X-Git-Url: http://info.iut-bm.univ-fcomte.fr/pub/gitweb/simgrid.git/blobdiff_plain/de6f834747f9af2af9f110ee3ba3bb9f3f0d01f3..59a1aff0fbe12fa74b7d0b9fb46492fa7a822acc:/src/xbt/context.c

diff --git a/src/xbt/context.c b/src/xbt/context.c
index c7f59edb76..5ab348db85 100644
--- a/src/xbt/context.c
+++ b/src/xbt/context.c
@@ -3,7 +3,7 @@
 /* a fast and simple context switching library                              */
 
 /* Copyright (c) 2004 Arnaud Legrand.                                       */
-/* Copyright (c) 2004 Martin Quinson.                                       */
+/* Copyright (c) 2004, 2005 Martin Quinson.                                 */
 /* All rights reserved.                                                     */
 
 /* This program is free software; you can redistribute it and/or modify it
@@ -14,246 +14,296 @@
 #include "xbt/error.h"
 #include "xbt/dynar.h"
 #include "gras_config.h"
+
 XBT_LOG_NEW_DEFAULT_SUBCATEGORY(context, xbt, "Context");
 
-#ifndef HAVE_UCONTEXT_H
+#define VOIRP(expr) DEBUG1("  {" #expr " = %p }", expr)
+
+static xbt_context_t current_context = NULL;
+static xbt_context_t init_context = NULL;
+static xbt_swag_t context_to_destroy = NULL;
+static xbt_swag_t context_living = NULL;
+
+#ifndef USE_PTHREADS /* USE_PTHREADS and USE_CONTEXT are exclusive */
+# ifndef USE_UCONTEXT
 /* don't want to play with conditional compilation in automake tonight, sorry.
    include directly the c file from here when needed. */
-# include "context_win32.c" 
+#  include "context_win32.c" 
+# endif
 #endif
 
-static context_t current_context = NULL;
-static xbt_dynar_t context_to_destroy = NULL;
-
-void context_init(void)
+static void __xbt_context_yield(xbt_context_t context)
 {
-  if(!current_context) {
-    current_context = xbt_new0(s_context_t,1);
-    context_to_destroy = xbt_dynar_new(sizeof(context_t),xbt_free);
+  int return_value = 0;
+
+  xbt_assert0(current_context,"You have to call context_init() first.");
+  
+  DEBUG2("--------- current_context (%p) is yielding to context(%p) ---------",
+	 current_context,context);
+
+#ifdef USE_PTHREADS
+  if (context) {
+    xbt_context_t self = current_context;
+    DEBUG0("**** Locking ****");
+    pthread_mutex_lock(&(context->mutex));
+    DEBUG0("**** Updating current_context ****");
+    current_context = context;
+    DEBUG0("**** Releasing the prisonner ****");
+    pthread_cond_signal(&(context->cond));
+    DEBUG0("**** Going to jail ****");
+    pthread_cond_wait(&(context->cond), &(context->mutex));
+    DEBUG0("**** Unlocking ****");
+    pthread_mutex_unlock(&(context->mutex));
+    DEBUG0("**** Updating current_context ****");
+    current_context = self;
+  }
+#else
+  if(current_context)
+    VOIRP(current_context->save);
+
+  VOIRP(context);
+  if(context) VOIRP(context->save);
+  if (context) {
+    if(context->save==NULL) {
+      DEBUG0("**** Yielding to somebody else ****");
+      DEBUG2("Saving current_context value (%p) to context(%p)->save",current_context,context);
+      context->save = current_context ;
+      DEBUG1("current_context becomes  context(%p) ",context);
+      current_context = context ;
+      DEBUG1("Current position memorized (context->save). Jumping to context (%p)",context);
+      return_value = swapcontext (&(context->save->uc), &(context->uc));
+      xbt_assert0((return_value==0),"Context swapping failure");
+      DEBUG1("I am (%p). Coming back\n",context);
+    } else {
+      xbt_context_t old_context = context->save ;
+      DEBUG0("**** Back ! ****");
+      DEBUG2("Setting current_context (%p) to context(%p)->save",current_context,context);
+      current_context = context->save ;
+      DEBUG1("Setting context(%p)->save to NULL",context);
+      context->save = NULL ;
+      DEBUG2("Current position memorized (%p). Jumping to context (%p)",context,old_context);
+      return_value = swapcontext (&(context->uc), &(old_context->uc));
+      xbt_assert0((return_value==0),"Context swapping failure");
+      DEBUG1("I am (%p). Coming back\n",context);
+    }
   }
+#endif
+  return;
 }
 
