o added filter type.

lib/dev-mgr/dev-cache.h

@@ -9,21 +9,51 @@
 #ifndef _LVM_DEV_CACHE_H
 #define _LVM_DEV_CACHE_H
 
+/*
+ * All devices in LVM will be represented by one of these.
+ * pointer comparisons are valid.
+ */
 struct device {
 	char *name;
 	dev_t dev;
 };
 
-int init_dev_cache();
+struct dev_filter {
-void exit_dev_cache();
+	int (*fn)(struct device *dev, struct dev_cache_filter *f);
+	void *private;
+};
+
+
+/*
+ * The global device cache.
+ */
+int dev_cache_init(void);
+void dev_cache_exit(void);
+
+int dev_cache_add_dir(const char *path);
+struct device *dev_cache_get(const char *name);
+void dev_cache_put(struct device *d);
+
+
+/*
+ * Object for iterating through the cache.
+ */
+struct dev_iter;
+struct dev_iter dev_iter_create(struct dev_filter *f);
+void dev_iter_destroy(struct dev_iter *iter);
+
+struct device *dev_cache_iter_get(struct dev_iter *iter);
+void dev_cache_iter_put(struct dev_iter *iter);
+
+/* returns 0 on eof */
+int dev_cache_next(struct dev_iter *iter);
 
-struct device *get_device(const char *name);
-void put_device(struct device *d);
 
 /*
  * All io should use these routines, rather than opening the devices
  * by hand.  You do not have to call an open routine.
  */
+uint64_t dev_get_size(struct device *dev); /* in 512 byte sectors */
 ssize_t dev_read(struct device *dev, size_t offset, size_t len, void *buffer);
 ssize_t dev_write(struct device *dev, size_t offset, size_t len, void *buffer);