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f2c9fcb0 | 1 | /* Copyright (C) 1995,1996,1997,1998, 1999, 2000 Free Software Foundation, Inc. |
0f2d19dd JB |
2 | * |
3 | * This program is free software; you can redistribute it and/or modify | |
4 | * it under the terms of the GNU General Public License as published by | |
5 | * the Free Software Foundation; either version 2, or (at your option) | |
6 | * any later version. | |
7 | * | |
8 | * This program 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 | |
11 | * GNU General Public License for more details. | |
12 | * | |
13 | * You should have received a copy of the GNU General Public License | |
14 | * along with this software; see the file COPYING. If not, write to | |
82892bed JB |
15 | * the Free Software Foundation, Inc., 59 Temple Place, Suite 330, |
16 | * Boston, MA 02111-1307 USA | |
0f2d19dd JB |
17 | * |
18 | * As a special exception, the Free Software Foundation gives permission | |
19 | * for additional uses of the text contained in its release of GUILE. | |
20 | * | |
21 | * The exception is that, if you link the GUILE library with other files | |
22 | * to produce an executable, this does not by itself cause the | |
23 | * resulting executable to be covered by the GNU General Public License. | |
24 | * Your use of that executable is in no way restricted on account of | |
25 | * linking the GUILE library code into it. | |
26 | * | |
27 | * This exception does not however invalidate any other reasons why | |
28 | * the executable file might be covered by the GNU General Public License. | |
29 | * | |
30 | * This exception applies only to the code released by the | |
31 | * Free Software Foundation under the name GUILE. If you copy | |
32 | * code from other Free Software Foundation releases into a copy of | |
33 | * GUILE, as the General Public License permits, the exception does | |
34 | * not apply to the code that you add in this way. To avoid misleading | |
35 | * anyone as to the status of such modified files, you must delete | |
36 | * this exception notice from them. | |
37 | * | |
38 | * If you write modifications of your own for GUILE, it is your choice | |
39 | * whether to permit this exception to apply to your modifications. | |
82892bed | 40 | * If you do not wish that, delete this exception notice. */ |
1bbd0b84 GB |
41 | |
42 | /* Software engineering face-lift by Greg J. Badros, 11-Dec-1999, | |
43 | gjb@cs.washington.edu, http://www.cs.washington.edu/homes/gjb */ | |
44 | ||
0f2d19dd JB |
45 | \f |
46 | ||
47 | #include <stdio.h> | |
a0599745 MD |
48 | #include "libguile/_scm.h" |
49 | #include "libguile/stackchk.h" | |
50 | #include "libguile/dynwind.h" | |
51 | #include "libguile/eval.h" | |
52 | #include "libguile/smob.h" | |
53 | #include "libguile/pairs.h" | |
54 | #include "libguile/throw.h" | |
55 | #include "libguile/fluids.h" | |
56 | #include "libguile/ports.h" | |
57 | ||
58 | #include "libguile/root.h" | |
0f2d19dd JB |
59 | \f |
60 | ||
e71575d9 MV |
61 | /* Define this if you want to try out the stack allocation of cwdr's |
62 | jumpbuf. It works for me but I'm still worried that the dynwinds | |
