Process some GFileMonitor events

So far, it's rather crude.

6 files changed, 463 insertions, 162 deletions

diff --git a/fiv-browser.c b/fiv-browser.c
index 01ff8f0..8c79ca6 100644
--- a/fiv-browser.c
+++ b/fiv-browser.c
@@ -32,6 +32,7 @@
 #include "fiv-collection.h"
 #include "fiv-context-menu.h"
 #include "fiv-io.h"
+#include "fiv-io-model.h"
 #include "fiv-thumbnail.h"
 
 // --- Widget ------------------------------------------------------------------
@@ -78,7 +79,7 @@ struct _FivBrowser {
 	gboolean show_labels;               ///< Show labels underneath items
 
 	FivIoModel *model;                  ///< Filesystem model
-	GArray *entries;                    ///< []Entry
+	GPtrArray *entries;                 ///< []*Entry
 	GArray *layouted_rows;              ///< []Row
 	const Entry *selected;              ///< Selected entry or NULL
 
@@ -112,14 +113,25 @@ struct entry {
 	FivIoModelEntry *e;                 ///< Reference to model entry
 	cairo_surface_t *thumbnail;         ///< Prescaled thumbnail
 	GIcon *icon;                        ///< If no thumbnail, use this icon
+
+	gboolean removed;                   ///< Model announced removal
 };
 
+static Entry *
+entry_new(FivIoModelEntry *e)
+{
+	Entry *self = g_slice_alloc0(sizeof *self);
+	self->e = e;
+	return self;
+}
+
 static void
-entry_free(Entry *self)
+entry_destroy(Entry *self)
 {
 	fiv_io_model_entry_unref(self->e);
 	g_clear_pointer(&self->thumbnail, cairo_surface_destroy);
 	g_clear_object(&self->icon);
+	g_slice_free1(sizeof *self, self);
 }
 
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@@ -202,7 +214,7 @@ relayout(FivBrowser *self, int width)
 	GArray *items = g_array_new(TRUE, TRUE, sizeof(Item));
 	int x = 0, y = padding.top;
 	for (guint i = 0; i < self->entries->len; i++) {
-		const Entry *entry = &g_array_index(self->entries, Entry, i);
+		const Entry *entry = self->entries->pdata[i];
 		if (!entry->thumbnail)
 			continue;
 
@@ -414,6 +426,15 @@ draw_row(FivBrowser *self, cairo_t *cr, const Row *row)
 			// the whole rectangle with the selection color.
 		}
 
+		// TODO(p): Come up with a better rendition.
+		if (item->entry->removed) {
+			cairo_move_to(cr, 0, border.top + extents.height + border.bottom);
+			cairo_line_to(cr, border.left + extents.width + border.right, 0);
+			cairo_set_source_rgb(cr, 0.5, 0.5, 0.5);
+			cairo_set_line_width(cr, 5);
+			cairo_stroke(cr);
+		}
+
 		if (self->show_labels) {
 			gtk_style_context_save(style);
 			gtk_style_context_add_class(style, "label");
@@ -522,14 +543,9 @@ entry_set_surface_user_data(const Entry *self)
 		NULL);
 }
 
