libguile/coop-defs.h

   1 /* classes: h_files */
   2
   3 #ifndef COOP_DEFSH
   4 #define COOP_DEFSH
   5
   6 /*      Copyright (C) 1996, 1997, 1998 Free Software Foundation, Inc.
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation; either version 2, or (at your option)
  11  * any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this software; see the file COPYING.  If not, write to
  20  * the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
  21  * Boston, MA 02111-1307 USA
  22  *
  23  * As a special exception, the Free Software Foundation gives permission
  24  * for additional uses of the text contained in its release of GUILE.
  25  *
  26  * The exception is that, if you link the GUILE library with other files
  27  * to produce an executable, this does not by itself cause the
  28  * resulting executable to be covered by the GNU General Public License.
  29  * Your use of that executable is in no way restricted on account of
  30  * linking the GUILE library code into it.
  31  *
  32  * This exception does not however invalidate any other reasons why
  33  * the executable file might be covered by the GNU General Public License.
  34  *
  35  * This exception applies only to the code released by the
  36  * Free Software Foundation under the name GUILE.  If you copy
  37  * code from other Free Software Foundation releases into a copy of
  38  * GUILE, as the General Public License permits, the exception does
  39  * not apply to the code that you add in this way.  To avoid misleading
  40  * anyone as to the status of such modified files, you must delete
  41  * this exception notice from them.
  42  *
  43  * If you write modifications of your own for GUILE, it is your choice
  44  * whether to permit this exception to apply to your modifications.
  45  * If you do not wish that, delete this exception notice.  */
  46
  47 /* Software engineering face-lift by Greg J. Badros, 11-Dec-1999,
  48    gjb@cs.washington.edu, http://www.cs.washington.edu/homes/gjb */
  49 \f
  50
  51 # ifdef TIME_WITH_SYS_TIME
  52 #  include <sys/time.h>
  53 #  include <time.h>
  54 # else
  55 #  ifdef HAVE_SYS_TIME_H
  56 #   include <sys/time.h>
  57 #  else
  58 #   ifdef HAVE_TIME_H
  59 #    include <time.h>
  60 #   endif
  61 #  endif
  62 # endif
  63
  64 #ifdef GUILE_ISELECT
  65 #include "iselect.h"
  66 #endif
  67
  68 /* This file is included by threads.h, which, in turn, is included by
  69    libguile.h while coop-threads.h only is included by
  70    coop-threads.c. */
  71
  72 /* The coop_t struct must be declared here, since macros in this file
  73    refer to the data member. */
  74
  75 /* The notion of a thread is merged with the notion of a queue.
  76    Thread stuff: thread status (sp) and stuff to use during
  77    (re)initialization.  Queue stuff: next thread in the queue
  78    (next). */
  79
  80 struct qt_t;
  81
  82 typedef struct coop_t {
  83   struct qt_t *sp;       /* QuickThreads handle. */
  84   void *sto;             /* `malloc'-allocated stack. */
  85
  86   struct coop_t *next;    /* Next thread in the queue. */
  87
  88   struct coop_t *all_next;
  89   struct coop_t *all_prev;
  90
  91   void *data;            /* Thread local data */
  92
  93   void *base;            /* Base of stack */
  94   void *top;             /* Top of stack */
  95
  96   void *joining;         /* A queue of threads waiting to join this
  97                             thread */
  98
  99 #ifdef GUILE_ISELECT
 100   int nfds;
 101   SELECT_TYPE *readfds;
 102   SELECT_TYPE *writefds;
 103   SELECT_TYPE *exceptfds;
 104   int timeoutp;
 105   struct timeval wakeup_time;   /* Time to stop sleeping */
 106   int _errno;
 107   int retval;
 108 #else
 109   time_t wakeup_time;    /* Time to stop sleeping */
 110 #endif
 111
 112 } coop_t;
 113
 114 /* A queue is a circular list of threads.  The queue head is a
