r3082: Bugfix: If no pinboard or panel icons were present, the menu could not be

[rox-filer.git] / ROX-Filer / src / support.c

/*
 * $Id$
 *
 * ROX-Filer, filer for the ROX desktop project
 * Copyright (C) 2003, the ROX-Filer team.
 *
 * 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  USA
 */

/* support.c - (non-GUI) useful routines */

#include "config.h"

#include <stdio.h>
#include <stdlib.h>
#include <netdb.h>
#include <errno.h>
#include <ctype.h>
#include <sys/param.h>
#include <pwd.h>
#include <grp.h>
#include <fcntl.h>
#include <sys/wait.h>
#include <string.h>
#include <time.h>
#include <unistd.h>
#include <libxml/parser.h>
#include <math.h>

#include "global.h"

#include "choices.h"
#include "main.h"
#include "options.h"
#include "support.h"
#include "fscache.h"
#include "main.h"
#include "xml.h"

static GHashTable *uid_hash = NULL;     /* UID -> User name */
static GHashTable *gid_hash = NULL;     /* GID -> Group name */

/* Static prototypes */
static void MD5Transform(guint32 buf[4], guint32 const in[16]);

/****************************************************************
 *                      EXTERNAL INTERFACE                      *
 ****************************************************************/

/* g_object_unref() the result! */
XMLwrapper *xml_cache_load(const gchar *pathname)
{
        static GFSCache *xml_cache = NULL;

        if (!xml_cache)
                xml_cache = g_fscache_new((GFSLoadFunc) xml_new, NULL, NULL);
        return g_fscache_lookup(xml_cache, pathname);
}

/* Save doc as XML as filename, 0 on success or 1 on failure */
int save_xml_file(xmlDocPtr doc, const gchar *filename)
{
#if LIBXML_VERSION > 20400
        if (xmlSaveFormatFileEnc(filename, doc, NULL, 1) < 0)
                return 1;
#else
        FILE *out;
        
        out = fopen(filename, "w");
        if (!out)
                return 1;

        xmlDocDump(out, doc);  /* Some versions return void */

        if (fclose(out))
                return 1;
#endif

        return 0;
}

/* Create a new SOAP message and return the document and the (empty)
 * body node.
 */
xmlDocPtr soap_new(xmlNodePtr *ret_body)
{
        xmlDocPtr  doc;
        xmlNodePtr root;
        xmlNs      *env_ns;

        doc = xmlNewDoc("1.0");
        root = xmlNewDocNode(doc, NULL, "Envelope", NULL);
        xmlDocSetRootElement(doc, root);
        
        env_ns = xmlNewNs(root, SOAP_ENV_NS, "env");
        xmlSetNs(root, env_ns);

        *ret_body = xmlNewTextChild(root, env_ns, "Body", NULL);
        xmlNewNs(*ret_body, ROX_NS, "rox");

        return doc;
}

/* Like g_strdup, but does realpath() too (if possible) */
char *pathdup(const char *path)
{
        char real[MAXPATHLEN];

        g_return_val_if_fail(path != NULL, NULL);

        if (realpath(path, real))
                return g_strdup(real);

        return g_strdup(path);
}

/* Join the path to the leaf (adding a / between them) and
 * return a pointer to a static buffer with the result. Buffer is valid
 * until the next call to make_path.
 * The return value may be used as 'dir' for the next call.
 */
const guchar *make_path(const char *dir, const char *leaf)
{
        static GString *buffer = NULL;

        if (!buffer)
                buffer = g_string_new(NULL);

        g_return_val_if_fail(dir != NULL, buffer->str);
        g_return_val_if_fail(leaf != NULL, buffer->str);

        if (buffer->str != dir)
                g_string_assign(buffer, dir);

        if (dir[0] != '/' || dir[1] != '\0')
                g_string_append_c(buffer, '/'); /* For anything except "/" */

        g_string_append(buffer, leaf);

        return buffer->str;
}

/* Return our complete host name for DND */
const char *our_host_name_for_dnd(void)
{
        if (o_dnd_no_hostnames.int_value)
                return "";
        return our_host_name();
}

/* Return our complete host name, unconditionally */
const char *our_host_name(void)
{
        static char *name = NULL;

        if (!name)
        {
                char buffer[4096];

                if (gethostname(buffer, 4096) == 0)
                {
                        /* gethostname doesn't always return the full name... */
                        struct hostent *ent;

