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++] = "diff";
108 	arg[narg++] = "-n";
109 	if(diffbflag)
110 		arg[narg++] = "-b";
111 	if(diffwflag)
112 		arg[narg++] = "-w";
113 	arg[narg++] = arg1;
114 	arg[narg++] = arg2;
115 	arg[narg] = nil;
116 
117 	switch(pid = fork()){
118 	case -1:
119 		sysfatal("fork: %r");
120 
121 	case 0:
122 		dup(outfd, 1);
123 		close(0);
124 		exec("diff", arg);
125 		sysfatal("exec: %r");
126 
127 	default:
128 		w = wait();
129 		if(w==nil)
130 			sysfatal("wait: %r");
131 		if(w->pid != pid)
132 			sysfatal("wait got unexpected pid %d", w->pid);
133 		if((p = strchr(w->msg, ':')) && strcmp(p, ": some") != 0)
134 			sysfatal("%s", w->msg);
135 		free(w);
136 	}
137 }
138 
139 void
140 runcmd(char *cmd)
141 {
142 	char *arg[10];
143 	int narg, pid, wpid;
144 
145 	narg = 0;
146 	arg[narg++] = "rc";
147 	arg[narg++] = "-c";
148 	arg[narg++] = cmd;
149 	arg[narg] = nil;
150 
151 	switch(pid = fork()){
152 	case -1:
153 		sysfatal("fork: %r");
154 
155 	case 0:
156 		exec("rc", arg);
157 		sysfatal("exec: %r");
158 
159 	default:
160 		wpid = waitpid();
161 		if(wpid < 0)
162 			sysfatal("wait: %r");
163 		if(wpid != pid)
164 			sysfatal("wait got unexpected pid %d", wpid);
165 	}
166 }
167 
168 void
169 parse(char *s, int *pfrom1, int *pto1, int *pcmd, int *pfrom2, int *pto2)
170 {
171 	*pfrom1 = *pto1 = *pfrom2 = *pto2 = 0;
172 
173 	s = strchr(s, ':');
174 	if(s == nil)
175 		sysfatal("bad diff output0");
176 	s++;
177 	*pfrom1 = strtol(s, &s, 10);
178 	if(*s == ','){
179 		s++;
180 		*pto1 = strtol(s, &s, 10);
181 	}else
182 		*pto1 = *pfrom1;
183 	if(*s++ != ' ')
184 		sysfatal("bad diff output1");
185 	*pcmd = *s++;
186 	if(*s++ != ' ')
187 		sysfatal("bad diff output2");
188 	s = strchr(s, ':');
189 	if(s == nil)
190 		sysfatal("bad diff output3");
191 	s++;
192 	*pfrom2 = strtol(s, &s, 10);
193 	if(*s == ','){
194 		s++;
195 		*pto2 = strtol(s, &s, 10);
196 	}else
197 		*pto2 = *pfrom2;
198 }
199 
200 void
201 skiplines(Biobuf *b, char *name, int n)
202 {
203 	int i;
204 
205 	for(i=0; i<n; i++){
206 		while(Brdline(b, '\n')==nil){
207 			if(Blinelen(b) <= 0)
208 				sysfatal("early end of file on %s", name);
209 			Bseek(b, Blinelen(b), 1);
210 		}
211 	}
212 }
213 
214 void
215 copylines(Biobuf *bin, char *nin, Biobuf *bout, char *nout, int n)
216 {
217 	char buf[4096], *p;
218 	int i, m;
219 
220 	for(i=0; i<n; i++){
221 		while((p=Brdline(bin, '\n'))==nil){
222 			if(Blinelen(bin) <= 0)
223 				sysfatal("early end of file on %s", nin);
224 			m = Blinelen(bin);
225 			if(m > sizeof buf)
226 				m = sizeof buf;
227 			m = Bread(bin, buf, m);
228 			if(Bwrite(bout, buf, m) != m)
229 				sysfatal("error writing %s: %r", nout);
230 		}
231 		if(Bwrite(bout, p, Blinelen(bin)) != Blinelen(bin))
