nautilus/nautilus-sysadmin-desktop-items.diff

Sysadmin-defined desktop items for Nautilus
http://www.gnome.org/~federico/news-2008-08.html#nautilus-predefined-desktop-items

diff --git a/libnautilus-private/apps_nautilus_preferences.schemas.in b/libnautilus-private/apps_nautilus_preferences.schemas.in
index ca45081..c180132 100644
--- a/libnautilus-private/apps_nautilus_preferences.schemas.in
+++ b/libnautilus-private/apps_nautilus_preferences.schemas.in
@@ -1072,5 +1072,21 @@ most cases, this should be left alone. -->Sans 10</default>
       </locale>
     </schema>
 
+    <schema>
+      <key>/schemas/apps/nautilus/desktop/predefined_items_dir</key>
+      <applyto>/apps/nautilus/desktop/predefined_items_dir</applyto>
+      <owner>nautilus</owner>
+      <type>string</type>
+      <locale name="C">
+      	<short>Directory for storing predefined desktop items</short>
+	<long>
+	  Desktop files (*.desktop) which appear in this directory
+	  will be shown on the user's desktop.  System administrators
+	  can use this feature to define desktop shortcuts which
+	  appear for users.
+	</long>
+      </locale>
+    </schema>
+
   </schemalist>  
 </gconfschemafile>
diff --git a/libnautilus-private/nautilus-debug-log.c b/libnautilus-private/nautilus-debug-log.c
index f4ce320..ad84b4b 100644
--- a/libnautilus-private/nautilus-debug-log.c
+++ b/libnautilus-private/nautilus-debug-log.c
@@ -222,6 +222,14 @@ nautilus_debug_log_with_uri_list (gboolean is_milestone, const char *domain, con
 				  const char *format, ...)
 {
 	va_list args;
+	GList node;
+
+	if (!uris) {
+		node.data = "[no files]";
+		node.prev = NULL;
+		node.next = NULL;
+		uris = &node;
+	}
 
 	va_start (args, format);
 	nautilus_debug_logv (is_milestone, domain, uris, format, args);
@@ -235,6 +243,7 @@ nautilus_debug_log_with_file_list (gboolean is_milestone, const char *domain, GL
 	va_list args;
 	GList *uris;
 	GList *l;
+	GList node;
 
 	uris = NULL;
 
@@ -260,11 +269,20 @@ nautilus_debug_log_with_file_list (gboolean is_milestone, const char *domain, GL
 
 	uris = g_list_reverse (uris);
 
+	if (!uris) {
+		node.data = "[no files]";
+		node.prev = NULL;
+		node.next = NULL;
+		uris = &node;
+	}
+
 	va_start (args, format);
 	nautilus_debug_logv (is_milestone, domain, uris, format, args);
 	va_end (args);
 
-	eel_g_list_free_deep (uris);
+	if (uris != &node) {
+		eel_g_list_free_deep (uris);
+	}
 }
 
 gboolean
diff --git a/libnautilus-private/nautilus-debug-log.h b/libnautilus-private/nautilus-debug-log.h
index ad0152e..7ed1af1 100644
--- a/libnautilus-private/nautilus-debug-log.h
+++ b/libnautilus-private/nautilus-debug-log.h
@@ -27,10 +27,12 @@
 
 #include <glib.h>
 
-#define NAUTILUS_DEBUG_LOG_DOMAIN_USER		"USER"   /* always enabled */
-#define NAUTILUS_DEBUG_LOG_DOMAIN_ASYNC		"async"	 /* when asynchronous notifications come in */
-#define NAUTILUS_DEBUG_LOG_DOMAIN_GLOG          "GLog"	 /* used for GLog messages; don't use it yourself */
-#define NAUTILUS_DEBUG_LOG_DOMAIN_LOCKDOWN	"lockdown"	/* when things get *not* done due to lockdown */
+#define NAUTILUS_DEBUG_LOG_DOMAIN_USER			"USER"			/* always enabled */
+#define NAUTILUS_DEBUG_LOG_DOMAIN_ASYNC			"async"			/* when asynchronous notifications come in */
+#define NAUTILUS_DEBUG_LOG_DOMAIN_GLOG			"GLog"			/* used for GLog messages; don't use it yourself */
+#define NAUTILUS_DEBUG_LOG_DOMAIN_LOCKDOWN		"lockdown"		/* when things get *not* done due to lockdown */
+#define NAUTILUS_DEBUG_LOG_DOMAIN_DESKTOP_ITEMS 	"desktop-items"		/* used for predefined desktop items (this is useful for sysadmins) */
+#define NAUTILUS_DEBUG_LOG_DOMAIN_DEBUG_DESKTOP_ITEMS	"debug-desktop-items"	/* debugging the machinery for predefined desktop items */
 
 void nautilus_debug_log (gboolean is_milestone, const char *domain, const char *format, ...);
 
diff --git a/libnautilus-private/nautilus-desktop-directory.c b/libnautilus-private/nautilus-desktop-directory.c
index 0c5333e..b08abef 100644
--- a/libnautilus-private/nautilus-desktop-directory.c
+++ b/libnautilus-private/nautilus-desktop-directory.c
@@ -24,34 +24,83 @@
    Author: Alexander Larsson <alexl@redhat.com>
 */
 
+/* Note that we use two debug domains here:
+ *   NAUTILUS_DEBUG_LOG_DOMAIN_DESKTOP_ITEMS       - "desktop-items"
+ *   NAUTILUS_DEBUG_LOG_DOMAIN_DEBUG_DESKTOP_ITEMS - "debug-desktop-items"
+ *
+ * The first one is logged as a milestone during initialization, and is actually useful to the sysadmin if he wants to
+ * debug his predefined desktop items:  the log will contain info on which items are defined to be mandatory or not.
+ *
+ * The second one is internal to Nautilus, and is used for debugging purposes only (it traces the code flow among the
+ * interesting parts of this source file).
+ */
+
 #include <config.h>
 #include "nautilus-desktop-directory.h"
 
+#include "nautilus-debug-log.h"
 #include "nautilus-directory-private.h"
 #include "nautilus-file.h"
 #include "nautilus-file-private.h"
 #include "nautilus-file-utilities.h"
 #include "nautilus-global-preferences.h"
 #include <eel/eel-glib-extensions.h>
+#include <glib/gi18n.h>
 #include <gtk/gtk.h>
+#include <libgnome/gnome-desktop-item.h>
 #include <libgnome/gnome-macros.h>
 
 struct NautilusDesktopDirectoryDetails {
 	NautilusDirectory *real_directory;
+	NautilusDirectory *predefined_items_dir;
 	GHashTable *callbacks;
 	GHashTable *monitors;
+
+	/* We store the "combined" files from the real_directory and the
+	 * predefined_items_dir in the name_to_pairs_hash table.
+	 *
+	 * The hash table maps strings (file names) to FilePair structs.  The
+	 * strings live in the "name" field of those structs, to make memory
+	 * management easier (i.e. the keys in the hash table need not to be
+	 * memory-managed separately).
+	 *
+	 * We use the hash to answer the question, "do we already have a file
+	 * with this name?", as the predefined items override the user's items
+	 * (or vice-versa) based on matching filenames.
+	 *
+	 * The file_to_pairs_hash answers the question, "do we have a pair
+	 * (which one?) for the specified file?".
+	 *
+	 * Within a FilePair in name_to_pairs_hash, both files are ref'ed.
+	 *
+	 * Within file_to_pairs_hash, the "key" file is *NOT* ref'ed, since it
+	 * is already ref'ed by a corresponding FilePair.
+	 */
+	GHashTable *name_to_pairs_hash;
+	GHashTable *file_to_pairs_hash;
+
+	eel_boolean_bit files_are_combined : 1;
+	eel_boolean_bit initializing : 1;
+	eel_boolean_bit real_directory_pending : 1;
+	eel_boolean_bit predefined_items_dir_pending : 1;
 };
 
+/* Structs of this type are stored in NautilusDesktopDirectory->name_to_pairs_hash */
+typedef struct {
+	char *name;
+
+	NautilusFile *user_file;
+	NautilusFile *predefined_file;
+
+	gboolean predefined_overrides_user;
+} FilePair;
+
 typedef struct {
 	NautilusDesktopDirectory *desktop_dir;
 	NautilusDirectoryCallback callback;
 	gpointer callback_data;
 
-	NautilusFileAttributes wait_for_attributes;
-	gboolean wait_for_file_list;
-
 	GList *non_ready_directories;
-	GList *merged_file_list;
 } MergedCallback;
 
 
@@ -64,24 +113,48 @@ typedef struct {
 } MergedMonitor;
 
 static void desktop_directory_changed_callback (gpointer data);
+static GList *desktop_get_file_list (NautilusDirectory *directory);
+
+static gboolean directories_are_done_loading (NautilusDesktopDirectory *directory);
+static void predefined_items_dir_changed_callback (gpointer data);
 
