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6b468ba4 MD |
1 | /* Copyright (C) 1995,1996,1997,1998,2000,2001, 2002, 2003 Free Software Foundation, Inc. |
2 | * | |
73be1d9e MV |
3 | * This library is free software; you can redistribute it and/or |
4 | * modify it under the terms of the GNU Lesser General Public | |
5 | * License as published by the Free Software Foundation; either | |
6 | * version 2.1 of the License, or (at your option) any later version. | |
6b468ba4 | 7 | * |
73be1d9e MV |
8 | * This library is distributed in the hope that it will be useful, |
9 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
10 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
11 | * Lesser General Public License for more details. | |
6b468ba4 | 12 | * |
73be1d9e MV |
13 | * You should have received a copy of the GNU Lesser General Public |
14 | * License along with this library; if not, write to the Free Software | |
15 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA | |
16 | */ | |
6b468ba4 MD |
17 | |
18 | ||
19 | \f | |
20 | ||
21 | #include "libguile/_scm.h" | |
22 | #include "libguile/eval.h" | |
23 | #include "libguile/ports.h" | |
24 | #include "libguile/validate.h" | |
25 | #include "libguile/stime.h" | |
26 | #include "libguile/threads.h" | |
27 | ||
28 | #include "libguile/futures.h" | |
29 | ||
30 | #define LINK(list, obj) \ | |
31 | do { \ | |
32 | SCM_SET_FUTURE_NEXT (obj, list); \ | |
33 | list = obj; \ | |
34 | } while (0) | |
35 | ||
36 | #define UNLINK(list, obj) \ | |
37 | do { \ | |
38 | obj = list; \ | |
39 | list = SCM_FUTURE_NEXT (list); \ | |
40 | } while (0) | |
41 | ||
42 | SCM_MUTEX (future_admin_mutex); | |
43 | ||
44 | static SCM futures = SCM_EOL; | |
45 | static SCM young = SCM_EOL; | |
46 | static SCM old = SCM_EOL; | |
47 | static SCM undead = SCM_EOL; | |
48 | ||
49 | static long last_switch; | |
50 | ||
51 | #ifdef SCM_FUTURES_DEBUG | |
52 | static int n_dead = 0; | |
53 | ||
54 | static SCM | |
55 | count (SCM ls) | |
56 | { | |
57 | int n = 0; | |
d2e53ed6 | 58 | while (!scm_is_null (ls)) |
6b468ba4 MD |
59 | { |
60 | ++n; | |
61 | ls = SCM_FUTURE_NEXT (ls); | |
62 | } | |
e11e83f3 | 63 | return scm_from_int (n); |
6b468ba4 MD |
64 | } |
65 | ||
66 | extern SCM scm_future_cache_status (void); | |
67 | ||
68 | SCM_DEFINE (scm_future_cache_status, "future-cache-status", 0, 0, 0, | |
69 | (), | |
70 | "Return a list containing number of futures, youngs, olds, undeads and deads.") | |
71 | #define FUNC_NAME s_scm_future_cache_status | |
72 | { | |
73 | int nd = n_dead; | |
74 | n_dead = 0; | |
75 | return scm_list_5 (count (futures), | |
76 | count (young), | |
77 | count (old), | |
78 | count (undead), | |
e11e83f3 | 79 | scm_from_int (nd)); |
6b468ba4 MD |
80 | } |
81 | #undef FUNC_NAME | |
82 | ||
83 | #endif | |
84 | ||
85 | SCM *scm_loc_sys_thread_handler; | |
86 | ||
87 | SCM_DEFINE (scm_make_future, "make-future", 1, 0, 0, | |
