XRootD
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XrdSsiEvent.cc
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1/******************************************************************************/
2/* */
3/* X r d S s i E v e n t . c c */
4/* */
5/* (c) 2015 by the Board of Trustees of the Leland Stanford, Jr., University */
6/* Produced by Andrew Hanushevsky for Stanford University under contract */
7/* DE-AC02-76-SFO0515 with the Department of Energy */
8/* */
9/* This file is part of the XRootD software suite. */
10/* */
11/* XRootD is free software: you can redistribute it and/or modify it under */
12/* the terms of the GNU Lesser General Public License as published by the */
13/* Free Software Foundation, either version 3 of the License, or (at your */
14/* option) any later version. */
15/* */
16/* XRootD is distributed in the hope that it will be useful, but WITHOUT */
17/* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or */
18/* FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public */
19/* License for more details. */
20/* */
21/* You should have received a copy of the GNU Lesser General Public License */
22/* along with XRootD in a file called COPYING.LESSER (LGPL license) and file */
23/* COPYING (GPL license). If not, see <http://www.gnu.org/licenses/>. */
24/* */
25/* The copyright holder's institutional names and contributor's names may not */
26/* be used to endorse or promote products derived from this software without */
27/* specific prior written permission of the institution or contributor. */
28/******************************************************************************/
29
30#include "XrdSsi/XrdSsiEvent.hh"
31#include "XrdSsi/XrdSsiTrace.hh"
32#include "Xrd/XrdScheduler.hh"
33
34using namespace XrdSsi;
35
36/******************************************************************************/
37/* S t a t i c s & G l o b a l s */
38/******************************************************************************/
39
40namespace
41{
42XrdSsiMutex frMutex;
43}
44
45XrdSsiEvent::EventData *XrdSsiEvent::freeEvent = 0;
46
47namespace XrdSsi
48{
49extern XrdScheduler *schedP;
50}
51
52/******************************************************************************/
53/* A d d E v e n t */
54/******************************************************************************/
55
57{
58 EPNAME("AddEvent");
59 XrdSsiMutexMon monMutex(evMutex);
60
61// Indicate there is pending event here
62//
63 DEBUG("New event: isClear=" <<isClear <<" running=" <<running);
64 isClear = false;
65
66// If the base object has no status then we need to set it and schedule
67// ourselves for processing if not already running.
68//
69 if (!thisEvent.status)
70 {thisEvent.status = st;
71 thisEvent.response = resp;
72 if (!running)
73 {running = true;
75 }
76 return;
77 }
78
79// Allocate a new event object and chain it from the base event. This also
80// implies that we doesn't need to be scheduled as it already was scheduled.
81//
82 frMutex.Lock();
83 EventData *edP = freeEvent;
84 if (!edP) edP = new EventData(st, resp);
85 else {freeEvent = edP->next;
86 edP->status = st;
87 edP->response = resp;
88 edP->next = 0;
89 }
90 frMutex.UnLock();
91
92// Establish the last event
93//
94 if (lastEvent) lastEvent->next = edP;
95 else thisEvent .next = edP;
96 lastEvent = edP;
97}
98
99/******************************************************************************/
100/* C l r E v e n t */
101/******************************************************************************/
102
103void XrdSsiEvent::ClrEvent(XrdSsiEvent::EventData *fdP)
104{
105 EPNAME("ClrEvent");
106 EventData *xdP, *edP = fdP;
107
108// This method may be safely called on a undeleted EventData object even if
109// this event object has been deleted; as can happen in XeqEvent().
110// Clear any chained events. This loop ends with edP pointing to the last event.
111//
112 while(edP->next)
113 {edP = edP->next;
114 delete edP->status;
115 delete edP->response;
116 }
117
118// Place all chained elements, if any, in the free list
119//
120 if (fdP->next)
121 {frMutex.Lock();
122 xdP = fdP->next; edP->next = freeEvent; freeEvent = xdP;
123 frMutex.UnLock();
124 fdP->next = 0;
125 }
126
127// Clear the base event
128//
129 if (fdP->status) {delete fdP->status; fdP->status = 0;}
130 if (fdP->response) {delete fdP->response; fdP->response = 0;}
131
132// If we are clearing our events then indicate we are not running. Note that
133// this method is only called when cleaning up so we can't be running. We don't
134// trace clears on event copies as they always occur.
135//
136 if (fdP == &thisEvent)
137 {DEBUG("Self running=" <<running);
138 lastEvent = 0;
139 running = false;
140 isClear = true;
141 }
142}
143
144/******************************************************************************/
145/* D o I t */
146/******************************************************************************/
147
149{
150 EPNAME("RunEvent");
151 EventData *edP, myEvent;
152 int rc;
153
154// Process all of the events in our list. This is a tricky proposition because
155// the event executor may delete us upon return. Hence we do not directly use
156// any data members of this class, only copies. The return rc tells what to do.
157// rc > 0: terminate event processing and conclude in a normal fashion.
158// rc = 0: reflect next event.
159// rc < 0: immediately return as this object has become invalid.
160//
161 evMutex.Lock();
162do{thisEvent.Move2(myEvent);
163 lastEvent = 0;
164 isClear = true;
165 evMutex.UnLock();
166 edP = &myEvent;
167
168 do {if ((rc = XeqEvent(edP->status, &edP->response)) != 0) break;
169 edP = edP->next;
170 } while(edP);
171
172 ClrEvent(&myEvent);
173
174 if (rc)
175 {DEBUG("XeqEvent requested " <<(rc < 0 ? "halt" : "flush"));
176 if (rc < 0) return;
177 evMutex.Lock();
178 break;
179 }
180
181 evMutex.Lock();
182 } while(thisEvent.status);
183
184// Indicate we are no longer running
185//
186 running = false;
187 evMutex.UnLock();
188
189// The last thing we need to do is to tell the event handler that we are done
190// as it may decide to delete this object if no more events will occur.
191//
192 XeqEvFin();
193}
#define DEBUG(x)
#define EPNAME(x)
void Schedule(XrdJob *jp)
virtual void DoIt()
virtual void XeqEvFin()=0
void ClrEvent()
void AddEvent(XrdCl::XRootDStatus *st, XrdCl::AnyObject *resp)
virtual int XeqEvent(XrdCl::XRootDStatus *st, XrdCl::AnyObject **resp)=0
XrdScheduler * schedP