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44b76a78 | 1 | /* Copyright (C) 1995,1996,1997,1998,2000,2001, 2002, 2004, 2006, 2008, 2009, 2010, 2011 Free Software Foundation, Inc. |
843e4e9d | 2 | * |
73be1d9e | 3 | * This library is free software; you can redistribute it and/or |
53befeb7 NJ |
4 | * modify it under the terms of the GNU Lesser General Public License |
5 | * as published by the Free Software Foundation; either version 3 of | |
6 | * the License, or (at your option) any later version. | |
843e4e9d | 7 | * |
53befeb7 NJ |
8 | * This library is distributed in the hope that it will be useful, but |
9 | * WITHOUT ANY WARRANTY; without even the implied warranty of | |
73be1d9e MV |
10 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
11 | * Lesser General Public License for more details. | |
843e4e9d | 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 | |
53befeb7 NJ |
15 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA |
16 | * 02110-1301 USA | |
73be1d9e | 17 | */ |
1bbd0b84 | 18 | |
1bbd0b84 | 19 | |
0f2d19dd | 20 | \f |
dbb605f5 | 21 | #ifdef HAVE_CONFIG_H |
ef92a2a2 RB |
22 | # include <config.h> |
23 | #endif | |
0f2d19dd | 24 | |
a0599745 MD |
25 | #include "libguile/_scm.h" |
26 | #include "libguile/eval.h" | |
27 | #include "libguile/throw.h" | |
28 | #include "libguile/root.h" | |
29 | #include "libguile/smob.h" | |
e292f7aa | 30 | #include "libguile/dynwind.h" |
2d3179db | 31 | #include "libguile/deprecation.h" |
20e6290e | 32 | |
a0599745 MD |
33 | #include "libguile/validate.h" |
34 | #include "libguile/async.h" | |
0f2d19dd | 35 | |
95b88819 GH |
36 | #ifdef HAVE_STRING_H |
37 | #include <string.h> | |
38 | #endif | |
0f2d19dd JB |
39 | #ifdef HAVE_UNISTD_H |
40 | #include <unistd.h> | |
41 | #endif | |
42 | ||
634aa8de LC |
43 | #include <full-write.h> |
44 | ||
0f2d19dd JB |
45 | \f |
46 | /* {Asynchronous Events} | |
47 | * | |
2d3179db MV |
48 | * There are two kinds of asyncs: system asyncs and user asyncs. The |
49 | * two kinds have some concepts in commen but work slightly | |
50 | * differently and are not interchangeable. | |
0f2d19dd | 51 | * |
2d3179db MV |
52 | * System asyncs are used to run arbitrary code at the next safe point |
53 | * in a specified thread. You can use them to trigger execution of | |
54 | * Scheme code from signal handlers or to interrupt a thread, for | |
55 | * example. | |
0f2d19dd | 56 | * |
2d3179db MV |
57 | * Each thread has a list of 'activated asyncs', which is a normal |
58 | * Scheme list of procedures with zero arguments. When a thread | |
59 | * executes a SCM_ASYNC_TICK statement (which is included in | |
60 | * SCM_TICK), it will call all procedures on this list. | |
843e4e9d | 61 | * |
2d3179db MV |
62 | * Also, a thread will wake up when a procedure is added to its list |
63 | * of active asyncs and call them. After that, it will go to sleep | |
64 | * again. (Not implemented yet.) | |
