path: root/libcaja-private/caja-dnd.c

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

/* caja-dnd.c - Common Drag & drop handling code shared by the icon container
   and the list view.

   Copyright (C) 2000, 2001 Eazel, Inc.

   The Mate Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Library General Public License as
   published by the Free Software Foundation; either version 2 of the
   License, or (at your option) any later version.

   The Mate 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
   Library General Public License for more details.

   You should have received a copy of the GNU Library General Public
   License along with the Mate Library; see the file COPYING.LIB.  If not,
   write to the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
   Boston, MA 02110-1301, USA.

   Authors: Pavel Cisler <pavel@eazel.com>,
   	    Ettore Perazzoli <ettore@gnu.org>
*/

/* FIXME: This should really be back in Caja, not here in Eel. */

#include <config.h>
#include <gtk/gtk.h>
#include <glib/gi18n.h>
#include <stdio.h>
#include <string.h>

#include <eel/eel-glib-extensions.h>
#include <eel/eel-gtk-extensions.h>
#include <eel/eel-string.h>
#include <eel/eel-vfs-extensions.h>

#include "caja-dnd.h"
#include "caja-program-choosing.h"
#include "caja-link.h"
#include "caja-window-slot-info.h"
#include "caja-window-info.h"
#include "caja-view.h"
#include "caja-file-utilities.h"

/* a set of defines stolen from the eel-icon-dnd.c file.
 * These are in microseconds.
 */
#define AUTOSCROLL_TIMEOUT_INTERVAL 100
#define AUTOSCROLL_INITIAL_DELAY 100000

/* drag this close to the view edge to start auto scroll*/
#define AUTO_SCROLL_MARGIN 30

/* the smallest amount of auto scroll used when we just enter the autoscroll
 * margin
 */
#define MIN_AUTOSCROLL_DELTA 5

/* the largest amount of auto scroll used when we are right over the view
 * edge
 */
#define MAX_AUTOSCROLL_DELTA 50

void
caja_drag_init (CajaDragInfo     *drag_info,
                const GtkTargetEntry *drag_types,
                int                   drag_type_count,
                gboolean              add_text_targets)
{
    drag_info->target_list = gtk_target_list_new (drag_types,
                             drag_type_count);

    if (add_text_targets)
    {
        gtk_target_list_add_text_targets (drag_info->target_list,
                                          CAJA_ICON_DND_TEXT);
    }

    drag_info->drop_occured = FALSE;
    drag_info->need_to_destroy = FALSE;
}

void
caja_drag_finalize (CajaDragInfo *drag_info)
{
    gtk_target_list_unref (drag_info->target_list);
    caja_drag_destroy_selection_list (drag_info->selection_list);

    g_free (drag_info);
}

/* Functions to deal with CajaDragSelectionItems.  */

CajaDragSelectionItem *
caja_drag_selection_item_new (void)
{
    return g_new0 (CajaDragSelectionItem, 1);
}

static void
drag_selection_item_destroy (CajaDragSelectionItem *item)
{
    g_free (item->uri);
    g_free (item);
}

void
caja_drag_destroy_selection_list (GList *list)
{
    GList *p;

    if (list == NULL)
        return;

    for (p = list; p != NULL; p = p->next)
        drag_selection_item_destroy (p->data);

    g_list_free (list);
}

GList *
caja_drag_uri_list_from_selection_list (const GList *selection_list)
{
    GList *uri_list;
    const GList *l;
    CajaDragSelectionItem *selection_item = NULL;

    uri_list = NULL;
    for (l = selection_list; l != NULL; l = l->next)
    {
        selection_item = (CajaDragSelectionItem *) l->data;
        if (selection_item->uri != NULL)
        {
            uri_list = g_list_prepend (uri_list, g_strdup (selection_item->uri));
        }
    }

    return g_list_reverse (uri_list);
}

GList *
caja_drag_uri_list_from_array (const char **uris)
{
    GList *uri_list;
    int i;

    if (uris == NULL)
    {
        return NULL;
    }

    uri_list = NULL;

    for (i = 0; uris[i] != NULL; i++)
    {
        uri_list = g_list_prepend (uri_list, g_strdup (uris[i]));
    }

    return g_list_reverse (uri_list);
}

GList *
caja_drag_build_selection_list (GtkSelectionData *data)
{
    GList *result;
    const guchar *p, *oldp;
    int size;

    result = NULL;
    oldp = gtk_selection_data_get_data (data);
    size = gtk_selection_data_get_length (data);

    while (size > 0)
    {
        CajaDragSelectionItem *item;
        guint len;

