XRootD
XrdXrootdFileLock1.cc
Go to the documentation of this file.
1 /******************************************************************************/
2 /* */
3 /* X r d X r o o t d F i l e L o c k 1 . c c */
4 /* */
5 /* (c) 2004 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 <cstdlib>
31 
32 #include "XrdOuc/XrdOucHash.hh"
33 
35 
36 /******************************************************************************/
37 /* L o c a l C l a s s e s */
38 /******************************************************************************/
39 
41 {
42 public:
43 
46 
48  {if (mode == 'r') {numReaders = 1; numWriters = 0;}
49  else {numReaders = 0; numWriters = 1;}
50  }
52 };
53 
55 {
56 public:
57 
59  {mp = mutex; mp->Lock();}
61  {mp->UnLock();}
62 private:
63 XrdSysMutex *mp;
64 };
65 
66 /******************************************************************************/
67 /* G l o b a l s */
68 /******************************************************************************/
69 
71 
72 XrdSysMutex XrdXrootdFileLock1::LTMutex;
73 
74 const char *XrdXrootdFileLock1::TraceID = "FileLock1";
75 
76 /******************************************************************************/
77 /* L o c k */
78 /******************************************************************************/
79 
80 int XrdXrootdFileLock1::Lock(const char *path, char mode, bool force)
81 {
82  XrdXrootdLockFileLock locker(&LTMutex);
84 
85 // See if we already have a lock on this file
86 //
87  if ((lp = XrdXrootdLockTable.Find(path)))
88  {if (mode == 'r')
89  {if (lp->numWriters && !force)
90  return -lp->numWriters;
91  lp->numReaders++;
92  } else {
93  if ((lp->numReaders || lp->numWriters) && !force)
94  return (lp->numWriters ? -lp->numWriters : lp->numReaders);
95  lp->numWriters++;
96  }
97  return 0;
98  }
99 
100 // Item does not exist, add it to the table
101 //
102  XrdXrootdLockTable.Add(path, new XrdXrootdFileLockInfo(mode));
103  return 0;
104 }
105 
106 /******************************************************************************/
107 /* */
108 /* n u m L o c k s */
109 /* */
110 /******************************************************************************/
111 
112 void XrdXrootdFileLock1::numLocks(const char *path, int &rcnt, int &wcnt)
113 {
114  XrdXrootdLockFileLock locker(&LTMutex);
116 
117  if (!(lp = XrdXrootdLockTable.Find(path))) rcnt = wcnt = 0;
118  else {rcnt = lp->numReaders; wcnt = lp->numWriters;}
119 }
120 
121 /******************************************************************************/
122 /* U n l o c k */
123 /******************************************************************************/
124 
125 int XrdXrootdFileLock1::Unlock(const char *path, char mode)
126 {
127  XrdXrootdLockFileLock locker(&LTMutex);
129 
130 // See if we already have a lock on this file
131 //
132  if (!(lp = XrdXrootdLockTable.Find(path))) return 1;
133 
134 // Adjust the lock information
135 //
136  if (mode == 'r')
137  {if (lp->numReaders == 0) return 1;
138  lp->numReaders--;
139  } else {
140  if (lp->numWriters == 0) return 1;
141  lp->numWriters--;
142  }
143 
144 // Delete the entry if we no longer need it
145 //
146  if (lp->numReaders == 0 && lp->numWriters == 0)
147  XrdXrootdLockTable.Del(path);
148  return 0;
149 }
XrdOucHash< XrdXrootdFileLockInfo > XrdXrootdLockTable
void numLocks(const char *path, int &rcnt, int &wcnt)
int Unlock(const char *path, char mode)
int Lock(const char *path, char mode, bool force)
XrdXrootdLockFileLock(XrdSysMutex *mutex)