/* Utility functions for finding files relative to GCC binaries.
   Copyright (C) 1992, 1993, 1994, 1995, 1996, 1997, 1998,
   1999, 2000, 2001, 2002, 2003, 2004, 2005, 2007, 2008, 2009, 2010, 2011, 2012

This file is part of GCC.

GCC 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 3, or (at your option) any later
version.

GCC 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 GCC; see the file COPYING3.  If not see
<http://www.gnu.org/licenses/>.  */

#include "config.h"
#include "system.h"
#include "filenames.h"
#include "file-find.h"

static bool debug = false;

void
find_file_set_debug(bool debug_state)
{
  debug = debug_state;
}

char *
find_a_file (struct path_prefix *pprefix, const char *name)
{
  char *temp;
  struct prefix_list *pl;
  int len = pprefix->max_len + strlen (name) + 1;

  if (debug)
    fprintf (stderr, "Looking for '%s'\n", name);

#ifdef HOST_EXECUTABLE_SUFFIX
  len += strlen (HOST_EXECUTABLE_SUFFIX);
#endif

  temp = XNEWVEC (char, len);

  /* Determine the filename to execute (special case for absolute paths).  */

  if (IS_ABSOLUTE_PATH (name))
    {
      if (access (name, X_OK) == 0)
	{
	  strcpy (temp, name);

	  if (debug)
	    fprintf (stderr, "  - found: absolute path\n");

	  return temp;
	}

#ifdef HOST_EXECUTABLE_SUFFIX
	/* Some systems have a suffix for executable files.
	   So try appending that.  */
      strcpy (temp, name);
	strcat (temp, HOST_EXECUTABLE_SUFFIX);

	if (access (temp, X_OK) == 0)
	  return temp;
#endif

      if (debug)
	fprintf (stderr, "  - failed to locate using absolute path\n");
    }
  else
    for (pl = pprefix->plist; pl; pl = pl->next)
      {
	struct stat st;

	strcpy (temp, pl->prefix);
	strcat (temp, name);

	if (stat (temp, &st) >= 0
	    && ! S_ISDIR (st.st_mode)
	    && access (temp, X_OK) == 0)
	  return temp;

#ifdef HOST_EXECUTABLE_SUFFIX
	/* Some systems have a suffix for executable files.
	   So try appending that.  */
	strcat (temp, HOST_EXECUTABLE_SUFFIX);

	if (stat (temp, &st) >= 0
	    && ! S_ISDIR (st.st_mode)
	    && access (temp, X_OK) == 0)
	  return temp;
#endif
      }

  if (debug && pprefix->plist == NULL)
    fprintf (stderr, "  - failed: no entries in prefix list\n");

  free (temp);
  return 0;
}

/* Add an entry for PREFIX to prefix list PPREFIX.  */

void
add_prefix (struct path_prefix *pprefix, const char *prefix)
{
  struct prefix_list *pl, **prev;
  int len;

  if (pprefix->plist)
    {
      for (pl = pprefix->plist; pl->next; pl = pl->next)
	;
      prev = &pl->next;
    }
  else
    prev = &pprefix->plist;

  /* Keep track of the longest prefix.  */

  len = strlen (prefix);
  if (len > pprefix->max_len)
    pprefix->max_len = len;

  pl = XNEW (struct prefix_list);
  pl->prefix = xstrdup (prefix);

  if (*prev)
    pl->next = *prev;
  else
    pl->next = (struct prefix_list *) 0;
  *prev = pl;
}

/* Take the value of the environment variable ENV, break it into a path, and
   add of the entries to PPREFIX.  */

void
prefix_from_env (const char *env, struct path_prefix *pprefix)
{
  const char *p;
  p = getenv (env);

  if (p)
    prefix_from_string (p, pprefix);
}

void
prefix_from_string (const char *p, struct path_prefix *pprefix)
{
  const char *startp, *endp;
  char *nstore = XNEWVEC (char, strlen (p) + 3);

  if (debug)
    fprintf (stderr, "Convert string '%s' into prefixes, separator = '%c'\n", p, PATH_SEPARATOR);

  startp = endp = p;
  while (1)
    {
      if (*endp == PATH_SEPARATOR || *endp == 0)
	{
	  strncpy (nstore, startp, endp-startp);
	  if (endp == startp)
	    {
	      strcpy (nstore, "./");
	    }
	  else if (! IS_DIR_SEPARATOR (endp[-1]))
	    {
	      nstore[endp-startp] = DIR_SEPARATOR;
	      nstore[endp-startp+1] = 0;
	    }
	  else
	    nstore[endp-startp] = 0;

	  if (debug)
	    fprintf (stderr, "  - add prefix: %s\n", nstore);

	  add_prefix (pprefix, nstore);
	  if (*endp == 0)
	    break;
	  endp = startp = endp + 1;
	}
      else
	endp++;
    }
  free (nstore);
}