3 /* a fast and simple context switching library */
5 /* Copyright (c) 2004 Arnaud Legrand. */
6 /* Copyright (c) 2004 Martin Quinson. */
7 /* All rights reserved. */
9 /* This program is free software; you can redistribute it and/or modify it
10 * under the terms of the license (GNU LGPL) which comes with this package. */
13 #include "context_private.h"
14 #include "xbt/error.h"
15 #include "xbt/dynar.h"
16 #include "gras_config.h"
17 XBT_LOG_NEW_DEFAULT_SUBCATEGORY(context, xbt, "Context");
19 /* #define WARNING(format, ...) (fprintf(stderr, "[%s , %s : %d] ", __FILE__, __FUNCTION__, __LINE__),\ */
20 /* fprintf(stderr, format, ## __VA_ARGS__), \ */
21 /* fprintf(stderr, "\n")) */
22 /* #define VOIRP(expr) WARNING(" {" #expr " = %p }", expr) */
24 #ifndef HAVE_UCONTEXT_H
25 /* don't want to play with conditional compilation in automake tonight, sorry.
26 include directly the c file from here when needed. */
27 # include "context_win32.c"
30 static xbt_context_t current_context = NULL;
31 static xbt_context_t init_context = NULL;
32 static xbt_swag_t context_to_destroy = NULL;
33 static xbt_swag_t context_living = NULL;
35 static void __xbt_context_yield(xbt_context_t context)
39 xbt_assert0(current_context,"You have to call context_init() first.");
41 /* WARNING("--------- current_context (%p) is yielding to context(%p) ---------",current_context,context); */
42 /* VOIRP(current_context); */
43 /* if(current_context) VOIRP(current_context->save); */
45 /* if(context) VOIRP(context->save); */
48 if(context->save==NULL) {
49 /* WARNING("**** Yielding to somebody else ****"); */
50 /* WARNING("Saving current_context value (%p) to context(%p)->save",current_context,context); */
51 context->save = current_context ;
52 /* WARNING("current_context becomes context(%p) ",context); */
53 current_context = context ;
54 /* WARNING("Current position memorized (context->save). Jumping to context (%p)",context); */
55 return_value = swapcontext (&(context->save->uc), &(context->uc));
56 xbt_assert0((return_value==0),"Context swapping failure");
57 /* WARNING("I am (%p). Coming back\n",context); */
59 xbt_context_t old_context = context->save ;
60 /* WARNING("**** Back ! ****"); */
61 /* WARNING("Setting current_context (%p) to context(%p)->save",current_context,context); */
62 current_context = context->save ;
63 /* WARNING("Setting context(%p)->save to NULL",context); */
64 context->save = NULL ;
65 /* WARNING("Current position memorized (%p). Jumping to context (%p)",context,old_context); */
66 return_value = swapcontext (&(context->uc), &(old_context->uc));
67 xbt_assert0((return_value==0),"Context swapping failure");
68 /* WARNING("I am (%p). Coming back\n",context); */
75 static void xbt_context_destroy(xbt_context_t context)
83 * \ingroup XBT_context
86 /** Context module initialization
88 * \warning It has to be called before using any other function of this module.
90 void xbt_context_init(void)
92 if(!current_context) {
93 current_context = init_context = xbt_new0(s_xbt_context_t,1);
94 context_to_destroy = xbt_swag_new(xbt_swag_offset(*current_context,hookup));
95 context_living = xbt_swag_new(xbt_swag_offset(*current_context,hookup));
96 xbt_swag_insert(init_context, context_living);
100 /** Garbage collection
102 * Should be called some time to time to free the memory allocated for contexts
103 * that have finished executing their main functions.
