[nautilus] files-view: Do not copy wallpaper unnecessarily

[António Fernandes <antoniof src gnome org>]

commit 5de4c1fc74d89135100196d2a069c3797a04fc68
Author: Barnabás Pőcze <pobrn protonmail com>
Date:   Thu Jul 1 17:31:28 2021 +0200

    files-view: Do not copy wallpaper unnecessarily
    
    Previously, when an image was selected as wallpaper it would
    be copied unconditionally into the "Wallpapers" directory.
    The image would be copied even if it was already in the "Wallpapers"
    directory, resulting in copies of the image being created in
    the same directory. This made it incovenient to potentially store
    multiple backgrounds in the "Wallpapers" directory and switch
    between them due to the fact that each wallpaper change would
    result in the selected image being copied.
    
    To avoid this, introduce a check, and only copy the image
    if its parent is not the "Wallpapers" directory (as determined
    by `g_file_equal()`).
    
    For local files, `g_file_equal()` only compares the absolute
    paths - at least at the moment. Comparing paths is not enough
    to decide whether two entities are really the same in the presence
    of e.g. bind mounts. However, such configuration is arguably a
    very rare (if not non-existent). Nonetheless, users should not
    experience any regressions even in that case since when
    `g_file_equal()` returns a false negative, the old behaviour
    applies.

 src/nautilus-files-view.c | 40 ++++++++++++++++++++++++++--------------
 1 file changed, 26 insertions(+), 14 deletions(-)
---
diff --git a/src/nautilus-files-view.c b/src/nautilus-files-view.c
index 17f397322..4e57ae61e 100644
--- a/src/nautilus-files-view.c
+++ b/src/nautilus-files-view.c
@@ -6854,26 +6854,38 @@ static void
 set_wallpaper_fallback (NautilusFile *file,
                         gpointer      user_data)
 {
-    g_autofree char *target_uri = NULL;
-    GList *uris;
     g_autoptr (GFile) target = NULL;
+    g_autofree char *file_uri = NULL;
+    g_autoptr (GFile) file_parent = NULL;
 
-    /* Copy the item to Pictures/Wallpaper (internationalized) since it may be
-     *  remote. Then set it as the current wallpaper. */
+    /* Copy the item to Pictures/Wallpaper (internationalized),
+     * if it's not already there, since it may be remote.
+     * Then set it as the current wallpaper. */
     target = g_file_new_build_filename (g_get_user_special_dir (G_USER_DIRECTORY_PICTURES),
                                         _("Wallpapers"),
                                         NULL);
     g_file_make_directory_with_parents (target, NULL, NULL);
-    target_uri = g_file_get_uri (target);
-    uris = g_list_prepend (NULL, nautilus_file_get_uri (file));
-    nautilus_file_operations_copy_move (uris,
-                                        target_uri,
-                                        GDK_ACTION_COPY,
-                                        GTK_WIDGET (user_data),
-                                        NULL,
-                                        wallpaper_copy_done_callback,
-                                        NULL);
-    g_list_free_full (uris, g_free);
+
+    file_parent = nautilus_file_get_parent_location (file);
+    file_uri = nautilus_file_get_uri (file);
+
+    if (!g_file_equal (file_parent, target))
+    {
+        g_autofree char *target_uri = g_file_get_uri (target);
+        g_autoptr (GList) uris = g_list_prepend (NULL, file_uri);
+
+        nautilus_file_operations_copy_move (uris,
+                                            target_uri,
+                                            GDK_ACTION_COPY,
+                                            GTK_WIDGET (user_data),
+                                            NULL,
+                                            wallpaper_copy_done_callback,
+                                            NULL);
+    }
+    else
+    {
+        set_uri_as_wallpaper (file_uri);
+    }
 }
 
 static void