 GNOME_CLASS_BOILERPLATE (NautilusDesktopDirectory, nautilus_desktop_directory,
 			 NautilusDirectory, NAUTILUS_TYPE_DIRECTORY)
 
+static gboolean
+pair_shows_file (FilePair *pair, NautilusFile *file)
+{
+	return ((file == pair->user_file && !pair->predefined_overrides_user)
+		|| (file == pair->predefined_file && pair->predefined_overrides_user));
+}
 
 static gboolean
 desktop_contains_file (NautilusDirectory *directory,
 		       NautilusFile *file)
 {
 	NautilusDesktopDirectory *desktop;
+	FilePair *pair;
+	gboolean result;
+	char *uri;
 
 	desktop = NAUTILUS_DESKTOP_DIRECTORY (directory);
 
-	if (nautilus_directory_contains_file (desktop->details->real_directory, file)) {
-		return TRUE;
+	pair = g_hash_table_lookup (desktop->details->file_to_pairs_hash, file);
+
+	if (pair != NULL) {
+		result = pair_shows_file (pair, file);
+	} else {
+		result = file->details->directory == directory; /* this is just for desktop links from NautilusDesktopLinkMonitor */
 	}
 
-	return file->details->directory == directory;
+	uri = nautilus_file_get_uri (file);
+	nautilus_debug_log (FALSE, NAUTILUS_DEBUG_LOG_DOMAIN_DEBUG_DESKTOP_ITEMS,
+			    "desktop_contains_file (%s): %d",
+			    uri,
+			    result);
+	g_free (uri);
+
+	return result;
 }
 
 static guint
@@ -114,15 +187,72 @@ merged_callback_destroy (MergedCallback *merged_callback)
 	g_assert (NAUTILUS_IS_DESKTOP_DIRECTORY (merged_callback->desktop_dir));
 
 	g_list_free (merged_callback->non_ready_directories);
-	nautilus_file_list_free (merged_callback->merged_file_list);
 	g_free (merged_callback);
 }
 
 static void
+add_file_from_pair_to_list_cb (gpointer key, gpointer value, gpointer data)
+{
+	FilePair *pair;
+	GList **list_ptr;
+	NautilusFile *file;
+
+	pair = value;
+	list_ptr = data;
+
+	file = pair->predefined_overrides_user ? pair->predefined_file : pair->user_file;
+	nautilus_file_ref (file);
+
+	*list_ptr = g_list_prepend (*list_ptr, file);
+}
+
+static GList *
+get_combined_files (NautilusDesktopDirectory *desktop)
+{
+	GList *combined;
+
+	combined = NULL;
+	g_hash_table_foreach (desktop->details->name_to_pairs_hash, add_file_from_pair_to_list_cb, &combined);
+	return combined;
+}
+
+static GList *
+get_desktop_links (NautilusDesktopDirectory *desktop, gboolean include_tentative_files)
+{
+	if (include_tentative_files) {
+		return nautilus_file_list_copy (NAUTILUS_DIRECTORY (desktop)->details->file_list);
+	} else {
+		/* This is because nautilus-directory.c:real_get_file_list() stripts out the tentative files */
+		return GNOME_CALL_PARENT_WITH_DEFAULT (NAUTILUS_DIRECTORY_CLASS, get_file_list, (NAUTILUS_DIRECTORY (desktop)), NULL);
+	}
+}
+
+static GList *
+get_file_list (NautilusDesktopDirectory *desktop, gboolean include_tentative_files)
+{
+	GList *combined_file_list;
+	GList *file_list_from_desktop_links;
+
+	combined_file_list = get_combined_files (desktop);
+
+	file_list_from_desktop_links = get_desktop_links (desktop, include_tentative_files);
+
+	combined_file_list = g_list_concat (combined_file_list, file_list_from_desktop_links);
+
+	return combined_file_list;
+
+}
+
+static void
 merged_callback_check_done (MergedCallback *merged_callback)
 {
+	NautilusDesktopDirectory *desktop;
+	GList *files;
+
+	desktop = merged_callback->desktop_dir;
+
 	/* Check if we are ready. */
-	if (merged_callback->non_ready_directories != NULL) {
+	if (merged_callback->non_ready_directories != NULL || !desktop->details->files_are_combined) {
 		return;
 	}
 
@@ -130,10 +260,18 @@ merged_callback_check_done (MergedCallback *merged_callback)
 	g_hash_table_steal (merged_callback->desktop_dir->details->callbacks, merged_callback);
 
 	/* We are ready, so do the real callback. */
-	(* merged_callback->callback) (NAUTILUS_DIRECTORY (merged_callback->desktop_dir),
-				       merged_callback->merged_file_list,
+
+	files = get_file_list (NAUTILUS_DIRECTORY (desktop), TRUE);
+
+	nautilus_debug_log_with_file_list (FALSE, NAUTILUS_DEBUG_LOG_DOMAIN_DEBUG_DESKTOP_ITEMS, files,
+					   "merged_callback_check_done: we are done; calling callback with files");
+
+	(* merged_callback->callback) (NAUTILUS_DIRECTORY (desktop),
+				       files,
 				       merged_callback->callback_data);
 