63 | might be able to make a mess. */ | |
64 | ||
65 | #undef USE_STACKJMPBUF | |
66 | ||
0f2d19dd | 67 | SCM scm_sys_protects[SCM_NUM_PROTECTS]; |
d564d753 MD |
68 | |
69 | long scm_tc16_root; | |
70 | ||
71 | #ifndef USE_THREADS | |
72 | struct scm_root_state *scm_root; | |
73 | #endif | |
0f2d19dd JB |
74 | |
75 | \f | |
76 | ||
d564d753 | 77 | static SCM |
1bbd0b84 | 78 | mark_root (SCM root) |
d564d753 MD |
79 | { |
80 | scm_root_state *s = SCM_ROOT_STATE (root); | |
dc53f026 | 81 | |
d564d753 MD |
82 | scm_gc_mark (s->rootcont); |
83 | scm_gc_mark (s->dynwinds); | |
84 | scm_gc_mark (s->continuation_stack); | |
85 | scm_gc_mark (s->continuation_stack_ptr); | |
86 | scm_gc_mark (s->progargs); | |
87 | scm_gc_mark (s->exitval); | |
88 | scm_gc_mark (s->cur_inp); | |
89 | scm_gc_mark (s->cur_outp); | |
90 | scm_gc_mark (s->cur_errp); | |
91 | scm_gc_mark (s->def_inp); | |
92 | scm_gc_mark (s->def_outp); | |
93 | scm_gc_mark (s->def_errp); | |
903073d5 | 94 | /* No need to gc mark def_loadp */ |
d9dfcf80 | 95 | scm_gc_mark (s->fluids); |
d564d753 MD |
96 | return SCM_ROOT_STATE (root) -> parent; |
97 | } | |
0f2d19dd | 98 | |
d564d753 | 99 | |
d564d753 | 100 | static int |
1bbd0b84 | 101 | print_root (SCM exp,SCM port,scm_print_state *pstate) |
d564d753 | 102 | { |
b7f3516f | 103 | scm_puts ("#<root ", port); |
d564d753 | 104 | scm_intprint(SCM_SEQ (SCM_ROOT_STATE (exp) -> rootcont), 16, port); |
b7f3516f | 105 | scm_putc('>', port); |
d564d753 MD |
106 | return 1; |
107 | } | |
108 | ||
d564d753 MD |
109 | |
110 | \f | |
111 | ||
112 | SCM | |
1bbd0b84 | 113 | scm_make_root (SCM parent) |
d564d753 MD |
114 | { |
115 | SCM root; | |
116 | scm_root_state *root_state; | |
117 | ||
118 | root_state = (scm_root_state *) scm_must_malloc (sizeof (scm_root_state), | |
119 | "scm_make_root"); | |
0c95b57d | 120 | if (SCM_ROOTP (parent)) |
d564d753 MD |
121 | { |
122 | memcpy (root_state, SCM_ROOT_STATE (parent), sizeof (scm_root_state)); | |
d9dfcf80 | 123 | scm_copy_fluids (root_state); |
d564d753 MD |
124 | root_state->parent = parent; |
125 | } | |
126 | else | |
127 | { | |
128 | root_state->parent = SCM_BOOL_F; | |
4ea1f83d JB |
129 | |
130 | /* Initialize everything right now, in case a GC happens early. */ | |
131 | root_state->rootcont | |
132 | = root_state->dynwinds | |
133 | = root_state->continuation_stack | |
134 | = root_state->continuation_stack_ptr | |
135 | = root_state->progargs | |
136 | = root_state->exitval | |
137 | = root_state->cur_inp | |
138 | = root_state->cur_outp | |
139 | = root_state->cur_errp | |
140 | = root_state->def_inp | |
141 | = root_state->def_outp | |
142 | = root_state->def_errp | |
143 | = root_state->cur_loadp | |
144 | = root_state->fluids | |
4ea1f83d JB |
145 | = root_state->handle |
146 | = root_state->parent | |
147 | = SCM_BOOL_F; | |
d564d753 | 148 | } |
d564d753 | 149 | SCM_REDEFER_INTS; |
23a62151 | 150 | SCM_NEWSMOB (root, scm_tc16_root, root_state); |
d564d753 MD |
151 | root_state->handle = root; |
152 | SCM_REALLOW_INTS; | |
153 | return root; | |
154 | } | |
155 | ||
1cc91f1b | 156 | /* {call-with-dynamic-root} |
