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1 /* The "lrecord" structure (header of a compound lisp object).
2 Copyright (C) 1993, 1994, 1995 Free Software Foundation, Inc.
3 Copyright (C) 1996 Ben Wing.
4
5 This file is part of XEmacs.
6
7 XEmacs is free software; you can redistribute it and/or modify it
8 under the terms of the GNU General Public License as published by the
9 Free Software Foundation; either version 2, or (at your option) any
10 later version.
11
12 XEmacs is distributed in the hope that it will be useful, but WITHOUT
13 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
15 for more details.
16
17 You should have received a copy of the GNU General Public License
18 along with XEmacs; see the file COPYING. If not, write to
19 the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
20 Boston, MA 02111-1307, USA. */
21
22 /* Synched up with: Not in FSF. */
23
24 #ifndef _XEMACS_LRECORD_H_
25 #define _XEMACS_LRECORD_H_
26
27 /* The "lrecord" type of Lisp object is used for all object types
28 other than a few simple ones. This allows many types to be
29 implemented but only a few bits required in a Lisp object for
30 type information. (The tradeoff is that each object has its
31 type marked in it, thereby increasing its size.) The first
32 four bytes of all lrecords is either a pointer to a struct
33 lrecord_implementation, which contains methods describing how
34 to process this object, or an index into an array of pointers
35 to struct lrecord_implementations plus some other data bits.
36
37 Lrecords are of two types: straight lrecords, and lcrecords.
38 Straight lrecords are used for those types of objects that have
39 their own allocation routines (typically allocated out of 2K chunks
40 of memory called `frob blocks'). These objects have a `struct
41 lrecord_header' at the top, containing only the bits needed to find
42 the lrecord_implementation for the object. There are special
43 routines in alloc.c to deal with each such object type.
44
45 Lcrecords are used for less common sorts of objects that don't
46 do their own allocation. Each such object is malloc()ed
47 individually, and the objects are chained together through
48 a `next' pointer. Lcrecords have a `struct lcrecord_header'
49 at the top, which contains a `struct lrecord_header' and
50 a `next' pointer, and are allocated using alloc_lcrecord().
51
52 Creating a new lcrecord type is fairly easy; just follow the
53 lead of some existing type (e.g. hash tables). Note that you
54 do not need to supply all the methods (see below); reasonable
55 defaults are provided for many of them. Alternatively, if you're
56 just looking for a way of encapsulating data (which possibly
57 could contain Lisp_Objects in it), you may well be able to use
58 the opaque type. */
59
60 struct lrecord_header
61 {
62 /* index into lrecord_implementations_table[] */
63 unsigned type :8;
64 /* 1 if the object is marked during GC. */
65 unsigned mark :1;
66 /* 1 if the object resides in read-only space */
67 unsigned c_readonly : 1;
68 /* 1 if the object is readonly from lisp */
69 unsigned lisp_readonly : 1;
70 };
71
72 struct lrecord_implementation;
73 int lrecord_type_index (CONST struct lrecord_implementation *implementation);
74
75 # define set_lheader_implementation(header,imp) do { \
76 struct lrecord_header* SLI_header = (header); \
77 (SLI_header)->type = lrecord_type_index (imp); \
78 (SLI_header)->mark = 0; \
79 (SLI_header)->c_readonly = 0; \
80 (SLI_header)->lisp_readonly = 0; \
81 } while (0)
82
83 struct lcrecord_header
84 {
85 struct lrecord_header lheader;
86
87 /* The `next' field is normally used to chain all lrecords together
88 so that the GC can find (and free) all of them.
89 `alloc_lcrecord' threads records together.
90
91 The `next' field may be used for other purposes as long as some
92 other mechanism is provided for letting the GC do its work.
93
94 For example, the event and marker object types allocate members
95 out of memory chunks, and are able to find all unmarked members
96 by sweeping through the elements of the list of chunks. */
97 struct lcrecord_header *next;
98
99 /* The `uid' field is just for debugging/printing convenience.
