path: root/camel/camel-provider.c

/* -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*- */
/* camel-provider.c :  provider framework   */

/* 
 *
 * Copyright (C) 1999 Bertrand Guiheneuf <Bertrand.Guiheneuf@aful.org> .
 *
 * 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
 */


/* 
   A provider can be added "by hand" or by loading a module. 


   Adding providers with modules. 
   ------------------------------

   The modules are shared libraries which must contain the 
   function

   CamelProvider *camel_provider_module_init ();
  
   returning the provider object defined in the module 

   
*/

/* FIXME: Shouldn't we add a version number to providers ? */

#include "config.h"
#include "camel-provider.h"
#include "camel-log.h"


static GList *_provider_list = NULL;
static gchar *_last_error;

static gint        
_provider_name_cmp (gconstpointer a, gconstpointer b)
{
    CamelProvider *provider_a = CAMEL_PROVIDER (a);
    CamelProvider *provider_b = CAMEL_PROVIDER (b);

    return strcmp ( provider_a->name,  provider_b->name);
}

void
camel_provider_register (CamelProvider *provider)
{
    GList *old_provider_node = NULL;

    g_assert (provider);
    
    if (_provider_list)
        old_provider_node = g_list_find_custom (_provider_list, provider, _provider_name_cmp);

    if (old_provider_node != NULL) {
        // camel_provider_unref (CAMEL_PROVIDER (old_provider_node->data));
        old_provider_node->data = provider;
    } else {
        /* be careful, we use prepend here, so that last registered
           providers come first */
        _provider_list = g_list_prepend (_provider_list, provider);
    }
    // camel_provider_ref (provider);
    
}


const CamelProvider *
camel_provider_register_as_module (const gchar *module_path)
{
    
    CamelProvider *new_provider = NULL;
    GModule *new_module = NULL;
    CamelProvider * (*camel_provider_module_init) ();
    gboolean has_module_init;
    
    CAMEL_LOG_FULL_DEBUG ("Entering CamelProvider::register_as_module\n");
    
    g_return_val_if_fail (module_path, NULL);

    if (!g_module_supported ()) {
        CAMEL_LOG_WARNING ("CamelProvider::register_as_module module loading not supported on this system\n");
        CAMEL_LOG_FULL_DEBUG ("Leaving CamelProvider::register_as_module\n");
        return NULL;
    }
    

    new_module = g_module_open (module_path, 0);
    if (!new_module) {
        CAMEL_LOG_WARNING ("CamelProvider::register_as_module Unable to load module %s\n", module_path);
        CAMEL_LOG_FULL_DEBUG ("Leaving CamelProvider::register_as_module\n");
        return NULL;
    }
        
    has_module_init = g_module_symbol (new_module, "camel_provider_module_init", (gpointer *)&camel_provider_module_init);
    if (!has_module_init){
        CAMEL_LOG_WARNING ("CamelProvider::register_as_module loading of module %s failed,\n"
                   "\t Symbol camel_provider_module_init not defined in it\n", module_path);
        CAMEL_LOG_FULL_DEBUG ("Leaving CamelProvider::register_as_module\n");
        return NULL;
    }

    new_provider = camel_provider_module_init();
    new_provider->gmodule = new_module;

    CAMEL_LOG_FULL_DEBUG ("Leaving CamelProvider::register_as_module\n");
    return new_provider;

 
} 




/* 
   be careful to this function, @a is expected to be
   a provider, @b a protocol name (const gchar *)
*/
static gint        
_provider_protocol_find (gconstpointer a, gconstpointer b)
{
    CamelProvider *provider_a = CAMEL_PROVIDER (a);
    const gchar *name_b = (const gchar *)b;

    return g_strcasecmp ( provider_a->name, name_b);
}

/**
 * camel_provider_get_for_protocol: get a registered provider for a protocol
 * @protocol: protocol name (case insensitive)
 * @type: provider type (transport, store, ...)
 * 
 * Look into the list of registered provider if 
 * one correspond both to the protocol name 
 * and to the protocol type. When several providerss
 * exist for a same protocol, the last registered
 * is returned.
 * 
 * Return value: Matching provider or NULL if none exists. 
 **/
const CamelProvider *
camel_provider_get_for_protocol (const gchar *protocol, ProviderType type)
{
    GList *found_provider_node;
    CamelProvider *found_provider = NULL;
    
    g_assert (protocol);
    g_return_val_if_fail (_provider_list, NULL);
     
    /* we've got a compilation warning here because of bad prototype of
       g_list_find_custom (), don't worry about that */
    do {
        found_provider_node = g_list_find_custom (_provider_list, (gconstpointer)protocol, _provider_name_cmp);
        /* we will get the last registered provider 
           here because providers are registered 
           using g_list_prepend(). This is a bit
           dangerous however because we rely on 
           the way g_list_find_custom() is implemented.
           This should be changed one day */        
        if (found_provider_node)
            found_provider = (CamelProvider*)found_provider_node->data;
        else found_provider = NULL;
    }
    while (found_provider && (found_provider->provider_type != type));
    
    return found_provider;
}