+	nautilus_file_list_free (files);
+
 	/* And we are done. */
 	merged_callback_destroy (merged_callback);
 }
@@ -144,7 +282,330 @@ merged_callback_remove_directory (MergedCallback *merged_callback,
 {
 	merged_callback->non_ready_directories = g_list_remove
 		(merged_callback->non_ready_directories, directory);
-	merged_callback_check_done (merged_callback);
+}
+
+static FilePair *
+create_file_pair (NautilusDesktopDirectory *desktop, NautilusFile *file, gboolean is_predefined, gboolean *is_new_pair)
+{
+	char *name;
+	FilePair *pair;
+
+	/* Sanity check */
+
+	pair = g_hash_table_lookup (desktop->details->file_to_pairs_hash, file);
+	g_assert (pair == NULL);
+
+	/* Create the pair or add to it */
+
+	name = nautilus_file_get_name (file);
+
+	pair = g_hash_table_lookup (desktop->details->name_to_pairs_hash, name);
+
+	nautilus_file_ref (file);
+
+	if (pair == NULL) {
+		if (is_new_pair) {
+			*is_new_pair = TRUE;
+		}
+
+		pair = g_slice_new (FilePair);
+
+		pair->name            = name;
+		pair->user_file       = is_predefined ? NULL : file;
+		pair->predefined_file = is_predefined ? file : NULL;
+
+		pair->predefined_overrides_user = FALSE; /* we don't know yet */
+
+		g_hash_table_insert (desktop->details->name_to_pairs_hash, name, pair);
+	} else {
+		if (is_new_pair) {
+			*is_new_pair = FALSE;
+		}
+
+		g_free (name);
+
+		if (is_predefined) {
+			g_assert (pair->predefined_file == NULL);
+			pair->predefined_file = file;
+		} else {
+			g_assert (pair->user_file == NULL);
+			pair->user_file = file;
+		}
+	}
+
+	g_hash_table_insert (desktop->details->file_to_pairs_hash, file, pair);
+
+	return pair;
+}
+
+static void
+log_pair (FilePair *pair, gboolean is_new_pair)
+{
+	nautilus_debug_log (FALSE, NAUTILUS_DEBUG_LOG_DOMAIN_DEBUG_DESKTOP_ITEMS,
+			    "%s pair %p: %s - predefined=%p user=%p predefined_overrides_user=%d",
+			    is_new_pair ? "New" : "Existing",
+			    pair,
+			    pair->name,
+			    pair->predefined_file,
+			    pair->user_file,
+			    pair->predefined_overrides_user);
+}
+
+static void
+create_file_pairs_for_directory (NautilusDesktopDirectory *desktop, NautilusDirectory *directory, gboolean is_predefined)
+{
+	GList *list;
+	GList *l;
+
+	if (directory == NULL) {
+		return;
+	}
+
+	list = nautilus_directory_get_file_list (directory);
+
+	nautilus_debug_log_with_file_list (FALSE, NAUTILUS_DEBUG_LOG_DOMAIN_DEBUG_DESKTOP_ITEMS, list,
+					   "create_file_pairs_for_directory(): Creating pairs for files");
+
+	for (l = list; l; l = l->next) {
+		FilePair *pair;
+		gboolean is_new_pair;
+
+		pair = create_file_pair (desktop, NAUTILUS_FILE (l->data), is_predefined, &is_new_pair);
+		log_pair (pair, is_new_pair);
+	}
+
+	nautilus_file_list_free (list);
+}
+
+static char *
+get_file_contents (NautilusFile *file, gsize *length, GError **error)
+{
+	GFile *location;
+	char *path;
+	char *contents;
+
+	location = nautilus_file_get_location (file);
+	path = g_file_get_path (location);
+	contents = NULL;
+
+	if (path == NULL) {
+		char *uri;
+
+		uri = g_file_get_uri (location);
+		g_set_error (error,
+			     G_IO_ERROR,
+			     G_IO_ERROR_FAILED,
+			     _("Cannot read remote item: %s"),
+			     uri);
+		g_free (uri);
+			     
+		goto out;
+	}
+
+	if (!g_file_get_contents (path, &contents, length, error)) {
+		contents = NULL;
+	}
+
+out:
+	return contents;
+}
+
+static gboolean
+predefined_desktop_item_is_mandatory (GnomeDesktopItem *item)
+{
+	/* If the desktop item does not have X-XDG-Is-Mandatory defined, then we
+	 * assume it to be mandatory.  This is so that the sysadmin can just
+	 * copy existing .desktop files into the directory for predefined items,
+	 * and assume that they will override anything the user tries to use.
+	 */
+	return (!gnome_desktop_item_attr_exists (item, "X-XDG-Is-Mandatory")
+		|| gnome_desktop_item_get_boolean (item, "X-XDG-Is-Mandatory"));
+}
+
+static gboolean
+predefined_file_should_override_user_file (NautilusDesktopDirectory *desktop, NautilusFile *predefined, NautilusFile *user)
+{
+	gsize predefined_length;
+	char *predefined_contents;
+	char *predefined_uri;
+	char *user_uri;
+	GnomeDesktopItem *predefined_item;
+	GError *error;
+	gboolean should_override;
+	time_t predefined_mtime, user_mtime;
+	const char *reason;
+
+	should_override = FALSE;
+	reason = "the predefined item is not mandatory";
+
+	predefined_uri = nautilus_file_get_uri (predefined);
+	user_uri = nautilus_file_get_uri (user);
+	predefined_item = NULL;
+
+	/* Can we discard either file trivially? */
+
+	if (!nautilus_file_is_mime_type (predefined, "application/x-desktop")) {
+		reason = "predefined items which are not .desktop files always override user items";
+		should_override = TRUE;
+		goto out;
+	}
+
+	if (!nautilus_file_is_mime_type (user, "application/x-desktop")) {
+		reason = "predefined items always override user items that are not .desktop files";
+		should_override = TRUE;
+		goto out;
+	}
+
+	/* Read the predefined .desktop file */
+
+	/* FIXME: reading the file asynchronously is left as an exercise for the reader */
+
+	error = NULL;
+	predefined_contents = get_file_contents (predefined, &predefined_length, &error);
+	if (predefined_contents == NULL) {
+		/* can't determine contents trivially?  let it override the user's stuff, anyway */
+		nautilus_directory_emit_load_error (NAUTILUS_DIRECTORY (desktop), error);
+		nautilus_debug_log (desktop->details->initializing, NAUTILUS_DEBUG_LOG_DOMAIN_DESKTOP_ITEMS,
+				    "Error reading predefined item %s: %s",
+				    predefined_uri,
+				    error->message);
+		g_error_free (error);
+
+		reason = "user items will not override predefined items that have with errors";
+		should_override = TRUE;
+		goto out;
+	}
+
+	predefined_item = gnome_desktop_item_new_from_string (predefined_uri,
+							      predefined_contents,
+							      predefined_length,
+							      GNOME_DESKTOP_ITEM_LOAD_NO_TRANSLATIONS,
+							      &error);
+
+	if (predefined_item == NULL) {
+		/* can't read desktop file?  let it override the user's stuff, anyway */
+		nautilus_directory_emit_load_error (NAUTILUS_DIRECTORY (desktop), error);
+		nautilus_debug_log (desktop->details->initializing, NAUTILUS_DEBUG_LOG_DOMAIN_DESKTOP_ITEMS,
+				    "Error parsing predefined item %s: %s",
+				    predefined_uri,
+				    error->message);
+		g_error_free (error);
+
+		reason = "user items will not override predefined items that have with errors";
+		should_override = TRUE;
+		goto out;
+	}
+
+	/* Mandatory? */
+
+	if (predefined_desktop_item_is_mandatory (predefined_item)) {
+		reason = "the predefined item is mandatory (include \"X-XDG-Is-Mandatory=false\" to make it non-mandatory)";
+		should_override = TRUE;
+		goto out;
+	}
+
+	/* Not mandatory.  But if the predefined item is newer than the user's, then it overrides the user's. */
+
+	predefined_mtime = nautilus_file_get_mtime (predefined);
+	user_mtime = nautilus_file_get_mtime (user);
+
+	if (predefined_mtime > user_mtime) {
+		reason = "the predefined item is newer than the user item";
+		should_override = TRUE;
+		goto out;
+	}
+
+out:
+
+	if (predefined_item != NULL) {
+		gnome_desktop_item_unref (predefined_item);
+	}
+
+	nautilus_debug_log (desktop->details->initializing, NAUTILUS_DEBUG_LOG_DOMAIN_DESKTOP_ITEMS,
+			    "Predefined item %s %s override user item %s because %s",
+			    predefined_uri,
+			    should_override ? "will" : "will not",
+			    user_uri,
+			    reason);
+
+	g_free (predefined_uri);
+	g_free (user_uri);
+
+	return should_override;
+}
+
+static void
+resolve_overrides_in_file_pair (NautilusDesktopDirectory *desktop, FilePair *pair)
+{
+	if (pair->user_file != NULL && pair->predefined_file != NULL) {
+		pair->predefined_overrides_user = predefined_file_should_override_user_file (desktop, pair->predefined_file, pair->user_file);
+	} else {
+		char *predefined_uri, *user_uri;
+
+		pair->predefined_overrides_user = pair->predefined_file != NULL;
+		g_assert (pair->predefined_overrides_user || pair->user_file != NULL);
+
+		predefined_uri = pair->predefined_file ? nautilus_file_get_uri (pair->predefined_file) : NULL;
+		user_uri = pair->user_file ? nautilus_file_get_uri (pair->user_file) : NULL;
+
+		nautilus_debug_log (desktop->details->initializing, NAUTILUS_DEBUG_LOG_DOMAIN_DESKTOP_ITEMS,
+				    "%s %s is used as it has no counterpart",
+				    pair->predefined_overrides_user ? "Predefined item" : "User item",
+				    predefined_uri ? predefined_uri : user_uri);
+
+		g_free (predefined_uri);
+		g_free (user_uri);
+	}
+}
+
+static void
+find_overriden_files_cb (gpointer key, gpointer value, gpointer data)
+{
+	NautilusDesktopDirectory *desktop;
+	FilePair *pair;
+
+	desktop = NAUTILUS_DESKTOP_DIRECTORY (data);
+	pair = value;
+
+	resolve_overrides_in_file_pair (desktop, pair);
+}
+
+static void
+combine_real_and_predefined_directories (NautilusDesktopDirectory *desktop)
+{
+	g_assert (directories_are_done_loading (desktop));
+
+	if (desktop->details->files_are_combined) {
+		return;
+	}
+
+	desktop->details->files_are_combined = TRUE;
+
+	/* 1. Create pairs for the files */
+
+	create_file_pairs_for_directory (desktop, desktop->details->real_directory, FALSE);
+	create_file_pairs_for_directory (desktop, desktop->details->predefined_items_dir, TRUE);
+
+	/* 2. Figure out which files get overriden */
+
+	g_hash_table_foreach (desktop->details->name_to_pairs_hash, find_overriden_files_cb, desktop);
+
+	desktop->details->initializing = FALSE;
+}
+
+static const char *
+get_debug_dirname (NautilusDesktopDirectory *desktop, NautilusDirectory *directory)
+{
+	if (directory == NAUTILUS_DIRECTORY (desktop)) {
+		return "desktop directory";
+	} else if (directory == desktop->details->real_directory) {
+		return "real directory";
+	} else if (directory == desktop->details->predefined_items_dir) {
+		return "predefined items directory";
+	} else {
+		g_assert_not_reached ();
+		return NULL;
+	}
 }
 
 static void
@@ -153,6 +614,8 @@ directory_ready_callback (NautilusDirectory *directory,
 			  gpointer callback_data)
 {
 	MergedCallback *merged_callback;
+	NautilusDesktopDirectory *desktop;
+	const char *dirname;
 
 	g_assert (NAUTILUS_IS_DIRECTORY (directory));
 	g_assert (callback_data != NULL);
@@ -160,13 +623,13 @@ directory_ready_callback (NautilusDirectory *directory,
 	merged_callback = callback_data;
 	g_assert (g_list_find (merged_callback->non_ready_directories, directory) != NULL);
 
-	/* Update based on this call. */
-	merged_callback->merged_file_list = g_list_concat
-		(merged_callback->merged_file_list,
-		 nautilus_file_list_copy (files));
+	desktop = merged_callback->desktop_dir;
+
+	dirname = get_debug_dirname (desktop, directory);
 
 	/* Check if we are ready. */
 	merged_callback_remove_directory (merged_callback, directory);
+	merged_callback_check_done (merged_callback);
 }
 
 static void
@@ -179,6 +642,12 @@ desktop_call_when_ready (NautilusDirectory *directory,
 	NautilusDesktopDirectory *desktop;
 	MergedCallback search_key, *merged_callback;
 