88 | (SCM thunk), | |
89 | "Make a future evaluating THUNK.") | |
90 | #define FUNC_NAME s_scm_make_future | |
91 | { | |
92 | SCM_VALIDATE_THUNK (1, thunk); | |
93 | return scm_i_make_future (thunk); | |
94 | } | |
95 | #undef FUNC_NAME | |
96 | ||
97 | static char *s_future = "future"; | |
98 | ||
99 | static void | |
100 | cleanup (scm_t_future *future) | |
101 | { | |
102 | scm_mutex_destroy (&future->mutex); | |
103 | scm_cond_destroy (&future->cond); | |
104 | scm_gc_free (future, sizeof (*future), s_future); | |
105 | #ifdef SCM_FUTURES_DEBUG | |
106 | ++n_dead; | |
107 | #endif | |
108 | } | |
109 | ||
110 | static SCM | |
111 | future_loop (scm_t_future *future) | |
112 | { | |
113 | scm_mutex_lock (&future->mutex); | |
114 | do { | |
115 | if (future->status == SCM_FUTURE_SIGNAL_ME) | |
116 | scm_cond_broadcast (&future->cond); | |
117 | future->status = SCM_FUTURE_COMPUTING; | |
118 | future->data = (SCM_CLOSUREP (future->data) | |
119 | ? scm_i_call_closure_0 (future->data) | |
120 | : scm_call_0 (future->data)); | |
121 | scm_cond_wait (&future->cond, &future->mutex); | |
122 | } while (!future->die_p); | |
123 | future->status = SCM_FUTURE_DEAD; | |
124 | scm_mutex_unlock (&future->mutex); | |
125 | return SCM_UNSPECIFIED; | |
126 | } | |
127 | ||
128 | static SCM | |
129 | future_handler (scm_t_future *future, SCM key, SCM args) | |
130 | { | |
131 | future->status = SCM_FUTURE_DEAD; | |
132 | scm_mutex_unlock (&future->mutex); | |
133 | return scm_apply_1 (*scm_loc_sys_thread_handler, key, args); | |
134 | } | |
135 | ||
136 | static SCM | |
137 | alloc_future (SCM thunk) | |
138 | { | |
139 | scm_t_future *f = scm_gc_malloc (sizeof (*f), s_future); | |
140 | SCM future; | |
141 | f->data = SCM_BOOL_F; | |
142 | scm_mutex_init (&f->mutex, &scm_i_plugin_mutex); | |
143 | scm_cond_init (&f->cond, 0); | |
144 | f->die_p = 0; | |
145 | f->status = SCM_FUTURE_TASK_ASSIGNED; | |
146 | scm_mutex_lock (&future_admin_mutex); | |
147 | SCM_NEWSMOB2 (future, scm_tc16_future, futures, f); | |
148 | SCM_SET_FUTURE_DATA (future, thunk); | |
149 | futures = future; | |
150 | scm_mutex_unlock (&future_admin_mutex); | |
151 | scm_spawn_thread ((scm_t_catch_body) future_loop, | |
152 | SCM_FUTURE (future), | |
153 | (scm_t_catch_handler) future_handler, | |
154 | SCM_FUTURE (future)); | |
155 | return future; | |
156 | } | |
157 | ||
158 | static void | |
159 | kill_future (SCM future) | |
160 | { | |
161 | SCM_FUTURE (future)->die_p = 1; | |
162 | LINK (undead, future); | |
163 | } | |
164 | ||
165 | SCM | |
166 | scm_i_make_future (SCM thunk) | |
167 | { | |
168 | SCM future; | |
169 | scm_mutex_lock (&future_admin_mutex); | |
170 | while (1) | |
171 | { | |
d2e53ed6 | 172 | if (!scm_is_null (old)) |
6b468ba4 | 173 | UNLINK (old, future); |
d2e53ed6 | 174 | else if (!scm_is_null (young)) |
6b468ba4 MD |
175 | UNLINK (young, future); |
176 | else | |