                        buffer[4095] = '\0';
                        ent = gethostbyname(buffer);
                        name = g_strdup(ent ? ent->h_name : buffer);
                }
                else
                {
                        g_warning("gethostname() failed - using localhost\n");
                        name = g_strdup("localhost");
                }
        }

        return name;
}

void debug_free_string(void *data)
{
        g_print("Freeing string '%s'\n", (char *) data);
        g_free(data);
}

const char *user_name(uid_t uid)
{
        const char *retval;
        
        if (!uid_hash)
                uid_hash = g_hash_table_new(NULL, NULL);

        retval = g_hash_table_lookup(uid_hash, GINT_TO_POINTER(uid));

        if (!retval)
        {
                struct passwd *passwd;

                passwd = getpwuid(uid);
                retval = passwd ? g_strdup(passwd->pw_name)
                               : g_strdup_printf("[%d]", (int) uid);
                g_hash_table_insert(uid_hash, GINT_TO_POINTER(uid),
                                (gchar *) retval);
        }

        return retval;
}

const char *group_name(gid_t gid)
{
        const char *retval;
        
        if (!gid_hash)
                gid_hash = g_hash_table_new(NULL, NULL);

        retval = g_hash_table_lookup(gid_hash, GINT_TO_POINTER(gid));

        if (!retval)
        {
                struct group *group;

                group = getgrgid(gid);
                retval = group ? g_strdup(group->gr_name)
                               : g_strdup_printf("[%d]", (int) gid);
                g_hash_table_insert(gid_hash, GINT_TO_POINTER(gid),
                                (gchar *) retval);
        }

        return retval;
}

/* Return a string in the form '23 M' in a static buffer valid until
 * the next call.
 */
const char *format_size(off_t size)
{
        static  char *buffer = NULL;
        const char      *units;
        
        if (size >= PRETTY_SIZE_LIMIT)
        {
                size += 1023;
                size >>= 10;
                if (size >= PRETTY_SIZE_LIMIT)
                {
                        size += 1023;
                        size >>= 10;
                        if (size >= PRETTY_SIZE_LIMIT)
                        {
                                size += 1023;
                                size >>= 10;
                                units = "G";
                        }
                        else
                                units = "M";
                }
                else
                        units = "K";
        }
        else
                units = _("B");

        g_free(buffer);
        buffer = g_strdup_printf("%" SIZE_FMT " %s", size, units);

        return buffer;
}

/* Return a string in the form '23M' in a static buffer valid until
 * the next call. Aligned to the right (5 chars).
 */
const char *format_size_aligned(off_t size)
{
        static  char *buffer = NULL;
        char    units;
        
        if (size >= PRETTY_SIZE_LIMIT)
        {
                size += 1023;
                size >>= 10;
                if (size >= PRETTY_SIZE_LIMIT)
                {
                        size += 1023;
                        size >>= 10;
                        if (size >= PRETTY_SIZE_LIMIT)
                        {
                                size += 1023;
                                size >>= 10;
                                units = 'G';
                        }
                        else
                                units = 'M';
                }
                else
                        units = 'K';
        }
        else
                units = ' ';

        g_free(buffer);
        buffer = g_strdup_printf("%4" SIZE_FMT "%c", size, units);
        
        return buffer;
}

/*
 * Similar to format_size(), but this one uses a double argument since
 * unsigned long isn't wide enough on all platforms and we must be able to
 * sum sizes above 4 GB.
 */
const gchar *format_double_size(double size)
{
        static gchar    *buf = NULL;
        const char      *units;

        if (size >= PRETTY_SIZE_LIMIT)
        {
                size += 1023;
                size /= 1024;
                if (size >= PRETTY_SIZE_LIMIT)
                {
                        size += 1023;
                        size /= 1024;
                        if (size >= PRETTY_SIZE_LIMIT)
                        {
                                size += 1023;
                                size /= 1024;
                                units = "G";
                        }
                        else
                                units = "M";
                }
                else
                        units = "K";

        }
        else if (size != 1)
                units = _("bytes");
        else
                units = _("byte");

        g_free(buf);
        buf = g_strdup_printf("%.0f %s", floor(size), units);

        return buf;
}

/* Fork and exec argv. Wait and return the child's exit status.
 * -1 if spawn fails.
 * Returns the error string from the command if any, or NULL on success.
 * If the process returns a non-zero exit status without producing a message,
 * a suitable message is created.
 * g_free() the result.
 */
char *fork_exec_wait(const char **argv)
{
        int     status;
        gchar   *errors = NULL;
        GError  *error = NULL;

        if (!g_spawn_sync(NULL, (char **) argv, NULL,
                     G_SPAWN_SEARCH_PATH | G_SPAWN_STDOUT_TO_DEV_NULL,
                     NULL, NULL,
                     NULL, &errors, &status, &error))
        {
                char *msg;

                msg = g_strdup(error->message);
                g_error_free(error);
                return msg;
        }

        if (errors && !*errors)
                null_g_free(&errors);

        if (!WIFEXITED(status))
        {
                if (!errors)
                        errors = g_strdup("(Subprocess crashed?)");
        }
        else if (WEXITSTATUS(status))
        {
                if (!errors)
                        errors = g_strdup(_("ERROR"));
        }

        if (errors)
                g_strstrip(errors);

        return errors;
}

/* If a file has this UID and GID, which permissions apply to us?
 * 0 = User, 1 = Group, 2 = World
 */
gint applicable(uid_t uid, gid_t gid)
{
        int     i;