100 Having this slot doesn't hurt us much spacewise, since an
101 lcrecord already has the above slots plus malloc overhead. */
102 unsigned int uid :31;
103
104 /* The `free' field is a flag that indicates whether this lcrecord
105 is on a "free list". Free lists are used to minimize the number
106 of calls to malloc() when we're repeatedly allocating and freeing
107 a number of the same sort of lcrecord. Lcrecords on a free list
108 always get marked in a different fashion, so we can use this flag
109 as a sanity check to make sure that free lists only have freed
110 lcrecords and there are no freed lcrecords elsewhere. */
111 unsigned int free :1;
112 };
113
114 /* Used for lcrecords in an lcrecord-list. */
115 struct free_lcrecord_header
116 {
117 struct lcrecord_header lcheader;
118 Lisp_Object chain;
119 };
120
121 /* see alloc.c for an explanation */
122 Lisp_Object this_one_is_unmarkable (Lisp_Object obj);
123
124 struct lrecord_implementation
125 {
126 CONST char *name;
127 /* This function is called at GC time, to make sure that all Lisp_Objects
128 pointed to by this object get properly marked. It should call
129 the mark_object function on all Lisp_Objects in the object. If
130 the return value is non-nil, it should be a Lisp_Object to be
131 marked (don't call the mark_object function explicitly on it,
132 because the GC routines will do this). Doing it this way reduces
133 recursion, so the object returned should preferably be the one
134 with the deepest level of Lisp_Object pointers. This function
135 can be NULL, meaning no GC marking is necessary. */
136 Lisp_Object (*marker) (Lisp_Object);
137 /* This can be NULL if the object is an lcrecord; the
138 default_object_printer() in print.c will be used. */
139 void (*printer) (Lisp_Object, Lisp_Object printcharfun, int escapeflag);
140 /* This function is called at GC time when the object is about to
141 be freed, and at dump time (FOR_DISKSAVE will be non-zero in this
142 case). It should perform any necessary cleanup (e.g. freeing
143 malloc()ed memory. This can be NULL, meaning no special
144 finalization is necessary.
145
146 WARNING: remember that the finalizer is called at dump time even
147 though the object is not being freed. */
148 void (*finalizer) (void *header, int for_disksave);
149 /* This can be NULL, meaning compare objects with EQ(). */
150 int (*equal) (Lisp_Object obj1, Lisp_Object obj2, int depth);
151 /* This can be NULL, meaning use the Lisp_Object itself as the hash;
152 but *only* if the `equal' function is EQ (if two objects are
153 `equal', they *must* hash to the same value or the hashing won't
154 work). */
155 unsigned long (*hash) (Lisp_Object, int);
156
157 /* External data layout description */
158 const struct lrecord_description *description;
159
160 Lisp_Object (*getprop) (Lisp_Object obj, Lisp_Object prop);
161 int (*putprop) (Lisp_Object obj, Lisp_Object prop, Lisp_Object val);
162 int (*remprop) (Lisp_Object obj, Lisp_Object prop);
163 Lisp_Object (*plist) (Lisp_Object obj);
164
165 /* Only one of these is non-0. If both are 0, it means that this type
166 is not instantiable by alloc_lcrecord(). */
167 size_t static_size;
168 size_t (*size_in_bytes_method) (CONST void *header);
169 /* A unique subtag-code (dynamically) assigned to this datatype. */
170 /* (This is a pointer so the rest of this structure can be read-only.) */
171 int *lrecord_type_index;
172 /* A "basic" lrecord is any lrecord that's not an lcrecord, i.e.
