1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/js/jsd/jsd_lock.cpp Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,228 @@
1.4 +/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
1.5 + * vim: set ts=8 sts=4 et sw=4 tw=99:
1.6 + * This Source Code Form is subject to the terms of the Mozilla Public
1.7 + * License, v. 2.0. If a copy of the MPL was not distributed with this
1.8 + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
1.9 +
1.10 +/*
1.11 + * JavaScript Debugging support - Locking and threading support
1.12 + */
1.13 +
1.14 +/*
1.15 +* ifdef JSD_USE_NSPR_LOCKS then you must build and run against NSPR2.
1.16 +* Otherwise, there are stubs that can be filled in with your own locking
1.17 +* code. Also, note that these stubs include a jsd_CurrentThread()
1.18 +* implementation that only works on Win32 - this is needed for the inprocess
1.19 +* Java-based debugger.
1.20 +*/
1.21 +
1.22 +#include "jsd.h"
1.23 +
1.24 +#include "js/Utility.h"
1.25 +
1.26 +#ifdef JSD_THREADSAFE
1.27 +
1.28 +#ifdef JSD_USE_NSPR_LOCKS
1.29 +
1.30 +#include "prlock.h"
1.31 +#include "prthread.h"
1.32 +
1.33 +#ifdef JSD_ATTACH_THREAD_HACK
1.34 +#include "pprthred.h" /* need this as long as JS_AttachThread is needed */
1.35 +#endif
1.36 +
1.37 +struct JSDStaticLock
1.38 +{
1.39 + void* owner;
1.40 + PRLock* lock;
1.41 + int count;
1.42 +#ifdef DEBUG
1.43 + uint16_t sig;
1.44 +#endif
1.45 +};
1.46 +
1.47 +/*
1.48 + * This exists to wrap non-NSPR theads (e.g. Java threads) in NSPR wrappers.
1.49 + * XXX We ignore the memory leak issue.
1.50 + * It is claimed that future versions of NSPR will automatically wrap on
1.51 + * the call to PR_GetCurrentThread.
1.52 + *
1.53 + * XXX We ignore the memory leak issue - i.e. we never call PR_DetachThread.
1.54 + *
1.55 + */
1.56 +#undef _CURRENT_THREAD
1.57 +#ifdef JSD_ATTACH_THREAD_HACK
1.58 +#define _CURRENT_THREAD(out) \
1.59 +JS_BEGIN_MACRO \
1.60 + out = (void*) PR_GetCurrentThread(); \
1.61 + if(!out) \
1.62 + out = (void*) JS_AttachThread(PR_USER_THREAD, PR_PRIORITY_NORMAL, \
1.63 + nullptr); \
1.64 + MOZ_ASSERT(out); \
1.65 +JS_END_MACRO
1.66 +#else
1.67 +#define _CURRENT_THREAD(out) \
1.68 +JS_BEGIN_MACRO \
1.69 + out = (void*) PR_GetCurrentThread(); \
1.70 + MOZ_ASSERT(out); \
1.71 +JS_END_MACRO
1.72 +#endif
1.73 +
1.74 +#ifdef DEBUG
1.75 +#define JSD_LOCK_SIG 0x10CC10CC
1.76 +void ASSERT_VALID_LOCK(JSDStaticLock* lock)
1.77 +{
1.78 + MOZ_ASSERT(lock);
1.79 + MOZ_ASSERT(lock->lock);
1.80 + MOZ_ASSERT(lock->count >= 0);
1.81 + MOZ_ASSERT(lock->sig == (uint16_t) JSD_LOCK_SIG);
1.82 +}
1.83 +#else
1.84 +#define ASSERT_VALID_LOCK(x) ((void)0)
1.85 +#endif
1.86 +
1.87 +JSDStaticLock*
1.88 +jsd_CreateLock()
1.89 +{
1.90 + JSDStaticLock* lock;
1.91 +
1.92 + if( ! (lock = js_pod_calloc<JSDStaticLock>()) ||
1.93 + ! (lock->lock = PR_NewLock()) )
1.94 + {
1.95 + if(lock)
1.96 + {
1.97 + free(lock);
1.98 + lock = nullptr;
1.99 + }
1.100 + }
1.101 +#ifdef DEBUG
