1 /*
2  * interactive diff, inspired/stolen from
3  * kernighan and pike, _unix programming environment_.
4  */
5 
6 #include <u.h>
7 #include <libc.h>
8 #include <bio.h>
9 
10 int diffbflag;
11 int diffwflag;
12 
13 void copy(Biobuf*, char*, Biobuf*, char*);
14 void idiff(Biobuf*, char*, Biobuf*, char*, Biobuf*, char*, Biobuf*, char*);
15 int opentemp(char*, int, long);
16 void rundiff(char*, char*, int);
17 
18 void
19 usage(void)
20 {
21 	fprint(2, "usage: idiff [-bw] file1 file2\n");
22 	exits("usage");
23 }
24 
25 void
26 main(int argc, char **argv)
27 {
28 	int fd, ofd;
29 	char diffout[40], idiffout[40];
30 	Biobuf *b1, *b2, bdiff, bout, bstdout;
31 	Dir *d;
32 
33 	ARGBEGIN{
34 	default:
35 		usage();
36 	case 'b':
37 		diffbflag++;
38 		break;
39 	case 'w':
40 		diffwflag++;
41 		break;
42 	}ARGEND
43 
44 	if(argc != 2)
45 		usage();
46 
47 	if((d = dirstat(argv[0])) == nil)
48 		sysfatal("stat %s: %r", argv[0]);
49 	if(d->mode&DMDIR)
50 		sysfatal("%s is a directory", argv[0]);
51 	free(d);
52 	if((d = dirstat(argv[1])) == nil)
53 		sysfatal("stat %s: %r", argv[1]);
54 	if(d->mode&DMDIR)
55 		sysfatal("%s is a directory", argv[1]);
56 	free(d);
57 
58 	if((b1 = Bopen(argv[0], OREAD)) == nil)
59 		sysfatal("open %s: %r", argv[0]);
60 	if((b2 = Bopen(argv[1], OREAD)) == nil)
61 		sysfatal("open %s: %r", argv[1]);
62 
63 	strcpy(diffout, "/tmp/idiff.XXXXXX");
64 	fd = opentemp(diffout, ORDWR|ORCLOSE, 0);
65 	strcpy(idiffout, "/tmp/idiff.XXXXXX");
66 	ofd = opentemp(idiffout, ORDWR|ORCLOSE, 0);
67 	rundiff(argv[0], argv[1], fd);
68 	seek(fd, 0, 0);
69 	Binit(&bdiff, fd, OREAD);
70 	Binit(&bout, ofd, OWRITE);
71 	idiff(b1, argv[0], b2, argv[1], &bdiff, diffout, &bout, idiffout);
72 	Bterm(&bdiff);
73 	Bflush(&bout);
74 	seek(ofd, 0, 0);
75 	Binit(&bout, ofd, OREAD);
76 	Binit(&bstdout, 1, OWRITE);
77 	copy(&bout, idiffout, &bstdout, "<stdout>");
78 	exits(nil);
79 }
80 
81 int
82 opentemp(char *template, int mode, long perm)
83 {
84 	int fd;
85 	Dir d;
86 
87 	fd = mkstemp(template);
88 	if(fd < 0)
89 		sysfatal("could not create temporary file");
90 	nulldir(&d);
91 	d.mode = perm;
92 	dirfwstat(fd, &d);
93 
94 	return fd;
95 }
96 
97 void
98 rundiff(char *arg1, char *arg2, int outfd)
99 {
100 	char *arg[10], *p;
101 	int narg, pid;
102 	Waitmsg *w;
103 
104 	narg = 0;
105 	arg[narg++] = "/bin/diff";
106 	arg[narg++] = "-n";
107 	if(diffbflag)
108 		arg[narg++] = "-b";
109 	if(diffwflag)
110 		arg[narg++] = "-w";
111 	arg[narg++] = arg1;
112 	arg[narg++] = arg2;
113 	arg[narg] = nil;
114 
115 	switch(pid = fork()){
116 	case -1:
117 		sysfatal("fork: %r");
118 
119 	case 0:
120 		dup(outfd, 1);
