/* Directory hashing for GNU Make.
Copyright (C) 1988, 89, 91, 92, 93, 94, 95, 96 Free Software Foundation, Inc.
This file is part of GNU Make.

GNU Make 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.

GNU Make 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 GNU Make; see the file COPYING.  If not, write to
the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */

#include "make.h"

#ifdef	HAVE_DIRENT_H
# include <dirent.h>
# define NAMLEN(dirent) strlen((dirent)->d_name)
#else
# define dirent direct
# define NAMLEN(dirent) (dirent)->d_namlen
# ifdef HAVE_SYS_NDIR_H
#  include <sys/ndir.h>
# endif
# ifdef HAVE_SYS_DIR_H
#  include <sys/dir.h>
# endif
# ifdef HAVE_NDIR_H
#  include <ndir.h>
# endif
# ifdef HAVE_VMSDIR_H
#  include "vmsdir.h"
# endif /* HAVE_VMSDIR_H */
#endif

/* In GNU systems, <dirent.h> defines this macro for us.  */
#ifdef _D_NAMLEN
#undef NAMLEN
#define NAMLEN(d) _D_NAMLEN(d)
#endif

#if defined (POSIX) && !defined (__GNU_LIBRARY__)
/* Posix does not require that the d_ino field be present, and some
   systems do not provide it. */
#define REAL_DIR_ENTRY(dp) 1
#define FAKE_DIR_ENTRY(dp)
#else
#define REAL_DIR_ENTRY(dp) (dp->d_ino != 0)
#define FAKE_DIR_ENTRY(dp) (dp->d_ino = 1)
#endif /* POSIX */

#ifdef __MSDOS__
#include <ctype.h>

static char *
dosify (filename)
     char *filename;
{
  static char dos_filename[14];
  char *df;
  int i;

  if (filename == 0)
    return 0;

  if (strpbrk (filename, "\"*+,;<=>?[\\]|") != 0)
    return filename;

  df = dos_filename;

  /* First, transform the name part.  */
  for (i = 0; *filename != '\0' && i < 8 && *filename != '.'; ++i)
    *df++ = tolower (*filename++);

  /* Now skip to the next dot.  */
  while (*filename != '\0' && *filename != '.')
    ++filename;
  if (*filename != '\0')
    {
      *df++ = *filename++;
      for (i = 0; *filename != '\0' && i < 3 && *filename != '.'; ++i)
	*df++ = tolower (*filename++);
    }

  /* Look for more dots.  */
  while (*filename != '\0' && *filename != '.')
    ++filename;
  if (*filename == '.')
    return filename;
  *df = 0;
  return dos_filename;
}
#endif /* __MSDOS__ */

#ifdef VMS

static int
vms_hash (name)
    char *name;
{
  int h = 0;
  int g;

  while (*name)
    {
      h = (h << 4) + *name++;
      g = h & 0xf0000000;
      if (g)
	{
	  h = h ^ (g >> 24);
	  h = h ^ g;
	}
    }
  return h;
}

/* fake stat entry for a directory */
static int
vmsstat_dir (name, st)
    char *name;
    struct stat *st;
{
  char *s;
  int h;
  DIR *dir;

  dir = opendir (name);
  if (dir == 0)
    return -1;
  closedir (dir);
  s = strchr (name, ':');	/* find device */
  if (s)
    {
      *s++ = 0;
      st->st_dev = (char *)vms_hash (name);
    }
  else
    {
      st->st_dev = 0;
      s = name;
    }
  h = vms_hash (s);
  st->st_ino[0] = h & 0xff;
  st->st_ino[1] = h & 0xff00;
  st->st_ino[2] = h >> 16;

  return 0;
}
#endif /* VMS */

/* Hash table of directories.  */

#ifndef	DIRECTORY_BUCKETS
#define DIRECTORY_BUCKETS 199
#endif

struct directory_contents
  {
    struct directory_contents *next;

    dev_t dev;			/* Device and inode numbers of this dir.  */
#ifdef VMS
    ino_t ino[3];
#else
    ino_t ino;
#endif
    struct dirfile **files;	/* Files in this directory.  */
    DIR *dirstream;		/* Stream reading this directory.  */
  };

