/*****************************************************************************
  
  Zope Public License (ZPL) Version 1.0
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  This software consists of contributions made by Digital Creations and
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 ****************************************************************************/

#ifndef CPERSISTENCE_H
#define CPERSISTENCE_H

#include "ExtensionClass.h"
#include <time.h>
#include <stddef.h>

/* Persistent objects have a reference to their jar, the jar has a reference to the cache, and
   the cache has a reference to all the objects. Objects also have pointers to the ring part
   of the other objects and their cache.

   All of these links should always be right, however we do allow the object->jar link to stray.

   It is a strong invariant that all other links are consistent.
*/



#define cPersistent_HEAD PyObject_HEAD PyObject *jar, *oid, *cache; CPersistentRing ring; char serial[8]; signed char state; unsigned char reserved[3];
#define cPersistent_GHOST_STATE -1
#define cPersistent_UPTODATE_STATE 0
#define cPersistent_CHANGED_STATE 1
#define cPersistent_STICKY_STATE 2

struct ccobject_head_struct;

typedef struct CPersistentRing_struct
{
    struct CPersistentRing_struct *prev;
    struct CPersistentRing_struct *next;
} CPersistentRing;

typedef struct {
  cPersistent_HEAD
} cPersistentObject;

typedef int (*persetattr)(PyObject *, PyObject*, PyObject *, setattrofunc);
typedef PyObject *(*pergetattr)(PyObject *, PyObject*, char *, getattrofunc);

typedef struct {
  PyMethodChain *methods;
  getattrofunc getattro;
  setattrofunc setattro;
  int (*changed)(cPersistentObject*);
  void (*accessed)(cPersistentObject*);
  void (*ghostify)(cPersistentObject*);
  int (*setstate)(PyObject*);
  pergetattr pergetattro;
  persetattr persetattro;
} cPersistenceCAPIstruct;

#ifndef DONT_USE_CPERSISTENCECAPI
static cPersistenceCAPIstruct *cPersistenceCAPI;
#endif

#define cPersistanceModuleName "cPersistence"

#define PERSISTENT_TYPE_FLAG EXTENSIONCLASS_USER_FLAG8

/* ExtensionClass class flags for persistent base classes should
   include PERSISTENCE_FLAGS. 
*/
#define PERSISTENCE_FLAGS EXTENSIONCLASS_BASICNEW_FLAG | PERSISTENT_TYPE_FLAG \
  | EXTENSIONCLASS_PYTHONICATTR_FLAG

#define PER_USE_OR_RETURN(O,R) {if((O)->state==cPersistent_GHOST_STATE && cPersistenceCAPI->setstate((PyObject*)(O)) < 0) return (R); else if ((O)->state==cPersistent_UPTODATE_STATE) (O)->state=cPersistent_STICKY_STATE;}

#define PER_CHANGED(O) (cPersistenceCAPI->changed((cPersistentObject*)(O)))

#define PER_GHOSTIFY(O) (cPersistenceCAPI->ghostify((cPersistentObject*)(O)))

#define PER_ALLOW_DEACTIVATION(O) ((O)->state==cPersistent_STICKY_STATE && ((O)->state=cPersistent_UPTODATE_STATE))

#define PER_PREVENT_DEACTIVATION(O)  ((O)->state==cPersistent_UPTODATE_STATE && ((O)->state=cPersistent_STICKY_STATE)) 

#define PER_DEL(O) Py_XDECREF((O)->jar); Py_XDECREF((O)->oid);

#define PER_USE(O) \
(((O)->state != cPersistent_GHOST_STATE \
  || (cPersistenceCAPI->setstate((PyObject*)(O)) >= 0)) \
 ? (((O)->state==cPersistent_UPTODATE_STATE) \
    ? ((O)->state=cPersistent_STICKY_STATE) : 1) : 0)

#define PER_ACCESSED(O)  (cPersistenceCAPI->accessed((cPersistentObject*)(O)))

#endif