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 void rundiff(char*, char*, int);
16 
17 void
18 usage(void)
19 {
20 	fprint(2, "usage: idiff [-bw] file1 file2\n");
21 	exits("usage");
22 }
23 
24 void
25 main(int argc, char **argv)
26 {
27 	int fd, ofd;
28 	char diffout[40], idiffout[40];
29 	Biobuf *b1, *b2, bdiff, bout, bstdout;
30 	Dir *d;
31 
32 	ARGBEGIN{
33 	default:
34 		usage();
35 	case 'b':
36 		diffbflag++;
37 		break;
38 	case 'w':
39 		diffwflag++;
40 		break;
41 	}ARGEND
42 
43 	if(argc != 2)
44 		usage();
45 
46 	if((d = dirstat(argv[0])) == nil)
47 		sysfatal("stat %s: %r", argv[0]);
48 	if(d->mode&DMDIR)
49 		sysfatal("%s is a directory", argv[0]);
50 	free(d);
51 	if((d = dirstat(argv[1])) == nil)
52 		sysfatal("stat %s: %r", argv[1]);
53 	if(d->mode&DMDIR)
54 		sysfatal("%s is a directory", argv[1]);
55 	free(d);
56 
57 	if((b1 = Bopen(argv[0], OREAD)) == nil)
58 		sysfatal("open %s: %r", argv[0]);
59 	if((b2 = Bopen(argv[1], OREAD)) == nil)
60 		sysfatal("open %s: %r", argv[1]);
61 
62 	strcpy(diffout, "/tmp/idiff.XXXXXX");
63 	fd = opentemp(diffout, ORDWR|ORCLOSE);
64 	strcpy(idiffout, "/tmp/idiff.XXXXXX");
65 	ofd = opentemp(idiffout, ORDWR|ORCLOSE);
66 	rundiff(argv[0], argv[1], fd);
67 	seek(fd, 0, 0);
68 	Binit(&bdiff, fd, OREAD);
69 	Binit(&bout, ofd, OWRITE);
70 	idiff(b1, argv[0], b2, argv[1], &bdiff, diffout, &bout, idiffout);
71 	Bterm(&bdiff);
72 	Bflush(&bout);
73 	seek(ofd, 0, 0);
74 	Binit(&bout, ofd, OREAD);
75 	Binit(&bstdout, 1, OWRITE);
76 	copy(&bout, idiffout, &bstdout, "<stdout>");
77 	exits(nil);
78 }
79 
80 void
81 rundiff(char *arg1, char *arg2, int outfd)
82 {
83 	char *arg[10], *p;
84 	int narg, pid;
85 	Waitmsg *w;
86 
87 	narg = 0;
88 	arg[narg++] = "9";
89 	arg[narg++] = "diff";
90 	arg[narg++] = "-n";
91 	if(diffbflag)
92 		arg[narg++] = "-b";
93 	if(diffwflag)
94 		arg[narg++] = "-w";
95 	arg[narg++] = arg1;
96 	arg[narg++] = arg2;
97 	arg[narg] = nil;
98 
99 	switch(pid = fork()){
100 	case -1:
101 		sysfatal("fork: %r");
102 
103 	case 0:
104 		dup(outfd, 1);
105 		close(0);
106 		exec("9", arg);
107 		sysfatal("exec: %r");
108 
109 	default:
110 		w = wait();
111 		if(w==nil)
112 			sysfatal("wait: %r");
113 		if(w->pid != pid)
114 			sysfatal("wait got unexpected pid %d", w->pid);
115 		if((p = strchr(w->msg, ':')) && strcmp(p, ": some") != 0)
116 			sysfatal("%s", w->msg);
117 		free(w);
118 	}
119 }
120 
121 void
122 runcmd(char *cmd)
123 {
124 	char *arg[10];
125 	int narg, pid, wpid;
126 
127 	narg = 0;
128 	arg[narg++] = "rc";
129 	arg[narg++] = "-c";
130 	arg[narg++] = cmd;
131 	arg[narg] = nil;
132 
133 	switch(pid = fork()){
134 	case -1:
135 		sysfatal("fork: %r");
136 
137 	case 0:
138 		exec("rc", arg);
139 		sysfatal("exec: %r");
140 
141 	default:
142 		wpid = waitpid();
143 		if(wpid < 0)
144 			sysfatal("wait: %r");
145 		if(wpid != pid)
146 			sysfatal("wait got unexpected pid %d", wpid);
147 	}
148 }
149 
150 void
151 parse(char *s, int *pfrom1, int *pto1, int *pcmd, int *pfrom2, int *pto2)
152 {
153 	*pfrom1 = *pto1 = *pfrom2 = *pto2 = 0;
154 
155 	s = strchr(s, ':');
156 	if(s == nil)
157 		sysfatal("bad diff output0");
158 	s++;
159 	*pfrom1 = strtol(s, &s, 10);
160 	if(*s == ','){
161 		s++;
162 		*pto1 = strtol(s, &s, 10);
163 	}else
164 		*pto1 = *pfrom1;
165 	if(*s++ != ' ')
166 		sysfatal("bad diff output1");
167 	*pcmd = *s++;
168 	if(*s++ != ' ')
169 		sysfatal("bad diff output2");
170 	s = strchr(s, ':');
171 	if(s == nil)
172 		sysfatal("bad diff output3");
173 	s++;
174 	*pfrom2 = strtol(s, &s, 10);
175 	if(*s == ','){
176 		s++;
177 		*pto2 = strtol(s, &s, 10);
178 	}else
179 		*pto2 = *pfrom2;