+	nautilus_debug_log (FALSE, NAUTILUS_DEBUG_LOG_DOMAIN_DEBUG_DESKTOP_ITEMS,
+			    "desktop_call_when_ready (file_attributes=0x%x, wait_for_file_list=%d, callback=%p)",
+			    (int) file_attributes,
+			    (int) wait_for_file_list,
+			    callback);
+
 	desktop = NAUTILUS_DESKTOP_DIRECTORY (directory);
 
 	/* Check to be sure we aren't overwriting. */
@@ -194,36 +663,49 @@ desktop_call_when_ready (NautilusDirectory *directory,
 	merged_callback->desktop_dir = desktop;
 	merged_callback->callback = callback;
 	merged_callback->callback_data = callback_data;
-	merged_callback->wait_for_attributes = file_attributes;
-	merged_callback->wait_for_file_list = wait_for_file_list;
+
+	/* The three non-ready directories are ourselves, the real_directory and the predefined_items_dir */
+
 	merged_callback->non_ready_directories = g_list_prepend
 			(merged_callback->non_ready_directories, directory);
 	merged_callback->non_ready_directories = g_list_prepend
 			(merged_callback->non_ready_directories, desktop->details->real_directory);
 
-
-	merged_callback->merged_file_list = g_list_concat (NULL,
-							   nautilus_file_list_copy (directory->details->file_list));
+	if (desktop->details->predefined_items_dir != NULL) {
+		merged_callback->non_ready_directories = g_list_prepend
+			(merged_callback->non_ready_directories, desktop->details->predefined_items_dir);
+	}
 
 	/* Put it in the hash table. */
 	g_hash_table_insert (desktop->details->callbacks,
 			     merged_callback, merged_callback);
 
-	/* Now tell all the directories about it. */
+	/* Now tell all the directories about it.  We always pass TRUE for
+	 * wait_for_file_list since *we* can't know which files to proxy until
+	 * we have all the ones from the child directories.
+	 */
 	nautilus_directory_call_when_ready
 		(desktop->details->real_directory,
-		 merged_callback->wait_for_attributes,
-		 merged_callback->wait_for_file_list,
+		 file_attributes,
+		 TRUE,
 		 directory_ready_callback, merged_callback);
+
+	if (desktop->details->predefined_items_dir != NULL) {
+		nautilus_directory_call_when_ready
+			(desktop->details->predefined_items_dir,
+			 file_attributes,
+			 TRUE,
+			 directory_ready_callback, merged_callback);
+	}
+
 	nautilus_directory_call_when_ready_internal
 		(directory,
 		 NULL,
-		 merged_callback->wait_for_attributes,
-		 merged_callback->wait_for_file_list,
+		 file_attributes,
+		 FALSE, /* ... but the desktop directory doesn't support wait_for_file_list = TRUE */
 		 directory_ready_callback,
 		 NULL,
 		 merged_callback);
-	
 }
 
 static void
@@ -235,6 +717,10 @@ desktop_cancel_callback (NautilusDirectory *directory,
 	MergedCallback search_key, *merged_callback;
 	GList *node;
 
+	nautilus_debug_log (FALSE, NAUTILUS_DEBUG_LOG_DOMAIN_DEBUG_DESKTOP_ITEMS,
+			    "desktop_cancel_callback (callback=%p)",
+			    callback);
+
 	desktop = NAUTILUS_DESKTOP_DIRECTORY (directory);
 
 	/* Find the entry in the table. */
@@ -267,15 +753,19 @@ merged_monitor_destroy (MergedMonitor *monitor)
 	/* Call through to the real directory remove calls. */
 	nautilus_directory_file_monitor_remove (desktop->details->real_directory, monitor);
 
+	if (desktop->details->predefined_items_dir != NULL) {
+		nautilus_directory_file_monitor_remove (desktop->details->predefined_items_dir, monitor);
+	}
+
 	nautilus_directory_monitor_remove_internal (NAUTILUS_DIRECTORY (desktop), NULL, monitor);
 	
 	g_free (monitor);
 }
 
 static void
-build_merged_callback_list (NautilusDirectory *directory,
-			    GList *file_list,
-			    gpointer callback_data)
+build_file_list_cb (NautilusDirectory *directory,
+		    GList *file_list,
+		    gpointer callback_data)
 {
 	GList **merged_list;
 
@@ -285,6 +775,66 @@ build_merged_callback_list (NautilusDirectory *directory,
 }
 
 static void
+add_file_monitor_and_emit_paired_files (NautilusDesktopDirectory *desktop,
+					NautilusDirectory *directory,
+					MergedMonitor *monitor,
+					gboolean monitor_hidden_files,
+					gboolean monitor_backup_files,
+					NautilusFileAttributes file_attributes,
+					NautilusDirectoryCallback callback,
+					gpointer callback_data)
+{
+	GList *unpaired_files;
+	GList *l;
+	GList *paired_files;
+
+	if (directory == NULL) {
+		return;
+	}
+
+	unpaired_files = NULL;
+
+	nautilus_directory_file_monitor_add (directory,
+					     monitor,
+					     monitor_hidden_files,
+					     monitor_backup_files,
+					     file_attributes,
+					     build_file_list_cb, &unpaired_files);
+
+	/* For each of those files from the directory, pick the ones that are being used in one of our pairs */
+
+	paired_files = NULL;
+
+	for (l = unpaired_files; l; l = l->next) {
+		NautilusFile *file;
+		FilePair *pair;
+
+		file = NAUTILUS_FILE (l->data);
+		pair = g_hash_table_lookup (desktop->details->file_to_pairs_hash, file);
+
+		if (pair == NULL) {
+			continue; /* maybe we haven't been notified yet about that file; we'll handle it later anyway */
+		}
+
+		if (pair_shows_file (pair, file)) {
+			paired_files = g_list_prepend (paired_files, file);
+		}
+	}
+
+	if (callback != NULL) {
+		nautilus_debug_log_with_file_list (FALSE, NAUTILUS_DEBUG_LOG_DOMAIN_DEBUG_DESKTOP_ITEMS, paired_files,
+						   "add_file_monitor_and_emit_paired_files: calling callback %p on directory files",
+						   callback);
+
+		(* callback) (NAUTILUS_DIRECTORY (desktop), paired_files, callback_data);
+	}
+
+	nautilus_file_list_free (unpaired_files);
+	g_list_free (paired_files);
+
+}
+
+static void
 desktop_monitor_add (NautilusDirectory *directory,
 		    gconstpointer client,
 		    gboolean monitor_hidden_files,
@@ -295,7 +845,14 @@ desktop_monitor_add (NautilusDirectory *directory,
 {
 	NautilusDesktopDirectory *desktop;
 	MergedMonitor *monitor;
-	GList *merged_callback_list;
+
+	nautilus_debug_log (FALSE, NAUTILUS_DEBUG_LOG_DOMAIN_DEBUG_DESKTOP_ITEMS,
+			    "desktop_monitor_add (client=%p, monitor_hidden_files=%d, monitor_backup_files=%d, file_attributes=0x%x, callback=%p)",
+			    client,
+			    (int) monitor_hidden_files,
+			    (int) monitor_backup_files,
+			    (int) file_attributes,
+			    callback);
 
 	desktop = NAUTILUS_DESKTOP_DIRECTORY (directory);
 
@@ -315,25 +872,40 @@ desktop_monitor_add (NautilusDirectory *directory,
 	monitor->monitor_backup_files = monitor_backup_files;
 	monitor->monitor_attributes = file_attributes;
 	
-	/* Call through to the real directory add calls. */
-	merged_callback_list = NULL;
-
-	/* Call up to real dir */
-	nautilus_directory_file_monitor_add
-		(desktop->details->real_directory, monitor,
-		 monitor_hidden_files, monitor_backup_files,
-		 file_attributes,
-		 build_merged_callback_list, &merged_callback_list);
-	
-	/* Handle the desktop part */
-	merged_callback_list = g_list_concat (merged_callback_list,
-					      nautilus_file_list_copy (directory->details->file_list));
+	/* Call through to the real directories' add calls. */
+
+	add_file_monitor_and_emit_paired_files (desktop,
+						desktop->details->real_directory,
+						monitor,
+						monitor_hidden_files,
+						monitor_backup_files,
+						file_attributes,
+						callback,
+						callback_data);
+
+	add_file_monitor_and_emit_paired_files (desktop,
+						desktop->details->predefined_items_dir,
+						monitor,
+						monitor_hidden_files,
+						monitor_backup_files,
+						file_attributes,
+						callback,
+						callback_data);
+
+	/* Call the callback on our desktop links */
 
