/* inputting files to be patched */

/* $Id: inp.c,v 1.9 1997/04/17 16:15:48 eggert Exp $ */

/*
Copyright 1986, 1988 Larry Wall
Copyright 1991, 1992, 1993, 1997 Free Software Foundation, Inc.

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; see the file COPYING.
If not, write to the Free Software Foundation,
59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/

#define XTERN extern
#include <common.h>
#include <backupfile.h>
#include <pch.h>
#include <util.h>
#undef XTERN
#define XTERN
#include <inp.h>

#define SCCSPREFIX "s."
#define GET "get '%s'"
#define GET_LOCKED "get -e '%s'"
#define SCCSDIFF "get -p '%s' | diff - '%s%s' >/dev/null"

#define RCSSUFFIX ",v"
#define CHECKOUT "co '%s%s'"
#define CHECKOUT_LOCKED "co -l '%s%s'"
#define RCSDIFF "rcsdiff '%s%s' > /dev/null"

/* Input-file-with-indexable-lines abstract type */

static char const **i_ptr;		/* pointers to lines in plan A buffer */

static size_t tibufsize;		/* size of plan b buffers */
#ifndef TIBUFSIZE_MINIMUM
#define TIBUFSIZE_MINIMUM (8 * 1024)	/* minimum value for tibufsize */
#endif
static int tifd = -1;			/* plan b virtual string array */
static char *tibuf[2];			/* plan b buffers */
static LINENUM tiline[2] = {-1, -1};	/* 1st line in each buffer */
static LINENUM lines_per_buf;		/* how many lines per buffer */
static size_t tireclen;			/* length of records in tmp file */
static size_t last_line_size;		/* size of last input line */

static bool plan_a PARAMS ((char const *));/* yield FALSE if memory runs out */
static void plan_b PARAMS ((char const *));
static void report_revision PARAMS ((int));

/* New patch--prepare to edit another file. */

void
re_input()
{
    if (using_plan_a) {
	if (i_ptr) {
	    free (i_ptr);
	    i_ptr = 0;
	}
    }
    else {
	close (tifd);
	tifd = -1;
	free(tibuf[0]);
	tibuf[0] = 0;
	tiline[0] = tiline[1] = -1;
	tireclen = 0;
    }
}

/* Constuct the line index, somehow or other. */

void
scan_input(filename)
char *filename;
{
    using_plan_a = plan_a (filename);
    if (!using_plan_a)
	plan_b(filename);
    switch (verbosity)
      {
      case SILENT:
	break;

      case VERBOSE:
	say ("Patching file %s using Plan %s...\n",
	     filename, using_plan_a ? "A" : "B");
	break;

      case DEFAULT_VERBOSITY:
	say ("patching file %s\n", filename);
	break;
      }
}

/* Report whether a desired revision was found.  */

static void
report_revision (found_revision)
     int found_revision;
{
  if (found_revision)
    {
      if (verbosity == VERBOSE)
	say ("Good.  This file appears to be the %s version.\n", revision);
    }
  else if (force)
    {
      if (verbosity != SILENT)
	say ("Warning: this file doesn't appear to be the %s version--patching anyway.\n",
	     revision);
    }
  else if (batch)
    {
      fatal ("this file doesn't appear to be the %s version--aborting.",
	     revision);
    }
  else
    {
      ask ("This file doesn't appear to be the %s version--patch anyway? [n] ",
	   revision);
      if (*buf != 'y')
	fatal ("aborted");
    }
}


void
get_input_file (filename, outname)
     char const *filename;
     char const *outname;
{
    int elsewhere = strcmp (filename, outname);
    char const *dotslash;

    if (inerrno == -1)
      inerrno = stat (inname, &instat) == 0 ? 0 : errno;
    if (inerrno && ok_to_create_file) {
      int fd;
      if (verbosity == VERBOSE)
	say ("(Creating file %s...)\n", inname);
      if (dry_run) {
	inerrno = 0;
	instat.st_mode = 0;
	instat.st_size = 0;
	return;
      }
      makedirs (inname);
      fd = creat (inname, S_IRUSR|S_IWUSR|S_IRGRP|S_IWGRP|S_IROTH|S_IWOTH);
      if (fd < 0)
	inerrno = errno;
      else {
	inerrno = fstat (fd, &instat) == 0 ? 0 : errno;
	if (close (fd) != 0)
	  inerrno = errno;
      }
    }

    /* For nonexistent or read-only files, look for RCS or SCCS versions.  */
    if (backup_type == numbered_existing
	&& (inerrno
	    || (! elsewhere
		&& (/* No one can write to it.  */
		    (instat.st_mode & (S_IWUSR|S_IWGRP|S_IWOTH)) == 0
		    /* I can't write to it.  */
		    || ((instat.st_mode & (S_IWGRP|S_IWOTH)) == 0
			&& instat.st_uid != getuid ()))))) {
	register char *s;
	struct stat cstat;
	char const *cs = 0;
	char const *filebase;
	size_t dir_len;
	char *lbuf = xmalloc (strlen (filename) + 100);

	strcpy (lbuf, filename);
	dir_len = base_name (lbuf) - lbuf;
	filebase = filename + dir_len;