-static void
-entry_add_thumbnail(gpointer data, gpointer user_data)
+static cairo_surface_t *
+entry_lookup_thumbnail(Entry *self, FivBrowser *browser)
 {
-	Entry *self = data;
-	g_clear_object(&self->icon);
-	g_clear_pointer(&self->thumbnail, cairo_surface_destroy);
-
-	FivBrowser *browser = FIV_BROWSER(user_data);
 	cairo_surface_t *cached =
 		g_hash_table_lookup(browser->thumbnail_cache, self->e->uri);
 	if (cached &&
@@ -537,18 +553,39 @@ entry_add_thumbnail(gpointer data, gpointer user_data)
 			&fiv_browser_key_mtime_msec) == (intptr_t) self->e->mtime_msec &&
 		(uintptr_t) cairo_surface_get_user_data(cached,
 			&fiv_browser_key_filesize) == (uintptr_t) self->e->filesize) {
-		self->thumbnail = cairo_surface_reference(cached);
 		// TODO(p): If this hit is low-quality, see if a high-quality thumbnail
 		// hasn't been produced without our knowledge (avoid launching a minion
 		// unnecessarily; we might also shift the concern there).
-	} else {
-		cairo_surface_t *found = fiv_thumbnail_lookup(
-			entry_system_wide_uri(self), self->e->mtime_msec, self->e->filesize,
-			browser->item_size);
-		self->thumbnail = rescale_thumbnail(found, browser->item_height);
+		return cairo_surface_reference(cached);
+	}
+
+	cairo_surface_t *found = fiv_thumbnail_lookup(
+		entry_system_wide_uri(self), self->e->mtime_msec, self->e->filesize,
+		browser->item_size);
+	return rescale_thumbnail(found, browser->item_height);
+}
+
+static void
+entry_add_thumbnail(gpointer data, gpointer user_data)
+{
+	Entry *self = data;
+	FivBrowser *browser = FIV_BROWSER(user_data);
+	if (self->removed) {
+		// Keep whatever size of thumbnail we had at the time up until reload.
+		// g_file_query_info() fails for removed files, so keep the icon, too.
+		if (self->icon) {
+			g_clear_pointer(&self->thumbnail, cairo_surface_destroy);
+		} else {
+			self->thumbnail =
+				rescale_thumbnail(self->thumbnail, browser->item_height);
+		}
+		return;
 	}
 
-	if (self->thumbnail) {
+	g_clear_object(&self->icon);
+	g_clear_pointer(&self->thumbnail, cairo_surface_destroy);
+
+	if ((self->thumbnail = entry_lookup_thumbnail(self, browser))) {
 		// Yes, this is a pointless action in case it's been found in the cache.
 		entry_set_surface_user_data(self);
 		return;
@@ -624,15 +661,15 @@ reload_thumbnails(FivBrowser *self)
 	GThreadPool *pool = g_thread_pool_new(
 		entry_add_thumbnail, self, g_get_num_processors(), FALSE, NULL);
 	for (guint i = 0; i < self->entries->len; i++)
-		g_thread_pool_push(pool, &g_array_index(self->entries, Entry, i), NULL);
+		g_thread_pool_push(pool, self->entries->pdata[i], NULL);
 	g_thread_pool_free(pool, FALSE, TRUE);
 
 	// Once a URI disappears from the model, its thumbnail is forgotten.
 	g_hash_table_remove_all(self->thumbnail_cache);
 
 	for (guint i = 0; i < self->entries->len; i++) {
-		Entry *entry = &g_array_index(self->entries, Entry, i);
-		if (entry->thumbnail) {
+		Entry *entry = self->entries->pdata[i];
+		if (!entry->removed && entry->thumbnail) {
 			g_hash_table_insert(self->thumbnail_cache, g_strdup(entry->e->uri),
 				cairo_surface_reference(entry->thumbnail));
 		}
@@ -790,7 +827,10 @@ thumbnailers_start(FivBrowser *self)
 
 	GQueue lq = G_QUEUE_INIT;
 	for (guint i = 0; i < self->entries->len; i++) {
-		Entry *entry = &g_array_index(self->entries, Entry, i);
+		Entry *entry = self->entries->pdata[i];
+		if (entry->removed)
+			continue;
+
 		if (entry->icon)
 			g_queue_push_tail(&self->thumbnailers_queue, entry);
 		else if (cairo_surface_get_user_data(
@@ -868,7 +908,7 @@ fiv_browser_finalize(GObject *gobject)
 {
 	FivBrowser *self = FIV_BROWSER(gobject);
 	thumbnailers_abort(self);
-	g_array_free(self->entries, TRUE);
+	g_ptr_array_free(self->entries, TRUE);
 	g_array_free(self->layouted_rows, TRUE);
 	if (self->model) {
 		g_signal_handlers_disconnect_by_data(self->model, self);
@@ -1774,8 +1814,8 @@ fiv_browser_init(FivBrowser *self)
 	gtk_widget_set_can_focus(GTK_WIDGET(self), TRUE);
 	gtk_widget_set_has_tooltip(GTK_WIDGET(self), TRUE);
 