121 		close(0);
122 		exec("/bin/diff", arg);
123 		sysfatal("exec: %r");
124 
125 	default:
126 		w = wait();
127 		if(w==nil)
128 			sysfatal("wait: %r");
129 		if(w->pid != pid)
130 			sysfatal("wait got unexpected pid %d", w->pid);
131 		if((p = strchr(w->msg, ':')) && strcmp(p, ": some") != 0)
132 			sysfatal("%s", w->msg);
133 		free(w);
134 	}
135 }
136 
137 void
138 runcmd(char *cmd)
139 {
140 	char *arg[10];
141 	int narg, pid, wpid;
142 
143 	narg = 0;
144 	arg[narg++] = "/bin/rc";
145 	arg[narg++] = "-c";
146 	arg[narg++] = cmd;
147 	arg[narg] = nil;
148 
149 	switch(pid = fork()){
150 	case -1:
151 		sysfatal("fork: %r");
152 
153 	case 0:
154 		exec("/bin/rc", arg);
155 		sysfatal("exec: %r");
156 
157 	default:
158 		wpid = waitpid();
159 		if(wpid < 0)
160 			sysfatal("wait: %r");
161 		if(wpid != pid)
162 			sysfatal("wait got unexpected pid %d", wpid);
163 	}
164 }
165 
166 void
167 parse(char *s, int *pfrom1, int *pto1, int *pcmd, int *pfrom2, int *pto2)
168 {
169 	*pfrom1 = *pto1 = *pfrom2 = *pto2 = 0;
170 
171 	s = strchr(s, ':');
172 	if(s == nil)
173 		sysfatal("bad diff output0");
174 	s++;
175 	*pfrom1 = strtol(s, &s, 10);
176 	if(*s == ','){
177 		s++;
178 		*pto1 = strtol(s, &s, 10);
179 	}else
180 		*pto1 = *pfrom1;
181 	if(*s++ != ' ')
182 		sysfatal("bad diff output1");
183 	*pcmd = *s++;
184 	if(*s++ != ' ')
185 		sysfatal("bad diff output2");
186 	s = strchr(s, ':');
187 	if(s == nil)
188 		sysfatal("bad diff output3");
189 	s++;
190 	*pfrom2 = strtol(s, &s, 10);
191 	if(*s == ','){
192 		s++;
193 		*pto2 = strtol(s, &s, 10);
194 	}else
195 		*pto2 = *pfrom2;
196 }
197 
198 void
199 skiplines(Biobuf *b, char *name, int n)
200 {
201 	int i;
202 
203 	for(i=0; i<n; i++){
204 		while(Brdline(b, '\n')==nil){
205 			if(Blinelen(b) <= 0)
206 				sysfatal("early end of file on %s", name);
207 			Bseek(b, Blinelen(b), 1);
208 		}
209 	}
210 }
211 
212 void
213 copylines(Biobuf *bin, char *nin, Biobuf *bout, char *nout, int n)
214 {
215 	char buf[4096], *p;
216 	int i, m;
217 
218 	for(i=0; i<n; i++){
219 		while((p=Brdline(bin, '\n'))==nil){
220 			if(Blinelen(bin) <= 0)
221 				sysfatal("early end of file on %s", nin);
222 			m = Blinelen(bin);
223 			if(m > sizeof buf)
224 				m = sizeof buf;
225 			m = Bread(bin, buf, m);
226 			if(Bwrite(bout, buf, m) != m)
227 				sysfatal("error writing %s: %r", nout);
228 		}
229 		if(Bwrite(bout, p, Blinelen(bin)) != Blinelen(bin))
230 			sysfatal("error writing %s: %r", nout);
231 	}
232 }
233 
234 void
235 copy(Biobuf *bin, char *nin, Biobuf *bout, char *nout)
236 {
237 	char buf[4096];
238 	int m;
239 
240 	USED(nin);
