The Tor Browser / file comparison
comparison: js/jsd/jsd_lock.cpp
js/jsd/jsd_lock.cpp
- branch
- TOR_BUG_3246
- changeset 7
- 129ffea94266
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| -1:000000000000 | 0:6f7d19dd8f4e |
|---|---|
| 1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*- | |
| 2 * vim: set ts=8 sts=4 et sw=4 tw=99: | |
| 3 * This Source Code Form is subject to the terms of the Mozilla Public | |
| 4 * License, v. 2.0. If a copy of the MPL was not distributed with this | |
| 5 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ | |
| 6 | |
| 7 /* | |
| 8 * JavaScript Debugging support - Locking and threading support | |
| 9 */ | |
| 10 | |
| 11 /* | |
| 12 * ifdef JSD_USE_NSPR_LOCKS then you must build and run against NSPR2. | |
| 13 * Otherwise, there are stubs that can be filled in with your own locking | |
| 14 * code. Also, note that these stubs include a jsd_CurrentThread() | |
| 15 * implementation that only works on Win32 - this is needed for the inprocess | |
| 16 * Java-based debugger. | |
| 17 */ | |
| 18 | |
| 19 #include "jsd.h" | |
| 20 | |
| 21 #include "js/Utility.h" | |
| 22 | |
| 23 #ifdef JSD_THREADSAFE | |
| 24 | |
| 25 #ifdef JSD_USE_NSPR_LOCKS | |
| 26 | |
| 27 #include "prlock.h" | |
| 28 #include "prthread.h" | |
| 29 | |
| 30 #ifdef JSD_ATTACH_THREAD_HACK | |
| 31 #include "pprthred.h" /* need this as long as JS_AttachThread is needed */ | |
| 32 #endif | |
| 33 | |
| 34 struct JSDStaticLock | |
| 35 { | |
| 36 void* owner; | |
| 37 PRLock* lock; | |
| 38 int count; | |
| 39 #ifdef DEBUG | |
| 40 uint16_t sig; | |
| 41 #endif | |
| 42 }; | |
| 43 | |
| 44 /* | |
| 45 * This exists to wrap non-NSPR theads (e.g. Java threads) in NSPR wrappers. | |
| 46 * XXX We ignore the memory leak issue. | |
| 47 * It is claimed that future versions of NSPR will automatically wrap on | |
| 48 * the call to PR_GetCurrentThread. | |
| 49 * | |
| 50 * XXX We ignore the memory leak issue - i.e. we never call PR_DetachThread. | |
| 51 * | |
| 52 */ | |
| 53 #undef _CURRENT_THREAD | |
| 54 #ifdef JSD_ATTACH_THREAD_HACK | |
| 55 #define _CURRENT_THREAD(out) \ | |
| 56 JS_BEGIN_MACRO \ | |
| 57 out = (void*) PR_GetCurrentThread(); \ | |
| 58 if(!out) \ | |
| 59 out = (void*) JS_AttachThread(PR_USER_THREAD, PR_PRIORITY_NORMAL, \ | |
| 60 nullptr); \ | |
| 61 MOZ_ASSERT(out); \ | |
| 62 JS_END_MACRO | |
| 63 #else | |
| 64 #define _CURRENT_THREAD(out) \ | |
| 65 JS_BEGIN_MACRO \ | |
| 66 out = (void*) PR_GetCurrentThread(); \ | |
| 67 MOZ_ASSERT(out); \ | |
| 68 JS_END_MACRO | |
| 69 #endif | |
| 70 | |
| 71 #ifdef DEBUG | |
| 72 #define JSD_LOCK_SIG 0x10CC10CC | |
| 73 void ASSERT_VALID_LOCK(JSDStaticLock* lock) | |
| 74 { | |
| 75 MOZ_ASSERT(lock); | |
| 76 MOZ_ASSERT(lock->lock); | |
| 77 MOZ_ASSERT(lock->count >= 0); | |
| 78 MOZ_ASSERT(lock->sig == (uint16_t) JSD_LOCK_SIG); | |
| 79 } | |
| 80 #else | |
| 81 #define ASSERT_VALID_LOCK(x) ((void)0) | |
| 82 #endif | |
| 83 | |
| 84 JSDStaticLock* | |
| 85 jsd_CreateLock() | |
| 86 { | |
| 87 JSDStaticLock* lock; | |
| 88 | |
| 89 if( ! (lock = js_pod_calloc<JSDStaticLock>()) || | |
| 90 ! (lock->lock = PR_NewLock()) ) | |
| 91 { | |
| 92 if(lock) | |
| 93 { | |
| 94 free(lock); | |
| 95 lock = nullptr; | |
| 96 } | |
| 97 } | |
| 98 #ifdef DEBUG | |