-	self->entries = g_array_new(FALSE, TRUE, sizeof(Entry));
-	g_array_set_clear_func(self->entries, (GDestroyNotify) entry_free);
+	self->entries =
+		g_ptr_array_new_with_free_func((GDestroyNotify) entry_destroy);
 	self->layouted_rows = g_array_new(FALSE, TRUE, sizeof(Row));
 	g_array_set_clear_func(self->layouted_rows, (GDestroyNotify) row_free);
 	abort_button_tracking(self);
@@ -1810,9 +1850,8 @@ fiv_browser_init(FivBrowser *self)
 
 // --- Public interface --------------------------------------------------------
 
-// TODO(p): Later implement any arguments of this FivIoModel signal.
 static void
-on_model_files_changed(FivIoModel *model, FivBrowser *self)
+on_model_reloaded(FivIoModel *model, FivBrowser *self)
 {
 	g_return_if_fail(model == self->model);
 
@@ -1821,14 +1860,14 @@ on_model_files_changed(FivIoModel *model, FivBrowser *self)
 		selected_uri = g_strdup(self->selected->e->uri);
 
 	thumbnailers_abort(self);
-	g_array_set_size(self->entries, 0);
 	g_array_set_size(self->layouted_rows, 0);
+	g_ptr_array_set_size(self->entries, 0);
 
 	gsize len = 0;
 	FivIoModelEntry *const *files = fiv_io_model_get_files(self->model, &len);
 	for (gsize i = 0; i < len; i++) {
-		Entry e = {.e = fiv_io_model_entry_ref(files[i])};
-		g_array_append_val(self->entries, e);
+		g_ptr_array_add(
+			self->entries, entry_new(fiv_io_model_entry_ref(files[i])));
 	}
 
 	fiv_browser_select(self, selected_uri);
@@ -1838,6 +1877,55 @@ on_model_files_changed(FivIoModel *model, FivBrowser *self)
 	thumbnailers_start(self);
 }
 
+static void
+on_model_changed(FivIoModel *model, FivIoModelEntry *old, FivIoModelEntry *new,
+	FivBrowser *self)
+{
+	g_return_if_fail(model == self->model);
+
+	// Add new entries to the end, so as to not disturb the layout.
+	if (!old) {
+		g_ptr_array_add(
+			self->entries, entry_new(fiv_io_model_entry_ref(new)));
+
+		// TODO(p): Only process this one item, not everything at once.
+		// (This mainly has an effect on thumbnail-less entries.)
+		reload_thumbnails(self);
+		thumbnailers_start(self);
+		return;
+	}
+
+	Entry *found = NULL;
+	for (guint i = 0; i < self->entries->len; i++) {
+		Entry *entry = self->entries->pdata[i];
+		if (entry->e == old) {
+			found = entry;
+			break;
+		}
+	}
+	if (!found)
+		return;
+
+	// Rename entries in place, so as to not disturb the layout.
+	// XXX: This behaves differently from FivIoModel, and by extension fiv.c.
+	if (new) {
+		fiv_io_model_entry_unref(found->e);
+		found->e = fiv_io_model_entry_ref(new);
+		found->removed = FALSE;
+
+		// TODO(p): If there is a URI mismatch, don't reload thumbnails,
+		// so that there's no jumping around. Or, a bit more properly,
+		// move the thumbnail cache entry to the new URI.
+		// TODO(p): Only process this one item, not everything at once.
+		// (This mainly has an effect on thumbnail-less entries.)
+		reload_thumbnails(self);
+		thumbnailers_start(self);
+	} else {
+		found->removed = TRUE;
+		gtk_widget_queue_draw(GTK_WIDGET(self));
+	}
+}
+
 GtkWidget *
 fiv_browser_new(FivIoModel *model)
 {
@@ -1846,9 +1934,11 @@ fiv_browser_new(FivIoModel *model)
 	FivBrowser *self = g_object_new(FIV_TYPE_BROWSER, NULL);
 	self->model = g_object_ref(model);
 
