/*	$NetBSD: qsubst.c,v 1.8 2004/11/01 21:36:11 dsl Exp $	*/

/*
 * qsubst -- designed for renaming routines existing in a whole bunch
 *  of files.  Needs -ltermcap.
 *
 * Usage:
 *
 * qsubst str1 str2 [ options ]
 *
 * qsubst reads its options (see below) to get a list of files.  For
 *  each file on this list, it then replaces str1 with str2 wherever
 *  possible in that file, depending on user input (see below).  The
 *  result is written back onto the original file.
 *
 * For each possible substitution, the user is prompted with a few
 *  lines before and after the line containing the string to be
 *  substituted.  The string itself is displayed using the terminal's
 *  standout mode, if any.  Then one character is read from the
 *  terminal.  This is then interpreted as follows (this is designed to
 *  be like Emacs' query-replace-string):
 *
 *	space	replace this occurrence and go on to the next one
 *	.	replace this occurrence and don't change any more in
 *		this file (ie, go on to the next file).
 *	,	tentatively replace this occurrence.  The lines as they
 *		would look if the substitution were made are printed
 *		out.  Then another character is read and it is used to
 *		decide the result (possibly undoing the tentative
 *		replacement).
 *	n	don't change this one, but go on to the next one
 *	^G	don't change this one or any others in this file, but
 *		instead go on to the next file.
 *	!	change the rest in this file without asking, then go on
 *		to the next file (at which point qsubst will start
 *		asking again).
 *	?	print out the current filename and ask again.
 *
 * The first two arguments to qsubst are always the string to replace
 *  and the string to replace it with.  The options are as follows:
 *
 *	-w	The search string is considered as a C symbol; it must
 *		be bounded by non-symbol characters.  This option
 *		toggles.  (`w' for `word'.)
 *	-!	Enter ! mode automatically at the beginning of each
 *		file.
 *	-go	Same as -!
 *	-noask	Same as -!
 *	-nogo	Negate -go
 *	-ask	Negate -noask (same as -nogo)
 *	-cN	(N is a number) Give N lines of context above and below
 *		the line with the match when prompting the user.
 *	-CAN	(N is a number) Give N lines of context above the line
 *		with the match when prompting the user.
 *	-CBN	(N is a number) Give N lines of context below the line
 *		with the match when prompting the user.
 *	-f filename
 *		The filename following the -f argument is one of the
 *		files qsubst should perform substitutions in.
 *	-F filename
 *		qsubst should read the named file to get the names of
 *		files to perform substitutions in.  The names should
 *		appear one to a line.
 *
 * The default amount of context is -c2, that is, two lines above and
 *  two lines below the line with the match.
 *
 * Arguments not beginning with a - sign in the options field are
 *  implicitly preceded by -f.  Thus, -f is really needed only when the
 *  file name begins with a - sign.
 *
 * qsubst reads its options in order and processes files as it gets
 *  them.  This means, for example, that a -go will affect only files
 *  from -f or -F options appearing after the -go option.
 *
 * The most context you can get is ten lines each, above and below
 *  (corresponding to -c10).
 *
 * Str1 is limited to 512 characters; there is no limit on the size of
 *  str2.  Neither one may contain a NUL.
 *
 * NULs in the file may cause qsubst to make various mistakes.
 *
 * If any other program modifies the file while qsubst is running, all
 *  bets are off.
 *
 * This program is in the public domain.  Anyone may use it in any way
 *  for any purpose.  Of course, it's also up to you to determine
 *  whether what it does is suitable for you; the above comments may
 *  help, but I can't promise they're accurate.  It's free, and you get
 *  what you pay for.
 *
 * If you find any bugs I would appreciate hearing about them,
 *  especially if you also fix them.
 *
 *					der Mouse
 *
 *			       mouse@rodents.montreal.qc.ca
 */
#include <sys/cdefs.h>

#ifndef lint
__RCSID("$NetBSD: qsubst.c,v 1.8 2004/11/01 21:36:11 dsl Exp $");
#endif

#include <sys/file.h>

#include <ctype.h>
#include <errno.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <strings.h>
#include <termcap.h>
#include <termios.h>
#include <unistd.h>

extern const char *__progname;

