cosmopolitan/third_party/less/main.c

asm(".ident\t\"\\n\\n\
Less\\n\
Copyright (C) 1984-2023  Mark Nudelman\\n\
\\n\
Redistribution and use in source and binary forms, with or without\\n\
modification, are permitted provided that the following conditions\\n\
are met:\\n\
1. Redistributions of source code must retain the above copyright\\n\
   notice, this list of conditions and the following disclaimer.\\n\
2. Redistributions in binary form must reproduce the above copyright\\n\
   notice in the documentation and/or other materials provided with\\n\
   the distribution.\\n\
\\n\
THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY\\n\
EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE\\n\
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR\\n\
PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE\\n\
FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR\\n\
CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT\\n\
OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR\\n\
BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,\\n\
WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE\\n\
OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN\\n\
IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.\"");

/*
 * Copyright (C) 1984-2023  Mark Nudelman
 *
 * You may distribute under the terms of either the GNU General Public
 * License or the Less License, as specified in the README file.
 *
 * For more information, see the README file.
 */


/*
 * Entry point, initialization, miscellaneous routines.
 */

#include "less.h"
#if MSDOS_COMPILER==WIN32C
#define WIN32_LEAN_AND_MEAN
/* #include <windows.h> */
#endif

public char *   every_first_cmd = NULL;
public int      new_file;
public int      is_tty;
public IFILE    curr_ifile = NULL_IFILE;
public IFILE    old_ifile = NULL_IFILE;
public struct scrpos initial_scrpos;
public POSITION start_attnpos = NULL_POSITION;
public POSITION end_attnpos = NULL_POSITION;
public int      wscroll;
public char *   progname;
public int      quitting;
public int      secure;
public int      dohelp;

#if LOGFILE
public int      logfile = -1;
public int      force_logfile = FALSE;
public char *   namelogfile = NULL;
#endif

#if EDITOR
public char *   editor;
public char *   editproto;
#endif

#if TAGS
extern char *   tags;
extern char *   tagoption;
extern int      jump_sline;
#endif

#ifdef WIN32
static char consoleTitle[256];
#endif

public int      one_screen;
extern int      less_is_more;
extern int      missing_cap;
extern int      know_dumb;
extern int      pr_type;
extern int      quit_if_one_screen;
extern int      no_init;
extern int      errmsgs;
extern int      redraw_on_quit;
extern int      term_init_done;
extern int      first_time;

/*
 * Entry point.
 */
int main(int argc, char *argv[])
{
	IFILE ifile;
	char *s;

#ifdef __EMX__
	_response(&argc, &argv);
	_wildcard(&argc, &argv);
#endif

	progname = *argv++;
	argc--;

#if SECURE
	secure = 1;
#else
	secure = 0;
	s = lgetenv("LESSSECURE");
	if (!isnullenv(s))
		secure = 1;
#endif

#ifdef WIN32
	if (getenv("HOME") == NULL)
	{
		/*
		 * If there is no HOME environment variable,
		 * try the concatenation of HOMEDRIVE + HOMEPATH.
		 */
		char *drive = getenv("HOMEDRIVE");
		char *path  = getenv("HOMEPATH");
		if (drive != NULL && path != NULL)
		{
			char *env = (char *) ecalloc(strlen(drive) + 
					strlen(path) + 6, sizeof(char));
			strcpy(env, "HOME=");
			strcat(env, drive);
			strcat(env, path);
			putenv(env);
		}
	}
	GetConsoleTitle(consoleTitle, sizeof(consoleTitle)/sizeof(char));
#endif /* WIN32 */

	/*
	 * Process command line arguments and LESS environment arguments.
	 * Command line arguments override environment arguments.
	 */
	is_tty = isatty(1);
	init_mark();
	init_cmds();
	init_poll();
	get_term();
	init_charset();
	init_line();
	init_cmdhist();
	init_option();
	init_search();

