Support $NNN-style named parameter. Close #187

2 files changed, 93 insertions, 4 deletions

diff --git a/sqlite3.go b/sqlite3.go
index 91aea8f..4e68e96 100644
--- a/sqlite3.go
+++ b/sqlite3.go
@@ -121,6 +121,7 @@ type SQLiteTx struct {
 type SQLiteStmt struct {
 	c      *SQLiteConn
 	s      *C.sqlite3_stmt
+	nv     int
 	t      string
 	closed bool
 	cls    bool
@@ -368,7 +369,19 @@ func (c *SQLiteConn) Prepare(query string) (driver.Stmt, error) {
 	if tail != nil && C.strlen(tail) > 0 {
 		t = strings.TrimSpace(C.GoString(tail))
 	}
-	ss := &SQLiteStmt{c: c, s: s, t: t}
+	nv := int(C.sqlite3_bind_parameter_count(s))
+	if nv > 0 {
+		pn := C.GoString(C.sqlite3_bind_parameter_name(s, 1))
+		/* TODO: map argument for named parameters
+		if len(pn) > 0 && pn[0] == '$' && pn[1] != '1' {
+			nv = -1
+		}
+		*/
+		if len(pn) > 0 && pn[0] != '?' {
+			nv = -1
+		}
+	}
+	ss := &SQLiteStmt{c: c, s: s, nv: nv, t: t}
 	runtime.SetFinalizer(ss, (*SQLiteStmt).Close)
 	return ss, nil
 }
@@ -392,7 +405,12 @@ func (s *SQLiteStmt) Close() error {
 
 // Return a number of parameters.
 func (s *SQLiteStmt) NumInput() int {
-	return int(C.sqlite3_bind_parameter_count(s.s))
+	return s.nv
+}
+
+type bindArg struct {
+	n int
+	v driver.Value
 }
 
 func (s *SQLiteStmt) bind(args []driver.Value) error {
@@ -401,8 +419,43 @@ func (s *SQLiteStmt) bind(args []driver.Value) error {
 		return s.c.lastError()
 	}
 
-	for i, v := range args {
-		n := C.int(i + 1)
+	var vargs []bindArg
+	narg := len(args)
+	if s.nv == -1 {
+		/* TODO: map argument for named parameters
+		if narg == 1 {
+			if m, ok := args[0].(map[string]driver.Value); ok {
+				for k, v := range m {
+					pn := C.CString(k)
+					if pi := int(C.sqlite3_bind_parameter_index(s.s, pn)); pi > 0 {
+						println(pi)
+						vargs = append(vargs, bindArg{pi, v})
+					}
+					C.free(unsafe.Pointer(pn))
+				}
+			}
+			narg = 0
+		}
+		*/
+		if narg > 0 {
+			for i := 0; i < narg; i++ {
+				pn := C.CString(fmt.Sprint(i + 1))
+				if pi := int(C.sqlite3_bind_parameter_index(s.s, pn)); pi > 0 {
+					vargs = append(vargs, bindArg{pi, args[i]})
+				}
+				C.free(unsafe.Pointer(pn))
+			}
+		}
+	} else {
+		vargs = make([]bindArg, narg)
+		for i, v := range args {
+			vargs[i] = bindArg{i + 1, v}
+		}
+	}
+
+	for _, varg := range vargs {
+		n := C.int(varg.n)
+		v := varg.v
 		switch v := v.(type) {
 		case nil:
 			rv = C.sqlite3_bind_null(s.s, n)
diff --git a/sqlite3_test.go b/sqlite3_test.go
index 6570b52..245f363 100644
--- a/sqlite3_test.go
+++ b/sqlite3_test.go
@@ -909,3 +909,39 @@ func TestVersion(t *testing.T) {
 		t.Errorf("Version failed %q, %d, %q\n", s, n, id)
 	}
 }
+
+func TestNumberNamedParams(t *testing.T) {
+	tempFilename := TempFilename()
+	db, err := sql.Open("sqlite3", tempFilename)
+	if err != nil {
+		t.Fatal("Failed to open database:", err)
+	}
+	defer os.Remove(tempFilename)
+	defer db.Close()
+
+	_, err = db.Exec(`
+	create table foo (id integer, name text, extra text);
+	`)
+	if err != nil {
+		t.Error("Failed to call db.Query:", err)
+	}
+
+	_, err = db.Exec(`insert into foo(id, name, extra)) values($1, $2, $2)`, 1, "foo")
+	if err != nil {
+		t.Error("Failed to call db.Exec:", err)
+	}
+
+	row := db.QueryRow(`select id, name, extra where id = $1 and extra = $2`, 1, "foo")
+	if row == nil {
+		t.Error("Failed to call db.QueryRow")
+	}
+	var id int
+	var extra string
+	err = row.Scan(&id, &extra)
+	if err != nil {
+		t.Error("Failed to db.Scan:", err)
+	}
+	if id != 1 || extra != "foo" {
+		t.Error("Failed to db.QueryRow: not matched results")
+	}
+}