Consolidate reference counting code.

10 files changed, 124 insertions, 27 deletions

diff --git a/libdimension/Makefile.am b/libdimension/Makefile.am
index 3dbbbb3..e824308 100644
--- a/libdimension/Makefile.am
+++ b/libdimension/Makefile.am
@@ -53,6 +53,7 @@ nobase_include_HEADERS = dimension.h                                           \
                          dimension/polynomial.h                                \
                          dimension/progress.h                                  \
                          dimension/raytrace.h                                  \
+                         dimension/refcount.h                                  \
                          dimension/scene.h                                     \
                          dimension/sky_sphere.h                                \
                          dimension/texture.h                                   \
@@ -102,6 +103,7 @@ libdimension_la_SOURCES = $(nobase_include_HEADERS)                            \
                           prtree.c                                             \
                           prtree.h                                             \
                           raytrace.c                                           \
+                          refcount.c                                           \
                           reflective.c                                         \
                           scene.c                                              \
                           sky_sphere.c                                         \
diff --git a/libdimension/csg.c b/libdimension/csg.c
index 05f0b60..caecee0 100644
--- a/libdimension/csg.c
+++ b/libdimension/csg.c
@@ -32,12 +32,10 @@ dmnsn_csg_cascade(const dmnsn_object *csg, dmnsn_object *object)
 {
   if (!object->texture && csg->texture) {
     object->texture = csg->texture;
-    ++*object->texture->refcount;
   }
 
   if (!object->interior && csg->interior) {
     object->interior = csg->interior;
-    ++*object->interior->refcount;
   }
 
   object->trans = dmnsn_matrix_mul(csg->trans, object->trans);
diff --git a/libdimension/dimension.h b/libdimension/dimension.h
index 3f0ea57..33b8378 100644
--- a/libdimension/dimension.h
+++ b/libdimension/dimension.h
@@ -77,6 +77,7 @@ typedef void dmnsn_free_fn(void *ptr);
 #include <dimension/inline.h>
 #include <dimension/error.h>
 #include <dimension/malloc.h>
+#include <dimension/refcount.h>
 #include <dimension/array.h>
 #include <dimension/dictionary.h>
 #include <dimension/progress.h>
diff --git a/libdimension/dimension/interior.h b/libdimension/dimension/interior.h
index 88af0b9..76f0a32 100644
--- a/libdimension/dimension/interior.h
+++ b/libdimension/dimension/interior.h
@@ -33,7 +33,7 @@ typedef struct dmnsn_interior {
   void *ptr;
 
   /** @internal Reference count. */
-  unsigned int *refcount;
+  dmnsn_refcount *refcount;
 } dmnsn_interior;
 
 /**
diff --git a/libdimension/dimension/refcount.h b/libdimension/dimension/refcount.h
new file mode 100644
index 0000000..14f31ab
--- /dev/null
+++ b/libdimension/dimension/refcount.h
@@ -0,0 +1,55 @@
+/*************************************************************************
+ * Copyright (C) 2011 Tavian Barnes <tavianator@tavianator.com>          *
+ *                                                                       *
+ * This file is part of The Dimension Library.                           *
+ *                                                                       *
+ * The Dimension Library is free software; you can redistribute it and/  *
+ * or modify it under the terms of the GNU Lesser General Public License *
+ * as published by the Free Software Foundation; either version 3 of the *
+ * License, or (at your option) any later version.                       *
+ *                                                                       *
+ * The Dimension Library 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  *
+ * Lesser General Public License for more details.                       *
+ *                                                                       *
+ * You should have received a copy of the GNU Lesser General Public      *
+ * License along with this program.  If not, see                         *
+ * <http://www.gnu.org/licenses/>.                                       *
+ *************************************************************************/
+
+/**
+ * @file
+ * Generic reference count implementation.
+ */
+
+/**
+ * Increment a reference count.
+ * @param[in,out] object  The reference-counted object to acquire.
+ */
+#define DMNSN_INCREF(obj) ((void)++(*(obj)->refcount))
+
+/**
+ * Decrement a reference count.
+ * @param[in,out] object  The reference-counted object to release.
+ * @return Whether the object is now garbage.
+ */
+#define DMNSN_DECREF(obj) (*(obj)->refcount == 0 || --(*(obj)->refcount) == 0)
+
+/**
+ * Reference counter.
+ */
+typedef unsigned int dmnsn_refcount;
+
+/**
+ * Create a reference count.
+ * @return A new reference counter, initialized to zero (a "borrowed" reference,
+ *         which will be garbage-collected the first time it is deleted).
+ */
+dmnsn_refcount *dmnsn_new_refcount(void);
+
+/**
+ * Delete a reference count.  Raises an error if the reference count wasn't
+ * zero.
+ */
+void dmnsn_delete_refcount(dmnsn_refcount *refcount);
diff --git a/libdimension/dimension/texture.h b/libdimension/dimension/texture.h
index 31ab86b..8051c02 100644
--- a/libdimension/dimension/texture.h
+++ b/libdimension/dimension/texture.h
@@ -31,8 +31,8 @@ typedef struct {
   dmnsn_matrix trans;     /**< Transformation matrix. */
   dmnsn_matrix trans_inv; /**< The inverse of the transformation matrix. */
 