        if (uid == euid)
                return 0;

        if (gid == egid)
                return 1;

        for (i = 0; i < ngroups; i++)
        {
                if (supplemental_groups[i] == gid)
                        return 1;
        }

        return 2;
}

/* Converts a file's mode to a string. Result is a pointer
 * to a static buffer, valid until the next call.
 */
const char *pretty_permissions(mode_t m)
{
        static char buffer[] = "rwx,rwx,rwx/UG"
#ifdef S_ISVTX
             "T"
#endif
             ;

        buffer[0]  = m & S_IRUSR ? 'r' : '-';
        buffer[1]  = m & S_IWUSR ? 'w' : '-';
        buffer[2]  = m & S_IXUSR ? 'x' : '-';

        buffer[4]  = m & S_IRGRP ? 'r' : '-';
        buffer[5]  = m & S_IWGRP ? 'w' : '-';
        buffer[6]  = m & S_IXGRP ? 'x' : '-';

        buffer[8]  = m & S_IROTH ? 'r' : '-';
        buffer[9]  = m & S_IWOTH ? 'w' : '-';
        buffer[10] = m & S_IXOTH ? 'x' : '-';

        buffer[12] = m & S_ISUID ? 'U' : '-';
        buffer[13] = m & S_ISGID ? 'G' : '-';
#ifdef S_ISVTX
        buffer[14] = m & S_ISVTX ? 'T' : '-';
#endif

        return buffer;
}

/* Gets the canonical name for address and compares to our_host_name() */
static gboolean is_local_address(char *address)
{
        struct hostent *ent;

        ent = gethostbyname(address);

        return strcmp(our_host_name(), ent ? ent->h_name : address) == 0;
}

/* Convert a URI to a local pathname (or NULL if it isn't local).
 * The returned pointer points inside the input string.
 * Possible formats:
 *      /path
 *      ///path
 *      //host/path
 *      file://host/path
 */
const char *get_local_path(const char *uri)
{
        if (*uri == '/')
        {
                char    *path, *uri_host;

                if (uri[1] != '/')
                        return uri;     /* Just a local path - no host part */

                path = strchr(uri + 2, '/');
                if (!path)
                        return NULL;        /* //something */

                if (path - uri == 2)
                        return path;    /* ///path */
                
                uri_host = g_strndup(uri + 2, path - uri - 2);
                if (is_local_address(uri_host))
                {
                        g_free(uri_host);
                        return path;    /* //myhost/path */
                }
                g_free(uri_host);

                return NULL;        /* From a different host */
        }
        else
        {
                if (strncasecmp(uri, "file:", 5))
                        return NULL;        /* Don't know this format */

                uri += 5;

                if (*uri == '/')
                        return get_local_path(uri);

                return NULL;
        }
}

/* Set the close-on-exec flag for this FD.
 * TRUE means that an exec()'d process will not get the FD.
 */
void close_on_exec(int fd, gboolean close)
{
        if (fcntl(fd, F_SETFD, close))
                g_warning("fcntl() failed: %s\n", g_strerror(errno));
}

void set_blocking(int fd, gboolean blocking)
{
        if (fcntl(fd, F_SETFL, blocking ? 0 : O_NONBLOCK))
                g_warning("fcntl() failed: %s\n", g_strerror(errno));
}

/* Format this time nicely.
 * g_free() the result.
 */
char *pretty_time(const time_t *time)
{
        char time_buf[32];

        if (strftime(time_buf, sizeof(time_buf),
                        TIME_FORMAT, localtime(time)) == 0)
                time_buf[0]= 0;

        return to_utf8(time_buf);
}

#ifndef O_NOFOLLOW
#  define O_NOFOLLOW 0x0
#endif

/* 'from' and 'to' are complete pathnames of files (not dirs or symlinks).
 * This spawns 'cp' to do the copy if lstat() succeeds, otherwise we
 * do the copy manually using vfs.
 *
 * Returns an error string, or NULL on success. g_free() the result.
 *
 * XXX: This was only used for libvfs...
 */
guchar *copy_file(const guchar *from, const guchar *to)
{
        const char *argv[] = {"cp", "-pRf", NULL, NULL, NULL};

        argv[2] = from;
        argv[3] = to;

        return fork_exec_wait(argv);
}

/* 'word' has all special characters escaped so that it may be inserted
 * into a shell command.
 * Eg: 'My Dir?' becomes 'My\ Dir\?'. g_free() the result.
 */
guchar *shell_escape(const guchar *word)
{
        GString *tmp;
        guchar  *retval;

        tmp = g_string_new(NULL);

        while (*word)
        {
                if (strchr(" ?*['\"$~\\|();!`&", *word))
                        g_string_append_c(tmp, '\\');
                g_string_append_c(tmp, *word);
                word++;
        }

        retval = tmp->str;
        g_string_free(tmp, FALSE);
        return retval;
}

/* TRUE iff `sub' is (or would be) an object inside the directory `parent',
 * (or the two are the same item/directory).
 * FALSE if parent doesn't exist.
 */
gboolean is_sub_dir(const char *sub_obj, const char *parent)
{
        struct stat parent_info;
        char *sub;

        if (mc_lstat(parent, &parent_info))
                return FALSE;           /* Parent doesn't exist */

