Reset in Rows's drop impl instead of waiting for the next query

src/convenient.rs

@@ -23,16 +23,14 @@ impl<'conn> Statement<'conn> {
     /// Return `true` if a query in the SQL statement it executes returns one or more rows
     /// and `false` if the SQL returns an empty set.
     pub fn exists(&mut self, params: &[&ToSql]) -> Result<bool> {
-        self.reset_if_needed();
-        let exists = {
         let mut rows = try!(self.query(params));
+        let exists = {
             match rows.next() {
-                Some(_) => Ok(true),
-                None => Ok(false),
+                Some(_) => true,
+                None => false,
             }
         };
-        self.reset_if_needed();
-        return exists;
+        Ok(exists)
     }
 }
 

src/lib.rs

@@ -708,7 +708,6 @@ pub type SqliteStatement<'conn> = Statement<'conn>;
 pub struct Statement<'conn> {
     conn: &'conn Connection,
     stmt: *mut ffi::sqlite3_stmt,
-    needs_reset: bool,
     column_count: c_int,
 }
 
@@ -717,7 +716,6 @@ impl<'conn> Statement<'conn> {
         Statement {
             conn: conn,
             stmt: stmt,
-            needs_reset: false,
             column_count: unsafe { ffi::sqlite3_column_count(stmt) },
         }
     }
@@ -826,13 +824,10 @@ impl<'conn> Statement<'conn> {
     ///
     /// Will return `Err` if binding parameters fails.
     pub fn query<'a>(&'a mut self, params: &[&ToSql]) -> Result<Rows<'a>> {
-        self.reset_if_needed();
-
         unsafe {
             try!(self.bind_parameters(params));
         }
 
-        self.needs_reset = true;
         Ok(Rows::new(self))
     }
 
@@ -906,15 +901,6 @@ impl<'conn> Statement<'conn> {
         Ok(())
     }
 
-    fn reset_if_needed(&mut self) {
-        if self.needs_reset {
-            unsafe {
-                ffi::sqlite3_reset(self.stmt);
-            };
-            self.needs_reset = false;
-        }
-    }
-
     fn finalize_(&mut self) -> Result<()> {
         let r = unsafe { ffi::sqlite3_finalize(self.stmt) };
         self.stmt = ptr::null_mut();
@@ -1064,6 +1050,14 @@ impl<'stmt> Iterator for Rows<'stmt> {
     }
 }
 
+impl<'stmt> Drop for Rows<'stmt> {
+    fn drop(&mut self) {
+        unsafe {
+            ffi::sqlite3_reset(self.stmt.stmt);
+        }
+    }
+}
+
 /// Old name for `Row`. `SqliteRow` is deprecated.
 pub type SqliteRow<'stmt> = Row<'stmt>;
 

src/named_params.rs

@@ -113,10 +113,7 @@ impl<'conn> Statement<'conn> {
     ///
     /// Will return `Err` if binding parameters fails.
     pub fn query_named<'a>(&'a mut self, params: &[(&str, &ToSql)]) -> Result<Rows<'a>> {
-        self.reset_if_needed();
         try!(self.bind_parameters_named(params));
-
-        self.needs_reset = true;
         Ok(Rows::new(self))
     }
 

src/trace.rs

@@ -4,7 +4,6 @@ use libc::{c_char, c_int, c_void};
 use std::ffi::{CStr, CString};
 use std::mem;
 use std::ptr;
-use std::str;
 use std::time::Duration;
 
 use super::ffi;