	/*
	 * If the name of the executable program is "more",
	 * act like LESS_IS_MORE is set.
	 */
	s = last_component(progname);
	if (strcmp(s, "more") == 0)
		less_is_more = 1;

	init_prompt();

	s = lgetenv(less_is_more ? "MORE" : "LESS");
	if (s != NULL)
		scan_option(s);

#define isoptstring(s)  (((s)[0] == '-' || (s)[0] == '+') && (s)[1] != '\0')
	while (argc > 0 && (isoptstring(*argv) || isoptpending()))
	{
		s = *argv++;
		argc--;
		if (strcmp(s, "--") == 0)
			break;
		scan_option(s);
	}
#undef isoptstring

	if (isoptpending())
	{
		/*
		 * Last command line option was a flag requiring a
		 * following string, but there was no following string.
		 */
		nopendopt();
		quit(QUIT_OK);
	}

	expand_cmd_tables();

#if EDITOR
	editor = lgetenv("VISUAL");
	if (editor == NULL || *editor == '\0')
	{
		editor = lgetenv("EDITOR");
		if (isnullenv(editor))
			editor = EDIT_PGM;
	}
	editproto = lgetenv("LESSEDIT");
	if (isnullenv(editproto))
		editproto = "%E ?lm+%lm. %g";
#endif

	/*
	 * Call get_ifile with all the command line filenames
	 * to "register" them with the ifile system.
	 */
	ifile = NULL_IFILE;
	if (dohelp)
		ifile = get_ifile(FAKE_HELPFILE, ifile);
	while (argc-- > 0)
	{
#if (MSDOS_COMPILER && MSDOS_COMPILER != DJGPPC)
		/*
		 * Because the "shell" doesn't expand filename patterns,
		 * treat each argument as a filename pattern rather than
		 * a single filename.  
		 * Expand the pattern and iterate over the expanded list.
		 */
		struct textlist tlist;
		char *filename;
		char *gfilename;
		char *qfilename;
		
		gfilename = lglob(*argv++);
		init_textlist(&tlist, gfilename);
		filename = NULL;
		while ((filename = forw_textlist(&tlist, filename)) != NULL)
		{
			qfilename = shell_unquote(filename);
			(void) get_ifile(qfilename, ifile);
			free(qfilename);
			ifile = prev_ifile(NULL_IFILE);
		}
		free(gfilename);
#else
		(void) get_ifile(*argv++, ifile);
		ifile = prev_ifile(NULL_IFILE);
#endif
	}
	/*
	 * Set up terminal, etc.
	 */
	if (!is_tty)
	{
		/*
		 * Output is not a tty.
		 * Just copy the input file(s) to output.
		 */
		set_output(1); /* write to stdout */
		SET_BINARY(1);
		if (edit_first() == 0)
		{
			do {
				cat_file();
			} while (edit_next(1) == 0);
		}
		quit(QUIT_OK);
	}

	if (missing_cap && !know_dumb)
		error("WARNING: terminal is not fully functional", NULL_PARG);
	open_getchr();
	raw_mode(1);
	init_signals(1);

	/*
	 * Select the first file to examine.
	 */
#if TAGS
	if (tagoption != NULL || strcmp(tags, "-") == 0)
	{
		/*
		 * A -t option was given.
		 * Verify that no filenames were also given.
		 * Edit the file selected by the "tags" search,
		 * and search for the proper line in the file.
		 */
		if (nifile() > 0)
		{
			error("No filenames allowed with -t option", NULL_PARG);
			quit(QUIT_ERROR);
		}
		findtag(tagoption);
		if (edit_tagfile())  /* Edit file which contains the tag */
			quit(QUIT_ERROR);
		/*
		 * Search for the line which contains the tag.
		 * Set up initial_scrpos so we display that line.
		 */
		initial_scrpos.pos = tagsearch();
		if (initial_scrpos.pos == NULL_POSITION)
			quit(QUIT_ERROR);
		initial_scrpos.ln = jump_sline;
	} else
#endif
	{
		if (edit_first())
			quit(QUIT_ERROR);
		/*
		 * See if file fits on one screen to decide whether 
		 * to send terminal init. But don't need this 
		 * if -X (no_init) overrides this (see init()).
		 */
		if (quit_if_one_screen)
		{
			if (nifile() > 1) /* If more than one file, -F cannot be used */
				quit_if_one_screen = FALSE;
			else if (!no_init)
				one_screen = get_one_screen();
		}
	}

