path: root/camel/providers/nntp/camel-nntp-store.c

/* -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*- */
/* camel-nntp-store.c : class for an nntp store */

/* 
 *
 * Copyright (C) 2000 Helix Code, Inc. <toshok@helixcode.com>
 *
 * 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
 */

#include <config.h>

#include <dirent.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include "libgnome/libgnome.h"

#include "camel-nntp-resp-codes.h"
#include "camel-folder-summary.h"
#include "camel-nntp-store.h"
#include "camel-nntp-grouplist.h"
#include "camel-nntp-folder.h"
#include "camel-nntp-auth.h"
#include "camel-exception.h"
#include "camel-url.h"
#include "string-utils.h"

#define NNTP_PORT 119

#define DUMP_EXTENSIONS

/* define if you want the subscribe ui to show folders in tree form */
/* #define INFO_AS_TREE */

static CamelRemoteStoreClass *remote_store_class = NULL;

static CamelServiceClass *service_class = NULL;

/* Returns the class for a CamelNNTPStore */
#define CNNTPS_CLASS(so) CAMEL_NNTP_STORE_CLASS (CAMEL_OBJECT_GET_CLASS(so))
#define CF_CLASS(so) CAMEL_FOLDER_CLASS (CAMEL_OBJECT_GET_CLASS(so))
#define CNNTPF_CLASS(so) CAMEL_NNTP_FOLDER_CLASS (CAMEL_OBJECT_GET_CLASS(so))

static gboolean ensure_news_dir_exists (CamelNNTPStore *store);

static void
camel_nntp_store_get_extensions (CamelNNTPStore *store, CamelException *ex)
{
    store->extensions = 0;

    if (camel_nntp_command (store, ex, NULL, "LIST EXTENSIONS") == NNTP_LIST_FOLLOWS) {
        gboolean done = FALSE;
        CamelException ex;

        camel_exception_init (&ex);

        while (!done) {
            char *line;

            if (camel_remote_store_recv_line (CAMEL_REMOTE_STORE (store), &line, &ex) < 0)
                break; /* XXX */

            if (*line == '.') {
                done = TRUE;
            }
            else {
#define CHECK_EXT(name,val) if (!strcasecmp (line, (name))) store->extensions |= (val)

                CHECK_EXT ("SEARCH",     CAMEL_NNTP_EXT_SEARCH);
                CHECK_EXT ("SETGET",     CAMEL_NNTP_EXT_SETGET);
                CHECK_EXT ("OVER",       CAMEL_NNTP_EXT_OVER);
                CHECK_EXT ("XPATTEXT",   CAMEL_NNTP_EXT_XPATTEXT);
                CHECK_EXT ("XACTIVE",    CAMEL_NNTP_EXT_XACTIVE);
                CHECK_EXT ("LISTMOTD",   CAMEL_NNTP_EXT_LISTMOTD);
                CHECK_EXT ("LISTSUBSCR", CAMEL_NNTP_EXT_LISTSUBSCR);
                CHECK_EXT ("LISTPNAMES", CAMEL_NNTP_EXT_LISTPNAMES);

#undef CHECK_EXT
            }

            g_free (line);
        }
    }

#ifdef DUMP_EXTENSIONS
    g_print ("NNTP Extensions:");
#define DUMP_EXT(name,val) if (store->extensions & (val)) g_print (" %s", name);
    DUMP_EXT ("SEARCH",     CAMEL_NNTP_EXT_SEARCH);
    DUMP_EXT ("SETGET",     CAMEL_NNTP_EXT_SETGET);
    DUMP_EXT ("OVER",       CAMEL_NNTP_EXT_OVER);
    DUMP_EXT ("XPATTEXT",   CAMEL_NNTP_EXT_XPATTEXT);
    DUMP_EXT ("XACTIVE",    CAMEL_NNTP_EXT_XACTIVE);
    DUMP_EXT ("LISTMOTD",   CAMEL_NNTP_EXT_LISTMOTD);
    DUMP_EXT ("LISTSUBSCR", CAMEL_NNTP_EXT_LISTSUBSCR);
    DUMP_EXT ("LISTPNAMES", CAMEL_NNTP_EXT_LISTPNAMES);
    g_print ("\n");
#undef DUMP_EXT
#endif
}

