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Use one semaphore for the process's lifetime, for efficiency.

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Use a name that works on Linux.
Try several random names to avoid conflicts with other processes.

This was SVN commit r5315.
This commit is contained in:
Ykkrosh 2007-09-02 21:16:23 +00:00
parent a22e73406a
commit 027c3c7cc0
2 changed files with 51 additions and 23 deletions
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68
source/tools/atlas/GameInterface/MessagePasserImpl.cpp
View File

@ -4,13 +4,54 @@
#include "Messages.h"
#include "lib/timer.h"
#include "lib/rand.h"
using namespace AtlasMessage;
MessagePasserImpl::MessagePasserImpl()
: m_Trace(false)
: m_Trace(false), m_Semaphore(NULL)
{
int tries = 0;
while (tries++ < 16) // some arbitrary cut-off point to avoid infinite loops
{
CStr name = "/wfg-atlas-msgpass-" + CStr(rand(100000, 1000000));
sem_t* sem = sem_open(name, O_CREAT | O_EXCL, 0700, 0);
if (sem == SEM_FAILED)
{
int err = errno;
if (err == EEXIST)
{
// Semaphore already exists - try another one
continue;
}
// Otherwise, it's a probably-fatal error
debug_printf("errno: %d (%s)\n", err, strerror(err));
debug_warn("sem_open failed");
break;
}
// Succeeded - use this semaphore
m_Semaphore = sem;
m_SemaphoreName = name;
break;
}
if (! m_Semaphore)
{
debug_warn("Failed to create semaphore for Atlas - giving up");
// We will probably crash later - maybe we could fall back on sem_init, if this
// ever fails in practice
}
}
MessagePasserImpl::~MessagePasserImpl()
{
if (m_Semaphore)
{
// Clean up
sem_close(m_Semaphore);
sem_unlink(m_SemaphoreName);
}
}
void MessagePasserImpl::Add(IMessage* msg)
@ -57,23 +98,8 @@ void MessagePasserImpl::Query(QueryMessage* qry, void(* UNUSED(timeoutCallback)
if (m_Trace)
debug_printf("%8.3f add query: %s\n", get_time(), qry->GetName());
// Initialise a semaphore, so we can block until the query has been handled
int err = 0;
sem_t* psem = (sem_t*) SEM_FAILED;
//sem_t sem;
//psem = &sem;
//err = sem_init(psem, 0, 0);
const char* sem_name = "/tmp/atlas";
psem = sem_open(sem_name, O_CREAT, 0777, 0);
err = errno;
if (psem == (sem_t*) SEM_FAILED)
{
// Probably-fatal error
debug_printf("errno: %d (%s)\n", err, strerror(err));
debug_warn("sem_init failed");
return;
}
qry->m_Semaphore = (void*)psem;
// Set the semaphore, so we can block until the query has been handled
qry->m_Semaphore = static_cast<void*>(m_Semaphore);
m_Mutex.Lock();
m_Queue.push(qry);
@ -113,7 +139,8 @@ void MessagePasserImpl::Query(QueryMessage* qry, void(* UNUSED(timeoutCallback)
// while (0 != (err = sem_timedwait(psem, &abs_timeout)))
// #endif
while (0 != (err = sem_wait(psem)))
int err;
while (0 != (err = sem_wait(m_Semaphore)))
{
// If timed out, call callback and try again
// if (errno == ETIMEDOUT)
@ -129,9 +156,6 @@ void MessagePasserImpl::Query(QueryMessage* qry, void(* UNUSED(timeoutCallback)
// Clean up
qry->m_Semaphore = NULL;
//sem_destroy(psem);
sem_close(psem);
sem_unlink(sem_name);
}
bool MessagePasserImpl::IsEmpty()

6
source/tools/atlas/GameInterface/MessagePasserImpl.h
View File

@ -1,12 +1,14 @@
#include "MessagePasser.h"
#include "ps/ThreadUtil.h"
#include "ps/CStr.h"
#include <queue>
class MessagePasserImpl : public AtlasMessage::MessagePasser
class MessagePasserImpl : public AtlasMessage::MessagePasser, boost::noncopyable
{
public:
MessagePasserImpl();
~MessagePasserImpl();
virtual void Add(AtlasMessage::IMessage* msg);
virtual AtlasMessage::IMessage* Retrieve();
virtual void Query(AtlasMessage::QueryMessage* qry, void(*timeoutCallback)());
@ -17,6 +19,8 @@ public:
private:
CMutex m_Mutex;
CStr m_SemaphoreName;
sem_t* m_Semaphore;
std::queue<AtlasMessage::IMessage*> m_Queue;
bool m_Trace;
};