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/*
* 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_HH
#define HB_OBJECT_HH
#include "hb.hh"
#include "hb-atomic.hh"
#include "hb-mutex.hh"
#include "hb-vector.hh"
/*
* Lockable set
*/
template <typename item_t, typename lock_t>
struct hb_lockable_set_t
{
hb_vector_t<item_t> items;
void init () { items.init (); }
template <typename T>
item_t *replace_or_insert (T v, lock_t &l, bool replace)
{
l.lock ();
item_t *item = items.lsearch (v);
if (item) {
if (replace) {
item_t old = *item;
*item = v;
l.unlock ();
old.fini ();
}
else {
item = nullptr;
l.unlock ();
}
} else {
item = items.push (v);
l.unlock ();
}
return items.in_error () ? nullptr : item;
}
template <typename T>
void remove (T v, lock_t &l)
{
l.lock ();
item_t *item = items.lsearch (v);
if (item)
{
item_t old = *item;
*item = std::move (items.tail ());
items.pop ();
l.unlock ();
old.fini ();
} else {
l.unlock ();
}
}
template <typename T>
bool find (T v, item_t *i, lock_t &l)
{
l.lock ();
item_t *item = items.lsearch (v);
if (item)
*i = *item;
l.unlock ();
return !!item;
}
template <typename T>
item_t *find_or_insert (T v, lock_t &l)
{
l.lock ();
item_t *item = items.find (v);
if (!item) {
item = items.push (v);
}
l.unlock ();
return item;
}
void fini (lock_t &l)
{
if (!items.length)
{
/* No need to lock. */
items.fini ();
return;
}
l.lock ();
while (items.length)
{
item_t old = items.tail ();
items.pop ();
l.unlock ();
old.fini ();
l.lock ();
}
items.fini ();
l.unlock ();
}
};
/*
* Reference-count.
*/
struct hb_reference_count_t
{
mutable hb_atomic_int_t ref_count;
void init (int v = 1) { ref_count = v; }
int get_relaxed () const { return ref_count; }
int inc () const { return ref_count.inc (); }
int dec () const { return ref_count.dec (); }
void fini () { ref_count = -0x0000DEAD; }
bool is_inert () const { return !ref_count; }
bool is_valid () const { return ref_count > 0; }
};
/* user_data */
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;
bool operator == (const hb_user_data_key_t *other_key) const { return key == other_key; }
bool operator == (const hb_user_data_item_t &other) const { return key == other.key; }
void fini () { if (destroy) destroy (data); }
};
hb_mutex_t lock;
hb_lockable_set_t<hb_user_data_item_t, hb_mutex_t> items;
void init () { lock.init (); items.init (); }
void fini () { items.fini (lock); lock.fini (); }
bool set (hb_user_data_key_t *key,
void * data,
hb_destroy_func_t destroy,
hb_bool_t replace)
{
if (!key)
return false;
if (replace) {
if (!data && !destroy) {
items.remove (key, lock);
return true;
}
}
hb_user_data_item_t item = {key, data, destroy};
bool ret = !!items.replace_or_insert (item, lock, (bool) replace);
return ret;
}
void *get (hb_user_data_key_t *key)
{
hb_user_data_item_t item = {nullptr, nullptr, nullptr};
return items.find (key, &item, lock) ? item.data : nullptr;
}
};
/*
* Object header
*/
struct hb_object_header_t
{
hb_reference_count_t ref_count;
mutable hb_atomic_int_t writable = 0;
hb_atomic_ptr_t<hb_user_data_array_t> user_data;
bool is_inert () const { return !ref_count.get_relaxed (); }
};
#define HB_OBJECT_HEADER_STATIC {}
/*
* 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_relaxed () : 0);
}
template <typename Type, typename ...Ts>
static inline Type *hb_object_create (Ts... ds)
{
Type *obj = (Type *) hb_calloc (1, sizeof (Type));
if (unlikely (!obj))
return obj;
new (obj) Type (std::forward<Ts> (ds)...);
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 ();
obj->header.writable = true;
obj->header.user_data.init ();
}
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 bool hb_object_is_immutable (const Type *obj)
{
return !obj->header.writable;
}
template <typename Type>
static inline void hb_object_make_immutable (const Type *obj)
{
obj->header.writable = false;
}
template <typename Type>
static inline Type *hb_object_reference (Type *obj)
{
hb_object_trace (obj, HB_FUNC);
if (unlikely (!obj || obj->header.is_inert ()))
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 || obj->header.is_inert ()))
return false;
assert (hb_object_is_valid (obj));
if (obj->header.ref_count.dec () != 1)
return false;
hb_object_fini (obj);
if (!std::is_trivially_destructible<Type>::value)
obj->~Type ();
return true;
}
template <typename Type>
static inline void hb_object_fini (Type *obj)
{
obj->header.ref_count.fini (); /* Do this before user_data */
hb_user_data_array_t *user_data = obj->header.user_data.get_acquire ();
if (user_data)
{
user_data->fini ();
hb_free (user_data);
obj->header.user_data.set_relaxed (nullptr);
}
}
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 || obj->header.is_inert ()))
return false;
assert (hb_object_is_valid (obj));
retry:
hb_user_data_array_t *user_data = obj->header.user_data.get_acquire ();
if (unlikely (!user_data))
{
user_data = (hb_user_data_array_t *) hb_calloc (1, sizeof (hb_user_data_array_t));
if (unlikely (!user_data))
return false;
user_data->init ();
if (unlikely (!obj->header.user_data.cmpexch (nullptr, user_data)))
{
user_data->fini ();
hb_free (user_data);
goto retry;
}
}
return 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 || obj->header.is_inert ()))
return nullptr;
assert (hb_object_is_valid (obj));
hb_user_data_array_t *user_data = obj->header.user_data.get_acquire ();
if (!user_data)
return nullptr;
return user_data->get (key);
}
#endif /* HB_OBJECT_HH */