 115    designated list element.  If this is a uniprocessor-only
 116    implementation we can store the `main' thread in this, but in a
 117    multiprocessor there are several `heavy' threads but only one run
 118    queue.  A fancier implementation might have private run queues,
 119    which would lead to a simpler (trivial) implementation */
 120
 121 typedef struct coop_q_t {
 122   coop_t t;
 123   coop_t *tail;
 124 } coop_q_t;
 125
 126 /* A Mutex variable is made up of a owner thread, and a queue of threads
 127    waiting on the mutex */
 128
 129 typedef struct coop_m {
 130   coop_t *owner;          /* Mutex owner */
 131   coop_q_t waiting;      /* Queue of waiting threads */
 132 } coop_m;
 133
 134 typedef coop_m scm_mutex_t;
 135
 136 extern int coop_mutex_init (coop_m*);
 137 extern int coop_mutex_lock (coop_m*);
 138 extern int coop_mutex_unlock (coop_m*);
 139 extern int coop_mutex_destroy (coop_m*);
 140 #define scm_mutex_init coop_mutex_init
 141 #define scm_mutex_lock coop_mutex_lock
 142 #define scm_mutex_unlock coop_mutex_unlock
 143 #define scm_mutex_destroy coop_mutex_destroy
 144
 145 /* A Condition variable is made up of a list of threads waiting on the
 146    condition. */
 147
 148 typedef struct coop_c {
 149   coop_q_t waiting;      /* Queue of waiting threads */
 150 } coop_c;
 151
 152 typedef coop_c scm_cond_t;
 153
 154 extern int coop_condition_variable_init (coop_c*);
 155 extern int coop_condition_variable_wait_mutex (coop_c*, coop_m*);
 156 extern int coop_condition_variable_signal (coop_c*);
 157 extern int coop_condition_variable_destroy (coop_c*);
 158 #define scm_cond_init(cond, attr) coop_condition_variable_init (cond)
 159 #define scm_cond_wait coop_condition_variable_wait_mutex
 160 #define scm_cond_signal coop_condition_variable_signal
 161 #define scm_cond_destroy coop_condition_variable_destroy
 162
 163 extern coop_t *coop_global_curr;        /* Currently-executing thread. */
 164
 165 extern void coop_join (coop_t *t);
 166 extern void coop_yield (void);
 167
 168 extern size_t scm_switch_counter;
 169 extern size_t scm_thread_count;
 170
 171 \f
 172 /* Some iselect functions.  */
 173
 174 /* I'm not sure whether these three declarations should be here.
 175    They're really defined in iselect.c, so you'd think they'd go in
 176    iselect.h, but they use coop_t, defined above, which uses things
 177    defined in iselect.h.  Basically, we're making at best a flailing
 178    (and failing) attempt at modularity here, and I don't have time to
 179    rethink this at the moment.  This code awaits a Hero.  --JimB */
 180 extern coop_t *coop_next_runnable_thread (void);
 181 extern coop_t *coop_wait_for_runnable_thread_now (struct timeval *);
 182 extern coop_t *coop_wait_for_runnable_thread (void);
 183
 184
 185 \f
 186
 187 /* Cooperative threads don't need to have these defined */
 188
 189 #define SCM_THREAD_CRITICAL_SECTION_START
 190 #define SCM_THREAD_CRITICAL_SECTION_END
 191
 192 \f
 193
 194 #define SCM_NO_CRITICAL_SECTION_OWNER 0
 195 #define SCM_THREAD_SWITCH_COUNT       50 /* was 10 /mdj */
 196
 197 \f
 198
 199 #define SCM_THREAD_DEFER
 200 #define SCM_THREAD_ALLOW
 201 #define SCM_THREAD_REDEFER
 202 #define SCM_THREAD_REALLOW_1
 203 #define SCM_THREAD_REALLOW_2
 204
 205 #if 0
 206 #define SCM_THREAD_SWITCHING_CODE \
 207 do { \
 208   if (scm_thread_count > 1) \
 209     coop_yield(); \
 210 } while (0)
 211
 212 #else
 213 #define SCM_THREAD_SWITCHING_CODE \
 214 do { \
 215   if (scm_thread_count > 1) \
 216   { \
 217     scm_switch_counter--; \
 218     if (scm_switch_counter == 0) \
 219       { \
 220         scm_switch_counter = SCM_THREAD_SWITCH_COUNT; \
 221         coop_yield(); \
 222       } \
 223   } \
 224 } while (0)
 225
 226 #endif
 227
 228 #define SCM_THREAD_LOCAL_DATA (coop_global_curr->data)
 229 #define SCM_SET_THREAD_LOCAL_DATA(ptr) (coop_global_curr->data = (ptr))
 230
 231 #endif /* COOP_DEFSH */