ -285,7 +285,7 @@ impl<'s> Session<'s> {
 
         let it = self.txn.iterator(true, &self.perm_cf);
         it.seek(&prefix);
-        while let Some(val) = it.key() {
+        while let Some(val) = unsafe { it.key() } {
             let cur = Tuple::new(val);
             if !cur.starts_with(&prefix) {
                 break;
@@ -301,7 +301,7 @@ impl<'s> Session<'s> {
 
         let it = self.txn.iterator(false, &self.temp_cf);
         it.seek(&prefix);
-        while let Some(val) = it.key() {
+        while let Some(val) = unsafe { it.key() } {
             let cur = Tuple::new(val);
             if !cur.starts_with(&prefix) {
                 break;
@@ -325,7 +325,7 @@ impl<'s> Session<'s> {
         } else {
             let it = self.txn.iterator(false, &self.temp_cf);
             it.seek(&key);
-            if let Some(found_key) = it.key() {
+            if let Some(found_key) = unsafe { it.key() } {
                 let found_key_tuple = Tuple::new(found_key);
                 if found_key_tuple.starts_with(&key) {
                     let mut ikey = Tuple::with_null_prefix();

src/db/engine.rs

@@ -241,7 +241,7 @@ mod tests {
             }
             let it = sess.txn.iterator(true, &sess.perm_cf);
             it.to_first();
-            while let Some((key, val)) = it.pair() {
+            while let Some((key, val)) = unsafe { it.pair() } {
                 println!("a: {:?} {:?}", key.as_ref(), val.as_ref());
                 println!("v: {:?} {:?}", Tuple::new(key), Tuple::new(val));
                 it.next();

src/db/env.rs

@@ -100,7 +100,7 @@ impl<'s> Session<'s> {
         let it = self.txn.iterator(false, &self.temp_cf);
         it.seek(&prefix);
         let mut to_delete = vec![];
-        while let Some(val) = it.key() {
+        while let Some(val) = unsafe { it.key() } {
             let cur = Tuple::new(val);
             if cur.starts_with(&prefix) {
                 if let Some(name) = cur.get(1) {
@@ -142,7 +142,7 @@ impl<'s> Session<'s> {
         prefix.push_int(self.stack_depth as i64);
         let it = self.txn.iterator(false, &self.temp_cf);
         it.seek(&prefix);
-        while let Some(val) = it.key() {
+        while let Some(val) = unsafe { it.key() } {
             let cur = Tuple::new(val);
             if cur.starts_with(&prefix) {
                 let mut ikey = Tuple::with_prefix(cur.get_prefix());
@@ -177,7 +177,7 @@ impl<'s> Session<'s> {
         tuple.push_str(name);
         let it = self.txn.iterator(false, &self.temp_cf);
         it.seek(&tuple);
-        if let Some((tk, vk)) = it.pair() {
+        if let Some((tk, vk)) = unsafe { it.pair() } {
             let k = Tuple::new(tk);
             if k.starts_with(&tuple) {
                 return Ok(Some(Tuple::new(vk)));

src/db/eval.rs

@@ -1240,14 +1240,14 @@ mod tests {
 
             let it = env.txn.iterator(false, &env.perm_cf);
             it.to_first();
-            while let Some((k, v)) = it.pair() {
+            while let Some((k, v)) = unsafe { it.pair() } {
                 println!("{:?}, {:?}", Tuple::new(k), Tuple::new(v));
                 it.next();
             }
 
             let it = env.txn.iterator(false, &env.temp_cf);
             it.to_first();
-            while let Some((k, v)) = it.pair() {
+            while let Some((k, v)) = unsafe { it.pair() } {
                 println!("{:?}, {:?}", Tuple::new(k), Tuple::new(v));
                 it.next();
             }

src/db/iterator.rs

@@ -5,7 +5,7 @@ use cozorocks::IteratorPtr;
 use crate::db::eval::{compare_tuple_by_keys, tuple_eval};
 use crate::db::table::{ColId, TableId};
 use crate::error::CozoError::LogicError;
-use crate::error::{CozoError, Result};
+use crate::error::{Result};
 use crate::relation::data::{DataKind, EMPTY_DATA};
 use crate::relation::table::MegaTuple;
 use crate::relation::tuple::{CowSlice, CowTuple, OwnTuple, Tuple};
@@ -404,12 +404,14 @@ impl<'a> Iterator for NodeIterator<'a> {
         } else {
             self.started = true;
         }
-        self.it.pair().map(|(k, v)| {
-            Ok(MegaTuple {
-                keys: vec![Tuple::new(k).into()],
-                vals: vec![Tuple::new(v).into()],
+        unsafe {
+            self.it.pair().map(|(k, v)| {
+                Ok(MegaTuple {
+                    keys: vec![Tuple::new(k).into()],
+                    vals: vec![Tuple::new(v).into()],
+                })
             })
-        })
+        }
     }
 }
 
@@ -428,7 +430,7 @@ impl<'a> Iterator for EdgeIterator<'a> {
             self.started = true;
         }
         loop {
-            match self.it.pair() {
+            match unsafe { self.it.pair() } {
                 None => return None,
                 Some((k, v)) => {
                     let vt = Tuple::new(v);
@@ -462,7 +464,7 @@ impl<'a> Iterator for EdgeKeyOnlyBwdIterator<'a> {
             self.started = true;
         }
         loop {
-            match self.it.pair() {
+            match unsafe { self.it.pair() } {
                 None => return None,
                 Some((_k, rev_k)) => {
                     let rev_k_tuple = Tuple::new(rev_k);

src/db/mutation.rs

@@ -289,7 +289,7 @@ mod tests {
             sess.rollback().unwrap();
             let it = sess.txn.iterator(true, &sess.perm_cf);
             it.to_first();
-            while let Some((k, v)) = it.pair() {
+            while let Some((k, v)) = unsafe { it.pair() } {
                 println!("K: {:?}, V: {:?}", Tuple::new(k), Tuple::new(v));
                 it.next();
             }
@@ -339,7 +339,7 @@ mod tests {
 
             let it = sess.txn.iterator(true, &sess.perm_cf);
             it.to_first();
-            while let Some((k, v)) = it.pair() {
+            while let Some((k, v)) = unsafe { it.pair() } {
                 println!("K: {:?}, V: {:?}", Tuple::new(k), Tuple::new(v));
                 it.next();
             }