-  unsigned int *refcount; /**< @internal Reference count. */
-  bool should_init;       /**< @internal Whether to initialize the texture. */
+  dmnsn_refcount *refcount; /**< @internal Reference count. */
+  bool should_init;         /**< @internal Whether to initialize the texture. */
 } dmnsn_texture;
 
 /**
diff --git a/libdimension/interior.c b/libdimension/interior.c
index 939bd4f..0eec274 100644
--- a/libdimension/interior.c
+++ b/libdimension/interior.c
@@ -33,8 +33,7 @@ dmnsn_new_interior(void)
   dmnsn_interior *interior = dmnsn_malloc(sizeof(dmnsn_interior));
   interior->ior       = 1.0;
   interior->free_fn   = NULL;
-  interior->refcount  = dmnsn_malloc(sizeof(unsigned int));
-  *interior->refcount = 1;
+  interior->refcount  = dmnsn_new_refcount();
   return interior;
 }
 
@@ -42,15 +41,11 @@ dmnsn_new_interior(void)
 void
 dmnsn_delete_interior(dmnsn_interior *interior)
 {
-  if (interior) {
-    if (*interior->refcount <= 1) {
-      if (interior->free_fn) {
-        interior->free_fn(interior->ptr);
-      }
-      dmnsn_free(interior->refcount);
-      dmnsn_free(interior);
-    } else {
-      --*interior->refcount;
+  if (interior && DMNSN_DECREF(interior)) {
+    if (interior->free_fn) {
+      interior->free_fn(interior->ptr);
     }
+    dmnsn_delete_refcount(interior->refcount);
+    dmnsn_free(interior);
   }
 }
diff --git a/libdimension/object.c b/libdimension/object.c
index dda80f0..7c4a714 100644
--- a/libdimension/object.c
+++ b/libdimension/object.c
@@ -68,10 +68,15 @@ dmnsn_initialize_object(dmnsn_object *object)
   bool should_init = false;
   dmnsn_matrix old_trans = object->trans;
   if (object->texture) {
+    DMNSN_INCREF(object->texture);
     should_init = object->texture->should_init;
     object->texture->should_init = false;
   }
 
+  if (object->interior) {
+    DMNSN_INCREF(object->interior);
+  }
+
   if (object->initialize_fn) {
     object->initialize_fn(object);
   }
diff --git a/libdimension/refcount.c b/libdimension/refcount.c
new file mode 100644
index 0000000..66bc010
--- /dev/null
+++ b/libdimension/refcount.c
@@ -0,0 +1,46 @@
+/*************************************************************************
+ * Copyright (C) 2011 Tavian Barnes <tavianator@tavianator.com>          *
+ *                                                                       *
+ * This file is part of The Dimension Library.                           *
+ *                                                                       *
+ * The Dimension Library is free software; you can redistribute it and/  *
+ * or modify it under the terms of the GNU Lesser General Public License *
+ * as published by the Free Software Foundation; either version 3 of the *
+ * License, or (at your option) any later version.                       *
+ *                                                                       *
+ * The Dimension Library 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  *
+ * Lesser General Public License for more details.                       *
+ *                                                                       *
+ * You should have received a copy of the GNU Lesser General Public      *
+ * License along with this program.  If not, see                         *
+ * <http://www.gnu.org/licenses/>.                                       *
+ *************************************************************************/
+
+/**
+ * @file
+ * Reference counts.
+ */
+
+#include "dimension.h"
+
+dmnsn_refcount *
+dmnsn_new_refcount(void)
+{
+  dmnsn_refcount *refcount = dmnsn_malloc(sizeof(dmnsn_refcount));
+  *refcount = 0;
+  return refcount;
+}
+
+void
+dmnsn_delete_refcount(dmnsn_refcount *refcount)
+{
+  if (refcount) {
+    if (*refcount != 0) {
+      dmnsn_error("Attempt to delete non-zero reference count.");
+    }
+
+    dmnsn_free(refcount);
+  }
+}
diff --git a/libdimension/texture.c b/libdimension/texture.c
index d0c1944..5f3b98d 100644
--- a/libdimension/texture.c
+++ b/libdimension/texture.c
@@ -33,8 +33,7 @@ dmnsn_new_texture(void)
   texture->pigment     = NULL;
   texture->finish      = NULL;
   texture->trans       = dmnsn_identity_matrix();
-  texture->refcount    = dmnsn_malloc(sizeof(unsigned int));
-  *texture->refcount   = 1;
+  texture->refcount    = dmnsn_new_refcount();
   texture->should_init = true;
   return texture;
 }
@@ -43,15 +42,11 @@ dmnsn_new_texture(void)
 void
 dmnsn_delete_texture(dmnsn_texture *texture)
 {
-  if (texture) {
-    if (*texture->refcount <= 1) {
-      dmnsn_delete_finish(texture->finish);
-      dmnsn_delete_pigment(texture->pigment);
-      dmnsn_free(texture->refcount);
-      dmnsn_free(texture);
-    } else {
-      --*texture->refcount;
-    }
+  if (texture && DMNSN_DECREF(texture)) {
+    dmnsn_delete_finish(texture->finish);
+    dmnsn_delete_pigment(texture->pigment);
+    dmnsn_delete_refcount(texture->refcount);
+    dmnsn_free(texture);
   }
 }