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1 | /* Copyright (C) 1995,1996 Free Software Foundation, Inc. |
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 | |
15 | * the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. | |
16 | * | |
17 | * As a special exception, the Free Software Foundation gives permission | |
18 | * for additional uses of the text contained in its release of GUILE. | |
19 | * | |
20 | * The exception is that, if you link the GUILE library with other files | |
21 | * to produce an executable, this does not by itself cause the | |
22 | * resulting executable to be covered by the GNU General Public License. | |
23 | * Your use of that executable is in no way restricted on account of | |
24 | * linking the GUILE library code into it. | |
25 | * | |
26 | * This exception does not however invalidate any other reasons why | |
27 | * the executable file might be covered by the GNU General Public License. | |
28 | * | |
29 | * This exception applies only to the code released by the | |
30 | * Free Software Foundation under the name GUILE. If you copy | |
31 | * code from other Free Software Foundation releases into a copy of | |
32 | * GUILE, as the General Public License permits, the exception does | |
33 | * not apply to the code that you add in this way. To avoid misleading | |
34 | * anyone as to the status of such modified files, you must delete | |
35 | * this exception notice from them. | |
36 | * | |
37 | * If you write modifications of your own for GUILE, it is your choice | |
38 | * whether to permit this exception to apply to your modifications. | |
39 | * If you do not wish that, delete this exception notice. | |
40 | */ | |
41 | \f | |
42 | ||
43 | #include <stdio.h> | |
44 | #include "_scm.h" | |
45 | ||
46 | \f | |
47 | ||
48 | ||
49 | /* {Catch and Throw} | |
50 | */ | |
51 | static int scm_tc16_jmpbuffer; | |
52 | ||
53 | SCM scm_bad_throw_vcell; | |
54 | ||
55 | #define SCM_JMPBUFP(O) (SCM_TYP16(O) == scm_tc16_jmpbuffer) | |
56 | #define JBACTIVE(O) (SCM_CAR (O) & (1L << 16L)) | |
57 | #define ACTIVATEJB(O) (SCM_CAR (O) |= (1L << 16L)) | |
58 | #define DEACTIVATEJB(O) (SCM_CAR (O) &= ~(1L << 16L)) | |
59 | ||
60 | #ifdef DEBUG_EXTENSIONS | |
61 | #define JBSCM_DFRAME(O) ((debug_frame*)SCM_CAR (SCM_CDR (O)) ) | |
62 | #define JBJMPBUF(O) ((jmp_buf*)SCM_CDR (SCM_CDR (O)) ) | |
63 | #define SETJBSCM_DFRAME(O,X) SCM_CAR(SCM_CDR (O)) = (SCM)(X) | |
64 | #define SETJBJMPBUF(O,X) SCM_SETCDR(SCM_CDR (O), X) | |
65 | #else | |
66 | #define JBJMPBUF(O) ((jmp_buf*)SCM_CDR (O) ) | |
67 | #define SETJBJMPBUF SCM_SETCDR | |
68 | #endif | |
69 | ||
70 | #ifdef __STDC__ | |
71 | static int | |
72 | printjb (SCM exp, SCM port, int writing) | |
73 | #else | |
74 | static int | |
75 | printjb (exp, port, writing) | |
76 | SCM exp; | |
77 | SCM port; | |
78 | int writing; | |
79 | #endif | |
80 | { | |
81 | scm_gen_puts (scm_regular_string, "#<jmpbuffer ", port); | |
