/* patch-header.c - Make C header file suitable for C++.
   Copyright (C) 1993 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; if not, write to the Free Software
Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */

/* This program massages a system include file (such as stdio.h),
   into a form more conformant with ANSI/POSIX, and more suitable for C++:

   * extern "C" { ... } braces are added (inside #ifndef __cplusplus),
   if they seem to be needed.  These prevcnt C++ compilers from name
   mangling the functions inside the braces.

   * If an old-style incomplete function declaration is seen (without
   an argument list), and it is a "standard" function listed in
   the file sys-protos.h (and with a non-empty argument list), then
   the declaration is converted to a complete prototype by replacing
   the empty parameter list with the argument lust from sys-protos.h.

   * The program can be given a list of (names of) required standard
   functions (such as fclose for stdio.h).  If a reqquired function
   is not seen in the input, then a prototype for it will be
   written to the output.

   * If all of the non-comment code of the original file is protected
   against multiple inclusion:
	#ifndef FOO
	#define FOO
	<body of include file>
	#endif
   then extra matter added to the include file is placed inside the <body>.

   * If the input file is OK (nothing needs to be done);
   the output file is not written (nor removed if it exists).

   There are also some special actions that are done for certain
   well-known standard include files:

   * If argv[1] is "sys/stat.h", the Posix.1 macros
   S_ISBLK, S_ISCHR, S_ISDIR, S_ISFIFO, S_ISLNK, S_ISREG are added if
   they were missing, and the corresponding "traditional" S_IFxxx
   macros were defined.

   * If argv[1] is "errno.h", errno is declared if it was missing.

   * TODO:  The input file should be read complete into memory, because:
   a) it needs to be scanned twice anyway, and
   b) it would be nice to allow update in place.

   Usage:
	patch-header FOO.H INFILE.H OUTFILE.H REQUIRED_FUNCS <SCAN-FILE
   where:
   * FOO.H is the relative file name of the include file,
   as it would be #include'd by a C file.  (E.g. stdio.h)
   * INFILE.H is a full pathname for the input file (e.g. /usr/include/stdio.h)
   * OUTFILE.H is the full pathname for where to write the output file,
   if anything needs to be done.  (e.g. ./include/stdio.h)
   * SCAN-FILE is the output of the scan-decls program.
   * REQUIRED_FUNCS is a list of required function (e.g. fclose for stdio.h).

   Written by Per Bothner <bothner@cygnus.com>, July 1993. */

#include <stdio.h>
#include <ctype.h>
#include "obstack.h"
#include "scan.h"

extern char *strcpy();
sstring buf;
int verbose = 0;
int partial_count = 0;
int missing_extern_C_count = 0;
int missing_extra_stuff = 0;

#include "xsys-protos.h"

/* Certain standard files get extra treatment */

enum special_file
{
  no_special,
  errno_special,
  sys_stat_special
};

enum special_file special_file_handling = no_special;

/* The following are only used when handling sys/stat.h */
/* They are set if the corresponding macro has been seen. */
int seen_S_IFBLK = 0, seen_S_ISBLK  = 0;
int seen_S_IFCHR = 0, seen_S_ISCHR  = 0;
int seen_S_IFDIR = 0, seen_S_ISDIR  = 0;
int seen_S_IFIFO = 0, seen_S_ISFIFO = 0;
int seen_S_IFLNK = 0, seen_S_ISLNK  = 0;
int seen_S_IFREG = 0, seen_S_ISREG  = 0;

/* The following are only used when handling errno.h */
int seen_errno = 0;

/* Wrapper around free, to avoid prototype clashes. */

void xfree (ptr)
     char *ptr;
{
  free(ptr);
}

#define obstack_chunk_alloc xmalloc
#define obstack_chunk_free xfree
struct obstack scan_file_obstack;