0f2d19dd | 65 | * |
0f2d19dd | 66 | * |
2d3179db MV |
67 | * User asyncs are a little data structure that consists of a |
68 | * procedure of zero arguments and a mark. There are functions for | |
69 | * setting the mark of a user async and for calling all procedures of | |
70 | * marked asyncs in a given list. Nothing you couldn't quickly | |
71 | * implement yourself. | |
0f2d19dd JB |
72 | */ |
73 | ||
0f2d19dd | 74 | |
2d3179db | 75 | \f |
0f2d19dd | 76 | |
2d3179db | 77 | /* User asyncs. */ |
e94e3f21 | 78 | |
2d3179db | 79 | static scm_t_bits tc16_async; |
e94e3f21 ML |
80 | |
81 | /* cmm: this has SCM_ prefix because SCM_MAKE_VALIDATE expects it. | |
82 | this is ugly. */ | |
e841c3e0 | 83 | #define SCM_ASYNCP(X) SCM_TYP16_PREDICATE (tc16_async, X) |
6182ceac | 84 | #define VALIDATE_ASYNC(pos, a) SCM_MAKE_VALIDATE_MSG(pos, a, ASYNCP, "user async") |
e94e3f21 | 85 | |
e779fef7 AW |
86 | #define ASYNC_GOT_IT(X) (SCM_SMOB_FLAGS (X)) |
87 | #define SET_ASYNC_GOT_IT(X, V) (SCM_SET_SMOB_FLAGS ((X), ((V)))) | |
88 | #define ASYNC_THUNK(X) SCM_SMOB_OBJECT_1 (X) | |
0f2d19dd | 89 | |
0f2d19dd | 90 | |
843e4e9d | 91 | SCM_DEFINE (scm_async, "async", 1, 0, 0, |
811cf846 MG |
92 | (SCM thunk), |
93 | "Create a new async for the procedure @var{thunk}.") | |
1bbd0b84 | 94 | #define FUNC_NAME s_scm_async |
0f2d19dd | 95 | { |
e94e3f21 | 96 | SCM_RETURN_NEWSMOB (tc16_async, SCM_UNPACK (thunk)); |
0f2d19dd | 97 | } |
1bbd0b84 | 98 | #undef FUNC_NAME |
0f2d19dd | 99 | |
843e4e9d | 100 | SCM_DEFINE (scm_async_mark, "async-mark", 1, 0, 0, |
1bbd0b84 | 101 | (SCM a), |
811cf846 | 102 | "Mark the async @var{a} for future execution.") |
1bbd0b84 | 103 | #define FUNC_NAME s_scm_async_mark |
0f2d19dd | 104 | { |
e94e3f21 | 105 | VALIDATE_ASYNC (1, a); |
e94e3f21 | 106 | SET_ASYNC_GOT_IT (a, 1); |
0f2d19dd JB |
107 | return SCM_UNSPECIFIED; |
108 | } | |
1bbd0b84 | 109 | #undef FUNC_NAME |
0f2d19dd | 110 | |
843e4e9d | 111 | SCM_DEFINE (scm_run_asyncs, "run-asyncs", 1, 0, 0, |
811cf846 MG |
112 | (SCM list_of_a), |
113 | "Execute all thunks from the asyncs of the list @var{list_of_a}.") | |
1bbd0b84 | 114 | #define FUNC_NAME s_scm_run_asyncs |
0f2d19dd | 115 | { |
c96d76b8 | 116 | while (! SCM_NULL_OR_NIL_P (list_of_a)) |
0f2d19dd JB |
117 | { |
118 | SCM a; | |
9f0e55a6 | 119 | SCM_VALIDATE_CONS (1, list_of_a); |
1bbd0b84 | 120 | a = SCM_CAR (list_of_a); |
e94e3f21 | 121 | VALIDATE_ASYNC (SCM_ARG1, a); |
e94e3f21 | 122 | if (ASYNC_GOT_IT (a)) |
0f2d19dd | 123 | { |
e94e3f21 | 124 | SET_ASYNC_GOT_IT (a, 0); |
fdc28395 | 125 | scm_call_0 (ASYNC_THUNK (a)); |
0f2d19dd | 126 | } |
1bbd0b84 | 127 | list_of_a = SCM_CDR (list_of_a); |
0f2d19dd JB |
128 | } |
129 | return SCM_BOOL_T; | |
130 | } | |
1bbd0b84 | 131 | #undef FUNC_NAME |
0f2d19dd JB |
132 | |
133 | \f | |
134 | ||
9de87eea MV |
135 | static scm_i_pthread_mutex_t async_mutex = SCM_I_PTHREAD_MUTEX_INITIALIZER; |
136 | ||
2d3179db | 137 | /* System asyncs. */ |