-	g_signal_connect(
-		self->model, "files-changed", G_CALLBACK(on_model_files_changed), self);
-	on_model_files_changed(self->model, self);
+	g_signal_connect(self->model, "reloaded",
+		G_CALLBACK(on_model_reloaded), self);
+	g_signal_connect(self->model, "files-changed",
+		G_CALLBACK(on_model_changed), self);
+	on_model_reloaded(self->model, self);
 	return GTK_WIDGET(self);
 }
 
@@ -1877,7 +1967,7 @@ fiv_browser_select(FivBrowser *self, const char *uri)
 		return;
 
 	for (guint i = 0; i < self->entries->len; i++) {
-		const Entry *entry = &g_array_index(self->entries, Entry, i);
+		const Entry *entry = self->entries->pdata[i];
 		if (!g_strcmp0(entry->e->uri, uri)) {
 			self->selected = entry;
 			scroll_to_selection(self);
diff --git a/fiv-io-model.c b/fiv-io-model.c
index c133238..58cf632 100644
--- a/fiv-io-model.c
+++ b/fiv-io-model.c
@@ -19,12 +19,109 @@
 #include "fiv-io-model.h"
 #include "xdg.h"
 
-static GPtrArray *
-model_entry_array_new(void)
+GType
+fiv_io_model_sort_get_type(void)
+{
+	static gsize guard;
+	if (g_once_init_enter(&guard)) {
+#define XX(name) {FIV_IO_MODEL_SORT_ ## name, \
+	"FIV_IO_MODEL_SORT_" #name, #name},
+		static const GEnumValue values[] = {FIV_IO_MODEL_SORTS(XX) {}};
+#undef XX
+		GType type = g_enum_register_static(
+			g_intern_static_string("FivIoModelSort"), values);
+		g_once_init_leave(&guard, type);
+	}
+	return guard;
+}
+
+// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+
+G_DEFINE_BOXED_TYPE(FivIoModelEntry, fiv_io_model_entry,
+	fiv_io_model_entry_ref, fiv_io_model_entry_unref)
+
+FivIoModelEntry *
+fiv_io_model_entry_ref(FivIoModelEntry *self)
+{
+	return g_rc_box_acquire(self);
+}
+
+void
+fiv_io_model_entry_unref(FivIoModelEntry *self)
+{
+	g_rc_box_release(self);
+}
+
+static size_t
+entry_strsize(const char *string)
+{
+	if (!string)
+		return 0;
+
+	return strlen(string) + 1;
+}
+
+static char *
+entry_strappend(char **p, const char *string, size_t size)
 {
-	return g_ptr_array_new_with_free_func(g_rc_box_release);
+	if (!string)
+		return NULL;
+
+	char *destination = memcpy(*p, string, size);
+	*p += size;
+	return destination;
 }
 
+// See model_load_attributes for a (superset of a) list of required attributes.
+static FivIoModelEntry *
+entry_new(GFile *file, GFileInfo *info)
+{
+	gchar *uri = g_file_get_uri(file);
+	const gchar *target_uri = g_file_info_get_attribute_string(
+		info, G_FILE_ATTRIBUTE_STANDARD_TARGET_URI);
+	const gchar *display_name = g_file_info_get_display_name(info);
+
+	// TODO(p): Make it possible to use g_utf8_collate_key() instead,
+	// which does not use natural sorting.
+	gchar *parse_name = g_file_get_parse_name(file);
+	gchar *collate_key = g_utf8_collate_key_for_filename(parse_name, -1);
+	g_free(parse_name);
+
+	// The entries are immutable. Packing them into the structure
+	// should help memory usage as well as performance.
+	size_t size_uri          = entry_strsize(uri);
+	size_t size_target_uri   = entry_strsize(target_uri);
+	size_t size_display_name = entry_strsize(display_name);
+	size_t size_collate_key  = entry_strsize(collate_key);
+
+	FivIoModelEntry *entry = g_rc_box_alloc0(sizeof *entry +
+		size_uri +
+		size_target_uri +
+		size_display_name +
+		size_collate_key);
+
+	gchar *p = (gchar *) entry + sizeof *entry;
+	entry->uri          = entry_strappend(&p, uri, size_uri);
+	entry->target_uri   = entry_strappend(&p, target_uri, size_target_uri);
+	entry->display_name = entry_strappend(&p, display_name, size_display_name);
+	entry->collate_key  = entry_strappend(&p, collate_key, size_collate_key);
+
+	entry->filesize = (guint64) g_file_info_get_size(info);
+
+	GDateTime *mtime = g_file_info_get_modification_date_time(info);
+	if (mtime) {
+		entry->mtime_msec = g_date_time_to_unix(mtime) * 1000 +
+			g_date_time_get_microsecond(mtime) / 1000;
+		g_date_time_unref(mtime);
+	}
+
+	g_free(uri);
+	g_free(collate_key);
+	return entry;
+}
+
+// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+
 struct _FivIoModel {
 	GObject parent_instance;
 	GPatternSpec **supported_patterns;
@@ -51,6 +148,7 @@ enum {
 static GParamSpec *model_properties[N_PROPERTIES];
 