#define MAX_C_A 10
#define MAX_C_B 10
#define BUF_SIZ 1024

static int debugging;
static FILE *tempf;
static long tbeg;
static FILE *workf;
static char *str1;
static char *str2;
static int s1l;
static int s2l;
static long nls[MAX_C_A + 1];
static char buf[(BUF_SIZ * 2) + 2];
static char *bufp;
static char *bufp0;
static char *bufpmax;
static int rahead;
static int cabove;
static int cbelow;
static int wordmode;
static int flying;
static int flystate;
static int allfly;
static const char *nullstr = "";
static int ul_;
static char *current_file;
static const char *beginul;
static const char *endul;
static char tcp_buf[1024];
static char cap_buf[1024];
static struct termios orig_tio;

static void 
tstp_self(void)
{
	void (*old_tstp) (int);
	int mask;

	mask = sigblock(0);
	kill(getpid(), SIGTSTP);
	old_tstp = signal(SIGTSTP, SIG_DFL);
	sigsetmask(mask & ~sigmask(SIGTSTP));
	signal(SIGTSTP, old_tstp);
}

/* ARGSUSED */
static void 
sigtstp(int sig)
{
	struct termios tio;

	if (tcgetattr(0, &tio) < 0) {
		tstp_self();
		return;
	}
	tcsetattr(0, TCSAFLUSH | TCSASOFT, &orig_tio);
	tstp_self();
	tcsetattr(0, TCSADRAIN | TCSASOFT, &tio);
}

static void 
limit_above_below(void)
{
	if (cabove > MAX_C_A) {
		cabove = MAX_C_A;
	}
	if (cbelow > MAX_C_B) {
		cbelow = MAX_C_B;
	}
}

static int 
issymchar(unsigned char c)
{
	return (isascii(c) && (isalnum(c) || (c == '_') || (c == '$')));
}

static int 
foundit(void)
{
	if (wordmode) {
		return (!issymchar(bufp[-1]) &&
		    !issymchar(bufp[-2 - s1l]) &&
		    !bcmp(bufp - 1 - s1l, str1, s1l));
	} else {
		return (!bcmp(bufp - s1l, str1, s1l));
	}
}

static int 
putcharf(int c)
{
	return (putchar(c));
}

static void 
put_ul(char *s)
{
	if (ul_) {
		for (; *s; s++) {
			printf("_\b%c", *s);
		}
	} else {
		tputs(beginul, 1, putcharf);
		fputs(s, stdout);
		tputs(endul, 1, putcharf);
	}
}

static int 
getc_cbreak(void)
{
	struct termios tio;
	struct termios otio;
	char c;

	if (tcgetattr(0, &tio) < 0)
		return (getchar());
	otio = tio;
	tio.c_lflag &= ~(ICANON | ECHOKE | ECHOE | ECHO | ECHONL);
	tio.c_cc[VMIN] = 1;
	tio.c_cc[VTIME] = 0;
	tcsetattr(0, TCSANOW | TCSASOFT, &tio);
	switch (read(0, &c, 1)) {
	case -1:
		break;
	case 0:
		break;
	case 1:
		break;
	}
	tcsetattr(0, TCSANOW | TCSASOFT, &otio);
	return (c);
}

static int 
doit(void)
{
	long save;
	int i;
	int lastnl;
	int use_replacement;

	if (flying) {
		return (flystate);
	}
	use_replacement = 0;
	save = ftell(workf);
	do {
		for (i = MAX_C_A - cabove; nls[i] < 0; i++);
		fseek(workf, nls[i], 0);
		for (i = save - nls[i] - rahead; i; i--) {
			putchar(getc(workf));
		}
		put_ul(use_replacement ? str2 : str1);
		fseek(workf, save + s1l - rahead, 0);
		lastnl = 0;
		i = cbelow + 1;
		while (i > 0) {
			int c;
			c = getc(workf);
			if (c == EOF) {
				clearerr(workf);
				break;
			}
			putchar(c);
			lastnl = 0;
			if (c == '\n') {
				i--;
				lastnl = 1;
			}
		}
		if (!lastnl)
			printf("\n[no final newline] ");
		fseek(workf, save, 0);
		i = -1;
		while (i == -1) {
			switch (getc_cbreak()) {
			case ' ':
				i = 1;
				break;
			case '.':
				i = 1;
				flying = 1;
				flystate = 0;
				break;
			case 'n':
				i = 0;
				break;
			case '\7':
				i = 0;
				flying = 1;
				flystate = 0;
				break;
			case '!':
				i = 1;
				flying = 1;
				flystate = 1;
				break;
			case ',':
				use_replacement = !use_replacement;
				i = -2;
				printf("(using %s string gives)\n",
				    use_replacement ? "new" : "old");
				break;
			case '?':
				printf("File is `%s'\n", current_file);
				break;
			default:
				putchar('\7');
				break;
			}
		}
	} while (i < 0);
	if (i) {
		printf("(replacing");
	} else {
		printf("(leaving");
	}
	if (flying) {
		if (flystate == i) {
			printf(" this and all the rest");
		} else if (flystate) {
			printf(" this, replacing all the rest");
		} else {
			printf(" this, leaving all the rest");
		}
	}
	printf(")\n");
	return (i);
}

