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 Sourcecode: zookeeper version 3.2.2+dfsg33.2.2+dfsg3-23.2.2+dfsg3-33.3.0+dfsg1-13.3.1+dfsg1-23.3.1+dfsg1-2build13.3.3+dfsg1-13.3.3+dfsg2-13.3.3+dfsg2-1ubuntu13.3.3+dfsg2-2

# zookeeper.h

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/**
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements.  See the NOTICE file
* distributed with this work for additional information
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License.  You may obtain a copy of the License at
*
*
* Unless required by applicable law or agreed to in writing, software
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
*/

#ifndef ZOOKEEPER_H_
#define ZOOKEEPER_H_

#include <sys/time.h>
#include <stdio.h>

#include "zookeeper_version.h"
#include "recordio.h"
#include "zookeeper.jute.h"

/**
* \file zookeeper.h
* \brief ZooKeeper functions and definitions.
*
* ZooKeeper is a network service that may be backed by a cluster of
* synchronized servers. The data in the service is represented as a tree
* of data nodes. Each node has data, children, an ACL, and status information.
* The data for a node is read and write in its entirety.
*
* ZooKeeper clients can leave watches when they queries the data or children
* of a node. If a watch is left, that client will be notified of the change.
* The notification is a one time trigger. Subsequent chances to the node will
* not trigger a notification unless the client issues a querity with the watch
* flag set. If the client is ever disconnected from the service, even if the
* disconnection is temporary, the watches of the client will be removed from
* the service, so a client must treat a disconnect notification as an implicit
* trigger of all outstanding watches.
*
* When a node is created, it may be flagged as an ephemeral node. Ephemeral
* nodes are automatically removed when a client session is closed or when
* a session times out due to inactivity (the ZooKeeper runtime fills in
* periods of inactivity with pings). Ephemeral nodes cannot have children.
*
* ZooKeeper clients are identified by a server assigned session id. For
* security reasons The server
* also generates a corresponding password for a session. A client may save its
* id and corresponding password to persistent storage in order to use the
* session across program invocation boundaries.
*/

/* Support for building on various platforms */

// on cygwin we should take care of exporting/importing symbols properly
#ifdef DLL_EXPORT
#    define ZOOAPI __declspec(dllexport)
#else
#  if defined(__CYGWIN__) && !defined(USE_STATIC_LIB)
#    define ZOOAPI __declspec(dllimport)
#  else
#    define ZOOAPI
#  endif
#endif

/** zookeeper return constants **/

00074 enum ZOO_ERRORS {
00075   ZOK = 0, /*!< Everything is OK */

/** System and server-side errors.
* This is never thrown by the server, it shouldn't be used other than
* to indicate a range. Specifically error codes greater than this
* value, but lesser than {@link #ZAPIERROR}, are system errors. */
00081   ZSYSTEMERROR = -1,
00082   ZRUNTIMEINCONSISTENCY = -2, /*!< A runtime inconsistency was found */
00083   ZDATAINCONSISTENCY = -3, /*!< A data inconsistency was found */
00084   ZCONNECTIONLOSS = -4, /*!< Connection to the server has been lost */
00085   ZMARSHALLINGERROR = -5, /*!< Error while marshalling or unmarshalling data */
00086   ZUNIMPLEMENTED = -6, /*!< Operation is unimplemented */
00087   ZOPERATIONTIMEOUT = -7, /*!< Operation timeout */
00088   ZBADARGUMENTS = -8, /*!< Invalid arguments */
00089   ZINVALIDSTATE = -9, /*!< Invliad zhandle state */

/** API errors.
* This is never thrown by the server, it shouldn't be used other than
* to indicate a range. Specifically error codes greater than this
* value are API errors (while values less than this indicate a
*/
00097   ZAPIERROR = -100,
00098   ZNONODE = -101, /*!< Node does not exist */
00099   ZNOAUTH = -102, /*!< Not authenticated */
00100   ZBADVERSION = -103, /*!< Version conflict */
00101   ZNOCHILDRENFOREPHEMERALS = -108, /*!< Ephemeral nodes may not have children */
00102   ZNODEEXISTS = -110, /*!< The node already exists */
00103   ZNOTEMPTY = -111, /*!< The node has children */
00104   ZSESSIONEXPIRED = -112, /*!< The session has been expired by the server */
00105   ZINVALIDCALLBACK = -113, /*!< Invalid callback specified */
00106   ZINVALIDACL = -114, /*!< Invalid ACL specified */
00107   ZAUTHFAILED = -115, /*!< Client authentication failed */
00108   ZCLOSING = -116, /*!< ZooKeeper is closing */
00109   ZNOTHING = -117, /*!< (not error) no server responses to process */
00110   ZSESSIONMOVED = -118 /*!<session moved to another server, so operation is ignored */
};

#ifdef __cplusplus
extern "C" {
#endif

/**
*  @name Debug levels
*/
typedef enum {ZOO_LOG_LEVEL_ERROR=1,ZOO_LOG_LEVEL_WARN=2,ZOO_LOG_LEVEL_INFO=3,ZOO_LOG_LEVEL_DEBUG=4} ZooLogLevel;

/**
* @name ACL Consts
*/
extern ZOOAPI const int ZOO_PERM_WRITE;
extern ZOOAPI const int ZOO_PERM_CREATE;
extern ZOOAPI const int ZOO_PERM_DELETE;
extern ZOOAPI const int ZOO_PERM_ALL;

/** This Id represents anyone. */
extern ZOOAPI struct Id ZOO_ANYONE_ID_UNSAFE;
/** This Id is only usable to set ACLs. It will get substituted with the
* Id's the client authenticated with.
*/
extern ZOOAPI struct Id ZOO_AUTH_IDS;

/** This is a completely open ACL*/
extern ZOOAPI struct ACL_vector ZOO_OPEN_ACL_UNSAFE;
/** This ACL gives the world the ability to read. */
/** This ACL gives the creators authentication id's all permissions. */
extern ZOOAPI struct ACL_vector ZOO_CREATOR_ALL_ACL;

/**
* @name Interest Consts
* These constants are used to express interest in an event and to
* indicate to zookeeper which events have occurred. They can
* be ORed together to express multiple interests. These flags are
* used in the interest and event parameters of
* \ref zookeeper_interest and \ref zookeeper_process.
*/
// @{
extern ZOOAPI const int ZOOKEEPER_WRITE;
// @}

/**
* @name Create Flags
*
* These flags are used by zoo_create to affect node create. They may
* be ORed together to combine effects.
*/
// @{
extern ZOOAPI const int ZOO_EPHEMERAL;
extern ZOOAPI const int ZOO_SEQUENCE;
// @}