static void
camel_nntp_store_get_overview_fmt (CamelNNTPStore *store, CamelException *ex)
{
    int status;
    int i;
    gboolean done = FALSE;
    
    status = camel_nntp_command (store, ex, NULL,
                     "LIST OVERVIEW.FMT");

    if (status != NNTP_LIST_FOLLOWS) {
        if (store->extensions & CAMEL_NNTP_EXT_OVER) {
            /* if we can't get the overview format, we should
               disable OVER support */
            g_warning ("server reported support of OVER but LIST OVERVIEW.FMT failed."
                   "  disabling OVER.\n");
            store->extensions &= ~CAMEL_NNTP_EXT_OVER;
            return;
        }
    }
    else {
        if (!(store->extensions & CAMEL_NNTP_EXT_OVER)) {
            g_warning ("server didn't report support of OVER but LIST OVERVIEW.FMT worked."
                   "  enabling OVER.\n");
            store->extensions |= CAMEL_NNTP_EXT_OVER;
        }
    }

    /* start at 1 because the article number is always first */
    store->num_overview_fields = 1;
    
    for (i = 0; i < CAMEL_NNTP_OVER_LAST; i ++) {
        store->overview_field [i].index = -1;
    }

    while (!done) {
        char *line;

        if (camel_remote_store_recv_line (CAMEL_REMOTE_STORE (store), &line, ex) < 0)
            break; /* XXX */

        if (*line == '.') {
            done = TRUE;
        }
        else {
            CamelNNTPOverField *over_field = NULL;
            char *colon = NULL;;

            if (!strncasecmp (line, "From:", 5)) {
                over_field = &store->overview_field [ CAMEL_NNTP_OVER_FROM ];
                over_field->index = store->num_overview_fields;
                colon = line + 5;
            }
            else if (!strncasecmp (line, "Subject:", 7)) {
                over_field = &store->overview_field [ CAMEL_NNTP_OVER_SUBJECT ];
                over_field->index = store->num_overview_fields;
                colon = line + 7;
            }
            else if (!strncasecmp (line, "Date:", 5)) {
                over_field = &store->overview_field [ CAMEL_NNTP_OVER_DATE ];
                over_field->index = store->num_overview_fields;
                colon = line + 5;
            }
            else if (!strncasecmp (line, "Message-ID:", 11)) {
                over_field = &store->overview_field [ CAMEL_NNTP_OVER_MESSAGE_ID ];
                over_field->index = store->num_overview_fields;
                colon = line + 11;
            }
            else if (!strncasecmp (line, "References:", 11)) {
                over_field = &store->overview_field [ CAMEL_NNTP_OVER_REFERENCES ];
                over_field->index = store->num_overview_fields;
                colon = line + 11;
            }
            else if (!strncasecmp (line, "Bytes:", 6)) {
                over_field = &store->overview_field [ CAMEL_NNTP_OVER_BYTES ];
                over_field->index = store->num_overview_fields;
                colon = line + 11;
            }
        
            if (colon && !strncmp (colon + 1, "full", 4))
                over_field->full = TRUE;

            store->num_overview_fields ++;
        }

        g_free (line);
    }

    for (i = 0; i < CAMEL_NNTP_OVER_LAST; i ++) {
        if (store->overview_field [i].index == -1) {
            g_warning ("server's OVERVIEW.FMT doesn't support minimum set we require,"
                   " disabling OVER support.\n");
            store->extensions &= ~CAMEL_NNTP_EXT_OVER;
        }
    }
}

static gboolean
nntp_store_connect (CamelService *service, CamelException *ex)
{
    char *buf;
    int resp_code;
    CamelNNTPStore *store = CAMEL_NNTP_STORE (service);

    if (!ensure_news_dir_exists(store)) {
        camel_exception_setv (ex, CAMEL_EXCEPTION_SYSTEM,
                      _("Could not open directory for news server: %s"),
                      strerror (errno));
        return FALSE;
    }

    if (CAMEL_SERVICE_CLASS (remote_store_class)->connect (service, ex) == FALSE)
        return FALSE;

