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 INCLUDED_lrecord_h_
25 #define INCLUDED_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);
124 struct lrecord_implementation
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.
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
155 unsigned long (*hash) (Lisp_Object, int);
157 /* External data layout description */
158 const struct lrecord_description *description;
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);
165 /* Only one of these is non-0. If both are 0, it means that this type
166 is not instantiable by alloc_lcrecord(). */
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
180 extern CONST struct lrecord_implementation *lrecord_implementations_table[];
182 #define XRECORD_LHEADER_IMPLEMENTATION(obj) \
183 (lrecord_implementations_table[XRECORD_LHEADER (obj)->type])
184 #define LHEADER_IMPLEMENTATION(lh) (lrecord_implementations_table[(lh)->type])
186 extern int gc_in_progress;
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))
193 #define UNMARKABLE_RECORD_HEADER_P(lheader) \
194 (LHEADER_IMPLEMENTATION (lheader)->marker == this_one_is_unmarkable)
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))
203 /* External description stuff
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.
210 The description ends with a "XD_END" or "XD_SPECIFIER_END" record.
212 Some example descriptions :
214 static const struct lrecord_description cons_description[] = {
215 { XD_LISP_OBJECT, offsetof (Lisp_Cons, car) },
216 { XD_LISP_OBJECT, offsetof (Lisp_Cons, cdr) },
220 Which means "two lisp objects starting at the 'car' and 'cdr' elements"
222 static const struct lrecord_description string_description[] = {
223 { XD_BYTECOUNT, offsetof (Lisp_String, size) },
224 { XD_OPAQUE_DATA_PTR, offsetof (Lisp_String, data), XD_INDIRECT(0, 1) },
225 { XD_LISP_OBJECT, offsetof (Lisp_String, plist) },
228 "A pointer to string data at 'data', the size of the pointed array being the value
229 of the size variable plus 1, and one lisp object at 'plist'"
233 A Lisp object. This is also the type to use for pointers to other lrecords.
236 An array of Lisp objects or pointers to lrecords.
237 The third element is the count.
240 Lisp objects which will be reset to Qnil when dumping. Useful for cleaning
244 Link in a linked list of objects of the same type.
247 Pointer to undumpable data. Must be NULL when dumping.
250 Pointer to described struct. Parameters are number of structures and
254 Pointer to dumpable opaque data. Parameter is the size of the data.
255 Pointed data must be relocatable without changes.
258 Pointer to a C string.
261 Pointer to a doc string (C string if positive, opaque value if negative)
264 An integer which will be reset to a given value in the dump file.
268 size_t value. Used for counts.
271 int value. Used for counts.
274 long value. Used for counts.
277 bytecount value. Used for counts.
280 Special type indicating the end of the array.
283 Special type indicating the end of the array for a specifier. Extra
284 description is going to be fetched from the specifier methods.
288 XD_INDIRECT(line, delta)
289 Usable where a "count" or "size" is requested. Gives the value of
290 the element which is at line number 'line' in the description (count
291 starts at zero) and adds delta to it.
294 enum lrecord_description_type {
295 XD_LISP_OBJECT_ARRAY,
313 struct lrecord_description {
314 enum lrecord_description_type type;
317 const struct struct_description *data2;
320 struct struct_description {
322 const struct lrecord_description *description;
325 #define XD_INDIRECT(val, delta) (-1-((val)|(delta<<8)))
327 #define XD_IS_INDIRECT(code) (code<0)
328 #define XD_INDIRECT_VAL(code) ((-1-code) & 255)
329 #define XD_INDIRECT_DELTA(code) (((-1-code)>>8) & 255)
331 #define XD_DYNARR_DESC(base_type, sub_desc) \
332 { XD_STRUCT_PTR, offsetof (base_type, base), XD_INDIRECT(1, 0), sub_desc }, \
333 { XD_INT, offsetof (base_type, cur) }, \
334 { XD_INT_RESET, offsetof (base_type, max), XD_INDIRECT(1, 0) }
336 /* Declaring the following structures as const puts them in the
337 text (read-only) segment, which makes debugging inconvenient
338 because this segment is not mapped when processing a core-
342 #define CONST_IF_NOT_DEBUG
344 #define CONST_IF_NOT_DEBUG CONST
347 /* DEFINE_LRECORD_IMPLEMENTATION is for objects with constant size.
