ZK Watcher触发条件全测试

ZOOAPI int zoo_acreate(zhandle_t *zh, const char *path, const char *value, 
        int valuelen, const struct ACL_vector *acl, int flags,
        string_completion_t completion, const void *data);

ZOOAPI int zoo_adelete(zhandle_t *zh, const char *path, int version, 
        void_completion_t completion, const void *data);
ZOOAPI int zoo_aset(zhandle_t *zh, const char *path, const char *buffer, int buflen, 
        int version, stat_completion_t completion, const void *data);

// \brief checks the existence of a node in zookeeper.
ZOOAPI int zoo_aexists(zhandle_t *zh, const char *path, int watch, 
        stat_completion_t completion, const void *data);
ZOOAPI int zoo_awexists(zhandle_t *zh, const char *path, 
        watcher_fn watcher, void* watcherCtx, 
        stat_completion_t completion, const void *data);
 
// \brief gets the data associated with a node.
ZOOAPI int zoo_aget(zhandle_t *zh, const char *path, int watch, 
        data_completion_t completion, const void *data);
ZOOAPI int zoo_awget(zhandle_t *zh, const char *path, 
        watcher_fn watcher, void* watcherCtx, 
        data_completion_t completion, const void *data);
 
// \brief lists the children of a node.
ZOOAPI int zoo_aget_children(zhandle_t *zh, const char *path, int watch, 
        strings_completion_t completion, const void *data);
ZOOAPI int zoo_awget_children(zhandle_t *zh, const char *path,
        watcher_fn watcher, void* watcherCtx, 
        strings_completion_t completion, const void *data);

/**
 * \brief signature of a watch function.
 * 
 * There are two ways to receive watch notifications: legacy and watcher object.
 * <p>
 * The legacy style, an application wishing to receive events from ZooKeeper must 
 * first implement a function with this signature and pass a pointer to the function 
 * to \ref zookeeper_init. Next, the application sets a watch by calling one of 
 * the getter API that accept the watch integer flag (for example, \ref zoo_aexists, 
 * \ref zoo_get, etc).
 * <p>
 * The watcher object style uses an instance of a "watcher object" which in 
 * the C world is represented by a pair: a pointer to a function implementing this
 * signature and a pointer to watcher context -- handback user-specific data. 
 * When a watch is triggered this function will be called along with 
 * the watcher context. An application wishing to use this style must use
 * the getter API functions with the "w" prefix in their names (for example, \ref
 * zoo_awexists, \ref zoo_wget, etc).
 * 
 * \param zh zookeeper handle
 * \param type event type. This is one of the *_EVENT constants. 
 * \param state connection state. The state value will be one of the *_STATE constants.
 * \param path znode path for which the watcher is triggered. NULL if the event 
 * type is ZOO_SESSION_EVENT
 * \param watcherCtx watcher context.
 */
typedef void (*watcher_fn)(zhandle_t *zh, int type, 
        int state, const char *path,void *watcherCtx);