        /* The list is in the form:

           name\rx:y:width:height\r\n

           The geometry information after the first \r is optional.  */

        /* 1: Decode name. */

        p = memchr (oldp, '\r', size);
        if (p == NULL)
        {
            break;
        }

        item = caja_drag_selection_item_new ();

        len = p - oldp;

        item->uri = g_malloc (len + 1);
        memcpy (item->uri, oldp, len);
        item->uri[len] = 0;

        p++;
        if (*p == '\n' || *p == '\0')
        {
            result = g_list_prepend (result, item);
            if (*p != '\n')
            {
                g_warning ("Invalid x-special/mate-icon-list data received: "
                           "missing newline character.");
                break;
            }
            else
            {
                oldp = p + 1;
                continue;
            }
        }

        size -= p - oldp;
        oldp = p;

        /* 2: Decode geometry information.  */

        item->got_icon_position = sscanf (p, "%d:%d:%d:%d%*s",
                                          &item->icon_x, &item->icon_y,
                                          &item->icon_width, &item->icon_height) == 4;
        if (!item->got_icon_position)
        {
            g_warning ("Invalid x-special/mate-icon-list data received: "
                       "invalid icon position specification.");
        }

        result = g_list_prepend (result, item);

        p = memchr (p, '\r', size);
        if (p == NULL || p[1] != '\n')
        {
            g_warning ("Invalid x-special/mate-icon-list data received: "
                       "missing newline character.");
            if (p == NULL)
            {
                break;
            }
        }
        else
        {
            p += 2;
        }

        size -= p - oldp;
        oldp = p;
    }

    return g_list_reverse (result);
}

static gboolean
caja_drag_file_local_internal (const char *target_uri_string,
                               const char *first_source_uri)
{
    /* check if the first item on the list has target_uri_string as a parent
     * FIXME:
     * we should really test each item but that would be slow for large selections
     * and currently dropped items can only be from the same container
     */
    GFile *target, *item, *parent;
    gboolean result;

    result = FALSE;

    target = g_file_new_for_uri (target_uri_string);

    /* get the parent URI of the first item in the selection */
    item = g_file_new_for_uri (first_source_uri);
    parent = g_file_get_parent (item);
    g_object_unref (item);

    if (parent != NULL)
    {
        result = g_file_equal (parent, target);
        g_object_unref (parent);
    }

    g_object_unref (target);

    return result;
}

gboolean
caja_drag_uris_local (const char *target_uri,
                      const GList *source_uri_list)
{
    /* must have at least one item */
    g_assert (source_uri_list);

    return caja_drag_file_local_internal (target_uri, source_uri_list->data);
}

gboolean
caja_drag_items_local (const char *target_uri_string,
                       const GList *selection_list)
{
    /* must have at least one item */
    g_assert (selection_list);

    return caja_drag_file_local_internal (target_uri_string,
                                          ((CajaDragSelectionItem *)selection_list->data)->uri);
}

gboolean
caja_drag_items_on_desktop (const GList *selection_list)
{
    char *uri;
    GFile *desktop, *item, *parent;
    gboolean result;

    /* check if the first item on the list is in trash.
     * FIXME:
     * we should really test each item but that would be slow for large selections
     * and currently dropped items can only be from the same container
     */
    uri = ((CajaDragSelectionItem *)selection_list->data)->uri;
    if (eel_uri_is_desktop (uri))
    {
        return TRUE;
    }

    desktop = caja_get_desktop_location ();

    item = g_file_new_for_uri (uri);
    parent = g_file_get_parent (item);
    g_object_unref (item);

    result = FALSE;

    if (parent)
    {
        result = g_file_equal (desktop, parent);
        g_object_unref (parent);
    }
    g_object_unref (desktop);

    return result;

}

GdkDragAction
caja_drag_default_drop_action_for_netscape_url (GdkDragContext *context)
{
    /* Mozilla defaults to copy, however by default caja creates a link
     * if available.
     *
     * Enforced action X:
     * ((actions & X) != 0) && (suggested_action == X)
     *    - GDK_ACTION_LINK enforced by Alt
     *    - GDK_ACTION_MOVE enforced by Shift
     *    - GDK_ACTION_COPY enforced by Ctrl
     */
    GdkDragAction suggested_action = gdk_drag_context_get_suggested_action (context);
    GdkDragAction actions = gdk_drag_context_get_actions (context);
    if ((actions & GDK_ACTION_LINK) == GDK_ACTION_LINK)
    {
        return GDK_ACTION_LINK;
    }
    else if (suggested_action == GDK_ACTION_MOVE)
    {
        /* Don't support move */
        return GDK_ACTION_COPY;
    }

    return suggested_action;
}

static gboolean
check_same_fs (const char *target_uri, 
               CajaFile *target_file,
               const char *dropped_uri,
               CajaFile *dropped_file)
{
    gboolean result;

    result = FALSE;

    char *target_fs = NULL, *dropped_fs = NULL;

    if (target_file != NULL)
    {
        target_fs = caja_file_get_filesystem_id (target_file);
    }
    if (target_fs == NULL)
    {
        target_fs = caja_get_filesystem_id_by_uri (target_uri, TRUE);
    }

    if (dropped_file != NULL && !caja_file_is_symbolic_link (dropped_file))
    {
        dropped_fs = caja_file_get_filesystem_id (dropped_file);
    }
    if (dropped_fs == NULL)
    {
        dropped_fs = caja_get_filesystem_id_by_uri (dropped_uri, FALSE);
    }

    if (target_fs != NULL && dropped_fs != NULL)
    {
        result = (strcmp (target_fs, dropped_fs) == 0);
    }

    g_free (target_fs);
    g_free (dropped_fs);

    return result;
}

static gboolean
source_is_deletable (GFile *file)
{
    CajaFile *naut_file;
    gboolean ret;

