/* Copyright (C) 1993, 2000 artofcode LLC.  All rights reserved.
  
  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 of the License, 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, Inc.,
  59 Temple Place, Suite 330, Boston, MA, 02111-1307.

*/

/*$Id: gp_unifs.c,v 1.6.2.2.2.1 2003/01/17 00:49:02 giles Exp $ */
/* "Unix-like" file system platform routines for Ghostscript */
#include "memory_.h"
#include "string_.h"
#include "gx.h"
#include "gp.h"
#include "gpmisc.h"
#include "gsstruct.h"
#include "gsutil.h"		/* for string_match */
#include "stat_.h"
#include "dirent_.h"
#include "unistd_.h"
#include <stdlib.h>             /* for mkstemp/mktemp */
#include <sys/param.h>		/* for MAXPATHLEN */

/* Some systems (Interactive for example) don't define MAXPATHLEN,
 * so we define it here.  (This probably should be done via a Config-Script.)
 */

#ifndef MAXPATHLEN
#  define MAXPATHLEN 1024
#endif

/* Library routines not declared in a standard header */
extern char *mktemp(P1(char *));

/* ------ File naming and accessing ------ */

/* Define the default scratch file name prefix. */
const char gp_scratch_file_name_prefix[] = "gs_";

/* Define the name of the null output file. */
const char gp_null_file_name[] = "/dev/null";

/* Define the name that designates the current directory. */
const char gp_current_directory_name[] = ".";

/* Create and open a scratch file with a given name prefix. */
/* Write the actual file name at fname. */
FILE *
gp_open_scratch_file(const char *prefix, char fname[gp_file_name_sizeof],
		     const char *mode)
{	/* The -8 is for XXXXXX plus a possible final / and -. */
    int prefix_length = strlen(prefix);
    int len = gp_file_name_sizeof - prefix_length - 8;

    if (gp_pathstring_not_bare(prefix, prefix_length))
	*fname = 0;
    else if (gp_gettmpdir(fname, &len) != 0)
	strcpy(fname, "/tmp/");
    else {
	if (strlen(fname) != 0 && fname[strlen(fname) - 1] != '/')
	    strcat(fname, "/");
    }
    if (strlen(fname) + prefix_length + 8 >= gp_file_name_sizeof)
	return 0;		/* file name too long */
    strcat(fname, prefix);
    /* Prevent trailing X's in path from being converted by mktemp. */
    if (*fname != 0 && fname[strlen(fname) - 1] == 'X')
	strcat(fname, "-");
    strcat(fname, "XXXXXX");

#ifdef HAVE_MKSTEMP
    {
	    int file;
	    FILE *fp;

	    file = mkstemp(fname);
	    if (file < -1)
		    return NULL;
	    fp = fdopen(file, mode);
	    if (fp == NULL)
		    close(file);
		    
	    return fp;
    }
#else
    mktemp(fname);
    return gp_fopentemp(fname, mode);
#endif
}

/* Open a file with the given name, as a stream of uninterpreted bytes. */
FILE *
gp_fopen(const char *fname, const char *mode)
{
    return fopen(fname, mode);
}

/* Set a file into binary or text mode. */
int
gp_setmode_binary(FILE * pfile, bool mode)
{
    return 0;			/* Noop under Unix */
}

/* ------ File enumeration ------ */

/* Thanks to Fritz Elfert (Fritz_Elfert@wue.maus.de) for */
/* the original version of the following code, and Richard Mlynarik */
/* (mly@adoc.xerox.com) for an improved version. */

typedef struct dirstack_s dirstack;
struct dirstack_s {
    dirstack *next;
    DIR *entry;
};

gs_private_st_ptrs1(st_dirstack, dirstack, "dirstack",
		    dirstack_enum_ptrs, dirstack_reloc_ptrs, next);

struct file_enum_s {
    DIR *dirp;			/* pointer to current open directory   */
    char *pattern;		/* original pattern                    */
    char *work;			/* current path                        */
    int worklen;		/* strlen (work)                       */
    dirstack *dstack;		/* directory stack                     */
    int patlen;
    int pathead;		/* how much of pattern to consider
				 *  when listing files in current directory */
    bool first_time;
    gs_memory_t *memory;
};
gs_private_st_ptrs3(st_file_enum, struct file_enum_s, "file_enum",
	  file_enum_enum_ptrs, file_enum_reloc_ptrs, pattern, work, dstack);

