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.
5 This file is part of XEmacs.
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
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
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. */
22 /* Synched up with: Not in FSF. */
24 #ifndef _XEMACS_LRECORD_H_
25 #define _XEMACS_LRECORD_H_
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.
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.
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().
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
62 /* index into lrecord_implementations_table[] */
64 /* 1 if the object is marked during GC. */
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;
72 struct lrecord_implementation;
73 int lrecord_type_index (CONST struct lrecord_implementation *implementation);
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; \
83 struct lcrecord_header
85 struct lrecord_header lheader;
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.
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.
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;
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;
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;
114 /* Used for lcrecords in an lcrecord-list. */
115 struct free_lcrecord_header
117 struct lcrecord_header lcheader;
121 /* see alloc.c for an explanation */
122 Lisp_Object this_one_is_unmarkable (Lisp_Object obj,
123 void (*markobj) (Lisp_Object));
125 struct lrecord_implementation
128 /* This function is called at GC time, to make sure that all Lisp_Objects
129 pointed to by this object get properly marked. It should call
130 the mark_object function on all Lisp_Objects in the object. If
131 the return value is non-nil, it should be a Lisp_Object to be
132 marked (don't call the mark_object function explicitly on it,
133 because the GC routines will do this). Doing it this way reduces
134 recursion, so the object returned should preferably be the one
135 with the deepest level of Lisp_Object pointers. This function
136 can be NULL, meaning no GC marking is necessary. */
137 Lisp_Object (*marker) (Lisp_Object, void (*mark_object) (Lisp_Object));
138 /* This can be NULL if the object is an lcrecord; the
139 default_object_printer() in print.c will be used. */
140 void (*printer) (Lisp_Object, Lisp_Object printcharfun, int escapeflag);
141 /* This function is called at GC time when the object is about to
142 be freed, and at dump time (FOR_DISKSAVE will be non-zero in this
143 case). It should perform any necessary cleanup (e.g. freeing
144 malloc()ed memory. This can be NULL, meaning no special
145 finalization is necessary.
147 WARNING: remember that the finalizer is called at dump time even
148 though the object is not being freed. */
149 void (*finalizer) (void *header, int for_disksave);
150 /* This can be NULL, meaning compare objects with EQ(). */
151 int (*equal) (Lisp_Object obj1, Lisp_Object obj2, int depth);
152 /* This can be NULL, meaning use the Lisp_Object itself as the hash;
153 but *only* if the `equal' function is EQ (if two objects are
154 `equal', they *must* hash to the same value or the hashing won't
156 unsigned long (*hash) (Lisp_Object, int);
158 /* External data layout description */
159 const struct lrecord_description *description;
161 Lisp_Object (*getprop) (Lisp_Object obj, Lisp_Object prop);
162 int (*putprop) (Lisp_Object obj, Lisp_Object prop, Lisp_Object val);
163 int (*remprop) (Lisp_Object obj, Lisp_Object prop);
164 Lisp_Object (*plist) (Lisp_Object obj);
166 /* Only one of these is non-0. If both are 0, it means that this type
167 is not instantiable by alloc_lcrecord(). */
169 size_t (*size_in_bytes_method) (CONST void *header);
170 /* A unique subtag-code (dynamically) assigned to this datatype. */
171 /* (This is a pointer so the rest of this structure can be read-only.) */
172 int *lrecord_type_index;
173 /* A "basic" lrecord is any lrecord that's not an lcrecord, i.e.
