src/cmd/idiff.c - plan9 - Git at Google

 /*
  * interactive diff, inspired/stolen from
  * kernighan and pike, _unix programming environment_.
  */

 #include <u.h>
 #include <libc.h>
 #include <bio.h>

 #define opentemp idiffopentemp

 int diffbflag;
 int diffwflag;

 void copy(Biobuf*, char*, Biobuf*, char*);
 void idiff(Biobuf*, char*, Biobuf*, char*, Biobuf*, char*, Biobuf*, char*);
 int opentemp(char*, int, long);
 void rundiff(char*, char*, int);

 void
 usage(void)
 {
 	fprint(2, "usage: idiff [-bw] file1 file2\n");
 	exits("usage");
 }

 void
 main(int argc, char **argv)
 {
 	int fd, ofd;
 	char diffout[40], idiffout[40];
 	Biobuf *b1, *b2, bdiff, bout, bstdout;
 	Dir *d;

 	ARGBEGIN{
 	default:
 		usage();
 	case 'b':
 		diffbflag++;
 		break;
 	case 'w':
 		diffwflag++;
 		break;
 	}ARGEND

 	if(argc != 2)
 		usage();

 	if((d = dirstat(argv[0])) == nil)
 		sysfatal("stat %s: %r", argv[0]);
 	if(d->mode&DMDIR)
 		sysfatal("%s is a directory", argv[0]);
 	free(d);
 	if((d = dirstat(argv[1])) == nil)
 		sysfatal("stat %s: %r", argv[1]);
 	if(d->mode&DMDIR)
 		sysfatal("%s is a directory", argv[1]);
 	free(d);

 	if((b1 = Bopen(argv[0], OREAD)) == nil)
 		sysfatal("open %s: %r", argv[0]);
 	if((b2 = Bopen(argv[1], OREAD)) == nil)
 		sysfatal("open %s: %r", argv[1]);

 	strcpy(diffout, "/tmp/idiff.XXXXXX");
 	fd = opentemp(diffout, ORDWR|ORCLOSE, 0);
 	strcpy(idiffout, "/tmp/idiff.XXXXXX");
 	ofd = opentemp(idiffout, ORDWR|ORCLOSE, 0);
 	rundiff(argv[0], argv[1], fd);
 	seek(fd, 0, 0);
 	Binit(&bdiff, fd, OREAD);
 	Binit(&bout, ofd, OWRITE);
 	idiff(b1, argv[0], b2, argv[1], &bdiff, diffout, &bout, idiffout);
 	Bterm(&bdiff);
 	Bflush(&bout);
 	seek(ofd, 0, 0);
 	Binit(&bout, ofd, OREAD);
 	Binit(&bstdout, 1, OWRITE);
 	copy(&bout, idiffout, &bstdout, "<stdout>");
 	exits(nil);
 }

 int
 opentemp(char *template, int mode, long perm)
 {
 	int fd;
 	Dir d;

 	fd = mkstemp(template);
 	if(fd < 0)
 		sysfatal("could not create temporary file");
 	nulldir(&d);
 	d.mode = perm;
 	dirfwstat(fd, &d);

 	return fd;
 }

 void
 rundiff(char *arg1, char *arg2, int outfd)
 {
 	char *arg[10], *p;
 	int narg, pid;
 	Waitmsg *w;

 	narg = 0;
 	arg[narg++] = "9";
 	arg[narg++] = "diff";
 	arg[narg++] = "-n";
 	if(diffbflag)
 		arg[narg++] = "-b";
 	if(diffwflag)
 		arg[narg++] = "-w";
 	arg[narg++] = arg1;
 	arg[narg++] = arg2;
 	arg[narg] = nil;

 	switch(pid = fork()){
 	case -1:
 		sysfatal("fork: %r");

 	case 0:
 		dup(outfd, 1);
 		close(0);
 		exec("9", arg);
 		sysfatal("exec: %r");

 	default:
 		w = wait();
 		if(w==nil)
 			sysfatal("wait: %r");
 		if(w->pid != pid)
 			sysfatal("wait got unexpected pid %d", w->pid);
 		if((p = strchr(w->msg, ':')) && strcmp(p, ": some") != 0)
 			sysfatal("%s", w->msg);
 		free(w);
 	}
 }