d564d753 MD |
157 | * |
158 | * Suspending the current thread to evaluate a thunk on the | |
159 | * same C stack but under a new root. | |
160 | * | |
1cc91f1b | 161 | * Calls to call-with-dynamic-root return exactly once (unless |
e71575d9 | 162 | * the process is somehow exitted). */ |
d564d753 | 163 | |
650fa1ab JB |
164 | /* Some questions about cwdr: |
165 | ||
166 | Couldn't the body just be a closure? Do we really need to pass | |
167 | args through to it? | |
168 | ||
169 | The semantics are a lot like catch's; in fact, we call | |
170 | scm_internal_catch to take care of that part of things. Wouldn't | |
171 | it be cleaner to say that uncaught throws just disappear into the | |
172 | ether (or print a message to stderr), and let the caller use catch | |
173 | themselves if they want to? | |
174 | ||
175 | -JimB */ | |
176 | ||
d564d753 MD |
177 | #if 0 |
178 | SCM scm_exitval; /* INUM with return value */ | |
179 | #endif | |
180 | static int n_dynamic_roots = 0; | |
181 | ||
650fa1ab | 182 | |
e71575d9 MV |
183 | /* cwdr fills out both of these structures, and then passes a pointer |
184 | to them through scm_internal_catch to the cwdr_body and | |
185 | cwdr_handler functions, to tell them how to behave and to get | |
186 | information back from them. | |
650fa1ab JB |
187 | |
188 | A cwdr is a lot like a catch, except there is no tag (all | |
189 | exceptions are caught), and the body procedure takes the arguments | |
e71575d9 MV |
190 | passed to cwdr as A1 and ARGS. The handler is also special since |
191 | it is not directly run from scm_internal_catch. It is executed | |
192 | outside the new dynamic root. */ | |
650fa1ab JB |
193 | |
194 | struct cwdr_body_data { | |
650fa1ab JB |
195 | /* Arguments to pass to the cwdr body function. */ |
196 | SCM a1, args; | |
197 | ||
198 | /* Scheme procedure to use as body of cwdr. */ | |
199 | SCM body_proc; | |
e71575d9 MV |
200 | }; |
201 | ||
202 | struct cwdr_handler_data { | |
203 | /* Do we need to run the handler? */ | |
204 | int run_handler; | |
f032b8a8 | 205 | |
e71575d9 MV |
206 | /* The tag and args to pass it. */ |
207 | SCM tag, args; | |
650fa1ab JB |
208 | }; |
209 | ||
210 | ||
211 | /* Invoke the body of a cwdr, assuming that the throw handler has | |
212 | already been set up. DATA points to a struct set up by cwdr that | |
816a6f06 JB |
213 | says what proc to call, and what args to apply it to. |
214 | ||
215 | With a little thought, we could replace this with scm_body_thunk, | |
216 | but I don't want to mess with that at the moment. */ | |
650fa1ab | 217 | static SCM |
39752bec | 218 | cwdr_body (void *data) |
650fa1ab JB |
219 | { |
220 | struct cwdr_body_data *c = (struct cwdr_body_data *) data; | |
221 | ||
222 | return scm_apply (c->body_proc, c->a1, c->args); | |
223 | } | |
224 | ||
e71575d9 MV |
225 | /* Record the fact that the body of the cwdr has thrown. Record |
226 | enough information to invoke the handler later when the dynamic | |
227 | root has been deestablished. */ | |
650fa1ab | 228 | |
f032b8a8 | 229 | static SCM |
e71575d9 | 230 | cwdr_handler (void *data, SCM tag, SCM args) |