-	
 	if (callback != NULL) {
-		(* callback) (directory, merged_callback_list, callback_data);
+		GList *desktop_link_files;
+
+		desktop_link_files = get_desktop_links (desktop, TRUE);
+
+		nautilus_debug_log_with_file_list (FALSE, NAUTILUS_DEBUG_LOG_DOMAIN_DEBUG_DESKTOP_ITEMS, desktop_link_files,
+						   "desktop_monitor_add: calling callback %p on desktop link files",
+						   callback);
+
+		(* callback) (NAUTILUS_DIRECTORY (desktop), desktop_link_files, callback_data);
+		nautilus_file_list_free (desktop_link_files);
 	}
-	nautilus_file_list_free (merged_callback_list);
 }
 
 static void
@@ -342,6 +914,10 @@ desktop_monitor_remove (NautilusDirectory *directory,
 {
 	NautilusDesktopDirectory *desktop;
 	MergedMonitor *monitor;
+
+	nautilus_debug_log (FALSE, NAUTILUS_DEBUG_LOG_DOMAIN_DEBUG_DESKTOP_ITEMS,
+			    "desktop_monitor_remove (client=%p)",
+			    client);
 	
 	desktop = NAUTILUS_DESKTOP_DIRECTORY (directory);
 
@@ -354,55 +930,143 @@ desktop_monitor_remove (NautilusDirectory *directory,
 }
 
 static void
+free_file_pair (FilePair *pair)
+{
+	g_free (pair->name);
+	pair->name = NULL;
+
+	nautilus_file_unref (pair->user_file);
+	nautilus_file_unref (pair->predefined_file);
+
+	pair->user_file = NULL;
+	pair->predefined_file = NULL;
+
+	g_slice_free (FilePair, pair);
+}
+
+static void
+free_file_pair_cb (gpointer key, gpointer value, gpointer data)
+{
+	FilePair *pair;
+
+	pair = value;
+	g_assert ((char *) key == pair->name);
+
+	free_file_pair (pair);
+}
+
+static void
+destroy_pair_hashes (NautilusDesktopDirectory *desktop)
+{
+	g_hash_table_foreach (desktop->details->name_to_pairs_hash, free_file_pair_cb, NULL);
+	g_hash_table_destroy (desktop->details->name_to_pairs_hash);
+
+	g_hash_table_destroy (desktop->details->file_to_pairs_hash); /* its keys/values were already freed by the call above */
+
+	desktop->details->name_to_pairs_hash = NULL;
+	desktop->details->file_to_pairs_hash = NULL;
+}
+
+static void
+create_pair_hashes (NautilusDesktopDirectory *desktop)
+{
+	g_assert (desktop->details->name_to_pairs_hash == NULL);
+	g_assert (desktop->details->file_to_pairs_hash == NULL);
+
+	desktop->details->name_to_pairs_hash = g_hash_table_new (g_str_hash, g_str_equal);
+	desktop->details->file_to_pairs_hash = g_hash_table_new (g_direct_hash, g_direct_equal);
+}
+
+static void
+invalidate_combined_files (NautilusDesktopDirectory *desktop)
+{
+	destroy_pair_hashes (desktop);
+	create_pair_hashes (desktop);
+
+	desktop->details->files_are_combined = FALSE;
+}
+
+static void
 desktop_force_reload (NautilusDirectory *directory)
 {
 	NautilusDesktopDirectory *desktop;
 
+	nautilus_debug_log (FALSE, NAUTILUS_DEBUG_LOG_DOMAIN_DEBUG_DESKTOP_ITEMS,
+			    "desktop_force_reload(): invalidating files");
+
 	desktop = NAUTILUS_DESKTOP_DIRECTORY (directory);
 
+	invalidate_combined_files (desktop);
+
+	/* Set the pending flags before we start reloading any of the directories */
+
+	desktop->details->real_directory_pending = TRUE;
+
+	if (desktop->details->predefined_items_dir != NULL) {
+		desktop->details->predefined_items_dir_pending = TRUE;
+	}
+
+	/* Reload! */
+
 	nautilus_directory_force_reload (desktop->details->real_directory);
 
-	/* We don't invalidate the files in desktop, since they are always
-	   up to date. (And we don't ever want to mark them invalid.) */
+	if (desktop->details->predefined_items_dir != NULL) {
+		nautilus_directory_force_reload (desktop->details->predefined_items_dir);
+	}
+
+	/* We don't invalidate the "fake" files in desktop (for Home, Computer,
+	   volumes, etc.), since they are always up to date. (And we don't ever
+	   want to mark them invalid.) */
 }
 
 static gboolean
 desktop_are_all_files_seen (NautilusDirectory *directory)
 {
 	NautilusDesktopDirectory *desktop;
+	gboolean result;
 
 	desktop = NAUTILUS_DESKTOP_DIRECTORY (directory);
 
-	if (!nautilus_directory_are_all_files_seen (desktop->details->real_directory)) {
-		return FALSE;
-	}
+	result = desktop->details->files_are_combined;
+
+	nautilus_debug_log (FALSE, NAUTILUS_DEBUG_LOG_DOMAIN_DEBUG_DESKTOP_ITEMS,
+			    "desktop_are_all_files_seen(): %d",
+			    result);
 
-	return TRUE;
+	return result;
 }
 
 static gboolean
 desktop_is_not_empty (NautilusDirectory *directory)
 {
 	NautilusDesktopDirectory *desktop;
+	gboolean result;
 
 	desktop = NAUTILUS_DESKTOP_DIRECTORY (directory);
 
-	if (nautilus_directory_is_not_empty (desktop->details->real_directory)) {
-		return TRUE;
+	if (g_hash_table_size (desktop->details->name_to_pairs_hash) != 0) {
+		result = TRUE;
+	} else {
+		result = directory->details->file_list != NULL; /* this is just for desktop links from NautilusDesktopLinkMonitor */
 	}
 
-	return directory->details->file_list != NULL;
+	nautilus_debug_log (FALSE, NAUTILUS_DEBUG_LOG_DOMAIN_DEBUG_DESKTOP_ITEMS,
+			    "desktop_is_not_empty(): %d",
+			    result);
+
+	return result;
 }
 
 static GList *
 desktop_get_file_list (NautilusDirectory *directory)
 {
-	GList *real_dir_file_list, *desktop_dir_file_list;
-	real_dir_file_list = nautilus_directory_get_file_list
-				(NAUTILUS_DESKTOP_DIRECTORY (directory)->details->real_directory);
-	desktop_dir_file_list = GNOME_CALL_PARENT_WITH_DEFAULT
-				 (NAUTILUS_DIRECTORY_CLASS, get_file_list, (directory), NULL);
-	return g_list_concat (real_dir_file_list, desktop_dir_file_list);
+	GList *result;
+
+	result = get_file_list (NAUTILUS_DESKTOP_DIRECTORY (directory), FALSE);
+	nautilus_debug_log_with_file_list (FALSE, NAUTILUS_DEBUG_LOG_DOMAIN_DEBUG_DESKTOP_ITEMS, result,
+					   "desktop_get_file_list(): returning list of files");
+
+	return result;
 }
 
 NautilusDirectory *
@@ -412,7 +1076,6 @@ nautilus_desktop_directory_get_real_directory (NautilusDesktopDirectory *desktop
 	return desktop->details->real_directory;
 }
 
-
 static void
 desktop_finalize (GObject *object)
 {
@@ -422,39 +1085,431 @@ desktop_finalize (GObject *object)
 
 	nautilus_directory_unref (desktop->details->real_directory);
 
+	if (desktop->details->predefined_items_dir != NULL) {
+		nautilus_directory_unref (desktop->details->predefined_items_dir);
+	}
+
 	g_hash_table_destroy (desktop->details->callbacks);
 	g_hash_table_destroy (desktop->details->monitors);
+
+	destroy_pair_hashes (desktop);
+
 	g_free (desktop->details);
 
 	eel_preferences_remove_callback (NAUTILUS_PREFERENCES_DESKTOP_IS_HOME_DIR,
 					 desktop_directory_changed_callback,
 					 desktop);
+	eel_preferences_remove_callback (NAUTILUS_PREFERENCES_DESKTOP_PREDEFINED_ITEMS_DIR,
+					 predefined_items_dir_changed_callback,
+					 desktop);
 	
 	G_OBJECT_CLASS (parent_class)->finalize (object);
 }
 
 static void
-done_loading_callback (NautilusDirectory *real_directory,
-		       NautilusDesktopDirectory *desktop)
+load_error_callback (NautilusDirectory *directory, GError *error, NautilusDesktopDirectory *desktop)
+{
+	nautilus_debug_log (FALSE, NAUTILUS_DEBUG_LOG_DOMAIN_DESKTOP_ITEMS,
+			    "Error while loading %s: %s",
+			    get_debug_dirname (desktop, directory),
+			    error->message);
+
+	nautilus_directory_emit_load_error (NAUTILUS_DIRECTORY (desktop), error);
+}
+
+static gboolean
+directories_are_done_loading (NautilusDesktopDirectory *desktop)
 {
-     nautilus_directory_emit_done_loading (NAUTILUS_DIRECTORY (desktop));
+	gboolean real_is_done;
+	gboolean predefined_is_done;
+
+	real_is_done = !desktop->details->real_directory_pending;
+
+	predefined_is_done = (desktop->details->predefined_items_dir == NULL || !desktop->details->predefined_items_dir_pending);
+
+	return real_is_done && predefined_is_done;
 }
 