174 one that does not have an lcrecord_header at the front and which
175 is (usually) allocated in frob blocks. We only use this flag for
176 some consistency checking, and that only when error-checking is
181 extern CONST struct lrecord_implementation *lrecord_implementations_table[];
183 #define XRECORD_LHEADER_IMPLEMENTATION(obj) \
184 (lrecord_implementations_table[XRECORD_LHEADER (obj)->type])
185 #define LHEADER_IMPLEMENTATION(lh) (lrecord_implementations_table[(lh)->type])
187 extern int gc_in_progress;
189 #define MARKED_RECORD_P(obj) (gc_in_progress && XRECORD_LHEADER (obj)->mark)
190 #define MARKED_RECORD_HEADER_P(lheader) ((lheader)->mark)
191 #define MARK_RECORD_HEADER(lheader) ((void) ((lheader)->mark = 1))
192 #define UNMARK_RECORD_HEADER(lheader) ((void) ((lheader)->mark = 0))
194 #define UNMARKABLE_RECORD_HEADER_P(lheader) \
195 (LHEADER_IMPLEMENTATION (lheader)->marker == this_one_is_unmarkable)
197 #define C_READONLY_RECORD_HEADER_P(lheader) ((lheader)->c_readonly)
198 #define LISP_READONLY_RECORD_HEADER_P(lheader) ((lheader)->lisp_readonly)
199 #define SET_C_READONLY_RECORD_HEADER(lheader) \
200 ((void) ((lheader)->c_readonly = (lheader)->lisp_readonly = 1))
201 #define SET_LISP_READONLY_RECORD_HEADER(lheader) \
202 ((void) ((lheader)->lisp_readonly = 1))
204 /* External description stuff
206 A lrecord external description is an array of values. The first
207 value of each line is a type, the second the offset in the lrecord
208 structure. Following values are parameters, their presence, type
209 and number is type-dependant.
211 The description ends with a "XD_END" record.
213 Some example descriptions :
214 static const struct lrecord_description cons_description[] = {
215 { XD_LISP_OBJECT, offsetof(struct Lisp_Cons, car), 2 },
219 Which means "two lisp objects starting at the 'car' element"
221 static const struct lrecord_description string_description[] = {
222 { XD_STRING_DATA, offsetof(Lisp_String, data) },
223 { XD_LISP_OBJECT, offsetof(Lisp_String, plist), 1 },
226 "A string data pointer at 'data', one lisp object at 'plist'"
230 Lisp objects. The third element is the count. This is also the type to use
231 for pointers to other lrecords.
234 Pointer to string data.
237 Pointer to undumpable data. Must be NULL when dumping.
240 Pointer to described struct. Parameters are number of structures and
244 Pointer to dumpable opaque data. Parameter is the size of the data.
245 Pointed data must be relocatable without changes.
248 size_t value. Used for counts.
251 int value. Used for counts.
254 long value. Used for counts.
257 Special type indicating the end of the array.
262 Usable where a "count" or "size" is requested. Gives the value of the element
263 which is at line number 'line' in the description (count starts at zero).
265 XD_PARENT_INDIRECT(line)
266 Same as XD_INDIRECT but the element number refers to the parent structure.
267 Usable only in struct descriptions.
270 enum lrecord_description_type {
282 struct lrecord_description {
283 enum lrecord_description_type type;
286 const struct struct_description *data2;
289 struct struct_description {
291 const struct lrecord_description *description;
294 #define XD_INDIRECT(count) (-1-(count))
295 #define XD_PARENT_INDIRECT(count) (-1000-(count))
297 #define XD_DYNARR_DESC(base_type, sub_desc) \
298 { XD_STRUCT_PTR, offsetof(base_type, base), XD_INDIRECT(1), sub_desc }, \
299 { XD_INT, offsetof(base_type, max) }
301 /* Declaring the following structures as const puts them in the
302 text (read-only) segment, which makes debugging inconvenient
303 because this segment is not mapped when processing a core-
307 #define CONST_IF_NOT_DEBUG
309 #define CONST_IF_NOT_DEBUG CONST
312 /* DEFINE_LRECORD_IMPLEMENTATION is for objects with constant size.