/**
* @name State Consts
* These constants represent the states of a zookeeper connection. They are
* possible parameters of the watcher callback.
*/
// @{
extern ZOOAPI const int ZOO_EXPIRED_SESSION_STATE;
extern ZOOAPI const int ZOO_AUTH_FAILED_STATE;
extern ZOOAPI const int ZOO_CONNECTING_STATE;
extern ZOOAPI const int ZOO_ASSOCIATING_STATE;
extern ZOOAPI const int ZOO_CONNECTED_STATE;
// @}

/**
* @name Watch Types
* These constants indicate the event that caused the watch event. They are
* possible values of the first parameter of the watcher callback.
*/
// @{
/**
* \brief a node has been created.
*
* This is only generated by watches on non-existent nodes. These watches
* are set using \ref zoo_exists.
*/
extern ZOOAPI const int ZOO_CREATED_EVENT;
/**
* \brief a node has been deleted.
*
* This is only generated by watches on nodes. These watches
* are set using \ref zoo_exists and \ref zoo_get.
*/
extern ZOOAPI const int ZOO_DELETED_EVENT;
/**
* \brief a node has changed.
*
* This is only generated by watches on nodes. These watches
* are set using \ref zoo_exists and \ref zoo_get.
*/
extern ZOOAPI const int ZOO_CHANGED_EVENT;
/**
* \brief a change as occurred in the list of children.
*
* This is only generated by watches on the child list of a node. These watches
* are set using \ref zoo_get_children.
*/
extern ZOOAPI const int ZOO_CHILD_EVENT;
/**
* \brief a session has been lost.
*
* This is generated when a client loses contact or reconnects with a server.
*/
extern ZOOAPI const int ZOO_SESSION_EVENT;

/**
* \brief a watch has been removed.
*
* This is generated when the server for some reason, probably a resource
* constraint, will no longer watch a node for a client.
*/
extern ZOOAPI const int ZOO_NOTWATCHING_EVENT;
// @}

/**
* \brief ZooKeeper handle.
*
* This is the handle that represents a connection to the ZooKeeper service.
* It is needed to invoke any ZooKeeper function. A handle is obtained using
* \ref zookeeper_init.
*/
00240 typedef struct _zhandle zhandle_t;

/**
* \brief client id structure.
*
* This structure holds the id and password for the session. This structure
* should be treated as opaque. It is received from the server when a session
* is established and needs to be sent back as-is when reconnecting a session.
*/
00249 typedef struct {
int64_t client_id;
char passwd[16];
} clientid_t;

/**
* \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.
*/
00280 typedef void (*watcher_fn)(zhandle_t *zh, int type,
int state, const char *path,void *watcherCtx);

/**
* \brief create a handle to used communicate with zookeeper.
*
* This method creates a new handle and a zookeeper session that corresponds
* to that handle. Session establishment is asynchronous, meaning that the
* session should not be considered established until (and unless) an
* event of state ZOO_CONNECTED_STATE is received.
* \param host comma separated host:port pairs, each corresponding to a zk
*   server. e.g. "127.0.0.1:3000,127.0.0.1:3001,127.0.0.1:3002"
* \param fn the global watcher callback function. When notifications are
*   triggered this function will be invoked.
* \param clientid the id of a previously established session that this
*   client will be reconnecting to. Pass 0 if not reconnecting to a previous
*   session. Clients can access the session id of an established, valid,
*   connection by calling \ref zoo_client_id. If the session corresponding to
*   the specified clientid has expired, or if the clientid is invalid for
*   any reason, the returned zhandle_t will be invalid -- the zhandle_t
*   state will indicate the reason for failure (typically
*   ZOO_EXPIRED_SESSION_STATE).
* \param context the handback object that will be associated with this instance
*   of zhandle_t. Application can access it (for example, in the watcher
*   callback) using \ref zoo_get_context. The object is not used by zookeeper
*   internally and can be null.
* \param flags reserved for future use. Should be set to zero.
* \return a pointer to the opaque zhandle structure. If it fails to create
* a new zhandle the function returns NULL and the errno variable
* indicates the reason.
*/
ZOOAPI zhandle_t *zookeeper_init(const char *host, watcher_fn fn,
int recv_timeout, const clientid_t *clientid, void *context, int flags);

/**
* \brief close the zookeeper handle and free up any resources.
*
* After this call, the client session will no longer be valid. The function
* will flush any outstanding send requests before return. As a result it may
* block.
*
* This method should only be called only once on a zookeeper handle. Calling
* twice will cause undefined (and probably undesirable behavior). Calling any other
* zookeeper method after calling close is undefined behaviour and should be avoided.
*
* \param zh the zookeeper handle obtained by a call to \ref zookeeper_init
* \return a result code. Regardless of the error code returned, the zhandle
* will be destroyed and all resources freed.
*
* ZOK - success
* ZBADARGUMENTS - invalid input parameters
* ZMARSHALLINGERROR - failed to marshall a request; possibly, out of memory
* ZOPERATIONTIMEOUT - failed to flush the buffers within the specified timeout.
* ZCONNECTIONLOSS - a network error occured while attempting to send request to server
* ZSYSTEMERROR -- a system (OS) error occured; it's worth checking errno to get details
*/
ZOOAPI int zookeeper_close(zhandle_t *zh);

/**
* \brief return the client session id, only valid if the connections
* is currently connected (ie. last watcher state is ZOO_CONNECTED_STATE)
*/
ZOOAPI const clientid_t *zoo_client_id(zhandle_t *zh);

ZOOAPI int zoo_recv_timeout(zhandle_t *zh);

ZOOAPI const void *zoo_get_context(zhandle_t *zh);

ZOOAPI void zoo_set_context(zhandle_t *zh, void *context);

/**
* \brief set a watcher function
* \return previous watcher function
*/
ZOOAPI watcher_fn zoo_set_watcher(zhandle_t *zh,watcher_fn newFn);

/**
* \brief Returns the events that zookeeper is interested in.
*
* \param zh the zookeeper handle obtained by a call to \ref zookeeper_init
* \param fd is the file descriptor of interest
* \param interest is an or of the ZOOKEEPER_WRITE and ZOOKEEPER_READ flags to
*    indicate the I/O of interest on fd.
* \param tv a timeout value to be used with select/poll system call
* \return a result code.
* ZOK - success
* ZBADARGUMENTS - invalid input parameters
* ZINVALIDSTATE - zhandle state is either ZOO_SESSION_EXPIRED_STATE or ZOO_AUTH_FAILED_STATE
* ZCONNECTIONLOSS - a network error occured while attempting to establish
* a connection to the server
* ZMARSHALLINGERROR - failed to marshall a request; possibly, out of memory
* ZOPERATIONTIMEOUT - hasn't received anything from the server for 2/3 of the
* timeout value specified in zookeeper_init()
* ZSYSTEMERROR -- a system (OS) error occured; it's worth checking errno to get details
*/
ZOOAPI int zookeeper_interest(zhandle_t *zh, int *fd, int *interest,
struct timeval *tv);