 void
 runcmd(char *cmd)
 {
 	char *arg[10];
 	int narg, pid, wpid;

 	narg = 0;
 	arg[narg++] = "rc";
 	arg[narg++] = "-c";
 	arg[narg++] = cmd;
 	arg[narg] = nil;

 	switch(pid = fork()){
 	case -1:
 		sysfatal("fork: %r");

 	case 0:
 		exec("rc", arg);
 		sysfatal("exec: %r");

 	default:
 		wpid = waitpid();
 		if(wpid < 0)
 			sysfatal("wait: %r");
 		if(wpid != pid)
 			sysfatal("wait got unexpected pid %d", wpid);
 	}
 }

 void
 parse(char *s, int *pfrom1, int *pto1, int *pcmd, int *pfrom2, int *pto2)
 {
 	*pfrom1 = *pto1 = *pfrom2 = *pto2 = 0;

 	s = strchr(s, ':');
 	if(s == nil)
 		sysfatal("bad diff output0");
 	s++;
 	*pfrom1 = strtol(s, &s, 10);
 	if(*s == ','){
 		s++;
 		*pto1 = strtol(s, &s, 10);
 	}else
 		*pto1 = *pfrom1;
 	if(*s++ != ' ')
 		sysfatal("bad diff output1");
 	*pcmd = *s++;
 	if(*s++ != ' ')
 		sysfatal("bad diff output2");
 	s = strchr(s, ':');
 	if(s == nil)
 		sysfatal("bad diff output3");
 	s++;
 	*pfrom2 = strtol(s, &s, 10);
 	if(*s == ','){
 		s++;
 		*pto2 = strtol(s, &s, 10);
 	}else
 		*pto2 = *pfrom2;
 }

 void
 skiplines(Biobuf *b, char *name, int n)
 {
 	int i;

 	for(i=0; i<n; i++){
 		while(Brdline(b, '\n')==nil){
 			if(Blinelen(b) <= 0)
 				sysfatal("early end of file on %s", name);
 			Bseek(b, Blinelen(b), 1);
 		}
 	}
 }

 void
 copylines(Biobuf *bin, char *nin, Biobuf *bout, char *nout, int n)
 {
 	char buf[4096], *p;
 	int i, m;

 	for(i=0; i<n; i++){
 		while((p=Brdline(bin, '\n'))==nil){
 			if(Blinelen(bin) <= 0)
 				sysfatal("early end of file on %s", nin);
 			m = Blinelen(bin);
 			if(m > sizeof buf)
 				m = sizeof buf;
 			m = Bread(bin, buf, m);
 			if(Bwrite(bout, buf, m) != m)
 				sysfatal("error writing %s: %r", nout);
 		}
 		if(Bwrite(bout, p, Blinelen(bin)) != Blinelen(bin))
 			sysfatal("error writing %s: %r", nout);
 	}
 }

 void
 copy(Biobuf *bin, char *nin, Biobuf *bout, char *nout)
 {
 	char buf[4096];
 	int m;

 	USED(nin);
 	while((m = Bread(bin, buf, sizeof buf)) > 0)
 		if(Bwrite(bout, buf, m) != m)
 			sysfatal("error writing %s: %r", nout);
 }

 void
 idiff(Biobuf *b1, char *name1, Biobuf *b2, char *name2, Biobuf *bdiff, char *namediff, Biobuf *bout, char *nameout)
 {
 	char buf[256], *p;
 	int interactive, defaultanswer, cmd, diffoffset;
 	int n, from1, to1, from2, to2, nf1, nf2;
 	Biobuf berr;