348 DEFINE_LRECORD_SEQUENCE_IMPLEMENTATION is for objects whose size varies.
351 #if defined (ERROR_CHECK_TYPECHECK)
352 # define DECLARE_ERROR_CHECK_TYPECHECK(c_name, structtype)
354 # define DECLARE_ERROR_CHECK_TYPECHECK(c_name, structtype)
357 #define DEFINE_BASIC_LRECORD_IMPLEMENTATION(name,c_name,marker,printer,nuker,equal,hash,desc,structtype) \
358 DEFINE_BASIC_LRECORD_IMPLEMENTATION_WITH_PROPS(name,c_name,marker,printer,nuker,equal,hash,desc,0,0,0,0,structtype)
360 #define DEFINE_BASIC_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),0,1,structtype)
363 #define DEFINE_LRECORD_IMPLEMENTATION(name,c_name,marker,printer,nuker,equal,hash,desc,structtype) \
364 DEFINE_LRECORD_IMPLEMENTATION_WITH_PROPS(name,c_name,marker,printer,nuker,equal,hash,desc,0,0,0,0,structtype)
366 #define DEFINE_LRECORD_IMPLEMENTATION_WITH_PROPS(name,c_name,marker,printer,nuker,equal,hash,desc,getprop,putprop,remprop,props,structtype) \
367 MAKE_LRECORD_IMPLEMENTATION(name,c_name,marker,printer,nuker,equal,hash,desc,getprop,putprop,remprop,props,sizeof (structtype),0,0,structtype)
369 #define DEFINE_LRECORD_SEQUENCE_IMPLEMENTATION(name,c_name,marker,printer,nuker,equal,hash,desc,sizer,structtype) \
370 DEFINE_LRECORD_SEQUENCE_IMPLEMENTATION_WITH_PROPS(name,c_name,marker,printer,nuker,equal,hash,desc,0,0,0,0,sizer,structtype)
372 #define DEFINE_LRECORD_SEQUENCE_IMPLEMENTATION_WITH_PROPS(name,c_name,marker,printer,nuker,equal,hash,desc,getprop,putprop,remprop,props,sizer,structtype) \
373 MAKE_LRECORD_IMPLEMENTATION(name,c_name,marker,printer,nuker,equal,hash,desc,getprop,putprop,remprop,props,0,sizer,0,structtype) \
375 #define MAKE_LRECORD_IMPLEMENTATION(name,c_name,marker,printer,nuker,equal,hash,desc,getprop,putprop,remprop,props,size,sizer,basic_p,structtype) \
376 DECLARE_ERROR_CHECK_TYPECHECK(c_name, structtype) \
377 static int lrecord_##c_name##_lrecord_type_index; \
378 CONST_IF_NOT_DEBUG struct lrecord_implementation lrecord_##c_name = \
379 { name, marker, printer, nuker, equal, hash, desc, \
380 getprop, putprop, remprop, props, size, sizer, \
381 &(lrecord_##c_name##_lrecord_type_index), basic_p } \
383 #define LRECORDP(a) (XTYPE (a) == Lisp_Type_Record)
384 #define XRECORD_LHEADER(a) ((struct lrecord_header *) XPNTR (a))
386 #define RECORD_TYPEP(x, ty) \
388 lrecord_implementations_table[XRECORD_LHEADER (x)->type] == (ty))