    /* Read the greeting */
    if (camel_remote_store_recv_line (CAMEL_REMOTE_STORE (service), &buf, ex) < 0) {
        return FALSE;
    }

    /* check if posting is allowed. */
    resp_code = atoi (buf);
    if (resp_code == NNTP_GREETING_POSTING_OK) {
        g_print ("posting allowed\n");
        store->posting_allowed = TRUE;
    }
    else if (resp_code == NNTP_GREETING_NO_POSTING) {
        g_print ("no posting allowed\n");
        store->posting_allowed = FALSE;
    }
    else {
        g_warning ("unexpected server greeting code %d, no posting allowed\n", resp_code);
        store->posting_allowed = FALSE;
    }

    g_free (buf);

    /* get a list of extensions that the server supports */
    camel_nntp_store_get_extensions (store, ex);

    /* try to get the overview.fmt */
    camel_nntp_store_get_overview_fmt (store, ex);

    return TRUE;
}

static gboolean
nntp_store_disconnect (CamelService *service, gboolean clean, CamelException *ex)
{
    CamelNNTPStore *store = CAMEL_NNTP_STORE (service);

    if (clean)
        camel_nntp_command (store, ex, NULL, "QUIT");

    if (store->newsrc)
        camel_nntp_newsrc_write (store->newsrc);

    if (!service_class->disconnect (service, clean, ex))
        return FALSE;

    return TRUE;
}

static char *
nntp_store_get_name (CamelService *service, gboolean brief)
{
    if (brief)
        return g_strdup_printf ("%s", service->url->host);
    else
        return g_strdup_printf (_("USENET News via %s"), service->url->host);
    
}

static CamelServiceAuthType password_authtype = {
    N_("Password"),
    
    N_("This option will authenticate with the NNTP server using a "
       "plaintext password."),
    
    "",
    TRUE
};

static GList *
nntp_store_query_auth_types (CamelService *service, gboolean connect, CamelException *ex)
{
    GList *prev;
    
    g_warning ("nntp::query_auth_types: not implemented. Defaulting.");
    prev = CAMEL_SERVICE_CLASS (remote_store_class)->query_auth_types (service, ex);
    return g_list_prepend (prev, &password_authtype);
}

static CamelFolder *
nntp_store_get_folder (CamelStore *store, const gchar *folder_name,
               guint32 flags, CamelException *ex)
{
    CamelNNTPStore *nntp_store = CAMEL_NNTP_STORE (store);

    printf ("get_folder called on folder_name=%s\n", folder_name);

    /* if we haven't already read our .newsrc, read it now */
    if (!nntp_store->newsrc)
        nntp_store->newsrc = 
        camel_nntp_newsrc_read_for_server (CAMEL_SERVICE(store)->url->host);

    if (!nntp_store->newsrc) {
        camel_exception_setv (ex, CAMEL_EXCEPTION_SERVICE_UNAVAILABLE,
                      _("Unable to open or create .newsrc file for %s: %s"),
                      CAMEL_SERVICE(store)->url->host,
                      strerror(errno));
        return NULL;
    }

    return camel_nntp_folder_new (store, folder_name, ex);
}

#ifdef INFO_AS_TREE
static void
build_folder_info (CamelNNTPStore *nntp_store, CamelFolderInfo **root,
           CamelFolderInfo *parent, CamelNNTPGroupListEntry *entry,
           char *prefix, char *suffix,
           GHashTable *name_to_info)
{
    CamelURL *url = CAMEL_SERVICE (nntp_store)->url;
    char *dot;
    if ((dot = strchr (suffix, '.'))) {
        /* it's an internal node, figure out the next node in
                   the chain */
        CamelFolderInfo *node;
        char *node_name, *node_full_name;

