/* vim: set ts=4 sw=4 tw=99 et:

  *

  * Copyright (C) 2012 David Anderson

  *

  * This file is part of JITCraft.

  *

  * JITCraft is free software: you can redistribute it and/or modify it under

  * the terms of the GNU General Public License as published by the Free

  * Software Foundation, either version 3 of the License, or (at your option)

  * any later version.

  * 

  * Foobar is distributed in the hope that it will be useful, but WITHOUT ANY

  * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS

  * FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

  *

  * You should have received a copy of the GNU General Public License along with

  * JITCraft. If not, see http://www.gnu.org/licenses/.

  */

 #ifndef _include_jitcraft_objects_h_

 #define _include_jitcraft_objects_h_

 #include "Utility.h"

 #include "Spaces.h"

 #include "Barriers.h"

 namespace ke {

 class Zone;

 // Garbage-collection objects require a header to describe their layout. This

 // header is called a "map". The different kinds of maps are enumerated below.

 class Map;

 enum MapKind

 {

     // Represents Type objects.

     MapKind_Type,

     // Represents basic data structures. When adding to this, don't forget

     // to update Zone::initialize(), or you'll get a NULL crash trying to

     // allocate, since these maps are cached.

     MapKind_FixedArray,

     MapKind_ByteArray,

     MapKind_Code,

     MapKind_Reference,

     MapKind_Module,

     MapKind_Function,

     MapKind_String,

     MapKind_Native,

     MapKind_FreeRegion,     // Special map denoting freed space.

     MapKind_EnvironmentSlotDescriptorArray,

     MapKind_Environment,

     MapKind_Descriptor,

     // These do not have canonical maps.

     MapKind_Array,

     MapKind_Struct,

     // These represent special Map subclasses that require special tracing.

     MapKinds_Special,

     MapKind_Meta,               // (default map class)

     MapKind_MetaArray,          // ArrayMap instances

     MapKind_MetaEnvironment,    // EnvironmentMap instances

     MapKind_MetaStruct,         // StructMap instances

     MapKinds_EndSpecial,

     MapKinds_Total

 };

 // All garbage collected objects must inherit from GCObject. Note that using

 // virtual functions is illegal, as the |map| field would be displaced.

 class Object

 {

     Barriered<Map> map_;

   public:

     void init(Map *map) {

         map_ = map;

     }

     Map *map() {

         return map_;

     }

     inline bool is(MapKind map);

     inline void write(Zone *zone, Object **ptr, Object *value);

     static inline size_t offsetOfMap() {

         // Clang doesn't accept offsetof here and it's not clear why...

         return reinterpret_cast<size_t>(&((Object *)NULL)->map_);

     }

 };

 // Maps describe the layout of GCObjects. Every GCObject requires a map.

 class Map : public Object

 {

     MapKind kind_;

   public:

     void setKind(MapKind kind) {

         kind_ = kind;

     }

     MapKind kind() {

         return kind_;

     }

     static inline Map *cast(Object *obj) {

         // Note that ArrayMap is a map, but a special one: since it is non-

         assert(obj->map()->kind() > MapKinds_Special &&

                obj->map()->kind() < MapKinds_EndSpecial);

         return reinterpret_cast<Map *>(obj);

     }

 };

 inline bool

 Object::is(MapKind kind)

 {

     return map()->kind() == kind;

 }

 }

 #endif //_include_jitcraft_objects_h_