/* GIO - GLib Input, Output and Streaming Library
 *
 * Copyright (C) 2010 Collabora, Ltd.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General
 * Public License along with this library; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place, Suite 330,
 * Boston, MA 02111-1307, USA.
 *
 * Author: Nicolas Dufresne <nicolas.dufresne@collabora.co.uk>
 */

#include "config.h"

#include "gproxyresolver.h"

#include <glib.h>
#include "glibintl.h"

#include "gasyncresult.h"
#include "gcancellable.h"
#include "giomodule.h"
#include "giomodule-priv.h"
#include "gsimpleasyncresult.h"

/**
 * SECTION:gproxyresolver
 * @short_description: Asynchronous and cancellable network proxy resolver
 * @include: gio/gio.h
 *
 * #GProxyResolver provides synchronous and asynchronous network proxy
 * resolution. #GProxyResolver is used within #GSocketClient through
 * the method g_socket_connectable_proxy_enumerate().
 */

G_DEFINE_INTERFACE (GProxyResolver, g_proxy_resolver, G_TYPE_OBJECT)

static void
g_proxy_resolver_default_init (GProxyResolverInterface *iface)
{
}

static gpointer
get_default_proxy_resolver (gpointer arg)
{
  const gchar *use_this;
  GProxyResolver *resolver;
  GList *l;
  GIOExtensionPoint *ep;
  GIOExtension *extension;
  

  use_this = g_getenv ("GIO_USE_PROXY_RESOLVER");
  
  /* Ensure proxy-resolver modules loaded */
  _g_io_modules_ensure_loaded ();

  ep = g_io_extension_point_lookup (G_PROXY_RESOLVER_EXTENSION_POINT_NAME);

  if (use_this)
    {
      extension = g_io_extension_point_get_extension_by_name (ep, use_this);
      if (extension)
	{
	   resolver = g_object_new (g_io_extension_get_type (extension), NULL);
	  
	   if (g_proxy_resolver_is_supported (resolver))
	     return resolver;
	  
	  g_object_unref (resolver);
	}
    }

  for (l = g_io_extension_point_get_extensions (ep); l != NULL; l = l->next)
    {
      extension = l->data;

      resolver = g_object_new (g_io_extension_get_type (extension), NULL);

      if (g_proxy_resolver_is_supported (resolver))
	return resolver;

      g_object_unref (resolver);
    }
  
  return NULL;
}

/**
 * g_proxy_resolver_get_default:
 *
 * Gets the default #GProxyResolver for the system.
 *
 * Return value: (transfer none): the default #GProxyResolver.
 *
 * Since: 2.26
 */
GProxyResolver *
g_proxy_resolver_get_default (void)
{
  static GOnce once_init = G_ONCE_INIT;

  return g_once (&once_init, get_default_proxy_resolver, NULL);
}

/**
 * g_proxy_resolver_is_supported:
 * @resolver: a #GProxyResolver
 *
 * Checks if @resolver can be used on this system. (This is used
 * internally; g_proxy_resolver_get_default() will only return a proxy
 * resolver that returns %TRUE for this method.)
 *
 * Return value: %TRUE if @resolver is supported.
 *
 * Since: 2.26
 */
gboolean
g_proxy_resolver_is_supported (GProxyResolver *resolver)
{
  GProxyResolverInterface *iface;

  g_return_val_if_fail (G_IS_PROXY_RESOLVER (resolver), FALSE);

  iface = G_PROXY_RESOLVER_GET_IFACE (resolver);

  return (* iface->is_supported) (resolver);
}

/**
 * g_proxy_resolver_lookup:
 * @resolver: a #GProxyResolver
 * @uri: a URI representing the destination to connect to
 * @cancellable: (allow-none): a #GCancellable, or %NULL
 * @error: return location for a #GError, or %NULL
 *
 * Looks into the system proxy configuration to determine what proxy,
 * if any, to use to connect to @uri. The returned proxy URIs are of the
 * form <literal>&lt;protocol&gt;://[user[:password]@]host:port</literal>
 * or <literal>direct://</literal>, where &lt;protocol&gt; could be
 * http, rtsp, socks or other proxying protocol.
 *
 * If you don't know what network protocol is being used on the
 * socket, you should use <literal>none</literal> as the URI protocol.
 * In this case, the resolver might still return a generic proxy type
 * (such as SOCKS), but would not return protocol-specific proxy types
 * (such as http).
 *
 * <literal>direct://</literal> is used when no proxy is needed.
 * Direct connection should not be attempted unless it is part of the
 * returned array of proxies.
 *
 * Return value: (transfer full) (array zero-terminated=1): A
 *               NULL-terminated array of proxy URIs. Must be freed
 *               with g_strfreev().
 *
 * Since: 2.26
 */
gchar **
g_proxy_resolver_lookup (GProxyResolver  *resolver,
			 const gchar     *uri,
			 GCancellable    *cancellable,
			 GError         **error)
{
  GProxyResolverInterface *iface;

  g_return_val_if_fail (G_IS_PROXY_RESOLVER (resolver), NULL);
  g_return_val_if_fail (uri != NULL, NULL);

  iface = G_PROXY_RESOLVER_GET_IFACE (resolver);

  return (* iface->lookup) (resolver, uri, cancellable, error);
}

/**
 * g_proxy_resolver_lookup_async:
 * @resolver: a #GProxyResolver
 * @uri: a URI representing the destination to connect to
 * @cancellable: (allow-none): a #GCancellable, or %NULL
 * @callback: (scope async): callback to call after resolution completes
 * @user_data: (closure): data for @callback
 *
 * Asynchronous lookup of proxy. See g_proxy_resolver_lookup() for more
 * details.
 *
 * Since: 2.26
 */
void
g_proxy_resolver_lookup_async (GProxyResolver      *resolver,
			       const gchar         *uri,
			       GCancellable        *cancellable,
			       GAsyncReadyCallback  callback,
			       gpointer             user_data)
{
  GProxyResolverInterface *iface;

  g_return_if_fail (G_IS_PROXY_RESOLVER (resolver));
  g_return_if_fail (uri != NULL);

  iface = G_PROXY_RESOLVER_GET_IFACE (resolver);

  (* iface->lookup_async) (resolver, uri, cancellable, callback, user_data);
}

/**
 * g_proxy_resolver_lookup_finish:
 * @resolver: a #GProxyResolver
 * @result: the result passed to your #GAsyncReadyCallback
 * @error: return location for a #GError, or %NULL
 *
 * Call this function to obtain the array of proxy URIs when
 * g_proxy_resolver_lookup_async() is complete. See
 * g_proxy_resolver_lookup() for more details.
 *
 * Return value: (transfer full) (array zero-terminated=1): A
 *               NULL-terminated array of proxy URIs. Must be freed
 *               with g_strfreev().
 *
 * Since: 2.26
 */
gchar **
g_proxy_resolver_lookup_finish (GProxyResolver     *resolver,
				GAsyncResult       *result,
				GError            **error)
{
  GProxyResolverInterface *iface;

  g_return_val_if_fail (G_IS_PROXY_RESOLVER (resolver), NULL);

  iface = G_PROXY_RESOLVER_GET_IFACE (resolver);

  return (* iface->lookup_finish) (resolver, result, error);
}