f032b8a8 | 231 | { |
e71575d9 | 232 | struct cwdr_handler_data *c = (struct cwdr_handler_data *) data; |
f032b8a8 | 233 | |
e71575d9 MV |
234 | c->run_handler = 1; |
235 | c->tag = tag; | |
236 | c->args = args; | |
237 | return SCM_UNSPECIFIED; | |
f032b8a8 | 238 | } |
d564d753 MD |
239 | |
240 | /* This is the basic code for new root creation. | |
241 | * | |
242 | * WARNING! The order of actions in this routine is in many ways | |
243 | * critical. E. g., it is essential that an error doesn't leave Guile | |
650fa1ab | 244 | * in a messed up state. */ |
d564d753 | 245 | |
e71575d9 MV |
246 | SCM |
247 | scm_internal_cwdr (scm_catch_body_t body, void *body_data, | |
248 | scm_catch_handler_t handler, void *handler_data, | |
249 | SCM_STACKITEM *stack_start) | |
d564d753 | 250 | { |
e71575d9 | 251 | #ifdef USE_STACKJMPBUF |
8b3bda20 | 252 | scm_contregs static_contregs; |
e71575d9 | 253 | #endif |
d564d753 | 254 | int old_ints_disabled = scm_ints_disabled; |
8938d022 | 255 | SCM old_rootcont, old_winds; |
e71575d9 | 256 | struct cwdr_handler_data my_handler_data; |
d564d753 MD |
257 | SCM answer; |
258 | ||
e71575d9 | 259 | /* Create a fresh root continuation. */ |
d564d753 MD |
260 | { |
261 | SCM new_rootcont; | |
262 | SCM_NEWCELL (new_rootcont); | |
263 | SCM_REDEFER_INTS; | |
e71575d9 | 264 | #ifdef USE_STACKJMPBUF |
8b3bda20 | 265 | SCM_SET_CONTREGS (new_rootcont, &static_contregs); |
e71575d9 | 266 | #else |
8b3bda20 DH |
267 | SCM_SET_CONTREGS (new_rootcont, |
268 | scm_must_malloc (sizeof (scm_contregs), | |
269 | "inferior root continuation")); | |
e71575d9 | 270 | #endif |
54778cd3 | 271 | SCM_SET_CELL_TYPE (new_rootcont, scm_tc7_contin); |
d564d753 MD |
272 | SCM_DYNENV (new_rootcont) = SCM_EOL; |
273 | SCM_BASE (new_rootcont) = stack_start; | |
8938d022 | 274 | SCM_SEQ (new_rootcont) = ++n_dynamic_roots; |
d564d753 MD |
275 | #ifdef DEBUG_EXTENSIONS |
276 | SCM_DFRAME (new_rootcont) = 0; | |
277 | #endif | |
8938d022 MD |
278 | old_rootcont = scm_rootcont; |
279 | scm_rootcont = new_rootcont; | |
d564d753 MD |
280 | SCM_REALLOW_INTS; |
281 | } | |
282 | ||
8938d022 MD |
283 | /* Exit caller's dynamic state. |
284 | */ | |
285 | old_winds = scm_dynwinds; | |
286 | scm_dowinds (SCM_EOL, scm_ilength (scm_dynwinds)); | |
d564d753 | 287 | #ifdef DEBUG_EXTENSIONS |
308277cb | 288 | SCM_DFRAME (old_rootcont) = scm_last_debug_frame; |
8938d022 | 289 | scm_last_debug_frame = 0; |
d564d753 | 290 | #endif |
650fa1ab | 291 | |
e71575d9 MV |
292 | { |
293 | my_handler_data.run_handler = 0; | |
816a6f06 | 294 | answer = scm_internal_catch (SCM_BOOL_T, |
e71575d9 MV |
295 | body, body_data, |
296 | cwdr_handler, &my_handler_data); | |
650fa1ab | 297 | } |
e71575d9 | 298 | |
d564d753 MD |
299 | scm_dowinds (old_winds, - scm_ilength (old_winds)); |
300 | SCM_REDEFER_INTS; | |
e71575d9 | 301 | #ifdef USE_STACKCJMPBUF |
8b3bda20 | 302 | SCM_SET_CONTREGS (scm_rootcont, NULL); |
e71575d9 | 303 | #endif |
d564d753 | 304 | #ifdef DEBUG_EXTENSIONS |
308277cb | 305 | scm_last_debug_frame = SCM_DFRAME (old_rootcont); |
d564d753 | 306 | #endif |