0f2d19dd | 138 | |
2d3179db | 139 | void |
27c6ebcb | 140 | scm_async_tick (void) |
0f2d19dd | 141 | { |
9de87eea MV |
142 | scm_i_thread *t = SCM_I_CURRENT_THREAD; |
143 | SCM asyncs; | |
144 | ||
402858a4 | 145 | /* Reset pending_asyncs even when asyncs are blocked and not really |
9de87eea MV |
146 | executed since this will avoid future futile calls to this |
147 | function. When asyncs are unblocked again, this function is | |
148 | invoked even when pending_asyncs is zero. | |
402858a4 | 149 | */ |
2d3179db | 150 | |
9de87eea MV |
151 | scm_i_scm_pthread_mutex_lock (&async_mutex); |
152 | t->pending_asyncs = 0; | |
153 | if (t->block_asyncs == 0) | |
2d3179db | 154 | { |
9de87eea MV |
155 | asyncs = t->active_asyncs; |
156 | t->active_asyncs = SCM_EOL; | |
157 | } | |
158 | else | |
159 | asyncs = SCM_EOL; | |
160 | scm_i_pthread_mutex_unlock (&async_mutex); | |
161 | ||
162 | while (scm_is_pair (asyncs)) | |
163 | { | |
164 | SCM next = SCM_CDR (asyncs); | |
165 | SCM_SETCDR (asyncs, SCM_BOOL_F); | |
166 | scm_call_0 (SCM_CAR (asyncs)); | |
167 | asyncs = next; | |
2d3179db | 168 | } |
0f2d19dd JB |
169 | } |
170 | ||
2d3179db | 171 | void |
9de87eea | 172 | scm_i_queue_async_cell (SCM c, scm_i_thread *t) |
2d3179db | 173 | { |
9de87eea MV |
174 | SCM sleep_object; |
175 | scm_i_pthread_mutex_t *sleep_mutex; | |
176 | int sleep_fd; | |
177 | SCM p; | |
178 | ||
179 | scm_i_scm_pthread_mutex_lock (&async_mutex); | |
180 | p = t->active_asyncs; | |
402858a4 | 181 | SCM_SETCDR (c, SCM_EOL); |
9de87eea MV |
182 | if (!scm_is_pair (p)) |
183 | t->active_asyncs = c; | |
402858a4 | 184 | else |
2d3179db | 185 | { |
402858a4 | 186 | SCM pp; |
9de87eea | 187 | while (scm_is_pair (pp = SCM_CDR (p))) |
f6b44bd9 | 188 | { |
9de87eea MV |
189 | if (scm_is_eq (SCM_CAR (p), SCM_CAR (c))) |
190 | { | |
191 | scm_i_pthread_mutex_unlock (&async_mutex); | |
192 | return; | |
193 | } | |
402858a4 | 194 | p = pp; |
f6b44bd9 | 195 | } |
402858a4 | 196 | SCM_SETCDR (p, c); |
2d3179db | 197 | } |
9de87eea MV |
198 | t->pending_asyncs = 1; |
199 | sleep_object = t->sleep_object; | |
200 | sleep_mutex = t->sleep_mutex; | |
201 | sleep_fd = t->sleep_fd; | |
202 | scm_i_pthread_mutex_unlock (&async_mutex); | |
203 | ||
204 | if (sleep_mutex) | |
205 | { | |
206 | /* By now, the thread T might be out of its sleep already, or | |
207 | might even be in the next, unrelated sleep. Interrupting it | |
208 | anyway does no harm, however. | |
209 | ||
210 | The important thing to prevent here is to signal sleep_cond | |
211 | before T waits on it. This can not happen since T has | |
212 | sleep_mutex locked while setting t->sleep_mutex and will only | |
213 | unlock it again while waiting on sleep_cond. | |
214 | */ | |
215 | scm_i_scm_pthread_mutex_lock (sleep_mutex); | |
216 | scm_i_pthread_cond_signal (&t->sleep_cond); | |
217 | scm_i_pthread_mutex_unlock (sleep_mutex); | |
218 | } | |