241 	while((m = Bread(bin, buf, sizeof buf)) > 0)
242 		if(Bwrite(bout, buf, m) != m)
243 			sysfatal("error writing %s: %r", nout);
244 }
245 
246 void
247 idiff(Biobuf *b1, char *name1, Biobuf *b2, char *name2, Biobuf *bdiff, char *namediff, Biobuf *bout, char *nameout)
248 {
249 	char buf[256], *p;
250 	int interactive, defaultanswer, cmd, diffoffset;
251 	int n, from1, to1, from2, to2, nf1, nf2;
252 	Biobuf berr;
253 
254 	nf1 = 1;
255 	nf2 = 1;
256 	interactive = 1;
257 	defaultanswer = 0;
258 	Binit(&berr, 2, OWRITE);
259 	while(diffoffset = Boffset(bdiff), p = Brdline(bdiff, '\n')){
260 		p[Blinelen(bdiff)-1] = '\0';
261 		parse(p, &from1, &to1, &cmd, &from2, &to2);
262 		p[Blinelen(bdiff)-1] = '\n';
263 		n = to1-from1 + to2-from2 + 1;	/* #lines from diff */
264 		if(cmd == 'c')
265 			n += 2;
266 		else if(cmd == 'a')
267 			from1++;
268 		else if(cmd == 'd')
269 			from2++;
270 		to1++;	/* make half-open intervals */
271 		to2++;
272 		if(interactive){
273 			p[Blinelen(bdiff)-1] = '\0';
274 			fprint(2, "%s\n", p);
275 			p[Blinelen(bdiff)-1] = '\n';
276 			copylines(bdiff, namediff, &berr, "<stderr>", n);
277 			Bflush(&berr);
278 		}else
279 			skiplines(bdiff, namediff, n);
280 		do{
281 			if(interactive){
282 				fprint(2, "? ");
283 				memset(buf, 0, sizeof buf);
284 				if(read(0, buf, sizeof buf - 1) < 0)
285 					sysfatal("read console: %r");
286 			}else
287 				buf[0] = defaultanswer;
288 
289 			switch(buf[0]){
290 			case '>':
291 				copylines(b1, name1, bout, nameout, from1-nf1);
292 				skiplines(b1, name1, to1-from1);
293 				skiplines(b2, name2, from2-nf2);
294 				copylines(b2, name2, bout, nameout, to2-from2);
295 				break;
296 			case '<':
297 				copylines(b1, name1, bout, nameout, to1-nf1);
298 				skiplines(b2, name2, to2-nf2);
299 				break;
300 			case '=':
301 				copylines(b1, name1, bout, nameout, from1-nf1);
302 				skiplines(b1, name1, to1-from1);
303 				skiplines(b2, name2, to2-nf2);
304 				if(Bseek(bdiff, diffoffset, 0) != diffoffset)
305 					sysfatal("seek in diff output: %r");
306 				copylines(bdiff, namediff, bout, nameout, n+1);
307 				break;
308 			case '!':
309 				runcmd(buf+1);
310 				break;
311 			case 'q':
312 				if(buf[1]=='<' || buf[1]=='>' || buf[1]=='='){
313 					interactive = 0;
314 					defaultanswer = buf[1];
315 				}else
316 					fprint(2, "must be q<, q>, or q=\n");
317 				break;
318 			default:
319 				fprint(2, "expect: <, >, =, q<, q>, q=, !cmd\n");
320 				break;
321 			}
322 		}while(buf[0] != '<' && buf[0] != '>' && buf[0] != '=');
323 		nf1 = to1;
324 		nf2 = to2;
325 	}
326 	copy(b1, name1, bout, nameout);
327 }