308277cb | 307 | scm_rootcont = old_rootcont; |
d564d753 MD |
308 | SCM_REALLOW_INTS; |
309 | scm_ints_disabled = old_ints_disabled; | |
e71575d9 MV |
310 | |
311 | /* Now run the real handler iff the body did a throw. */ | |
312 | if (my_handler_data.run_handler) | |
313 | return handler (handler_data, my_handler_data.tag, my_handler_data.args); | |
314 | else | |
315 | return answer; | |
d564d753 MD |
316 | } |
317 | ||
e71575d9 MV |
318 | /* The original CWDR for invoking Scheme code with a Scheme handler. */ |
319 | ||
320 | static SCM | |
321 | cwdr (SCM proc, SCM a1, SCM args, SCM handler, SCM_STACKITEM *stack_start) | |
322 | { | |
323 | struct cwdr_body_data c; | |
324 | ||
325 | c.a1 = a1; | |
326 | c.args = args; | |
327 | c.body_proc = proc; | |
328 | ||
329 | return scm_internal_cwdr (cwdr_body, &c, | |
330 | scm_handle_by_proc, &handler, | |
331 | stack_start); | |
332 | } | |
d564d753 | 333 | |
3b3b36dd | 334 | SCM_DEFINE (scm_call_with_dynamic_root, "call-with-dynamic-root", 2, 0, 0, |
1bbd0b84 | 335 | (SCM thunk, SCM handler), |
1bee0e70 | 336 | "Evaluate @code{(thunk)} in a new dynamic context, returning its value.\n\n" |
b380b885 MD |
337 | "If an error occurs during evaluation, apply @var{handler} to the\n" |
338 | "arguments to the throw, just as @code{throw} would. If this happens,\n" | |
339 | "@var{handler} is called outside the scope of the new root -- it is\n" | |
340 | "called in the same dynamic context in which\n" | |
341 | "@code{call-with-dynamic-root} was evaluated.\n\n" | |
342 | "If @var{thunk} captures a continuation, the continuation is rooted at\n" | |
343 | "the call to @var{thunk}. In particular, the call to\n" | |
344 | "@code{call-with-dynamic-root} is not captured. Therefore,\n" | |
345 | "@code{call-with-dynamic-root} always returns at most one time.\n\n" | |
346 | "Before calling @var{thunk}, the dynamic-wind chain is un-wound back to\n" | |
347 | "the root and a new chain started for @var{thunk}. Therefore, this call\n" | |
348 | "may not do what you expect:\n\n" | |
349 | "@example\n" | |
350 | ";; Almost certainly a bug:\n" | |
351 | "(with-output-to-port\n" | |
352 | " some-port\n\n" | |
353 | " (lambda ()\n" | |
354 | " (call-with-dynamic-root\n" | |
355 | " (lambda ()\n" | |
356 | " (display 'fnord)\n" | |
357 | " (newline))\n" | |
358 | " (lambda (errcode) errcode))))\n" | |
359 | "@end example\n\n" | |
2a2a730b | 360 | "The problem is, on what port will @samp{fnord} be displayed? You\n" |
b380b885 MD |
361 | "might expect that because of the @code{with-output-to-port} that\n" |
362 | "it will be displayed on the port bound to @code{some-port}. But it\n" | |
363 | "probably won't -- before evaluating the thunk, dynamic winds are\n" | |
364 | "unwound, including those created by @code{with-output-to-port}.\n" | |
365 | "So, the standard output port will have been re-set to its default value\n" | |
366 | "before @code{display} is evaluated.\n\n" | |
367 | "(This function was added to Guile mostly to help calls to functions in C\n" | |
368 | "libraries that can not tolerate non-local exits or calls that return\n" | |