 enum {
+	RELOADED,
 	FILES_CHANGED,
 	SUBDIRECTORIES_CHANGED,
 	LAST_SIGNAL,
@@ -61,6 +159,13 @@ static guint model_signals[LAST_SIGNAL];
 
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 
+static GPtrArray *
+model_entry_array_new(void)
+{
+	return g_ptr_array_new_with_free_func(
+		(GDestroyNotify) fiv_io_model_entry_unref);
+}
+
 static gboolean
 model_supports(FivIoModel *self, const char *filename)
 {
@@ -124,71 +229,28 @@ model_compare(gconstpointer a, gconstpointer b, gpointer user_data)
 	return result;
 }
 
-static size_t
-model_strsize(const char *string)
-{
-	if (!string)
-		return 0;
-
-	return strlen(string) + 1;
-}
+static const char *model_load_attributes =
+	G_FILE_ATTRIBUTE_STANDARD_TYPE ","
+	G_FILE_ATTRIBUTE_STANDARD_NAME ","
+	G_FILE_ATTRIBUTE_STANDARD_SIZE ","
+	G_FILE_ATTRIBUTE_STANDARD_DISPLAY_NAME ","
+	G_FILE_ATTRIBUTE_STANDARD_TARGET_URI ","
+	G_FILE_ATTRIBUTE_STANDARD_IS_HIDDEN ","
+	G_FILE_ATTRIBUTE_TIME_MODIFIED ","
+	G_FILE_ATTRIBUTE_TIME_MODIFIED_USEC;
 
-static char *
-model_strappend(char **p, const char *string, size_t size)
+static GPtrArray *
+model_decide_placement(
+	FivIoModel *self, GFileInfo *info, GPtrArray *subdirs, GPtrArray *files)
 {
-	if (!string)
+	if (self->filtering && g_file_info_get_is_hidden(info))
 		return NULL;
-
-	char *destination = memcpy(*p, string, size);
-	*p += size;
-	return destination;
-}
-
-static FivIoModelEntry *
-model_entry_new(GFile *file, GFileInfo *info)
-{
-	gchar *uri = g_file_get_uri(file);
-	const gchar *target_uri = g_file_info_get_attribute_string(
-		info, G_FILE_ATTRIBUTE_STANDARD_TARGET_URI);
-	const gchar *display_name = g_file_info_get_display_name(info);
-
-	// TODO(p): Make it possible to use g_utf8_collate_key() instead,
-	// which does not use natural sorting.
-	gchar *parse_name = g_file_get_parse_name(file);
-	gchar *collate_key = g_utf8_collate_key_for_filename(parse_name, -1);
-	g_free(parse_name);
-
-	// The entries are immutable. Packing them into the structure
-	// should help memory usage as well as performance.
-	size_t size_uri          = model_strsize(uri);
-	size_t size_target_uri   = model_strsize(target_uri);
-	size_t size_display_name = model_strsize(display_name);
-	size_t size_collate_key  = model_strsize(collate_key);
-
-	FivIoModelEntry *entry = g_rc_box_alloc0(sizeof *entry +
-		size_uri +
-		size_target_uri +
-		size_display_name +
-		size_collate_key);
-
-	gchar *p = (gchar *) entry + sizeof *entry;
-	entry->uri          = model_strappend(&p, uri, size_uri);
-	entry->target_uri   = model_strappend(&p, target_uri, size_target_uri);
-	entry->display_name = model_strappend(&p, display_name, size_display_name);
-	entry->collate_key  = model_strappend(&p, collate_key, size_collate_key);
-
-	entry->filesize = (guint64) g_file_info_get_size(info);
-
-	GDateTime *mtime = g_file_info_get_modification_date_time(info);
-	if (mtime) {
-		entry->mtime_msec = g_date_time_to_unix(mtime) * 1000 +
-			g_date_time_get_microsecond(mtime) / 1000;
-		g_date_time_unref(mtime);
-	}
-
-	g_free(uri);
-	g_free(collate_key);
-	return entry;
+	if (g_file_info_get_file_type(info) == G_FILE_TYPE_DIRECTORY)
+		return subdirs;
+	if (!self->filtering ||
+		model_supports(self, g_file_info_get_name(info)))
+		return files;
+	return NULL;
 }
 
