Extract RawStatement wrapper around *mut sqlite3_stmt.

src/lib.rs

@@ -76,6 +76,7 @@ use libc::{c_int, c_char};
 
 use types::{ToSql, FromSql};
 use error::{error_from_sqlite_code, error_from_handle};
+use raw_statement::RawStatement;
 
 pub use transaction::{SqliteTransaction, Transaction, TransactionBehavior};
 pub use error::{SqliteError, Error};
@@ -88,6 +89,7 @@ mod transaction;
 mod named_params;
 mod error;
 mod convenient;
+mod raw_statement;
 #[cfg(feature = "load_extension")]mod load_extension_guard;
 #[cfg(feature = "trace")]pub mod trace;
 #[cfg(feature = "backup")]pub mod backup;
@@ -687,7 +689,7 @@ impl InnerConnection {
                                     &mut c_stmt,
                                     ptr::null_mut())
         };
-        self.decode_result(r).map(|_| Statement::new(conn, c_stmt))
+        self.decode_result(r).map(|_| Statement::new(conn, RawStatement::new(c_stmt)))
     }
 
     fn changes(&mut self) -> c_int {
@@ -708,16 +710,17 @@ pub type SqliteStatement<'conn> = Statement<'conn>;
 /// A prepared statement.
 pub struct Statement<'conn> {
     conn: &'conn Connection,
-    stmt: *mut ffi::sqlite3_stmt,
+    stmt: RawStatement,
     column_count: c_int,
 }
 
 impl<'conn> Statement<'conn> {
-    fn new(conn: &Connection, stmt: *mut ffi::sqlite3_stmt) -> Statement {
+    fn new(conn: &Connection, stmt: RawStatement) -> Statement {
+        let column_count = stmt.column_count();
         Statement {
             conn: conn,
             stmt: stmt,
-            column_count: unsafe { ffi::sqlite3_column_count(stmt) },
+            column_count: column_count,
         }
     }
 
@@ -726,7 +729,7 @@ impl<'conn> Statement<'conn> {
         let n = self.column_count;
         let mut cols = Vec::with_capacity(n as usize);
         for i in 0..n {
-            let slice = unsafe { CStr::from_ptr(ffi::sqlite3_column_name(self.stmt, i)) };
+            let slice = self.stmt.column_name(i);
             let s = str::from_utf8(slice.to_bytes()).unwrap();
             cols.push(s);
         }
@@ -747,8 +750,7 @@ impl<'conn> Statement<'conn> {
         let bytes = name.as_bytes();
         let n = self.column_count;
         for i in 0..n {
-            let slice = unsafe { CStr::from_ptr(ffi::sqlite3_column_name(self.stmt, i)) };
-            if bytes == slice.to_bytes() {
+            if bytes == self.stmt.column_name(i).to_bytes() {
                 return Ok(i);
             }
         }
@@ -779,15 +781,13 @@ impl<'conn> Statement<'conn> {
     /// Will return `Err` if binding parameters fails, the executed statement returns rows (in
     /// which case `query` should be used instead), or the underling SQLite call fails.
     pub fn execute(&mut self, params: &[&ToSql]) -> Result<c_int> {
-        unsafe {
         try!(self.bind_parameters(params));
         self.execute_()
     }
-    }
 
-    unsafe fn execute_(&mut self) -> Result<c_int> {
-        let r = ffi::sqlite3_step(self.stmt);
-        ffi::sqlite3_reset(self.stmt);
+    fn execute_(&mut self) -> Result<c_int> {
+        let r = self.stmt.step();
+        self.stmt.reset();
         match r {
             ffi::SQLITE_DONE => {
                 if self.column_count == 0 {
@@ -825,10 +825,7 @@ impl<'conn> Statement<'conn> {
     ///
     /// Will return `Err` if binding parameters fails.
     pub fn query<'a>(&'a mut self, params: &[&ToSql]) -> Result<Rows<'a>> {
-        unsafe {
         try!(self.bind_parameters(params));
-        }
-
         Ok(Rows::new(self))
     }
 
@@ -889,14 +886,16 @@ impl<'conn> Statement<'conn> {
         self.finalize_()
     }
 