        /* For checking Copy/Move operations do a realpath first on sub
         * (the destination), since copying into a symlink is the same as
         * copying into the thing it points to. Don't realpath 'parent' though;
         * copying a symlink just makes a new symlink.
         * 
         * When checking if an icon depends on a file (parent), use realpath on
         * sub (the icon) too.
         */
        sub = pathdup(sub_obj);
        
        while (1)
        {
                char        *slash;
                struct stat info;
                
                if (mc_lstat(sub, &info) == 0)
                {
                        if (info.st_dev == parent_info.st_dev &&
                                info.st_ino == parent_info.st_ino)
                        {
                                g_free(sub);
                                return TRUE;
                        }
                }
                
                slash = strrchr(sub, '/');
                if (!slash)
                        break;
                if (slash == sub)
                {
                        if (sub[1])
                                sub[1] = '\0';
                        else
                                break;
                }
                else
                        *slash = '\0';
        }

        g_free(sub);

        return FALSE;
}

/* True if the string 'list' contains 'item'.
 * Eg ("close", "close, help") -> TRUE
 */
gboolean in_list(const guchar *item, const guchar *list)
{
        int     len;

        len = strlen(item);
        
        while (*list)
        {
                if (strncmp(item, list, len) == 0 && !isalpha(list[len]))
                        return TRUE;
                list = strchr(list, ',');
                if (!list)
                        return FALSE;
                while (isspace(*++list))
                        ;
        }

        return FALSE;
}

/* Split a path into its components. Eg:
 *
 * /bob/fred -> ["bob", "fred"]
 * ///a//b// -> ["a", "b"]
 * /         -> []
 *
 * The array and the strings in it must be freed after use.
 */
GPtrArray *split_path(const guchar *path)
{
        GPtrArray *array;
        guchar  *slash;

        g_return_val_if_fail(path != NULL, NULL);

        array = g_ptr_array_new();

        while (1)
        {
                while (path[0] == '/')
                        path++;
                if (path[0] == '\0')
                        break;
                
                slash = strchr(path, '/');
                if (slash)
                {
                        g_ptr_array_add(array, g_strndup(path, slash - path));
                        path = slash + 1;
                        continue;
                }
                g_ptr_array_add(array, g_strdup(path));
                break;
        }

        return array;
}

/* Return the shortest path from 'from' to 'to'.
 * Eg: get_relative_path("/a/b/c", "a/d/e") -> "../d/e"
 */
guchar *get_relative_path(const guchar *from, const guchar *to)
{
        GString  *path;
        guchar   *retval;
        GPtrArray *src, *dst;
        int     i, j;

        src = split_path(from);
        dst = split_path(to);

        /* The last component of src doesn't matter... */
        if (src->len)
        {
                g_free(src->pdata[src->len - 1]);
                g_ptr_array_remove_index(src, src->len - 1);
        }

        /* Strip off common path elements... */
        i = 0;
        while (i < src->len && i < dst->len)
        {
                guchar  *a = (guchar *) src->pdata[i];
                guchar  *b = (guchar *) dst->pdata[i];

                if (strcmp(a, b) != 0)
                        break;
                i++;
        }

        /* Go up one dir for each element remaining in src */
        path = g_string_new(NULL);
        for (j = i; j < src->len; j++)
                g_string_append(path, "../");

        /* Go down one dir for each element remaining in dst */
        for (j = i; j < dst->len; j++)
        {
                g_string_append(path, (guchar *) dst->pdata[j]);
                g_string_append_c(path, '/');
        }

        if (path->str[path->len - 1] == '/')
                g_string_truncate(path, path->len - 1);
        if (path->len == 0)
                g_string_assign(path, ".");

        /* Free the arrays */
        for (i = 0; i < src->len; i++)
                g_free(src->pdata[i]);
        g_ptr_array_free(src, TRUE);
        for (i = 0; i < dst->len; i++)
                g_free(dst->pdata[i]);
        g_ptr_array_free(dst, TRUE);

        retval = path->str;
        g_string_free(path, FALSE);

        return retval;
}

/*
 * Interperet text as a boolean value.  Return defvalue if we don't
 * recognise it
 */
int text_to_boolean(const char *text, int defvalue)
{
        if (g_strcasecmp(text, "true")==0)
                return TRUE;
        else if (g_strcasecmp(text, "false")==0)
                return FALSE;
        else if (g_strcasecmp(text, "yes")==0)
                return TRUE;
        else if (g_strcasecmp(text, "no")==0)
                return FALSE;
        else if (isdigit(text[0]))
                return !!atoi(text);

        return defvalue;
}

/* Return the pathname that this symlink points to.
 * NULL on error (not a symlink, path too long) and errno set.
 * g_free() the result.
 */
char *readlink_dup(const char *source)
{
        char    path[MAXPATHLEN + 1];
        int     got;

        got = readlink(source, path, MAXPATHLEN);
        if (got < 0 || got > MAXPATHLEN)
                return NULL;

        return g_strndup(path, got);
}

/*
 * This code implements the MD5 message-digest algorithm.
 * The algorithm is due to Ron Rivest. The original code was
 * written by Colin Plumb in 1993, and put in the public domain.
 * 
 * Modified to use glib datatypes. Put under GPL to simplify
 * licensing for ROX-Filer. Taken from Debian's dpkg package.
 */