/* Table of directory contents hashed by device and inode number.  */
static struct directory_contents *directories_contents[DIRECTORY_BUCKETS];

struct directory
  {
    struct directory *next;

    char *name;			/* Name of the directory.  */

    /* The directory's contents.  This data may be shared by several
       entries in the hash table, which refer to the same directory
       (identified uniquely by `dev' and `ino') under different names.  */
    struct directory_contents *contents;
  };

/* Table of directories hashed by name.  */
static struct directory *directories[DIRECTORY_BUCKETS];


/* Never have more than this many directories open at once.  */

#define MAX_OPEN_DIRECTORIES 10

static unsigned int open_directories = 0;


/* Hash table of files in each directory.  */

struct dirfile
  {
    struct dirfile *next;
    char *name;			/* Name of the file.  */
    char impossible;		/* This file is impossible.  */
  };

#ifndef	DIRFILE_BUCKETS
#define DIRFILE_BUCKETS 107
#endif

static int dir_contents_file_exists_p PARAMS ((struct directory_contents *dir, char *filename));
static struct directory *find_directory PARAMS ((char *name));

/* Find the directory named NAME and return its `struct directory'.  */

static struct directory *
find_directory (name)
     register char *name;
{
  register unsigned int hash = 0;
  register char *p;
  register struct directory *dir;
#ifdef VMS
  if ((*name == '.') && (*(name+1) == 0))
    name = "[]";
  else
    name = vmsify (name,1);
#endif

  for (p = name; *p != '\0'; ++p)
    HASH (hash, *p);
  hash %= DIRECTORY_BUCKETS;

  for (dir = directories[hash]; dir != 0; dir = dir->next)
    if (streq (dir->name, name))
      break;

  if (dir == 0)
    {
      struct stat st;

      /* The directory was not found.  Create a new entry for it.  */

      dir = (struct directory *) xmalloc (sizeof (struct directory));
      dir->next = directories[hash];
      directories[hash] = dir;
      dir->name = savestring (name, p - name);

      /* The directory is not in the name hash table.
	 Find its device and inode numbers, and look it up by them.  */

#ifdef VMS
      if (vmsstat_dir (name, &st) < 0)
#else
      if (stat (name, &st) < 0)
#endif
	{
	/* Couldn't stat the directory.  Mark this by
	   setting the `contents' member to a nil pointer.  */
	  dir->contents = 0;
	}
      else
	{
	  /* Search the contents hash table; device and inode are the key.  */

	  struct directory_contents *dc;

#ifdef VMS
	hash = ((unsigned int) st.st_dev << 16)
		| ((unsigned int) st.st_ino[0]
		+ (unsigned int) st.st_ino[1]
		+ (unsigned int) st.st_ino[2]);
#else
	  hash = ((unsigned int) st.st_dev << 16) | (unsigned int) st.st_ino;
#endif
	  hash %= DIRECTORY_BUCKETS;

	  for (dc = directories_contents[hash]; dc != 0; dc = dc->next)
	    if (dc->dev == st.st_dev
#ifdef VMS
		&& dc->ino[0] == st.st_ino[0]
		&& dc->ino[1] == st.st_ino[1]
		&& dc->ino[2] == st.st_ino[2])
#else
		 && dc->ino == st.st_ino)
#endif
	      break;

	  if (dc == 0)
	    {
	      /* Nope; this really is a directory we haven't seen before.  */

	      dc = (struct directory_contents *)
		xmalloc (sizeof (struct directory_contents));

	      /* Enter it in the contents hash table.  */
	      dc->dev = st.st_dev;
#ifdef VMS
	      dc->ino[0] = st.st_ino[0];
	      dc->ino[1] = st.st_ino[1];
	      dc->ino[2] = st.st_ino[2];
#else
	      dc->ino = st.st_ino;
#endif
	      dc->next = directories_contents[hash];
	      directories_contents[hash] = dc;

	      dc->dirstream = opendir (name);
	      if (dc->dirstream == 0)
		{
		/* Couldn't open the directory.  Mark this by
		   setting the `files' member to a nil pointer.  */
		  dc->files = 0;
		}
	      else
		{
		  /* Allocate an array of buckets for files and zero it.  */
		  dc->files = (struct dirfile **)
		    xmalloc (sizeof (struct dirfile *) * DIRFILE_BUCKETS);
		  bzero ((char *) dc->files,
			 sizeof (struct dirfile *) * DIRFILE_BUCKETS);