219 | ||
220 | if (sleep_fd >= 0) | |
221 | { | |
222 | char dummy = 0; | |
634aa8de | 223 | |
9de87eea MV |
224 | /* Likewise, T might already been done with sleeping here, but |
225 | interrupting it once too often does no harm. T might also | |
226 | not yet have started sleeping, but this is no problem either | |
227 | since the data written to a pipe will not be lost, unlike a | |
634aa8de LC |
228 | condition variable signal. */ |
229 | full_write (sleep_fd, &dummy, 1); | |
9de87eea MV |
230 | } |
231 | ||
232 | /* This is needed to protect sleep_mutex. | |
233 | */ | |
234 | scm_remember_upto_here_1 (sleep_object); | |
235 | } | |
236 | ||
237 | int | |
238 | scm_i_setup_sleep (scm_i_thread *t, | |
239 | SCM sleep_object, scm_i_pthread_mutex_t *sleep_mutex, | |
240 | int sleep_fd) | |
241 | { | |
242 | int pending; | |
243 | ||
244 | scm_i_scm_pthread_mutex_lock (&async_mutex); | |
245 | pending = t->pending_asyncs; | |
246 | if (!pending) | |
247 | { | |
248 | t->sleep_object = sleep_object; | |
249 | t->sleep_mutex = sleep_mutex; | |
250 | t->sleep_fd = sleep_fd; | |
251 | } | |
252 | scm_i_pthread_mutex_unlock (&async_mutex); | |
253 | return pending; | |
254 | } | |
255 | ||
256 | void | |
257 | scm_i_reset_sleep (scm_i_thread *t) | |
258 | { | |
259 | scm_i_scm_pthread_mutex_lock (&async_mutex); | |
260 | t->sleep_object = SCM_BOOL_F; | |
261 | t->sleep_mutex = NULL; | |
262 | t->sleep_fd = -1; | |
263 | scm_i_pthread_mutex_unlock (&async_mutex); | |
2d3179db | 264 | } |
0f2d19dd | 265 | |
2d3179db MV |
266 | SCM_DEFINE (scm_system_async_mark_for_thread, "system-async-mark", 1, 1, 0, |
267 | (SCM proc, SCM thread), | |
0a50eeaa NJ |
268 | "Mark @var{proc} (a procedure with zero arguments) for future execution\n" |
269 | "in @var{thread}. If @var{proc} has already been marked for\n" | |
270 | "@var{thread} but has not been executed yet, this call has no effect.\n" | |
271 | "If @var{thread} is omitted, the thread that called\n" | |
272 | "@code{system-async-mark} is used.\n\n" | |
273 | "This procedure is not safe to be called from C signal handlers. Use\n" | |
274 | "@code{scm_sigaction} or @code{scm_sigaction_for_thread} to install\n" | |
275 | "signal handlers.") | |
2d3179db MV |
276 | #define FUNC_NAME s_scm_system_async_mark_for_thread |
277 | { | |
9de87eea MV |
278 | /* The current thread might not have a handle yet. This can happen |
279 | when the GC runs immediately before allocating the handle. At | |
280 | the end of that GC, a system async might be marked. Thus, we can | |
281 | not use scm_current_thread here. | |
282 | */ | |
283 | ||
284 | scm_i_thread *t; | |
285 | ||
028e573c | 286 | if (SCM_UNBNDP (thread)) |
9de87eea | 287 | t = SCM_I_CURRENT_THREAD; |
028e573c | 288 | else |
402858a4 MV |
289 | { |
290 | SCM_VALIDATE_THREAD (2, thread); | |
291 | if (scm_c_thread_exited_p (thread)) | |
292 | SCM_MISC_ERROR ("thread has already exited", SCM_EOL); | |