177 | { | |
178 | scm_mutex_unlock (&future_admin_mutex); | |
179 | return alloc_future (thunk); | |
180 | } | |
181 | if (scm_mutex_trylock (SCM_FUTURE_MUTEX (future))) | |
182 | kill_future (future); | |
183 | else if (!SCM_FUTURE_ALIVE_P (future)) | |
184 | { | |
185 | scm_mutex_unlock (SCM_FUTURE_MUTEX (future)); | |
186 | cleanup (SCM_FUTURE (future)); | |
187 | } | |
188 | else | |
189 | break; | |
190 | } | |
191 | LINK (futures, future); | |
192 | scm_mutex_unlock (&future_admin_mutex); | |
193 | SCM_SET_FUTURE_DATA (future, thunk); | |
194 | SCM_SET_FUTURE_STATUS (future, SCM_FUTURE_TASK_ASSIGNED); | |
195 | scm_cond_signal (SCM_FUTURE_COND (future)); | |
196 | scm_mutex_unlock (SCM_FUTURE_MUTEX (future)); | |
197 | return future; | |
198 | } | |
199 | ||
200 | static SCM | |
201 | future_mark (SCM ptr) { | |
202 | return SCM_FUTURE_DATA (ptr); | |
203 | } | |
204 | ||
205 | static int | |
206 | future_print (SCM exp, SCM port, scm_print_state *pstate) | |
207 | { | |
208 | int writingp = SCM_WRITINGP (pstate); | |
209 | scm_puts ("#<future ", port); | |
210 | SCM_SET_WRITINGP (pstate, 1); | |
211 | scm_iprin1 (SCM_FUTURE_DATA (exp), port, pstate); | |
212 | SCM_SET_WRITINGP (pstate, writingp); | |
213 | scm_putc ('>', port); | |
214 | return !0; | |
215 | } | |
216 | ||
217 | SCM_DEFINE (scm_future_ref, "future-ref", 1, 0, 0, | |
218 | (SCM future), | |
219 | "If the future @var{x} has not been computed yet, compute and\n" | |
220 | "return @var{x}, otherwise just return the previously computed\n" | |
221 | "value.") | |
222 | #define FUNC_NAME s_scm_future_ref | |
223 | { | |
224 | SCM res; | |
225 | SCM_VALIDATE_FUTURE (1, future); | |
226 | scm_mutex_lock (SCM_FUTURE_MUTEX (future)); | |
227 | if (SCM_FUTURE_STATUS (future) != SCM_FUTURE_COMPUTING) | |
228 | { | |
229 | SCM_SET_FUTURE_STATUS (future, SCM_FUTURE_SIGNAL_ME); | |
230 | scm_cond_wait (SCM_FUTURE_COND (future), SCM_FUTURE_MUTEX (future)); | |
231 | } | |
232 | if (!SCM_FUTURE_ALIVE_P (future)) | |
233 | { | |
234 | scm_mutex_unlock (SCM_FUTURE_MUTEX (future)); | |
235 | SCM_MISC_ERROR ("requesting result from failed future ~A", | |
236 | scm_list_1 (future)); | |
237 | } | |
238 | res = SCM_FUTURE_DATA (future); | |
239 | scm_mutex_unlock (SCM_FUTURE_MUTEX (future)); | |
240 | return res; | |
241 | } | |
242 | #undef FUNC_NAME | |
243 | ||
244 | static void | |
245 | kill_futures (SCM victims) | |
246 | { | |
d2e53ed6 | 247 | while (!scm_is_null (victims)) |
6b468ba4 MD |
248 | { |
249 | SCM future; | |
250 | UNLINK (victims, future); | |
251 | kill_future (future); | |
252 | scm_cond_signal (SCM_FUTURE_COND (future)); | |
253 | } | |
254 | } | |
255 | ||
256 | static void | |
257 | cleanup_undead () | |
258 | { | |
259 | SCM next = undead, *nextloc = &undead; | |
d2e53ed6 | 260 | while (!scm_is_null (next)) |
6b468ba4 MD |
261 | { |
262 | if (scm_mutex_trylock (SCM_FUTURE_MUTEX (next))) | |