/* Private procedures */

/* Do a wild-card match. */
#ifdef DEBUG
private bool
wmatch(const byte * str, uint len, const byte * pstr, uint plen,
       const string_match_params * psmp)
{
    bool match = string_match(str, len, pstr, plen, psmp);

    if (gs_debug_c('e')) {
	int i;
	dlputs("[e]string_match(\"");
	for (i=0; i<len; i++)
	    errprintf("%c", str[i]);
	dputs("\", \"");
	for (i=0; i<plen; i++)
	    errprintf("%c", pstr[i]);
	dprintf1("\") = %s\n", (match ? "TRUE" : "false"));
    }
    return match;
}
#define string_match wmatch
#endif

/* Search a string backward for a character. */
/* (This substitutes for strrchr, which some systems don't provide.) */
private char *
rchr(char *str, char ch, int len)
{
    register char *p = str + len;

    while (p > str)
	if (*--p == ch)
	    return p;
    return 0;
}

/* Pop a directory from the enumeration stack. */
private bool
popdir(file_enum * pfen)
{
    dirstack *d = pfen->dstack;

    if (d == 0)
	return false;
    pfen->dirp = d->entry;
    pfen->dstack = d->next;
    gs_free_object(pfen->memory, d, "gp_enumerate_files(popdir)");
    return true;
}

/* Initialize an enumeration. */
file_enum *
gp_enumerate_files_init(const char *pat, uint patlen, gs_memory_t * mem)
{
    file_enum *pfen;
    char *p;
    char *work;

    /* Reject attempts to enumerate paths longer than the */
    /* system-dependent limit. */
    if (patlen > MAXPATHLEN)
	return 0;

    /* Reject attempts to enumerate with a pattern containing zeroes. */
    {
	const char *p1;

	for (p1 = pat; p1 < pat + patlen; p1++)
	    if (*p1 == 0)
		return 0;
    }
    /* >>> Should crunch strings of repeated "/"'s in pat to a single "/"
     * >>>  to match stupid unix filesystem "conventions" */

    pfen = gs_alloc_struct(mem, file_enum, &st_file_enum,
			   "gp_enumerate_files");
    if (pfen == 0)
	return 0;

    /* pattern and work could be allocated as strings, */
    /* but it's simpler for GC and freeing to allocate them as bytes. */

    pfen->pattern =
	(char *)gs_alloc_bytes(mem, patlen + 1,
			       "gp_enumerate_files(pattern)");
    if (pfen->pattern == 0)
	return 0;
    memcpy(pfen->pattern, pat, patlen);
    pfen->pattern[patlen] = 0;

    work = (char *)gs_alloc_bytes(mem, MAXPATHLEN + 1,
				  "gp_enumerate_files(work)");
    if (work == 0)
	return 0;
    pfen->work = work;

    p = work;
    memcpy(p, pat, patlen);
    p += patlen;
    *p = 0;

    /* Remove directory specifications beyond the first wild card. */
    /* Some systems don't have strpbrk, so we code it open. */
    p = pfen->work;
    while (!(*p == '*' || *p == '?' || *p == 0))
	p++;
    while (!(*p == '/' || *p == 0))
	p++;
    if (*p == '/')
	*p = 0;
    /* Substring for first wildcard match */
    pfen->pathead = p - work;

    /* Select the next higher directory-level. */
    p = rchr(work, '/', p - work);
    if (!p) {			/* No directory specification */
	work[0] = 0;
	pfen->worklen = 0;
    } else {
	if (p == work) {	/* Root directory -- don't turn "/" into "" */
	    p++;
	}
	*p = 0;
	pfen->worklen = p - work;
    }

    pfen->memory = mem;
    pfen->dstack = 0;
    pfen->first_time = true;
    pfen->patlen = patlen;
    return pfen;
}

/* Enumerate the next file. */
uint
gp_enumerate_files_next(file_enum * pfen, char *ptr, uint maxlen)
{
    const dir_entry *de;
    char *work = pfen->work;
    int worklen = pfen->worklen;
    char *pattern = pfen->pattern;
    int pathead = pfen->pathead;
    int len;
    struct stat stbuf;

    if (pfen->first_time) {
	pfen->dirp = ((worklen == 0) ? opendir(".") : opendir(work));
	if_debug1('e', "[e]file_enum:First-Open '%s'\n", work);
	pfen->first_time = false;
	if (pfen->dirp == 0) {	/* first opendir failed */
	    gp_enumerate_files_close(pfen);
	    return ~(uint) 0;
	}
    }
  top:de = readdir(pfen->dirp);
    if (de == 0) {		/* No more entries in this directory */
	char *p;

	if_debug0('e', "[e]file_enum:Closedir\n");
	closedir(pfen->dirp);
	/* Back working directory and matching pattern up one level */
	p = rchr(work, '/', worklen);
	if (p != 0) {
	    if (p == work)
		p++;
	    *p = 0;
	    worklen = p - work;
	} else
	    worklen = 0;
	p = rchr(pattern, '/', pathead);
	if (p != 0)
	    pathead = p - pattern;
	else
	    pathead = 0;