-    unsafe fn bind_parameters(&mut self, params: &[&ToSql]) -> Result<()> {
-        assert!(params.len() as c_int == ffi::sqlite3_bind_parameter_count(self.stmt),
+    fn bind_parameters(&mut self, params: &[&ToSql]) -> Result<()> {
+        assert!(params.len() as c_int == self.stmt.bind_parameter_count(),
                 "incorrect number of parameters to query(): expected {}, got {}",
-                ffi::sqlite3_bind_parameter_count(self.stmt),
+                self.stmt.bind_parameter_count(),
                 params.len());
 
         for (i, p) in params.iter().enumerate() {
-            try!(self.conn.decode_result(p.bind_parameter(self.stmt, (i + 1) as c_int)));
+            try!(unsafe {
+                self.conn.decode_result(p.bind_parameter(self.stmt.ptr(), (i + 1) as c_int))
+            });
         }
 
         Ok(())
@@ -904,32 +903,25 @@ impl<'conn> Statement<'conn> {
 
     #[cfg(feature = "cache")]
     fn clear_bindings(&mut self) {
-        unsafe {
-            ffi::sqlite3_clear_bindings(self.stmt);
-        };
+        self.stmt.clear_bindings();
     }
 
     #[cfg(feature = "cache")]
     fn eq(&self, sql: &str) -> bool {
-        unsafe {
-            let c_slice = CStr::from_ptr(ffi::sqlite3_sql(self.stmt)).to_bytes();
-            str::from_utf8(c_slice).unwrap().eq(sql)
-        }
+        let c_slice = self.stmt.sql().to_bytes();
+        sql.as_bytes().eq(c_slice)
     }
 
     fn finalize_(&mut self) -> Result<()> {
-        let r = unsafe { ffi::sqlite3_finalize(self.stmt) };
-        self.stmt = ptr::null_mut();
-        self.conn.decode_result(r)
+        let mut stmt = RawStatement::new(ptr::null_mut());
+        mem::swap(&mut stmt, &mut self.stmt);
+        self.conn.decode_result(stmt.finalize())
     }
 }
 
 impl<'conn> fmt::Debug for Statement<'conn> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        let sql = unsafe {
-            let c_slice = CStr::from_ptr(ffi::sqlite3_sql(self.stmt)).to_bytes();
-            str::from_utf8(c_slice)
-        };
+        let sql = str::from_utf8(self.stmt.sql().to_bytes());
         f.debug_struct("Statement")
             .field("conn", self.conn)
             .field("stmt", &self.stmt)
@@ -1039,9 +1031,7 @@ impl<'stmt> Rows<'stmt> {
 
     fn reset(&mut self) {
         if let Some(stmt) = self.stmt.take() {
-            unsafe {
-                ffi::sqlite3_reset(stmt.stmt);
-            }
+            stmt.stmt.reset();
         }
     }
 }
@@ -1051,7 +1041,7 @@ impl<'stmt> Iterator for Rows<'stmt> {
 
     fn next(&mut self) -> Option<Result<Row<'stmt>>> {
         self.stmt.and_then(|stmt| {
-            match unsafe { ffi::sqlite3_step(stmt.stmt) } {
+            match stmt.stmt.step() {
                 ffi::SQLITE_ROW => {
                     let current_row = self.current_row.get() + 1;
                     self.current_row.set(current_row);
@@ -1146,8 +1136,8 @@ impl<'stmt> Row<'stmt> {
         unsafe {
             let idx = try!(idx.idx(self.stmt));
 
-            if T::column_has_valid_sqlite_type(self.stmt.stmt, idx) {
-                FromSql::column_result(self.stmt.stmt, idx)
+            if T::column_has_valid_sqlite_type(self.stmt.stmt.ptr(), idx) {
+                FromSql::column_result(self.stmt.stmt.ptr(), idx)
             } else {
                 Err(Error::InvalidColumnType)
             }

src/named_params.rs

@@ -1,7 +1,5 @@
 use libc::c_int;
 
-use super::ffi;
-
 use {Result, Error, Connection, Statement, Rows, Row, str_to_cstring};
 use types::ToSql;
 
