/* GObject - GLib Type, Object, Parameter and Signal Library
 * Copyright (C) 2000 Red Hat, Inc.
 *
 * 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.
 */

#include <stdlib.h>

#include "gtypeplugin.h"
#include "gtypemodule.h"

typedef struct _ModuleTypeInfo ModuleTypeInfo;
typedef struct _ModuleInterfaceInfo ModuleInterfaceInfo;

struct _ModuleTypeInfo 
{
  gboolean  loaded;
  GType     type;
  GType     parent_type;
  GTypeInfo info;
};

struct _ModuleInterfaceInfo 
{
  gboolean       loaded;
  GType          instance_type;
  GType          interface_type;
  GInterfaceInfo info;
};

static void g_type_module_use_plugin              (GTypePlugin     *plugin);
static void g_type_module_complete_type_info      (GTypePlugin     *plugin,
						   GType            g_type,
						   GTypeInfo       *info,
						   GTypeValueTable *value_table);
static void g_type_module_complete_interface_info (GTypePlugin     *plugin,
						   GType            interface_type,
						   GType            instance_info,
						   GInterfaceInfo  *info);
 
static GObjectClass *parent_class;

static void
g_type_module_shutdown (GObject *object)
{
  GTypeModule *module = G_TYPE_MODULE (object);
  
  if (module->type_infos || module->interface_infos)
    {
      g_warning (G_STRLOC ": shutdown should never happen for static type plugins once types or interfaces have been registered");
	     
      g_object_ref (object);
    }

  parent_class->shutdown (object);
}

static void
g_type_module_finalize (GObject *object)
{
  GTypeModule *module = G_TYPE_MODULE (object);

  g_free (module->name);

  parent_class->finalize (object);
}

static void
g_type_module_class_init (GTypeModuleClass *class)
{
  GObjectClass *gobject_class = G_OBJECT_CLASS (class);

  parent_class = G_OBJECT_CLASS (g_type_class_peek_parent (class));
  
  gobject_class->shutdown = g_type_module_shutdown;
  gobject_class->finalize = g_type_module_finalize;
}

static void
g_type_module_iface_init (GTypePluginClass *iface)
{
  iface->use_plugin = g_type_module_use_plugin;
  iface->unuse_plugin = (void (*) (GTypePlugin *))g_type_module_unuse;
  iface->complete_type_info = g_type_module_complete_type_info;
  iface->complete_interface_info = g_type_module_complete_interface_info;
}

GType
g_type_module_get_type (void)
{
  static GType type_module_type = 0;

  if (!type_module_type)
    {
      static const GTypeInfo type_module_info = {
        sizeof (GTypeModuleClass),
        NULL,           /* base_init */
        NULL,           /* base_finalize */
        (GClassInitFunc) g_type_module_class_init,
        NULL,           /* class_finalize */
        NULL,           /* class_data */
        sizeof (GTypeModule),
        0,              /* n_preallocs */
        NULL,           /* instance_init */
      };
      static const GInterfaceInfo iface_info = {
        (GInterfaceInitFunc) g_type_module_iface_init,
        NULL,               /* interface_finalize */
        NULL,               /* interface_data */
      };

      type_module_type = g_type_register_static (G_TYPE_OBJECT, "GTypeModule", &type_module_info, G_TYPE_FLAG_ABSTRACT);

      g_type_add_interface_static (type_module_type, G_TYPE_TYPE_PLUGIN, &iface_info);
    }
  
  return type_module_type;
}

/**
 * g_type_module_set_name
 * @module: a #GTypeModule.
 * @name: a human-readable name to use in error messages.
 * 
 * Sets the name for a #GTypeModule 
 **/
void
g_type_module_set_name (GTypeModule  *module,
			const gchar  *name)
{
  g_return_if_fail (G_IS_TYPE_MODULE (module));

  g_free (module->name);
  module->name = g_strdup (name);
}

static ModuleTypeInfo *
g_type_module_find_type_info (GTypeModule *module,
			      GType        type)
{
  GSList *tmp_list = module->type_infos;
  while (tmp_list)
    {
      ModuleTypeInfo *type_info = tmp_list->data;
      if (type_info->type == type)
	return type_info;
      