	/* Put any leading path into `s'.
	   Leave room in lbuf for the diff command.  */
	s = lbuf + 20;
	memcpy (s, filename, dir_len);
	dotslash = *filename=='-' ? "./" : "";

#define try1(f,a1)    (sprintf (s + dir_len, f, a1),    stat (s, &cstat) == 0)
#define try2(f,a1,a2) (sprintf (s + dir_len, f, a1,a2), stat (s, &cstat) == 0)
	if ((   try2 ("RCS/%s%s", filebase, RCSSUFFIX)
	     || try1 ("RCS/%s"  , filebase)
	     || try2 (    "%s%s", filebase, RCSSUFFIX))
	    &&
	    /* Check that RCS file is not working file.
	       Some hosts don't report file name length errors.  */
	    (inerrno
	     || (  (instat.st_dev ^ cstat.st_dev)
		 | (instat.st_ino ^ cstat.st_ino)))) {
	    sprintf (buf, elsewhere ? CHECKOUT : CHECKOUT_LOCKED,
		     dotslash, filename);
	    sprintf (lbuf, RCSDIFF, dotslash, filename);
	    cs = "RCS";
	} else if (   try2 ("SCCS/%s%s", SCCSPREFIX, filebase)
		   || try2 (     "%s%s", SCCSPREFIX, filebase)) {
	    sprintf (buf, elsewhere ? GET : GET_LOCKED, s);
	    sprintf (lbuf, SCCSDIFF, s, dotslash, filename);
	    cs = "SCCS";
	} else if (inerrno)
	    fatal ("can't find %s", filename);
	/* else we can't write to it but it's not under a version
	   control system, so just proceed.  */
	if (cs) {
	    if (!inerrno) {
		if ((instat.st_mode & (S_IWUSR|S_IWGRP|S_IWOTH)) != 0)
		    /* The owner can write to it.  */
		    fatal ("file %s seems to be locked by somebody else under %s",
			   filename, cs);
		/* It might be checked out unlocked.  See if it's safe to
		   check out the default version locked.  */
		if (verbosity == VERBOSE)
		    say ("Comparing file %s to default %s version...\n",
			 filename, cs);
		if (system (lbuf) != 0)
		  {
		    say ("warning: patching file %s, which does not match default %s version\n",
			 filename, cs);
		    cs = 0;
		  }
	    }
	    if (cs)
	      {
		if (dry_run)
		  {
		    if (inerrno)
		      fatal ("Cannot dry run on nonexistent version-controlled file `%s'; invoke `%s' and try again.",
			     filename, buf);
		  }
		else
		  {
		    if (verbosity == VERBOSE)
		      say ("Checking out file %s from %s...\n", filename, cs);
		    if (system (buf) != 0  ||  stat (filename, &instat) != 0)
		      fatal ("can't check out file %s from %s", filename, cs);
		    inerrno = 0;
		  }
	      }
	}
	free (lbuf);
    }
    if (!S_ISREG (instat.st_mode))
	fatal ("%s is not a regular file--can't patch", filename);
}


/* Try keeping everything in memory. */

static bool
plan_a(filename)
     char const *filename;
{
  register char const *s;
  register char const *lim;
  register char const **ptr;
  register char *buffer;
  register LINENUM iline;
  size_t size = instat.st_size;
  size_t allocated_bytes_per_input_byte = sizeof *i_ptr + sizeof (char);
  size_t allocated_bytes = (size + 2) * allocated_bytes_per_input_byte;

  /* Fail if arithmetic overflow occurs during size calculations,
     or if storage isn't available.  */
  if (size != instat.st_size
      || size + 2 < 2
      || allocated_bytes / allocated_bytes_per_input_byte != size + 2
      || ! (ptr = (char const **) malloc (allocated_bytes)))
    return FALSE;

  buffer = (char *) (ptr + (size + 2));

  /* Read the input file, but don't bother reading it if it's empty.
     During dry runs, empty files may not actually exist.  */
  if (size)
    {
      int ifd = open (filename, O_RDONLY);
      if (ifd < 0)
	pfatal ("can't open file %s", filename);
      if (read (ifd, buffer, size) != size)
	{
	  /* Perhaps size is too large for this host.  */
	  close (ifd);
	  free (ptr);
	  return FALSE;
	}
      if (close (ifd) != 0)
	read_fatal ();
    }