    /* if there's no a cached CajaFile, it returns NULL */
    naut_file = caja_file_get_existing (file);
    if (naut_file == NULL)
    {
        return FALSE;
    }

    ret = caja_file_can_delete (naut_file);
    caja_file_unref (naut_file);

    return ret;
}

void
caja_drag_default_drop_action_for_icons (GdkDragContext *context,
        const char *target_uri_string, const GList *items,
        int *action)
{
    gboolean same_fs;
    gboolean target_is_source_parent;
    gboolean source_deletable;
    const char *dropped_uri;
    GFile *target, *dropped, *dropped_directory;
    GdkDragAction actions;
    CajaFile *dropped_file, *target_file;

    if (target_uri_string == NULL)
    {
        *action = 0;
        return;
    }

    actions = gdk_drag_context_get_actions (context) & (GDK_ACTION_MOVE | GDK_ACTION_COPY);
    if (actions == 0)
    {
        /* We can't use copy or move, just go with the suggested action. */
        *action = gdk_drag_context_get_suggested_action (context);
        return;
    }

    if (gdk_drag_context_get_suggested_action (context) == GDK_ACTION_ASK)
    {
        /* Don't override ask */
        *action = gdk_drag_context_get_suggested_action (context);
        return;
    }

    dropped_uri = ((CajaDragSelectionItem *)items->data)->uri;
    dropped_file = caja_file_get_existing_by_uri (dropped_uri);
    target_file = caja_file_get_existing_by_uri (target_uri_string);

    /*
     * Check for trash URI.  We do a find_directory for any Trash directory.
     * Passing 0 permissions as mate-vfs would override the permissions
     * passed with 700 while creating .Trash directory
     */
    if (eel_uri_is_trash (target_uri_string))
    {
        /* Only move to Trash */
        if (actions & GDK_ACTION_MOVE)
        {
            *action = GDK_ACTION_MOVE;
        }

        caja_file_unref (dropped_file);
        caja_file_unref (target_file);
        return;

    }
    else if (dropped_file != NULL && caja_file_is_launcher (dropped_file))
    {
        if (actions & GDK_ACTION_MOVE)
        {
            *action = GDK_ACTION_MOVE;
        }
        caja_file_unref (dropped_file);
        caja_file_unref (target_file);
        return;
    }
    else if (eel_uri_is_desktop (target_uri_string))
    {
        target = caja_get_desktop_location ();

        caja_file_unref (target_file);
        target_file = caja_file_get (target);

        if (eel_uri_is_desktop (dropped_uri))
        {
            /* Only move to Desktop icons */
            if (actions & GDK_ACTION_MOVE)
            {
                *action = GDK_ACTION_MOVE;
            }

            g_object_unref (target);
            caja_file_unref (dropped_file);
            caja_file_unref (target_file);
            return;
        }
    }
    else if (target_file != NULL && caja_file_is_archive (target_file))
    {
        *action = GDK_ACTION_COPY;

        caja_file_unref (dropped_file);
        caja_file_unref (target_file);
        return;
    }
    else
    {
        target = g_file_new_for_uri (target_uri_string);
    }

    same_fs = check_same_fs (target_uri_string, target_file, dropped_uri, dropped_file);

    caja_file_unref (dropped_file);
    caja_file_unref (target_file);

    /* Compare the first dropped uri with the target uri for same fs match. */
    dropped = g_file_new_for_uri (dropped_uri);
    dropped_directory = g_file_get_parent (dropped);
    target_is_source_parent = FALSE;
    if (dropped_directory != NULL)
    {
        /* If the dropped file is already in the same directory but
           is in another filesystem we still want to move, not copy
           as this is then just a move of a mountpoint to another
           position in the dir */
        target_is_source_parent = g_file_equal (dropped_directory, target);
        g_object_unref (dropped_directory);
    }
    source_deletable = source_is_deletable (dropped);

    if ((same_fs && source_deletable) || target_is_source_parent ||
            g_file_has_uri_scheme (dropped, "trash"))
    {
        if (actions & GDK_ACTION_MOVE)
        {
            *action = GDK_ACTION_MOVE;
        }
        else
        {
            *action = gdk_drag_context_get_suggested_action (context);
        }
    }
    else
    {
        if (actions & GDK_ACTION_COPY)
        {
            *action = GDK_ACTION_COPY;
        }
        else
        {
            *action = gdk_drag_context_get_suggested_action (context);
        }
    }

    g_object_unref (target);
    g_object_unref (dropped);