232 			sysfatal("error writing %s: %r", nout);
233 	}
234 }
235 
236 void
237 copy(Biobuf *bin, char *nin, Biobuf *bout, char *nout)
238 {
239 	char buf[4096];
240 	int m;
241 
242 	USED(nin);
243 	while((m = Bread(bin, buf, sizeof buf)) > 0)
244 		if(Bwrite(bout, buf, m) != m)
245 			sysfatal("error writing %s: %r", nout);
246 }
247 
248 void
249 idiff(Biobuf *b1, char *name1, Biobuf *b2, char *name2, Biobuf *bdiff, char *namediff, Biobuf *bout, char *nameout)
250 {
251 	char buf[256], *p;
252 	int interactive, defaultanswer, cmd, diffoffset;
253 	int n, from1, to1, from2, to2, nf1, nf2;
254 	Biobuf berr;
255 
256 	nf1 = 1;
257 	nf2 = 1;
258 	interactive = 1;
259 	defaultanswer = 0;
260 	Binit(&berr, 2, OWRITE);
261 	while(diffoffset = Boffset(bdiff), p = Brdline(bdiff, '\n')){
262 		p[Blinelen(bdiff)-1] = '\0';
263 		parse(p, &from1, &to1, &cmd, &from2, &to2);
264 		p[Blinelen(bdiff)-1] = '\n';
265 		n = to1-from1 + to2-from2 + 1;	/* #lines from diff */
266 		if(cmd == 'c')
267 			n += 2;
268 		else if(cmd == 'a')
269 			from1++;
270 		else if(cmd == 'd')
271 			from2++;
272 		to1++;	/* make half-open intervals */
273 		to2++;
274 		if(interactive){
275 			p[Blinelen(bdiff)-1] = '\0';
276 			fprint(2, "%s\n", p);
277 			p[Blinelen(bdiff)-1] = '\n';
278 			copylines(bdiff, namediff, &berr, "<stderr>", n);
279 			Bflush(&berr);
280 		}else
281 			skiplines(bdiff, namediff, n);
282 		do{
283 			if(interactive){
284 				fprint(2, "? ");
285 				memset(buf, 0, sizeof buf);
286 				if(read(0, buf, sizeof buf - 1) < 0)
287 					sysfatal("read console: %r");
288 			}else
289 				buf[0] = defaultanswer;
290 
291 			switch(buf[0]){
292 			case '>':
293 				copylines(b1, name1, bout, nameout, from1-nf1);
294 				skiplines(b1, name1, to1-from1);
295 				skiplines(b2, name2, from2-nf2);
296 				copylines(b2, name2, bout, nameout, to2-from2);
297 				break;
298 			case '<':
299 				copylines(b1, name1, bout, nameout, to1-nf1);
300 				skiplines(b2, name2, to2-nf2);
301 				break;
302 			case '=':
303 				copylines(b1, name1, bout, nameout, from1-nf1);
304 				skiplines(b1, name1, to1-from1);
305 				skiplines(b2, name2, to2-nf2);
306 				if(Bseek(bdiff, diffoffset, 0) != diffoffset)
307 					sysfatal("seek in diff output: %r");
308 				copylines(bdiff, namediff, bout, nameout, n+1);
309 				break;
310 			case '!':
311 				runcmd(buf+1);
312 				break;
313 			case 'q':
314 				if(buf[1]=='<' || buf[1]=='>' || buf[1]=='='){
315 					interactive = 0;
316 					defaultanswer = buf[1];
317 				}else
318 					fprint(2, "must be q<, q>, or q=\n");
319 				break;
320 			default:
321 				fprint(2, "expect: <, >, =, q<, q>, q=, !cmd\n");
322 				break;
323 			}
324 		}while(buf[0] != '<' && buf[0] != '>' && buf[0] != '=');
325 		nf1 = to1;
326 		nf2 = to2;
327 	}
328 	copy(b1, name1, bout, nameout);
329 }