1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/xpcom/glue/Mutex.h Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,235 @@
1.4 +/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
1.5 + * vim: sw=4 ts=4 et :
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 +#ifndef mozilla_Mutex_h
1.11 +#define mozilla_Mutex_h
1.12 +
1.13 +#include "prlock.h"
1.14 +
1.15 +#include "mozilla/BlockingResourceBase.h"
1.16 +#include "mozilla/GuardObjects.h"
1.17 +
1.18 +//
1.19 +// Provides:
1.20 +//
1.21 +// - Mutex, a non-recursive mutex
1.22 +// - MutexAutoLock, an RAII class for ensuring that Mutexes are properly
1.23 +// locked and unlocked
1.24 +// - MutexAutoUnlock, complementary sibling to MutexAutoLock
1.25 +//
1.26 +// - OffTheBooksMutex, a non-recursive mutex that doesn't do leak checking
1.27 +// - OffTheBooksMutexAuto{Lock,Unlock} - Like MutexAuto{Lock,Unlock}, but for
1.28 +// an OffTheBooksMutex.
1.29 +//
1.30 +// Using MutexAutoLock/MutexAutoUnlock etc. is MUCH preferred to making bare
1.31 +// calls to Lock and Unlock.
1.32 +//
1.33 +namespace mozilla {
1.34 +
1.35 +/**
1.36 + * OffTheBooksMutex is identical to Mutex, except that OffTheBooksMutex doesn't
1.37 + * include leak checking. Sometimes you want to intentionally "leak" a mutex
1.38 + * until shutdown; in these cases, OffTheBooksMutex is for you.
1.39 + */
1.40 +class NS_COM_GLUE OffTheBooksMutex : BlockingResourceBase
1.41 +{
1.42 +public:
1.43 + /**
1.44 + * @param name A name which can reference this lock
1.45 + * @returns If failure, nullptr
1.46 + * If success, a valid Mutex* which must be destroyed
1.47 + * by Mutex::DestroyMutex()
1.48 + **/
1.49 + OffTheBooksMutex(const char* name) :
1.50 + BlockingResourceBase(name, eMutex)
1.51 + {
1.52 + mLock = PR_NewLock();
1.53 + if (!mLock)
1.54 + NS_RUNTIMEABORT("Can't allocate mozilla::Mutex");
1.55 + }
1.56 +
1.57 + ~OffTheBooksMutex()
1.58 + {
1.59 + NS_ASSERTION(mLock,
1.60 + "improperly constructed Lock or double free");
1.61 + // NSPR does consistency checks for us
1.62 + PR_DestroyLock(mLock);
1.63 + mLock = 0;
1.64 + }
1.65 +
1.66 +#ifndef DEBUG
1.67 + /**
1.68 + * Lock
1.69 + * @see prlock.h
1.70 + **/
1.71 + void Lock()
1.72 + {
1.73 + PR_Lock(mLock);
1.74 + }
1.75 +
1.76 + /**
1.77 + * Unlock
1.78 + * @see prlock.h
1.79 + **/
1.80 + void Unlock()
1.81 + {
1.82 + PR_Unlock(mLock);
1.83 + }
1.84 +
1.85 + /**
1.86 + * AssertCurrentThreadOwns
1.87 + * @see prlock.h
1.88 + **/
1.89 + void AssertCurrentThreadOwns () const
1.90 + {
1.91 + }
1.92 +
1.93 + /**
1.94 + * AssertNotCurrentThreadOwns
1.95 + * @see prlock.h
1.96 + **/
1.97 + void AssertNotCurrentThreadOwns () const
1.98 + {
1.99 + }
1.100 +
1.101 +#else
1.102 + void Lock();
1.103 + void Unlock();
1.104 +
1.105 + void AssertCurrentThreadOwns () const
1.106 + {
1.107 + PR_ASSERT_CURRENT_THREAD_OWNS_LOCK(mLock);
1.108 + }
1.109 +
1.110 + void AssertNotCurrentThreadOwns () const
1.111 + {
1.112 + // FIXME bug 476536
1.113 + }
1.114 +
1.115 +#endif // ifndef DEBUG
1.116 +
1.117 +private:
1.118 + OffTheBooksMutex();
1.119 + OffTheBooksMutex(const OffTheBooksMutex&);
1.120 + OffTheBooksMutex& operator=(const OffTheBooksMutex&);
1.121 +
1.122 + PRLock* mLock;
1.123 +
1.124 + friend class CondVar;
1.125 +};
1.126 +
1.127 +/**
1.128 + * Mutex
1.129 + * When possible, use MutexAutoLock/MutexAutoUnlock to lock/unlock this
1.130 + * mutex within a scope, instead of calling Lock/Unlock directly.