}

GdkDragAction
caja_drag_default_drop_action_for_uri_list (GdkDragContext *context,
        const char *target_uri_string)
{
    if (eel_uri_is_trash (target_uri_string) && (gdk_drag_context_get_actions (context) & GDK_ACTION_MOVE))
    {
        /* Only move to Trash */
        return GDK_ACTION_MOVE;
    }
    else
    {
        return gdk_drag_context_get_suggested_action (context);
    }
}

/* Encode a "x-special/mate-icon-list" selection.
   Along with the URIs of the dragged files, this encodes
   the location and size of each icon relative to the cursor.
*/
static void
add_one_mate_icon (const char *uri, int x, int y, int w, int h,
                   gpointer data)
{
    GString *result;

    result = (GString *) data;

    g_string_append_printf (result, "%s\r%d:%d:%d:%d\r\n",
                            uri, x, y, w, h);
}

/*
 * Cf. #48423
 */
#ifdef THIS_WAS_REALLY_BROKEN
static gboolean
is_path_that_mate_uri_list_extract_filenames_can_parse (const char *path)
{
    if (path == NULL || path [0] == '\0')
    {
        return FALSE;
    }

    /* It strips leading and trailing spaces. So it can't handle
     * file names with leading and trailing spaces.
     */
    if (g_ascii_isspace (path [0]))
    {
        return FALSE;
    }
    if (g_ascii_isspace (path [strlen (path) - 1]))
    {
        return FALSE;
    }

    /* # works as a comment delimiter, and \r and \n are used to
     * separate the lines, so it can't handle file names with any
     * of these.
     */
    if (strchr (path, '#') != NULL
            || strchr (path, '\r') != NULL
            || strchr (path, '\n') != NULL)
    {
        return FALSE;
    }

    return TRUE;
}

/* Encode a "text/plain" selection; this is a broken URL -- just
 * "file:" with a path after it (no escaping or anything). We are
 * trying to make the old mate_uri_list_extract_filenames function
 * happy, so this is coded to its idiosyncrasises.
 */
static void
add_one_compatible_uri (const char *uri, int x, int y, int w, int h, gpointer data)
{
    GString *result;

    result = (GString *) data;

    /* For URLs that do not have a file: scheme, there's no harm
     * in passing the real URL. But for URLs that do have a file:
     * scheme, we have to send a URL that will work with the old
     * mate-libs function or nothing will be able to understand
     * it.
     */
    if (!eel_istr_has_prefix (uri, "file:"))
    {
        g_string_append (result, uri);
        g_string_append (result, "\r\n");
    }
    else
    {
        char *local_path;

        local_path = g_filename_from_uri (uri, NULL, NULL);

        /* Check for characters that confuse the old
         * mate_uri_list_extract_filenames implementation, and just leave
         * out any paths with those in them.
         */
        if (is_path_that_mate_uri_list_extract_filenames_can_parse (local_path))
        {
            g_string_append (result, "file:");
            g_string_append (result, local_path);
            g_string_append (result, "\r\n");
        }

        g_free (local_path);
    }
}
#endif

static void
add_one_uri (const char *uri, int x, int y, int w, int h, gpointer data)
{
    GString *result;

    result = (GString *) data;

    g_string_append (result, uri);
    g_string_append (result, "\r\n");
}

/* Common function for drag_data_get_callback calls.
 * Returns FALSE if it doesn't handle drag data */
gboolean
caja_drag_drag_data_get (GtkWidget *widget,
                         GdkDragContext *context,
                         GtkSelectionData *selection_data,
                         guint info,
                         guint32 time,
                         gpointer container_context,
                         CajaDragEachSelectedItemIterator each_selected_item_iterator)
{
    GString *result;

    switch (info)
    {
    case CAJA_ICON_DND_MATE_ICON_LIST:
        result = g_string_new (NULL);
        (* each_selected_item_iterator) (add_one_mate_icon, container_context, result);
        break;

    case CAJA_ICON_DND_URI_LIST:
    case CAJA_ICON_DND_TEXT:
        result = g_string_new (NULL);
        (* each_selected_item_iterator) (add_one_uri, container_context, result);
        break;

    default:
        return FALSE;
    }

    gtk_selection_data_set (selection_data,
                            gtk_selection_data_get_target (selection_data),
                            8, result->str, result->len);
    g_string_free (result, TRUE);

    return TRUE;
}

typedef struct
{
    GMainLoop *loop;
    GdkDragAction chosen;
} DropActionMenuData;

static void
menu_deactivate_callback (GtkWidget *menu,
                          gpointer   data)
{
    DropActionMenuData *damd;

    damd = data;

    if (g_main_loop_is_running (damd->loop))
        g_main_loop_quit (damd->loop);
}

static void
drop_action_activated_callback (GtkWidget  *menu_item,
                                gpointer    data)
{
    DropActionMenuData *damd;

    damd = data;

