Introduce VTab and VTabCursor traits.

src/vtab/csvtab.rs

@@ -7,7 +7,7 @@ use libc;
 use {Connection, Error, Result};
 use ffi;
 use types::Null;
-use vtab::declare_vtab;
+use vtab::{declare_vtab, VTab, VTabCursor};
 
 use self::csv::Reader;
 
@@ -31,7 +31,7 @@ struct CSVTab {
     cols: Vec<String>,
 }
 
-impl CSVTab {
+impl VTab<CSVTabCursor> for CSVTab {
     fn create(db: *mut ffi::sqlite3,
               aux: *mut libc::c_void,
               argc: libc::c_int,
@@ -76,7 +76,9 @@ impl CSVTabCursor {
             row_number: 0,
         }
     }
+}
 
+impl VTabCursor<CSVTab> for CSVTabCursor {
     fn vtab(&self) -> &mut CSVTab {
         unsafe { &mut *(self.base.pVtab as *mut CSVTab) }
     }

src/vtab/int_array.rs

@@ -7,7 +7,7 @@ use libc;
 
 use {Connection, Error, Result};
 use ffi;
-use vtab::declare_vtab;
+use vtab::{declare_vtab, VTab, VTabCursor};
 
 pub fn create_int_array(conn: &Connection, name: &str) -> Result<Rc<RefCell<Vec<i64>>>> {
     let array = Rc::new(RefCell::new(Vec::new()));
@@ -24,7 +24,7 @@ pub fn drop_int_array(conn: &Connection, name: &str) -> Result<()> {
 fn escape_quote(identifier: String) -> String {
     if identifier.contains('"') {
         // escape quote by doubling them
-        identifier.replace('"', "\"\"")
+        identifier.replace("\"", "\"\"")
     } else {
         identifier
     }
@@ -43,7 +43,7 @@ struct IntArrayVTab {
     array: *const Rc<RefCell<Vec<i64>>>,
 }
 
-impl IntArrayVTab {
+impl VTab<IntArrayVTabCursor> for IntArrayVTab {
     fn create(db: *mut ffi::sqlite3,
               aux: *mut libc::c_void,
               _argc: libc::c_int,
@@ -80,11 +80,12 @@ impl IntArrayVTabCursor {
             i: 0,
         }
     }
+}
 
+impl VTabCursor<IntArrayVTab> for IntArrayVTabCursor {
     fn vtab(&self) -> &mut IntArrayVTab {
         unsafe { &mut *(self.base.pVtab as *mut IntArrayVTab) }
     }
-
     fn filter(&mut self) -> Result<()> {
         self.i = 0;
         Ok(())

src/vtab/mod.rs

@@ -37,6 +37,25 @@ use ffi;
 //  \-> if not eof { cursor.column or xrowid } else { cursor.xclose }
 //
 
+pub trait VTab<C: VTabCursor<Self>>: Sized {
+    fn create(db: *mut ffi::sqlite3,
+              aux: *mut libc::c_void,
+              _argc: libc::c_int,
+              _argv: *const *const libc::c_char)
+              -> Result<Self>;
+    fn best_index(&self, _info: *mut ffi::sqlite3_index_info);
+    fn open(&self) -> Result<C>;
+}
+
+pub trait VTabCursor<V: VTab<Self>>: Sized {
+    fn vtab(&self) -> &mut V;
+    fn filter(&mut self) -> Result<()>;
+    fn next(&mut self) -> Result<()>;
+    fn eof(&self) -> bool;
+    fn column(&self, ctx: *mut ffi::sqlite3_context, _i: libc::c_int) -> Result<()>;
+    fn rowid(&self) -> Result<i64>;
+}
+
 impl Connection {
     /// Register a virtual table implementation.
     pub fn create_module<A>(&self,
@@ -261,7 +280,7 @@ pub unsafe fn cursor_error<T>(cursor: *mut ffi::sqlite3_vtab_cursor,
     }
 }
 
-unsafe fn set_err_msg(vtab: *mut ffi::sqlite3_vtab, err_msg: &str) {
+pub unsafe fn set_err_msg(vtab: *mut ffi::sqlite3_vtab, err_msg: &str) {
     if !(*vtab).zErrMsg.is_null() {
         ffi::sqlite3_free((*vtab).zErrMsg as *mut libc::c_void);
     }