173 one that does not have an lcrecord_header at the front and which
174 is (usually) allocated in frob blocks. We only use this flag for
175 some consistency checking, and that only when error-checking is
176 enabled. */
177 int basic_p;
178 };
179
180 extern CONST struct lrecord_implementation *lrecord_implementations_table[];
181
182 #define XRECORD_LHEADER_IMPLEMENTATION(obj) \
183 (lrecord_implementations_table[XRECORD_LHEADER (obj)->type])
184 #define LHEADER_IMPLEMENTATION(lh) (lrecord_implementations_table[(lh)->type])
185
186 extern int gc_in_progress;
187
188 #define MARKED_RECORD_P(obj) (gc_in_progress && XRECORD_LHEADER (obj)->mark)
189 #define MARKED_RECORD_HEADER_P(lheader) ((lheader)->mark)
190 #define MARK_RECORD_HEADER(lheader) ((void) ((lheader)->mark = 1))
191 #define UNMARK_RECORD_HEADER(lheader) ((void) ((lheader)->mark = 0))
192
193 #define UNMARKABLE_RECORD_HEADER_P(lheader) \
194 (LHEADER_IMPLEMENTATION (lheader)->marker == this_one_is_unmarkable)
195
196 #define C_READONLY_RECORD_HEADER_P(lheader) ((lheader)->c_readonly)
197 #define LISP_READONLY_RECORD_HEADER_P(lheader) ((lheader)->lisp_readonly)
198 #define SET_C_READONLY_RECORD_HEADER(lheader) \
199 ((void) ((lheader)->c_readonly = (lheader)->lisp_readonly = 1))
200 #define SET_LISP_READONLY_RECORD_HEADER(lheader) \
201 ((void) ((lheader)->lisp_readonly = 1))
202
203 /* External description stuff
204
205 A lrecord external description is an array of values. The first
206 value of each line is a type, the second the offset in the lrecord
207 structure. Following values are parameters, their presence, type
208 and number is type-dependant.
209
210 The description ends with a "XD_END" or "XD_SPECIFIER_END" record.
211
212 Some example descriptions :
213 static const struct lrecord_description cons_description[] = {
214 { XD_LISP_OBJECT, offsetof(struct Lisp_Cons, car), 2 },
215 { XD_END }
216 };
217
218 Which means "two lisp objects starting at the 'car' element"
219
220 static const struct lrecord_description string_description[] = {
221 { XD_BYTECOUNT, offsetof(Lisp_String, size) },
222 { XD_OPAQUE_DATA_PTR, offsetof(Lisp_String, data), XD_INDIRECT(0, 1) },
223 { XD_LISP_OBJECT, offsetof(Lisp_String, plist), 1 },
224 { XD_END }
225 };
226 "A pointer to string data at 'data', the size of the pointed array being the value
227 of the size variable plus 1, and one lisp object at 'plist'"
228
229 The existing types :
230 XD_LISP_OBJECT
231 Lisp objects. The third element is the count. This is also the type to use
232 for pointers to other lrecords.
233
234 XD_LO_RESET_NIL
235 Lisp objects which will be reset to Qnil when dumping. Useful for cleaning
236 up caches.
237
238 XD_LO_LINK
239 Link in a linked list of objects of the same type.
240
241 XD_OPAQUE_PTR
242 Pointer to undumpable data. Must be NULL when dumping.
243
244 XD_STRUCT_PTR
245 Pointer to described struct. Parameters are number of structures and
246 struct_description.
247
248 XD_OPAQUE_DATA_PTR
249 Pointer to dumpable opaque data. Parameter is the size of the data.
250 Pointed data must be relocatable without changes.
251
252 XD_C_STRING
253 Pointer to a C string.
254
255 XD_DOC_STRING
256 Pointer to a doc string (C string if positive, opaque value if negative)
257
258 XD_INT_RESET
259 An integer which will be reset to a given value in the dump file.
260
261
262 XD_SIZE_T
263 size_t value. Used for counts.
264
265 XD_INT
266 int value. Used for counts.
267
268 XD_LONG
269 long value. Used for counts.
270
271 XD_BYTECOUNT
272 bytecount value. Used for counts.