#define md5byte unsigned char

typedef struct _MD5Context MD5Context;

struct _MD5Context {
        guint32 buf[4];
        guint32 bytes[2];
        guint32 in[16];
};

#if G_BYTE_ORDER == G_BIG_ENDIAN
void byteSwap(guint32 *buf, unsigned words)
{
        md5byte *p = (md5byte *)buf;

        do {
                *buf++ = (guint32)((unsigned)p[3] << 8 | p[2]) << 16 |
                        ((unsigned)p[1] << 8 | p[0]);
                p += 4;
        } while (--words);
}
#else
#define byteSwap(buf,words)
#endif

/*
 * Start MD5 accumulation. Set bit count to 0 and buffer to mysterious
 * initialization constants.
 */
static void MD5Init(MD5Context *ctx)
{
        ctx->buf[0] = 0x67452301;
        ctx->buf[1] = 0xefcdab89;
        ctx->buf[2] = 0x98badcfe;
        ctx->buf[3] = 0x10325476;

        ctx->bytes[0] = 0;
        ctx->bytes[1] = 0;
}

/*
 * Update context to reflect the concatenation of another buffer full
 * of bytes.
 */
static void MD5Update(MD5Context *ctx, md5byte const *buf, unsigned len)
{
        guint32 t;

        /* Update byte count */

        t = ctx->bytes[0];
        if ((ctx->bytes[0] = t + len) < t)
                ctx->bytes[1]++;        /* Carry from low to high */

        t = 64 - (t & 0x3f);    /* Space available in ctx->in (at least 1) */
        if (t > len) {
                memcpy((md5byte *)ctx->in + 64 - t, buf, len);
                return;
        }
        /* First chunk is an odd size */
        memcpy((md5byte *)ctx->in + 64 - t, buf, t);
        byteSwap(ctx->in, 16);
        MD5Transform(ctx->buf, ctx->in);
        buf += t;
        len -= t;

        /* Process data in 64-byte chunks */
        while (len >= 64) {
                memcpy(ctx->in, buf, 64);
                byteSwap(ctx->in, 16);
                MD5Transform(ctx->buf, ctx->in);
                buf += 64;
                len -= 64;
        }

        /* Handle any remaining bytes of data. */
        memcpy(ctx->in, buf, len);
}

/*
 * Final wrapup - pad to 64-byte boundary with the bit pattern 
 * 1 0* (64-bit count of bits processed, MSB-first)
 * Returns the newly allocated string of the hash.
 */
static char *MD5Final(MD5Context *ctx)
{
        char *retval;
        int i;
        int count = ctx->bytes[0] & 0x3f;       /* Number of bytes in ctx->in */
        md5byte *p = (md5byte *)ctx->in + count;
        guint8  *bytes;

        /* Set the first char of padding to 0x80.  There is always room. */
        *p++ = 0x80;

        /* Bytes of padding needed to make 56 bytes (-8..55) */
        count = 56 - 1 - count;

        if (count < 0) {        /* Padding forces an extra block */
                memset(p, 0, count + 8);
                byteSwap(ctx->in, 16);
                MD5Transform(ctx->buf, ctx->in);
                p = (md5byte *)ctx->in;
                count = 56;
        }
        memset(p, 0, count);
        byteSwap(ctx->in, 14);

        /* Append length in bits and transform */
        ctx->in[14] = ctx->bytes[0] << 3;
        ctx->in[15] = ctx->bytes[1] << 3 | ctx->bytes[0] >> 29;
        MD5Transform(ctx->buf, ctx->in);

        byteSwap(ctx->buf, 4);

        retval = g_malloc(33);
        bytes = (guint8 *) ctx->buf;
        for (i = 0; i < 16; i++)
                sprintf(retval + (i * 2), "%02x", bytes[i]);
        retval[32] = '\0';
        
        return retval;
}

# ifndef ASM_MD5

/* The four core functions - F1 is optimized somewhat */

/* #define F1(x, y, z) (x & y | ~x & z) */
#define F1(x, y, z) (z ^ (x & (y ^ z)))
#define F2(x, y, z) F1(z, x, y)
#define F3(x, y, z) (x ^ y ^ z)
#define F4(x, y, z) (y ^ (x | ~z))