 	nf1 = 1;
 	nf2 = 1;
 	interactive = 1;
 	defaultanswer = 0;
 	Binit(&berr, 2, OWRITE);
 	while(diffoffset = Boffset(bdiff), p = Brdline(bdiff, '\n')){
 		p[Blinelen(bdiff)-1] = '\0';
 		parse(p, &from1, &to1, &cmd, &from2, &to2);
 		p[Blinelen(bdiff)-1] = '\n';
 		n = to1-from1 + to2-from2 + 1;	/* #lines from diff */
 		if(cmd == 'c')
 			n += 2;
 		else if(cmd == 'a')
 			from1++;
 		else if(cmd == 'd')
 			from2++;
 		to1++;	/* make half-open intervals */
 		to2++;
 		if(interactive){
 			p[Blinelen(bdiff)-1] = '\0';
 			fprint(2, "%s\n", p);
 			p[Blinelen(bdiff)-1] = '\n';
 			copylines(bdiff, namediff, &berr, "<stderr>", n);
 			Bflush(&berr);
 		}else
 			skiplines(bdiff, namediff, n);
 		do{
 			if(interactive){
 				fprint(2, "? ");
 				memset(buf, 0, sizeof buf);
 				if(read(0, buf, sizeof buf - 1) < 0)
 					sysfatal("read console: %r");
 			}else
 				buf[0] = defaultanswer;

 			switch(buf[0]){
 			case '>':
 				copylines(b1, name1, bout, nameout, from1-nf1);
 				skiplines(b1, name1, to1-from1);
 				skiplines(b2, name2, from2-nf2);
 				copylines(b2, name2, bout, nameout, to2-from2);
 				break;
 			case '<':
 				copylines(b1, name1, bout, nameout, to1-nf1);
 				skiplines(b2, name2, to2-nf2);
 				break;
 			case '=':
 				copylines(b1, name1, bout, nameout, from1-nf1);
 				skiplines(b1, name1, to1-from1);
 				skiplines(b2, name2, to2-nf2);
 				if(Bseek(bdiff, diffoffset, 0) != diffoffset)
 					sysfatal("seek in diff output: %r");
 				copylines(bdiff, namediff, bout, nameout, n+1);
 				break;
 			case '!':
 				runcmd(buf+1);
 				break;
 			case 'q':
 				if(buf[1]=='<' || buf[1]=='>' || buf[1]=='='){
 					interactive = 0;
 					defaultanswer = buf[1];
 				}else
 					fprint(2, "must be q<, q>, or q=\n");
 				break;
 			default:
 				fprint(2, "expect: <, >, =, q<, q>, q=, !cmd\n");
 				break;
 			}
 		}while(buf[0] != '<' && buf[0] != '>' && buf[0] != '=');
 		nf1 = to1;
 		nf2 = to2;
 	}
 	copy(b1, name1, bout, nameout);
 }
	/*
	* interactive diff, inspired/stolen from
	* kernighan and pike, _unix programming environment_.
	*/

	#include <u.h>
	#include <libc.h>
	#include <bio.h>

	#define opentemp idiffopentemp

	int diffbflag;
	int diffwflag;

	void copy(Biobuf, char, Biobuf, char);
	void idiff(Biobuf, char, Biobuf, char, Biobuf, char, Biobuf, char);
	int opentemp(char*, int, long);
	void rundiff(char, char, int);

	void
	usage(void)
	{
	fprint(2, "usage: idiff [-bw] file1 file2\n");
	exits("usage");
	}

	void
	main(int argc, char **argv)
	{
	int fd, ofd;
	char diffout[40], idiffout[40];
	Biobuf b1, b2, bdiff, bout, bstdout;
	Dir *d;

	ARGBEGIN{
	default:
	usage();
	case 'b':
	diffbflag++;
	break;
	case 'w':
	diffwflag++;
	break;
	}ARGEND

	if(argc != 2)
	usage();

	if((d = dirstat(argv[0])) == nil)
	sysfatal("stat %s: %r", argv[0]);
	if(d->mode&DMDIR)
	sysfatal("%s is a directory", argv[0]);
	free(d);
	if((d = dirstat(argv[1])) == nil)
	sysfatal("stat %s: %r", argv[1]);
	if(d->mode&DMDIR)
	sysfatal("%s is a directory", argv[1]);
	free(d);

	if((b1 = Bopen(argv[0], OREAD)) == nil)
	sysfatal("open %s: %r", argv[0]);
	if((b2 = Bopen(argv[1], OREAD)) == nil)
	sysfatal("open %s: %r", argv[1]);