/**
* \brief Notifies zookeeper that an event of interest has happened.
*
* \param zh the zookeeper handle obtained by a call to \ref zookeeper_init
* \param events will be an OR of the ZOOKEEPER_WRITE and ZOOKEEPER_READ flags.
* \return a result code.
* ZOK - success
* ZBADARGUMENTS - invalid input parameters
* ZINVALIDSTATE - zhandle state is either ZOO_SESSION_EXPIRED_STATE or ZOO_AUTH_FAILED_STATE
* ZCONNECTIONLOSS - a network error occured while attempting to send request to server
* ZSESSIONEXPIRED - connection attempt failed -- the session's expired
* ZAUTHFAILED - authentication request failed, e.i. invalid credentials
* ZRUNTIMEINCONSISTENCY - a server response came out of order
* ZSYSTEMERROR -- a system (OS) error occured; it's worth checking errno to get details
* ZNOTHING -- not an error; simply indicates that there no more data from the server
*              to be processed (when called with ZOOKEEPER_READ flag).
*/
ZOOAPI int zookeeper_process(zhandle_t *zh, int events);
#endif

/**
* \brief signature of a completion function for a call that returns void.
*
* This method will be invoked at the end of a asynchronous call and also as
* a result of connection loss or timeout.
* \param rc the error code of the call. Connection loss/timeout triggers
* the completion with one of the following error codes:
* ZCONNECTIONLOSS -- lost connection to the server
* ZOPERATIONTIMEOUT -- connection timed out
* Data related events trigger the completion with error codes listed the
* Exceptions section of the documentation of the function that initiated the
* call. (Zero indicates call was successful.)
* \param data the pointer that was passed by the caller when the function
*   that this completion corresponds to was invoked. The programmer
*   is responsible for any memory freeing associated with the data
*   pointer.
*/
00416 typedef void (*void_completion_t)(int rc, const void *data);

/**
* \brief signature of a completion function that returns a Stat structure.
*
* This method will be invoked at the end of a asynchronous call and also as
* a result of connection loss or timeout.
* \param rc the error code of the call. Connection loss/timeout triggers
* the completion with one of the following error codes:
* ZCONNECTIONLOSS -- lost connection to the server
* ZOPERATIONTIMEOUT -- connection timed out
* Data related events trigger the completion with error codes listed the
* Exceptions section of the documentation of the function that initiated the
* call. (Zero indicates call was successful.)
* \param stat a pointer to the stat information for the node involved in
*   this function. If a non zero error code is returned, the content of
*   stat is undefined. The programmer is NOT responsible for freeing stat.
* \param data the pointer that was passed by the caller when the function
*   that this completion corresponds to was invoked. The programmer
*   is responsible for any memory freeing associated with the data
*   pointer.
*/
00438 typedef void (*stat_completion_t)(int rc, const struct Stat *stat,
const void *data);

/**
* \brief signature of a completion function that returns data.
*
* This method will be invoked at the end of a asynchronous call and also as
* a result of connection loss or timeout.
* \param rc the error code of the call. Connection loss/timeout triggers
* the completion with one of the following error codes:
* ZCONNECTIONLOSS -- lost connection to the server
* ZOPERATIONTIMEOUT -- connection timed out
* Data related events trigger the completion with error codes listed the
* Exceptions section of the documentation of the function that initiated the
* call. (Zero indicates call was successful.)
* \param value the value of the information returned by the asynchronous call.
*   If a non zero error code is returned, the content of value is undefined.
* \param value_len the number of bytes in value.
* \param stat a pointer to the stat information for the node involved in
*   this function. If a non zero error code is returned, the content of
*   stat is undefined. The programmer is NOT responsible for freeing stat.
* \param data the pointer that was passed by the caller when the function
*   that this completion corresponds to was invoked. The programmer
*   is responsible for any memory freeing associated with the data
*   pointer.
*/
00465 typedef void (*data_completion_t)(int rc, const char *value, int value_len,
const struct Stat *stat, const void *data);

/**
* \brief signature of a completion function that returns a list of strings.
*
* This method will be invoked at the end of a asynchronous call and also as
* a result of connection loss or timeout.
* \param rc the error code of the call. Connection loss/timeout triggers
* the completion with one of the following error codes:
* ZCONNECTIONLOSS -- lost connection to the server
* ZOPERATIONTIMEOUT -- connection timed out
* Data related events trigger the completion with error codes listed the
* Exceptions section of the documentation of the function that initiated the
* call. (Zero indicates call was successful.)
* \param strings a pointer to the structure containng the list of strings of the
*   names of the children of a node. If a non zero error code is returned,
*   the content of strings is undefined. The programmer is NOT responsible
* \param data the pointer that was passed by the caller when the function
*   that this completion corresponds to was invoked. The programmer
*   is responsible for any memory freeing associated with the data
*   pointer.
*/
00489 typedef void (*strings_completion_t)(int rc,
const struct String_vector *strings, const void *data);

/**
* \brief signature of a completion function that returns a list of strings.
*
* This method will be invoked at the end of a asynchronous call and also as
* a result of connection loss or timeout.
* \param rc the error code of the call. Connection loss/timeout triggers
* the completion with one of the following error codes:
* ZCONNECTIONLOSS -- lost connection to the server
* ZOPERATIONTIMEOUT -- connection timed out
* Data related events trigger the completion with error codes listed the
* Exceptions section of the documentation of the function that initiated the
* call. (Zero indicates call was successful.)
* \param value the value of the string returned.
* \param data the pointer that was passed by the caller when the function
*   that this completion corresponds to was invoked. The programmer
*   is responsible for any memory freeing associated with the data
*   pointer.
*/
typedef void
00511         (*string_completion_t)(int rc, const char *value, const void *data);