-void context_empty_trash(void)
+static void xbt_context_destroy(xbt_context_t context)
 {
-  xbt_dynar_reset(context_to_destroy);
+#ifdef USE_PTHREADS
+  xbt_free(context->thread);
+  pthread_mutex_destroy(&(context->mutex));
+  pthread_cond_destroy(&(context->cond));
+#endif
+  free(context);
+  return;
 }
 
 static void *__context_wrapper(void *c)
 {
-  context_t context = c;
+  xbt_context_t context = c;
   int i;
 
-/*   msg_global->current_process = process; */
+#ifdef USE_PTHREADS
+  DEBUG0("**** Lock ****");
+  pthread_mutex_lock(&(context->mutex));
+  DEBUG0("**** Releasing the prisonner ****");
+  pthread_cond_signal(&(context->cond));
+  DEBUG0("**** Going to Jail ****");
+  pthread_cond_wait(&(context->cond), &(context->mutex));
+  DEBUG0("**** Unlocking ****");
+  pthread_mutex_unlock(&(context->mutex));
+#endif
+
+  if(context->startup_func)
+    context->startup_func(context->startup_arg);
 
-  /*  WARNING("Calling the main function"); */
+   DEBUG0("Calling the main function");
   (context->code) (context->argc,context->argv);
 
   for(i=0;i<context->argc; i++) 
-    if(context->argv[i]) xbt_free(context->argv[i]);
-  if(context->argv) xbt_free(context->argv);
+    if(context->argv[i]) free(context->argv[i]);
+  if(context->argv) free(context->argv);
 
-  xbt_dynar_push(context_to_destroy, &context);
+  if(context->cleanup_func)
+    context->cleanup_func(context->cleanup_arg);
 
-  context_yield(context);
+  xbt_swag_remove(context, context_living);
+  xbt_swag_insert(context, context_to_destroy);
 
+  __xbt_context_yield(context);
+  xbt_assert0(0,"You're cannot be here!");
   return NULL;
 }
 
-void context_start(context_t context) 
+/** \name Functions 
+ *  \ingroup XBT_context
+ */
+/* @{ */
+/** Context module initialization
+ *
+ * \warning It has to be called before using any other function of this module.
+ */
+void xbt_context_init(void)
+{
+  if(!current_context) {
+    current_context = init_context = xbt_new0(s_xbt_context_t,1);
+    context_to_destroy = xbt_swag_new(xbt_swag_offset(*current_context,hookup));
+    context_living = xbt_swag_new(xbt_swag_offset(*current_context,hookup));
+    xbt_swag_insert(init_context, context_living);
+  }
+}
+
+/** Garbage collection
+ *
+ * Should be called some time to time to free the memory allocated for contexts
+ * that have finished executing their main functions.
+ */
+void xbt_context_empty_trash(void)
 {
+  xbt_context_t context=NULL;
 
-/*   TBX_FIFO_insert(msg_global->process, process); */
-/*   TBX_FIFO_insert(msg_global->process_to_run, process); */
+  while((context=xbt_swag_extract(context_to_destroy)))
+    xbt_context_destroy(context);
+}
 
-  /*  WARNING("Assigning __MSG_process_launcher to context (%p)",context); */
+/** 
+ * \param context the context to start
+ * 
+ * Calling this function prepares \a context to be run. It will 
+   however run effectively only when calling #xbt_context_schedule
+ */
+void xbt_context_start(xbt_context_t context) 
+{
+#ifdef USE_PTHREADS
+  /* Launch the thread */
+  DEBUG0("**** Locking ****");
+  pthread_mutex_lock(&(context->mutex));
+  DEBUG0("**** Pthread create ****");
+  xbt_assert0(!pthread_create(context->thread, NULL, __context_wrapper, context),
+	      "Unable to create a thread.");
+  DEBUG0("**** Going to jail ****");
+  pthread_cond_wait(&(context->cond), &(context->mutex));
+  DEBUG0("**** Unlocking ****");
+  pthread_mutex_unlock(&(context->mutex));  
+#else
   makecontext (&(context->uc), (void (*) (void)) __context_wrapper,
 	       1, context);
-
+#endif
   return;
 }
 
-context_t context_create(context_function_t code,
-			 int argc, char *argv[])
+/** 
+ * \param code a main function
+ * \param startup_func a function to call when running the context for
+ *      the first time and just before the main function \a code
+ * \param startup_arg the argument passed to the previous function (\a startup_func)
+ * \param cleanup_func a function to call when running the context, just after 
+        the termination of the main function \a code
+ * \param cleanup_arg the argument passed to the previous function (\a cleanup_func)
+ * \param argc first argument of function \a code
+ * \param argv seconde argument of function \a code
+ */
+xbt_context_t xbt_context_new(xbt_context_function_t code, 
+			      void_f_pvoid_t startup_func, void *startup_arg,
+			      void_f_pvoid_t cleanup_func, void *cleanup_arg,
+			      int argc, char *argv[])
 {
-  context_t res = NULL;
-
-  res = xbt_new0(s_context_t,1);
-
-  /*  WARNING("Initializing context (%p)",res); */
+  xbt_context_t res = NULL;
 