+static void
+emit_pending_callback_cb (gpointer key, gpointer value, gpointer data)
+{
+	MergedCallback *merged_callback;
+
+	merged_callback = key;
+	merged_callback_check_done (merged_callback);
+}
 
 static void
-forward_files_added_cover (NautilusDirectory *real_directory,
+emit_pending_callbacks (NautilusDesktopDirectory *desktop)
+{
+	g_hash_table_foreach (desktop->details->callbacks, emit_pending_callback_cb, desktop);
+}
+
+static void
+done_loading_callback (NautilusDirectory *directory,
+		       NautilusDesktopDirectory *desktop)
+{
+	if (directory == desktop->details->real_directory) {
+		desktop->details->real_directory_pending = FALSE;
+	} else if (directory == desktop->details->predefined_items_dir) {
+		desktop->details->predefined_items_dir_pending = FALSE;
+	} else {
+		g_assert_not_reached ();
+	}
+
+	if (directories_are_done_loading (desktop)) {
+		nautilus_debug_log (FALSE, NAUTILUS_DEBUG_LOG_DOMAIN_DEBUG_DESKTOP_ITEMS,
+				    "done_loading_callback(): %s and all directories are done; will combine files, emit callbacks, and emit done_loading",
+				    get_debug_dirname (desktop, directory));
+
+		combine_real_and_predefined_directories (desktop);
+		emit_pending_callbacks (desktop);
+		nautilus_directory_emit_done_loading (NAUTILUS_DIRECTORY (desktop));
+	} else {
+		nautilus_debug_log (FALSE, NAUTILUS_DEBUG_LOG_DOMAIN_DEBUG_DESKTOP_ITEMS,
+				    "done_loading_callback(): %s is done loading, but not all dirs are ready yet",
+				    get_debug_dirname (desktop, directory));
+	}
+}
+
+static void
+forward_files_added_cover (NautilusDirectory *directory,
 			   GList *files,
 			   gpointer callback_data)
 {
-	nautilus_directory_emit_files_added (NAUTILUS_DIRECTORY (callback_data), files);
+	NautilusDesktopDirectory *desktop;
+	gboolean is_predefined_dir;
+	GList *l;
+	GList *files_removed;
+	GList *files_added;
+
+	desktop = NAUTILUS_DESKTOP_DIRECTORY (callback_data);
+
+	nautilus_debug_log_with_file_list (FALSE, NAUTILUS_DEBUG_LOG_DOMAIN_DEBUG_DESKTOP_ITEMS, files,
+					   "forward_files_added_cover(): files got added to %s. files_are_combined=%d",
+					   get_debug_dirname (desktop, directory),
+					   desktop->details->files_are_combined);
+
+	if (!desktop->details->files_are_combined) {
+		return;
+	}
+
+	if (directory == desktop->details->real_directory) {
+		is_predefined_dir = FALSE;
+	} else if (directory == desktop->details->predefined_items_dir) {
+		is_predefined_dir = TRUE;
+	} else {
+		g_assert_not_reached ();
+	}
+
+	files_removed = NULL;
+	files_added = NULL;
+
+	for (l = files; l; l = l->next) {
+		NautilusFile *file;
+		FilePair *pair;
+		gboolean is_new_pair;
+		gboolean predefined_was_being_used;
+		char *uri;
+
+		file = NAUTILUS_FILE (l->data);
+
+		uri = nautilus_file_get_uri (file);
+
+		nautilus_debug_log (FALSE, NAUTILUS_DEBUG_LOG_DOMAIN_DESKTOP_ITEMS,
+				    "File added to %s: %s -- determining if it gets overriden",
+				    is_predefined_dir ? "predefined items" : "user items",
+				    uri);
+
+		pair = create_file_pair (desktop, NAUTILUS_FILE (l->data), is_predefined_dir, &is_new_pair);
+		log_pair (pair, is_new_pair);
+		predefined_was_being_used = pair->predefined_overrides_user;
+
+		resolve_overrides_in_file_pair (desktop, pair);
+
+		if (is_new_pair) {
+			nautilus_debug_log (FALSE, NAUTILUS_DEBUG_LOG_DOMAIN_DESKTOP_ITEMS,
+					    "%s will appear in the user's desktop (it has no %s counterpart)",
+					    uri,
+					    is_predefined_dir ? "user" : "predefined");
+
+			files_added = g_list_prepend (files_added, file);
+		} else {
+			gboolean log_replacement;
+
+			log_replacement = FALSE;
+			if (predefined_was_being_used) {
+				g_assert (!is_predefined_dir && file == pair->user_file);
+
+				if (!pair->predefined_overrides_user) {
+					log_replacement = TRUE;
+					files_removed = g_list_prepend (files_removed, pair->predefined_file);
+					files_added = g_list_prepend (files_added, pair->user_file);
+				}
+			} else {
+				g_assert (is_predefined_dir && file == pair->predefined_file);
+
+				if (pair->predefined_overrides_user) {
+					log_replacement = TRUE;
+					files_removed = g_list_prepend (files_removed, pair->user_file);
+					files_added = g_list_prepend (files_added, pair->predefined_file);
+				}
+			}
+
+			if (log_replacement) {
+				nautilus_debug_log (FALSE, NAUTILUS_DEBUG_LOG_DOMAIN_DESKTOP_ITEMS,
+						    "%s replaces what was in the user's desktop",
+						    uri);
+			}
+		}
+
+		g_free (uri);
+	}
+
+	nautilus_debug_log_with_file_list (FALSE, NAUTILUS_DEBUG_LOG_DOMAIN_DEBUG_DESKTOP_ITEMS, files_removed,
+					   "forward_files_added_cover: emitting removed files");
+	nautilus_debug_log_with_file_list (FALSE, NAUTILUS_DEBUG_LOG_DOMAIN_DEBUG_DESKTOP_ITEMS, files_added,
+					   "forward_files_added_cover: emitting added files");
+
+	nautilus_directory_emit_files_changed (NAUTILUS_DIRECTORY (desktop), files_removed);
+	nautilus_directory_emit_files_added (NAUTILUS_DIRECTORY (desktop), files_added);
+
+	g_list_free (files_removed);
+	g_list_free (files_added);
 }
 