/* This is the central step in the MD5 algorithm. */
#define MD5STEP(f,w,x,y,z,in,s) \
         (w += f(x,y,z) + in, w = (w<<s | w>>(32-s)) + x)

/*
 * The core of the MD5 algorithm, this alters an existing MD5 hash to
 * reflect the addition of 16 longwords of new data.  MD5Update blocks
 * the data and converts bytes into longwords for this routine.
 */
static void MD5Transform(guint32 buf[4], guint32 const in[16])
{
        register guint32 a, b, c, d;

        a = buf[0];
        b = buf[1];
        c = buf[2];
        d = buf[3];

        MD5STEP(F1, a, b, c, d, in[0] + 0xd76aa478, 7);
        MD5STEP(F1, d, a, b, c, in[1] + 0xe8c7b756, 12);
        MD5STEP(F1, c, d, a, b, in[2] + 0x242070db, 17);
        MD5STEP(F1, b, c, d, a, in[3] + 0xc1bdceee, 22);
        MD5STEP(F1, a, b, c, d, in[4] + 0xf57c0faf, 7);
        MD5STEP(F1, d, a, b, c, in[5] + 0x4787c62a, 12);
        MD5STEP(F1, c, d, a, b, in[6] + 0xa8304613, 17);
        MD5STEP(F1, b, c, d, a, in[7] + 0xfd469501, 22);
        MD5STEP(F1, a, b, c, d, in[8] + 0x698098d8, 7);
        MD5STEP(F1, d, a, b, c, in[9] + 0x8b44f7af, 12);
        MD5STEP(F1, c, d, a, b, in[10] + 0xffff5bb1, 17);
        MD5STEP(F1, b, c, d, a, in[11] + 0x895cd7be, 22);
        MD5STEP(F1, a, b, c, d, in[12] + 0x6b901122, 7);
        MD5STEP(F1, d, a, b, c, in[13] + 0xfd987193, 12);
        MD5STEP(F1, c, d, a, b, in[14] + 0xa679438e, 17);
        MD5STEP(F1, b, c, d, a, in[15] + 0x49b40821, 22);

        MD5STEP(F2, a, b, c, d, in[1] + 0xf61e2562, 5);
        MD5STEP(F2, d, a, b, c, in[6] + 0xc040b340, 9);
        MD5STEP(F2, c, d, a, b, in[11] + 0x265e5a51, 14);
        MD5STEP(F2, b, c, d, a, in[0] + 0xe9b6c7aa, 20);
        MD5STEP(F2, a, b, c, d, in[5] + 0xd62f105d, 5);
        MD5STEP(F2, d, a, b, c, in[10] + 0x02441453, 9);
        MD5STEP(F2, c, d, a, b, in[15] + 0xd8a1e681, 14);
        MD5STEP(F2, b, c, d, a, in[4] + 0xe7d3fbc8, 20);
        MD5STEP(F2, a, b, c, d, in[9] + 0x21e1cde6, 5);
        MD5STEP(F2, d, a, b, c, in[14] + 0xc33707d6, 9);
        MD5STEP(F2, c, d, a, b, in[3] + 0xf4d50d87, 14);
        MD5STEP(F2, b, c, d, a, in[8] + 0x455a14ed, 20);
        MD5STEP(F2, a, b, c, d, in[13] + 0xa9e3e905, 5);
        MD5STEP(F2, d, a, b, c, in[2] + 0xfcefa3f8, 9);
        MD5STEP(F2, c, d, a, b, in[7] + 0x676f02d9, 14);
        MD5STEP(F2, b, c, d, a, in[12] + 0x8d2a4c8a, 20);

        MD5STEP(F3, a, b, c, d, in[5] + 0xfffa3942, 4);
        MD5STEP(F3, d, a, b, c, in[8] + 0x8771f681, 11);
        MD5STEP(F3, c, d, a, b, in[11] + 0x6d9d6122, 16);
        MD5STEP(F3, b, c, d, a, in[14] + 0xfde5380c, 23);
        MD5STEP(F3, a, b, c, d, in[1] + 0xa4beea44, 4);
        MD5STEP(F3, d, a, b, c, in[4] + 0x4bdecfa9, 11);
        MD5STEP(F3, c, d, a, b, in[7] + 0xf6bb4b60, 16);
        MD5STEP(F3, b, c, d, a, in[10] + 0xbebfbc70, 23);
        MD5STEP(F3, a, b, c, d, in[13] + 0x289b7ec6, 4);
        MD5STEP(F3, d, a, b, c, in[0] + 0xeaa127fa, 11);
        MD5STEP(F3, c, d, a, b, in[3] + 0xd4ef3085, 16);
        MD5STEP(F3, b, c, d, a, in[6] + 0x04881d05, 23);
        MD5STEP(F3, a, b, c, d, in[9] + 0xd9d4d039, 4);
        MD5STEP(F3, d, a, b, c, in[12] + 0xe6db99e5, 11);
        MD5STEP(F3, c, d, a, b, in[15] + 0x1fa27cf8, 16);
        MD5STEP(F3, b, c, d, a, in[2] + 0xc4ac5665, 23);

