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/*
* This program 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 2
* of the License, or (at your option) any later version.
*
* This program 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 this program; if not, write to the Free Software Foundation,
* Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
#include "BKE_anonymous_attribute.hh"
using namespace blender::bke;
/**
* A struct that identifies an attribute. It's lifetime is managed by an atomic reference count.
*
* Additionally, this struct can be strongly or weakly owned. The difference is that strong
* ownership means that attributes with this id will be kept around. Weak ownership just makes sure
* that the struct itself stays alive, but corresponding attributes might still be removed
* automatically.
*/
struct AnonymousAttributeID {
/**
* Total number of references to this attribute id. Once this reaches zero, the struct can be
* freed. This includes strong and weak references.
*/
mutable std::atomic<int> refcount_tot = 0;
/**
* Number of strong references to this attribute id. When this is zero, the corresponding
* attributes can be removed from geometries automatically.
*/
mutable std::atomic<int> refcount_strong = 0;
/**
* Only used to identify this struct in a debugging session.
*/
std::string debug_name;
/**
* Unique name of the this attribute id during the current session.
*/
std::string internal_name;
};
/** Every time this function is called, it outputs a different name. */
static std::string get_new_internal_name()
{
static std::atomic<int> index = 0;
const int next_index = index.fetch_add(1);
return "anonymous_attribute_" + std::to_string(next_index);
}
AnonymousAttributeID *BKE_anonymous_attribute_id_new_weak(const char *debug_name)
{
AnonymousAttributeID *anonymous_id = new AnonymousAttributeID();
anonymous_id->debug_name = debug_name;
anonymous_id->internal_name = get_new_internal_name();
anonymous_id->refcount_tot.store(1);
return anonymous_id;
}
AnonymousAttributeID *BKE_anonymous_attribute_id_new_strong(const char *debug_name)
{
AnonymousAttributeID *anonymous_id = new AnonymousAttributeID();
anonymous_id->debug_name = debug_name;
anonymous_id->internal_name = get_new_internal_name();
anonymous_id->refcount_tot.store(1);
anonymous_id->refcount_strong.store(1);
return anonymous_id;
}
bool BKE_anonymous_attribute_id_has_strong_references(const AnonymousAttributeID *anonymous_id)
{
return anonymous_id->refcount_strong.load() >= 1;
}
void BKE_anonymous_attribute_id_increment_weak(const AnonymousAttributeID *anonymous_id)
{
anonymous_id->refcount_tot.fetch_add(1);
}
void BKE_anonymous_attribute_id_increment_strong(const AnonymousAttributeID *anonymous_id)
{
anonymous_id->refcount_tot.fetch_add(1);
anonymous_id->refcount_strong.fetch_add(1);
}
void BKE_anonymous_attribute_id_decrement_weak(const AnonymousAttributeID *anonymous_id)
{
const int new_refcount = anonymous_id->refcount_tot.fetch_sub(1) - 1;
if (new_refcount == 0) {
BLI_assert(anonymous_id->refcount_strong == 0);
delete anonymous_id;
}
}
void BKE_anonymous_attribute_id_decrement_strong(const AnonymousAttributeID *anonymous_id)
{
anonymous_id->refcount_strong.fetch_sub(1);
BKE_anonymous_attribute_id_decrement_weak(anonymous_id);
}
const char *BKE_anonymous_attribute_id_debug_name(const AnonymousAttributeID *anonymous_id)
{
return anonymous_id->debug_name.c_str();
}
const char *BKE_anonymous_attribute_id_internal_name(const AnonymousAttributeID *anonymous_id)
{
return anonymous_id->internal_name.c_str();
}
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