/**
* \brief signature of a completion function that returns an ACL.
*
* This method will be invoked at the end of a asynchronous call and also as
* a result of connection loss or timeout.
* \param rc the error code of the call. Connection loss/timeout triggers
* the completion with one of the following error codes:
* ZCONNECTIONLOSS -- lost connection to the server
* ZOPERATIONTIMEOUT -- connection timed out
* Data related events trigger the completion with error codes listed the
* Exceptions section of the documentation of the function that initiated the
* call. (Zero indicates call was successful.)
* \param acl a pointer to the structure containng the ACL of a node. If a non
*   zero error code is returned, the content of strings is undefined. The
* \param stat a pointer to the stat information for the node involved in
*   this function. If a non zero error code is returned, the content of
*   stat is undefined. The programmer is NOT responsible for freeing stat.
* \param data the pointer that was passed by the caller when the function
*   that this completion corresponds to was invoked. The programmer
*   is responsible for any memory freeing associated with the data
*   pointer.
*/
00536 typedef void (*acl_completion_t)(int rc, struct ACL_vector *acl,
struct Stat *stat, const void *data);

/**
* \brief get the state of the zookeeper connection.
*
* The return value will be one of the \ref State Consts.
*/
ZOOAPI int zoo_state(zhandle_t *zh);

/**
* \brief create a node.
*
* This method will create a node in ZooKeeper. A node can only be created if
* it does not already exists. The Create Flags affect the creation of nodes.
* If ZOO_EPHEMERAL flag is set, the node will automatically get removed if the
* client session goes away. If the ZOO_SEQUENCE flag is set, a unique
* monotonically increasing sequence number is appended to the path name.
*
* \param zh the zookeeper handle obtained by a call to \ref zookeeper_init
* \param path The name of the node. Expressed as a file name with slashes
* separating ancestors of the node.
* \param value The data to be stored in the node.
* \param valuelen The number of bytes in data.
* \param acl The initial ACL of the node. If null, the ACL of the parent will be
*    used.
* \param flags this parameter can be set to 0 for normal create or an OR
*    of the Create Flags
* \param completion the routine to invoke when the request completes. The completion
* will be triggered with one of the following codes passed in as the rc argument:
* ZOK operation completed succesfully
* ZNONODE the parent node does not exist.
* ZNODEEXISTS the node already exists
* ZNOAUTH the client does not have permission.
* ZNOCHILDRENFOREPHEMERALS cannot create children of ephemeral nodes.
* \param data The data that will be passed to the completion routine when the
* function completes.
* \return ZOK on success or one of the following errcodes on failure:
* ZBADARGUMENTS - invalid input parameters
* ZINVALIDSTATE - zhandle state is either ZOO_SESSION_EXPIRED_STATE or ZOO_AUTH_FAILED_STATE
* ZMARSHALLINGERROR - failed to marshall a request; possibly, out of memory
*/
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);

/**
* \brief delete a node in zookeeper.
*
* \param zh the zookeeper handle obtained by a call to \ref zookeeper_init
* \param path the name of the node. Expressed as a file name with slashes
* separating ancestors of the node.
* \param version the expected version of the node. The function will fail if the
*    actual version of the node does not match the expected version.
*  If -1 is used the version check will not take place.
* \param completion the routine to invoke when the request completes. The completion
* will be triggered with one of the following codes passed in as the rc argument:
* ZOK operation completed succesfully
* ZNONODE the node does not exist.
* ZNOAUTH the client does not have permission.
* ZBADVERSION expected version does not match actual version.
* ZNOTEMPTY children are present; node cannot be deleted.
* \param data the data that will be passed to the completion routine when
* the function completes.
* \return ZOK on success or one of the following errcodes on failure:
* ZBADARGUMENTS - invalid input parameters
* ZINVALIDSTATE - zhandle state is either ZOO_SESSION_EXPIRED_STATE or ZOO_AUTH_FAILED_STATE
* ZMARSHALLINGERROR - failed to marshall a request; possibly, out of memory
*/
ZOOAPI int zoo_adelete(zhandle_t *zh, const char *path, int version,
void_completion_t completion, const void *data);

/**
* \brief checks the existence of a node in zookeeper.
*
* \param zh the zookeeper handle obtained by a call to \ref zookeeper_init
* \param path the name of the node. Expressed as a file name with slashes
* separating ancestors of the node.
* \param watch if nonzero, a watch will be set at the server to notify the
* client if the node changes. The watch will be set even if the node does not
* exist. This allows clients to watch for nodes to appear.
* \param completion the routine to invoke when the request completes. The completion
* will be triggered with one of the following codes passed in as the rc argument:
* ZOK operation completed succesfully
* ZNONODE the node does not exist.
* ZNOAUTH the client does not have permission.
* \param data the data that will be passed to the completion routine when the
* function completes.
* \return ZOK on success or one of the following errcodes on failure:
* ZBADARGUMENTS - invalid input parameters
* ZINVALIDSTATE - zhandle state is either ZOO_SESSION_EXPIRED_STATE or ZOO_AUTH_FAILED_STATE
* ZMARSHALLINGERROR - failed to marshall a request; possibly, out of memory
*/
ZOOAPI int zoo_aexists(zhandle_t *zh, const char *path, int watch,
stat_completion_t completion, const void *data);

/**
* \brief checks the existence of a node in zookeeper.
*
* This function is similar to \ref zoo_axists except it allows one specify
* a watcher object - a function pointer and associated context. The function
* will be called once the watch has fired. The associated context data will be
* passed to the function as the watcher context parameter.
*
* \param zh the zookeeper handle obtained by a call to \ref zookeeper_init
* \param path the name of the node. Expressed as a file name with slashes
* separating ancestors of the node.
* \param watcher if non-null a watch will set on the specified znode on the server.
* The watch will be set even if the node does not exist. This allows clients
* to watch for nodes to appear.
* \param watcherCtx user specific data, will be passed to the watcher callback.
* Unlike the global context set by \ref zookeeper_init, this watcher context
* is associated with the given instance of the watcher only.
* \param completion the routine to invoke when the request completes. The completion
* will be triggered with one of the following codes passed in as the rc argument:
* ZOK operation completed succesfully
* ZNONODE the node does not exist.
* ZNOAUTH the client does not have permission.
* \param data the data that will be passed to the completion routine when the
* function completes.
* \return ZOK on success or one of the following errcodes on failure:
* ZBADARGUMENTS - invalid input parameters
* ZINVALIDSTATE - zhandle state is either ZOO_SESSION_EXPIRED_STATE or ZOO_AUTH_FAILED_STATE
* ZMARSHALLINGERROR - failed to marshall a request; possibly, out of memory
*/
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.
*
* \param zh the zookeeper handle obtained by a call to \ref zookeeper_init
* \param path the name of the node. Expressed as a file name with slashes
* separating ancestors of the node.
* \param watch if nonzero, a watch will be set at the server to notify
* the client if the node changes.
* \param completion the routine to invoke when the request completes. The completion
* will be triggered with one of the following codes passed in as the rc argument:
* ZOK operation completed succesfully
* ZNONODE the node does not exist.
* ZNOAUTH the client does not have permission.
* \param data the data that will be passed to the completion routine when
* the function completes.
* \return ZOK on success or one of the following errcodes on failure:
* ZBADARGUMENTS - invalid input parameters
* ZINVALIDSTATE - zhandle state is either in ZOO_SESSION_EXPIRED_STATE or ZOO_AUTH_FAILED_STATE
* ZMARSHALLINGERROR - failed to marshall a request; possibly, out of memory
*/
ZOOAPI int zoo_aget(zhandle_t *zh, const char *path, int watch,
data_completion_t completion, const void *data);