    damd->chosen = GPOINTER_TO_INT (g_object_get_data (G_OBJECT (menu_item),
                                    "action"));

    if (g_main_loop_is_running (damd->loop))
        g_main_loop_quit (damd->loop);
}

static void
append_drop_action_menu_item (GtkWidget          *menu,
                              const char         *text,
                              GdkDragAction       action,
                              gboolean            sensitive,
                              DropActionMenuData *damd)
{
    GtkWidget *menu_item;

    menu_item = gtk_menu_item_new_with_mnemonic (text);
    gtk_widget_set_sensitive (menu_item, sensitive);
    gtk_menu_shell_append (GTK_MENU_SHELL (menu), menu_item);

    g_object_set_data (G_OBJECT (menu_item),
                       "action",
                       GINT_TO_POINTER (action));

    g_signal_connect (menu_item, "activate",
                      G_CALLBACK (drop_action_activated_callback),
                      damd);

    gtk_widget_show (menu_item);
}

/* Pops up a menu of actions to perform on dropped files */
GdkDragAction
caja_drag_drop_action_ask (GtkWidget *widget,
                           GdkDragAction actions)
{
    GtkWidget *menu;
    GtkWidget *menu_item;
    DropActionMenuData damd;

    /* Create the menu and set the sensitivity of the items based on the
     * allowed actions.
     */
    menu = gtk_menu_new ();
    gtk_menu_set_screen (GTK_MENU (menu), gtk_widget_get_screen (widget));

    append_drop_action_menu_item (menu, _("_Move Here"),
                                  GDK_ACTION_MOVE,
                                  (actions & GDK_ACTION_MOVE) != 0,
                                  &damd);

    append_drop_action_menu_item (menu, _("_Copy Here"),
                                  GDK_ACTION_COPY,
                                  (actions & GDK_ACTION_COPY) != 0,
                                  &damd);

    append_drop_action_menu_item (menu, _("_Link Here"),
                                  GDK_ACTION_LINK,
                                  (actions & GDK_ACTION_LINK) != 0,
                                  &damd);

    append_drop_action_menu_item (menu, _("Set as _Background"),
                                  CAJA_DND_ACTION_SET_AS_BACKGROUND,
                                  (actions & CAJA_DND_ACTION_SET_AS_BACKGROUND) != 0,
                                  &damd);

    eel_gtk_menu_append_separator (GTK_MENU (menu));

    menu_item = gtk_menu_item_new_with_mnemonic (_("Cancel"));
    gtk_menu_shell_append (GTK_MENU_SHELL (menu), menu_item);
    gtk_widget_show (menu_item);

    damd.chosen = 0;
    damd.loop = g_main_loop_new (NULL, FALSE);

    g_signal_connect (menu, "deactivate",
                      G_CALLBACK (menu_deactivate_callback),
                      &damd);

    gtk_grab_add (menu);

    gtk_menu_popup_at_pointer (GTK_MENU (menu), NULL);

    g_main_loop_run (damd.loop);

    gtk_grab_remove (menu);

    g_main_loop_unref (damd.loop);

    g_object_ref_sink (menu);
    g_object_unref (menu);

    return damd.chosen;
}

GdkDragAction
caja_drag_drop_background_ask (GtkWidget *widget,
                               GdkDragAction actions)
{
    GtkWidget *menu;
    GtkWidget *menu_item;
    DropActionMenuData damd;

    /* Create the menu and set the sensitivity of the items based on the
     * allowed actions.
     */
    menu = gtk_menu_new ();
    gtk_menu_set_screen (GTK_MENU (menu), gtk_widget_get_screen (widget));

    append_drop_action_menu_item (menu, _("Set as background for _all folders"),
                                  CAJA_DND_ACTION_SET_AS_GLOBAL_BACKGROUND,
                                  (actions & CAJA_DND_ACTION_SET_AS_GLOBAL_BACKGROUND) != 0,
                                  &damd);

    append_drop_action_menu_item (menu, _("Set as background for _this folder"),
                                  CAJA_DND_ACTION_SET_AS_FOLDER_BACKGROUND,
                                  (actions & CAJA_DND_ACTION_SET_AS_FOLDER_BACKGROUND) != 0,
                                  &damd);

    eel_gtk_menu_append_separator (GTK_MENU (menu));

    menu_item = gtk_menu_item_new_with_mnemonic (_("Cancel"));
    gtk_menu_shell_append (GTK_MENU_SHELL (menu), menu_item);
    gtk_widget_show (menu_item);

    damd.chosen = 0;
    damd.loop = g_main_loop_new (NULL, FALSE);

    g_signal_connect (menu, "deactivate",
                      G_CALLBACK (menu_deactivate_callback),
                      &damd);

    gtk_grab_add (menu);

    gtk_menu_popup_at_pointer (GTK_MENU (menu), NULL);

    g_main_loop_run (damd.loop);

    gtk_grab_remove (menu);

    g_main_loop_unref (damd.loop);

    g_object_ref_sink (menu);
    g_object_unref (menu);