	strcpy(diffout, "/tmp/idiff.XXXXXX");
	fd = opentemp(diffout, ORDWR\|ORCLOSE, 0);
	strcpy(idiffout, "/tmp/idiff.XXXXXX");
	ofd = opentemp(idiffout, ORDWR\|ORCLOSE, 0);
	rundiff(argv[0], argv[1], fd);
	seek(fd, 0, 0);
	Binit(&bdiff, fd, OREAD);
	Binit(&bout, ofd, OWRITE);
	idiff(b1, argv[0], b2, argv[1], &bdiff, diffout, &bout, idiffout);
	Bterm(&bdiff);
	Bflush(&bout);
	seek(ofd, 0, 0);
	Binit(&bout, ofd, OREAD);
	Binit(&bstdout, 1, OWRITE);
	copy(&bout, idiffout, &bstdout, "<stdout>");
	exits(nil);
	}

	int
	opentemp(char *template, int mode, long perm)
	{
	int fd;
	Dir d;

	fd = mkstemp(template);
	if(fd < 0)
	sysfatal("could not create temporary file");
	nulldir(&d);
	d.mode = perm;
	dirfwstat(fd, &d);

	return fd;
	}

	void
	rundiff(char arg1, char arg2, int outfd)
	{
	char arg[10], p;
	int narg, pid;
	Waitmsg *w;

	narg = 0;
	arg[narg++] = "9";
	arg[narg++] = "diff";
	arg[narg++] = "-n";
	if(diffbflag)
	arg[narg++] = "-b";
	if(diffwflag)
	arg[narg++] = "-w";
	arg[narg++] = arg1;
	arg[narg++] = arg2;
	arg[narg] = nil;

	switch(pid = fork()){
	case -1:
	sysfatal("fork: %r");

	case 0:
	dup(outfd, 1);
	close(0);
	exec("9", arg);
	sysfatal("exec: %r");

	default:
	w = wait();
	if(w==nil)
	sysfatal("wait: %r");
	if(w->pid != pid)
	sysfatal("wait got unexpected pid %d", w->pid);
	if((p = strchr(w->msg, ':')) && strcmp(p, ": some") != 0)
	sysfatal("%s", w->msg);
	free(w);
	}
	}

	void
	runcmd(char *cmd)
	{
	char *arg[10];
	int narg, pid, wpid;

	narg = 0;
	arg[narg++] = "rc";
	arg[narg++] = "-c";
	arg[narg++] = cmd;
	arg[narg] = nil;

	switch(pid = fork()){
	case -1:
	sysfatal("fork: %r");

	case 0:
	exec("rc", arg);
	sysfatal("exec: %r");

	default:
	wpid = waitpid();
	if(wpid < 0)
	sysfatal("wait: %r");
	if(wpid != pid)
	sysfatal("wait got unexpected pid %d", wpid);
	}
	}

	void
	parse(char s, int pfrom1, int pto1, int pcmd, int pfrom2, int pto2)
	{
	pfrom1 = pto1 = pfrom2 = pto2 = 0;

	s = strchr(s, ':');
	if(s == nil)
	sysfatal("bad diff output0");
	s++;
	*pfrom1 = strtol(s, &s, 10);
	if(*s == ','){
	s++;
	*pto1 = strtol(s, &s, 10);
	}else
	pto1 = pfrom1;
	if(*s++ != ' ')
	sysfatal("bad diff output1");
	pcmd = s++;
	if(*s++ != ' ')
	sysfatal("bad diff output2");
	s = strchr(s, ':');
	if(s == nil)
	sysfatal("bad diff output3");
	s++;
	*pfrom2 = strtol(s, &s, 10);
	if(*s == ','){
	s++;
	*pto2 = strtol(s, &s, 10);
	}else
	pto2 = pfrom2;
	}

	void
	skiplines(Biobuf b, char name, int n)
	{
	int i;

	for(i=0; i<n; i++){
	while(Brdline(b, '\n')==nil){
	if(Blinelen(b) <= 0)
	sysfatal("early end of file on %s", name);
	Bseek(b, Blinelen(b), 1);
	}
	}
	}