 static void
-forward_files_changed_cover (NautilusDirectory *real_directory,
+forward_files_changed_cover (NautilusDirectory *directory,
 			     GList *files,
 			     gpointer callback_data)
 {
-	nautilus_directory_emit_files_changed (NAUTILUS_DIRECTORY (callback_data), files);
+	NautilusDesktopDirectory *desktop;
+	gboolean is_predefined_dir;
+	GList *l;
+	GList *files_changed;
+	GList *files_added;
+
+	desktop = NAUTILUS_DESKTOP_DIRECTORY (callback_data);
+
+	nautilus_debug_log_with_file_list (FALSE, NAUTILUS_DEBUG_LOG_DOMAIN_DEBUG_DESKTOP_ITEMS, files,
+					   "forward_files_changed_cover(): files got changed in %s.  files_are_combined=%d",
+					   get_debug_dirname (desktop, directory),
+					   desktop->details->files_are_combined);
+
+	if (!desktop->details->files_are_combined) {
+		return;
+	}
+
+	if (directory == desktop->details->real_directory) {
+		is_predefined_dir = FALSE;
+	} else if (directory == desktop->details->predefined_items_dir) {
+		is_predefined_dir = TRUE;
+	} else {
+		g_assert_not_reached ();
+	}
+
+	files_changed = NULL;
+	files_added = NULL;
+
+	for (l = files; l; l = l->next) {
+		NautilusFile *file;
+		FilePair *pair;
+		char *uri;
+
+		file = NAUTILUS_FILE (l->data);
+		uri = nautilus_file_get_uri (file);
+
+		nautilus_debug_log (FALSE, NAUTILUS_DEBUG_LOG_DOMAIN_DESKTOP_ITEMS,
+				    "File changed in %s: %s -- determining if it gets overriden",
+				    is_predefined_dir ? "predefined items" : "user items",
+				    uri);
+
+		pair = g_hash_table_lookup (desktop->details->file_to_pairs_hash, file);
+
+		if (pair == NULL) {
+			GList node;
+
+			/* Huh, we didn't know about that file?  Act as if it had been added. */
+
+			node.data = file;
+			node.prev = NULL;
+			node.next = NULL;
+
+			if (nautilus_directory_contains_file (directory, file)) {
+				nautilus_debug_log (FALSE, NAUTILUS_DEBUG_LOG_DOMAIN_DESKTOP_ITEMS,
+						    "Trying to add %s as a new file",
+						    uri);
+				forward_files_added_cover (directory, &node, callback_data);
+			} else {
+				nautilus_debug_log (FALSE, NAUTILUS_DEBUG_LOG_DOMAIN_DESKTOP_ITEMS,
+						    "Ignoring %s - it no longer exists in its directory",
+						    uri);
+			}
+		} else {
+			gboolean predefined_was_being_used;
+
+			predefined_was_being_used = pair->predefined_overrides_user;
+
+			if (nautilus_directory_contains_file (directory, file)) {
+				char *name;
+				gboolean same_name;
+
+				name = nautilus_file_get_name (file);
+				same_name = strcmp (name, pair->name) == 0;
+				g_free (name);
+
+				if (same_name) {
+					/* The file still belongs within its pair */
+					resolve_overrides_in_file_pair (desktop, pair);
+
+					if (predefined_was_being_used == pair->predefined_overrides_user) {
+						if (pair_shows_file (pair, file)) {
+							nautilus_debug_log (FALSE, NAUTILUS_DEBUG_LOG_DOMAIN_DEBUG_DESKTOP_ITEMS,
+									    "%s is still shown; will emit changed for it",
+									    uri);
+							files_changed = g_list_prepend (files_changed, file);
+						} else {
+							/* Otherwise we weren't exposing the file anyway, so the caller
+							 * doesn't need to know that it changed.
+							 */
+							nautilus_debug_log (FALSE, NAUTILUS_DEBUG_LOG_DOMAIN_DEBUG_DESKTOP_ITEMS,
+									    "%s changed but wasn't being shown anyway; will ignore it",
+									    uri);
+						}
+					} else {
+						NautilusFile *changed;
+						NautilusFile *added;
+						char *added_uri;
+
+						if (predefined_was_being_used) {
+							changed = pair->user_file;		/* "got removed from our view" */
+							added = pair->predefined_file;
+						} else {
+							changed = pair->predefined_file;	/* as above */
+							added = pair->user_file;
+						}
+
+						added_uri = nautilus_file_get_uri (added);
+						nautilus_debug_log (FALSE, NAUTILUS_DEBUG_LOG_DOMAIN_DEBUG_DESKTOP_ITEMS,
+								    "%s is no longer shown; will emit it as changed and emit its pair %s as added",
+								    uri,
+								    added_uri);
+						g_free (added_uri);
+
+						files_changed = g_list_prepend (files_changed, changed);
+						files_added = g_list_prepend (files_added, added);
+					}
+				} else {
+					GList node;
+					NautilusFile *remaining_file;
+
+					nautilus_debug_log (FALSE, NAUTILUS_DEBUG_LOG_DOMAIN_DEBUG_DESKTOP_ITEMS,
+							    "%s changed name from %s; will emit changed for it, and call files_added to move it to a new pair",
+							    uri,
+							    pair->name);
+
+					/* The file no longer belongs in this pair */
+
+					g_hash_table_remove (desktop->details->file_to_pairs_hash, file);
+
+					if (file == pair->predefined_file) {
+						pair->predefined_file = NULL;
+						pair->predefined_overrides_user = FALSE;
+						remaining_file = pair->user_file;
+					} else {
+						g_assert (file == pair->user_file);
+						pair->user_file = NULL;
+						pair->predefined_overrides_user = TRUE;
+						remaining_file = pair->predefined_file;
+					}
+
+					if (remaining_file == NULL) {
+						g_hash_table_remove (desktop->details->name_to_pairs_hash, pair->name);
+						free_file_pair (pair);
+					} else {
+						files_added = g_list_prepend (files_added, remaining_file);
+					}
+
+					node.data = file;
+					node.prev = NULL;
+					node.next = NULL;
+					nautilus_directory_emit_files_changed (NAUTILUS_DIRECTORY (desktop), &node);
+
+					/* Re-insert the file in a new pair */
+
+					node.data = file;
+					node.prev = NULL;
+					node.next = NULL;
+					forward_files_added_cover (directory, &node, callback_data);
+
+					nautilus_file_unref (file); /* as it was referenced in the old pair */
+				}
+			} else {
+				NautilusFile *remaining_file;
+
+				nautilus_debug_log (FALSE, NAUTILUS_DEBUG_LOG_DOMAIN_DEBUG_DESKTOP_ITEMS,
+						    "%s no longer exists in the %s directory; will emit changed for it",
+						    uri,
+						    get_debug_dirname (desktop, directory));
+
+				/* The file no longer exists in its directory
+				 * (it got deleted or something), so we'll
+				 * remove it from our pair.
+				 */
+
+				files_changed = g_list_prepend (files_changed, file);
+				g_hash_table_remove (desktop->details->file_to_pairs_hash, file);
+
+				if (file == pair->predefined_file) {
+					pair->predefined_file = NULL;
+					pair->predefined_overrides_user = FALSE;
+					remaining_file = pair->user_file;
+				} else {
+					g_assert (file == pair->user_file);
+					pair->user_file = NULL;
+					pair->predefined_overrides_user = TRUE;
+					remaining_file = pair->predefined_file;
+				}
+
+				nautilus_file_unref (file);
+
+				if (remaining_file == NULL) {
+					g_hash_table_remove (desktop->details->name_to_pairs_hash, pair->name);
+					free_file_pair (pair);
+				}
+			}
+		}
+
+		g_free (uri);
+	}
+
+	nautilus_debug_log_with_file_list (FALSE, NAUTILUS_DEBUG_LOG_DOMAIN_DEBUG_DESKTOP_ITEMS, files_changed,
+					   "forward_files_changed_cover: emitting changed files");
+	nautilus_debug_log_with_file_list (FALSE, NAUTILUS_DEBUG_LOG_DOMAIN_DEBUG_DESKTOP_ITEMS, files_added,
+					   "forward_files_changed_cover: emitting added files");
+
+	nautilus_directory_emit_files_changed (NAUTILUS_DIRECTORY (desktop), files_changed);
+	nautilus_directory_emit_files_added (NAUTILUS_DIRECTORY (desktop), files_added);
+
+	g_list_free (files_changed);
+	g_list_free (files_added);
+}
+
+static void
+discard_directory (NautilusDesktopDirectory *desktop, NautilusDirectory *dir)
+{
+	if (dir == NULL) {
+		return;
+	}
+
+	g_hash_table_foreach_remove (desktop->details->callbacks, (GHRFunc) gtk_true, NULL);
+	g_hash_table_foreach_remove (desktop->details->monitors, (GHRFunc) gtk_true, NULL);
+
+	g_signal_handlers_disconnect_by_func (dir, done_loading_callback, desktop);
+	g_signal_handlers_disconnect_by_func (dir, forward_files_added_cover, desktop);
+	g_signal_handlers_disconnect_by_func (dir, forward_files_changed_cover, desktop);
+
+	nautilus_directory_unref (dir);
 }
 
 static void
@@ -464,17 +1519,10 @@ update_desktop_directory (NautilusDesktopDirectory *desktop)
 	char *desktop_uri;
 	NautilusDirectory *real_directory;
 
-	real_directory = desktop->details->real_directory;
-	if (real_directory != NULL) {
-		g_hash_table_foreach_remove (desktop->details->callbacks, (GHRFunc) gtk_true, NULL);
-		g_hash_table_foreach_remove (desktop->details->monitors, (GHRFunc) gtk_true, NULL);
+	invalidate_combined_files (desktop);
 
-		g_signal_handlers_disconnect_by_func (real_directory, done_loading_callback, desktop);
-		g_signal_handlers_disconnect_by_func (real_directory, forward_files_added_cover, desktop);
-		g_signal_handlers_disconnect_by_func (real_directory, forward_files_changed_cover, desktop);
-
-		nautilus_directory_unref (real_directory);
-	}
+	discard_directory (desktop, desktop->details->real_directory);
+	desktop->details->real_directory = NULL;
 
 	desktop_path = nautilus_get_desktop_directory ();
 	desktop_uri = g_filename_to_uri (desktop_path, NULL, NULL);
@@ -482,6 +1530,8 @@ update_desktop_directory (NautilusDesktopDirectory *desktop)
 	g_free (desktop_uri);
 	g_free (desktop_path);
 