        node_name = g_malloc0 (dot - suffix + 1);
        strncpy (node_name, suffix, dot - suffix);
        node_full_name = g_strdup_printf ("%s.%s", prefix, node_name);

        node = g_hash_table_lookup (name_to_info, node_full_name);
        if (!node) {
            /* we need to add one */
            node = g_new0 (CamelFolderInfo, 1);
            node->name = g_strdup (node_name);
            node->full_name = g_strdup (node_full_name);
            node->url = NULL;
            node->unread_message_count = -1;

            if (parent) {
                if (parent->child) {
                    node->sibling = parent->child;
                    parent->child = node;
                }
                else {
                    parent->child = node;
                }
            }
            else {
                if (*root) {
                    *root = node;
                }
                else {
                    node->sibling = *root;
                    *root = node;
                }
            }

            g_hash_table_insert (name_to_info, node_full_name, node);
        }

        build_folder_info (nntp_store, root, node, entry, node_full_name, dot + 1, name_to_info);
    }
    else {
        /* it's a leaf node, make the CamelFolderInfo and
                   append it to @parent's list of children. */
        CamelFolderInfo *new_group;

        new_group = g_new0 (CamelFolderInfo, 1);
        new_group->name = g_strdup (entry->group_name);
        new_group->full_name = g_strdup (entry->group_name);
        new_group->url = g_strdup_printf ("nntp://%s%s%s/%s",
                          url->user ? url->user : "",
                          url->user ? "@" : "",
                          url->host, (char *)entry->group_name);

        new_group->unread_message_count = (entry->high - entry->low - 
                           camel_nntp_newsrc_get_num_articles_read (nntp_store->newsrc, entry->group_name));

        if (parent) {
            if (parent->child) {
                new_group->sibling = parent->child;
                parent->child = new_group;
            }
            else {
                parent->child = new_group;
            }
        }
        else {
            if (*root) {
                *root = new_group;
            }
            else {
                new_group->sibling = *root;
                *root = new_group;
            }
        }
    }
}
#endif

static CamelFolderInfo *
build_folder_info_from_grouplist (CamelNNTPStore *nntp_store, const char *top)
{
    GList *g;
    CamelFolderInfo *groups = NULL;
#ifdef INFO_AS_TREE
    GHashTable *hash = g_hash_table_new (g_str_hash, g_str_equal);
#else
    CamelFolderInfo *last = NULL, *fi;
    CamelURL *url = CAMEL_SERVICE (nntp_store)->url;
#endif

    for (g = nntp_store->group_list->group_list; g; g = g_list_next (g)) {
        CamelNNTPGroupListEntry *entry = g->data;

        if (!top || !strncmp (top, entry->group_name, strlen (top))) {
#ifdef INFO_AS_TREE
            build_folder_info (nntp_store, &groups, NULL, entry,
                       "", entry->group_name, hash);
#else

            fi = g_new0 (CamelFolderInfo, 1);
            fi->name = g_strdup (entry->group_name);
            fi->full_name = g_strdup (entry->group_name);
            fi->url = g_strdup_printf ("nntp://%s%s%s/%s",
                           url->user ? url->user : "",
                           url->user ? "@" : "",
                           url->host, (char *)entry->group_name);

            fi->unread_message_count = (entry->high - entry->low - 
                            camel_nntp_newsrc_get_num_articles_read (
                                 nntp_store->newsrc, entry->group_name));

            if (last)
                last->sibling = fi;
            else
                groups = fi;
            last = fi;
#endif
        }
    }

    return groups;
}

static CamelFolderInfo *
nntp_store_get_folder_info (CamelStore *store, const char *top,
                gboolean fast, gboolean recursive,
                gboolean subscribed_only,
                CamelException *ex)
{
    CamelURL *url = CAMEL_SERVICE (store)->url;
    CamelNNTPStore *nntp_store = (CamelNNTPStore *)store;
    GPtrArray *names;
    CamelFolderInfo *groups = NULL, *last = NULL, *fi;
    int i;