273
274 XD_END
275 Special type indicating the end of the array.
276
277 XD_SPECIFIER_END
278 Special type indicating the end of the array for a specifier. Extra
279 description is going to be fetched from the specifier methods.
280
281
282 Special macros:
283 XD_INDIRECT(line, delta)
284 Usable where a "count" or "size" is requested. Gives the value of
285 the element which is at line number 'line' in the description (count
286 starts at zero) and adds delta to it.
287 */
288
289 enum lrecord_description_type {
290 XD_LISP_OBJECT,
291 XD_LO_RESET_NIL,
292 XD_LO_LINK,
293 XD_OPAQUE_PTR,
294 XD_STRUCT_PTR,
295 XD_OPAQUE_DATA_PTR,
296 XD_C_STRING,
297 XD_DOC_STRING,
298 XD_INT_RESET,
299 XD_SIZE_T,
300 XD_INT,
301 XD_LONG,
302 XD_BYTECOUNT,
303 XD_END,
304 XD_SPECIFIER_END
305 };
306
307 struct lrecord_description {
308 enum lrecord_description_type type;
309 int offset;
310 EMACS_INT data1;
311 const struct struct_description *data2;
312 };
313
314 struct struct_description {
315 size_t size;
316 const struct lrecord_description *description;
317 };
318
319 #define XD_INDIRECT(val, delta) (-1-((val)|(delta<<8)))
320
321 #define XD_IS_INDIRECT(code) (code<0)
322 #define XD_INDIRECT_VAL(code) ((-1-code) & 255)
323 #define XD_INDIRECT_DELTA(code) (((-1-code)>>8) & 255)
324
325 #define XD_DYNARR_DESC(base_type, sub_desc) \
326 { XD_STRUCT_PTR, offsetof(base_type, base), XD_INDIRECT(1, 0), sub_desc }, \
327 { XD_INT, offsetof(base_type, cur) }, \
328 { XD_INT_RESET, offsetof(base_type, max), XD_INDIRECT(1, 0) }
329
330 /* Declaring the following structures as const puts them in the
331 text (read-only) segment, which makes debugging inconvenient
332 because this segment is not mapped when processing a core-
333 dump file */
334
335 #ifdef DEBUG_XEMACS
336 #define CONST_IF_NOT_DEBUG
337 #else
338 #define CONST_IF_NOT_DEBUG CONST
339 #endif
340
341 /* DEFINE_LRECORD_IMPLEMENTATION is for objects with constant size.
342 DEFINE_LRECORD_SEQUENCE_IMPLEMENTATION is for objects whose size varies.
343 */
344
345 #if defined (ERROR_CHECK_TYPECHECK)
346 # define DECLARE_ERROR_CHECK_TYPECHECK(c_name, structtype)
347 #else
348 # define DECLARE_ERROR_CHECK_TYPECHECK(c_name, structtype)
349 #endif
350
351 #define DEFINE_BASIC_LRECORD_IMPLEMENTATION(name,c_name,marker,printer,nuker,equal,hash,desc,structtype) \
352 DEFINE_BASIC_LRECORD_IMPLEMENTATION_WITH_PROPS(name,c_name,marker,printer,nuker,equal,hash,desc,0,0,0,0,structtype)
353
354 #define DEFINE_BASIC_LRECORD_IMPLEMENTATION_WITH_PROPS(name,c_name,marker,printer,nuker,equal,hash,desc,getprop,putprop,remprop,props,structtype) \
355 MAKE_LRECORD_IMPLEMENTATION(name,c_name,marker,printer,nuker,equal,hash,desc,getprop,putprop,remprop,props,sizeof(structtype),0,1,structtype)
356
357 #define DEFINE_LRECORD_IMPLEMENTATION(name,c_name,marker,printer,nuker,equal,hash,desc,structtype) \
358 DEFINE_LRECORD_IMPLEMENTATION_WITH_PROPS(name,c_name,marker,printer,nuker,equal,hash,desc,0,0,0,0,structtype)
359
360 #define DEFINE_LRECORD_IMPLEMENTATION_WITH_PROPS(name,c_name,marker,printer,nuker,equal,hash,desc,getprop,putprop,remprop,props,structtype) \