static void 
add_shift(long *a, long e, int n)
{
	int i;

	n--;
	for (i = 0; i < n; i++) {
		a[i] = a[i + 1];
	}
	a[n] = e;
}

static void 
process_file(char *fn)
{
	int i;
	long n;
	int c;

	workf = fopen(fn, "r+");
	if (workf == NULL) {
		fprintf(stderr, "%s: cannot read %s\n", __progname, fn);
		return;
	}
	printf("(file: %s)\n", fn);
	current_file = fn;
	for (i = 0; i <= MAX_C_A; i++) {
		nls[i] = -1;
	}
	nls[MAX_C_A] = 0;
	tbeg = -1;
	if (wordmode) {
		bufp0 = &buf[1];
		rahead = s1l + 1;
		buf[0] = '\0';
	} else {
		bufp0 = &buf[0];
		rahead = s1l;
	}
	if (debugging) {
		printf("[rahead = %d, bufp0-buf = %ld]\n",
		    rahead, (long) (bufp0 - &buf[0]));
	}
	n = 0;
	bufp = bufp0;
	bufpmax = &buf[sizeof(buf) - s1l - 2];
	flying = allfly;
	flystate = 1;
	while (1) {
		c = getc(workf);
		if (c == EOF) {
			if (tbeg >= 0) {
				if (bufp > bufp0)
					fwrite(bufp0, 1, bufp - bufp0, tempf);
				fseek(workf, tbeg, 0);
				n = ftell(tempf);
				fseek(tempf, 0L, 0);
				for (; n; n--) {
					putc(getc(tempf), workf);
				}
				fflush(workf);
				ftruncate(fileno(workf), ftell(workf));
			}
			fclose(workf);
			return;
		}
		*bufp++ = c;
		n++;
		if (debugging) {
			printf("[got %c, n now %ld, bufp-buf %ld]\n",
			    c, n, (long) (bufp - bufp0));
		}
		if ((n >= rahead) && foundit() && doit()) {
			int wbehind;
			if (debugging) {
				printf("[doing change]\n");
			}
			wbehind = 1;
			if (tbeg < 0) {
				tbeg = ftell(workf) - rahead;
				fseek(tempf, 0L, 0);
				if (debugging) {
					printf("[tbeg set to %d]\n",
					    (int)tbeg);
				}
				wbehind = 0;
			}
			if (bufp[-1] == '\n')
				add_shift(nls, ftell(workf), MAX_C_A + 1);
			if ((n > rahead) && wbehind) {
				fwrite(bufp0, 1, n - rahead, tempf);
				if (debugging) {
					printf("[writing %ld from bufp0]\n",
					    n - rahead);
				}
			}
			fwrite(str2, 1, s2l, tempf);
			n = rahead - s1l;
			if (debugging) {
				printf("[n now %ld]\n", n);
			}
			if (n > 0) {
				bcopy(bufp - n, bufp0, n);
				if (debugging) {
					printf("[copying %ld back]\n", n);
				}
			}
			bufp = bufp0 + n;
		} else {
			if (bufp[-1] == '\n')
				add_shift(nls, ftell(workf), MAX_C_A + 1);
			if (bufp >= bufpmax) {
				if (tbeg >= 0) {
					fwrite(bufp0, 1, n - rahead, tempf);
					if (debugging) {
						printf("[flushing %ld]\n",
						    n - rahead);
					}
				}
				n = rahead;
				bcopy(bufp - n, bufp0, n);
				if (debugging) {
					printf("[n now %ld]\n[copying %ld back]\n", n, n);
				}
				bufp = bufp0 + n;
			}
		}
	}
}

