完成Maat_hierarchy规则加载重构的代码编写，未编译。

src/entry/Maat_garbage_collection.cpp

@@ -0,0 +1,73 @@
+#include <sys/queue.h>
+
+struct Maat_garbage_bag
+{
+	time_t create_time;
+	int timeout;
+	int ok_times;
+	void *garbage;
+	void (* garbage_free)(void *garbage);
+	TAILQ_ENTRY(Maat_garbage_bag) entries;
+};
+TAILQ_HEAD(Maat_garbage_bag, Maat_garbage_q);
+
+struct Maat_garbage_bin
+{
+	Maat_garbage_q garbage_q;
+	size_t bag_cnt;
+	int timeout_seconds;
+};
+struct Maat_garbage_bin* Maat_garbage_bin_new(int default_timeout)
+{
+	struct Maat_garbage_bin* bin=ALLOC(struct Maat_garbage_bin, 1);
+	TAILQ_INIT(bin->garbage_q);
+	bin->timeout_seconds=default_timeout;
+	return bin;
+}
+void Maat_garbage_bin_free(struct Maat_garbage_bin* bin)
+{
+	struct Maat_garbage_bag* p=NULL;
+	while (p=TAILQ_FIRST(&bin->garbage_q))
+	{
+		p->garbage_free(p->garbage);
+		TAILQ_REMOVE(&bin->garbage_q, p, entries);
+		free(p);
+	}
+
+	free(bin);
+	return;
+}
+void Maat_garbage_bag(struct Maat_garbage_bin* bin, void* garbage, void (* func)(void *))
+{
+	struct Maat_garbage_bag* bag=ALLOC(	struct Maat_garbage_bag, 1);
+	bag->create_time=time(NULL);
+	bag->timeout=bin->timeout_seconds;
+	bag->garbage=garbage;
+	bag->garbage_free=func;
+	TAILQ_INSERT_TAIL(&bin->garbage_q, bag, entries);
+	bin->bag_cnt++;
+}
+void Maat_garbage_collect(struct Maat_garbage_bin* bin)
+{
+	struct Maat_garbage_bag* p=NULL, *tmp=NULL;
+	int n_clollected=0, n_bag=0;
+	time_t now=time(NULL);
+
+	for(p=TAILQ_FIRST(&bin->garbage_q); p!=NULL; p=tmp)
+	{
+		tmp=TAILQ_NEXT(p, entries);
+		if(now-p->create_time>p->timeout)
+		{
+			p->garbage_free(p->garbage);
+			TAILQ_REMOVE(&bin->garbage_q, p, entries);
+			free(p);
+			n_clollected++;
+		}
+		n_bag++;
+	}
+
+	assert(bin->bag_cnt==n_bag);
+	bin->bag_cnt-=n_clollected;
+	return;
+}
+