105 void xbt_context_empty_trash(void)
107 xbt_context_t context=NULL;
109 while((context=xbt_swag_extract(context_to_destroy)))
110 xbt_context_destroy(context);
113 static void *__context_wrapper(void *c)
115 xbt_context_t context = c;
118 /* msg_global->current_process = process; */
120 if(context->startup_func)
121 context->startup_func(context->startup_arg);
123 /* WARNING("Calling the main function"); */
124 /* xbt_context_yield(context); */
125 (context->code) (context->argc,context->argv);
127 for(i=0;i<context->argc; i++)
128 if(context->argv[i]) xbt_free(context->argv[i]);
129 if(context->argv) xbt_free(context->argv);
131 if(context->cleanup_func)
132 context->cleanup_func(context->cleanup_arg);
134 xbt_swag_remove(context, context_living);
135 xbt_swag_insert(context, context_to_destroy);
137 __xbt_context_yield(context);
138 xbt_assert0(0,"You're cannot be here!");
143 * \param context the context to start
145 * Calling this function prepares \a context to be run. It will
146 however run effectively only when calling #xbt_context_schedule
148 void xbt_context_start(xbt_context_t context)
150 /* xbt_fifo_insert(msg_global->process, process); */
151 /* xbt_fifo_insert(msg_global->process_to_run, process); */
153 makecontext (&(context->uc), (void (*) (void)) __context_wrapper,
159 * \param code a main function
160 * \param startup_func a function to call when running the context for
161 * the first time and just before the main function \a code
162 * \param startup_arg the argument passed to the previous function (\a startup_func)
163 * \param cleanup_func a function to call when running the context, just after
164 the termination of the main function \a code
165 * \param cleanup_arg the argument passed to the previous function (\a cleanup_func)
166 * \param argc first argument of function \a code
167 * \param argv seconde argument of function \a code
169 xbt_context_t xbt_context_new(xbt_context_function_t code,
170 void_f_pvoid_t startup_func, void *startup_arg,
171 void_f_pvoid_t cleanup_func, void *cleanup_arg,
172 int argc, char *argv[])
174 xbt_context_t res = NULL;
176 res = xbt_new0(s_xbt_context_t,1);
178 xbt_assert0(getcontext(&(res->uc))==0,"Error in context saving.");
181 res->uc.uc_link = NULL;
184 /* res->uc.uc_link = &(current_context->uc); */
185 /* WARNING : when this context is over, the current_context (i.e. the
186 father), is awaken... Theorically, the wrapper should prevent using
188 res->uc.uc_stack.ss_sp = res->stack;
189 res->uc.uc_stack.ss_size = STACK_SIZE;
190 res->startup_func = startup_func;
191 res->startup_arg = startup_arg;
192 res->cleanup_func = cleanup_func;
193 res->cleanup_arg = cleanup_arg;
195 xbt_swag_insert(res, context_living);
202 * Calling this function makes the current context yield. The context
203 * that scheduled it returns from xbt_context_schedule as if nothing
206 void xbt_context_yield(void)
208 __xbt_context_yield(current_context);
213 * \param context the winner
215 * Calling this function blocks the current context and schedule \a context.
216 * When \a context will call xbt_context_yield, it will return
217 * to this function as if nothing had happened.
219 void xbt_context_schedule(xbt_context_t context)
221 xbt_assert0((current_context==init_context),
222 "You are not supposed to run this function here!");
223 __xbt_context_yield(context);
227 * This function kill all existing context and free all the memory
228 * that has been allocated in this module.
230 void xbt_context_exit(void) {
231 xbt_context_t context=NULL;
233 xbt_context_empty_trash();
234 xbt_swag_free(context_to_destroy);
236 while((context=xbt_swag_extract(context_living)))
237 xbt_context_free(context);
239 xbt_swag_free(context_living);
241 init_context = current_context = NULL ;
245 * \param context poor victim
247 * This function simply kills \a context... scarry isn't it ?
249 void xbt_context_free(xbt_context_t context)
253 xbt_swag_remove(context, context_living);
254 for(i=0;i<context->argc; i++)
255 if(context->argv[i]) xbt_free(context->argv[i]);
256 if(context->argv) xbt_free(context->argv);
258 if(context->cleanup_func)
259 context->cleanup_func(context->cleanup_arg);
260 xbt_context_destroy(context);