xref: /plan9-contrib/sys/src/cmd/acme/elog.c (revision d46c239f8612929b7dbade67d0d071633df3a15d)
1 #include <u.h>
2 #include <libc.h>
3 #include <draw.h>
4 #include <thread.h>
5 #include <cursor.h>
6 #include <mouse.h>
7 #include <keyboard.h>
8 #include <frame.h>
9 #include <fcall.h>
10 #include <plumb.h>
11 #include "dat.h"
12 #include "fns.h"
13 #include "edit.h"
14 
15 static char Wsequence[] = "warning: changes out of sequence\n";
16 static int	warned = FALSE;
17 
18 /*
19  * Log of changes made by editing commands.  Three reasons for this:
20  * 1) We want addresses in commands to apply to old file, not file-in-change.
21  * 2) It's difficult to track changes correctly as things move, e.g. ,x m$
22  * 3) This gives an opportunity to optimize by merging adjacent changes.
23  * It's a little bit like the Undo/Redo log in Files, but Point 3) argues for a
24  * separate implementation.  To do this well, we use Replace as well as
25  * Insert and Delete
26  */
27 
28 typedef struct Buflog Buflog;
29 struct Buflog
30 {
31 	short	type;		/* Replace, Filename */
32 	uint		q0;		/* location of change (unused in f) */
33 	uint		nd;		/* # runes to delete */
34 	uint		nr;		/* # runes in string or file name */
35 };
36 
37 enum
38 {
39 	Buflogsize = sizeof(Buflog)/sizeof(Rune),
40 };
41 
42 /*
43  * Minstring shouldn't be very big or we will do lots of I/O for small changes.
44  * Maxstring is RBUFSIZE so we can fbufalloc() once and not realloc elog.r.
45  */
46 enum
47 {
48 	Minstring = 16,		/* distance beneath which we merge changes */
49 	Maxstring = RBUFSIZE,	/* maximum length of change we will merge into one */
50 };
51 
52 void
53 eloginit(File *f)
54 {
55 	if(f->elog.type != Empty)
56 		return;
57 	f->elog.type = Null;
58 	if(f->elogbuf == nil)
59 		f->elogbuf = emalloc(sizeof(Buffer));
60 	if(f->elog.r == nil)
61 		f->elog.r = fbufalloc();
62 	bufreset(f->elogbuf);
63 }
64 
65 void
66 elogclose(File *f)
67 {
68 	if(f->elogbuf){
69 		bufclose(f->elogbuf);
70 		free(f->elogbuf);
71 		f->elogbuf = nil;
72 	}
73 }
74 
75 void
76 elogreset(File *f)
77 {
78 	f->elog.type = Null;
79 	f->elog.nd = 0;
80 	f->elog.nr = 0;
81 }
82 
83 void
84 elogterm(File *f)
85 {
86 	elogreset(f);
87 	if(f->elogbuf)
88 		bufreset(f->elogbuf);
89 	f->elog.type = Empty;
90 	fbuffree(f->elog.r);
91 	f->elog.r = nil;
92 	warned = FALSE;
93 }
94 
95 void
96 elogflush(File *f)
97 {
98 	Buflog b;
99 
100 	b.type = f->elog.type;
101 	b.q0 = f->elog.q0;
102 	b.nd = f->elog.nd;
103 	b.nr = f->elog.nr;
104 	switch(f->elog.type){
105 	default:
106 		warning(nil, "unknown elog type 0x%ux\n", f->elog.type);
107 		break;
108 	case Null:
109 		break;
110 	case Insert:
111 	case Replace:
112 		if(f->elog.nr > 0)
113 			bufinsert(f->elogbuf, f->elogbuf->nc, f->elog.r, f->elog.nr);
114 		/* fall through */
115 	case Delete:
116 		bufinsert(f->elogbuf, f->elogbuf->nc, (Rune*)&b, Buflogsize);
117 		break;
118 	}
119 	elogreset(f);
120 }
121 
122 void
123 elogreplace(File *f, int q0, int q1, Rune *r, int nr)
124 {
125 	uint gap;
126 
127 	if(q0==q1 && nr==0)
128 		return;
129 	eloginit(f);
130 	if(f->elog.type!=Null && q0<f->elog.q0){
131 		if(warned++ == 0)
132 			warning(nil, Wsequence);
133 		elogflush(f);
134 	}
135 	/* try to merge with previous */
136 	gap = q0 - (f->elog.q0+f->elog.nd);	/* gap between previous and this */
137 	if(f->elog.type==Replace && f->elog.nr+gap+nr<Maxstring){
138 		if(gap < Minstring){
139 			if(gap > 0){
140 				bufread(f, f->elog.q0+f->elog.nd, f->elog.r+f->elog.nr, gap);
141 				f->elog.nr += gap;
142 			}