/**
* \brief gets the data associated with a node.
*
* This function is similar to \ref zoo_aget except it allows one specify
* a watcher object rather than a boolean watch flag.
*
* \param zh the zookeeper handle obtained by a call to \ref zookeeper_init
* \param path the name of the node. Expressed as a file name with slashes
* separating ancestors of the node.
* \param watcher if non-null, a watch will be set at the server to notify
* the client if the node changes.
* \param watcherCtx user specific data, will be passed to the watcher callback.
* Unlike the global context set by \ref zookeeper_init, this watcher context
* is associated with the given instance of the watcher only.
* \param completion the routine to invoke when the request completes. The completion
* will be triggered with one of the following codes passed in as the rc argument:
* ZOK operation completed succesfully
* ZNONODE the node does not exist.
* ZNOAUTH the client does not have permission.
* \param data the data that will be passed to the completion routine when
* the function completes.
* \return ZOK on success or one of the following errcodes on failure:
* ZBADARGUMENTS - invalid input parameters
* ZINVALIDSTATE - zhandle state is either in ZOO_SESSION_EXPIRED_STATE or ZOO_AUTH_FAILED_STATE
* ZMARSHALLINGERROR - failed to marshall a request; possibly, out of memory
*/
ZOOAPI int zoo_awget(zhandle_t *zh, const char *path,
watcher_fn watcher, void* watcherCtx,
data_completion_t completion, const void *data);

/**
* \brief sets the data associated with a node.
*
* \param zh the zookeeper handle obtained by a call to \ref zookeeper_init
* \param path the name of the node. Expressed as a file name with slashes
* separating ancestors of the node.
* \param buffer the buffer holding data to be written to the node.
* \param buflen the number of bytes from buffer to write.
* \param version the expected version of the node. The function will fail if
* the actual version of the node does not match the expected version. If -1 is
* used the version check will not take place. * completion: If null,
* the function will execute synchronously. Otherwise, the function will return
* immediately and invoke the completion routine when the request completes.
* \param completion the routine to invoke when the request completes. The completion
* will be triggered with one of the following codes passed in as the rc argument:
* ZOK operation completed succesfully
* ZNONODE the node does not exist.
* ZNOAUTH the client does not have permission.
* ZBADVERSION expected version does not match actual version.
* \param data the data that will be passed to the completion routine when
* the function completes.
* \return ZOK on success or one of the following errcodes on failure:
* ZBADARGUMENTS - invalid input parameters
* ZINVALIDSTATE - zhandle state is either ZOO_SESSION_EXPIRED_STATE or ZOO_AUTH_FAILED_STATE
* ZMARSHALLINGERROR - failed to marshall a request; possibly, out of memory
*/
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 lists the children of a node.
*
* \param zh the zookeeper handle obtained by a call to \ref zookeeper_init
* \param path the name of the node. Expressed as a file name with slashes
* separating ancestors of the node.
* \param watch if nonzero, a watch will be set at the server to notify
* the client if the node changes.
* \param completion the routine to invoke when the request completes. The completion
* will be triggered with one of the following codes passed in as the rc argument:
* ZOK operation completed succesfully
* ZNONODE the node does not exist.
* ZNOAUTH the client does not have permission.
* \param data the data that will be passed to the completion routine when
* the function completes.
* \return ZOK on success or one of the following errcodes on failure:
* ZBADARGUMENTS - invalid input parameters
* ZINVALIDSTATE - zhandle state is either ZOO_SESSION_EXPIRED_STATE or ZOO_AUTH_FAILED_STATE
* ZMARSHALLINGERROR - failed to marshall a request; possibly, out of memory
*/
ZOOAPI int zoo_aget_children(zhandle_t *zh, const char *path, int watch,
strings_completion_t completion, const void *data);

/**
* \brief lists the children of a node.
*
* This function is similar to \ref zoo_aget_children except it allows one specify
* a watcher object rather than a boolean watch flag.
*
* \param zh the zookeeper handle obtained by a call to \ref zookeeper_init
* \param path the name of the node. Expressed as a file name with slashes
* separating ancestors of the node.
* \param watcher if non-null, a watch will be set at the server to notify
* the client if the node changes.
* \param watcherCtx user specific data, will be passed to the watcher callback.
* Unlike the global context set by \ref zookeeper_init, this watcher context
* is associated with the given instance of the watcher only.
* \param completion the routine to invoke when the request completes. The completion
* will be triggered with one of the following codes passed in as the rc argument:
* ZOK operation completed succesfully
* ZNONODE the node does not exist.
* ZNOAUTH the client does not have permission.
* \param data the data that will be passed to the completion routine when
* the function completes.
* \return ZOK on success or one of the following errcodes on failure:
* ZBADARGUMENTS - invalid input parameters
* ZINVALIDSTATE - zhandle state is either ZOO_SESSION_EXPIRED_STATE or ZOO_AUTH_FAILED_STATE
* ZMARSHALLINGERROR - failed to marshall a request; possibly, out of memory
*/
ZOOAPI int zoo_awget_children(zhandle_t *zh, const char *path,
watcher_fn watcher, void* watcherCtx,
strings_completion_t completion, const void *data);

/**
*
* \param zh the zookeeper handle obtained by a call to \ref zookeeper_init
* \param path the name of the node. Expressed as a file name with slashes
* separating ancestors of the node.
* \param completion the routine to invoke when the request completes. The completion
* will be triggered with one of the following codes passed in as the rc argument:
* ZOK operation completed succesfully
* ZNONODE the node does not exist.
* ZNOAUTH the client does not have permission.
* \param data the data that will be passed to the completion routine when
* the function completes.
* \return ZOK on success or one of the following errcodes on failure:
* ZBADARGUMENTS - invalid input parameters
* ZINVALIDSTATE - zhandle state is either ZOO_SESSION_EXPIRED_STATE or ZOO_AUTH_FAILED_STATE
* ZMARSHALLINGERROR - failed to marshall a request; possibly, out of memory
*/