-  xbt_assert0(getcontext(&(res->uc))==0,"Error in context saving.");
+  res = xbt_new0(s_xbt_context_t,1);
 
-  /*  VOIRP(res->uc); */
   res->code = code;
-  res->uc.uc_link = &(current_context->uc); /* FIXME LATER */
+#ifdef USE_PTHREADS
+  res->thread = xbt_new0(pthread_t,1);
+  xbt_assert0(!pthread_mutex_init(&(res->mutex), NULL), "Mutex initialization error");
+  xbt_assert0(!pthread_cond_init(&(res->cond), NULL), "Condition initialization error");
+#else
+  /* FIXME: strerror is not thread safe */
+  xbt_assert2(getcontext(&(res->uc))==0,"Error in context saving: %d (%s)", errno, strerror(errno));
+  res->uc.uc_link = NULL;
+  /*   res->uc.uc_link = &(current_context->uc); */
   /* WARNING : when this context is over, the current_context (i.e. the 
-     father), is awaken... May result in bugs later.*/
+     father), is awaken... Theorically, the wrapper should prevent using 
+     this feature. */
   res->uc.uc_stack.ss_sp = res->stack;
   res->uc.uc_stack.ss_size = STACK_SIZE;
-  return res;
-}
+#endif
+  res->argc = argc;
+  res->argv = argv;
+  res->startup_func = startup_func;
+  res->startup_arg = startup_arg;
+  res->cleanup_func = cleanup_func;
+  res->cleanup_arg = cleanup_arg;
 
-static void context_destroy(context_t context)
-{
-  xbt_free(context);
+  xbt_swag_insert(res, context_living);
 
-  return;
+  return res;
 }
 
-void context_yield(context_t context)
+/** 
+ * Calling this function makes the current context yield. The context
+ * that scheduled it returns from xbt_context_schedule as if nothing
+ * had happened.
+ */
+void xbt_context_yield(void)
 {
-
-  xbt_assert0(current_context,"You have to call context_init() first.");
-
-  /*   __MSG_context_init(); */
-  /*  fprintf(stderr,"\n"); */
-  /*  WARNING("--------- current_context (%p) is yielding to context(%p) ---------",current_context,context); */
-  /*  VOIRP(current_context); */
-  /*  if(current_context) VOIRP(current_context->save); */
-  /*  VOIRP(context); */
-  /*  if(context) VOIRP(context->save); */
-
-  if (context) {
-/*     m_process_t self = msg_global->current_process; */
-    if(context->save==NULL) {
-      /*      WARNING("**** Yielding to somebody else ****"); */
-      /*      WARNING("Saving current_context value (%p) to context(%p)->save",current_context,context); */
-      context->save = current_context ;
-      context->uc.uc_link = &(current_context->uc);
-      /*      WARNING("current_context becomes  context(%p) ",context); */
-      current_context = context ;
-      /*      WARNING("Current position memorized (context->save). Jumping to context (%p)",context); */
-      if(!swapcontext (&(context->save->uc), &(context->uc))) 
-	xbt_assert0(0,"Context swapping failure");
-      /*      WARNING("I am (%p). Coming back\n",context); */
-    } else {
-      context_t old_context = context->save ;
-      /*      WARNING("**** Back ! ****"); */
-      /*      WARNING("Setting current_context (%p) to context(%p)->save",current_context,context); */
-      current_context = context->save ;
-      /*      WARNING("Setting context(%p)->save to NULL",current_context,context); */
-      context->save = NULL ;
-      /*      WARNING("Current position memorized (%p). Jumping to context (%p)",context,old_context); */
-      if(!swapcontext (&(context->uc), &(old_context->uc)) ) 
-	xbt_assert0(0,"Context swapping failure");
-      /*      WARNING("I am (%p). Coming back\n",context); */
-    }
-/*     msg_global->current_process = self; */
-  }
-
-  return;
+  __xbt_context_yield(current_context);
 }
 