1.131 + */
1.132 +class NS_COM_GLUE Mutex : public OffTheBooksMutex
1.133 +{
1.134 +public:
1.135 + Mutex(const char* name)
1.136 + : OffTheBooksMutex(name)
1.137 + {
1.138 + MOZ_COUNT_CTOR(Mutex);
1.139 + }
1.140 +
1.141 + ~Mutex()
1.142 + {
1.143 + MOZ_COUNT_DTOR(Mutex);
1.144 + }
1.145 +
1.146 +private:
1.147 + Mutex();
1.148 + Mutex(const Mutex&);
1.149 + Mutex& operator=(const Mutex&);
1.150 +};
1.151 +
1.152 +/**
1.153 + * MutexAutoLock
1.154 + * Acquires the Mutex when it enters scope, and releases it when it leaves
1.155 + * scope.
1.156 + *
1.157 + * MUCH PREFERRED to bare calls to Mutex.Lock and Unlock.
1.158 + */
1.159 +template<typename T>
1.160 +class NS_COM_GLUE MOZ_STACK_CLASS BaseAutoLock
1.161 +{
1.162 +public:
1.163 + /**
1.164 + * Constructor
1.165 + * The constructor aquires the given lock. The destructor
1.166 + * releases the lock.
1.167 + *
1.168 + * @param aLock A valid mozilla::Mutex* returned by
1.169 + * mozilla::Mutex::NewMutex.
1.170 + **/
1.171 + BaseAutoLock(T& aLock MOZ_GUARD_OBJECT_NOTIFIER_PARAM) :
1.172 + mLock(&aLock)
1.173 + {
1.174 + MOZ_GUARD_OBJECT_NOTIFIER_INIT;
1.175 + NS_ASSERTION(mLock, "null mutex");
1.176 + mLock->Lock();
1.177 + }
1.178 +
1.179 + ~BaseAutoLock(void) {
1.180 + mLock->Unlock();
1.181 + }
1.182 +
1.183 +private:
1.184 + BaseAutoLock();
1.185 + BaseAutoLock(BaseAutoLock&);
1.186 + BaseAutoLock& operator=(BaseAutoLock&);
1.187 + static void* operator new(size_t) CPP_THROW_NEW;
1.188 + static void operator delete(void*);
1.189 +
1.190 + T* mLock;
1.191 + MOZ_DECL_USE_GUARD_OBJECT_NOTIFIER
1.192 +};
1.193 +
1.194 +typedef BaseAutoLock<Mutex> MutexAutoLock;
1.195 +typedef BaseAutoLock<OffTheBooksMutex> OffTheBooksMutexAutoLock;
1.196 +
1.197 +/**
1.198 + * MutexAutoUnlock
1.199 + * Releases the Mutex when it enters scope, and re-acquires it when it leaves
1.200 + * scope.
1.201 + *
1.202 + * MUCH PREFERRED to bare calls to Mutex.Unlock and Lock.
1.203 + */
1.204 +template<typename T>
1.205 +class NS_COM_GLUE MOZ_STACK_CLASS BaseAutoUnlock
1.206 +{
1.207 +public:
1.208 + BaseAutoUnlock(T& aLock MOZ_GUARD_OBJECT_NOTIFIER_PARAM) :
1.209 + mLock(&aLock)
1.210 + {
1.211 + MOZ_GUARD_OBJECT_NOTIFIER_INIT;
1.212 + NS_ASSERTION(mLock, "null lock");
1.213 + mLock->Unlock();
1.214 + }
1.215 +
1.216 + ~BaseAutoUnlock()
1.217 + {
1.218 + mLock->Lock();
1.219 + }
1.220 +
1.221 +private:
1.222 + BaseAutoUnlock();
1.223 + BaseAutoUnlock(BaseAutoUnlock&);
1.224 + BaseAutoUnlock& operator =(BaseAutoUnlock&);
1.225 + static void* operator new(size_t) CPP_THROW_NEW;
1.226 + static void operator delete(void*);
1.227 +
1.228 + T* mLock;
1.229 + MOZ_DECL_USE_GUARD_OBJECT_NOTIFIER
1.230 +};
1.231 +
1.232 +typedef BaseAutoUnlock<Mutex> MutexAutoUnlock;
1.233 +typedef BaseAutoUnlock<OffTheBooksMutex> OffTheBooksMutexAutoUnlock;
1.234 +
1.235 +} // namespace mozilla
1.236 +
1.237 +
1.238 +#endif // ifndef mozilla_Mutex_h