		  /* Keep track of how many directories are open.  */
		  ++open_directories;
		  if (open_directories == MAX_OPEN_DIRECTORIES)
		    /* We have too many directories open already.
		       Read the entire directory and then close it.  */
		    (void) dir_contents_file_exists_p (dc, (char *) 0);
		}
	    }

	  /* Point the name-hashed entry for DIR at its contents data.  */
	  dir->contents = dc;
	}
    }

  return dir;
}

/* Return 1 if the name FILENAME is entered in DIR's hash table.
   FILENAME must contain no slashes.  */

static int
dir_contents_file_exists_p (dir, filename)
     register struct directory_contents *dir;
     register char *filename;
{
  register unsigned int hash;
  register char *p;
  register struct dirfile *df;
  register struct dirent *d;

  if (dir == 0 || dir->files == 0)
    {
    /* The directory could not be stat'd or opened.  */
      return 0;
    }
#ifdef __MSDOS__
  filename = dosify (filename);
#endif

#ifdef VMS
  filename = vmsify (filename,0);
#endif

  hash = 0;
  if (filename != 0)
    {
      if (*filename == '\0')
	{
	/* Checking if the directory exists.  */
	  return 1;
	}

      for (p = filename; *p != '\0'; ++p)
	HASH (hash, *p);
      hash %= DIRFILE_BUCKETS;

      /* Search the list of hashed files.  */

      for (df = dir->files[hash]; df != 0; df = df->next)
	{
	  if (streq (df->name, filename))
	    {
	      return !df->impossible;
	    }
	}
    }

  /* The file was not found in the hashed list.
     Try to read the directory further.  */

  if (dir->dirstream == 0)
    {
    /* The directory has been all read in.  */
      return 0;
    }

  while ((d = readdir (dir->dirstream)) != 0)
    {
      /* Enter the file in the hash table.  */
      register unsigned int newhash = 0;
      unsigned int len;
      register unsigned int i;

      if (!REAL_DIR_ENTRY (d))
	continue;

      len = NAMLEN (d);
      for (i = 0; i < len; ++i)
	HASH (newhash, d->d_name[i]);
      newhash %= DIRFILE_BUCKETS;

      df = (struct dirfile *) xmalloc (sizeof (struct dirfile));
      df->next = dir->files[newhash];
      dir->files[newhash] = df;
      df->name = savestring (d->d_name, len);
      df->impossible = 0;
      /* Check if the name matches the one we're searching for.  */
      if (filename != 0
	  && newhash == hash && streq (d->d_name, filename))
	{
	  return 1;
	}
    }

  /* If the directory has been completely read in,
     close the stream and reset the pointer to nil.  */
  if (d == 0)
    {
      --open_directories;
      closedir (dir->dirstream);
      dir->dirstream = 0;
    }
  return 0;
}

/* Return 1 if the name FILENAME in directory DIRNAME
   is entered in the dir hash table.
   FILENAME must contain no slashes.  */

int
dir_file_exists_p (dirname, filename)
     register char *dirname;
     register char *filename;
{
  return dir_contents_file_exists_p (find_directory (dirname)->contents,
				     filename);
}

/* Return 1 if the file named NAME exists.  */

int
file_exists_p (name)
     register char *name;
{
  char *dirend;
  char *dirname;

#ifndef	NO_ARCHIVES
  if (ar_name (name))
    return ar_member_date (name) != (time_t) -1;
#endif

#ifdef VMS
  dirend = rindex (name, ']');
  dirend++;
  if (dirend == (char *)1)
    return dir_file_exists_p ("[]", name);
#else
  dirend = rindex (name, '/');
  if (dirend == 0)
    return dir_file_exists_p (".", name);
#endif

  dirname = (char *) alloca (dirend - name + 1);
  bcopy (name, dirname, dirend - name);
  dirname[dirend - name] = '\0';
  return dir_file_exists_p (dirname, dirend + 1);
}

/* Mark FILENAME as `impossible' for `file_impossible_p'.
   This means an attempt has been made to search for FILENAME
   as an intermediate file, and it has failed.  */

void
file_impossible (filename)
     register char *filename;
{
  char *dirend;
  register char *p = filename;
  register unsigned int hash;
  register struct directory *dir;
  register struct dirfile *new;