82 | scm_gen_puts (scm_regular_string, JBACTIVE(exp) ? "(active) " : "(inactive) ", port); | |
83 | scm_intprint((SCM) JBJMPBUF(exp), 16, port); | |
84 | scm_gen_putc ('>', port); | |
85 | return 1 ; | |
86 | } | |
87 | ||
88 | /* !!! The mark function needs to be different for | |
89 | * debugging support. A. Green | |
90 | */ | |
91 | static scm_smobfuns jbsmob = {scm_mark0, scm_free0, printjb, 0}; | |
92 | ||
93 | #ifdef __STDC__ | |
94 | static SCM | |
95 | make_jmpbuf (void) | |
96 | #else | |
97 | static SCM | |
98 | make_jmpbuf () | |
99 | #endif | |
100 | { | |
101 | SCM answer; | |
102 | SCM_NEWCELL (answer); | |
103 | #ifdef DEBUG_EXTENSIONS | |
104 | SCM_NEWCELL (SCM_CDR (answer)); | |
105 | #endif | |
106 | SCM_DEFER_INTS; | |
107 | { | |
108 | SCM_CAR(answer) = scm_tc16_jmpbuffer; | |
109 | SETJBJMPBUF(answer, (jmp_buf *)0); | |
110 | DEACTIVATEJB(answer); | |
111 | } | |
112 | SCM_ALLOW_INTS; | |
113 | return answer; | |
114 | } | |
115 | ||
116 | ||
117 | struct jmp_buf_and_retval /* use only on the stack, in scm_catch */ | |
118 | { | |
119 | jmp_buf buf; /* must be first */ | |
120 | SCM throw_tag; | |
121 | SCM retval; | |
122 | }; | |
123 | ||
124 | SCM_PROC(s_catch, "catch", 3, 0, 0, scm_catch); | |
125 | #ifdef __STDC__ | |
126 | SCM | |
127 | scm_catch (SCM tag, SCM thunk, SCM handler) | |
128 | #else | |
129 | SCM | |
130 | scm_catch (tag, thunk, handler) | |
131 | SCM tag; | |
132 | SCM thunk; | |
133 | SCM handler; | |
134 | #endif | |
135 | { | |
136 | struct jmp_buf_and_retval jbr; | |
137 | SCM jmpbuf; | |
138 | SCM answer; | |
139 | ||
140 | SCM_ASSERT ((tag == SCM_BOOL_F) || (SCM_NIMP(tag) && SCM_SYMBOLP(tag)) || (tag == SCM_BOOL_T), | |
141 | tag, SCM_ARG1, s_catch); | |
142 | jmpbuf = make_jmpbuf (); | |
143 | answer = SCM_EOL; | |
144 | scm_dynwinds = scm_acons (tag, jmpbuf, scm_dynwinds); | |
145 | SETJBJMPBUF(jmpbuf, &jbr.buf); | |
146 | #ifdef DEBUG_EXTENSIONS | |
147 | SETJBSCM_DFRAME(jmpbuf, last_debug_info_frame); | |
148 | #endif | |
149 | if (setjmp (jbr.buf)) | |
150 | { | |
151 | SCM throw_tag; | |
152 | SCM throw_args; | |
153 | ||
154 | SCM_DEFER_INTS; | |
155 | DEACTIVATEJB (jmpbuf); | |
156 | scm_dynwinds = SCM_CDR (scm_dynwinds); | |
157 | SCM_ALLOW_INTS; | |
158 | throw_args = jbr.retval; | |
159 | throw_tag = jbr.throw_tag; | |
160 | jbr.throw_tag = SCM_EOL; | |
161 | jbr.retval = SCM_EOL; | |
162 | answer = scm_apply (handler, scm_cons (throw_tag, throw_args), SCM_EOL); | |
163 | } | |
164 | else | |
165 | { | |
166 | ACTIVATEJB (jmpbuf); | |
167 | answer = scm_apply (thunk, | |
168 | ((tag == SCM_BOOL_F) ? scm_cons (jmpbuf, SCM_EOL) : SCM_EOL), | |
169 | SCM_EOL); | |
170 | SCM_DEFER_INTS; | |
171 | DEACTIVATEJB (jmpbuf); | |
172 | scm_dynwinds = SCM_CDR (scm_dynwinds); | |
173 | SCM_ALLOW_INTS; | |
174 | } | |
175 | return answer; | |
176 | } | |
177 | ||
178 | ||
179 | static char s_throw[]; | |
180 | #ifdef __STDC__ | |
181 | SCM | |
182 | scm_ithrow (SCM key, SCM args, int noreturn) | |
183 | #else | |
184 | SCM | |