        MD5STEP(F4, a, b, c, d, in[0] + 0xf4292244, 6);
        MD5STEP(F4, d, a, b, c, in[7] + 0x432aff97, 10);
        MD5STEP(F4, c, d, a, b, in[14] + 0xab9423a7, 15);
        MD5STEP(F4, b, c, d, a, in[5] + 0xfc93a039, 21);
        MD5STEP(F4, a, b, c, d, in[12] + 0x655b59c3, 6);
        MD5STEP(F4, d, a, b, c, in[3] + 0x8f0ccc92, 10);
        MD5STEP(F4, c, d, a, b, in[10] + 0xffeff47d, 15);
        MD5STEP(F4, b, c, d, a, in[1] + 0x85845dd1, 21);
        MD5STEP(F4, a, b, c, d, in[8] + 0x6fa87e4f, 6);
        MD5STEP(F4, d, a, b, c, in[15] + 0xfe2ce6e0, 10);
        MD5STEP(F4, c, d, a, b, in[6] + 0xa3014314, 15);
        MD5STEP(F4, b, c, d, a, in[13] + 0x4e0811a1, 21);
        MD5STEP(F4, a, b, c, d, in[4] + 0xf7537e82, 6);
        MD5STEP(F4, d, a, b, c, in[11] + 0xbd3af235, 10);
        MD5STEP(F4, c, d, a, b, in[2] + 0x2ad7d2bb, 15);
        MD5STEP(F4, b, c, d, a, in[9] + 0xeb86d391, 21);

        buf[0] += a;
        buf[1] += b;
        buf[2] += c;
        buf[3] += d;
}

# endif /* ASM_MD5 */

char *md5_hash(const char *message)
{
        MD5Context ctx;

        MD5Init(&ctx);
        MD5Update(&ctx, message, strlen(message));
        return MD5Final(&ctx);
}

/* Convert string 'src' from the current locale to UTF-8 */
gchar *to_utf8(const gchar *src)
{
        gchar *retval;

        if (!src)
                return NULL;

        retval = g_locale_to_utf8(src, -1, NULL, NULL, NULL);
        if (!retval)
                retval = g_convert_with_fallback(src, -1, "utf-8", "iso-8859-1",
                                                "?", NULL, NULL, NULL);

        return retval ? retval : g_strdup(src);
}

/* Ensure string at 'sp' is UTF-8. g_free() and replace by
 * UTF-8 version if not.
 */
void ensure_utf8(gchar **sp)
{
        gchar *s = *sp;

        if (!g_utf8_validate(s, -1, NULL))
        {
                *sp = to_utf8(s);
                g_free(s);
        }
}

/* Removes trailing / chars and converts a leading '~/' (if any) to
 * the user's home dir. g_free() the result.
 */
gchar *expand_path(const gchar *path)
{
        guchar          *retval;
        int             path_len;

        g_return_val_if_fail(path != NULL, NULL);

        path_len = strlen(path);
        while (path_len > 1 && path[path_len - 1] == '/')
                path_len--;
        
        retval = g_strndup(path, path_len);

        if (path[0] == '~' && (path[1] == '\0' || path[1] == '/'))
        {
                guchar *tmp = retval;

                retval = g_strconcat(home_dir, retval + 1, NULL);
                g_free(tmp);
        }

        return retval;
}

/* g_free() every element in the list, then free the list itself and
 * NULL the pointer to the list.
 */
void destroy_glist(GList **list)
{
        GList *l = *list;
        g_list_foreach(l, (GFunc) g_free, NULL);
        g_list_free(l);
        *list = NULL;
}

void null_g_free(gpointer p)
{
        g_free(*(gpointer *)p);
        *(gpointer *)p = NULL;
}

typedef struct _CollatePart CollatePart;

struct _CollateKey {
        CollatePart *parts;
        gboolean caps;
};

struct _CollatePart {
        guchar *text;   /* NULL => end of list */
        long number;
};

/* Break 'name' (a UTF-8 string) down into a list of (text, number) pairs.
 * The text parts processed for collating. This allows any two names to be
 * quickly compared later for intelligent sorting (comparing names is
 * speed-critical).
 */
CollateKey *collate_key_new(const guchar *name)
{
        const guchar *i;
        guchar *to_free = NULL;
        GArray *array;
        CollatePart new;
        CollateKey *retval;
        char *tmp;

        g_return_val_if_fail(name != NULL, NULL);

        array = g_array_new(FALSE, FALSE, sizeof(CollatePart));

