Retro68/gcc/libphobos/libdruntime/rt/critical_.d
Wolfgang Thaller 6fbf4226da gcc-9.1
2019-06-20 20:10:10 +02:00

69 lines
1.5 KiB
D

/**
* Implementation of support routines for synchronized blocks.
*
* Copyright: Copyright Digital Mars 2000 - 2011.
* License: $(WEB www.boost.org/LICENSE_1_0.txt, Boost License 1.0).
* Authors: Walter Bright, Sean Kelly
*/
/* Copyright Digital Mars 2000 - 2011.
* Distributed under the Boost Software License, Version 1.0.
* (See accompanying file LICENSE or copy at
* http://www.boost.org/LICENSE_1_0.txt)
*/
module rt.critical_;
nothrow:
import rt.monitor_, core.atomic;
extern (C) void _d_critical_init()
{
initMutex(cast(Mutex*)&gcs.mtx);
head = &gcs;
}
extern (C) void _d_critical_term()
{
for (auto p = head; p; p = p.next)
destroyMutex(cast(Mutex*)&p.mtx);
}
extern (C) void _d_criticalenter(D_CRITICAL_SECTION* cs)
{
ensureMutex(cast(shared(D_CRITICAL_SECTION*)) cs);
lockMutex(&cs.mtx);
}
extern (C) void _d_criticalexit(D_CRITICAL_SECTION* cs)
{
unlockMutex(&cs.mtx);
}
private:
shared D_CRITICAL_SECTION* head;
shared D_CRITICAL_SECTION gcs;
struct D_CRITICAL_SECTION
{
D_CRITICAL_SECTION* next;
Mutex mtx;
}
void ensureMutex(shared(D_CRITICAL_SECTION)* cs)
{
if (atomicLoad!(MemoryOrder.acq)(cs.next) is null)
{
lockMutex(cast(Mutex*)&gcs.mtx);
if (atomicLoad!(MemoryOrder.raw)(cs.next) is null)
{
initMutex(cast(Mutex*)&cs.mtx);
auto ohead = head;
head = cs;
atomicStore!(MemoryOrder.rel)(cs.next, ohead);
}
unlockMutex(cast(Mutex*)&gcs.mtx);
}
}