9de87eea | 293 | t = SCM_I_THREAD_DATA (thread); |
402858a4 | 294 | } |
9de87eea | 295 | scm_i_queue_async_cell (scm_cons (proc, SCM_BOOL_F), t); |
2d3179db MV |
296 | return SCM_UNSPECIFIED; |
297 | } | |
298 | #undef FUNC_NAME | |
9f0e55a6 | 299 | |
2d3179db MV |
300 | SCM |
301 | scm_system_async_mark (SCM proc) | |
302 | #define FUNC_NAME s_scm_system_async_mark_for_thread | |
0f2d19dd | 303 | { |
2d3179db | 304 | return scm_system_async_mark_for_thread (proc, SCM_UNDEFINED); |
0f2d19dd | 305 | } |
1bbd0b84 | 306 | #undef FUNC_NAME |
0f2d19dd JB |
307 | |
308 | \f | |
309 | ||
310 | ||
2d3179db MV |
311 | SCM_DEFINE (scm_noop, "noop", 0, 0, 1, |
312 | (SCM args), | |
313 | "Do nothing. When called without arguments, return @code{#f},\n" | |
314 | "otherwise return the first argument.") | |
315 | #define FUNC_NAME s_scm_noop | |
0f2d19dd | 316 | { |
2d3179db MV |
317 | SCM_VALIDATE_REST_ARGUMENT (args); |
318 | return (SCM_NULL_OR_NIL_P (args) ? SCM_BOOL_F : SCM_CAR (args)); | |
0f2d19dd | 319 | } |
1bbd0b84 | 320 | #undef FUNC_NAME |
0f2d19dd | 321 | |
0f2d19dd | 322 | |
0f2d19dd JB |
323 | \f |
324 | ||
e292f7aa | 325 | static void |
9de87eea | 326 | increase_block (void *data) |
e292f7aa | 327 | { |
c98ce8f5 AW |
328 | scm_i_thread *t = data; |
329 | t->block_asyncs++; | |
e292f7aa MV |
330 | } |
331 | ||
332 | static void | |
9de87eea | 333 | decrease_block (void *data) |
e292f7aa | 334 | { |
c98ce8f5 AW |
335 | scm_i_thread *t = data; |
336 | if (--t->block_asyncs == 0) | |
27c6ebcb | 337 | scm_async_tick (); |
e292f7aa MV |
338 | } |
339 | ||
c98ce8f5 AW |
340 | void |
341 | scm_dynwind_block_asyncs (void) | |
342 | { | |
343 | scm_i_thread *t = SCM_I_CURRENT_THREAD; | |
344 | scm_dynwind_rewind_handler (increase_block, t, SCM_F_WIND_EXPLICITLY); | |
345 | scm_dynwind_unwind_handler (decrease_block, t, SCM_F_WIND_EXPLICITLY); | |
346 | } | |
347 | ||
348 | void | |
349 | scm_dynwind_unblock_asyncs (void) | |
350 | { | |
351 | scm_i_thread *t = SCM_I_CURRENT_THREAD; | |
352 | if (t->block_asyncs == 0) | |
353 | scm_misc_error ("scm_with_unblocked_asyncs", | |
354 | "asyncs already unblocked", SCM_EOL); | |
355 | scm_dynwind_rewind_handler (decrease_block, t, SCM_F_WIND_EXPLICITLY); | |
356 | scm_dynwind_unwind_handler (increase_block, t, SCM_F_WIND_EXPLICITLY); | |
357 | } | |
358 | ||
e292f7aa MV |
359 | SCM_DEFINE (scm_call_with_blocked_asyncs, "call-with-blocked-asyncs", 1, 0, 0, |
360 | (SCM proc), | |
361 | "Call @var{proc} with no arguments and block the execution\n" | |
362 | "of system asyncs by one level for the current thread while\n" | |
363 | "it is running. Return the value returned by @var{proc}.\n") | |
364 | #define FUNC_NAME s_scm_call_with_blocked_asyncs | |
365 | { | |
c98ce8f5 AW |
366 | SCM ans; |
367 | ||
368 | scm_dynwind_begin (SCM_F_DYNWIND_REWINDABLE); | |
369 | scm_dynwind_block_asyncs (); | |
370 | ans = scm_call_0 (proc); | |
371 | scm_dynwind_end (); | |
