introduce ability to pass sqlite_omit_load_extension

sqlite_omit_load_extension is a go build tag which behaves much like its
C counterpart SQLITE_OMIT_LOAD_EXTENSION

Signed-off-by: Jessica Frazelle <acidburn@docker.com>

sqlite3.go

@@ -355,23 +355,8 @@ func (d *SQLiteDriver) Open(dsn string) (driver.Conn, error) {
 	conn := &SQLiteConn{db: db, loc: loc, txlock: txlock}
 
 	if len(d.Extensions) > 0 {
-		rv = C.sqlite3_enable_load_extension(db, 1)
-		if rv != C.SQLITE_OK {
-			return nil, errors.New(C.GoString(C.sqlite3_errmsg(db)))
-		}
-
-		for _, extension := range d.Extensions {
-			cext := C.CString(extension)
-			defer C.free(unsafe.Pointer(cext))
-			rv = C.sqlite3_load_extension(db, cext, nil, nil)
-			if rv != C.SQLITE_OK {
-				return nil, errors.New(C.GoString(C.sqlite3_errmsg(db)))
-			}
-		}
-
-		rv = C.sqlite3_enable_load_extension(db, 0)
-		if rv != C.SQLITE_OK {
-			return nil, errors.New(C.GoString(C.sqlite3_errmsg(db)))
+		if err := conn.loadExtensions(d.Extensions); err != nil {
+			return nil, err
 		}
 	}
 

sqlite3_load_extension.go

@@ -0,0 +1,39 @@
+// Copyright (C) 2014 Yasuhiro Matsumoto <mattn.jp@gmail.com>.
+//
+// Use of this source code is governed by an MIT-style
+// license that can be found in the LICENSE file.
+// +build !sqlite_omit_load_extension
+
+package sqlite3
+
+/*
+#include <sqlite3-binding.h>
+#include <stdlib.h>
+*/
+import "C"
+import (
+	"errors"
+	"unsafe"
+)
+
+func (c *SQLiteConn) loadExtensions(extensions []string) error {
+	rv := C.sqlite3_enable_load_extension(c.db, 1)
+	if rv != C.SQLITE_OK {
+		return errors.New(C.GoString(C.sqlite3_errmsg(c.db)))
+	}
+
+	for _, extension := range extensions {
+		cext := C.CString(extension)
+		defer C.free(unsafe.Pointer(cext))
+		rv = C.sqlite3_load_extension(c.db, cext, nil, nil)
+		if rv != C.SQLITE_OK {
+			return errors.New(C.GoString(C.sqlite3_errmsg(c.db)))
+		}
+	}
+
+	rv = C.sqlite3_enable_load_extension(c.db, 0)
+	if rv != C.SQLITE_OK {
+		return errors.New(C.GoString(C.sqlite3_errmsg(c.db)))
+	}
+	return nil
+}

sqlite3_omit_load_extension.go

@@ -0,0 +1,19 @@
+// Copyright (C) 2014 Yasuhiro Matsumoto <mattn.jp@gmail.com>.
+//
+// Use of this source code is governed by an MIT-style
+// license that can be found in the LICENSE file.
+// +build sqlite_omit_load_extension
+
+package sqlite3
+
+/*
+#cgo CFLAGS: -DSQLITE_OMIT_LOAD_EXTENSION
+*/
+import "C"
+import (
+	"errors"
+)
+
+func (c *SQLiteConn) loadExtensions(extensions []string) error {
+	return errors.New("Extensions have been disabled for static builds")
+}