/* NOTE:  If you edit this, also edit gen-protos.c !! */
struct fn_decl *
lookup_std_proto (name)
     char *name;
{
  int i = hash(name) % HASH_SIZE;
  int i0 = i;
  for (;;)
    {
      struct fn_decl *fn;
      if (hash_tab[i] == 0)
	return NULL;
      fn = &std_protos[hash_tab[i]];
      if (strcmp (fn->fname, name) == 0)
	return fn;
      i = (i+1) % HASH_SIZE;
      if (i == i0)
	abort();
    }
}

char *inc_filename;
int inc_filename_length;
char *progname = "patch-header";
FILE *outf;
sstring buf;
sstring line;

int lbrac_line, rbrac_line;

char **required_functions;
int required_unseen_count;

int 
write_lbrac ()
{
  fprintf (outf, "#ifdef __cplusplus\nextern \"C\" {\n#endif\n");

  if (partial_count)
    {
      fprintf (outf, "#ifndef _PARAMS\n");
      fprintf (outf, "#if defined(__STDC__) || defined(__cplusplus)\n");
      fprintf (outf, "#define _PARAMS(ARGS) ARGS\n");
      fprintf (outf, "#else\n");
      fprintf (outf, "#define _PARAMS(ARGS) ()\n");
      fprintf (outf, "#endif\n#endif /* _PARAMS */\n");
    }
}

struct partial_proto
{
  struct partial_proto *next;
  char *fname;	/* name of function */
  char *rtype;	/* return type */
  struct fn_decl *fn;
  int line_seen;
};

struct partial_proto *partial_proto_list = NULL;

struct partial_proto required_dummy_proto;
#define REQUIRED(FN) ((FN)->partial == &required_dummy_proto)
#define SET_REQUIRED(FN) ((FN)->partial = &required_dummy_proto)
#define CLEAR_REQUIRED(FN) ((FN)->partial = 0)

void
read_scan_file (scan_file)
     FILE *scan_file;
{
  char **rptr;
  int i;
  obstack_init(&scan_file_obstack); 

  for (;;)
    {
      struct partial_proto *partial;
      struct fn_decl *fn;
      int ch;
      char *ptr, *fname, *extern_C, *rtype, *args, *file_seen, *line_seen;
      line.ptr = line.base;
      ch = read_upto (scan_file, &line, '\n');
      if (ch == EOF)
	break;

      fname = line.base;
      for (ptr = fname; *ptr != ';'; ) ptr++;
      *ptr = 0;
      extern_C = ptr + 1;
      for (ptr = extern_C; *ptr != ';'; ) ptr++;
      *ptr = 0;

      if (*extern_C == 'X')
	{
	  switch (special_file_handling)
	    {
	    case errno_special:
	      if (strcmp (fname, "errno") == 0) seen_errno++;
	      break;
	    }
	  continue;
	}

      if (*extern_C == 'M')
	{
	  /* The original include file defines fname as a macro. */
	  fn = lookup_std_proto (fname);

	  /* Since fname is a macro, don't require a prototype for it. */
	  if (fn && REQUIRED (fn))
	    {
	      CLEAR_REQUIRED(fn);
	      required_unseen_count--;
	    }

	  switch (special_file_handling)
	    {
	    case errno_special:
	      if (strcmp (fname, "errno") == 0) seen_errno++;
	      break;
	    case sys_stat_special:
	      if (fname[0] == 'S' && fname[1] == '_')
		{
		  if (strcmp (fname, "S_IFBLK") == 0) seen_S_IFBLK++;
		  else if (strcmp (fname, "S_ISBLK") == 0) seen_S_ISBLK++;
		  else if (strcmp (fname, "S_IFCHR") == 0) seen_S_IFCHR++;
		  else if (strcmp (fname, "S_ISCHR") == 0) seen_S_ISCHR++;
		  else if (strcmp (fname, "S_IFDIR") == 0) seen_S_IFDIR++;
		  else if (strcmp (fname, "S_ISDIR") == 0) seen_S_ISDIR++;
		  else if (strcmp (fname, "S_IFIFO") == 0) seen_S_IFIFO++;
		  else if (strcmp (fname, "S_ISFIFO") == 0) seen_S_ISFIFO++;
		  else if (strcmp (fname, "S_IFLNK") == 0) seen_S_IFLNK++;
		  else if (strcmp (fname, "S_ISLNK") == 0) seen_S_ISLNK++;
		  else if (strcmp (fname, "S_IFREG") == 0) seen_S_IFREG++;
		  else if (strcmp (fname, "S_ISREG") == 0) seen_S_ISREG++;
		}
	      break;
	    }
	  continue;
	}