#ifdef VMS
  dirend = rindex (p, ']');
  dirend++;
  if (dirend == (char *)1)
    dir = find_directory ("[]");
#else
  dirend = rindex (p, '/');
  if (dirend == 0)
    dir = find_directory (".");
#endif
  else
    {
      char *dirname = (char *) alloca (dirend - p + 1);
      bcopy (p, dirname, dirend - p);
      dirname[dirend - p] = '\0';
      dir = find_directory (dirname);
      filename = p = dirend + 1;
    }

  for (hash = 0; *p != '\0'; ++p)
    HASH (hash, *p);
  hash %= DIRFILE_BUCKETS;

  if (dir->contents == 0)
    {
      /* The directory could not be stat'd.  We allocate a contents
	 structure for it, but leave it out of the contents hash table.  */
      dir->contents = (struct directory_contents *)
	xmalloc (sizeof (struct directory_contents));
#ifdef VMS
      dir->contents->dev = 0;
      dir->contents->ino[0] = dir->contents->ino[1] =
	dir->contents->ino[2] = 0;
#else
      dir->contents->dev = dir->contents->ino = 0;
#endif
      dir->contents->files = 0;
      dir->contents->dirstream = 0;
    }

  if (dir->contents->files == 0)
    {
      /* The directory was not opened; we must allocate the hash buckets.  */
      dir->contents->files = (struct dirfile **)
	xmalloc (sizeof (struct dirfile) * DIRFILE_BUCKETS);
      bzero ((char *) dir->contents->files,
	     sizeof (struct dirfile) * DIRFILE_BUCKETS);
    }

  /* Make a new entry and put it in the table.  */

  new = (struct dirfile *) xmalloc (sizeof (struct dirfile));
  new->next = dir->contents->files[hash];
  dir->contents->files[hash] = new;
  new->name = savestring (filename, strlen (filename));
  new->impossible = 1;
}

/* Return nonzero if FILENAME has been marked impossible.  */

int
file_impossible_p (filename)
     char *filename;
{
  char *dirend;
  register char *p = filename;
  register unsigned int hash;
  register struct directory_contents *dir;
  register struct dirfile *next;

#ifdef VMS
  dirend = rindex (filename, ']');
  if (dirend == 0)
    dir = find_directory ("[]")->contents;
#else
  dirend = rindex (filename, '/');
  if (dirend == 0)
    dir = find_directory (".")->contents;
#endif
  else
    {
      char *dirname = (char *) alloca (dirend - filename + 1);
      bcopy (p, dirname, dirend - p);
      dirname[dirend - p] = '\0';
      dir = find_directory (dirname)->contents;
      p = filename = dirend + 1;
    }

  if (dir == 0 || dir->files == 0)
    /* There are no files entered for this directory.  */
    return 0;

#ifdef __MSDOS__
  p = filename = dosify (p);
#endif
#ifdef VMS
  p = filename = vmsify (p, 1);
#endif

  for (hash = 0; *p != '\0'; ++p)
    HASH (hash, *p);
  hash %= DIRFILE_BUCKETS;

  for (next = dir->files[hash]; next != 0; next = next->next)
    if (streq (filename, next->name))
      return next->impossible;

  return 0;
}

/* Return the already allocated name in the
   directory hash table that matches DIR.  */

char *
dir_name (dir)
     char *dir;
{
  return find_directory (dir)->name;
}

/* Print the data base of directories.  */

void
print_dir_data_base ()
{
  register unsigned int i, dirs, files, impossible;
  register struct directory *dir;

  puts ("\n# Directories\n");

  dirs = files = impossible = 0;
  for (i = 0; i < DIRECTORY_BUCKETS; ++i)
    for (dir = directories[i]; dir != 0; dir = dir->next)
      {
	++dirs;
	if (dir->contents == 0)
	  printf ("# %s: could not be stat'd.\n", dir->name);
	else if (dir->contents->files == 0)
#ifdef VMS
	  printf ("# %s (device %d, inode [%d,%d,%d]): could not be opened.\n",
		  dir->name, dir->contents->dev,
		  dir->contents->ino[0], dir->contents->ino[1],
		  dir->contents->ino[2]);
#else
	  printf ("# %s (device %d, inode %d): could not be opened.\n",
		  dir->name, dir->contents->dev, dir->contents->ino);
#endif
	else
	  {
	    register unsigned int f = 0, im = 0;
	    register unsigned int j;
	    register struct dirfile *df;
	    for (j = 0; j < DIRFILE_BUCKETS; ++j)
	      for (df = dir->contents->files[j]; df != 0; df = df->next)
		if (df->impossible)
		  ++im;
		else
		  ++f;
#ifdef VMS
	    printf ("# %s (device %d, inode [%d,%d,%d]): ",
		    dir->name, dir->contents->dev,
			dir->contents->ino[0], dir->contents->ino[1],
			dir->contents->ino[2]);
#else
	    printf ("# %s (device %d, inode %d): ",
		    dir->name, dir->contents->dev, dir->contents->ino);
#endif
	    if (f == 0)
	      fputs ("No", stdout);
	    else
	      printf ("%u", f);
	    fputs (" files, ", stdout);
	    if (im == 0)
	      fputs ("no", stdout);
	    else
	      printf ("%u", im);
	    fputs (" impossibilities", stdout);
	    if (dir->contents->dirstream == 0)
	      puts (".");
	    else
	      puts (" so far.");
	    files += f;
	    impossible += im;
	  }
      }