ZOOAPI int zoo_async(zhandle_t *zh, const char *path,
string_completion_t completion, const void *data);

/**
* \brief gets the acl associated with a node.
*
* \param zh the zookeeper handle obtained by a call to \ref zookeeper_init
* \param path the name of the node. Expressed as a file name with slashes
* separating ancestors of the node.
* \param completion the routine to invoke when the request completes. The completion
* will be triggered with one of the following codes passed in as the rc argument:
* ZOK operation completed succesfully
* ZNONODE the node does not exist.
* ZNOAUTH the client does not have permission.
* \param data the data that will be passed to the completion routine when
* the function completes.
* \return ZOK on success or one of the following errcodes on failure:
* ZBADARGUMENTS - invalid input parameters
* ZINVALIDSTATE - zhandle state is either ZOO_SESSION_EXPIRED_STATE or ZOO_AUTH_FAILED_STATE
* ZMARSHALLINGERROR - failed to marshall a request; possibly, out of memory
*/
ZOOAPI int zoo_aget_acl(zhandle_t *zh, const char *path, acl_completion_t completion,
const void *data);

/**
* \brief sets the acl associated with a node.
*
* \param zh the zookeeper handle obtained by a call to \ref zookeeper_init
* \param path the name of the node. Expressed as a file name with slashes
* separating ancestors of the node.
* \param buffer the buffer holding the acls to be written to the node.
* \param buflen the number of bytes from buffer to write.
* \param completion the routine to invoke when the request completes. The completion
* will be triggered with one of the following codes passed in as the rc argument:
* ZOK operation completed succesfully
* ZNONODE the node does not exist.
* ZNOAUTH the client does not have permission.
* ZINVALIDACL invalid ACL specified
* ZBADVERSION expected version does not match actual version.
* \param data the data that will be passed to the completion routine when
* the function completes.
* \return ZOK on success or one of the following errcodes on failure:
* ZBADARGUMENTS - invalid input parameters
* ZINVALIDSTATE - zhandle state is either ZOO_SESSION_EXPIRED_STATE or ZOO_AUTH_FAILED_STATE
* ZMARSHALLINGERROR - failed to marshall a request; possibly, out of memory
*/
ZOOAPI int zoo_aset_acl(zhandle_t *zh, const char *path, int version,
struct ACL_vector *acl, void_completion_t, const void *data);

/**
* \brief return an error string.
*
* \param return code
* \return string corresponding to the return code
*/
ZOOAPI const char* zerror(int c);

/**
* \brief specify application credentials.
*
* The application calls this function to specify its credentials for purposes
* of authentication. The server will use the security provider specified by
* the scheme parameter to authenticate the client connection. If the
* authentication request has failed:
* - the server connection is dropped
* - the watcher is called with the ZOO_AUTH_FAILED_STATE value as the state
* parameter.
* \param zh the zookeeper handle obtained by a call to \ref zookeeper_init
* \param scheme the id of authentication scheme. Natively supported:
* \param cert application credentials. The actual value depends on the scheme.
* \param certLen the length of the data parameter
* \param completion the routine to invoke when the request completes. One of
* the following result codes may be passed into the completion callback:
* ZOK operation completed successfully
* ZAUTHFAILED authentication failed
* \param data the data that will be passed to the completion routine when the
* function completes.
* \return ZOK on success or one of the following errcodes on failure:
* ZBADARGUMENTS - invalid input parameters
* ZINVALIDSTATE - zhandle state is either ZOO_SESSION_EXPIRED_STATE or ZOO_AUTH_FAILED_STATE
* ZMARSHALLINGERROR - failed to marshall a request; possibly, out of memory
* ZSYSTEMERROR - a system error occured
*/
ZOOAPI int zoo_add_auth(zhandle_t *zh,const char* scheme,const char* cert,
int certLen, void_completion_t completion, const void *data);

/**
* \brief checks if the current zookeeper connection state can't be recovered.
*
*  The application must close the zhandle and try to reconnect.
*
* \param zh the zookeeper handle (see \ref zookeeper_init)
* \return ZINVALIDSTATE if connection is unrecoverable
*/
ZOOAPI int is_unrecoverable(zhandle_t *zh);

/**
* \brief sets the debugging level for the library
*/
ZOOAPI void zoo_set_debug_level(ZooLogLevel logLevel);

/**
* \brief sets the stream to be used by the library for logging
*
* The zookeeper library uses stderr as its default log stream. Application
* must make sure the stream is writable. Passing in NULL resets the stream
* to its default value (stderr).
*/
ZOOAPI void zoo_set_log_stream(FILE* logStream);

/**
* \brief enable/disable quorum endpoint order randomization
*
* If passed a non-zero value, will make the client connect to quorum peers
* in the order as specified in the zookeeper_init() call.
* A zero value causes zookeeper_init() to permute the peer endpoints
* which is good for more even client connection distribution among the
* quorum peers.
*/
ZOOAPI void zoo_deterministic_conn_order(int yesOrNo);

/**
* \brief create a node synchronously.
*
* This method will create a node in ZooKeeper. A node can only be created if
* it does not already exists. The Create Flags affect the creation of nodes.
* If ZOO_EPHEMERAL flag is set, the node will automatically get removed if the
* client session goes away. If the ZOO_SEQUENCE flag is set, a unique
* monotonically increasing sequence number is appended to the path name.
*
* \param zh the zookeeper handle obtained by a call to \ref zookeeper_init
* \param path The name of the node. Expressed as a file name with slashes
* separating ancestors of the node.
* \param value The data to be stored in the node.
* \param valuelen The number of bytes in data. To set the data to be NULL use
* value as NULL and valuelen as -1.
* \param acl The initial ACL of the node. If null, the ACL of the parent will be
*    used.
* \param flags this parameter can be set to 0 for normal create or an OR
*    of the Create Flags
* \param path_buffer Buffer which will be filled with the path of the
*    new node (this might be different than the supplied path
*    because of the ZOO_SEQUENCE flag).  The path string will always be
*    null-terminated.
* \param path_buffer_len Size of path buffer; if the path of the new
*    node (including space for the null terminator) exceeds the buffer size,
*    the path string will be truncated to fit.  The actual path of the
*    new node in the server will not be affected by the truncation.
*    The path string will always be null-terminated.
* \return  one of the following codes are returned:
* ZOK operation completed succesfully
* ZNONODE the parent node does not exist.
* ZNODEEXISTS the node already exists
* ZNOAUTH the client does not have permission.
* ZNOCHILDRENFOREPHEMERALS cannot create children of ephemeral nodes.
* ZBADARGUMENTS - invalid input parameters
* ZINVALIDSTATE - zhandle state is either ZOO_SESSION_EXPIRED_STATE or ZOO_AUTH_FAILED_STATE
* ZMARSHALLINGERROR - failed to marshall a request; possibly, out of memory
*/
ZOOAPI int zoo_create(zhandle_t *zh, const char *path, const char *value,
int valuelen, const struct ACL_vector *acl, int flags,
char *path_buffer, int path_buffer_len);