361 MAKE_LRECORD_IMPLEMENTATION(name,c_name,marker,printer,nuker,equal,hash,desc,getprop,putprop,remprop,props,sizeof (structtype),0,0,structtype)
362
363 #define DEFINE_LRECORD_SEQUENCE_IMPLEMENTATION(name,c_name,marker,printer,nuker,equal,hash,desc,sizer,structtype) \
364 DEFINE_LRECORD_SEQUENCE_IMPLEMENTATION_WITH_PROPS(name,c_name,marker,printer,nuker,equal,hash,desc,0,0,0,0,sizer,structtype)
365
366 #define DEFINE_LRECORD_SEQUENCE_IMPLEMENTATION_WITH_PROPS(name,c_name,marker,printer,nuker,equal,hash,desc,getprop,putprop,remprop,props,sizer,structtype) \
367 MAKE_LRECORD_IMPLEMENTATION(name,c_name,marker,printer,nuker,equal,hash,desc,getprop,putprop,remprop,props,0,sizer,0,structtype) \
368
369 #define MAKE_LRECORD_IMPLEMENTATION(name,c_name,marker,printer,nuker,equal,hash,desc,getprop,putprop,remprop,props,size,sizer,basic_p,structtype) \
370 DECLARE_ERROR_CHECK_TYPECHECK(c_name, structtype) \
371 static int lrecord_##c_name##_lrecord_type_index; \
372 CONST_IF_NOT_DEBUG struct lrecord_implementation lrecord_##c_name = \
373 { name, marker, printer, nuker, equal, hash, desc, \
374 getprop, putprop, remprop, props, size, sizer, \
375 &(lrecord_##c_name##_lrecord_type_index), basic_p } \
376
377 #define LRECORDP(a) (XTYPE (a) == Lisp_Type_Record)
378 #define XRECORD_LHEADER(a) ((struct lrecord_header *) XPNTR (a))
379
380 #define RECORD_TYPEP(x, ty) \
381 (LRECORDP (x) && \
382 lrecord_implementations_table[XRECORD_LHEADER (x)->type] == (ty))
383
384 /* NOTE: the DECLARE_LRECORD() must come before the associated
385 DEFINE_LRECORD_*() or you will get compile errors.
386
387 Furthermore, you always need to put the DECLARE_LRECORD() in a header
388 file, and make sure the header file is included in inline.c, even
389 if the type is private to a particular file. Otherwise, you will
390 get undefined references for the error_check_foo() inline function
391 under GCC. */
392
393 #ifdef ERROR_CHECK_TYPECHECK
394
395 # define DECLARE_LRECORD(c_name, structtype) \
396 extern CONST_IF_NOT_DEBUG struct lrecord_implementation \
397 lrecord_##c_name; \
398 INLINE structtype *error_check_##c_name (Lisp_Object obj); \
399 INLINE structtype * \
400 error_check_##c_name (Lisp_Object obj) \
401 { \
402 assert (RECORD_TYPEP (obj, &lrecord_##c_name)); \
403 return (structtype *) XPNTR (obj); \
404 } \
405 extern Lisp_Object Q##c_name##p
406
407 # define DECLARE_NONRECORD(c_name, type_enum, structtype) \
408 INLINE structtype *error_check_##c_name (Lisp_Object obj); \
409 INLINE structtype * \
410 error_check_##c_name (Lisp_Object obj) \
411 { \
412 assert (XTYPE (obj) == type_enum); \
413 return (structtype *) XPNTR (obj); \
414 } \
415 extern Lisp_Object Q##c_name##p
416
417 # define XRECORD(x, c_name, structtype) error_check_##c_name (x)
418 # define XNONRECORD(x, c_name, type_enum, structtype) error_check_##c_name (x)
419
420 # define XSETRECORD(var, p, c_name) do \
421 { \
422 XSETOBJ (var, Lisp_Type_Record, p); \
423 assert (RECORD_TYPEP (var, &lrecord_##c_name)); \
424 } while (0)
425
426 #else /* not ERROR_CHECK_TYPECHECK */
