#include "config.h"
#include "JSLock.h"
#include "Heap.h"
#include "CallFrame.h"
#include "JSGlobalObject.h"
#include "JSObject.h"
#include "Operations.h"
#if USE(PTHREADS)
#include <pthread.h>
#endif
namespace JSC {
Mutex* GlobalJSLock::s_sharedInstanceLock = 0;
GlobalJSLock::GlobalJSLock()
{
s_sharedInstanceLock->lock();
}
GlobalJSLock::~GlobalJSLock()
{
s_sharedInstanceLock->unlock();
}
void GlobalJSLock::initialize()
{
s_sharedInstanceLock = new Mutex();
}
JSLockHolder::JSLockHolder(ExecState* exec)
: m_vm(&exec->vm())
{
init();
}
JSLockHolder::JSLockHolder(VM* vm)
: m_vm(vm)
{
init();
}
JSLockHolder::JSLockHolder(VM& vm)
: m_vm(&vm)
{
init();
}
void JSLockHolder::init()
{
m_vm->apiLock().lock();
}
JSLockHolder::~JSLockHolder()
{
RefPtr<JSLock> apiLock(&m_vm->apiLock());
m_vm.clear();
apiLock->unlock();
}
JSLock::JSLock(VM* vm)
: m_ownerThread(0)
, m_lockCount(0)
, m_lockDropDepth(0)
, m_vm(vm)
{
m_spinLock.Init();
}
JSLock::~JSLock()
{
}
void JSLock::willDestroyVM(VM* vm)
{
ASSERT_UNUSED(vm, m_vm == vm);
m_vm = 0;
}
void JSLock::lock()
{
ThreadIdentifier currentThread = WTF::currentThread();
{
SpinLockHolder holder(&m_spinLock);
if (m_ownerThread == currentThread && m_lockCount) {
m_lockCount++;
return;
}
}
m_lock.lock();
{
SpinLockHolder holder(&m_spinLock);
m_ownerThread = currentThread;
ASSERT(!m_lockCount);
m_lockCount = 1;
}
}
void JSLock::unlock()
{
SpinLockHolder holder(&m_spinLock);
ASSERT(currentThreadIsHoldingLock());
m_lockCount--;
if (!m_lockCount)
m_lock.unlock();
}
void JSLock::lock(ExecState* exec)
{
exec->vm().apiLock().lock();
}
void JSLock::unlock(ExecState* exec)
{
exec->vm().apiLock().unlock();
}
bool JSLock::currentThreadIsHoldingLock()
{
return m_lockCount && m_ownerThread == WTF::currentThread();
}
unsigned JSLock::dropAllLocks(SpinLock& spinLock)
{
#if PLATFORM(IOS)
ASSERT_UNUSED(spinLock, spinLock.IsHeld());
unsigned lockCount = m_lockCount;
if (!lockCount || m_ownerThread != WTF::currentThread())
return 0;
if (m_lockDropDepth)
return 0;
m_lockDropDepth++;
m_lockCount = 0;
m_lock.unlock();
return lockCount;
#else
UNUSED_PARAM(spinLock);
if (m_lockDropDepth++)
return 0;
return dropAllLocksUnconditionally(spinLock);
#endif
}
unsigned JSLock::dropAllLocksUnconditionally(SpinLock& spinLock)
{
#if PLATFORM(IOS)
ASSERT_UNUSED(spinLock, spinLock.IsHeld());
unsigned lockCount;
lockCount = m_lockCount;
if (!lockCount || m_ownerThread != WTF::currentThread())
return 0;
m_lockDropDepth++;
m_lockCount = 0;
m_lock.unlock();
return lockCount;
#else
UNUSED_PARAM(spinLock);
unsigned lockCount = m_lockCount;
for (unsigned i = 0; i < lockCount; i++)
unlock();
return lockCount;
#endif
}
void JSLock::grabAllLocks(unsigned lockCount, SpinLock& spinLock)
{
#if PLATFORM(IOS)
ASSERT(spinLock.IsHeld());
if (!lockCount)
return;
ThreadIdentifier currentThread = WTF::currentThread();
if (m_ownerThread == currentThread && m_lockCount) {
m_lockCount += lockCount;
m_lockDropDepth--;
return;
}
spinLock.Unlock();
m_lock.lock();
spinLock.Lock();
m_ownerThread = currentThread;
ASSERT(!m_lockCount);
m_lockCount = lockCount;
m_lockDropDepth--;
#else
UNUSED_PARAM(spinLock);
for (unsigned i = 0; i < lockCount; i++)
lock();
m_lockDropDepth--;
#endif
}
#if PLATFORM(IOS)
JSLock::DropAllLocks::DropAllLocks(ExecState* exec, AlwaysDropLocksTag alwaysDropLocks)
: m_lockCount(0)
, m_vm(&exec->vm())
{
SpinLock& spinLock = m_vm->apiLock().m_spinLock;
SpinLockHolder holder(&spinLock);
if (alwaysDropLocks)
m_lockCount = m_vm->apiLock().dropAllLocksUnconditionally(spinLock);
else
m_lockCount = m_vm->apiLock().dropAllLocks(spinLock);
}
JSLock::DropAllLocks::DropAllLocks(VM* vm, AlwaysDropLocksTag alwaysDropLocks)
: m_lockCount(0)
, m_vm(vm)
{
SpinLock& spinLock = m_vm->apiLock().m_spinLock;
SpinLockHolder holder(&spinLock);
if (alwaysDropLocks)
m_lockCount = m_vm->apiLock().dropAllLocksUnconditionally(spinLock);
else
m_lockCount = m_vm->apiLock().dropAllLocks(spinLock);
}
JSLock::DropAllLocks::~DropAllLocks()
{
SpinLock& spinLock = m_vm->apiLock().m_spinLock;
SpinLockHolder holder(&spinLock);
m_vm->apiLock().grabAllLocks(m_lockCount, spinLock);
}
#else
JSLock::DropAllLocks::DropAllLocks(ExecState* exec)
: m_lockCount(0)
, m_vm(&exec->vm())
{
SpinLock& spinLock = m_vm->apiLock().m_spinLock;
m_lockCount = m_vm->apiLock().dropAllLocks(spinLock);
}
JSLock::DropAllLocks::DropAllLocks(VM* vm)
: m_lockCount(0)
, m_vm(vm)
{
SpinLock& spinLock = m_vm->apiLock().m_spinLock;
m_lockCount = m_vm->apiLock().dropAllLocks(spinLock);
}
JSLock::DropAllLocks::~DropAllLocks()
{
SpinLock& spinLock = m_vm->apiLock().m_spinLock;
m_vm->apiLock().grabAllLocks(m_lockCount, spinLock);
}
#endif
}