180 }
181 
182 void
183 skiplines(Biobuf *b, char *name, int n)
184 {
185 	int i;
186 
187 	for(i=0; i<n; i++){
188 		while(Brdline(b, '\n')==nil){
189 			if(Blinelen(b) <= 0)
190 				sysfatal("early end of file on %s", name);
191 			Bseek(b, Blinelen(b), 1);
192 		}
193 	}
194 }
195 
196 void
197 copylines(Biobuf *bin, char *nin, Biobuf *bout, char *nout, int n)
198 {
199 	char buf[4096], *p;
200 	int i, m;
201 
202 	for(i=0; i<n; i++){
203 		while((p=Brdline(bin, '\n'))==nil){
204 			if(Blinelen(bin) <= 0)
205 				sysfatal("early end of file on %s", nin);
206 			m = Blinelen(bin);
207 			if(m > sizeof buf)
208 				m = sizeof buf;
209 			m = Bread(bin, buf, m);
210 			if(Bwrite(bout, buf, m) != m)
211 				sysfatal("error writing %s: %r", nout);
212 		}
213 		if(Bwrite(bout, p, Blinelen(bin)) != Blinelen(bin))
214 			sysfatal("error writing %s: %r", nout);
215 	}
216 }
217 
218 void
219 copy(Biobuf *bin, char *nin, Biobuf *bout, char *nout)
220 {
221 	char buf[4096];
222 	int m;
223 
224 	USED(nin);
225 	while((m = Bread(bin, buf, sizeof buf)) > 0)
226 		if(Bwrite(bout, buf, m) != m)
227 			sysfatal("error writing %s: %r", nout);
228 }
229 
230 void
231 idiff(Biobuf *b1, char *name1, Biobuf *b2, char *name2, Biobuf *bdiff, char *namediff, Biobuf *bout, char *nameout)
232 {
233 	char buf[256], *p;
234 	int interactive, defaultanswer, cmd, diffoffset;
235 	int n, from1, to1, from2, to2, nf1, nf2;
236 	Biobuf berr;
237 
238 	nf1 = 1;
239 	nf2 = 1;
240 	interactive = 1;
241 	defaultanswer = 0;
242 	Binit(&berr, 2, OWRITE);
243 	while(diffoffset = Boffset(bdiff), p = Brdline(bdiff, '\n')){
244 		p[Blinelen(bdiff)-1] = '\0';
245 		parse(p, &from1, &to1, &cmd, &from2, &to2);
246 		p[Blinelen(bdiff)-1] = '\n';
247 		n = to1-from1 + to2-from2 + 1;	/* #lines from diff */
248 		if(cmd == 'c')
249 			n += 2;
250 		else if(cmd == 'a')
251 			from1++;
252 		else if(cmd == 'd')
253 			from2++;
254 		to1++;	/* make half-open intervals */
255 		to2++;
256 		if(interactive){
257 			p[Blinelen(bdiff)-1] = '\0';
258 			fprint(2, "%s\n", p);
259 			p[Blinelen(bdiff)-1] = '\n';
260 			copylines(bdiff, namediff, &berr, "<stderr>", n);
261 			Bflush(&berr);
262 		}else
263 			skiplines(bdiff, namediff, n);
264 		do{
265 			if(interactive){
266 				fprint(2, "? ");
267 				memset(buf, 0, sizeof buf);
268 				if(read(0, buf, sizeof buf - 1) < 0)
269 					sysfatal("read console: %r");
270 			}else
271 				buf[0] = defaultanswer;
272 
273 			switch(buf[0]){
274 			case '>':
275 				copylines(b1, name1, bout, nameout, from1-nf1);
276 				skiplines(b1, name1, to1-from1);
277 				skiplines(b2, name2, from2-nf2);
278 				copylines(b2, name2, bout, nameout, to2-from2);
279 				break;
280 			case '<':
281 				copylines(b1, name1, bout, nameout, to1-nf1);
282 				skiplines(b2, name2, to2-nf2);
283 				break;
284 			case '=':
285 				copylines(b1, name1, bout, nameout, from1-nf1);
286 				skiplines(b1, name1, to1-from1);
287 				skiplines(b2, name2, to2-nf2);
288 				if(Bseek(bdiff, diffoffset, 0) != diffoffset)
289 					sysfatal("seek in diff output: %r");
290 				copylines(bdiff, namediff, bout, nameout, n+1);
291 				break;
292 			case '!':
293 				runcmd(buf+1);
294 				break;
295 			case 'q':
296 				if(buf[1]=='<' || buf[1]=='>' || buf[1]=='='){
297 					interactive = 0;
298 					defaultanswer = buf[1];
299 				}else
300 					fprint(2, "must be q<, q>, or q=\n");
301 				break;
302 			default:
303 				fprint(2, "expect: <, >, =, q<, q>, q=, !cmd\n");
304 				break;
305 			}
306 		}while(buf[0] != '<' && buf[0] != '>' && buf[0] != '=');
307 		nf1 = to1;
308 		nf2 = to2;
309 	}
310 	copy(b1, name1, bout, nameout);
311 }