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4/* */
5/* X r d O u c C a l l B a c k . h h */
6/* */
7/* (c) 2011 by the Board of Trustees of the Leland Stanford, Jr., University */
8/* All Rights Reserved */
9/* Produced by Andrew Hanushevsky for Stanford University under contract */
10/* DE-AC02-76-SFO0515 with the Department of Energy */
11/* */
12/* This file is part of the XRootD software suite. */
13/* */
14/* XRootD is free software: you can redistribute it and/or modify it under */
15/* the terms of the GNU Lesser General Public License as published by the */
16/* Free Software Foundation, either version 3 of the License, or (at your */
17/* option) any later version. */
18/* */
19/* XRootD is distributed in the hope that it will be useful, but WITHOUT */
20/* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or */
21/* FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public */
22/* License for more details. */
23/* */
24/* You should have received a copy of the GNU Lesser General Public License */
25/* along with XRootD in a file called COPYING.LESSER (LGPL license) and file */
26/* COPYING (GPL license). If not, see <http://www.gnu.org/licenses/>. */
27/* */
28/* The copyright holder's institutional names and contributor's names may not */
29/* be used to endorse or promote products derived from this software without */
30/* specific prior written permission of the institution or contributor. */
36/* The XrdOucCallBack object encapsulates the vagaries of handling callbacks
37 in the xrootd framework; where callbacks are allowed. Once a callback is
38 successfully established using Init() this object should not be deleted
39 until Reply() of Cancel() is called. The destructor automatically calls
40 Cancel() is a callback is outstanding. The object may be reused after
41 Cancel() or Reply is called. See warnings on Init() and Cancel().
43 This object is not MT-safe and must be used in a serial fashion.
50/* Allowed() tell you whether or not am XrdOucErrInfo object has been setup to
51 allow callbacks. You should test this before assuming you can use
52 the object to effect a callback.
54 Returns: True - if a callback is allowed.
55 False - otherwise.
57static int Allowed(XrdOucErrInfo *eInfo) {return eInfo->getErrCB() != 0;}
59/* Cancel() cancels the callback. If no callback is oustanding, it does
60 nothing. Otherwise, the associated endpoint is told to retry
61 whatever operation caused the callback to be setup. Warning,
62 calling Cancel() or deleting this object after calling Init()
63 but not effecting a callback response will cause the calling
64 thread to hang!
66 void Cancel();
68/* Init() sets up a call back using the provided XrdOucErrInfo object.
69 You must successfully call Init() before calling Reply()!
70 Warning, once you cann Init() you *must* effect a callback
71 response; otherwise, it is likely a subsequent thread using
72 this object will hang!
74 Returns: True - if a callback was set up.
75 False - otherwise (i.e., object does not allow callbacks).
77 int Init(XrdOucErrInfo *eInfo);
79/* Reply() sends the specified results to the endpoint associated with the
80 callback esablished by Init(). The parameters are:
81 retVal - The value you would have synchrnously returned.
82 eValue - The numeric value that would have been returned in the
83 original XrdOucErrInfo object.
84 eText - The character string that would have been returned in the
85 original XrdOucErrInfo object.
86 Path - Optional path related to the reply. It is passed to the
87 callback effector and is used for tracing & monitoring.
89 Returns: True - if a callback was initiated.
90 False - callback failed; likely Init() was not successfully called.
92 int Reply(int retVal, int eValue, const char *eText,
93 const char *Path=0);
95 XrdOucCallBack() : Next(0), cbSync(0), cbArg(0), cbObj(0) {}
98// The following is a handy pointer to allow for linking these objects together
103void Done(int &Result,XrdOucErrInfo *eInfo,const char *Path=0)
104{ (void)Result; (void)eInfo; (void)Path; cbSync.Post();}
105int Same(unsigned long long arg1, unsigned long long arg2)
106{ (void)arg1; (void)arg2; return 0;}
109unsigned long long cbArg;
111char UserID[64];
Definition XrdOucCallBack.hh:47
int Reply(int retVal, int eValue, const char *eText, const char *Path=0)
int Init(XrdOucErrInfo *eInfo)
char UserID[64]
Definition XrdOucCallBack.hh:111
XrdSysSemaphore cbSync
Definition XrdOucCallBack.hh:108
unsigned long long cbArg
Definition XrdOucCallBack.hh:109
Definition XrdOucCallBack.hh:96
Definition XrdOucCallBack.hh:95
int Same(unsigned long long arg1, unsigned long long arg2)
Definition XrdOucCallBack.hh:105
void Done(int &Result, XrdOucErrInfo *eInfo, const char *Path=0)
Definition XrdOucCallBack.hh:103
static int Allowed(XrdOucErrInfo *eInfo)
Definition XrdOucCallBack.hh:57
XrdOucCallBack * Next
Definition XrdOucCallBack.hh:100
XrdOucEICB * cbObj
Definition XrdOucCallBack.hh:110
Definition XrdOucErrInfo.hh:483
Definition XrdOucErrInfo.hh:101
XrdOucEICB * getErrCB()
Definition XrdOucErrInfo.hh:224
Definition XrdSysPthread.hh:494
void Post()
Definition XrdSysPthread.hh:505