static void 
process_indir_file(char *fn)
{
	char newfn[1024];
	FILE *f;

	f = fopen(fn, "r");
	if (f == NULL) {
		fprintf(stderr, "%s: cannot read %s\n", __progname, fn);
		return;
	}
	while (fgets(newfn, sizeof(newfn), f) == newfn) {
		newfn[strlen(newfn) - 1] = '\0';
		process_file(newfn);
	}
	fclose(f);
}

int 
main(int ac, char **av)
{
	int skip;
	char *cp;

	if (ac < 3) {
		fprintf(stderr, "usage: %s str1 str2 [ -w -! -noask -go -f file -F file ]\n",
		    __progname);
		exit(1);
	}
	cp = getenv("TERM");
	if (cp == 0) {
		beginul = nullstr;
		endul = nullstr;
	} else {
		if (tgetent(tcp_buf, cp) != 1) {
			beginul = nullstr;
			endul = nullstr;
		} else {
			cp = cap_buf;
			if (tgetflag("os") || tgetflag("ul")) {
				ul_ = 1;
			} else {
				ul_ = 0;
				beginul = tgetstr("us", &cp);
				if (beginul == 0) {
					beginul = tgetstr("so", &cp);
					if (beginul == 0) {
						beginul = nullstr;
						endul = nullstr;
					} else {
						endul = tgetstr("se", &cp);
					}
				} else {
					endul = tgetstr("ue", &cp);
				}
			}
		}
	}
	{
		static char tmp[] = "/tmp/qsubst.XXXXXX";
		int fd;
		fd = mkstemp(&tmp[0]);
		if (fd < 0) {
			fprintf(stderr, "%s: cannot create temp file: %s\n",
			    __progname, strerror(errno));
			exit(1);
		}
		tempf = fdopen(fd, "w+");
	}
	if ((access(av[1], R_OK | W_OK) == 0) &&
	    (access(av[ac - 1], R_OK | W_OK) < 0) &&
	    (access(av[ac - 2], R_OK | W_OK) < 0)) {
		fprintf(stderr, "%s: argument order has changed, it's now: str1 str2 files...\n", __progname);
	}
	str1 = av[1];
	str2 = av[2];
	av += 2;
	ac -= 2;
	s1l = strlen(str1);
	s2l = strlen(str2);
	if (s1l > BUF_SIZ) {
		fprintf(stderr, "%s: search string too long (max %d chars)\n",
		    __progname, BUF_SIZ);
		exit(1);
	}
	tcgetattr(0, &orig_tio);
	signal(SIGTSTP, sigtstp);
	allfly = 0;
	cabove = 2;
	cbelow = 2;
	skip = 0;
	for (ac--, av++; ac; ac--, av++) {
		if (skip > 0) {
			skip--;
			continue;
		}
		if (**av == '-') {
			++*av;
			if (!strcmp(*av, "debug")) {
				debugging++;
			} else if (!strcmp(*av, "w")) {
				wordmode = !wordmode;
			} else if ((strcmp(*av, "!") == 0) ||
				    (strcmp(*av, "go") == 0) ||
			    (strcmp(*av, "noask") == 0)) {
				allfly = 1;
			} else if ((strcmp(*av, "nogo") == 0) ||
			    (strcmp(*av, "ask") == 0)) {
				allfly = 0;
			} else if (**av == 'c') {
				cabove = atoi(++*av);
				cbelow = cabove;
				limit_above_below();
			} else if (**av == 'C') {
				++*av;
				if (**av == 'A') {
					cabove = atoi(++*av);
					limit_above_below();
				} else if (**av == 'B') {
					cbelow = atoi(++*av);
					limit_above_below();
				} else {
					fprintf(stderr, "%s: -C must be -CA or -CB\n", __progname);
				}
			} else if ((strcmp(*av, "f") == 0) ||
			    (strcmp(*av, "F") == 0)) {
				if (++skip >= ac) {
					fprintf(stderr, "%s: -%s what?\n",
					    __progname, *av);
				} else {
					if (**av == 'f') {
						process_file(av[skip]);
					} else {
						process_indir_file(av[skip]);
					}
				}
			}
		} else {
			process_file(*av);
		}
	}
	exit(0);
}