      rtype = ptr + 1;
      for (ptr = rtype; *ptr != ';'; ) ptr++;
      *ptr = 0;
      args = ptr + 1;
      for (ptr = args; *ptr != ';'; ) ptr++;
      *ptr = 0;
      file_seen = ptr + 1;
      for (ptr = file_seen; *ptr != ';'; ) ptr++;
      *ptr = 0;
      line_seen = ptr + 1;
      for (ptr = line_seen; *ptr != ';'; ) ptr++;
      *ptr = 0;

      if (extern_C[0] == 'f')
	missing_extern_C_count++;

      fn = lookup_std_proto (fname);

      /* Remove the function from the list of required function. */
      if (fn && REQUIRED (fn))
	{
	  CLEAR_REQUIRED(fn);
	  required_unseen_count--;
	}

      /* If we have a full prototype, we're done. */
      if (args[0] != '\0')
	continue;
      
      /* If the partial prototype was included from some other file,
	 we don't need to patch it up (in this run). */
      i = strlen (file_seen);
      if (i < inc_filename_length
	  || strcmp (inc_filename, file_seen + (i - inc_filename_length)) != 0)
	continue;

      if (fn == NULL)
	continue;
      if (fn->fname[0] == '\0' || strcmp(fn->fname, "void") == 0)
	continue;

      /* We only have a partial function declaration,
	 so remember that we have to add a complete prototype. */
      partial_count++;
      partial = (struct partial_proto*)
	obstack_alloc (&scan_file_obstack, sizeof(struct partial_proto));
      partial->fname = obstack_alloc (&scan_file_obstack, strlen(fname) + 1);
      strcpy (partial->fname, fname);
      partial->rtype = obstack_alloc (&scan_file_obstack, strlen(rtype) + 1);
      strcpy (partial->rtype, rtype);
      partial->line_seen = atoi(line_seen);
      partial->fn = fn;
      fn->partial = partial;
      partial->next = partial_proto_list;
      partial_proto_list = partial;
      if (verbose)
	{
	  fprintf (stderr, "(%s: %s non-prototype function declaration.)\n",
		   inc_filename, fname);
	}
    }

  if (missing_extern_C_count + required_unseen_count + partial_count
      + missing_extra_stuff == 0)
    {
      if (verbose)
	fprintf (stderr, "%s: OK, nothing needs to be done.\n", inc_filename);
      exit (0);
    }
  if (required_unseen_count)
    fprintf (stderr, "%s: %d missing function declarations.\n",
	     inc_filename, required_unseen_count);
  if (partial_count)
    fprintf (stderr, "%s: %d non-prototype function declarations.\n",
	     inc_filename, partial_count);
  if (missing_extern_C_count)
    fprintf (stderr, "%s: %d declarations not protected by extern \"C\".\n",
	     inc_filename, missing_extern_C_count);
}

write_rbrac ()
{
  struct fn_decl *fn;
  char **rptr;
  register struct partial_proto *partial;

  if (required_unseen_count)
    fprintf (outf, "#if defined(__STDC__) || defined(__cplusplus)\n");

  /* Now we print out prototypes for those functions that we haven't seen. */
  for (rptr = required_functions; *rptr; rptr++)
    {
      fn = lookup_std_proto (*rptr);
      if (fn == NULL || !REQUIRED (fn))
	continue;
      fprintf (outf, "extern %s %s (%s);\n",
	       fn->rtype, fn->fname, fn->params);
    }
  if (required_unseen_count)
    fprintf (outf,
	     "#endif /* defined(__STDC__) || defined(__cplusplus) */\n");