/**
* \brief delete a node in zookeeper synchronously.
*
* \param zh the zookeeper handle obtained by a call to \ref zookeeper_init
* \param path the name of the node. Expressed as a file name with slashes
* separating ancestors of the node.
* \param version the expected version of the node. The function will fail if the
*    actual version of the node does not match the expected version.
*  If -1 is used the version check will not take place.
* \return one of the following values is returned.
* ZOK operation completed succesfully
* ZNONODE the node does not exist.
* ZNOAUTH the client does not have permission.
* ZBADVERSION expected version does not match actual version.
* ZNOTEMPTY children are present; node cannot be deleted.
* ZBADARGUMENTS - invalid input parameters
* ZINVALIDSTATE - zhandle state is either ZOO_SESSION_EXPIRED_STATE or ZOO_AUTH_FAILED_STATE
* ZMARSHALLINGERROR - failed to marshall a request; possibly, out of memory
*/
ZOOAPI int zoo_delete(zhandle_t *zh, const char *path, int version);

/**
* \brief checks the existence of a node in zookeeper synchronously.
*
* \param zh the zookeeper handle obtained by a call to \ref zookeeper_init
* \param path the name of the node. Expressed as a file name with slashes
* separating ancestors of the node.
* \param watch if nonzero, a watch will be set at the server to notify the
* client if the node changes. The watch will be set even if the node does not
* exist. This allows clients to watch for nodes to appear.
* \param the return stat value of the node.
* \return  return code of the function call.
* ZOK operation completed succesfully
* ZNONODE the node does not exist.
* ZNOAUTH the client does not have permission.
* ZBADARGUMENTS - invalid input parameters
* ZINVALIDSTATE - zhandle state is either ZOO_SESSION_EXPIRED_STATE or ZOO_AUTH_FAILED_STATE
* ZMARSHALLINGERROR - failed to marshall a request; possibly, out of memory
*/
ZOOAPI int zoo_exists(zhandle_t *zh, const char *path, int watch, struct Stat *stat);

/**
* \brief checks the existence of a node in zookeeper synchronously.
*
* This function is similar to \ref zoo_exists except it allows one specify
* a watcher object rather than a boolean watch flag.
*
* \param zh the zookeeper handle obtained by a call to \ref zookeeper_init
* \param path the name of the node. Expressed as a file name with slashes
* separating ancestors of the node.
* \param watcher if non-null a watch will set on the specified znode on the server.
* The watch will be set even if the node does not exist. This allows clients
* to watch for nodes to appear.
* \param watcherCtx user specific data, will be passed to the watcher callback.
* Unlike the global context set by \ref zookeeper_init, this watcher context
* is associated with the given instance of the watcher only.
* \param the return stat value of the node.
* \return  return code of the function call.
* ZOK operation completed succesfully
* ZNONODE the node does not exist.
* ZNOAUTH the client does not have permission.
* ZBADARGUMENTS - invalid input parameters
* ZINVALIDSTATE - zhandle state is either ZOO_SESSION_EXPIRED_STATE or ZOO_AUTH_FAILED_STATE
* ZMARSHALLINGERROR - failed to marshall a request; possibly, out of memory
*/
ZOOAPI int zoo_wexists(zhandle_t *zh, const char *path,
watcher_fn watcher, void* watcherCtx, struct Stat *stat);

/**
* \brief gets the data associated with a node synchronously.
*
* \param zh the zookeeper handle obtained by a call to \ref zookeeper_init
* \param path the name of the node. Expressed as a file name with slashes
* separating ancestors of the node.
* \param watch if nonzero, a watch will be set at the server to notify
* the client if the node changes.
* \param buffer the buffer holding the node data returned by the server
* \param buffer_len is the size of the buffer pointed to by the buffer parameter.
* It'll be set to the actual data length upon return. If the data is NULL, length is -1.
* \param stat if not NULL, will hold the value of stat for the path on return.
* \return return value of the function call.
* ZOK operation completed succesfully
* ZNONODE the node does not exist.
* ZNOAUTH the client does not have permission.
* ZBADARGUMENTS - invalid input parameters
* ZINVALIDSTATE - zhandle state is either in ZOO_SESSION_EXPIRED_STATE or ZOO_AUTH_FAILED_STATE
* ZMARSHALLINGERROR - failed to marshall a request; possibly, out of memory
*/
ZOOAPI int zoo_get(zhandle_t *zh, const char *path, int watch, char *buffer,
int* buffer_len, struct Stat *stat);

/**
* \brief gets the data associated with a node synchronously.
*
* This function is similar to \ref zoo_get except it allows one specify
* a watcher object rather than a boolean watch flag.
*
* \param zh the zookeeper handle obtained by a call to \ref zookeeper_init
* \param path the name of the node. Expressed as a file name with slashes
* separating ancestors of the node.
* \param watcher if non-null, a watch will be set at the server to notify
* the client if the node changes.
* \param watcherCtx user specific data, will be passed to the watcher callback.
* Unlike the global context set by \ref zookeeper_init, this watcher context
* is associated with the given instance of the watcher only.
* \param buffer the buffer holding the node data returned by the server
* \param buffer_len is the size of the buffer pointed to by the buffer parameter.
* It'll be set to the actual data length upon return. If the data is NULL, length is -1.
* \param stat if not NULL, will hold the value of stat for the path on return.
* \return return value of the function call.
* ZOK operation completed succesfully
* ZNONODE the node does not exist.
* ZNOAUTH the client does not have permission.
* ZBADARGUMENTS - invalid input parameters
* ZINVALIDSTATE - zhandle state is either in ZOO_SESSION_EXPIRED_STATE or ZOO_AUTH_FAILED_STATE
* ZMARSHALLINGERROR - failed to marshall a request; possibly, out of memory
*/
ZOOAPI int zoo_wget(zhandle_t *zh, const char *path,
watcher_fn watcher, void* watcherCtx,
char *buffer, int* buffer_len, struct Stat *stat);