    /* if we haven't already read our .newsrc, read it now */
    if (!nntp_store->newsrc)
        nntp_store->newsrc = 
        camel_nntp_newsrc_read_for_server (CAMEL_SERVICE(store)->url->host);

    if (!nntp_store->newsrc) {
        camel_exception_setv (ex, CAMEL_EXCEPTION_SERVICE_UNAVAILABLE,
                      _("Unable to open or create .newsrc file for %s: %s"),
                      CAMEL_SERVICE(store)->url->host,
                      strerror(errno));
        return NULL;
    }

    if (!subscribed_only) {
        if (!nntp_store->group_list)
            nntp_store->group_list = camel_nntp_grouplist_fetch (nntp_store, ex);
        if (camel_exception_is_set (ex)) {
            return NULL;
        }
        else {
            fi = build_folder_info_from_grouplist (nntp_store, top);
            return fi;
        }
    }

    if (top == NULL) {
        /* return the list of groups */
        names = camel_nntp_newsrc_get_subscribed_group_names (nntp_store->newsrc);
        for (i = 0; i < names->len; i++) {
            fi = g_new0 (CamelFolderInfo, 1);
            fi->name = g_strdup (names->pdata[i]);
            fi->full_name = g_strdup (names->pdata[i]);
            fi->url = g_strdup_printf ("nntp://%s%s%s/%s",
                           url->user ? url->user : "",
                           url->user ? "@" : "",
                           url->host, (char *)names->pdata[i]);
            /* FIXME */
            fi->unread_message_count = -1;

            if (last)
                last->sibling = fi;
            else
                groups = fi;
            last = fi;
        }
        camel_nntp_newsrc_free_group_names (nntp_store->newsrc, names);

        return groups;
    }
    else {
        /* getting a specific group */

        fi = g_new0 (CamelFolderInfo, 1);
        fi->name = g_strdup (top);
        fi->full_name = g_strdup (top);
        fi->url = g_strdup_printf ("nntp://%s/%s", url->host, top);
        /* FIXME */
        fi->unread_message_count = -1;

        return fi;
    }
}

static gboolean
nntp_store_folder_subscribed (CamelStore *store, const char *folder_name)
{
    CamelNNTPStore *nntp_store = CAMEL_NNTP_STORE (store);

    return camel_nntp_newsrc_group_is_subscribed (nntp_store->newsrc, folder_name);
}

static void
nntp_store_subscribe_folder (CamelStore *store, const char *folder_name,
                 CamelException *ex)
{
    CamelNNTPStore *nntp_store = CAMEL_NNTP_STORE (store);

    camel_nntp_newsrc_subscribe_group (nntp_store->newsrc, folder_name);
}

static void
nntp_store_unsubscribe_folder (CamelStore *store, const char *folder_name,
                   CamelException *ex)
{
    CamelNNTPStore *nntp_store = CAMEL_NNTP_STORE (store);

    camel_nntp_newsrc_unsubscribe_group (nntp_store->newsrc, folder_name);
}

static void
finalize (CamelObject *object)
{
    CamelNNTPStore *nntp_store = CAMEL_NNTP_STORE (object);
    if (nntp_store->newsrc)
        camel_nntp_newsrc_write (nntp_store->newsrc);
}

static void
camel_nntp_store_class_init (CamelNNTPStoreClass *camel_nntp_store_class)
{
    CamelStoreClass *camel_store_class = CAMEL_STORE_CLASS (camel_nntp_store_class);
    CamelServiceClass *camel_service_class = CAMEL_SERVICE_CLASS (camel_nntp_store_class);

    remote_store_class = CAMEL_REMOTE_STORE_CLASS(camel_type_get_global_classfuncs 
                              (camel_remote_store_get_type ()));

    service_class = CAMEL_SERVICE_CLASS (camel_type_get_global_classfuncs (camel_service_get_type ()));
    