390 /* NOTE: the DECLARE_LRECORD() must come before the associated
391 DEFINE_LRECORD_*() or you will get compile errors.
393 Furthermore, you always need to put the DECLARE_LRECORD() in a header
394 file, and make sure the header file is included in inline.c, even
395 if the type is private to a particular file. Otherwise, you will
396 get undefined references for the error_check_foo() inline function
399 #ifdef ERROR_CHECK_TYPECHECK
401 # define DECLARE_LRECORD(c_name, structtype) \
402 extern CONST_IF_NOT_DEBUG struct lrecord_implementation \
404 INLINE structtype *error_check_##c_name (Lisp_Object obj); \
405 INLINE structtype * \
406 error_check_##c_name (Lisp_Object obj) \
408 assert (RECORD_TYPEP (obj, &lrecord_##c_name)); \
409 return (structtype *) XPNTR (obj); \
411 extern Lisp_Object Q##c_name##p
413 # define DECLARE_NONRECORD(c_name, type_enum, structtype) \
414 INLINE structtype *error_check_##c_name (Lisp_Object obj); \
415 INLINE structtype * \
416 error_check_##c_name (Lisp_Object obj) \
418 assert (XTYPE (obj) == type_enum); \
419 return (structtype *) XPNTR (obj); \
421 extern Lisp_Object Q##c_name##p
423 # define XRECORD(x, c_name, structtype) error_check_##c_name (x)
424 # define XNONRECORD(x, c_name, type_enum, structtype) error_check_##c_name (x)
426 # define XSETRECORD(var, p, c_name) do \
428 XSETOBJ (var, Lisp_Type_Record, p); \
429 assert (RECORD_TYPEP (var, &lrecord_##c_name)); \
432 #else /* not ERROR_CHECK_TYPECHECK */
434 # define DECLARE_LRECORD(c_name, structtype) \
435 extern Lisp_Object Q##c_name##p; \
436 extern CONST_IF_NOT_DEBUG struct lrecord_implementation \
438 # define DECLARE_NONRECORD(c_name, type_enum, structtype) \
439 extern Lisp_Object Q##c_name##p
440 # define XRECORD(x, c_name, structtype) ((structtype *) XPNTR (x))
441 # define XNONRECORD(x, c_name, type_enum, structtype) \
442 ((structtype *) XPNTR (x))
443 # define XSETRECORD(var, p, c_name) XSETOBJ (var, Lisp_Type_Record, p)
445 #endif /* not ERROR_CHECK_TYPECHECK */
447 #define RECORDP(x, c_name) RECORD_TYPEP (x, &lrecord_##c_name)
449 /* Note: we now have two different kinds of type-checking macros.
450 The "old" kind has now been renamed CONCHECK_foo. The reason for
451 this is that the CONCHECK_foo macros signal a continuable error,
452 allowing the user (through debug-on-error) to substitute a different
453 value and return from the signal, which causes the lvalue argument
454 to get changed. Quite a lot of code would crash if that happened,
455 because it did things like
460 and later on did XSTRING (XCAR (list)), assuming that the type
461 is correct (when it might be wrong, if the user substituted a
462 correct value in the debugger).
464 To get around this, I made all the CHECK_foo macros signal a
465 non-continuable error. Places where a continuable error is OK
466 (generally only when called directly on the argument of a Lisp
467 primitive) should be changed to use CONCHECK().
469 FSF Emacs does not have this problem because RMS took the cheesy
470 way out and disabled returning from a signal entirely. */
472 #define CONCHECK_RECORD(x, c_name) do { \
473 if (!RECORD_TYPEP (x, &lrecord_##c_name)) \
474 x = wrong_type_argument (Q##c_name##p, x); \
476 #define CONCHECK_NONRECORD(x, lisp_enum, predicate) do {\
477 if (XTYPE (x) != lisp_enum) \
478 x = wrong_type_argument (predicate, x); \
480 #define CHECK_RECORD(x, c_name) do { \
481 if (!RECORD_TYPEP (x, &lrecord_##c_name)) \
482 dead_wrong_type_argument (Q##c_name##p, x); \
484 #define CHECK_NONRECORD(x, lisp_enum, predicate) do { \
485 if (XTYPE (x) != lisp_enum) \
486 dead_wrong_type_argument (predicate, x); \
489 void *alloc_lcrecord (size_t size, CONST struct lrecord_implementation *);
491 #define alloc_lcrecord_type(type, lrecord_implementation) \
492 ((type *) alloc_lcrecord (sizeof (type), lrecord_implementation))
494 /* Copy the data from one lcrecord structure into another, but don't
495 overwrite the header information. */
497 #define copy_lcrecord(dst, src) \
498 memcpy ((char *) (dst) + sizeof (struct lcrecord_header), \
499 (char *) (src) + sizeof (struct lcrecord_header), \
500 sizeof (*(dst)) - sizeof (struct lcrecord_header))
502 #define zero_lcrecord(lcr) \
503 memset ((char *) (lcr) + sizeof (struct lcrecord_header), 0, \
504 sizeof (*(lcr)) - sizeof (struct lcrecord_header))
506 #endif /* INCLUDED_lrecord_h_ */