1 files changed, 74 insertions, 0 deletions
diff --git a/js/src/vm/StringObject.h b/js/src/vm/StringObject.h
new file mode 100644
index 000000000..119e3d9fa
--- /dev/null
+++ b/js/src/vm/StringObject.h
@@ -0,0 +1,74 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
+ * vim: set ts=8 sts=4 et sw=4 tw=99:
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef vm_StringObject_h
+#define vm_StringObject_h
+
+#include "jsobj.h"
+#include "jsstr.h"
+
+#include "vm/Shape.h"
+
+namespace js {
+
+class StringObject : public NativeObject
+{
+    static const unsigned PRIMITIVE_VALUE_SLOT = 0;
+    static const unsigned LENGTH_SLOT = 1;
+
+  public:
+    static const unsigned RESERVED_SLOTS = 2;
+
+    static const Class class_;
+
+    /*
+     * Creates a new String object boxing the given string.  The object's
+     * [[Prototype]] is determined from context.
+     */
+    static inline StringObject* create(JSContext* cx, HandleString str,
+                                       HandleObject proto = nullptr,
+                                       NewObjectKind newKind = GenericObject);
+
+    /*
+     * Compute the initial shape to associate with fresh String objects, which
+     * encodes the initial length property. Return the shape after changing
+     * |obj|'s last property to it.
+     */
+    static Shape*
+    assignInitialShape(ExclusiveContext* cx, Handle<StringObject*> obj);
+
+    JSString* unbox() const {
+        return getFixedSlot(PRIMITIVE_VALUE_SLOT).toString();
+    }
+
+    inline size_t length() const {
+        return size_t(getFixedSlot(LENGTH_SLOT).toInt32());
+    }
+
+    static size_t offsetOfPrimitiveValue() {
+        return getFixedSlotOffset(PRIMITIVE_VALUE_SLOT);
+    }
+    static size_t offsetOfLength() {
+        return getFixedSlotOffset(LENGTH_SLOT);
+    }
+
+  private:
+    inline bool init(JSContext* cx, HandleString str);
+
+    void setStringThis(JSString* str) {
+        MOZ_ASSERT(getReservedSlot(PRIMITIVE_VALUE_SLOT).isUndefined());
+        setFixedSlot(PRIMITIVE_VALUE_SLOT, StringValue(str));
+        setFixedSlot(LENGTH_SLOT, Int32Value(int32_t(str->length())));
+    }
+
+    /* For access to init, as String.prototype is special. */
+    friend JSObject*
+    js::InitStringClass(JSContext* cx, HandleObject global);
+};
+
+} // namespace js
+
+#endif /* vm_StringObject_h */