try to fix some eThread races

[enigma2.git] / lib / base / thread.cpp

diff --git a/lib/base/thread.cpp b/lib/base/thread.cpp
index b64ba1365bfb2376e69e36ce1da73ffb1614c4bc..ceb50bfe350c3dbab479f9150f066ebdfff3f024 100644 (file)
--- a/lib/base/thread.cpp
+++ b/lib/base/thread.cpp
@@ -7,17 +7,20 @@
 void eThread::thread_completed(void *ptr)
 {
        eThread *p = (eThread*) ptr;
-       eDebug("thread has completed..");
-       p->alive=0;
-       p->thread_finished();
+       p->m_alive = 0;
+
+               /* recover state */
+       if (!p->m_state.value())
+       {
+               p->m_state.up();
+               assert(p->m_state.value() == 1);
+       }
 }
 
 void *eThread::wrapper(void *ptr)
 {
        eThread *p = (eThread*)ptr;
-       p->before_set_thread_alive();
-       p->alive=1;
-       pthread_cleanup_push( thread_completed, (void*)p );
+       pthread_cleanup_push(thread_completed, (void*)p);
        p->thread();
        pthread_exit(0);
        pthread_cleanup_pop(1);
@@ -25,65 +28,95 @@ void *eThread::wrapper(void *ptr)
 }
 
 eThread::eThread()
-       :the_thread(0), alive(0)
+       : the_thread(0), m_alive(0)
 {
 }
 
-void eThread::run( int prio, int policy )
+int eThread::runAsync(int prio, int policy)
 {
-       if (alive)
-       {
-               eDebug("thread already running !!");
-               return;
-       }
+       eDebug("before: %d", m_state.value());
+               /* the thread might already run. */
+       if (sync())
+               return -1;
+       
+       eDebug("after: %d", m_state.value());
+       assert(m_state.value() == 1); /* sync postconditions */
+       assert(!m_alive);
+       m_state.down();
+       
+       m_alive = 1;
+
+               /* start thread. */
        pthread_attr_t attr;
        pthread_attr_init(&attr);
-       if (prio||policy)
+       
+       if (prio || policy)
        {
                struct sched_param p;
                p.__sched_priority=prio;
-               pthread_attr_setschedpolicy(&attr, policy );
+               pthread_attr_setschedpolicy(&attr, policy);
                pthread_attr_setschedparam(&attr, &p);
        }
-       if ( pthread_create(&the_thread, &attr, wrapper, this) )
+       
+       if (pthread_create(&the_thread, &attr, wrapper, this))
        {
+               pthread_attr_destroy(&attr);
+               m_alive = 0;
                eDebug("couldn't create new thread");
-               return;
+               return -1;
        }
+       
        pthread_attr_destroy(&attr);
-       usleep(1000);
-       int timeout=50;
-       while(!alive && timeout--)
-       {
-//             eDebug("waiting for thread start...");
-               usleep(1000*10);
-       }
-       if ( !timeout )
-               eDebug("thread couldn't be started !!!");
+       return 0;
 }                     
 
+int eThread::run(int prio, int policy)
+{
+       if (runAsync(prio, policy))
+               return -1;
+       sync();
+       return 0;
+}
+
 eThread::~eThread()
 {
        kill();
 }
 
+int eThread::sync(void)
+{
+       int res;
+       m_state.down(); /* this might block */
+       res = m_alive;
+       assert(m_state.value() == 0);
+       m_state.up();
+       return res; /* 0: thread is guaranteed not to run. 1: state unknown. */
+}
+
 void eThread::sendSignal(int sig)
 {
-       if ( alive )
-               pthread_kill( the_thread, sig );
+       if (m_alive)
+               pthread_kill(the_thread, sig);
        else
                eDebug("send signal to non running thread");
 }
 
 void eThread::kill(bool sendcancel)
 {
-       if (!the_thread)
+       if (!the_thread) /* already joined */
                return;
-       if ( alive && sendcancel )
+
+       if (sync() && sendcancel)
        {
                eDebug("send cancel to thread");
                pthread_cancel(the_thread);
        }
        eDebug("thread joined %d", pthread_join(the_thread, 0));
-       the_thread=0;
+       the_thread = 0;
+}
+
+void eThread::hasStarted()
+{
+       assert(!m_state.value());
+       m_state.up();
 }