313 DEFINE_LRECORD_SEQUENCE_IMPLEMENTATION is for objects whose size varies.
316 #if defined (ERROR_CHECK_TYPECHECK)
317 # define DECLARE_ERROR_CHECK_TYPECHECK(c_name, structtype)
319 # define DECLARE_ERROR_CHECK_TYPECHECK(c_name, structtype)
322 #define DEFINE_BASIC_LRECORD_IMPLEMENTATION(name,c_name,marker,printer,nuker,equal,hash,desc,structtype) \
323 DEFINE_BASIC_LRECORD_IMPLEMENTATION_WITH_PROPS(name,c_name,marker,printer,nuker,equal,hash,desc,0,0,0,0,structtype)
325 #define DEFINE_BASIC_LRECORD_IMPLEMENTATION_WITH_PROPS(name,c_name,marker,printer,nuker,equal,hash,desc,getprop,putprop,remprop,props,structtype) \
326 MAKE_LRECORD_IMPLEMENTATION(name,c_name,marker,printer,nuker,equal,hash,desc,getprop,putprop,remprop,props,sizeof(structtype),0,1,structtype)
328 #define DEFINE_LRECORD_IMPLEMENTATION(name,c_name,marker,printer,nuker,equal,hash,desc,structtype) \
329 DEFINE_LRECORD_IMPLEMENTATION_WITH_PROPS(name,c_name,marker,printer,nuker,equal,hash,desc,0,0,0,0,structtype)
331 #define DEFINE_LRECORD_IMPLEMENTATION_WITH_PROPS(name,c_name,marker,printer,nuker,equal,hash,desc,getprop,putprop,remprop,props,structtype) \
332 MAKE_LRECORD_IMPLEMENTATION(name,c_name,marker,printer,nuker,equal,hash,desc,getprop,putprop,remprop,props,sizeof (structtype),0,0,structtype)
334 #define DEFINE_LRECORD_SEQUENCE_IMPLEMENTATION(name,c_name,marker,printer,nuker,equal,hash,desc,sizer,structtype) \
335 DEFINE_LRECORD_SEQUENCE_IMPLEMENTATION_WITH_PROPS(name,c_name,marker,printer,nuker,equal,hash,desc,0,0,0,0,sizer,structtype)
337 #define DEFINE_LRECORD_SEQUENCE_IMPLEMENTATION_WITH_PROPS(name,c_name,marker,printer,nuker,equal,hash,desc,getprop,putprop,remprop,props,sizer,structtype) \
338 MAKE_LRECORD_IMPLEMENTATION(name,c_name,marker,printer,nuker,equal,hash,desc,getprop,putprop,remprop,props,0,sizer,0,structtype) \
340 #define MAKE_LRECORD_IMPLEMENTATION(name,c_name,marker,printer,nuker,equal,hash,desc,getprop,putprop,remprop,props,size,sizer,basic_p,structtype) \
341 DECLARE_ERROR_CHECK_TYPECHECK(c_name, structtype) \
342 static int lrecord_##c_name##_lrecord_type_index; \
343 CONST_IF_NOT_DEBUG struct lrecord_implementation lrecord_##c_name = \
344 { name, marker, printer, nuker, equal, hash, desc, \
345 getprop, putprop, remprop, props, size, sizer, \
346 &(lrecord_##c_name##_lrecord_type_index), basic_p } \
348 #define LRECORDP(a) (XTYPE ((a)) == Lisp_Type_Record)
349 #define XRECORD_LHEADER(a) ((struct lrecord_header *) XPNTR (a))
351 #define RECORD_TYPEP(x, ty) \
353 lrecord_implementations_table[XRECORD_LHEADER (x)->type] == (ty))