      tmp_list = tmp_list->next;
    }

  return NULL;
}

static ModuleInterfaceInfo *
g_type_module_find_interface_info (GTypeModule *module,
				   GType        instance_type,
				   GType        interface_type)
{
  GSList *tmp_list = module->interface_infos;
  while (tmp_list)
    {
      ModuleInterfaceInfo *interface_info = tmp_list->data;
      if (interface_info->instance_type == instance_type &&
	  interface_info->interface_type == interface_type)
	return interface_info;
      
      tmp_list = tmp_list->next;
    }

  return NULL;
}

/**
 * g_type_module_use:
 * @module: a #GTypeModule
 * 
 * Increases the use count of a #GTypeModule by one. If the
 * use count was zero before, the plugin will be loaded.
 *
 * Return Value: %FALSE if the plugin needed to be loaded and
 *               loading the plugin failed.
 **/
gboolean
g_type_module_use (GTypeModule *module)
{
  g_return_val_if_fail (G_IS_TYPE_MODULE (module), FALSE);

  module->use_count++;
  if (module->use_count == 1)
    {
      GSList *tmp_list;
      
      if (!G_TYPE_MODULE_GET_CLASS (module)->load (module))
	{
	  module->use_count--;
	  return FALSE;
	}

      tmp_list = module->type_infos;
      while (tmp_list)
	{
	  ModuleTypeInfo *type_info = tmp_list->data;
	  if (!type_info->loaded)
	    {
	      g_warning ("plugin '%s' failed to register type '%s'\n",
			 module->name ? module->name : "(unknown)",
			 g_type_name (type_info->type));
	      return FALSE;
	    }
	  
	  tmp_list = tmp_list->next;
	}
    }
 
  return TRUE;
}

/**
 * g_type_module_unuse:
 * @module: a #GTypeModule
 * 
 * Decreases the use count of a #GTypeModule by one. If the
 * result is zero, the module will be unloaded. (However, the
 * #GTypeModule will not be freed, and types associated with the
 * #GTypeModule are not unregistered. Once a #GTypeModule is 
 * initialized, it must exist forever.)
 **/
void
g_type_module_unuse (GTypeModule *module)
{
  g_return_if_fail (G_IS_TYPE_MODULE (module));
  g_return_if_fail (module->use_count > 0);

  module->use_count--;

  if (module->use_count == 0)
    {
      GSList *tmp_list;

      G_TYPE_MODULE_GET_CLASS (module)->unload (module);

      tmp_list = module->type_infos;
      while (tmp_list)
	{
	  ModuleTypeInfo *type_info = tmp_list->data;
	  type_info->loaded = FALSE;

	  tmp_list = tmp_list->next;
	}
    }
}
	
static void
g_type_module_use_plugin (GTypePlugin *plugin)
{
  GTypeModule *module = G_TYPE_MODULE (plugin);

  if (!g_type_module_use (module))
    {
      g_warning ("Fatal error - Could not reload previously loaded plugin '%s'\n",
		 module->name ? module->name : "(unknown)");
      exit (1);
    }
}

static void
g_type_module_complete_type_info (GTypePlugin     *plugin,
				  GType            g_type,
				  GTypeInfo       *info,
				  GTypeValueTable *value_table)
{
  GTypeModule *module = G_TYPE_MODULE (plugin);
  ModuleTypeInfo *module_type_info = g_type_module_find_type_info (module, g_type);

  *info = module_type_info->info;
  
  if (module_type_info->info.value_table)
    *value_table = *module_type_info->info.value_table;
}

static void 
g_type_module_complete_interface_info (GTypePlugin    *plugin,
				       GType           interface_type,
				       GType           instance_type,
				       GInterfaceInfo *info)
{
  GTypeModule *module = G_TYPE_MODULE (plugin);
  ModuleInterfaceInfo *module_interface_info = g_type_module_find_interface_info (module, interface_type, instance_type);