    return damd.chosen;
}

gboolean
caja_drag_autoscroll_in_scroll_region (GtkWidget *widget)
{
    float x_scroll_delta, y_scroll_delta;

    caja_drag_autoscroll_calculate_delta (widget, &x_scroll_delta, &y_scroll_delta);

    return x_scroll_delta != 0 || y_scroll_delta != 0;
}

void
caja_drag_autoscroll_calculate_delta (GtkWidget *widget, float *x_scroll_delta, float *y_scroll_delta)
{
    GtkAllocation allocation;
    GdkDisplay *display;
    GdkSeat *seat;
    GdkDevice *pointer;
    int x, y;

    g_assert (GTK_IS_WIDGET (widget));

    display = gtk_widget_get_display (widget);
    seat = gdk_display_get_default_seat (display);
    pointer = gdk_seat_get_pointer (seat);
    gdk_window_get_device_position (gtk_widget_get_window (widget), pointer,
                                    &x, &y, NULL);

    /* Find out if we are anywhere close to the tree view edges
     * to see if we need to autoscroll.
     */
    *x_scroll_delta = 0;
    *y_scroll_delta = 0;

    if (x < AUTO_SCROLL_MARGIN)
    {
        *x_scroll_delta = (float)(x - AUTO_SCROLL_MARGIN);
    }

    gtk_widget_get_allocation (widget, &allocation);
    if (x > allocation.width - AUTO_SCROLL_MARGIN)
    {
        if (*x_scroll_delta != 0)
        {
            /* Already trying to scroll because of being too close to
             * the top edge -- must be the window is really short,
             * don't autoscroll.
             */
            return;
        }
        *x_scroll_delta = (float)(x - (allocation.width - AUTO_SCROLL_MARGIN));
    }

    if (y < AUTO_SCROLL_MARGIN)
    {
        *y_scroll_delta = (float)(y - AUTO_SCROLL_MARGIN);
    }

    if (y > allocation.height - AUTO_SCROLL_MARGIN)
    {
        if (*y_scroll_delta != 0)
        {
            /* Already trying to scroll because of being too close to
             * the top edge -- must be the window is really narrow,
             * don't autoscroll.
             */
            return;
        }
        *y_scroll_delta = (float)(y - (allocation.height - AUTO_SCROLL_MARGIN));
    }

    if (*x_scroll_delta == 0 && *y_scroll_delta == 0)
    {
        /* no work */
        return;
    }

    /* Adjust the scroll delta to the proper acceleration values depending on how far
     * into the sroll margins we are.
     * FIXME bugzilla.eazel.com 2486:
     * we could use an exponential acceleration factor here for better feel
     */
    if (*x_scroll_delta != 0)
    {
        *x_scroll_delta /= AUTO_SCROLL_MARGIN;
        *x_scroll_delta *= (MAX_AUTOSCROLL_DELTA - MIN_AUTOSCROLL_DELTA);
        *x_scroll_delta += MIN_AUTOSCROLL_DELTA;
    }

    if (*y_scroll_delta != 0)
    {
        *y_scroll_delta /= AUTO_SCROLL_MARGIN;
        *y_scroll_delta *= (MAX_AUTOSCROLL_DELTA - MIN_AUTOSCROLL_DELTA);
        *y_scroll_delta += MIN_AUTOSCROLL_DELTA;
    }

}

void
caja_drag_autoscroll_start (CajaDragInfo *drag_info,
                            GtkWidget        *widget,
                            GSourceFunc       callback,
                            gpointer          user_data)
{
    if (caja_drag_autoscroll_in_scroll_region (widget))
    {
        if (drag_info->auto_scroll_timeout_id == 0)
        {
            drag_info->waiting_to_autoscroll = TRUE;
            drag_info->start_auto_scroll_in = g_get_monotonic_time()
                                              + AUTOSCROLL_INITIAL_DELAY;

            drag_info->auto_scroll_timeout_id = g_timeout_add
                                                (AUTOSCROLL_TIMEOUT_INTERVAL,
                                                 callback,
                                                 user_data);
        }
    }
    else
    {
        if (drag_info->auto_scroll_timeout_id != 0)
        {
            g_source_remove (drag_info->auto_scroll_timeout_id);
            drag_info->auto_scroll_timeout_id = 0;
        }
    }
}

void
caja_drag_autoscroll_stop (CajaDragInfo *drag_info)
{
    if (drag_info->auto_scroll_timeout_id != 0)
    {
        g_source_remove (drag_info->auto_scroll_timeout_id);
        drag_info->auto_scroll_timeout_id = 0;
    }
}

gboolean
caja_drag_selection_includes_special_link (GList *selection_list)
{
    GList *node;

    for (node = selection_list; node != NULL; node = node->next)
    {
        char *uri;

        uri = ((CajaDragSelectionItem *) node->data)->uri;

        if (eel_uri_is_desktop (uri))
        {
            return TRUE;
        }
    }

    return FALSE;
}

static gboolean
slot_proxy_drag_motion (GtkWidget          *widget,
                        GdkDragContext     *context,
                        int                 x,
                        int                 y,
                        unsigned int        time,
                        gpointer            user_data)
{
    CajaDragSlotProxyInfo *drag_info;
    CajaWindowSlotInfo *target_slot;
    GtkWidget *window;
    GdkAtom target;
    int action;
    char *target_uri;

    drag_info = user_data;

    action = 0;

    if (gtk_drag_get_source_widget (context) == widget)
    {
        goto out;
    }

    window = gtk_widget_get_toplevel (widget);
    g_assert (CAJA_IS_WINDOW_INFO (window));

    if (!drag_info->have_data)
    {
        target = gtk_drag_dest_find_target (widget, context, NULL);

        if (target == GDK_NONE)
        {
            goto out;
        }

        gtk_drag_get_data (widget, context, target, time);
    }

    target_uri = NULL;
    if (drag_info->target_location != NULL)
    {
        target_uri = g_file_get_uri (drag_info->target_location);
    }
    else
    {
        if (drag_info->target_slot != NULL)
        {
            target_slot = drag_info->target_slot;
        }
        else
        {
            target_slot = caja_window_info_get_active_slot (CAJA_WINDOW_INFO (window));
        }

        if (target_slot != NULL)
        {
            target_uri = caja_window_slot_info_get_current_location (target_slot);
        }
    }

    if (drag_info->have_data &&
            drag_info->have_valid_data)
    {
        if (drag_info->info == CAJA_ICON_DND_MATE_ICON_LIST)
        {
            caja_drag_default_drop_action_for_icons (context, target_uri,
                    drag_info->data.selection_list,
                    &action);
        }
        else if (drag_info->info == CAJA_ICON_DND_URI_LIST)
        {
            action = caja_drag_default_drop_action_for_uri_list (context, target_uri);
        }
        else if (drag_info->info == CAJA_ICON_DND_NETSCAPE_URL)
        {
            action = caja_drag_default_drop_action_for_netscape_url (context);
        }
    }

    g_free (target_uri);

out:
    if (action != 0)
    {
        gtk_drag_highlight (widget);
    }
    else
    {
        gtk_drag_unhighlight (widget);
    }

    gdk_drag_status (context, action, time);

    return TRUE;
}

static void
drag_info_clear (CajaDragSlotProxyInfo *drag_info)
{
    if (!drag_info->have_data)
    {
        goto out;
    }

    if (drag_info->info == CAJA_ICON_DND_MATE_ICON_LIST)
    {
        caja_drag_destroy_selection_list (drag_info->data.selection_list);
    }
    else if (drag_info->info == CAJA_ICON_DND_URI_LIST)
    {
        g_list_free (drag_info->data.uri_list);
    }
    else if (drag_info->info == CAJA_ICON_DND_NETSCAPE_URL)
    {
        g_free (drag_info->data.netscape_url);
    }

out:
    drag_info->have_data = FALSE;
    drag_info->have_valid_data = FALSE;

    drag_info->drop_occured = FALSE;
}

static void
slot_proxy_drag_leave (GtkWidget          *widget,
                       GdkDragContext     *context,
                       unsigned int        time,
                       gpointer            user_data)
{
    CajaDragSlotProxyInfo *drag_info;

    drag_info = user_data;

    gtk_drag_unhighlight (widget);
    drag_info_clear (drag_info);
}

static gboolean
slot_proxy_drag_drop (GtkWidget          *widget,
                      GdkDragContext     *context,
                      int                 x,
                      int                 y,
                      unsigned int        time,
                      gpointer            user_data)
{
    GdkAtom target;
    CajaDragSlotProxyInfo *drag_info;

    drag_info = user_data;
    g_assert (!drag_info->have_data);

    drag_info->drop_occured = TRUE;

    target = gtk_drag_dest_find_target (widget, context, NULL);
    gtk_drag_get_data (widget, context, target, time);

    return TRUE;
}

static void
slot_proxy_handle_drop (GtkWidget                *widget,
                        GdkDragContext           *context,
                        unsigned int              time,
                        CajaDragSlotProxyInfo *drag_info)
{
    GtkWidget *window;
    CajaWindowSlotInfo *target_slot;
    CajaView *target_view;
    char *target_uri;

    if (!drag_info->have_data ||
            !drag_info->have_valid_data)
    {
        gtk_drag_finish (context, FALSE, FALSE, time);
        drag_info_clear (drag_info);
        return;
    }

    window = gtk_widget_get_toplevel (widget);
    g_assert (CAJA_IS_WINDOW_INFO (window));

    if (drag_info->target_slot != NULL)
    {
        target_slot = drag_info->target_slot;
    }
    else
    {
        target_slot = caja_window_info_get_active_slot (CAJA_WINDOW_INFO (window));
    }

