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Diffstat (limited to 'source/blender/blenkernel/intern/anonymous_attribute.cc')
-rw-r--r-- | source/blender/blenkernel/intern/anonymous_attribute.cc | 118 |
1 files changed, 118 insertions, 0 deletions
diff --git a/source/blender/blenkernel/intern/anonymous_attribute.cc b/source/blender/blenkernel/intern/anonymous_attribute.cc new file mode 100644 index 00000000000..67611053d83 --- /dev/null +++ b/source/blender/blenkernel/intern/anonymous_attribute.cc @@ -0,0 +1,118 @@ +/* + * 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) { + 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(); +} |