1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
/* lock.h: RECURSIVE LOCKS
 *
 * $Id: //info.ravenbrook.com/project/mps/custom/cet/main/code/lock.h#6 $
 * Copyright (c) 2001-2014 Ravenbrook Limited.  See end of file for license.
 */

#ifndef lock_h
#define lock_h

#include "mpm.h"


#define LockSig         ((Sig)0x51970CC9) /* SIGnature LOCK */


/* LockSize -- Return the size of a LockStruct
 *
 * Supports allocation of locks.
 */

extern size_t LockSize(void);


/* LockInitGlobal -- initialize global locks */

extern void LockInitGlobal(void);


/*  LockInit/Finish
 *
 *  lock points to the allocated lock structure.  A lock has no
 *  owner after initialisation.
 */

extern void LockInit(Lock lock);
extern void LockFinish(Lock lock);


/*  LockClaimRecursive
 *
 *  This is called to increase the number of claims on the lock.
 *  LockClaimRecursive will wait until the lock is not owned by another
 *  thread and return with the lock owned.
 *  This can be called recursively.
 */

extern void LockClaimRecursive(Lock lock);


/*  LockReleaseRecursive
 *
 *  This is called to reduce the number of claims on the lock.
 *  If the number of claims drops to zero, ownership is relinquished.
 *  This must not be called without possession of the lock.
 */

extern void LockReleaseRecursive(Lock lock);


/*  LockClaim
 *
 *  This may only be used when the lock is not already owned by
 *  the calling thread.
 *  When used it behaves like LockClaimRecursive, but must be
 *  matched by a call to LockRelease.
 */

extern void LockClaim(Lock lock);


/*  LockRelease
 *
 *  This must only be used to release a Lock symmetrically
 *  with LockClaim.  It therefore should only be called with
 *  a single claim.
 */

extern void LockRelease(Lock lock);


/*  LockCheck -- Validation */

extern Bool LockCheck(Lock lock);


/* LockIsHeld -- test whether lock is held by any thread */

extern Bool LockIsHeld(Lock lock);


/*  == Global locks == */


/*  LockClaimGlobalRecursive
 *
 *  This is called to increase the number of claims on the recursive
 *  global lock.  LockClaimRecursive will wait until the lock is not
 *  owned by another thread and return with the lock owned.
 *  This can be called recursively.
 */

extern void LockClaimGlobalRecursive(void);


/*  LockReleaseGlobalRecursive
 *
 *  This is called to reduce the number of claims on the recursive
 *  global lock. If the number of claims drops to zero, ownership
 *  is relinquished. This must not be called without possession of
 *  the lock.
 */

extern void LockReleaseGlobalRecursive(void);


/*  LockClaimGlobal
 *
 *  This is called to claim the binary global lock, and may only be
 *  used if that lock is not already owned by the calling thread.
 *  It must be matched by a call to LockReleaseGlobal.
 */

extern void LockClaimGlobal(void);


/*  LockReleaseGlobal
 *
 *  This must only be used to release the binary global lock
 *  symmetrically with LockClaimGlobal.
 *  It therefore should only be called with a single claim.
 */

extern void LockReleaseGlobal(void);


/* LockSetup -- one-time lock initialization */

extern void LockSetup(void);


#endif /* lock_h */


/* C. COPYRIGHT AND LICENSE
 *
 * Copyright (C) 2001-2014 Ravenbrook Limited <http://www.ravenbrook.com/>.
 * All rights reserved.  This is an open source license.  Contact
 * Ravenbrook for commercial licensing options.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 * 
 * 1. Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 * 
 * 2. Redistributions in binary form must reproduce the above copyright
 * notice, this list of conditions and the following disclaimer in the
 * documentation and/or other materials provided with the distribution.
 * 
 * 3. Redistributions in any form must be accompanied by information on how
 * to obtain complete source code for this software and any accompanying
 * software that uses this software.  The source code must either be
 * included in the distribution or be available for no more than the cost
 * of distribution plus a nominal fee, and must be freely redistributable
 * under reasonable conditions.  For an executable file, complete source
 * code means the source code for all modules it contains. It does not
 * include source code for modules or files that typically accompany the
 * major components of the operating system on which the executable file
 * runs.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
 * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
 * PURPOSE, OR NON-INFRINGEMENT, ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT HOLDERS AND CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
 * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */