// mapfile.c - associative array interface to external files

//

// © Portions Copyright (c) Symbian Software Ltd 2007. All rights reserved.

//

/*

 * This file is part of zsh, the Z shell.

 *

 * Copyright (c) 1999 Sven Wischnowsky, Peter Stephenson

 * All rights reserved.

 *

 * Permission is hereby granted, without written agreement and without

 * license or royalty fees, to use, copy, modify, and distribute this

 * software and to distribute modified versions of this software for any

 * purpose, provided that the above copyright notice and the following

 * two paragraphs appear in all copies of this software.

 *

 * In no event shall Sven Wischnowsky, Peter Stephenson or the Zsh Development

 * Group be liable to any party for direct, indirect, special, incidental, or

 * consequential damages arising out of the use of this software and its

 * documentation, even if Peter Stephenson, Sven Wischnowsky and the Zsh

 * Development Group have been advised of the possibility of such damage.

 *

 * Peter Stephenson, Sven Wischnowsky and the Zsh Development Group

 * specifically disclaim any warranties, including, but not limited to, the

 * implied warranties of merchantability and fitness for a particular purpose.

 * The softwareprovided hereunder is on an "as is" basis, and Peter

 * Stephenson, Sven Wischnowsky and the Zsh Development Group have no

 * obligation to provide maintenance, support, updates, enhancements, or

 * modifications. 

 *

 */

/*

 * To do:  worry about when keys of associative arrays get unmeta'd.

 */

#include "mapfile.mdh"

#include "mapfile.pro"

/*

 * Make sure we have all the bits I'm using for memory mapping, otherwise

 * I don't know what I'm doing.

 */

#if defined(HAVE_SYS_MMAN_H) && defined(HAVE_FTRUNCATE)

#if defined(HAVE_MMAP) && defined(HAVE_MUNMAP) && defined(HAVE_MSYNC)

#define USE_MMAP 1

#include <sys/mman.h>

#if !defined(MAP_VARIABLE)

#define MAP_VARIABLE 0

#endif

#if !defined(MAP_FILE)

#define MAP_FILE 0

#endif

#if !defined(MAP_NORESERVE)

#define MAP_NORESERVE 0

#endif

#define MMAP_ARGS (MAP_FILE | MAP_VARIABLE | MAP_SHARED | MAP_NORESERVE)

#endif /* HAVE_MMAP && HAVE_MUNMAP && HAVE_MSYNC */

#endif /* HAVE_SYS_MMAN_H &&  HAVE_FTRUNCATE */

#ifdef __SYMBIAN32__

#ifdef __WINSCW__

#pragma warn_unusedarg off

#endif//__WINSCW__

#endif//__SYMBIAN32__

/*

 * Name of the special parameter.  If zmodload took arguments,

 * we could make this selectable.

 */

static char mapfile_nam[] = "mapfile";

static Param mapfile_pm;

/* Empty dummy function for special hash parameters. */

/**/

static void

shempty(void)

{

}

static const struct gsu_hash mapfiles_gsu =

{ hashgetfn, setpmmapfiles, stdunsetfn };

/* Create the special hash parameter. */

/**/

static Param

createmapfilehash()

{

    Param pm;

    HashTable ht;

    unsetparam(mapfile_nam);

    mapfile_pm = NULL;

    if (!(pm = createparam(mapfile_nam, PM_SPECIAL|PM_HIDE|PM_HIDEVAL|

			   PM_REMOVABLE|PM_HASHED)))

	return NULL;

    pm->level = pm->old ? locallevel : 0;

    pm->gsu.h = &mapfiles_gsu;

    pm->u.hash = ht = newhashtable(7, mapfile_nam, NULL);

    ht->hash        = hasher;

    ht->emptytable  = (TableFunc) shempty;

    ht->filltable   = NULL;

    ht->addnode     = (AddNodeFunc) shempty;

    ht->getnode     = ht->getnode2 = getpmmapfile;

    ht->removenode  = (RemoveNodeFunc) shempty;

    ht->disablenode = NULL;

    ht->enablenode  = NULL;

    ht->freenode    = (FreeNodeFunc) shempty;

    ht->printnode   = printparamnode;

    ht->scantab     = scanpmmapfile;

    return (mapfile_pm = pm);

}

/* Functions for the options special parameter. */

/**/

static void

setpmmapfile(Param pm, char *value)

{

    int fd = -1, len;

    char *name = ztrdup(pm->nam);

#ifdef USE_MMAP

    caddr_t mmptr;

#else

    FILE *fout;

#endif

    /*

     * First unmetafy the value, and the name since we don't

     * where it's been.

     */

    unmetafy(name, &len);

    unmetafy(value, &len);

    /* Open the file for writing */

#ifdef USE_MMAP

    if (!(pm->flags & PM_READONLY) &&

	(fd = open(name, O_RDWR|O_CREAT|O_NOCTTY, 0666)) >= 0 &&

	(mmptr = (caddr_t)mmap((caddr_t)0, len, PROT_READ | PROT_WRITE,

			       MMAP_ARGS, fd, (off_t)0)) != (caddr_t)-1) {

	/*

	 * First we need to make sure the file is long enough for

	 * when we msync.  On AIX, at least, we just get zeroes otherwise.

	 */

	ftruncate(fd, len);

	memcpy(mmptr, value, len);

#ifndef MS_SYNC

#define MS_SYNC 0

#endif

	msync(mmptr, len, MS_SYNC);

	/*

	 * Then we need to truncate again, since mmap() always maps complete

	 * pages.  Honestly, I tried it without, and you need both.

	 */

	ftruncate(fd, len);

	munmap(mmptr, len);

    }

#else /* don't USE_MMAP */

    /* can't be bothered to do anything too clever here */

    if ((fout = fopen(name, "w"))) {

	while (len--)

	    putc(*value++, fout);

	fclose(fout);

    }

#endif /* USE_MMAP */

    if (fd >= 0)

	close(fd);

    free(name);

    free(value);

}

/**/

static void

unsetpmmapfile(Param pm, UNUSED(int exp))

{

    /* Unlink the file given by pm->nam */

    char *fname = ztrdup(pm->nam);

    int dummy;

    unmetafy(fname, &dummy);

    if (!(pm->flags & PM_READONLY))

	unlink(fname);

    free(fname);

}

/**/

static void

setpmmapfiles(Param pm, HashTable ht)

{

    int i;

    HashNode hn;

    /* just to see if I've understood what's happening */

    DPUTS(pm != mapfile_pm, "BUG: setpmmapfiles called for wrong param");

    if (!ht)

	return;

    if (!(pm->flags & PM_READONLY))

	for (i = 0; i < ht->hsize; i++)

	    for (hn = ht->nodes[i]; hn; hn = hn->next) {

		struct value v;

		v.isarr = v.inv = v.start = 0;

		v.end = -1;

		v.arr = NULL;

		v.pm = (Param) hn;

		setpmmapfile(v.pm, ztrdup(getstrvalue(&v)));

	    }

    deleteparamtable(ht);

}

/**/

static char *

get_contents(char *fname)

{

    int fd;

#ifdef USE_MMAP

    caddr_t mmptr;

    struct stat sbuf;

#endif

    char *val;

    unmetafy(fname = ztrdup(fname), &fd);

#ifdef USE_MMAP

    if ((fd = open(fname, O_RDONLY | O_NOCTTY)) < 0 ||

	fstat(fd, &sbuf) ||

	(mmptr = (caddr_t)mmap((caddr_t)0, sbuf.st_size, PROT_READ,

			       MMAP_ARGS, fd, (off_t)0)) == (caddr_t)-1) {

	if (fd >= 0)

	    close(fd);

	free(fname);

	return NULL;

    }

    /*

     * Sadly, we need to copy the thing even if metafying doesn't

     * change it.  We just don't know when we might get a chance to

     * munmap it, otherwise.

     */

    val = metafy((char *)mmptr, sbuf.st_size, META_HEAPDUP);

    munmap(mmptr, sbuf.st_size);

    close(fd);

#else /* don't USE_MMAP */

    val = NULL;

    if ((fd = open(fname, O_RDONLY | O_NOCTTY)) >= 0) {

	LinkList ll;

	if ((ll = readoutput(fd, 1)))

	    val = peekfirst(ll);

    }

#endif /* USE_MMAP */

    free(fname);

    return val;

}

static const struct gsu_scalar mapfile_gsu =

{ strgetfn, setpmmapfile, unsetpmmapfile };

/**/

static HashNode

getpmmapfile(UNUSED(HashTable ht), char *name)

{

    char *contents;

    Param pm = NULL;

    pm = (Param) hcalloc(sizeof(struct param));

    pm->nam = dupstring(name);

    pm->flags = PM_SCALAR;

    pm->gsu.s = &mapfile_gsu;

    pm->flags |= (mapfile_pm->flags & PM_READONLY);

    /* Set u.str to contents of file given by name */

    if ((contents = get_contents(pm->nam)))

	pm->u.str = contents;

    else {

	pm->u.str = "";

	pm->flags |= PM_UNSET;

    }

    return (HashNode) pm;

}

/**/

static void

scanpmmapfile(UNUSED(HashTable ht), ScanFunc func, int flags)

{

    struct param pm;

    DIR *dir;

    if (!(dir = opendir(".")))

	return;

    memset((void *)&pm, 0, sizeof(struct param));

    pm.flags = PM_SCALAR;

    pm.gsu.s = &mapfile_gsu;

    pm.flags |= (mapfile_pm->flags & PM_READONLY);

    /* Here we scan the current directory, calling func() for each file */

    while ((pm.nam = zreaddir(dir, 1))) {

	/*

	 * Hmmm, it's rather wasteful always to read the contents.

	 * In fact, it's grotesequely wasteful, since that would mean

	 * we always read the entire contents of every single file

	 * in the directory into memory.  Hence just leave it empty.

	 */

	pm.nam = dupstring(pm.nam);

	pm.u.str = "";

	func((HashNode) &pm, flags);

    }

    closedir(dir);

}

/**/

int

setup_(UNUSED(Module m))

{

    return 0;

}

/**/

int

boot_(UNUSED(Module m))

{

    /* Create the special associative array. */

    if (!createmapfilehash())

	return 1;

    return 0;

}

/**/

int

cleanup_(UNUSED(Module m))

{

    Param pm;

    /* Remove the special parameter if it is still the same. */

    if ((pm = (Param) paramtab->getnode(paramtab, mapfile_nam)) &&

	pm == mapfile_pm) {

	pm->flags &= ~PM_READONLY;

	unsetparam_pm(pm, 0, 1);

    }

    return 0;

}

/**/

int

finish_(UNUSED(Module m))

{

    return 0;

}