  fputs ("\n# ", stdout);
  if (files == 0)
    fputs ("No", stdout);
  else
    printf ("%u", files);
  fputs (" files, ", stdout);
  if (impossible == 0)
    fputs ("no", stdout);
  else
    printf ("%u", impossible);
  printf (" impossibilities in %u directories.\n", dirs);
}

/* Hooks for globbing.  */

#include <glob.h>

/* Structure describing state of iterating through a directory hash table.  */

struct dirstream
  {
    struct directory_contents *contents; /* The directory being read.  */

    unsigned int bucket;	/* Current hash bucket.  */
    struct dirfile *elt;	/* Current elt in bucket.  */
  };

/* Forward declarations.  */
static __ptr_t open_dirstream PARAMS ((const char *));
static struct dirent *read_dirstream PARAMS ((__ptr_t));

static __ptr_t
open_dirstream (directory)
     const char *directory;
{
  struct dirstream *new;
  struct directory *dir = find_directory ((char *)directory);

  if (dir->contents == 0 || dir->contents->files == 0)
    /* DIR->contents is nil if the directory could not be stat'd.
       DIR->contents->files is nil if it could not be opened.  */
    return 0;

  /* Read all the contents of the directory now.  There is no benefit
     in being lazy, since glob will want to see every file anyway.  */

  (void) dir_contents_file_exists_p (dir->contents, (char *) 0);

  new = (struct dirstream *) xmalloc (sizeof (struct dirstream));
  new->contents = dir->contents;
  new->bucket = 0;
  new->elt = new->contents->files[0];

  return (__ptr_t) new;
}

static struct dirent *
read_dirstream (stream)
     __ptr_t stream;
{
  struct dirstream *const ds = (struct dirstream *) stream;
  register struct dirfile *df;
  static char *buf;
  static unsigned int bufsz;

  while (ds->bucket < DIRFILE_BUCKETS)
    {
      while ((df = ds->elt) != 0)
	{
	  ds->elt = df->next;
	  if (!df->impossible)
	    {
	      /* The glob interface wants a `struct dirent',
		 so mock one up.  */
	      struct dirent *d;
	      unsigned int len = strlen (df->name) + 1;
	      if (sizeof *d - sizeof d->d_name + len > bufsz)
		{
		  if (buf != 0)
		    free (buf);
		  bufsz *= 2;
		  if (sizeof *d - sizeof d->d_name + len > bufsz)
		    bufsz = sizeof *d - sizeof d->d_name + len;
		  buf = xmalloc (bufsz);
		}
	      d = (struct dirent *) buf;
	      FAKE_DIR_ENTRY (d);
#ifdef _DIRENT_HAVE_D_NAMLEN
	      d->d_namlen = len - 1;
#endif
	      memcpy (d->d_name, df->name, len);
	      return d;
	    }
	}
      if (++ds->bucket == DIRFILE_BUCKETS)
	break;
      ds->elt = ds->contents->files[ds->bucket];
    }

  return 0;
}

void
dir_setup_glob (gl)
     glob_t *gl;
{
  extern int stat ();

  /* Bogus sunos4 compiler complains (!) about & before functions.  */
  gl->gl_opendir = open_dirstream;
  gl->gl_readdir = read_dirstream;
  gl->gl_closedir = free;
  gl->gl_stat = stat;
  /* We don't bother setting gl_lstat, since glob never calls it.
     The slot is only there for compatibility with 4.4 BSD.  */
}