convert header to thread safety

header.go

@@ -30,7 +30,7 @@ func (ctx *Context) SetHeaders(opts libs.SassOptions) {
 		}
 	}
 	// ctx.entries = &entries
-	libs.BindHeader(opts, &entries)
+	libs.BindHeader(opts, entries)
 }
 
 type Header struct {

libs/header.go

@@ -15,16 +15,20 @@ package libs
 // }
 //
 import "C"
-import (
-	"runtime"
-	"unsafe"
-)
+import "unsafe"
+
+var globalHeaders SafeMap
+
+func init() {
+	globalHeaders.init()
+}
 
 // This binds the header to the libsass header lookup
-func BindHeader(opts SassOptions, entries *[]ImportEntry) {
-	ptr := unsafe.Pointer(entries)
-	// FIXME: this should be cleaned up manually later
-	runtime.SetFinalizer(entries, nil)
+func BindHeader(opts SassOptions, entries []ImportEntry) {
+
+	idx := globalHeaders.set(entries)
+	ptr := unsafe.Pointer(idx)
+
 	imper := C.sass_make_importer(
 		C.Sass_Importer_Fn(C.SassHeaders),
 		C.double(0),

libs/wrap.go

@@ -37,7 +37,12 @@ type ImportEntry struct {
 
 //export HeaderBridge
 func HeaderBridge(ptr unsafe.Pointer) C.Sass_Import_List {
-	entries := *(*[]ImportEntry)(ptr)
+	idx := (*string)(ptr)
+	entries, ok := globalHeaders.get(idx).([]ImportEntry)
+	if !ok {
+		fmt.Printf("failed to resolve header slice: %p\n", ptr)
+		return C.sass_make_import_list(C.size_t(1))
+	}
 
 	cents := C.sass_make_import_list(C.size_t(len(entries)))