	void
	copylines(Biobuf bin, char nin, Biobuf bout, char nout, int n)
	{
	char buf[4096], *p;
	int i, m;

	for(i=0; i<n; i++){
	while((p=Brdline(bin, '\n'))==nil){
	if(Blinelen(bin) <= 0)
	sysfatal("early end of file on %s", nin);
	m = Blinelen(bin);
	if(m > sizeof buf)
	m = sizeof buf;
	m = Bread(bin, buf, m);
	if(Bwrite(bout, buf, m) != m)
	sysfatal("error writing %s: %r", nout);
	}
	if(Bwrite(bout, p, Blinelen(bin)) != Blinelen(bin))
	sysfatal("error writing %s: %r", nout);
	}
	}

	void
	copy(Biobuf bin, char nin, Biobuf bout, char nout)
	{
	char buf[4096];
	int m;

	USED(nin);
	while((m = Bread(bin, buf, sizeof buf)) > 0)
	if(Bwrite(bout, buf, m) != m)
	sysfatal("error writing %s: %r", nout);
	}

	void
	idiff(Biobuf b1, char name1, Biobuf b2, char name2, Biobuf bdiff, char namediff, Biobuf bout, char nameout)
	{
	char buf[256], *p;
	int interactive, defaultanswer, cmd, diffoffset;
	int n, from1, to1, from2, to2, nf1, nf2;
	Biobuf berr;

	nf1 = 1;
	nf2 = 1;
	interactive = 1;
	defaultanswer = 0;
	Binit(&berr, 2, OWRITE);
	while(diffoffset = Boffset(bdiff), p = Brdline(bdiff, '\n')){
	p[Blinelen(bdiff)-1] = '\0';
	parse(p, &from1, &to1, &cmd, &from2, &to2);
	p[Blinelen(bdiff)-1] = '\n';
	n = to1-from1 + to2-from2 + 1; /* #lines from diff */
	if(cmd == 'c')
	n += 2;
	else if(cmd == 'a')
	from1++;
	else if(cmd == 'd')
	from2++;
	to1++; /* make half-open intervals */
	to2++;
	if(interactive){
	p[Blinelen(bdiff)-1] = '\0';
	fprint(2, "%s\n", p);
	p[Blinelen(bdiff)-1] = '\n';
	copylines(bdiff, namediff, &berr, "<stderr>", n);
	Bflush(&berr);
	}else
	skiplines(bdiff, namediff, n);
	do{
	if(interactive){
	fprint(2, "? ");
	memset(buf, 0, sizeof buf);
	if(read(0, buf, sizeof buf - 1) < 0)
	sysfatal("read console: %r");
	}else
	buf[0] = defaultanswer;

	switch(buf[0]){
	case '>':
	copylines(b1, name1, bout, nameout, from1-nf1);
	skiplines(b1, name1, to1-from1);
	skiplines(b2, name2, from2-nf2);
	copylines(b2, name2, bout, nameout, to2-from2);
	break;
	case '<':
	copylines(b1, name1, bout, nameout, to1-nf1);
	skiplines(b2, name2, to2-nf2);
	break;
	case '=':
	copylines(b1, name1, bout, nameout, from1-nf1);
	skiplines(b1, name1, to1-from1);
	skiplines(b2, name2, to2-nf2);
	if(Bseek(bdiff, diffoffset, 0) != diffoffset)
	sysfatal("seek in diff output: %r");
	copylines(bdiff, namediff, bout, nameout, n+1);
	break;
	case '!':
	runcmd(buf+1);
	break;
	case 'q':
	if(buf[1]=='<' \|\| buf[1]=='>' \|\| buf[1]=='='){
	interactive = 0;
	defaultanswer = buf[1];
	}else
	fprint(2, "must be q<, q>, or q=\n");
	break;
	default:
	fprint(2, "expect: <, >, =, q<, q>, q=, !cmd\n");
	break;
	}
	}while(buf[0] != '<' && buf[0] != '>' && buf[0] != '=');
	nf1 = to1;
	nf2 = to2;
	}
	copy(b1, name1, bout, nameout);
	}