| 99 if(lock) lock->sig = (uint16_t) JSD_LOCK_SIG; | |
| 100 #endif | |
| 101 return lock; | |
| 102 } | |
| 103 | |
| 104 void | |
| 105 jsd_Lock(JSDStaticLock* lock) | |
| 106 { | |
| 107 void* me; | |
| 108 ASSERT_VALID_LOCK(lock); | |
| 109 _CURRENT_THREAD(me); | |
| 110 | |
| 111 if(lock->owner == me) | |
| 112 { | |
| 113 lock->count++; | |
| 114 MOZ_ASSERT(lock->count > 1); | |
| 115 } | |
| 116 else | |
| 117 { | |
| 118 PR_Lock(lock->lock); /* this can block... */ | |
| 119 MOZ_ASSERT(lock->owner == 0); | |
| 120 MOZ_ASSERT(lock->count == 0); | |
| 121 lock->count = 1; | |
| 122 lock->owner = me; | |
| 123 } | |
| 124 } | |
| 125 | |
| 126 void | |
| 127 jsd_Unlock(JSDStaticLock* lock) | |
| 128 { | |
| 129 void* me; | |
| 130 ASSERT_VALID_LOCK(lock); | |
| 131 _CURRENT_THREAD(me); | |
| 132 | |
| 133 /* it's an error to unlock a lock you don't own */ | |
| 134 MOZ_ASSERT(lock->owner == me); | |
| 135 if(lock->owner != me) | |
| 136 return; | |
| 137 | |
| 138 if(--lock->count == 0) | |
| 139 { | |
| 140 lock->owner = nullptr; | |
| 141 PR_Unlock(lock->lock); | |
| 142 } | |
| 143 } | |
| 144 | |
| 145 #ifdef DEBUG | |
| 146 bool | |
| 147 jsd_IsLocked(JSDStaticLock* lock) | |
| 148 { | |
| 149 void* me; | |
| 150 ASSERT_VALID_LOCK(lock); | |
| 151 _CURRENT_THREAD(me); | |
| 152 if (lock->owner != me) | |
| 153 return false; | |
| 154 MOZ_ASSERT(lock->count > 0); | |
| 155 return true; | |
| 156 } | |
| 157 #endif /* DEBUG */ | |
| 158 | |
| 159 void* | |
| 160 jsd_CurrentThread() | |
| 161 { | |
| 162 void* me; | |
| 163 _CURRENT_THREAD(me); | |
| 164 return me; | |
| 165 } | |
| 166 | |
| 167 | |
| 168 #else /* ! JSD_USE_NSPR_LOCKS */ | |
| 169 | |
| 170 #ifdef WIN32 | |
| 171 #pragma message("!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!") | |
| 172 #pragma message("!! you are compiling the stubbed version of jsd_lock.c !!") | |
| 173 #pragma message("!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!") | |
| 174 #endif | |
| 175 | |
| 176 /* | |
| 177 * NOTE: 'Real' versions of these locks must be reentrant in the sense that | |
| 178 * they support nested calls to lock and unlock. | |
| 179 */ | |
| 180 | |
| 181 void* | |
| 182 jsd_CreateLock() | |
| 183 { | |
| 184 return (void*)1; | |
| 185 } | |
| 186 | |
| 187 void | |
| 188 jsd_Lock(void* lock) | |
| 189 { | |
| 190 } | |
| 191 | |
| 192 void | |
| 193 jsd_Unlock(void* lock) | |
| 194 { | |
| 195 } | |
| 196 | |
| 197 #ifdef DEBUG | |
| 198 bool | |
| 199 jsd_IsLocked(void* lock) | |
| 200 { | |
| 201 return true; | |
| 202 } | |
| 203 #endif /* DEBUG */ | |
| 204 | |
| 205 /* | |
| 206 * This Windows only thread id code is here to allow the Java-based | |
| 207 * JSDebugger to work with the single threaded js.c shell (even without | |
| 208 * real locking and threading support). | |
| 209 */ | |
| 210 | |
| 211 #ifdef WIN32 | |
| 212 /* bogus (but good enough) declaration*/ | |
| 213 extern void* __stdcall GetCurrentThreadId(void); | |
| 214 #endif | |
| 215 | |
| 216 void* | |
| 217 jsd_CurrentThread() | |
| 218 { | |
| 219 #ifdef WIN32 | |
| 220 return GetCurrentThreadId(); | |
| 221 #else | |
| 222 return (void*)1; | |
| 223 #endif | |
| 224 } | |
| 225 | |
| 226 #endif /* JSD_USE_NSPR_LOCKS */ | |
| 227 | |
| 228 #endif /* JSD_THREADSAFE */ |
