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 #define opentemp idiffopentemp
11 
12 int diffbflag;
13 int diffwflag;
14 
15 void copy(Biobuf*, char*, Biobuf*, char*);
16 void idiff(Biobuf*, char*, Biobuf*, char*, Biobuf*, char*, Biobuf*, char*);
17 int opentemp(char*, int, long);
18 void rundiff(char*, char*, int);
19 
20 void
21 usage(void)
22 {
23 	fprint(2, "usage: idiff [-bw] file1 file2\n");
24 	exits("usage");
25 }
26 
27 void
28 main(int argc, char **argv)
29 {
30 	int fd, ofd;
31 	char diffout[40], idiffout[40];
32 	Biobuf *b1, *b2, bdiff, bout, bstdout;
33 	Dir *d;
34 
35 	ARGBEGIN{
36 	default:
37 		usage();
38 	case 'b':
39 		diffbflag++;
40 		break;
41 	case 'w':
42 		diffwflag++;
43 		break;
44 	}ARGEND
45 
46 	if(argc != 2)
47 		usage();
48 
49 	if((d = dirstat(argv[0])) == nil)
50 		sysfatal("stat %s: %r", argv[0]);
51 	if(d->mode&DMDIR)
52 		sysfatal("%s is a directory", argv[0]);
53 	free(d);
54 	if((d = dirstat(argv[1])) == nil)
55 		sysfatal("stat %s: %r", argv[1]);
56 	if(d->mode&DMDIR)
57 		sysfatal("%s is a directory", argv[1]);
58 	free(d);
59 
60 	if((b1 = Bopen(argv[0], OREAD)) == nil)
61 		sysfatal("open %s: %r", argv[0]);
62 	if((b2 = Bopen(argv[1], OREAD)) == nil)
63 		sysfatal("open %s: %r", argv[1]);
64 
65 	strcpy(diffout, "/tmp/idiff.XXXXXX");
66 	fd = opentemp(diffout, ORDWR|ORCLOSE, 0);
67 	strcpy(idiffout, "/tmp/idiff.XXXXXX");
68 	ofd = opentemp(idiffout, ORDWR|ORCLOSE, 0);
69 	rundiff(argv[0], argv[1], fd);
70 	seek(fd, 0, 0);
71 	Binit(&bdiff, fd, OREAD);
72 	Binit(&bout, ofd, OWRITE);
73 	idiff(b1, argv[0], b2, argv[1], &bdiff, diffout, &bout, idiffout);
74 	Bterm(&bdiff);
75 	Bflush(&bout);
76 	seek(ofd, 0, 0);
77 	Binit(&bout, ofd, OREAD);
78 	Binit(&bstdout, 1, OWRITE);
79 	copy(&bout, idiffout, &bstdout, "<stdout>");
80 	exits(nil);
81 }
82 
83 int
84 opentemp(char *template, int mode, long perm)
85 {
86 	int fd;
87 	Dir d;
88 
89 	fd = mkstemp(template);
90 	if(fd < 0)
91 		sysfatal("could not create temporary file");
92 	nulldir(&d);
93 	d.mode = perm;
94 	dirfwstat(fd, &d);
95 
96 	return fd;
97 }
98 
99 void
100 rundiff(char *arg1, char *arg2, int outfd)
101 {
102 	char *arg[10], *p;
103 	int narg, pid;
104 	Waitmsg *w;
105 
106 	narg = 0;
107 	arg[narg++] = "9";
108 	arg[narg++] = "diff";
109 	arg[narg++] = "-n";
110 	if(diffbflag)
111 		arg[narg++] = "-b";
112 	if(diffwflag)
113 		arg[narg++] = "-w";
114 	arg[narg++] = arg1;
115 	arg[narg++] = arg2;
116 	arg[narg] = nil;
117 
118 	switch(pid = fork()){
119 	case -1:
120 		sysfatal("fork: %r");
121 
122 	case 0:
123 		dup(outfd, 1);
124 		close(0);
125 		exec("9", arg);
126 		sysfatal("exec: %r");
127 
128 	default:
129 		w = wait();
130 		if(w==nil)
131 			sysfatal("wait: %r");
132 		if(w->pid != pid)
133 			sysfatal("wait got unexpected pid %d", w->pid);
134 		if((p = strchr(w->msg, ':')) && strcmp(p, ": some") != 0)
135 			sysfatal("%s", w->msg);
136 		free(w);
137 	}
138 }
139 
140 void
141 runcmd(char *cmd)
142 {
143 	char *arg[10];
144 	int narg, pid, wpid;
145 
146 	narg = 0;
147 	arg[narg++] = "rc";
148 	arg[narg++] = "-c";
149 	arg[narg++] = cmd;
150 	arg[narg] = nil;
151 
152 	switch(pid = fork()){
153 	case -1:
154 		sysfatal("fork: %r");
155 
156 	case 0:
157 		exec("rc", arg);
158 		sysfatal("exec: %r");
159 
160 	default:
161 		wpid = waitpid();
162 		if(wpid < 0)
163 			sysfatal("wait: %r");
164 		if(wpid != pid)
165 			sysfatal("wait got unexpected pid %d", wpid);
166 	}
167 }
168 
169 void
170 parse(char *s, int *pfrom1, int *pto1, int *pcmd, int *pfrom2, int *pto2)
171 {
172 	*pfrom1 = *pto1 = *pfrom2 = *pto2 = 0;
173 
174 	s = strchr(s, ':');
175 	if(s == nil)
176 		sysfatal("bad diff output0");
177 	s++;
178 	*pfrom1 = strtol(s, &s, 10);
179 	if(*s == ','){
180 		s++;
181 		*pto1 = strtol(s, &s, 10);
182 	}else
183 		*pto1 = *pfrom1;
184 	if(*s++ != ' ')
185 		sysfatal("bad diff output1");
186 	*pcmd = *s++;
187 	if(*s++ != ' ')