369 | "multiple times. If such functions call back to the interpreter, it should\n" | |
370 | "be under a new dynamic root.)") | |
1bbd0b84 | 371 | #define FUNC_NAME s_scm_call_with_dynamic_root |
d564d753 MD |
372 | { |
373 | SCM_STACKITEM stack_place; | |
8938d022 | 374 | return cwdr (thunk, SCM_EOL, SCM_EOL, handler, &stack_place); |
d564d753 | 375 | } |
1bbd0b84 | 376 | #undef FUNC_NAME |
d564d753 | 377 | |
3b3b36dd | 378 | SCM_DEFINE (scm_dynamic_root, "dynamic-root", 0, 0, 0, |
1bbd0b84 | 379 | (), |
b380b885 MD |
380 | "Return an object representing the current dynamic root.\n\n" |
381 | "These objects are only useful for comparison using @code{eq?}.\n" | |
382 | "They are currently represented as numbers, but your code should\n" | |
383 | "in no way depend on this.") | |
1bbd0b84 | 384 | #define FUNC_NAME s_scm_dynamic_root |
d564d753 MD |
385 | { |
386 | return scm_ulong2num (SCM_SEQ (scm_root->rootcont)); | |
387 | } | |
1bbd0b84 | 388 | #undef FUNC_NAME |
d564d753 | 389 | |
d564d753 | 390 | SCM |
1bbd0b84 | 391 | scm_apply_with_dynamic_root (SCM proc, SCM a1, SCM args, SCM handler) |
d564d753 MD |
392 | { |
393 | SCM_STACKITEM stack_place; | |
8938d022 | 394 | return cwdr (proc, a1, args, handler, &stack_place); |
d564d753 | 395 | } |
0f2d19dd JB |
396 | |
397 | \f | |
398 | ||
cc4feeca DH |
399 | #if (SCM_DEBUG_DEPRECATED == 0) |
400 | ||
0f2d19dd JB |
401 | /* Call thunk(closure) underneath a top-level error handler. |
402 | * If an error occurs, pass the exitval through err_filter and return it. | |
403 | * If no error occurs, return the value of thunk. | |
404 | */ | |
405 | ||
0f2d19dd JB |
406 | #ifdef _UNICOS |
407 | typedef int setjmp_type; | |
408 | #else | |
409 | typedef long setjmp_type; | |
410 | #endif | |
411 | ||
412 | ||
0f2d19dd | 413 | SCM |
1bbd0b84 | 414 | scm_call_catching_errors (SCM (*thunk)(), SCM (*err_filter)(), void *closure) |
0f2d19dd JB |
415 | { |
416 | SCM answer; | |
417 | setjmp_type i; | |
faa6b3df | 418 | #ifdef DEBUG_EXTENSIONS |
8938d022 | 419 | SCM_DFRAME (scm_rootcont) = scm_last_debug_frame; |
faa6b3df | 420 | #endif |
0f2d19dd | 421 | i = setjmp (SCM_JMPBUF (scm_rootcont)); |
faa6b3df | 422 | scm_stack_checking_enabled_p = SCM_STACK_CHECKING_P; |
0f2d19dd JB |
423 | if (!i) |
424 | { | |
425 | scm_gc_heap_lock = 0; | |
426 | answer = thunk (closure); | |
427 | } | |
428 | else | |
429 | { | |
430 | scm_gc_heap_lock = 1; | |
431 | answer = err_filter (scm_exitval, closure); | |
432 | } | |
433 | return answer; | |
434 | } | |
435 | ||
cc4feeca DH |
436 | #endif /* SCM_DEBUG_DEPRECATED == 0 */ |
437 | ||
438 | ||
d564d753 MD |
439 | void |
440 | scm_init_root () | |
441 | { | |
cc4feeca DH |
442 | scm_tc16_root = scm_make_smob_type ("root", sizeof (struct scm_root_state)); |
443 | scm_set_smob_mark (scm_tc16_root, mark_root); | |
444 | scm_set_smob_print (scm_tc16_root, print_root); | |
445 | ||
8dc9439f | 446 | #ifndef SCM_MAGIC_SNARFER |
a0599745 | 447 | #include "libguile/root.x" |
8dc9439f | 448 | #endif |
d564d753 | 449 | } |
89e00824 ML |
450 | |
451 | /* | |
452 | Local Variables: | |
453 | c-file-style: "gnu" | |
454 | End: | |
455 | */ |