372 | ||
373 | return ans; | |
e292f7aa MV |
374 | } |
375 | #undef FUNC_NAME | |
376 | ||
377 | void * | |
378 | scm_c_call_with_blocked_asyncs (void *(*proc) (void *data), void *data) | |
379 | { | |
c98ce8f5 AW |
380 | void* ans; |
381 | ||
382 | scm_dynwind_begin (SCM_F_DYNWIND_REWINDABLE); | |
383 | scm_dynwind_block_asyncs (); | |
384 | ans = proc (data); | |
385 | scm_dynwind_end (); | |
386 | ||
387 | return ans; | |
e292f7aa MV |
388 | } |
389 | ||
390 | ||
391 | SCM_DEFINE (scm_call_with_unblocked_asyncs, "call-with-unblocked-asyncs", 1, 0, 0, | |
392 | (SCM proc), | |
393 | "Call @var{proc} with no arguments and unblock the execution\n" | |
394 | "of system asyncs by one level for the current thread while\n" | |
395 | "it is running. Return the value returned by @var{proc}.\n") | |
396 | #define FUNC_NAME s_scm_call_with_unblocked_asyncs | |
397 | { | |
c98ce8f5 AW |
398 | SCM ans; |
399 | ||
9de87eea | 400 | if (SCM_I_CURRENT_THREAD->block_asyncs == 0) |
e292f7aa | 401 | SCM_MISC_ERROR ("asyncs already unblocked", SCM_EOL); |
c98ce8f5 AW |
402 | |
403 | scm_dynwind_begin (SCM_F_DYNWIND_REWINDABLE); | |
404 | scm_dynwind_unblock_asyncs (); | |
405 | ans = scm_call_0 (proc); | |
406 | scm_dynwind_end (); | |
407 | ||
408 | return ans; | |
e292f7aa MV |
409 | } |
410 | #undef FUNC_NAME | |
411 | ||
412 | void * | |
413 | scm_c_call_with_unblocked_asyncs (void *(*proc) (void *data), void *data) | |
414 | { | |
c98ce8f5 AW |
415 | void* ans; |
416 | ||
9de87eea | 417 | if (SCM_I_CURRENT_THREAD->block_asyncs == 0) |
e292f7aa MV |
418 | scm_misc_error ("scm_c_call_with_unblocked_asyncs", |
419 | "asyncs already unblocked", SCM_EOL); | |
e292f7aa | 420 | |
c98ce8f5 AW |
421 | scm_dynwind_begin (SCM_F_DYNWIND_REWINDABLE); |
422 | scm_dynwind_unblock_asyncs (); | |
423 | ans = proc (data); | |
424 | scm_dynwind_end (); | |
b57a0953 | 425 | |
c98ce8f5 | 426 | return ans; |
b57a0953 MV |
427 | } |
428 | ||
46935a1f LC |
429 | \f |
430 | /* These are function variants of the same-named macros (uppercase) for use | |
431 | outside of libguile. This is so that `SCM_I_CURRENT_THREAD', which may | |
432 | reside in TLS, is not accessed from outside of libguile. It thus allows | |
433 | libguile to be built with the "local-dynamic" TLS model. */ | |
434 | ||
435 | void | |
436 | scm_critical_section_start (void) | |
437 | { | |
438 | SCM_CRITICAL_SECTION_START; | |
439 | } | |
440 | ||
441 | void | |
442 | scm_critical_section_end (void) | |
443 | { | |
444 | SCM_CRITICAL_SECTION_END; | |
445 | } | |
446 | ||
0f2d19dd JB |
447 | \f |
448 | ||
0f2d19dd JB |
449 | void |
450 | scm_init_async () | |
0f2d19dd | 451 | { |
73ea78af | 452 | tc16_async = scm_make_smob_type ("async", 0); |
73ea78af | 453 | |
a0599745 | 454 | #include "libguile/async.x" |
0f2d19dd | 455 | } |
89e00824 ML |
456 | |
457 | /* | |
458 | Local Variables: | |
459 | c-file-style: "gnu" | |
460 | End: | |
461 | */ |