    /* virtual method overload */
    camel_service_class->connect = nntp_store_connect;
    camel_service_class->disconnect = nntp_store_disconnect;
    camel_service_class->query_auth_types = nntp_store_query_auth_types;
    camel_service_class->get_name = nntp_store_get_name;

    camel_store_class->get_folder = nntp_store_get_folder;
    camel_store_class->get_folder_info = nntp_store_get_folder_info;
    camel_store_class->free_folder_info = camel_store_free_folder_info_full;

    camel_store_class->folder_subscribed = nntp_store_folder_subscribed;
    camel_store_class->subscribe_folder = nntp_store_subscribe_folder;
    camel_store_class->unsubscribe_folder = nntp_store_unsubscribe_folder;
}



static void
camel_nntp_store_init (gpointer object, gpointer klass)
{
    CamelRemoteStore *remote_store = CAMEL_REMOTE_STORE (object);
    CamelStore *store = CAMEL_STORE (object);

    remote_store->default_port = NNTP_PORT;

    store->flags = CAMEL_STORE_SUBSCRIPTIONS;
}

CamelType
camel_nntp_store_get_type (void)
{
    static CamelType camel_nntp_store_type = CAMEL_INVALID_TYPE;
    
    if (camel_nntp_store_type == CAMEL_INVALID_TYPE)    {
        camel_nntp_store_type = camel_type_register (CAMEL_REMOTE_STORE_TYPE, "CamelNNTPStore",
                                 sizeof (CamelNNTPStore),
                                 sizeof (CamelNNTPStoreClass),
                                 (CamelObjectClassInitFunc) camel_nntp_store_class_init,
                                 NULL,
                                 (CamelObjectInitFunc) camel_nntp_store_init,
                                 (CamelObjectFinalizeFunc) finalize);
    }
    
    return camel_nntp_store_type;
}


/**
 * camel_nntp_command: Send a command to a NNTP server.
 * @store: the NNTP store
 * @ret: a pointer to return the full server response in
 * @fmt: a printf-style format string, followed by arguments
 *
 * This command sends the command specified by @fmt and the following
 * arguments to the connected NNTP store specified by @store. It then
 * reads the server's response and parses out the status code. If
 * the caller passed a non-NULL pointer for @ret, camel_nntp_command
 * will set it to point to an buffer containing the rest of the
 * response from the NNTP server. (If @ret was passed but there was
 * no extended response, @ret will be set to NULL.) The caller must
 * free this buffer when it is done with it.
 *
 * Return value: the response code of the nntp command.
 **/
static int
camel_nntp_command_send_recv (CamelNNTPStore *store, CamelException *ex, char **ret, char *cmd)
{
    char *respbuf;
    int resp_code;
    gboolean again;

    do {
        again = FALSE;

        /* Send the command */
        if (camel_remote_store_send_string (CAMEL_REMOTE_STORE (store), ex, cmd) < 0) {
            return NNTP_PROTOCOL_ERROR;
        }

        /* Read the response */
        if (camel_remote_store_recv_line (CAMEL_REMOTE_STORE (store), &respbuf, ex) < 0) {
            if (ret)
                *ret = g_strdup (g_strerror (errno));
            return NNTP_PROTOCOL_ERROR;
        }

        resp_code = atoi (respbuf);

        /* this is kind of a gross hack, but since an auth challenge
           can pop up at any time, and we want to shield this from our
           callers, we handle authentication here. */
        if (resp_code == NNTP_AUTH_REQUIRED) {
            resp_code = camel_nntp_auth_authenticate (store, ex);
            if (resp_code != NNTP_AUTH_ACCEPTED) {
                return resp_code;
            }

            /* need to resend our command here */
            again = TRUE;
        }
    } while (again);

    if (ret) {
        *ret = strchr (respbuf, ' ');
        if (*ret)
            *ret = g_strdup (*ret + 1);
    }
    g_free (respbuf);

    return resp_code;
}

int
camel_nntp_command (CamelNNTPStore *store, CamelException *ex, char **ret, char *fmt, ...)
{
    char *cmdbuf;
    va_list ap;
    int resp_code;
    char *real_fmt;

    real_fmt = g_strdup_printf ("%s\r\n", fmt);

    va_start (ap, fmt);
    cmdbuf = g_strdup_vprintf (real_fmt, ap);
    va_end (ap);