        /* Ensure valid UTF-8 */
        if (!g_utf8_validate(name, -1, NULL))
        {
                to_free = to_utf8(name);
                name = to_free;
        }

        retval = g_new(CollateKey, 1);
        retval->caps = g_unichar_isupper(g_utf8_get_char(name));

        for (i = name; *i; i = g_utf8_next_char(i))
        {
                /* We're in a (possibly blank) text section starting at 'name'.
                 * Find the end of it (the next digit, or end of string).
                 */
                if (g_unichar_isdigit(g_utf8_get_char(i)))
                {
                        char *endp;
                        
                        /* i -> first digit character */
                        tmp = g_utf8_strdown(name, i - name);
                        new.text = g_utf8_collate_key(tmp, -1);
                        g_free(tmp);
                        new.number = strtol(i, &endp, 10);

                        g_array_append_val(array, new);

                        g_return_val_if_fail(endp > (char *) i, NULL);

                        name = endp;
                        i = name - 1;
                }
        }

        tmp = g_utf8_strdown(name, i - name);
        new.text = g_utf8_collate_key(tmp, -1);
        g_free(tmp);
        new.number = -1;
        g_array_append_val(array, new);

        new.text = NULL;
        g_array_append_val(array, new);

        retval->parts = (CollatePart *) array->data;
        g_array_free(array, FALSE);

        if (to_free)
                g_free(to_free);        /* Only taken for invalid UTF-8 */

        return retval;
}

void collate_key_free(CollateKey *key)
{
        CollatePart *part;

        for (part = key->parts; part->text; part++)
                g_free(part->text);
        g_free(key->parts);
        g_free(key);
}

int collate_key_cmp(const CollateKey *key1, const CollateKey *key2,
                    gboolean caps_first)
{
        CollatePart *n1 = key1->parts;
        CollatePart *n2 = key2->parts;
        int r;

        if (caps_first)
        {
                if (key1->caps && !key2->caps)
                        return -1;
                else if (key2->caps && !key1->caps)
                        return 1;
        }

        while (1)
        {
                if (!n1->text)
                        return n2->text ? -1 : 0;
                if (!n2->text)
                        return 1;
                r = strcmp(n1->text, n2->text);
                if (r)
                        return r;

                if (n1->number < n2->number)
                        return -1;
                if (n1->number > n2->number)
                        return 1;

                n1++;
                n2++;
        }
}

/* Returns TRUE if the object exists, FALSE if it doesn't.
 * For symlinks, the file pointed to must exist.
 */
gboolean file_exists(const char *path)
{
        struct stat info;

        return !mc_stat(path, &info);
}

/* Code for escaping and unescaping URI's for DnD */
gchar *escape_uri(const char *uri)
{
        const char *p;
        const char *spath=NULL;
        gchar *tmp, *t2, *enc;

        /* skip the scheme */
        p=uri;
        do {
                p++;
                if(*p==':' || *p=='/')
                        break;
        } while(*p);

 
        if(*p==':') 
                p++;
        /* What is next is either
          //host/path
          ///path
          /path
          not-a-path
        */
        if(p[0]=='/' && p[1]=='/') {
                p+=2;
                while(*p!='/')
                        p++;
                if(*p)
                        spath=p;
        } else if(p[0]) {
                spath=p;
        }

        if(!spath)
                return g_strdup(uri);

        tmp=escape_uri_path(spath);
        t2=g_strndup(uri, spath-uri);
        /*printf("%s %s (%s)\n", t2, tmp, spath);*/
        enc=g_strconcat(t2, tmp, NULL);
        g_free(tmp);
        g_free(t2);

        return enc;
}

/* Escape path for future use in URI */
gchar *escape_uri_path(const char *path)
{
        const char *safe = "-_./"; /* Plus isalnum() */
        const guchar *s;
        gchar *ans;
        GString *str;

        str = g_string_sized_new(strlen(path));

        for (s = path; *s; s++)
        {
                if (!g_ascii_isalnum(*s) && !strchr(safe, *s))
                        g_string_append_printf(str, "%%%02x", *s);
                else
                        str = g_string_append_c(str, *s);
        }

        ans = str->str;
        g_string_free(str, FALSE);
        
        return ans;
}

gchar *encode_path_as_uri(const guchar *path)
{
        gchar *tpath = escape_uri_path(path);
        gchar *uri;

        uri = g_strconcat("file://", our_host_name_for_dnd(), tpath, NULL);
        g_free(tpath);

        return uri;
}

gchar *unescape_uri(const char *uri)
{
        const gchar *s;
        gchar *d;
        gchar *tmp;
        
        tmp = g_strdup(uri);
        for (s = uri, d=tmp; *s; s++, d++)
        {
                /*printf("%s\n", s);*/
                if (*s=='%' && g_ascii_isxdigit(s[1]) &&
                   g_ascii_isxdigit(s[2])) {
                        int c;
                        char buf[3];
                        buf[0]=s[1];
                        buf[1]=s[2];
                        buf[2]=0;
                        c=(int) strtol(buf, NULL, 16);
                        *d=c;
                        s+=2;
                } else {
                        *d=*s;
                }
        }
        *d=0;

        return tmp;
}