    target_uri = NULL;
    if (drag_info->target_location != NULL)
    {
        target_uri = g_file_get_uri (drag_info->target_location);
    }
    else if (target_slot != NULL)
    {
        target_uri = caja_window_slot_info_get_current_location (target_slot);
    }

    target_view = NULL;
    if (target_slot != NULL)
    {
        target_view = caja_window_slot_info_get_current_view (target_slot);
    }

    if (target_slot != NULL && target_view != NULL)
    {
        if (drag_info->info == CAJA_ICON_DND_MATE_ICON_LIST)
        {
            GList *uri_list;

            uri_list = caja_drag_uri_list_from_selection_list (drag_info->data.selection_list);
            g_assert (uri_list != NULL);

            caja_view_drop_proxy_received_uris (target_view,
                                                uri_list,
                                                target_uri,
                                                gdk_drag_context_get_selected_action (context));
            g_list_free_full (uri_list, g_free);
        }
        else if (drag_info->info == CAJA_ICON_DND_URI_LIST)
        {
            caja_view_drop_proxy_received_uris (target_view,
                                                drag_info->data.uri_list,
                                                target_uri,
                                                gdk_drag_context_get_selected_action (context));
        }
        if (drag_info->info == CAJA_ICON_DND_NETSCAPE_URL)
        {
            caja_view_drop_proxy_received_netscape_url (target_view,
                    drag_info->data.netscape_url,
                    target_uri,
                    gdk_drag_context_get_selected_action (context));
        }

        gtk_drag_finish (context, TRUE, FALSE, time);
    }
    else
    {
        gtk_drag_finish (context, FALSE, FALSE, time);
    }

    if (target_view != NULL)
    {
        g_object_unref (target_view);
    }

    g_free (target_uri);

    drag_info_clear (drag_info);
}

static void
slot_proxy_drag_data_received (GtkWidget          *widget,
                               GdkDragContext     *context,
                               int                 x,
                               int                 y,
                               GtkSelectionData   *data,
                               unsigned int        info,
                               unsigned int        time,
                               gpointer            user_data)
{
    CajaDragSlotProxyInfo *drag_info;
    char **uris;

    drag_info = user_data;

    g_assert (!drag_info->have_data);

    drag_info->have_data = TRUE;
    drag_info->info = info;

    if (gtk_selection_data_get_length (data) < 0)
    {
        drag_info->have_valid_data = FALSE;
        return;
    }

    if (info == CAJA_ICON_DND_MATE_ICON_LIST)
    {
        drag_info->data.selection_list = caja_drag_build_selection_list (data);

        drag_info->have_valid_data = drag_info->data.selection_list != NULL;
    }
    else if (info == CAJA_ICON_DND_URI_LIST)
    {
        uris = gtk_selection_data_get_uris (data);
        drag_info->data.uri_list = caja_drag_uri_list_from_array ((const char **) uris);
        g_strfreev (uris);

        drag_info->have_valid_data = drag_info->data.uri_list != NULL;
    }
    else if (info == CAJA_ICON_DND_NETSCAPE_URL)
    {
        drag_info->data.netscape_url = g_strdup ((char *) gtk_selection_data_get_data (data));

        drag_info->have_valid_data = drag_info->data.netscape_url != NULL;
    }

    if (drag_info->drop_occured)
    {
        slot_proxy_handle_drop (widget, context, time, drag_info);
    }
}

void
caja_drag_slot_proxy_init (GtkWidget *widget,
                           CajaDragSlotProxyInfo *drag_info)
{
    const GtkTargetEntry targets[] =
    {
        { CAJA_ICON_DND_MATE_ICON_LIST_TYPE, 0, CAJA_ICON_DND_MATE_ICON_LIST },
        { CAJA_ICON_DND_NETSCAPE_URL_TYPE, 0, CAJA_ICON_DND_NETSCAPE_URL }
    };
    GtkTargetList *target_list;

    g_assert (GTK_IS_WIDGET (widget));
    g_assert (drag_info != NULL);

    gtk_drag_dest_set (widget, 0,
                       NULL, 0,
                       GDK_ACTION_MOVE |
                       GDK_ACTION_COPY |
                       GDK_ACTION_LINK |
                       GDK_ACTION_ASK);

    target_list = gtk_target_list_new (targets, G_N_ELEMENTS (targets));
    gtk_target_list_add_uri_targets (target_list, CAJA_ICON_DND_URI_LIST);
    gtk_drag_dest_set_target_list (widget, target_list);
    gtk_target_list_unref (target_list);

    g_signal_connect (widget, "drag-motion",
                      G_CALLBACK (slot_proxy_drag_motion),
                      drag_info);
    g_signal_connect (widget, "drag-drop",
                      G_CALLBACK (slot_proxy_drag_drop),
                      drag_info);
    g_signal_connect (widget, "drag-data-received",
                      G_CALLBACK (slot_proxy_drag_data_received),
                      drag_info);
    g_signal_connect (widget, "drag-leave",
                      G_CALLBACK (slot_proxy_drag_leave),
                      drag_info);
}