  /* Scan the buffer and build array of pointers to lines.  */
  iline = 0;
  lim = buffer + size;
  for (s = buffer;  ;  s++)
    {
      ptr[++iline] = s;
      if (! (s = (char *) memchr (s, '\n', lim - s)))
	break;
    }
  if (size && lim[-1] != '\n')
    ptr[++iline] = lim;
  input_lines = iline - 1;

  if (revision)
    {
      char const *rev = revision;
      int rev0 = rev[0];
      int found_revision = 0;
      size_t revlen = strlen (rev);

      if (revlen <= size)
	{
	  char const *limrev = lim - revlen;

	  for (s = buffer;  (s = (char *) memchr (s, rev0, limrev - s));  s++)
	    if (memcmp (s, rev, revlen) == 0
		&& (s == buffer || ISSPACE ((unsigned char) s[-1]))
		&& (s + 1 == limrev || ISSPACE ((unsigned char) s[revlen])))
	      {
		found_revision = 1;
		break;
	      }
	}

      report_revision (found_revision);
    }

  /* Plan A will work.  */
  i_ptr = ptr;
  return TRUE;
}

/* Keep (virtually) nothing in memory. */

static void
plan_b(filename)
     char const *filename;
{
  register FILE *ifp;
  register int c;
  register size_t len;
  register size_t maxlen;
  register int found_revision;
  register size_t i;
  register char const *rev;
  register size_t revlen;
  register LINENUM line;

  if (dry_run)
    filename = "/dev/null";
  if (! (ifp = fopen (filename, "r")))
    pfatal ("can't open file %s", filename);
  tifd = creat (TMPINNAME, S_IRUSR|S_IWUSR|S_IRGRP|S_IWGRP|S_IROTH|S_IWOTH);
  if (tifd < 0)
    pfatal ("can't open file %s", TMPINNAME);
  i = 0;
  len = 0;
  maxlen = 1;
  rev = revision;
  found_revision = !rev;
  revlen = rev ? strlen (rev) : 0;

  while ((c = getc (ifp)) != EOF)
    {
      len++;

      if (c == '\n')
	{
	  if (maxlen < len)
	      maxlen = len;
	  len = 0;
	}

      if (!found_revision)
	{
	  if (i == revlen)
	    {
	      found_revision = ISSPACE ((unsigned char) c);
	      i = (size_t) -1;
	    }
	  else if (i != (size_t) -1)
	    i = rev[i]==c ? i + 1 : (size_t) -1;

	  if (i == (size_t) -1  &&  ISSPACE ((unsigned char) c))
	    i = 0;
	}
    }

  if (revision)
    report_revision (found_revision);
  Fseek (ifp, (off_t) 0, SEEK_SET);		/* rewind file */
  for (tibufsize = TIBUFSIZE_MINIMUM;  tibufsize < maxlen;  tibufsize <<= 1)
    continue;
  lines_per_buf = tibufsize / maxlen;
  tireclen = maxlen;
  tibuf[0] = xmalloc (2 * tibufsize);
  tibuf[1] = tibuf[0] + tibufsize;

  for (line = 1; ; line++)
    {
      char *p = tibuf[0] + maxlen * (line % lines_per_buf);
      char const *p0 = p;
      if (! (line % lines_per_buf))	/* new block */
	if (write (tifd, tibuf[0], tibufsize) != tibufsize)
	  write_fatal ();
      if ((c = getc (ifp)) == EOF)
	break;

      for (;;)
	{
	  *p++ = c;
	  if (c == '\n')
	    {
	      last_line_size = p - p0;
	      break;
	    }

	  if ((c = getc (ifp)) == EOF)
	    {
	      last_line_size = p - p0;
	      line++;
	      goto EOF_reached;
	    }
	}
    }
 EOF_reached:
  if (ferror (ifp)  ||  fclose (ifp) != 0)
    read_fatal ();

  if (line % lines_per_buf  !=  0)
    if (write (tifd, tibuf[0], tibufsize) != tibufsize)
      write_fatal ();
  input_lines = line - 1;
  if (close (tifd) != 0)
    write_fatal ();
  if ((tifd = open (TMPINNAME, O_RDONLY)) < 0)
    pfatal ("can't reopen file %s", TMPINNAME);
}

/* Fetch a line from the input file. */

char const *
ifetch (line, whichbuf, psize)
register LINENUM line;
int whichbuf;				/* ignored when file in memory */
size_t *psize;
{
    register char const *q;
    register char const *p;

    if (line < 1 || line > input_lines) {
	*psize = 0;
	return "";
    }
    if (using_plan_a) {
	p = i_ptr[line];
	*psize = i_ptr[line + 1] - p;
	return p;
    } else {
	LINENUM offline = line % lines_per_buf;
	LINENUM baseline = line - offline;

	if (tiline[0] == baseline)
	    whichbuf = 0;
	else if (tiline[1] == baseline)
	    whichbuf = 1;
	else {
	    tiline[whichbuf] = baseline;
	    if (lseek (tifd, (off_t) (baseline/lines_per_buf * tibufsize),
		       SEEK_SET) == -1
		|| read (tifd, tibuf[whichbuf], tibufsize) < 0)
	      read_fatal ();
	}
	p = tibuf[whichbuf] + (tireclen*offline);
	if (line == input_lines)
	    *psize = last_line_size;
	else {
	    for (q = p;  *q++ != '\n';  )
		continue;
	    *psize = q - p;
	}
	return p;
    }
}