pkg: implement refcounting and a deeper cache

cache.c

@@ -32,7 +32,7 @@ pkg_cache_lookup(const char *id)
 	PKG_FOREACH_LIST_ENTRY(pkg_cache, pkg)
 	{
 		if (!strcmp(pkg->id, id))
-			return pkg;
+			return pkg_ref(pkg);
 	}
 
 	return NULL;
@@ -47,6 +47,8 @@ pkg_cache_lookup(const char *id)
 void
 pkg_cache_add(pkg_t *pkg)
 {
+	pkg_ref(pkg);
+
 	pkg->next = pkg_cache;
 	pkg_cache = pkg;
 
@@ -76,3 +78,14 @@ pkg_cache_remove(pkg_t *pkg)
 			pkg_cache = pkg->next;
 	}
 }
+
+void
+pkg_cache_free(void)
+{
+	pkg_t *iter, *iter2;
+
+	PKG_FOREACH_LIST_ENTRY_SAFE(pkg_cache, iter2, iter)
+	{
+		pkg_free(iter);
+	}
+}

main.c

@@ -899,5 +899,7 @@ out_println:
 
 out:
 	pkg_tuple_free_global();
+	pkg_cache_free();
+
 	return ret;
 }

pkg.c

@@ -238,7 +238,7 @@ pkg_new_from_file(const char *filename, FILE *f, unsigned int flags)
 	}
 
 	fclose(f);
-	return pkg;
+	return pkg_ref(pkg);
 }
 
 void
@@ -283,6 +283,21 @@ pkg_free(pkg_t *pkg)
 	free(pkg);
 }
 
+pkg_t *
+pkg_ref(pkg_t *pkg)
+{
+	pkg->refcount++;
+	return pkg;
+}
+
+void
+pkg_unref(pkg_t *pkg)
+{
+	pkg->refcount--;
+	if (pkg->refcount <= 0)
+		pkg_free(pkg);
+}
+
 static inline pkg_t *
 pkg_try_specific_path(const char *path, const char *name, unsigned int flags)
 {
@@ -338,7 +353,7 @@ pkg_scan_dir(const char *path, pkg_iteration_func_t func)
 		if (pkg != NULL)
 		{
 			func(pkg);
-			pkg_free(pkg);
+			pkg_unref(pkg);
 		}
 	}
 
@@ -809,7 +824,7 @@ pkg_report_graph_error(pkg_t *pkg, pkg_dependency_t *node, unsigned int eflags)
 	}
 
 	if (pkg != NULL)
-		pkg_free(pkg);
+		pkg_unref(pkg);
 
 	return eflags;
 }
@@ -834,11 +849,16 @@ pkg_walk_list(pkg_dependency_t *deplist,
 		pkgdep = pkg_verify_dependency(node, flags, &eflags);
 		if (eflags != PKG_ERRF_OK)
 			return pkg_report_graph_error(pkgdep, node, eflags);
-		if (pkgdep->flags & PKG_PROPF_CACHED)
+		if (pkgdep->flags & PKG_PROPF_SEEN)
+		{
+			pkg_unref(pkgdep);
 			continue;
+		}
 
+		pkgdep->flags |= PKG_PROPF_SEEN;
 		eflags = pkg_traverse(pkgdep, func, data, depth - 1, flags);
-		pkg_free(pkgdep);
+		pkgdep->flags &= ~PKG_PROPF_SEEN;
+		pkg_unref(pkgdep);
 
 		/* optimization: if a break has been found in the depgraph, quit walking it */
 		if (eflags != PKG_ERRF_OK)
@@ -875,12 +895,12 @@ pkg_walk_conflicts_list(pkg_t *root, pkg_dependency_t *deplist, unsigned int fla
 				fprintf(error_msgout, "It may be possible to ignore this conflict and continue, try the\n");
 				fprintf(error_msgout, "PKG_CONFIG_IGNORE_CONFLICTS environment variable.\n");
 
-				pkg_free(pkgdep);
+				pkg_unref(pkgdep);
 
 				return PKG_ERRF_PACKAGE_CONFLICT;
 			}
 
-			pkg_free(pkgdep);
+			pkg_unref(pkgdep);
 		}
 	}
 
@@ -949,7 +969,6 @@ pkg_cflags(pkg_t *root, pkg_fragment_t **list, int maxdepth, unsigned int flags)
 	int eflag;
 
 	eflag = pkg_traverse(root, pkg_cflags_collect, list, maxdepth, flags);
-
 	if (eflag != PKG_ERRF_OK)
 	{
 		pkg_fragment_free(*list);

pkg.h

@@ -81,10 +81,12 @@ typedef struct pkg_queue_ {
 #define PKG_PROPF_NONE			0x0
 #define PKG_PROPF_VIRTUAL		0x1
 #define PKG_PROPF_CACHED		0x2
+#define PKG_PROPF_SEEN			0x4
 
 struct pkg_ {
 	pkg_t *prev, *next;				/* for pkg_cache */
 
+	int refcount;
 	char *id;
 	char *filename;
 	char *realname;
@@ -131,6 +133,8 @@ typedef void (*pkg_traverse_func_t)(pkg_t *pkg, void *data, unsigned int flags);
 typedef bool (*pkg_queue_apply_func_t)(pkg_t *world, void *data, int maxdepth, unsigned int flags);
 
 /* pkg.c */
+pkg_t *pkg_ref(pkg_t *pkg);
+void pkg_unref(pkg_t *pkg);
 void pkg_free(pkg_t *pkg);
 pkg_t *pkg_find(const char *name, unsigned int flags);
 void pkg_scan(const char *search_path, pkg_iteration_func_t func);
@@ -191,5 +195,6 @@ bool pkg_queue_validate(pkg_queue_t *head, int maxdepth, unsigned int flags);
 pkg_t *pkg_cache_lookup(const char *id);
 void pkg_cache_add(pkg_t *pkg);
 void pkg_cache_remove(pkg_t *pkg);
+void pkg_cache_free(void);
 
 #endif