@@ -56,11 +54,7 @@ impl<'conn> Statement<'conn> {
     /// is valid but not a bound parameter of this statement.
     pub fn parameter_index(&self, name: &str) -> Result<Option<i32>> {
         let c_name = try!(str_to_cstring(name));
-        let c_index = unsafe { ffi::sqlite3_bind_parameter_index(self.stmt, c_name.as_ptr()) };
-        Ok(match c_index {
-            0 => None, // A zero is returned if no matching parameter is found.
-            n => Some(n),
-        })
+        Ok(self.stmt.bind_parameter_index(&c_name))
     }
 
     /// Execute the prepared statement with named parameter(s). If any parameters
@@ -87,7 +81,7 @@ impl<'conn> Statement<'conn> {
     /// which case `query` should be used instead), or the underling SQLite call fails.
     pub fn execute_named(&mut self, params: &[(&str, &ToSql)]) -> Result<c_int> {
         try!(self.bind_parameters_named(params));
-        unsafe { self.execute_() }
+        self.execute_()
     }
 
     /// Execute the prepared statement with named parameter(s), returning an iterator over the
@@ -120,7 +114,7 @@ impl<'conn> Statement<'conn> {
     fn bind_parameters_named(&mut self, params: &[(&str, &ToSql)]) -> Result<()> {
         for &(name, value) in params {
             if let Some(i) = try!(self.parameter_index(name)) {
-                try!(self.conn.decode_result(unsafe { value.bind_parameter(self.stmt, i) }));
+                try!(self.conn.decode_result(unsafe { value.bind_parameter(self.stmt.ptr(), i) }));
             } else {
                 return Err(Error::InvalidParameterName(name.into()));
             }

src/raw_statement.rs

@@ -0,0 +1,71 @@
+use std::ffi::CStr;
+use std::ptr;
+use libc::c_int;
+use super::ffi;
+
+// Private newtype for raw sqlite3_stmts that finalize themselves when dropped.
+#[derive(Debug)]
+pub struct RawStatement(*mut ffi::sqlite3_stmt);
+
+impl RawStatement {
+    pub fn new(stmt: *mut ffi::sqlite3_stmt) -> RawStatement {
+        RawStatement(stmt)
+    }
+
+    pub unsafe fn ptr(&self) -> *mut ffi::sqlite3_stmt {
+        self.0
+    }
+
+    pub fn column_count(&self) -> c_int {
+        unsafe { ffi::sqlite3_column_count(self.0) }
+    }
+
+    pub fn column_name(&self, idx: c_int) -> &CStr {
+        unsafe { CStr::from_ptr(ffi::sqlite3_column_name(self.0, idx)) }
+    }
+
+    pub fn step(&self) -> c_int {
+        unsafe { ffi::sqlite3_step(self.0) }
+    }
+
+    pub fn reset(&self) -> c_int {
+        unsafe { ffi::sqlite3_reset(self.0) }
+    }
+
+    pub fn bind_parameter_count(&self) -> c_int {
+        unsafe { ffi::sqlite3_bind_parameter_count(self.0) }
+    }
+
+    pub fn bind_parameter_index(&self, name: &CStr) -> Option<c_int> {
+        let r = unsafe { ffi::sqlite3_bind_parameter_index(self.0, name.as_ptr()) };
+        match r {
+            0 => None,
+            i => Some(i),
+        }
+    }
+
+    #[cfg(feature = "cache")]
+    pub fn clear_bindings(&self) -> c_int {
+        unsafe { ffi::sqlite3_clear_bindings(self.0) }
+    }
+
+    pub fn sql(&self) -> &CStr {
+        unsafe { CStr::from_ptr(ffi::sqlite3_sql(self.0)) }
+    }
+
+    pub fn finalize(mut self) -> c_int {
+        self.finalize_()
+    }
+
+    fn finalize_(&mut self) -> c_int {
+        let r = unsafe { ffi::sqlite3_finalize(self.0) };
+        self.0 = ptr::null_mut();
+        r
+    }
+}
+
+impl Drop for RawStatement {
+    fn drop(&mut self) {
+        self.finalize_();
+    }
+}