 static gboolean
@@ -200,16 +262,8 @@ model_reload_to(FivIoModel *self, GFile *directory,
 	if (files)
 		g_ptr_array_set_size(files, 0);
 
-	GFileEnumerator *enumerator = g_file_enumerate_children(directory,
-		G_FILE_ATTRIBUTE_STANDARD_TYPE ","
-		G_FILE_ATTRIBUTE_STANDARD_NAME ","
-		G_FILE_ATTRIBUTE_STANDARD_SIZE ","
-		G_FILE_ATTRIBUTE_STANDARD_DISPLAY_NAME ","
-		G_FILE_ATTRIBUTE_STANDARD_TARGET_URI ","
-		G_FILE_ATTRIBUTE_STANDARD_IS_HIDDEN ","
-		G_FILE_ATTRIBUTE_TIME_MODIFIED ","
-		G_FILE_ATTRIBUTE_TIME_MODIFIED_USEC,
-		G_FILE_QUERY_INFO_NONE, NULL, error);
+	GFileEnumerator *enumerator = g_file_enumerate_children(
+		directory, model_load_attributes, G_FILE_QUERY_INFO_NONE, NULL, error);
 	if (!enumerator)
 		return FALSE;
 
@@ -225,18 +279,11 @@ model_reload_to(FivIoModel *self, GFile *directory,
 		}
 		if (!info)
 			break;
-		if (self->filtering && g_file_info_get_is_hidden(info))
-			continue;
-
-		GPtrArray *target = NULL;
-		if (g_file_info_get_file_type(info) == G_FILE_TYPE_DIRECTORY)
-			target = subdirs;
-		else if (!self->filtering ||
-			model_supports(self, g_file_info_get_name(info)))
-			target = files;
 
+		GPtrArray *target =
+			model_decide_placement(self, info, subdirs, files);
 		if (target)
-			g_ptr_array_add(target, model_entry_new(child, info));
+			g_ptr_array_add(target, entry_new(child, info));
 	}
 	g_object_unref(enumerator);
 
@@ -253,9 +300,7 @@ model_reload(FivIoModel *self, GError **error)
 	// Note that this will clear all entries on failure.
 	gboolean result = model_reload_to(
 		self, self->directory, self->subdirs, self->files, error);
-
-	g_signal_emit(self, model_signals[FILES_CHANGED], 0);
-	g_signal_emit(self, model_signals[SUBDIRECTORIES_CHANGED], 0);
+	g_signal_emit(self, model_signals[RELOADED], 0);
 	return result;
 }
 