143 			f->elog.nd += gap + q1-q0;
144 			runemove(f->elog.r+f->elog.nr, r, nr);
145 			f->elog.nr += nr;
146 			return;
147 		}
148 	}
149 	elogflush(f);
150 	f->elog.type = Replace;
151 	f->elog.q0 = q0;
152 	f->elog.nd = q1-q0;
153 	f->elog.nr = nr;
154 	if(nr > RBUFSIZE)
155 		editerror("internal error: replacement string too large(%d)", nr);
156 	runemove(f->elog.r, r, nr);
157 }
158 
159 void
160 eloginsert(File *f, int q0, Rune *r, int nr)
161 {
162 	int n;
163 
164 	if(nr == 0)
165 		return;
166 	eloginit(f);
167 	if(f->elog.type!=Null && q0<f->elog.q0){
168 		if(warned++ == 0)
169 			warning(nil, Wsequence);
170 		elogflush(f);
171 	}
172 	/* try to merge with previous */
173 	if(f->elog.type==Insert && q0==f->elog.q0 && (q0+nr)-f->elog.q0<Maxstring){
174 		f->elog.r = runerealloc(f->elog.r, f->elog.nr+nr);
175 		runemove(f->elog.r+f->elog.nr, r, nr);
176 		f->elog.nr += nr;
177 		return;
178 	}
179 	while(nr > 0){
180 		elogflush(f);
181 		f->elog.type = Insert;
182 		f->elog.q0 = q0;
183 		n = nr;
184 		if(n > RBUFSIZE)
185 			n = RBUFSIZE;
186 		f->elog.nr = n;
187 		runemove(f->elog.r, r, n);
188 		r += n;
189 		nr -= n;
190 	}
191 }
192 
193 void
194 elogdelete(File *f, int q0, int q1)
195 {
196 	if(q0 == q1)
197 		return;
198 	eloginit(f);
199 	if(f->elog.type!=Null && q0<f->elog.q0+f->elog.nd){
200 		if(warned++ == 0)
201 			warning(nil, Wsequence);
202 		elogflush(f);
203 	}
204 	/* try to merge with previous */
205 	if(f->elog.type==Delete && f->elog.q0+f->elog.nd==q0){
206 		f->elog.nd += q1-q0;
207 		return;
208 	}
209 	elogflush(f);
210 	f->elog.type = Delete;
211 	f->elog.q0 = q0;
212 	f->elog.nd = q1-q0;
213 }
214 
215 void
216 elogapply(File *f)
217 {
218 	Buflog b;
219 	Rune *buf;
220 	uint i, n, up, mod;
221 	Buffer *log;
222 
223 	elogflush(f);
224 	log = f->elogbuf;
225 
226 	buf = fbufalloc();
227 	mod = FALSE;
228 	while(log->nc > 0){
229 		up = log->nc-Buflogsize;
230 		bufread(log, up, (Rune*)&b, Buflogsize);
231 		switch(b.type){
232 		default:
233 			fprint(2, "elogapply: 0x%ux\n", b.type);
234 			abort();
235 			break;
236 
237 		case Replace:
238 			if(!mod){
239 				mod = TRUE;
240 				filemark(f);
241 			}
242 			textdelete(f->curtext, b.q0, b.q0+b.nd, TRUE);
243 			up -= b.nr;
244 			for(i=0; i<b.nr; i+=n){
245 				n = b.nr - i;
246 				if(n > RBUFSIZE)
247 					n = RBUFSIZE;
248 				bufread(log, up+i, buf, n);
249 				textinsert(f->curtext, b.q0+i, buf, n, TRUE);
250 			}
251 			f->curtext->q0 = b.q0;
252 			f->curtext->q1 = b.q0+b.nr;
253 			break;
254 
255 		case Delete:
256 			if(!mod){
257 				mod = TRUE;
258 				filemark(f);
259 			}
260 			textdelete(f->curtext, b.q0, b.q0+b.nd, TRUE);
261 			f->curtext->q0 = b.q0;
262 			f->curtext->q1 = b.q0;
263 			break;
264 
265 		case Insert:
266 			if(!mod){
267 				mod = TRUE;
268 				filemark(f);
269 			}
270 			up -= b.nr;
271 			for(i=0; i<b.nr; i+=n){
272 				n = b.nr - i;
273 				if(n > RBUFSIZE)
274 					n = RBUFSIZE;
275 				bufread(log, up+i, buf, n);
276 				textinsert(f->curtext, b.q0+i, buf, n, TRUE);
277 			}
278 			f->curtext->q0 = b.q0;
279 			f->curtext->q1 = b.q0+b.nr;
280 			break;
281 
282 /*		case Filename:
283 			f->seq = u.seq;
284 			fileunsetname(f, epsilon);
285 			f->mod = u.mod;
286 			up -= u.n;
287 			free(f->name);
288 			if(u.n == 0)
289 				f->name = nil;
290 			else
291 				f->name = runemalloc(u.n);
292 			bufread(delta, up, f->name, u.n);
293 			f->nname = u.n;
294 			break;
295 */
296 		}
297 		bufdelete(log, up, log->nc);
298 	}
299 	fbuffree(buf);
300 	elogterm(f);
301 }
302