188 		sysfatal("bad diff output2");
189 	s = strchr(s, ':');
190 	if(s == nil)
191 		sysfatal("bad diff output3");
192 	s++;
193 	*pfrom2 = strtol(s, &s, 10);
194 	if(*s == ','){
195 		s++;
196 		*pto2 = strtol(s, &s, 10);
197 	}else
198 		*pto2 = *pfrom2;
199 }
200 
201 void
202 skiplines(Biobuf *b, char *name, int n)
203 {
204 	int i;
205 
206 	for(i=0; i<n; i++){
207 		while(Brdline(b, '\n')==nil){
208 			if(Blinelen(b) <= 0)
209 				sysfatal("early end of file on %s", name);
210 			Bseek(b, Blinelen(b), 1);
211 		}
212 	}
213 }
214 
215 void
216 copylines(Biobuf *bin, char *nin, Biobuf *bout, char *nout, int n)
217 {
218 	char buf[4096], *p;
219 	int i, m;
220 
221 	for(i=0; i<n; i++){
222 		while((p=Brdline(bin, '\n'))==nil){
223 			if(Blinelen(bin) <= 0)
224 				sysfatal("early end of file on %s", nin);
225 			m = Blinelen(bin);
226 			if(m > sizeof buf)
227 				m = sizeof buf;
228 			m = Bread(bin, buf, m);
229 			if(Bwrite(bout, buf, m) != m)
230 				sysfatal("error writing %s: %r", nout);
231 		}
232 		if(Bwrite(bout, p, Blinelen(bin)) != Blinelen(bin))
233 			sysfatal("error writing %s: %r", nout);
234 	}
235 }
236 
237 void
238 copy(Biobuf *bin, char *nin, Biobuf *bout, char *nout)
239 {
240 	char buf[4096];
241 	int m;
242 
243 	USED(nin);
244 	while((m = Bread(bin, buf, sizeof buf)) > 0)
245 		if(Bwrite(bout, buf, m) != m)
246 			sysfatal("error writing %s: %r", nout);
247 }
248 
249 void
250 idiff(Biobuf *b1, char *name1, Biobuf *b2, char *name2, Biobuf *bdiff, char *namediff, Biobuf *bout, char *nameout)
251 {
252 	char buf[256], *p;
253 	int interactive, defaultanswer, cmd, diffoffset;
254 	int n, from1, to1, from2, to2, nf1, nf2;
255 	Biobuf berr;
256 
257 	nf1 = 1;
258 	nf2 = 1;
259 	interactive = 1;
260 	defaultanswer = 0;
261 	Binit(&berr, 2, OWRITE);
262 	while(diffoffset = Boffset(bdiff), p = Brdline(bdiff, '\n')){
263 		p[Blinelen(bdiff)-1] = '\0';
264 		parse(p, &from1, &to1, &cmd, &from2, &to2);
265 		p[Blinelen(bdiff)-1] = '\n';
266 		n = to1-from1 + to2-from2 + 1;	/* #lines from diff */
267 		if(cmd == 'c')
268 			n += 2;
269 		else if(cmd == 'a')
270 			from1++;
271 		else if(cmd == 'd')
272 			from2++;
273 		to1++;	/* make half-open intervals */
274 		to2++;
275 		if(interactive){
276 			p[Blinelen(bdiff)-1] = '\0';
277 			fprint(2, "%s\n", p);
278 			p[Blinelen(bdiff)-1] = '\n';
279 			copylines(bdiff, namediff, &berr, "<stderr>", n);
280 			Bflush(&berr);
281 		}else
282 			skiplines(bdiff, namediff, n);
283 		do{
284 			if(interactive){
285 				fprint(2, "? ");
286 				memset(buf, 0, sizeof buf);
287 				if(read(0, buf, sizeof buf - 1) < 0)
288 					sysfatal("read console: %r");
289 			}else
290 				buf[0] = defaultanswer;
291 
292 			switch(buf[0]){
293 			case '>':
294 				copylines(b1, name1, bout, nameout, from1-nf1);
295 				skiplines(b1, name1, to1-from1);
296 				skiplines(b2, name2, from2-nf2);
297 				copylines(b2, name2, bout, nameout, to2-from2);
298 				break;
299 			case '<':
300 				copylines(b1, name1, bout, nameout, to1-nf1);
301 				skiplines(b2, name2, to2-nf2);
302 				break;
303 			case '=':
304 				copylines(b1, name1, bout, nameout, from1-nf1);
305 				skiplines(b1, name1, to1-from1);
306 				skiplines(b2, name2, to2-nf2);
307 				if(Bseek(bdiff, diffoffset, 0) != diffoffset)
308 					sysfatal("seek in diff output: %r");
309 				copylines(bdiff, namediff, bout, nameout, n+1);
310 				break;
311 			case '!':
312 				runcmd(buf+1);
313 				break;
314 			case 'q':
315 				if(buf[1]=='<' || buf[1]=='>' || buf[1]=='='){
316 					interactive = 0;
317 					defaultanswer = buf[1];
318 				}else
319 					fprint(2, "must be q<, q>, or q=\n");
320 				break;
321 			default:
322 				fprint(2, "expect: <, >, =, q<, q>, q=, !cmd\n");
323 				break;
324 			}
325 		}while(buf[0] != '<' && buf[0] != '>' && buf[0] != '=');
326 		nf1 = to1;
327 		nf2 = to2;
328 	}
329 	copy(b1, name1, bout, nameout);
330 }