-
-/****************************** PTHREADS ***************************/
-
-/* FIXME: this is dead code as we don't really need it.
-   If you have pthreads, you have contexts (which are better) */
-
-#if 0 
-#ifdef HAVE_LIBPTHREAD  /* Nevermind, let's use pthreads... */
-
-static void *__MSG_process_launcher(void *p)
+/** 
+ * \param context the winner
+ *
+ * Calling this function blocks the current context and schedule \a context.  
+ * When \a context will call xbt_context_yield, it will return
+ * to this function as if nothing had happened.
+ */
+void xbt_context_schedule(xbt_context_t context)
 {
-  m_process_t process = (m_process_t) p;
-  sim_data_process_t sim_data = process->simdata;
-  context_t context = NULL;
-  int i;
-  msg_global->current_process = process;
-  TBX_FIFO_insert(msg_global->process, process);
-
-  TBX_FIFO_insert(msg_global->process_to_run, process);
-/*   pthread_mutex_lock(&(sim_data->context->mutex)); */
-  __MSG_context_yield(sim_data->context);
-
-  (*sim_data->context->code) (sim_data->argc,sim_data->argv);
-
-  TBX_FIFO_remove(msg_global->process, process);
-  TBX_FIFO_remove(msg_global->process_to_run, process);
-
-  /* Free blocked process if any */
-/*   pthread_mutex_lock(&(sim_data->context->mutex)); */
-/*   pthread_cond_signal(&(sim_data->context->cond)); */
-/*   pthread_mutex_unlock(&(sim_data->context->mutex)); */
-
-  context = sim_data->context;
-
-  for(i=0;i<sim_data->argc; i++) 
-    if(sim_data->argv[i]) FREE(sim_data->argv[i]);
-  if(sim_data->argv) FREE(sim_data->argv);
-  if(process->name) FREE(process->name);
-  FREE(sim_data);
-  FREE(process);
-
-  TBX_FIFO_insert(msg_global->context_to_destroy,context);
-  __MSG_context_yield(context);
-/*   __MSG_context_destroy(&context); */
-
-  return NULL;
+  xbt_assert0((current_context==init_context),
+	      "You are not supposed to run this function here!");
+  __xbt_context_yield(context);
 }
 
-MSG_error_t __MSG_context_start(m_process_t process) 
-{
-  sim_data_process_t sim_data = NULL;
+/** 
+ * This function kill all existing context and free all the memory
+ * that has been allocated in this module.
+ */
+void xbt_context_exit(void) {
+  xbt_context_t context=NULL;
 
-  sim_data = process->simdata;
+  xbt_context_empty_trash();
+  xbt_swag_free(context_to_destroy);
 
-  pthread_mutex_lock(&(sim_data->context->mutex));
+  while((context=xbt_swag_extract(context_living)))
+    xbt_context_free(context);
 
-  /* Launch the thread */
-  if (pthread_create(sim_data->context->thread, NULL, __MSG_process_launcher,
-		     process) != 0) {
-    WARNING("Unable to create a thread.");
-    return MSG_FATAL;
-  }
-  pthread_cond_wait(&(sim_data->context->cond), &(sim_data->context->mutex));
-  pthread_mutex_unlock(&(sim_data->context->mutex));
-/*   __MSG_context_yield(sim_data->context); */
+  xbt_swag_free(context_living);
 
-  return MSG_OK;
+  init_context = current_context = NULL ;
 }
 
-context_t __MSG_context_create(m_process_code_t code)
+/** 
+ * \param context poor victim
+ *
+ * This function simply kills \a context... scarry isn't it ?
+ */
+void xbt_context_free(xbt_context_t context)
 {
-  context_t res = NULL;
-
-  res = CALLOC(1, sizeof(struct s_context));
+  int i ;
 
-  res->code = code;
-  res->thread = CALLOC(1, sizeof(pthread_t));
-  if (pthread_mutex_init(&(res->mutex), NULL) != 0)
-    FAILURE("Mutex initialization error");
-  if (pthread_cond_init(&(res->cond), NULL) != 0)
-    FAILURE("Condition initialization error");
-
-  return res;
-}
-
-MSG_error_t __MSG_context_destroy(context_t * context)
-{
-  ASSERT(((context != NULL) && (*context != NULL)), "Invalid parameters");
-
-  FREE((*context)->thread);
-  pthread_mutex_destroy(&((*context)->mutex));
-  pthread_cond_destroy(&((*context)->cond));
-
-  FREE(*context);
-  *context = NULL;
-
-  return MSG_OK;
-}
+  xbt_swag_remove(context, context_living);  
+  for(i=0;i<context->argc; i++) 
+    if(context->argv[i]) free(context->argv[i]);
+  if(context->argv) free(context->argv);
+  
+  if(context->cleanup_func)
+    context->cleanup_func(context->cleanup_arg);
+  xbt_context_destroy(context);
 
-MSG_error_t __MSG_context_yield(context_t context)
-{
-  if (context) {
-    m_process_t self = msg_global->current_process;
-    pthread_mutex_lock(&(context->mutex));
-    pthread_cond_signal(&context->cond);
-    pthread_cond_wait(&context->cond, &context->mutex);
-    pthread_mutex_unlock(&(context->mutex));
-    msg_global->current_process = self;
-  }
-  return MSG_OK;
+  return;
 }
-#endif /* HAVE_LIBPTHREAD */
-#endif /* 0 */
+/* @} */