    g_free (real_fmt);

    resp_code = camel_nntp_command_send_recv (store, ex, ret, cmdbuf);

    g_free (cmdbuf);

    return resp_code;
}

void
camel_nntp_store_subscribe_group (CamelStore *store,
                  const gchar *group_name)
{
    gchar *root_dir = camel_nntp_store_get_toplevel_dir(CAMEL_NNTP_STORE(store));
    char *ret = NULL;
    CamelException *ex = camel_exception_new();

    if (camel_exception_get_id (ex)) {
        g_free (root_dir);
        camel_exception_free (ex);
        return;
    }

    if (camel_nntp_command ( CAMEL_NNTP_STORE (store),
                 ex, &ret, "GROUP %s", group_name) == NNTP_GROUP_SELECTED) {
        /* we create an empty summary file here, so that when
                   the group is opened we'll know we need to build it. */
        gchar *summary_file;
        int fd;
        summary_file = g_strdup_printf ("%s/%s-ev-summary", root_dir, group_name);
        
        fd = open (summary_file, O_CREAT | O_RDWR, 0666);
        close (fd);

        g_free (summary_file);
    }
    if (ret) g_free (ret);

    g_free (root_dir);
    camel_exception_free (ex);
}

void
camel_nntp_store_unsubscribe_group (CamelStore *store,
                    const gchar *group_name)
{
    gchar *root_dir = camel_nntp_store_get_toplevel_dir(CAMEL_NNTP_STORE(store));
    gchar *summary_file;

    summary_file = g_strdup_printf ("%s/%s-ev-summary", root_dir, group_name);
    if (g_file_exists (summary_file))
        unlink (summary_file);
    g_free (summary_file);

    g_free (root_dir);
}

GList *
camel_nntp_store_list_subscribed_groups(CamelStore *store)
{
    GList *group_name_list = NULL;
    struct stat stat_buf;
    gint stat_error = 0;
    gchar *entry_name;
    gchar *full_entry_name;
    gchar *real_group_name;
    struct dirent *dir_entry;
    DIR *dir_handle;
    gchar *root_dir = camel_nntp_store_get_toplevel_dir(CAMEL_NNTP_STORE(store));

    dir_handle = opendir (root_dir);
    g_return_val_if_fail (dir_handle, NULL);

    /* read the first entry in the directory */
    dir_entry = readdir (dir_handle);
    while ((stat_error != -1) && (dir_entry != NULL)) {

        /* get the name of the next entry in the dir */
        entry_name = dir_entry->d_name;
        full_entry_name = g_strdup_printf ("%s/%s", root_dir, entry_name);
        stat_error = stat (full_entry_name, &stat_buf);
        g_free (full_entry_name);

        /* is it a normal file ending in -ev-summary ? */
        if ((stat_error != -1) && S_ISREG (stat_buf.st_mode)) {
            gboolean summary_suffix_found;

            real_group_name = string_prefix (entry_name, "-ev-summary",
                             &summary_suffix_found);

            if (summary_suffix_found)
                /* add the folder name to the list */
                group_name_list = g_list_append (group_name_list, 
                                 real_group_name);
        }
        /* read next entry */
        dir_entry = readdir (dir_handle);
    }

    closedir (dir_handle);

    return group_name_list;
}

gchar *
camel_nntp_store_get_toplevel_dir (CamelNNTPStore *store)
{
    CamelURL *url = CAMEL_SERVICE (store)->url;
    char *top_dir;

    g_assert(url != NULL);

    top_dir = g_strdup_printf( "%s/evolution/news/%s",
                   g_get_home_dir (),
                   url->host );

    return top_dir;
}

static gboolean
ensure_news_dir_exists (CamelNNTPStore *store)
{
    gchar *dir = camel_nntp_store_get_toplevel_dir (store);

    if (access (dir, F_OK) == 0) {
        g_free (dir);
        return TRUE;
    }

    if (camel_mkdir_hier (dir, S_IRWXU) == -1) {
        g_free (dir);
        return FALSE;
    }

    return TRUE;
}