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XrdOucCallBack.hh
Go to the documentation of this file.
#ifndef __XRDOUCCALLBACK__HH_
#define __XRDOUCCALLBACK__HH_
/******************************************************************************/
/* */
/* X r d O u c C a l l B a c k . h h */
/* */
/* (c) 2011 by the Board of Trustees of the Leland Stanford, Jr., University */
/* All Rights Reserved */
/* Produced by Andrew Hanushevsky for Stanford University under contract */
/* DE-AC02-76-SFO0515 with the Department of Energy */
/* */
/* This file is part of the XRootD software suite. */
/* */
/* XRootD is free software: you can redistribute it and/or modify it under */
/* the terms of the GNU Lesser General Public License as published by the */
/* Free Software Foundation, either version 3 of the License, or (at your */
/* option) any later version. */
/* */
/* XRootD is distributed in the hope that it will be useful, but WITHOUT */
/* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or */
/* FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public */
/* License for more details. */
/* */
/* You should have received a copy of the GNU Lesser General Public License */
/* along with XRootD in a file called COPYING.LESSER (LGPL license) and file */
/* COPYING (GPL license). If not, see <http://www.gnu.org/licenses/>. */
/* */
/* The copyright holder's institutional names and contributor's names may not */
/* be used to endorse or promote products derived from this software without */
/* specific prior written permission of the institution or contributor. */
/******************************************************************************/
#include "XrdOuc/XrdOucErrInfo.hh"
#include "XrdSys/XrdSysPthread.hh"
/* The XrdOucCallBack object encapsulates the vagaries of handling callbacks
in the xrootd framework; where callbacks are allowed. Once a callback is
successfully established using Init() this object should not be deleted
until Reply() of Cancel() is called. The destructor automatically calls
Cancel() is a callback is outstanding. The object may be reused after
Cancel() or Reply is called. See warnings on Init() and Cancel().
This object is not MT-safe and must be used in a serial fashion.
*/
class XrdOucCallBack : public XrdOucEICB
{
public:
/* Allowed() tell you whether or not am XrdOucErrInfo object has been setup to
allow callbacks. You should test this before assuming you can use
the object to effect a callback.
Returns: True - if a callback is allowed.
False - otherwise.
*/
static int Allowed(XrdOucErrInfo *eInfo) {return eInfo->getErrCB() != 0;}
/* Cancel() cancels the callback. If no callback is oustanding, it does
nothing. Otherwise, the associated endpoint is told to retry
whatever operation caused the callback to be setup. Warning,
calling Cancel() or deleting this object after calling Init()
but not effecting a callback response will cause the calling
thread to hang!
*/
void Cancel();
/* Init() sets up a call back using the provided XrdOucErrInfo object.
You must successfully call Init() before calling Reply()!
Warning, once you cann Init() you *must* effect a callback
response; otherwise, it is likely a subsequent thread using
this object will hang!
Returns: True - if a callback was set up.
False - otherwise (i.e., object does not allow callbacks).
*/
int Init(XrdOucErrInfo *eInfo);
/* Reply() sends the specified results to the endpoint associated with the
callback esablished by Init(). The parameters are:
retVal - The value you would have synchrnously returned.
eValue - The numeric value that would have been returned in the
original XrdOucErrInfo object.
eText - The character string that would have been returned in the
original XrdOucErrInfo object.
Path - Optional path related to the reply. It is passed to the
callback effector and is used for tracing & monitoring.
Returns: True - if a callback was initiated.
False - callback failed; likely Init() was not successfully called.
*/
int Reply(int retVal, int eValue, const char *eText,
const char *Path=0);
XrdOucCallBack() : Next(0), cbSync(0), cbArg(0), cbObj(0) {}
~XrdOucCallBack() {if (cbObj) Cancel();}
// The following is a handy pointer to allow for linking these objects together
//
XrdOucCallBack *Next;
private:
void Done(int &Result,XrdOucErrInfo *eInfo,const char *Path=0)
{ (void)Result; (void)eInfo; (void)Path; cbSync.Post();}
int Same(unsigned long long arg1, unsigned long long arg2)
{ (void)arg1; (void)arg2; return 0;}
XrdSysSemaphore cbSync;
unsigned long long cbArg;
XrdOucEICB *cbObj;
char UserID[64];
};
#endif
XrdOucErrInfo.hh
Path
XrdOucString Path
Definition XrdSecpwdSrvAdmin.cc:160
XrdSysPthread.hh
XrdOucCallBack::Reply
int Reply(int retVal, int eValue, const char *eText, const char *Path=0)
Definition XrdOucCallBack.cc:81
XrdOucCallBack::Cancel
void Cancel()
Definition XrdOucCallBack.cc:38
XrdOucCallBack::Init
int Init(XrdOucErrInfo *eInfo)
Definition XrdOucCallBack.cc:51
XrdOucCallBack::~XrdOucCallBack
~XrdOucCallBack()
Definition XrdOucCallBack.hh:96
XrdOucCallBack::XrdOucCallBack
XrdOucCallBack()
Definition XrdOucCallBack.hh:95
XrdOucCallBack::Allowed
static int Allowed(XrdOucErrInfo *eInfo)
Definition XrdOucCallBack.hh:57
XrdOucCallBack::Next
XrdOucCallBack * Next
Definition XrdOucCallBack.hh:100
XrdOucEICB::XrdOucEICB
XrdOucEICB()
Constructor and destructor.
Definition XrdOucErrInfo.hh:522
XrdOucErrInfo
Definition XrdOucErrInfo.hh:101
XrdOucErrInfo::getErrCB
XrdOucEICB * getErrCB()
Definition XrdOucErrInfo.hh:224