263 | goto next; | |
264 | else if (SCM_FUTURE_ALIVE_P (next)) | |
265 | { | |
266 | scm_cond_signal (SCM_FUTURE_COND (next)); | |
267 | scm_mutex_unlock (SCM_FUTURE_MUTEX (next)); | |
268 | next: | |
361d631f | 269 | SCM_SET_GC_MARK (next); |
6b468ba4 MD |
270 | nextloc = SCM_FUTURE_NEXTLOC (next); |
271 | next = *nextloc; | |
272 | } | |
273 | else | |
274 | { | |
275 | SCM future; | |
276 | UNLINK (next, future); | |
277 | scm_mutex_unlock (SCM_FUTURE_MUTEX (future)); | |
278 | cleanup (SCM_FUTURE (future)); | |
279 | *nextloc = next; | |
280 | } | |
281 | } | |
282 | } | |
283 | ||
284 | static void | |
285 | mark_futures (SCM futures) | |
286 | { | |
d2e53ed6 | 287 | while (!scm_is_null (futures)) |
6b468ba4 | 288 | { |
6b468ba4 MD |
289 | SCM_SET_GC_MARK (futures); |
290 | futures = SCM_FUTURE_NEXT (futures); | |
291 | } | |
292 | } | |
293 | ||
294 | static void * | |
295 | scan_futures (void *dummy1, void *dummy2, void *dummy3) | |
296 | { | |
297 | SCM next, *nextloc; | |
298 | ||
299 | long now = scm_c_get_internal_run_time (); | |
300 | if (now - last_switch > SCM_TIME_UNITS_PER_SECOND) | |
301 | { | |
302 | /* switch out old (> 1 sec), unused futures */ | |
303 | kill_futures (old); | |
304 | old = young; | |
305 | young = SCM_EOL; | |
306 | last_switch = now; | |
307 | } | |
361d631f MD |
308 | else |
309 | mark_futures (young); | |
6b468ba4 MD |
310 | |
311 | next = futures; | |
312 | nextloc = &futures; | |
d2e53ed6 | 313 | while (!scm_is_null (next)) |
6b468ba4 MD |
314 | { |
315 | if (!SCM_GC_MARK_P (next)) | |
316 | goto free; | |
317 | keep: | |
318 | nextloc = SCM_FUTURE_NEXTLOC (next); | |
319 | next = *nextloc; | |
320 | } | |
321 | goto exit; | |
d2e53ed6 | 322 | while (!scm_is_null (next)) |
6b468ba4 MD |
323 | { |
324 | if (SCM_GC_MARK_P (next)) | |
325 | { | |
326 | *nextloc = next; | |
327 | goto keep; | |
328 | } | |
329 | free: | |
330 | { | |
331 | SCM future; | |
332 | UNLINK (next, future); | |
361d631f | 333 | SCM_SET_GC_MARK (future); |
6b468ba4 MD |
334 | LINK (young, future); |
335 | } | |
336 | } | |
337 | *nextloc = SCM_EOL; | |
338 | exit: | |
339 | cleanup_undead (); | |
6b468ba4 | 340 | mark_futures (old); |
6b468ba4 MD |
341 | return 0; |
342 | } | |
343 | ||
344 | void | |
345 | scm_init_futures () | |
346 | { | |
347 | last_switch = scm_c_get_internal_run_time (); | |
348 | ||
349 | scm_loc_sys_thread_handler | |
350 | = SCM_VARIABLE_LOC (scm_c_define ("%thread-handler", SCM_BOOL_F)); | |
351 | ||
352 | scm_tc16_future = scm_make_smob_type ("future", 0); | |
353 | scm_set_smob_mark (scm_tc16_future, future_mark); | |
354 | scm_set_smob_print (scm_tc16_future, future_print); | |
355 | ||
356 | scm_c_hook_add (&scm_before_sweep_c_hook, scan_futures, 0, 0); | |
357 | #include "libguile/futures.x" | |
358 | } | |
359 | ||
360 | /* | |
361 | Local Variables: | |
362 | c-file-style: "gnu" | |
363 | End: | |
364 | */ |