185 | scm_ithrow (key, args, noreturn) | |
186 | SCM key; | |
187 | SCM args; | |
188 | int noreturn; | |
189 | #endif | |
190 | { | |
191 | SCM jmpbuf; | |
192 | SCM wind_goal; | |
193 | ||
194 | if (SCM_NIMP (key) && SCM_JMPBUFP (key)) | |
195 | { | |
196 | jmpbuf = key; | |
197 | if (noreturn) | |
198 | { | |
199 | SCM_ASSERT (JBACTIVE (jmpbuf), jmpbuf, | |
200 | "throw to dynamically inactive catch", | |
201 | s_throw); | |
202 | } | |
203 | else if (!JBACTIVE (jmpbuf)) | |
204 | return SCM_UNSPECIFIED; | |
205 | } | |
206 | else | |
207 | { | |
208 | SCM dynpair; | |
209 | SCM hook; | |
210 | ||
211 | if (noreturn) | |
212 | { | |
213 | SCM_ASSERT (SCM_NIMP (key) && SCM_SYMBOLP (key), key, SCM_ARG1, s_throw); | |
214 | } | |
215 | else if (!(SCM_NIMP (key) && SCM_SYMBOLP (key))) | |
216 | return SCM_UNSPECIFIED; | |
217 | ||
218 | dynpair = scm_sloppy_assq (key, scm_dynwinds); | |
219 | ||
220 | if (dynpair == SCM_BOOL_F) | |
221 | dynpair = scm_sloppy_assq (SCM_BOOL_T, scm_dynwinds); | |
222 | ||
223 | hook = SCM_CDR (scm_bad_throw_vcell); | |
224 | if ((dynpair == SCM_BOOL_F) | |
225 | && (SCM_BOOL_T == scm_procedure_p (hook))) | |
226 | { | |
227 | SCM answer; | |
228 | answer = scm_apply (hook, scm_cons (key, args), SCM_EOL); | |
229 | } | |
230 | ||
231 | if (dynpair != SCM_BOOL_F) | |
232 | jmpbuf = SCM_CDR (dynpair); | |
233 | else | |
234 | { | |
235 | if (!noreturn) | |
236 | return SCM_UNSPECIFIED; | |
237 | else | |
238 | { | |
239 | scm_exitval = scm_cons (key, args); | |
240 | scm_dowinds (SCM_EOL, scm_ilength (scm_dynwinds)); | |
241 | longjmp (SCM_JMPBUF (scm_rootcont), 1); | |
242 | } | |
243 | } | |
244 | } | |
245 | #ifdef DEBUG_EXTENSIONS | |
246 | last_debug_info_frame = JBSCM_DFRAME (jmpbuf); | |
247 | #endif | |
248 | for (wind_goal = scm_dynwinds; | |
249 | SCM_CDAR (wind_goal) != jmpbuf; | |
250 | wind_goal = SCM_CDR (wind_goal)) | |
251 | ; | |
252 | { | |
253 | struct jmp_buf_and_retval * jbr; | |
254 | jbr = (struct jmp_buf_and_retval *)JBJMPBUF (jmpbuf); | |
255 | jbr->throw_tag = key; | |
256 | jbr->retval = args; | |
257 | } | |
258 | scm_dowinds (wind_goal, scm_ilength (scm_dynwinds) - scm_ilength (wind_goal)); | |
259 | longjmp (*JBJMPBUF (jmpbuf), 1); | |
260 | } | |
261 | ||
262 | ||
263 | SCM_PROC(s_throw, "throw", 1, 0, 1, scm_throw); | |
264 | #ifdef __STDC__ | |
265 | SCM | |
266 | scm_throw (SCM key, SCM args) | |
267 | #else | |
268 | SCM | |
269 | scm_throw (key, args) | |
270 | SCM key; | |
271 | SCM args; | |
272 | #endif | |
273 | { | |
274 | scm_ithrow (key, args, 1); | |
275 | return SCM_BOOL_F; /* never really returns */ | |
276 | } | |
277 | ||
278 | ||
279 | #ifdef __STDC__ | |
280 | void | |
281 | scm_init_throw (void) | |
282 | #else | |
283 | void | |
284 | scm_init_throw () | |
285 | #endif | |
286 | { | |
287 | scm_tc16_jmpbuffer = scm_newsmob (&jbsmob); | |
288 | scm_bad_throw_vcell = scm_sysintern ("%%bad-throw", SCM_BOOL_F); | |
289 | #include "throw.x" | |
290 | } | |
291 |