	if (popdir(pfen)) {	/* Back up the directory tree. */
	    if_debug1('e', "[e]file_enum:Dir popped '%s'\n", work);
	    goto top;
	} else {
	    if_debug0('e', "[e]file_enum:Dirstack empty\n");
	    gp_enumerate_files_close(pfen);
	    return ~(uint) 0;
	}
    }
    /* Skip . and .. */
    len = strlen(de->d_name);
    if (len <= 2 && (!strcmp(de->d_name, ".") || !strcmp(de->d_name, "..")))
	goto top;
    if (len + worklen + 1 > MAXPATHLEN)
	/* Should be an error, I suppose */
	goto top;
    if (worklen == 0) {		/* "Current" directory (evil un*x kludge) */
	memcpy(work, de->d_name, len + 1);
    } else if (worklen == 1 && work[0] == '/') {	/* Root directory */
	memcpy(work + 1, de->d_name, len + 1);
	len = len + 1;
    } else {
	work[worklen] = '/';
	memcpy(work + worklen + 1, de->d_name, len + 1);
	len = worklen + 1 + len;
    }

    /* Test for a match at this directory level */
    if (!string_match((byte *) work, len, (byte *) pattern, pathead, NULL))
	goto top;

    /* Perhaps descend into subdirectories */
    if (pathead < pfen->patlen) {
	DIR *dp;

	if (((stat(work, &stbuf) >= 0)
	     ? !stat_is_dir(stbuf)
	/* Couldn't stat it.
	 * Well, perhaps it's a directory and
	 * we'll be able to list it anyway.
	 * If it isn't or we can't, no harm done. */
	     : 0))
	    goto top;

	if (pfen->patlen == pathead + 1) {	/* Listing "foo/?/" -- return this entry */
	    /* if it's a directory. */
	    if (!stat_is_dir(stbuf)) {	/* Do directoryp test the hard way */
		dp = opendir(work);
		if (!dp)
		    goto top;
		closedir(dp);
	    }
	    work[len++] = '/';
	    goto winner;
	}
	/* >>> Should optimise the case in which the next level */
	/* >>> of directory has no wildcards. */
	dp = opendir(work);
#ifdef DEBUG
	{
	    char save_end = pattern[pathead];

	    pattern[pathead] = 0;
	    if_debug2('e', "[e]file_enum:fname='%s', p='%s'\n",
		      work, pattern);
	    pattern[pathead] = save_end;
	}
#endif /* DEBUG */
	if (!dp)
	    /* Can't list this one */
	    goto top;
	else {			/* Advance to the next directory-delimiter */
	    /* in pattern */
	    char *p;
	    dirstack *d;

	    for (p = pattern + pathead + 1;; p++) {
		if (*p == 0) {	/* No more subdirectories to match */
		    pathead = pfen->patlen;
		    break;
		} else if (*p == '/') {
		    pathead = p - pattern;
		    break;
		}
	    }

	    /* Push a directory onto the enumeration stack. */
	    d = gs_alloc_struct(pfen->memory, dirstack,
				&st_dirstack,
				"gp_enumerate_files(pushdir)");
	    if (d != 0) {
		d->next = pfen->dstack;
		d->entry = pfen->dirp;
		pfen->dstack = d;
	    } else
		DO_NOTHING;	/* >>> e_VMerror!!! */

	    if_debug1('e', "[e]file_enum:Dir pushed '%s'\n",
		      work);
	    worklen = len;
	    pfen->dirp = dp;
	    goto top;
	}
    }
  winner:
    /* We have a winner! */
    pfen->worklen = worklen;
    pfen->pathead = pathead;
    memcpy(ptr, work, len);
    return len;
}

/* Clean up the file enumeration. */
void
gp_enumerate_files_close(file_enum * pfen)
{
    gs_memory_t *mem = pfen->memory;

    if_debug0('e', "[e]file_enum:Cleanup\n");
    while (popdir(pfen))	/* clear directory stack */
	DO_NOTHING;
    gs_free_object(mem, (byte *) pfen->work,
		   "gp_enumerate_close(work)");
    gs_free_object(mem, (byte *) pfen->pattern,
		   "gp_enumerate_files_close(pattern)");
    gs_free_object(mem, pfen, "gp_enumerate_files_close");
}

/* Test-cases:
   (../?*r*?/?*.ps) {==} 100 string filenameforall
   (../?*r*?/?*.ps*) {==} 100 string filenameforall
   (../?*r*?/) {==} 100 string filenameforall
   (/t*?/?*.ps) {==} 100 string filenameforall
 */