+	g_signal_connect_object (real_directory, "load_error",
+				 G_CALLBACK (load_error_callback), desktop, 0);
 	g_signal_connect_object (real_directory, "done_loading",
 				 G_CALLBACK (done_loading_callback), desktop, 0);
 	g_signal_connect_object (real_directory, "files_added",
@@ -490,6 +1540,7 @@ update_desktop_directory (NautilusDesktopDirectory *desktop)
 				 G_CALLBACK (forward_files_changed_cover), desktop, 0);
 
 	desktop->details->real_directory = real_directory;
+	desktop->details->real_directory_pending = TRUE;
 }
 
 static void
@@ -500,8 +1551,64 @@ desktop_directory_changed_callback (gpointer data)
 }
 
 static void
+update_predefined_items_dir (NautilusDesktopDirectory *desktop)
+{
+	NautilusDirectory *predefined_items_dir;
+	char *dirname;
+	char *uri;
+
+	invalidate_combined_files (desktop);
+
+	discard_directory (desktop, desktop->details->predefined_items_dir);
+	desktop->details->predefined_items_dir = NULL;
+
+	dirname = eel_preferences_get (NAUTILUS_PREFERENCES_DESKTOP_PREDEFINED_ITEMS_DIR);
+	if (dirname == NULL || *dirname == 0) {
+		nautilus_debug_log (FALSE, NAUTILUS_DEBUG_LOG_DOMAIN_DESKTOP_ITEMS,
+				    "The predefined_items_dir key is not set; will not have predefined desktop items");
+		g_free (dirname);
+		return;
+	}
+
+	nautilus_debug_log (desktop->details->initializing, NAUTILUS_DEBUG_LOG_DOMAIN_DESKTOP_ITEMS,
+			    "Using predefined_items_dir = %s", dirname);
+
+	uri = g_filename_to_uri (dirname, NULL, NULL);
+	predefined_items_dir = nautilus_directory_get_by_uri (uri);
+	g_free (uri);
+	g_free (dirname);
+
+	g_signal_connect_object (predefined_items_dir, "load_error",
+				 G_CALLBACK (load_error_callback), desktop, 0);
+	g_signal_connect_object (predefined_items_dir, "done_loading",
+				 G_CALLBACK (done_loading_callback), desktop, 0);
+	g_signal_connect_object (predefined_items_dir, "files_added",
+				 G_CALLBACK (forward_files_added_cover), desktop, 0);
+	g_signal_connect_object (predefined_items_dir, "files_changed",
+				 G_CALLBACK (forward_files_changed_cover), desktop, 0);
+
+	desktop->details->predefined_items_dir = predefined_items_dir;
+	desktop->details->predefined_items_dir_pending = TRUE;
+}
+
+static void
+predefined_items_dir_changed_callback (gpointer data)
+{
+	NautilusDesktopDirectory *desktop = NAUTILUS_DESKTOP_DIRECTORY (data);
+
+	nautilus_debug_log (FALSE, NAUTILUS_DEBUG_LOG_DOMAIN_DESKTOP_ITEMS,
+			    "GConf key for the path for predefined desktop items changed; refreshing...");
+
+	update_predefined_items_dir (desktop);
+	nautilus_directory_force_reload (NAUTILUS_DIRECTORY (desktop));
+}
+
+static void
 nautilus_desktop_directory_instance_init (NautilusDesktopDirectory *desktop)
 {
+	nautilus_debug_log (TRUE, NAUTILUS_DEBUG_LOG_DOMAIN_DESKTOP_ITEMS,
+			    "Creating the NautilusDesktopDirectory");
+
 	desktop->details = g_new0 (NautilusDesktopDirectoryDetails, 1);
 
 	desktop->details->callbacks = g_hash_table_new_full
@@ -510,11 +1617,19 @@ nautilus_desktop_directory_instance_init (NautilusDesktopDirectory *desktop)
 	desktop->details->monitors = g_hash_table_new_full (NULL, NULL,
 							    NULL, (GDestroyNotify)merged_monitor_destroy);
 
+	create_pair_hashes (desktop);
+
+	desktop->details->initializing = TRUE;
+
 	update_desktop_directory (NAUTILUS_DESKTOP_DIRECTORY (desktop));
+	update_predefined_items_dir (desktop);
 
 	eel_preferences_add_callback (NAUTILUS_PREFERENCES_DESKTOP_IS_HOME_DIR,
 				      desktop_directory_changed_callback,
 				      desktop);
+	eel_preferences_add_callback (NAUTILUS_PREFERENCES_DESKTOP_PREDEFINED_ITEMS_DIR,
+				      predefined_items_dir_changed_callback,
+				      desktop);
 }
 
 static void
diff --git a/libnautilus-private/nautilus-desktop-icon-file.c b/libnautilus-private/nautilus-desktop-icon-file.c
index 3802dd9..120df10 100644
--- a/libnautilus-private/nautilus-desktop-icon-file.c
+++ b/libnautilus-private/nautilus-desktop-icon-file.c
@@ -26,6 +26,7 @@
 #include <config.h>
 #include "nautilus-desktop-icon-file.h"
 
+#include "nautilus-debug-log.h"
 #include "nautilus-directory-notify.h"
 #include "nautilus-directory-private.h"
 #include "nautilus-file-attributes.h"
@@ -291,6 +292,9 @@ nautilus_desktop_icon_file_new (NautilusDesktopLink *link)
 	list.prev = NULL;
 	nautilus_directory_emit_files_added (directory, &list);
 
+	nautilus_debug_log_with_file_list (FALSE, NAUTILUS_DEBUG_LOG_DOMAIN_DEBUG_DESKTOP_ITEMS, &list,
+					   "Created desktop icon file and notified directory:");
+
 	return icon_file;
 }
 
diff --git a/libnautilus-private/nautilus-desktop-link-monitor.c b/libnautilus-private/nautilus-desktop-link-monitor.c
index 9abdd64..976ccd8 100644
--- a/libnautilus-private/nautilus-desktop-link-monitor.c
+++ b/libnautilus-private/nautilus-desktop-link-monitor.c
@@ -23,6 +23,7 @@
 */
 
 #include <config.h>
+#include "nautilus-debug-log.h"
 #include "nautilus-desktop-link-monitor.h"
 #include "nautilus-desktop-link.h"
 #include "nautilus-desktop-icon-file.h"
@@ -356,6 +357,9 @@ nautilus_desktop_link_monitor_init (gpointer object, gpointer klass)
 	GList *l, *mounts;
 	GMount *mount;
 
+	nautilus_debug_log (FALSE, NAUTILUS_DEBUG_LOG_DOMAIN_DESKTOP_ITEMS,
+			    "Initializing desktop link monitor with all its links");
+
 	monitor = NAUTILUS_DESKTOP_LINK_MONITOR (object);
 
 	the_link_monitor = monitor;
diff --git a/libnautilus-private/nautilus-directory-async.c b/libnautilus-private/nautilus-directory-async.c
index cbe0419..ba67a75 100644
--- a/libnautilus-private/nautilus-directory-async.c
+++ b/libnautilus-private/nautilus-directory-async.c
@@ -24,6 +24,7 @@
 
 #include <config.h>
 
+#include "nautilus-debug-log.h"
 #include "nautilus-directory-metafile.h"
 #include "nautilus-directory-notify.h"
 #include "nautilus-directory-private.h"
@@ -1039,6 +1040,15 @@ directory_load_done (NautilusDirectory *directory,
 		     GError *error)
 {
 	GList *node;
+	char *uri;
+
+	uri = nautilus_directory_get_uri (directory);
+	nautilus_debug_log (FALSE, NAUTILUS_DEBUG_LOG_DOMAIN_ASYNC,
+			    "Directory %p (%s): directory_load_done: %s",
+			    directory,
+			    uri,
+			    error ? error->message : "success");
+	g_free (uri);
 
 	directory->details->directory_loaded = TRUE;
 	directory->details->directory_loaded_sent_notification = FALSE;
diff --git a/libnautilus-private/nautilus-global-preferences.h b/libnautilus-private/nautilus-global-preferences.h
index e3de760..d414bed 100644
--- a/libnautilus-private/nautilus-global-preferences.h
+++ b/libnautilus-private/nautilus-global-preferences.h
@@ -214,6 +214,7 @@ typedef enum
 #define NAUTILUS_PREFERENCES_DESKTOP_VOLUMES_VISIBLE	   "desktop/volumes_visible"
 #define NAUTILUS_PREFERENCES_DESKTOP_NETWORK_VISIBLE       "desktop/network_icon_visible"
 #define NAUTILUS_PREFERENCES_DESKTOP_NETWORK_NAME          "desktop/network_icon_name"
+#define NAUTILUS_PREFERENCES_DESKTOP_PREDEFINED_ITEMS_DIR  "desktop/predefined_items_dir"
 
 void nautilus_global_preferences_init                      (void);
 char *nautilus_global_preferences_get_default_folder_viewer_preference_as_iid (void);
diff --git a/src/nautilus-desktop-window.c b/src/nautilus-desktop-window.c
index 6871bde..ea0fc61 100644
--- a/src/nautilus-desktop-window.c
+++ b/src/nautilus-desktop-window.c
@@ -33,6 +33,7 @@
 #include <eel/eel-gtk-macros.h>
 #include <eel/eel-vfs-extensions.h>
 #include <libgnome/gnome-macros.h>
+#include <libnautilus-private/nautilus-debug-log.h>
 #include <libnautilus-private/nautilus-file-utilities.h>
 #include <libnautilus-private/nautilus-icon-names.h>
 #include <gio/gio.h>
@@ -118,6 +119,9 @@ nautilus_desktop_window_new (NautilusApplication *application,
 	width_request = gdk_screen_get_width (screen);
 	height_request = gdk_screen_get_height (screen);
 
+	nautilus_debug_log (TRUE, NAUTILUS_DEBUG_LOG_DOMAIN_DESKTOP_ITEMS,
+			    "Initializing desktop window with size %dx%d", width_request, height_request);
+
 	window = NAUTILUS_DESKTOP_WINDOW
 		(gtk_widget_new (nautilus_desktop_window_get_type(),
 				 "app", application,