  switch (special_file_handling)
    {
    case errno_special:
      if (!seen_errno)
	fprintf (outf, "extern int errno;\n");
      break;
    case sys_stat_special:
      if (!seen_S_ISBLK && seen_S_IFBLK)
	fprintf (outf,
		 "#define S_ISBLK(mode) (((mode) & S_IFMT) == S_IFBLK)\n");
      if (!seen_S_ISCHR && seen_S_IFCHR)
	fprintf (outf,
		 "#define S_ISCHR(mode) (((mode) & S_IFMT) == S_IFCHR)\n");
      if (!seen_S_ISDIR && seen_S_IFDIR)
	fprintf (outf,
		 "#define S_ISDIR(mode) (((mode) & S_IFMT) == S_IFDIR)\n");
      if (!seen_S_ISFIFO && seen_S_IFIFO)
	fprintf (outf,
		 "#define S_ISFIFO(mode) (((mode) & S_IFMT) == S_IFIFO)\n");
      if (!seen_S_ISLNK && seen_S_IFLNK)
	fprintf (outf,
		 "#define S_ISLNK(mode) (((mode) & S_IFMT) == S_IFLNK)\n");
      if (!seen_S_ISREG && seen_S_IFREG)
	fprintf (outf,
		 "#define S_ISREG(mode) (((mode) & S_IFMT) == S_IFREG)\n");
      break;
    }


  fprintf (outf, "#ifdef __cplusplus\n}\n#endif\n");
}

char *
strdup (str)
     char *str;
{
  return strcpy((char*)malloc (strlen (str) + 1), str);
}

/* Returns 1 iff the file is properly protected from multiple inclusion:
   #ifndef PROTECT_NAME
   #define PROTECT_NAME
   #endif

 */

int
check_protection (inf, ifndef_line, endif_line)
     FILE *inf;
     int *ifndef_line, *endif_line;
{
  int c;
  int if_nesting = 1; /* Level of nesting of #if's */
  char *protect_name = NULL; /* Identifier following initial #ifndef */
  int define_seen = 0;

  /* Skip initial white space (including comments). */
  for (;; lineno++)
    {
      c = skip_spaces (inf, ' ');
      if (c == EOF)
	return 0;
      if (c != '\n')
	break;
    }
  if (c != '#')
    return 0;
  c = scan_ident (inf, &buf, skip_spaces (inf, ' '));
  if (SSTRING_LENGTH(&buf) == 0 || strcmp (buf.base, "ifndef") != 0)
    return 0;

  /* So far so good: We've seen an initial #ifndef. */
  *ifndef_line = lineno;
  c = scan_ident (inf, &buf, skip_spaces (inf, c));
  if (SSTRING_LENGTH(&buf) == 0 || c == EOF)
    return 0;
  protect_name = strdup (buf.base);

  ungetc (c, inf);
  c = read_upto (inf, &buf, '\n');
  if (c == EOF)
    return 0;
  lineno++;

  for (;;)
    {
      c = skip_spaces(inf, ' ');
      if (c == EOF)
	return 0;
      if (c == '\n')
	{
	  lineno++;
	  continue;
	}
      if (c != '#')
	goto skip_to_eol;
      c = scan_ident (inf, &buf, skip_spaces (inf, ' '));
      if (SSTRING_LENGTH(&buf) == 0)
	;
      else if (!strcmp (buf.base, "ifndef")
	  || !strcmp (buf.base, "ifdef") || !strcmp (buf.base, "if"))
	{
	  if_nesting++;
	}
      else if (!strcmp (buf.base, "endif"))
	{
	  if_nesting--;
	  if (if_nesting == 0)
	    break;
	}
      else if (!strcmp (buf.base, "else"))
	{
	  if (if_nesting == 1)
	    return 0;
	}
      else if (!strcmp (buf.base, "define"))
	{
	  if (if_nesting != 1)
	    goto skip_to_eol;
	  c = skip_spaces (inf, c);
	  c = scan_ident (inf, &buf, c);
	  if (buf.base[0] > 0 && strcmp(buf.base, protect_name) == 0)
	    define_seen = 1;
	}
    skip_to_eol:
      for (;;)
	{
	  if (c == '\n' || c == EOF)
	    break;
	  c = getc (inf);
	}
      if (c == EOF)
	return 0;
      lineno++;
    }

  if (!define_seen)
     return 0;
  *endif_line = lineno;
  /* Skip final white space (including comments). */
  for (;;)
    {
      c = skip_spaces (inf, ' ');
      if (c == EOF)
	break;
      if (c != '\n')
	return 0;
    }

  return 1;
}

int
main(argc, argv)
     int argc;
     char **argv;
{
  FILE *inf;
  int c;
  int i, done;
  char *cptr, *cptr0, **pptr;
  int ifndef_line;
  int endif_line;;