  *info = module_interface_info->info;
}

/**
 * g_type_module_register_type:
 * @module:  a #GTypeModule
 * @parent_type:    the type for the parent class
 * @type_name:      name for the type
 * @type_info:      type information structure
 * @flags:          flags field providing details about the type           
 * 
 * Looks up or registers a type that is implemented with a particular
 * type plugin. If a type with name @type_name is already registered,
 * the #GType identifier for the type is returned, otherwise the type
 * is newly registered, and the resulting #GType identifier returned.
 *
 * As long as any instances of the type exist, the type plugin will
 * not be unloaded.
 *
 * Return value: the type ID for the class.
 **/
GType
g_type_module_register_type (GTypeModule     *module,
			     GType            parent_type,
			     const gchar     *type_name,
			     const GTypeInfo *type_info,
			     GTypeFlags       flags)
{
  ModuleTypeInfo *module_type_info = NULL;
  GType type;
  
  g_return_val_if_fail (module != NULL, 0);
  g_return_val_if_fail (type_name != NULL, 0);
  g_return_val_if_fail (type_info != NULL, 0);

  type = g_type_from_name (type_name);
  if (type)
    {
      GTypePlugin *old_plugin = g_type_get_plugin (type);

      if (old_plugin != G_TYPE_PLUGIN (module))
	{
	  g_warning ("Two different plugins tried to register '%s'.", type_name);
	  return 0;
	}
    }

  if (type)
    {
      module_type_info = g_type_module_find_type_info (module, type);

      if (module_type_info->parent_type != parent_type)
	{
	  const gchar *parent_type_name = g_type_name (parent_type);
	  
	  g_warning ("Type '%s' recreated with different parent type.\n"
		     "(was '%s', now '%s')", type_name,
		     g_type_name (module_type_info->parent_type),
		     parent_type_name ? parent_type_name : "(unknown)");
	  return 0;
	}
    }
  else
    {
      module_type_info = g_new (ModuleTypeInfo, 1);
      
      module_type_info->parent_type = parent_type;
      module_type_info->type = g_type_register_dynamic (parent_type, type_name, G_TYPE_PLUGIN (module), flags);
      
      module->type_infos = g_slist_prepend (module->type_infos, module_type_info);
    }

  module_type_info->loaded = TRUE;
  module_type_info->info = *type_info;
  if (type_info->value_table)
    module_type_info->info.value_table = g_memdup (type_info->value_table,
						   sizeof (type_info->value_table));

  return module_type_info->type;
}

/**
 * g_type_module_add_interface:
 * @module: a #GTypeModule
 * @instance_type: type to which to add the interface.
 * @interface_type: interface type to add
 * @interface_info: type information structure
 * 
 * Registers an additional interface for a type, whose interface
 * lives in the given type plugin. If the interface was already registered
 * for the type in this plugin, nothing will be done. 
 *
 * As long as any instances of the type exist, the type plugin will
 * not be unloaded.
 **/
void
g_type_module_add_interface (GTypeModule    *module,
			     GType           instance_type,
			     GType           interface_type,
			     GInterfaceInfo *interface_info)
{
  ModuleInterfaceInfo *module_interface_info = NULL;
  
  g_return_if_fail (module != NULL);
  g_return_if_fail (interface_info != NULL);

  if (g_type_conforms_to (instance_type, interface_type))
    {
      GTypePlugin *old_plugin = g_type_interface_get_plugin (instance_type,
							     interface_type);

      if (!old_plugin)
	{
	  g_warning ("Interface '%s' for '%s' was previously registered statically or for a parent type.",
		     g_type_name (interface_type), g_type_name (instance_type));
	  return;
	}
      else if (old_plugin != G_TYPE_PLUGIN (module))
	{
	  g_warning ("Two different plugins tried to register interface '%s' for '%s'.",
		     g_type_name (interface_type), g_type_name (instance_type));
	  return;
	}
      
      module_interface_info = g_type_module_find_interface_info (module, instance_type, interface_type);

      g_assert (module_interface_info);
    }
  else
    {
      module_interface_info = g_new (ModuleInterfaceInfo, 1);
      
      module_interface_info->instance_type = instance_type;
      module_interface_info->interface_type = interface_type;
      
      g_type_add_interface_dynamic (instance_type, interface_type, G_TYPE_PLUGIN (module));
      
      module->interface_infos = g_slist_prepend (module->interface_infos, module_interface_info);
    }
  
  module_interface_info->loaded = TRUE;
  module_interface_info->info = *interface_info;
}