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_destroy(xbt_context_t context)
42 void xbt_context_init(void)
44 if(!current_context) {
45 current_context = init_context = xbt_new0(s_xbt_context_t,1);
46 context_to_destroy = xbt_swag_new(xbt_swag_offset(*current_context,hookup));
47 context_living = xbt_swag_new(xbt_swag_offset(*current_context,hookup));
48 xbt_swag_insert(init_context, context_living);
52 void xbt_context_empty_trash(void)
54 xbt_context_t context=NULL;
56 while((context=xbt_swag_extract(context_to_destroy)))
57 xbt_context_destroy(context);
60 static void *__context_wrapper(void *c)
62 xbt_context_t context = c;
65 /* msg_global->current_process = process; */
67 /* WARNING("Calling the main function"); */
68 /* xbt_context_yield(context); */
69 (context->code) (context->argc,context->argv);
71 for(i=0;i<context->argc; i++)
72 if(context->argv[i]) xbt_free(context->argv[i]);
73 if(context->argv) xbt_free(context->argv);
75 xbt_swag_remove(context, context_living);
76 xbt_swag_insert(context, context_to_destroy);
78 xbt_context_yield(context);
83 void xbt_context_start(xbt_context_t context)
85 /* xbt_fifo_insert(msg_global->process, process); */
86 /* xbt_fifo_insert(msg_global->process_to_run, process); */
88 makecontext (&(context->uc), (void (*) (void)) __context_wrapper,
93 xbt_context_t xbt_context_new(xbt_context_function_t code,
94 int argc, char *argv[])
96 xbt_context_t res = NULL;
98 res = xbt_new0(s_xbt_context_t,1);
100 xbt_assert0(getcontext(&(res->uc))==0,"Error in context saving.");
103 res->uc.uc_link = NULL;
104 /* res->uc.uc_link = &(current_context->uc); */
105 /* WARNING : when this context is over, the current_context (i.e. the
106 father), is awaken... Theorically, the wrapper should prevent using
108 res->uc.uc_stack.ss_sp = res->stack;
109 res->uc.uc_stack.ss_size = STACK_SIZE;
111 xbt_swag_insert(res, context_living);
116 void xbt_context_yield(xbt_context_t context)
118 int return_value = 0;
120 xbt_assert0(current_context,"You have to call context_init() first.");
122 /* WARNING("--------- current_context (%p) is yielding to context(%p) ---------",current_context,context); */
123 /* VOIRP(current_context); */
124 /* if(current_context) VOIRP(current_context->save); */
125 /* VOIRP(context); */
126 /* if(context) VOIRP(context->save); */
129 if(context->save==NULL) {
130 /* WARNING("**** Yielding to somebody else ****"); */
131 /* WARNING("Saving current_context value (%p) to context(%p)->save",current_context,context); */
132 context->save = current_context ;
133 /* WARNING("current_context becomes context(%p) ",context); */
134 current_context = context ;
135 /* WARNING("Current position memorized (context->save). Jumping to context (%p)",context); */
136 return_value = swapcontext (&(context->save->uc), &(context->uc));
137 xbt_assert0((return_value==0),"Context swapping failure");
138 /* WARNING("I am (%p). Coming back\n",context); */
140 xbt_context_t old_context = context->save ;
141 /* WARNING("**** Back ! ****"); */
142 /* WARNING("Setting current_context (%p) to context(%p)->save",current_context,context); */
143 current_context = context->save ;
144 /* WARNING("Setting context(%p)->save to NULL",context); */
145 context->save = NULL ;
146 /* WARNING("Current position memorized (%p). Jumping to context (%p)",context,old_context); */
147 return_value = swapcontext (&(context->uc), &(old_context->uc));
148 xbt_assert0((return_value==0),"Context swapping failure");
149 /* WARNING("I am (%p). Coming back\n",context); */
156 void xbt_context_exit(void) {
157 xbt_context_t context=NULL;
159 xbt_context_empty_trash();
160 xbt_swag_free(context_to_destroy);
162 while((context=xbt_swag_extract(context_living)))
163 xbt_context_destroy(context);
165 xbt_swag_free(context_living);
167 init_context = current_context = NULL ;