Line data    Source code

       1             : /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
       2             :  * vim: set ts=8 sts=4 et sw=4 tw=99:
       3             :  * This Source Code Form is subject to the terms of the Mozilla Public
       4             :  * License, v. 2.0. If a copy of the MPL was not distributed with this
       5             :  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
       6             : 
       7             : #ifndef vm_StringObject_h
       8             : #define vm_StringObject_h
       9             : 
      10             : #include "jsobj.h"
      11             : #include "jsstr.h"
      12             : 
      13             : #include "vm/Shape.h"
      14             : 
      15             : namespace js {
      16             : 
      17             : class StringObject : public NativeObject
      18             : {
      19             :     static const unsigned PRIMITIVE_VALUE_SLOT = 0;
      20             :     static const unsigned LENGTH_SLOT = 1;
      21             : 
      22             :   public:
      23             :     static const unsigned RESERVED_SLOTS = 2;
      24             : 
      25             :     static const Class class_;
      26             : 
      27             :     /*
      28             :      * Creates a new String object boxing the given string.  The object's
      29             :      * [[Prototype]] is determined from context.
      30             :      */
      31             :     static inline StringObject* create(JSContext* cx, HandleString str,
      32             :                                        HandleObject proto = nullptr,
      33             :                                        NewObjectKind newKind = GenericObject);
      34             : 
      35             :     /*
      36             :      * Compute the initial shape to associate with fresh String objects, which
      37             :      * encodes the initial length property. Return the shape after changing
      38             :      * |obj|'s last property to it.
      39             :      */
      40             :     static Shape*
      41             :     assignInitialShape(JSContext* cx, Handle<StringObject*> obj);
      42             : 
      43           2 :     JSString* unbox() const {
      44           2 :         return getFixedSlot(PRIMITIVE_VALUE_SLOT).toString();
      45             :     }
      46             : 
      47             :     inline size_t length() const {
      48             :         return size_t(getFixedSlot(LENGTH_SLOT).toInt32());
      49             :     }
      50             : 
      51           0 :     static size_t offsetOfPrimitiveValue() {
      52           0 :         return getFixedSlotOffset(PRIMITIVE_VALUE_SLOT);
      53             :     }
      54           0 :     static size_t offsetOfLength() {
      55           0 :         return getFixedSlotOffset(LENGTH_SLOT);
      56             :     }
      57             : 
      58             :   private:
      59             :     static inline bool init(JSContext* cx, Handle<StringObject*> obj, HandleString str);
      60             : 
      61          49 :     void setStringThis(JSString* str) {
      62          49 :         MOZ_ASSERT(getReservedSlot(PRIMITIVE_VALUE_SLOT).isUndefined());
      63          49 :         setFixedSlot(PRIMITIVE_VALUE_SLOT, StringValue(str));
      64          49 :         setFixedSlot(LENGTH_SLOT, Int32Value(int32_t(str->length())));
      65          49 :     }
      66             : 
      67             :     /* For access to init, as String.prototype is special. */
      68             :     friend JSObject*
      69             :     js::InitStringClass(JSContext* cx, HandleObject global);
      70             : };
      71             : 
      72             : } // namespace js
      73             : 
      74             : #endif /* vm_StringObject_h */