/**
* \brief sets the data associated with a node. See zoo_set2 function if
* you require access to the stat information associated with the znode.
*
* \param zh the zookeeper handle obtained by a call to \ref zookeeper_init
* \param path the name of the node. Expressed as a file name with slashes
* separating ancestors of the node.
* \param buffer the buffer holding data to be written to the node.
* \param buflen the number of bytes from buffer to write. To set NULL as data
* use buffer as NULL and buflen as -1.
* \param version the expected version of the node. The function will fail if
* the actual version of the node does not match the expected version. If -1 is
* used the version check will not take place.
* \return the return code for the function call.
* ZOK operation completed succesfully
* ZNONODE the node does not exist.
* ZNOAUTH the client does not have permission.
* ZBADVERSION expected version does not match actual version.
* ZBADARGUMENTS - invalid input parameters
* ZINVALIDSTATE - zhandle state is either ZOO_SESSION_EXPIRED_STATE or ZOO_AUTH_FAILED_STATE
* ZMARSHALLINGERROR - failed to marshall a request; possibly, out of memory
*/
ZOOAPI int zoo_set(zhandle_t *zh, const char *path, const char *buffer,
int buflen, int version);

/**
* \brief sets the data associated with a node. This function is the same
* as zoo_set except that it also provides access to stat information
* associated with the znode.
*
* \param zh the zookeeper handle obtained by a call to \ref zookeeper_init
* \param path the name of the node. Expressed as a file name with slashes
* separating ancestors of the node.
* \param buffer the buffer holding data to be written to the node.
* \param buflen the number of bytes from buffer to write. To set NULL as data
* use buffer as NULL and buflen as -1.
* \param version the expected version of the node. The function will fail if
* the actual version of the node does not match the expected version. If -1 is
* used the version check will not take place.
* \param stat if not NULL, will hold the value of stat for the path on return.
* \return the return code for the function call.
* ZOK operation completed succesfully
* ZNONODE the node does not exist.
* ZNOAUTH the client does not have permission.
* ZBADVERSION expected version does not match actual version.
* ZBADARGUMENTS - invalid input parameters
* ZINVALIDSTATE - zhandle state is either ZOO_SESSION_EXPIRED_STATE or ZOO_AUTH_FAILED_STATE
* ZMARSHALLINGERROR - failed to marshall a request; possibly, out of memory
*/
ZOOAPI int zoo_set2(zhandle_t *zh, const char *path, const char *buffer,
int buflen, int version, struct Stat *stat);

/**
* \brief lists the children of a node synchronously.
*
* \param zh the zookeeper handle obtained by a call to \ref zookeeper_init
* \param path the name of the node. Expressed as a file name with slashes
* separating ancestors of the node.
* \param watch if nonzero, a watch will be set at the server to notify
* the client if the node changes.
* \param strings return value of children paths.
* \return the return code of the function.
* ZOK operation completed succesfully
* ZNONODE the node does not exist.
* ZNOAUTH the client does not have permission.
* ZBADARGUMENTS - invalid input parameters
* ZINVALIDSTATE - zhandle state is either ZOO_SESSION_EXPIRED_STATE or ZOO_AUTH_FAILED_STATE
* ZMARSHALLINGERROR - failed to marshall a request; possibly, out of memory
*/
ZOOAPI int zoo_get_children(zhandle_t *zh, const char *path, int watch,
struct String_vector *strings);

/**
* \brief lists the children of a node synchronously.
*
* This function is similar to \ref zoo_get_children except it allows one specify
* a watcher object rather than a boolean watch flag.
*
* \param zh the zookeeper handle obtained by a call to \ref zookeeper_init
* \param path the name of the node. Expressed as a file name with slashes
* separating ancestors of the node.
* \param watcher if non-null, a watch will be set at the server to notify
* the client if the node changes.
* \param watcherCtx user specific data, will be passed to the watcher callback.
* Unlike the global context set by \ref zookeeper_init, this watcher context
* is associated with the given instance of the watcher only.
* \param strings return value of children paths.
* \return the return code of the function.
* ZOK operation completed succesfully
* ZNONODE the node does not exist.
* ZNOAUTH the client does not have permission.
* ZBADARGUMENTS - invalid input parameters
* ZINVALIDSTATE - zhandle state is either ZOO_SESSION_EXPIRED_STATE or ZOO_AUTH_FAILED_STATE
* ZMARSHALLINGERROR - failed to marshall a request; possibly, out of memory
*/
ZOOAPI int zoo_wget_children(zhandle_t *zh, const char *path,
watcher_fn watcher, void* watcherCtx,
struct String_vector *strings);

/**
* \brief gets the acl associated with a node synchronously.
*
* \param zh the zookeeper handle obtained by a call to \ref zookeeper_init
* \param path the name of the node. Expressed as a file name with slashes
* separating ancestors of the node.
* \param acl the return value of acls on the path.
* \param stat returns the stat of the path specified.
* \return the return code for the function call.
* ZOK operation completed succesfully
* ZNONODE the node does not exist.
* ZNOAUTH the client does not have permission.
* ZBADARGUMENTS - invalid input parameters
* ZINVALIDSTATE - zhandle state is either ZOO_SESSION_EXPIRED_STATE or ZOO_AUTH_FAILED_STATE
* ZMARSHALLINGERROR - failed to marshall a request; possibly, out of memory
*/
ZOOAPI int zoo_get_acl(zhandle_t *zh, const char *path, struct ACL_vector *acl,
struct Stat *stat);

/**
* \brief sets the acl associated with a node synchronously.
*
* \param zh the zookeeper handle obtained by a call to \ref zookeeper_init
* \param path the name of the node. Expressed as a file name with slashes
* separating ancestors of the node.
* \param version the expected version of the path.
* \param acl the acl to be set on the path.
* \return the return code for the function call.
* ZOK operation completed succesfully
* ZNONODE the node does not exist.
* ZNOAUTH the client does not have permission.
* ZINVALIDACL invalid ACL specified
* ZBADVERSION expected version does not match actual version.
* ZBADARGUMENTS - invalid input parameters
* ZINVALIDSTATE - zhandle state is either ZOO_SESSION_EXPIRED_STATE or ZOO_AUTH_FAILED_STATE
* ZMARSHALLINGERROR - failed to marshall a request; possibly, out of memory
*/
ZOOAPI int zoo_set_acl(zhandle_t *zh, const char *path, int version,
const struct ACL_vector *acl);

#ifdef __cplusplus
}
#endif

#endif /*ZOOKEEPER_H_*/


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