/* Utility to update paths from internal to external forms.
   Copyright (C) 1997, 1998, 1999, 2000 Free Software Foundation, Inc.

This file is part of GNU CC.

GNU CC is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public
License as published by the Free Software Foundation; either
version 2 of the License, 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
Library General Public License for more details.

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

/* This file contains routines to update a path, both to canonicalize
   the directory format and to handle any prefix translation.

   This file must be compiled with -DPREFIX= to specify the "prefix"
   value used by configure.  If a filename does not begin with this
   prefix, it will not be affected other than by directory canonicalization.

   Each caller of 'update_path' may specify both a filename and
   a translation prefix and consist of the name of the package that contains
   the file ("@GCC", "@BINUTIL", "@GNU", etc).

   If the prefix is not specified, the filename will only undergo
   directory canonicalization.

   If it is specified, the string given by PREFIX will be replaced
   by the specified prefix (with a '@' in front unless the prefix begins
   with a '$') and further translation will be done as follows
   until none of the two conditions below are met:

   1) If the filename begins with '@', the string between the '@' and
   the end of the name or the first '/' or directory separator will
   be considered a "key" and looked up as follows:

   -- If this is a Win32 OS, then the Registry will be examined for
      an entry of "key" in 

      HKEY_LOCAL_MACHINE\SOFTWARE\Free Software Foundation\<KEY>

      if found, that value will be used. <KEY> defaults to GCC version
      string, but can be overridden at configuration time.

   -- If not found (or not a Win32 OS), the environment variable
      key_ROOT (the value of "key" concatenated with the constant "_ROOT")
      is tried.  If that fails, then PREFIX (see above) is used.

   2) If the filename begins with a '$', the rest of the string up
   to the end or the first '/' or directory separator will be used
   as an environment variable, whose value will be returned.

   Once all this is done, any '/' will be converted to DIR_SEPARATOR,
   if they are different. 

   NOTE:  using resolve_keyed_path under Win32 requires linking with
   advapi32.dll.  */


#include "config.h"
#include "system.h"
#if defined(_WIN32) && defined(ENABLE_WIN32_REGISTRY)
#include <windows.h>
#endif
#include "prefix.h"

static const char *std_prefix = PREFIX;

static const char *get_key_value	PARAMS ((char *));
static const char *translate_name	PARAMS ((const char *));
static char *save_string		PARAMS ((const char *, int));

#if defined(_WIN32) && defined(ENABLE_WIN32_REGISTRY)
static char *lookup_key		PARAMS ((char *));
static HKEY reg_key = (HKEY) INVALID_HANDLE_VALUE;
#endif

/* Given KEY, as above, return its value.  */

static const char *
get_key_value (key)
     char *key;
{
  const char *prefix = 0;
  char *temp = 0;

#if defined(_WIN32) && defined(ENABLE_WIN32_REGISTRY)
  prefix = lookup_key (key);
#endif

  if (prefix == 0)
    prefix = getenv (temp = concat (key, "_ROOT", NULL));

  if (prefix == 0)
    prefix = std_prefix;

  if (temp)
    free (temp);

  return prefix;
}

/* Concatenate a sequence of strings, returning the result.

   This function is based on the one in libiberty.  */

char *
concat VPARAMS ((const char *first, ...))
{
  register int length;
  register char *newstr;
  register char *end;
  register const char *arg;
  va_list args;
#ifndef ANSI_PROTOTYPES
  const char *first;
#endif

  /* First compute the size of the result and get sufficient memory.  */

  VA_START (args, first);
#ifndef ANSI_PROTOTYPES
  first = va_arg (args, const char *);
#endif

  arg = first;
  length = 0;

  while (arg != 0)
    {
      length += strlen (arg);
      arg = va_arg (args, const char *);
    }

  newstr = (char *) xmalloc (length + 1);
  va_end (args);

  /* Now copy the individual pieces to the result string.  */

  VA_START (args, first);
#ifndef ANSI_PROTOTYPES
  first = va_arg (args, char *);
#endif

  end = newstr;
  arg = first;
  while (arg != 0)
    {
      while (*arg)
	*end++ = *arg++;
      arg = va_arg (args, const char *);
    }
  *end = '\000';
  va_end (args);

  return (newstr);
}

/* Return a copy of a string that has been placed in the heap.  */

static char *
save_string (s, len)
  const char *s;
  int len;
{
  register char *result = xmalloc (len + 1);

  memcpy (result, s, len);
  result[len] = 0;
  return result;
}

#if defined(_WIN32) && defined(ENABLE_WIN32_REGISTRY)