  if (argv[0] && argv[0][0])
    progname = argv[0];

  if (argc < 4)
    {
      fprintf (stderr, "%s: Usage: foo.h infile.h outfile.h req_funcs <scan-file-name\n",
	       progname);
      exit (-1);
    }

  inc_filename = argv[1];
  inc_filename_length = strlen (inc_filename);
  if (strcmp (inc_filename, "sys/stat.h") == 0)
    special_file_handling = sys_stat_special;
  else if (strcmp (inc_filename, "errno.h") == 0)
    special_file_handling = errno_special, missing_extra_stuff++;

  /* Calculate an upper bound of the number of function names in argv[4] */
  for (i = 1, cptr = argv[4]; *cptr; cptr++)
    if (*cptr == ' ') i++;
  /* Find the list of prototypes required for this include file. */ 
  required_functions = (char**)xmalloc((i+1) * sizeof(char*));
  for (cptr = argv[4], cptr0 = cptr, pptr = required_functions, done = 0; 
       !done; cptr++)
    {
      done = *cptr == '\0';
      if (*cptr == ' ' || done)
	{
	  *cptr = '\0';
	  if (cptr > cptr0)
	    {
	      struct fn_decl *fn = lookup_std_proto(cptr0);
	      *pptr++ = cptr0;
	      if (fn == NULL)
		fprintf (stderr, "Internal error:  No prototype for %s\n",
			 cptr0);
	      else
		SET_REQUIRED(fn);
	    }
	  cptr0 = cptr + 1;
	}
    }
  required_unseen_count = pptr - required_functions;
  *pptr = 0;

  read_scan_file (stdin);

  inf = fopen (argv[2], "r");
  if (inf == NULL)
    {
      fprintf (stderr, "%s: Cannot open '%s' for reading -",
	       progname, argv[2]);
      perror (NULL);
      exit (-1);
    }

  outf = fopen (argv[3], "w");
  if (outf == NULL)
    {
      fprintf (stderr, "%s: Cannot open '%s' for writing -",
	       progname, argv[3]);
      perror (NULL);
      exit (-1);
    }

  if (check_protection (inf, &ifndef_line, &endif_line))
    {
#if 0
      fprintf(stderr, "#ifndef %s on line %d; #endif on line %d\n",
	     protect_name, ifndef_line, endif_line);
#endif
      lbrac_line = ifndef_line+1;
      rbrac_line = endif_line;
    }
  else
    {
      lbrac_line = 1;
      rbrac_line = -1;
    }

  fseek(inf, 0, 0);
  lineno = 1;

  for (;;)
    {
      if (lineno == lbrac_line)
	write_lbrac ();
      if (lineno == rbrac_line)
	write_rbrac ();
      for (;;)
	{
	  struct fn_decl *fn;
	  c = getc (inf);
	  if (c == EOF)
	    break;
	  if (isalpha (c) || c == '_')
	    {
	      struct partial_proto *partial;
	      ungetc (c, inf);
	      if (get_token (inf, &buf) != IDENTIFIER_TOKEN)
		abort ();
	      fputs (buf.base, outf);
	      fn = lookup_std_proto (buf.base);
	      /* We only want to edit the declaration matching the one
		 seen by scan-decls, as there can be multiple
		 declarations, selected by #ifdef __STDC__ or whatever. */
	      if (fn && fn->partial && fn->partial->line_seen == lineno)
		{
		  c = skip_spaces (inf, ' ');
		  if (c == EOF)
		    break;
		  if (c == '(')
		    {
		      c = skip_spaces (inf, ' ');
		      if (c == ')')
			{
			  fprintf (outf, " _PARAMS((%s))", fn->params);
			}
		      else
			{
			  putc ('(', outf);
			  ungetc (c, inf);
			}
		    }
		  else
		    putc (c, outf);
		}
	    }
	  else
	    putc (c, outf);
	  if (c == '\n')
	    break;
	}
      if (c == EOF)
	break;
      lineno++;
    }
  if (rbrac_line < 0)
    write_rbrac ();

  fclose (inf);
  fclose (outf);

  return 0;
}
