// SassMakeFunction binds a Go pointer to a Sass function signature
func SassMakeFunction(signature string, ptr unsafe.Pointer) SassFunc {
csign := C.CString(signature)
fn := C.sass_make_function(
csign,
C.Sass_Function_Fn(C.CallSassFunction),
ptr)
return (SassFunc)(fn)
}
func (ctx *Context) SetFunc(opts *C.struct_Sass_Options) {
cookies := make([]Cookie, len(handlers)+len(ctx.Cookies))
// Append registered handlers to cookie array
for i, h := range handlers {
cookies[i] = Cookie{
h.sign, h.callback, ctx,
}
}
for i, h := range ctx.Cookies {
cookies[i+len(handlers)] = Cookie{
h.Sign, h.Fn, ctx,
}
}
ctx.Cookies = cookies
size := C.size_t(len(ctx.Cookies))
fns := C.sass_make_function_list(size)
// Send cookies to libsass
// Create a slice that's backed by a C array
length := len(ctx.Cookies) + 1
hdr := reflect.SliceHeader{
Data: uintptr(unsafe.Pointer(fns)),
Len: length, Cap: length,
}
gofns := *(*[]C.Sass_Function_Entry)(unsafe.Pointer(&hdr))
for i, cookie := range ctx.Cookies {
sign := C.CString(cookie.Sign)
fn := C.sass_make_function(
// sass signature
sign,
// C bridge
C.Sass_Function_Fn(C.CallSassFunction),
// Only pass reference to global array, so
// GC won't clean it up.
unsafe.Pointer(&ctx.Cookies[i]))
gofns[i] = fn
}
C.sass_option_set_c_functions(opts, (C.Sass_Function_List)(unsafe.Pointer(&gofns[0])))
}