	if (errmsgs > 0)
	{
		/*
		 * We displayed some messages on error output
		 * (file descriptor 2; see flush()).
		 * Before erasing the screen contents, wait for a keystroke.
		 */
		less_printf("Press RETURN to continue ", NULL_PARG);
		get_return();
		putchr('\n');
	}
	set_output(1);
	init();
	commands();
	quit(QUIT_OK);
	/*NOTREACHED*/
	return (0);
}

/*
 * Copy a string to a "safe" place
 * (that is, to a buffer allocated by calloc).
 */
public char * save(constant char *s)
{
	char *p;

	p = (char *) ecalloc(strlen(s)+1, sizeof(char));
	strcpy(p, s);
	return (p);
}

public void out_of_memory(void)
{
	error("Cannot allocate memory", NULL_PARG);
	quit(QUIT_ERROR);
}

/*
 * Allocate memory.
 * Like calloc(), but never returns an error (NULL).
 */
public void * ecalloc(int count, unsigned int size)
{
	void * p;

	p = (void *) calloc(count, size);
	if (p == NULL)
		out_of_memory();
	return p;
}

/*
 * Skip leading spaces in a string.
 */
public char * skipsp(char *s)
{
	while (*s == ' ' || *s == '\t')
		s++;
	return (s);
}

/*
 * See how many characters of two strings are identical.
 * If uppercase is true, the first string must begin with an uppercase
 * character; the remainder of the first string may be either case.
 */
public int sprefix(char *ps, char *s, int uppercase)
{
	int c;
	int sc;
	int len = 0;

	for ( ;  *s != '\0';  s++, ps++)
	{
		c = *ps;
		if (uppercase)
		{
			if (len == 0 && ASCII_IS_LOWER(c))
				return (-1);
			if (ASCII_IS_UPPER(c))
				c = ASCII_TO_LOWER(c);
		}
		sc = *s;
		if (len > 0 && ASCII_IS_UPPER(sc))
			sc = ASCII_TO_LOWER(sc);
		if (c != sc)
			break;
		len++;
	}
	return (len);
}

/*
 * Exit the program.
 */
public void quit(int status)
{
	static int save_status;

	/*
	 * Put cursor at bottom left corner, clear the line,
	 * reset the terminal modes, and exit.
	 */
	if (status < 0)
		status = save_status;
	else
		save_status = status;
	quitting = 1;
	check_altpipe_error();
	if (interactive())
		clear_bot();
	deinit();
	flush();
	if (redraw_on_quit && term_init_done)
	{
		/*
		 * The last file text displayed might have been on an 
		 * alternate screen, which now (since deinit) cannot be seen.
		 * redraw_on_quit tells us to redraw it on the main screen.
		 */
		first_time = 1; /* Don't print "skipping" or tildes */
		repaint();
		flush();
	}
	edit((char*)NULL);
	save_cmdhist();
	raw_mode(0);
#if MSDOS_COMPILER && MSDOS_COMPILER != DJGPPC
	/* 
	 * If we don't close 2, we get some garbage from
	 * 2's buffer when it flushes automatically.
	 * I cannot track this one down  RB
	 * The same bug shows up if we use ^C^C to abort.
	 */
	close(2);
#endif
#ifdef WIN32
	SetConsoleTitle(consoleTitle);
#endif
	close_getchr();
	exit(status);
}