427
428 # define DECLARE_LRECORD(c_name, structtype) \
429 extern Lisp_Object Q##c_name##p; \
430 extern CONST_IF_NOT_DEBUG struct lrecord_implementation \
431 lrecord_##c_name
432 # define DECLARE_NONRECORD(c_name, type_enum, structtype) \
433 extern Lisp_Object Q##c_name##p
434 # define XRECORD(x, c_name, structtype) ((structtype *) XPNTR (x))
435 # define XNONRECORD(x, c_name, type_enum, structtype) \
436 ((structtype *) XPNTR (x))
437 # define XSETRECORD(var, p, c_name) XSETOBJ (var, Lisp_Type_Record, p)
438
439 #endif /* not ERROR_CHECK_TYPECHECK */
440
441 #define RECORDP(x, c_name) RECORD_TYPEP (x, &lrecord_##c_name)
442
443 /* Note: we now have two different kinds of type-checking macros.
444 The "old" kind has now been renamed CONCHECK_foo. The reason for
445 this is that the CONCHECK_foo macros signal a continuable error,
446 allowing the user (through debug-on-error) to substitute a different
447 value and return from the signal, which causes the lvalue argument
448 to get changed. Quite a lot of code would crash if that happened,
449 because it did things like
450
451 foo = XCAR (list);
452 CHECK_STRING (foo);
453
454 and later on did XSTRING (XCAR (list)), assuming that the type
455 is correct (when it might be wrong, if the user substituted a
456 correct value in the debugger).
457
458 To get around this, I made all the CHECK_foo macros signal a
459 non-continuable error. Places where a continuable error is OK
460 (generally only when called directly on the argument of a Lisp
461 primitive) should be changed to use CONCHECK().
462
463 FSF Emacs does not have this problem because RMS took the cheesy
464 way out and disabled returning from a signal entirely. */
465
466 #define CONCHECK_RECORD(x, c_name) do { \
467 if (!RECORD_TYPEP (x, &lrecord_##c_name)) \
468 x = wrong_type_argument (Q##c_name##p, x); \
469 } while (0)
470 #define CONCHECK_NONRECORD(x, lisp_enum, predicate) do {\
471 if (XTYPE (x) != lisp_enum) \
472 x = wrong_type_argument (predicate, x); \
473 } while (0)
474 #define CHECK_RECORD(x, c_name) do { \
475 if (!RECORD_TYPEP (x, &lrecord_##c_name)) \
476 dead_wrong_type_argument (Q##c_name##p, x); \
477 } while (0)
478 #define CHECK_NONRECORD(x, lisp_enum, predicate) do { \
479 if (XTYPE (x) != lisp_enum) \
480 dead_wrong_type_argument (predicate, x); \
481 } while (0)
482
483 void *alloc_lcrecord (size_t size, CONST struct lrecord_implementation *);
484
485 #define alloc_lcrecord_type(type, lrecord_implementation) \
486 ((type *) alloc_lcrecord (sizeof (type), lrecord_implementation))
487
488 /* Copy the data from one lcrecord structure into another, but don't
489 overwrite the header information. */
490
491 #define copy_lcrecord(dst, src) \
492 memcpy ((char *) dst + sizeof (struct lcrecord_header), \
493 (char *) src + sizeof (struct lcrecord_header), \
494 sizeof (*dst) - sizeof (struct lcrecord_header))
495
496 #define zero_lcrecord(lcr) \
497 memset ((char *) lcr + sizeof (struct lcrecord_header), 0, \
498 sizeof (*lcr) - sizeof (struct lcrecord_header))
499
500 #endif /* _XEMACS_LRECORD_H_ */