bind/rust: Fix lifetime issue with pragma_query

Shallow cloning in Row ended up invalidating the pointer
to value

bindings/rust/examples/example.rs

@@ -13,7 +13,7 @@ async fn main() {
         .unwrap();
 
     conn.pragma_query("journal_mode", |row| {
-        println!("{}", row.get_value(0));
+        println!("{:?}", row.get_value(0));
         Ok(())
     })
     .unwrap();

bindings/rust/src/lib.rs

@@ -124,17 +124,28 @@ impl Connection {
         Ok(statement)
     }
 
-    pub fn pragma_query<F>(&self, pragma_name: &str, f: F) -> Result<()>
+    pub fn pragma_query<F>(&self, pragma_name: &str, mut f: F) -> Result<()>
     where
-        F: FnMut(&limbo_core::Row) -> limbo_core::Result<()>,
+        F: FnMut(&Row) -> limbo_core::Result<()>,
     {
         let conn = self
             .inner
             .lock()
             .map_err(|e| Error::MutexError(e.to_string()))?;
 
-        conn.pragma_query(pragma_name, f)
-            .map_err(|e| Error::SqlExecutionFailure(e.to_string()))
+        let rows: Vec<Row> = conn
+            .pragma_query(pragma_name)
+            .map_err(|e| Error::SqlExecutionFailure(e.to_string()))?
+            .iter()
+            .map(|row| row.iter().collect::<Row>())
+            .collect();
+
+        rows.iter().try_for_each(|row| {
+            f(row).map_err(|e| {
+                Error::SqlExecutionFailure(format!("Error executing user defined function: {}", e))
+            })
+        })?;
+        Ok(())
     }
 }
 
@@ -320,3 +331,20 @@ impl Row {
         self.values.len()
     }
 }
+
+impl<'a> FromIterator<&'a limbo_core::Value> for Row {
+    fn from_iter<T: IntoIterator<Item = &'a limbo_core::Value>>(iter: T) -> Self {
+        let values = iter
+            .into_iter()
+            .map(|v| match v {
+                limbo_core::Value::Integer(i) => limbo_core::Value::Integer(*i),
+                limbo_core::Value::Null => limbo_core::Value::Null,
+                limbo_core::Value::Float(f) => limbo_core::Value::Float(*f),
+                limbo_core::Value::Text(s) => limbo_core::Value::Text(s.clone()),
+                limbo_core::Value::Blob(b) => limbo_core::Value::Blob(b.clone()),
+            })
+            .collect();
+
+        Row { values }
+    }
+}

core/error.rs

@@ -53,6 +53,8 @@ pub enum LimboError {
     SchemaLocked,
     #[error("Database Connection is read-only")]
     ReadOnly,
+    #[error("Database is busy")]
+    Busy,
 }
 
 #[macro_export]

core/lib.rs

@@ -89,10 +89,6 @@ pub(crate) type MvStore = mvcc::MvStore<mvcc::LocalClock>;
 
 pub(crate) type MvCursor = mvcc::cursor::ScanCursor<mvcc::LocalClock>;
 
-// Not so sure if we should expose this row to the user
-// or make a wrapper around it to sharp some corners
-pub type Row = vdbe::Row;
-
 pub struct Database {
     mv_store: Option<Rc<MvStore>>,
     schema: Arc<RwLock<Schema>>,
@@ -586,22 +582,30 @@ impl Connection {
         Ok(())
     }
 
-    pub fn pragma_query<F>(self: &Rc<Connection>, pragma_name: &str, mut f: F) -> Result<()>
-    where
-        F: FnMut(&Row) -> Result<()>,
-    {
+    // Clearly there is something to improve here, Vec<Vec<Value>> isn't a couple of tea
+    pub fn pragma_query(self: &Rc<Connection>, pragma_name: &str) -> Result<Vec<Vec<Value>>> {
         let pragma = format!("PRAGMA {}", pragma_name);
         let mut stmt = self.prepare(pragma)?;
+        let mut results = Vec::new();
         loop {
             match stmt.step()? {
                 vdbe::StepResult::Row => {
-                    let row = stmt.row().unwrap();
-                    f(row)?;
+                    let row: Vec<Value> = stmt
+                        .row()
+                        .unwrap()
+                        .get_values()
+                        .map(|v| v.clone())
+                        .collect();
+                    results.push(row);
+                }
+                vdbe::StepResult::Interrupt | vdbe::StepResult::Busy => {
+                    return Err(LimboError::Busy);
                 }
                 _ => break,
             }
         }
-        Ok(())
+
+        Ok(results)
     }
 }
 
@@ -681,6 +685,8 @@ impl Statement {
     }
 }
 
+pub type Row = vdbe::Row;
+
 pub type StepResult = vdbe::StepResult;
 
 #[derive(Clone, Debug)]