1.102 + if(lock) lock->sig = (uint16_t) JSD_LOCK_SIG;
1.103 +#endif
1.104 + return lock;
1.105 +}
1.106 +
1.107 +void
1.108 +jsd_Lock(JSDStaticLock* lock)
1.109 +{
1.110 + void* me;
1.111 + ASSERT_VALID_LOCK(lock);
1.112 + _CURRENT_THREAD(me);
1.113 +
1.114 + if(lock->owner == me)
1.115 + {
1.116 + lock->count++;
1.117 + MOZ_ASSERT(lock->count > 1);
1.118 + }
1.119 + else
1.120 + {
1.121 + PR_Lock(lock->lock); /* this can block... */
1.122 + MOZ_ASSERT(lock->owner == 0);
1.123 + MOZ_ASSERT(lock->count == 0);
1.124 + lock->count = 1;
1.125 + lock->owner = me;
1.126 + }
1.127 +}
1.128 +
1.129 +void
1.130 +jsd_Unlock(JSDStaticLock* lock)
1.131 +{
1.132 + void* me;
1.133 + ASSERT_VALID_LOCK(lock);
1.134 + _CURRENT_THREAD(me);
1.135 +
1.136 + /* it's an error to unlock a lock you don't own */
1.137 + MOZ_ASSERT(lock->owner == me);
1.138 + if(lock->owner != me)
1.139 + return;
1.140 +
1.141 + if(--lock->count == 0)
1.142 + {
1.143 + lock->owner = nullptr;
1.144 + PR_Unlock(lock->lock);
1.145 + }
1.146 +}
1.147 +
1.148 +#ifdef DEBUG
1.149 +bool
1.150 +jsd_IsLocked(JSDStaticLock* lock)
1.151 +{
1.152 + void* me;
1.153 + ASSERT_VALID_LOCK(lock);
1.154 + _CURRENT_THREAD(me);
1.155 + if (lock->owner != me)
1.156 + return false;
1.157 + MOZ_ASSERT(lock->count > 0);
1.158 + return true;
1.159 +}
1.160 +#endif /* DEBUG */
1.161 +
1.162 +void*
1.163 +jsd_CurrentThread()
1.164 +{
1.165 + void* me;
1.166 + _CURRENT_THREAD(me);
1.167 + return me;
1.168 +}
1.169 +
1.170 +
1.171 +#else /* ! JSD_USE_NSPR_LOCKS */
1.172 +
1.173 +#ifdef WIN32
1.174 +#pragma message("!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!")
1.175 +#pragma message("!! you are compiling the stubbed version of jsd_lock.c !!")
1.176 +#pragma message("!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!")
1.177 +#endif
1.178 +
1.179 +/*
1.180 + * NOTE: 'Real' versions of these locks must be reentrant in the sense that
1.181 + * they support nested calls to lock and unlock.
1.182 + */
1.183 +
1.184 +void*
1.185 +jsd_CreateLock()
1.186 +{
1.187 + return (void*)1;
1.188 +}
1.189 +
1.190 +void
1.191 +jsd_Lock(void* lock)
1.192 +{
1.193 +}
1.194 +
1.195 +void
1.196 +jsd_Unlock(void* lock)
1.197 +{
1.198 +}
1.199 +
1.200 +#ifdef DEBUG
1.201 +bool
1.202 +jsd_IsLocked(void* lock)
1.203 +{
1.204 + return true;
1.205 +}
1.206 +#endif /* DEBUG */
1.207 +
1.208 +/*
1.209 + * This Windows only thread id code is here to allow the Java-based
1.210 + * JSDebugger to work with the single threaded js.c shell (even without
1.211 + * real locking and threading support).
1.212 + */
1.213 +
1.214 +#ifdef WIN32
1.215 +/* bogus (but good enough) declaration*/
1.216 +extern void* __stdcall GetCurrentThreadId(void);
1.217 +#endif
1.218 +
1.219 +void*
1.220 +jsd_CurrentThread()
1.221 +{
1.222 +#ifdef WIN32
1.223 + return GetCurrentThreadId();
1.224 +#else
1.225 + return (void*)1;
1.226 +#endif
1.227 +}
1.228 +
1.229 +#endif /* JSD_USE_NSPR_LOCKS */
1.230 +
1.231 +#endif /* JSD_THREADSAFE */