/* Look up "key" in the registry, as above.  */

static char *
lookup_key (key)
     char *key;
{
  char *dst;
  DWORD size;
  DWORD type;
  LONG res;

  if (reg_key == (HKEY) INVALID_HANDLE_VALUE)
    {
      res = RegOpenKeyExA (HKEY_LOCAL_MACHINE, "SOFTWARE", 0,
			   KEY_READ, &reg_key);

      if (res == ERROR_SUCCESS)
	res = RegOpenKeyExA (reg_key, "Free Software Foundation", 0,
			     KEY_READ, &reg_key);

      if (res == ERROR_SUCCESS)
	res = RegOpenKeyExA (reg_key, WIN32_REGISTRY_KEY, 0,
			     KEY_READ, &reg_key);

      if (res != ERROR_SUCCESS)
        {
          reg_key = (HKEY) INVALID_HANDLE_VALUE;
          return 0;
        }
    }

  size = 32;
  dst = (char *) xmalloc (size);

  res = RegQueryValueExA (reg_key, key, 0, &type, dst, &size);
  if (res == ERROR_MORE_DATA && type == REG_SZ)
    {
      dst = (char *) xrealloc (dst, size);
      res = RegQueryValueExA (reg_key, key, 0, &type, dst, &size);
    }

  if (type != REG_SZ || res != ERROR_SUCCESS)
    {
      free (dst);
      dst = 0;
    }

  return dst;
}
#endif

/* If NAME starts with a '@' or '$', apply the translation rules above
   and return a new name.  Otherwise, return the given name.  */

static const char *
translate_name (name)
  const char *name;
{
  char code = name[0];
  char *key;
  const char *prefix = 0;
  int keylen;

  if (code != '@' && code != '$')
    return name;

  for (keylen = 0;
       (name[keylen + 1] != 0 && !IS_DIR_SEPARATOR (name[keylen + 1]));
       keylen++)
    ;

  key = (char *) alloca (keylen + 1);
  strncpy (key, &name[1], keylen);
  key[keylen] = 0;

  name = &name[keylen + 1];

  if (code == '@')
    {
      prefix = get_key_value (key);
      if (prefix == 0)
	prefix = std_prefix;
    }
  else
    prefix = getenv (key);

  if (prefix == 0)
    prefix = PREFIX;

  /* We used to strip trailing DIR_SEPARATORs here, but that can
     sometimes yield a result with no separator when one was coded
     and intended by the user, causing two path components to run
     together.  */

  return concat (prefix, name, NULL);
}

/* Update PATH using KEY if PATH starts with PREFIX.  */

const char *
update_path (path, key)
  const char *path;
  const char *key;
{
  if (! strncmp (path, std_prefix, strlen (std_prefix)) && key != 0)
    {
      if (key[0] != '$')
	key = concat ("@", key, NULL);

      path = concat (key, &path[strlen (std_prefix)], NULL);

      while (path[0] == '@' || path[0] == '$')
	path = translate_name (path);
    }

#ifdef UPDATE_PATH_HOST_CANONICALIZE
/* Perform host dependant canonicalization when needed.  */
UPDATE_PATH_HOST_CANONICALIZE (path, key);
#endif

#ifdef DIR_SEPARATOR_2
  /* Convert DIR_SEPARATOR_2 to DIR_SEPARATOR. */
  if (DIR_SEPARATOR != DIR_SEPARATOR_2)
    {
      char *new_path = xstrdup (path);
      path = new_path;
      do {
	if (*new_path == DIR_SEPARATOR_2)
	  *new_path = DIR_SEPARATOR;
      } while (*new_path++);
    }
#endif
      
#if defined (DIR_SEPARATOR) && !defined (DIR_SEPARATOR_2)
  if (DIR_SEPARATOR != '/')
    {
      char *new_path = xstrdup (path);
      path = new_path;
      do {
	if (*new_path == '/')
	  *new_path = DIR_SEPARATOR;
      } while (*new_path++);
    }
#endif

  return path;
}

/* Reset the standard prefix */
void
set_std_prefix (prefix, len)
  const char *prefix;
  int len;
{
  std_prefix = save_string (prefix, len);
}