/*

 * Copyright © 2007  Chris Wilson

 * Copyright © 2009,2010  Red Hat, Inc.

 * Copyright © 2011,2012  Google, Inc.

 *

 *  This is part of HarfBuzz, a text shaping library.

 *

 * Permission is hereby granted, without written agreement and without

 * license or royalty fees, to use, copy, modify, and distribute this

 * software and its documentation for any purpose, provided that the

 * above copyright notice and the following two paragraphs appear in

 * all copies of this software.

 *

 * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR

 * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES

 * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN

 * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH

 * DAMAGE.

 *

 * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,

 * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND

 * FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS

 * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO

 * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.

 *

 * Contributor(s):

 *	Chris Wilson <chris@chris-wilson.co.uk>

 * Red Hat Author(s): Behdad Esfahbod

 * Google Author(s): Behdad Esfahbod

 */

#ifndef HB_OBJECT_PRIVATE_HH

#define HB_OBJECT_PRIVATE_HH

#include "hb-private.hh"

#include "hb-atomic-private.hh"

#include "hb-mutex-private.hh"

/* Debug */

#ifndef HB_DEBUG_OBJECT

#define HB_DEBUG_OBJECT (HB_DEBUG+0)

#endif

/* reference_count */

#define HB_REFERENCE_COUNT_INERT_VALUE -1

#define HB_REFERENCE_COUNT_POISON_VALUE -0x0000DEAD

#define HB_REFERENCE_COUNT_INIT {HB_ATOMIC_INT_INIT(HB_REFERENCE_COUNT_INERT_VALUE)}

struct hb_reference_count_t

{

  hb_atomic_int_t ref_count;

  inline void init (int v) { ref_count.set_unsafe (v); }

  inline int get_unsafe (void) const { return ref_count.get_unsafe (); }

  inline int inc (void) { return ref_count.inc (); }

  inline int dec (void) { return ref_count.dec (); }

  inline void finish (void) { ref_count.set_unsafe (HB_REFERENCE_COUNT_POISON_VALUE); }

  inline bool is_inert (void) const { return ref_count.get_unsafe () == HB_REFERENCE_COUNT_INERT_VALUE; }

  inline bool is_valid (void) const { return ref_count.get_unsafe () > 0; }

};

/* user_data */

#define HB_USER_DATA_ARRAY_INIT {HB_MUTEX_INIT, HB_LOCKABLE_SET_INIT}

struct hb_user_data_array_t

{

  struct hb_user_data_item_t {

    hb_user_data_key_t *key;

    void *data;

    hb_destroy_func_t destroy;

    inline bool operator == (hb_user_data_key_t *other_key) const { return key == other_key; }

    inline bool operator == (hb_user_data_item_t &other) const { return key == other.key; }

    void finish (void) { if (destroy) destroy (data); }

  };

  hb_mutex_t lock;

  hb_lockable_set_t<hb_user_data_item_t, hb_mutex_t> items;

  inline void init (void) { lock.init (); items.init (); }

  HB_INTERNAL bool set (hb_user_data_key_t *key,

			void *              data,

			hb_destroy_func_t   destroy,

			hb_bool_t           replace);

  HB_INTERNAL void *get (hb_user_data_key_t *key);

  inline void finish (void) { items.finish (lock); lock.finish (); }

};

/* object_header */

struct hb_object_header_t

{

  hb_reference_count_t ref_count;

  hb_user_data_array_t user_data;

#define HB_OBJECT_HEADER_STATIC {HB_REFERENCE_COUNT_INIT, HB_USER_DATA_ARRAY_INIT}

  private:

  ASSERT_POD ();

};

/* object */

template <typename Type>

static inline void hb_object_trace (const Type *obj, const char *function)

{

  DEBUG_MSG (OBJECT, (void *) obj,

	     "%s refcount=%d",

	     function,

	     obj ? obj->header.ref_count.get_unsafe () : 0);

}

template <typename Type>

static inline Type *hb_object_create (void)

{

  Type *obj = (Type *) calloc (1, sizeof (Type));

  if (unlikely (!obj))

    return obj;

  hb_object_init (obj);

  hb_object_trace (obj, HB_FUNC);

  return obj;

}

template <typename Type>

static inline void hb_object_init (Type *obj)

{

  obj->header.ref_count.init (1);

  obj->header.user_data.init ();

}

template <typename Type>

static inline bool hb_object_is_inert (const Type *obj)

{

  return unlikely (obj->header.ref_count.is_inert ());

}

template <typename Type>

static inline bool hb_object_is_valid (const Type *obj)

{

  return likely (obj->header.ref_count.is_valid ());

}

template <typename Type>

static inline Type *hb_object_reference (Type *obj)

{

  hb_object_trace (obj, HB_FUNC);

  if (unlikely (!obj || hb_object_is_inert (obj)))

    return obj;

  assert (hb_object_is_valid (obj));

  obj->header.ref_count.inc ();

  return obj;

}

template <typename Type>

static inline bool hb_object_destroy (Type *obj)

{

  hb_object_trace (obj, HB_FUNC);

  if (unlikely (!obj || hb_object_is_inert (obj)))

    return false;

  assert (hb_object_is_valid (obj));

  if (obj->header.ref_count.dec () != 1)

    return false;

  obj->header.ref_count.finish (); /* Do this before user_data */

  obj->header.user_data.finish ();

  return true;

}

template <typename Type>

static inline bool hb_object_set_user_data (Type               *obj,

					    hb_user_data_key_t *key,

					    void *              data,

					    hb_destroy_func_t   destroy,

					    hb_bool_t           replace)

{

  if (unlikely (!obj || hb_object_is_inert (obj)))

    return false;

  assert (hb_object_is_valid (obj));

  return obj->header.user_data.set (key, data, destroy, replace);

}

template <typename Type>

static inline void *hb_object_get_user_data (Type               *obj,

					     hb_user_data_key_t *key)

{

  if (unlikely (!obj || hb_object_is_inert (obj)))

    return NULL;

  assert (hb_object_is_valid (obj));

  return obj->header.user_data.get (key);

}

#endif /* HB_OBJECT_PRIVATE_HH */