1 /* $Id$ */

     2 

     3 /** @file thread_pthread.cpp POSIX pthread implementation of Threads. */

     4 

     5 #include "stdafx.h"

     6 #include "thread.h"

     7 #include "debug.h"

     8 #include "core/alloc_func.hpp"

     9 #include <stdlib.h>

    10 #include <pthread.h>

    11 #include <semaphore.h>

    12 #include <unistd.h>

    13 

    14 /**

    15  * POSIX pthread version for ThreadObject.

    16  */

    17 class ThreadObject_pthread : public ThreadObject {

    18 private:

    19 	pthread_t m_thr;             ///< System thread identifier.

    20 	OTTDThreadFunc m_proc;       ///< External thread procedure.

    21 	void     *m_param;           ///< Parameter for the external thread procedure.

    22 	bool      m_attached;        ///< True if the ThreadObject was attached to an existing thread.

    23 	sem_t     m_sem_start;       ///< Here the new thread waits before it starts.

    24 	sem_t     m_sem_stop;        ///< Here the other thread can wait for this thread to end.

    25 

    26 public:

    27 	/**

    28 	 * Create a pthread and start it, calling proc(param).

    29 	 */

    30 	ThreadObject_pthread(OTTDThreadFunc proc, void *param) :

    31 		m_thr(0),

    32 		m_proc(proc),

    33 		m_param(param),

    34 		m_attached(false)

    35 	{

    36 		sem_init(&m_sem_start, 0, 0);

    37 		sem_init(&m_sem_stop, 0, 0);

    38 

    39 		pthread_create(&m_thr, NULL, &stThreadProc, this);

    40 		sem_post(&m_sem_start);

    41 	}

    42 

    43 	/**

    44 	 * Create a pthread and attach current thread to it.

    45 	 */

    46 	ThreadObject_pthread() :

    47 		m_thr(0),

    48 		m_proc(NULL),

    49 		m_param(0),

    50 		m_attached(true)

    51 	{

    52 		sem_init(&m_sem_start, 0, 0);

    53 		sem_init(&m_sem_stop, 0, 0);

    54 

    55 		m_thr = pthread_self();

    56 	}

    57 

    58 	/* virtual */ ~ThreadObject_pthread()

    59 	{

    60 		sem_destroy(&m_sem_stop);

    61 		sem_destroy(&m_sem_start);

    62 	};

    63 

    64 	/* virtual */ bool IsRunning()

    65 	{

    66 		return m_thr != 0;

    67 	}

    68 

    69 	/* virtual */ bool WaitForStop()

    70 	{

    71 		/* You can't wait on yourself */

    72 		assert(!IsCurrent());

    73 		/* If the thread is not running, waiting is over */

    74 		if (!IsRunning()) return true;

    75 

    76 		int ret = sem_wait(&m_sem_stop);

    77 		if (ret == 0) {

    78 			/* We have passed semaphore so increment it again */

    79 			sem_post(&m_sem_stop);

    80 			return true;

    81 		}

    82 		return false;

    83 	}

    84 

    85 	/* virtual */ bool Exit()

    86 	{

    87 		/* You can only exit yourself */

    88 		assert(IsCurrent());

    89 		/* If the thread is not running, we are already closed */

    90 		if (!IsRunning()) return false;

    91 

    92 		/* For now we terminate by throwing an error, gives much cleaner cleanup */

    93 		throw 0;

    94 	}

    95 

    96 	/* virtual */ void *Join()

    97 	{

    98 		/* You cannot join yourself */

    99 		assert(!IsCurrent());

   100 

   101 		void *ret;

   102 		pthread_join(m_thr, &ret);

   103 		m_thr = 0;

   104 

   105 		return ret;

   106 	}

   107 

   108 	/* virtual */ bool IsCurrent()

   109 	{

   110 		return pthread_self() == m_thr;

   111 	}

   112 

   113 	/* virtual */ uint GetId()

   114 	{

   115 		return (uint)m_thr;

   116 	}

   117 

   118 private:

   119 	/**

   120 	 * On thread creation, this function is called, which calls the real startup

   121 	 *  function. This to get back into the correct instance again.

   122 	 */

   123 	static void *stThreadProc(void *thr)

   124 	{

   125 		return ((ThreadObject_pthread *)thr)->ThreadProc();

   126 	}

   127 

   128 	/**

   129 	 * A new thread is created, and this function is called. Call the custom

   130 	 *  function of the creator of the thread.

   131 	 */

   132 	void *ThreadProc()

   133 	{

   134 		/* The new thread stops here so the calling thread can complete pthread_create() call */

   135 		sem_wait(&m_sem_start);

   136 

   137 		/* Call the proc of the creator to continue this thread */

   138 		try {

   139 			m_proc(m_param);

   140 		} catch (...) {

   141 		}

   142 

   143 		/* Notify threads waiting for our completion */

   144 		sem_post(&m_sem_stop);

   145 

   146 		return NULL;

   147 	}

   148 };

   149 

   150 /* static */ ThreadObject *ThreadObject::New(OTTDThreadFunc proc, void *param)

   151 {

   152 	return new ThreadObject_pthread(proc, param);

   153 }

   154 

   155 /* static */ ThreadObject *ThreadObject::AttachCurrent()

   156 {

   157 	return new ThreadObject_pthread();

   158 }

   159 

   160 /* static */ uint ThreadObject::CurrentId()

   161 {

   162 	return (uint)pthread_self();

   163 }

   164 

   165 

   166 /**

   167  * POSIX pthread version of ThreadSemaphore.

   168  */

   169 class ThreadSemaphore_pthread : public ThreadSemaphore {

   170 private:

   171 	sem_t m_sem;

   172 

   173 public:

   174 	ThreadSemaphore_pthread()

   175 	{

   176 		sem_init(&m_sem, 0, 0);

   177 	}

   178 

   179 	/* virtual */ ~ThreadSemaphore_pthread()

   180 	{

   181 		sem_destroy(&m_sem);

   182 	}

   183 

   184 	/* virtual */ void Set()

   185 	{

   186 		int val = 0;

   187 		if (sem_getvalue(&m_sem, &val) == 0 && val == 0) sem_post(&m_sem);

   188 	}

   189 

   190 	/* virtual */ void Wait()

   191 	{

   192 		sem_wait(&m_sem);

   193 	}

   194 };

   195 

   196 /* static */ ThreadSemaphore *ThreadSemaphore::New()

   197 {

   198 	return new ThreadSemaphore_pthread();

   199 }