355 /* NOTE: the DECLARE_LRECORD() must come before the associated
356 DEFINE_LRECORD_*() or you will get compile errors.
358 Furthermore, you always need to put the DECLARE_LRECORD() in a header
359 file, and make sure the header file is included in inline.c, even
360 if the type is private to a particular file. Otherwise, you will
361 get undefined references for the error_check_foo() inline function
364 #ifdef ERROR_CHECK_TYPECHECK
366 # define DECLARE_LRECORD(c_name, structtype) \
367 extern CONST_IF_NOT_DEBUG struct lrecord_implementation \
369 INLINE structtype *error_check_##c_name (Lisp_Object obj); \
370 INLINE structtype * \
371 error_check_##c_name (Lisp_Object obj) \
373 assert (RECORD_TYPEP (obj, &lrecord_##c_name) || \
374 MARKED_RECORD_P (obj)); \
375 return (structtype *) XPNTR (obj); \
377 extern Lisp_Object Q##c_name##p
379 # define DECLARE_NONRECORD(c_name, type_enum, structtype) \
380 INLINE structtype *error_check_##c_name (Lisp_Object obj); \
381 INLINE structtype * \
382 error_check_##c_name (Lisp_Object obj) \
384 assert (XGCTYPE (obj) == type_enum); \
385 return (structtype *) XPNTR (obj); \
387 extern Lisp_Object Q##c_name##p
389 # define XRECORD(x, c_name, structtype) error_check_##c_name (x)
390 # define XNONRECORD(x, c_name, type_enum, structtype) error_check_##c_name (x)
392 # define XSETRECORD(var, p, c_name) do \
394 XSETOBJ (var, Lisp_Type_Record, p); \
395 assert (RECORD_TYPEP (var, &lrecord_##c_name) || \
396 MARKED_RECORD_P (var)); \
399 #else /* not ERROR_CHECK_TYPECHECK */
401 # define DECLARE_LRECORD(c_name, structtype) \
402 extern Lisp_Object Q##c_name##p; \
403 extern CONST_IF_NOT_DEBUG struct lrecord_implementation \
405 # define DECLARE_NONRECORD(c_name, type_enum, structtype) \
406 extern Lisp_Object Q##c_name##p
407 # define XRECORD(x, c_name, structtype) ((structtype *) XPNTR (x))
408 # define XNONRECORD(x, c_name, type_enum, structtype) \
409 ((structtype *) XPNTR (x))
410 # define XSETRECORD(var, p, c_name) XSETOBJ (var, Lisp_Type_Record, p)
412 #endif /* not ERROR_CHECK_TYPECHECK */
414 #define RECORDP(x, c_name) RECORD_TYPEP (x, &lrecord_##c_name)
415 #define GC_RECORDP(x, c_name) gc_record_type_p (x, &lrecord_##c_name)
417 /* Note: we now have two different kinds of type-checking macros.
418 The "old" kind has now been renamed CONCHECK_foo. The reason for
419 this is that the CONCHECK_foo macros signal a continuable error,
420 allowing the user (through debug-on-error) to substitute a different
421 value and return from the signal, which causes the lvalue argument
422 to get changed. Quite a lot of code would crash if that happened,
423 because it did things like
428 and later on did XSTRING (XCAR (list)), assuming that the type
429 is correct (when it might be wrong, if the user substituted a
430 correct value in the debugger).
432 To get around this, I made all the CHECK_foo macros signal a
433 non-continuable error. Places where a continuable error is OK
434 (generally only when called directly on the argument of a Lisp
435 primitive) should be changed to use CONCHECK().
437 FSF Emacs does not have this problem because RMS took the cheesy
438 way out and disabled returning from a signal entirely. */
440 #define CONCHECK_RECORD(x, c_name) do { \
441 if (!RECORD_TYPEP (x, &lrecord_##c_name)) \
442 x = wrong_type_argument (Q##c_name##p, x); \
444 #define CONCHECK_NONRECORD(x, lisp_enum, predicate) do {\
445 if (XTYPE (x) != lisp_enum) \
446 x = wrong_type_argument (predicate, x); \
448 #define CHECK_RECORD(x, c_name) do { \
449 if (!RECORD_TYPEP (x, &lrecord_##c_name)) \
450 dead_wrong_type_argument (Q##c_name##p, x); \
452 #define CHECK_NONRECORD(x, lisp_enum, predicate) do { \
453 if (XTYPE (x) != lisp_enum) \
454 dead_wrong_type_argument (predicate, x); \
457 void *alloc_lcrecord (size_t size, CONST struct lrecord_implementation *);
459 #define alloc_lcrecord_type(type, lrecord_implementation) \
460 ((type *) alloc_lcrecord (sizeof (type), lrecord_implementation))
462 int gc_record_type_p (Lisp_Object frob,
463 CONST struct lrecord_implementation *type);
465 /* Copy the data from one lcrecord structure into another, but don't
466 overwrite the header information. */
468 #define copy_lcrecord(dst, src) \
469 memcpy ((char *) dst + sizeof (struct lcrecord_header), \
470 (char *) src + sizeof (struct lcrecord_header), \
471 sizeof (*dst) - sizeof (struct lcrecord_header))
473 #define zero_lcrecord(lcr) \
474 memset ((char *) lcr + sizeof (struct lcrecord_header), 0, \
475 sizeof (*lcr) - sizeof (struct lcrecord_header))
477 #endif /* _XEMACS_LRECORD_H_ */