@@ -264,9 +309,144 @@ model_resort(FivIoModel *self)
 {
 	g_ptr_array_sort_with_data(self->subdirs, model_compare, self);
 	g_ptr_array_sort_with_data(self->files, model_compare, self);
+	g_signal_emit(self, model_signals[RELOADED], 0);
+}
+
+// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 
-	g_signal_emit(self, model_signals[FILES_CHANGED], 0);
-	g_signal_emit(self, model_signals[SUBDIRECTORIES_CHANGED], 0);
+static gint
+model_find(const GPtrArray *target, GFile *file, FivIoModelEntry **entry)
+{
+	for (guint i = 0; i < target->len; i++) {
+		FivIoModelEntry *e = target->pdata[i];
+		GFile *f = g_file_new_for_uri(e->uri);
+		gboolean match = g_file_equal(f, file);
+		g_object_unref(f);
+		if (match) {
+			*entry = e;
+			return i;
+		}
+	}
+	return -1;
+}
+
+static void
+on_monitor_changed(G_GNUC_UNUSED GFileMonitor *monitor, GFile *file,
+	GFile *other_file, GFileMonitorEvent event_type, gpointer user_data)
+{
+	FivIoModel *self = user_data;
+
+	FivIoModelEntry *old_entry = NULL;
+	gint files_index = model_find(self->files, file, &old_entry);
+	gint subdirs_index = model_find(self->subdirs, file, &old_entry);
+
+	enum { NONE, CHANGING, RENAMING, REMOVING, ADDING } action = NONE;
+	GFile *new_entry_file = NULL;
+	switch (event_type) {
+	case G_FILE_MONITOR_EVENT_CHANGED:
+	case G_FILE_MONITOR_EVENT_ATTRIBUTE_CHANGED:
+		action = CHANGING;
+		new_entry_file = file;
+		break;
+	case G_FILE_MONITOR_EVENT_RENAMED:
+		action = RENAMING;
+		new_entry_file = other_file;
+		break;
+	case G_FILE_MONITOR_EVENT_DELETED:
+	case G_FILE_MONITOR_EVENT_MOVED_OUT:
+		action = REMOVING;
+		break;
+	case G_FILE_MONITOR_EVENT_CREATED:
+	case G_FILE_MONITOR_EVENT_MOVED_IN:
+		action = ADDING;
+		old_entry = NULL;
+		new_entry_file = file;
+		break;
+
+	case G_FILE_MONITOR_EVENT_CHANGES_DONE_HINT:
+		// TODO(p): Figure out if we can't make use of _CHANGES_DONE_HINT.
+	case G_FILE_MONITOR_EVENT_PRE_UNMOUNT:
+	case G_FILE_MONITOR_EVENT_UNMOUNTED:
+		// TODO(p): Figure out how to handle _UNMOUNTED sensibly.
+	case G_FILE_MONITOR_EVENT_MOVED:
+		return;
+	}
+
+	FivIoModelEntry *new_entry = NULL;
+	GPtrArray *new_target = NULL;
+	if (new_entry_file) {
+		GError *error = NULL;
+		GFileInfo *info = g_file_query_info(new_entry_file,
+			model_load_attributes, G_FILE_QUERY_INFO_NONE, NULL, &error);
+		if (error) {
+			g_debug("monitor: %s", error->message);
+			g_error_free(error);
+			goto run;
+		}
+
+		if ((new_target =
+			model_decide_placement(self, info, self->subdirs, self->files)))
+			new_entry = entry_new(new_entry_file, info);
+		g_object_unref(info);
+
+		if ((files_index != -1 && new_target == self->subdirs) ||
+			(subdirs_index != -1 && new_target == self->files)) {
+			g_debug("monitor: ignoring transfer between files and subdirs");
+			goto out;
+		}
+	}
+
+run:
+	// Keep a reference alive so that signal handlers see the new arrays.
+	if (old_entry)
+		fiv_io_model_entry_ref(old_entry);
+
+	if (files_index != -1 || new_target == self->files) {
+		if (action == CHANGING) {
+			g_assert(new_entry != NULL);
+			fiv_io_model_entry_unref(self->files->pdata[files_index]);
+			self->files->pdata[files_index] =
+				fiv_io_model_entry_ref(new_entry);
+		}
+		if (action == REMOVING || action == RENAMING)
+			g_ptr_array_remove_index(self->files, files_index);
+		if (action == RENAMING || action == ADDING) {
+			g_assert(new_entry != NULL);
+			g_ptr_array_add(self->files, fiv_io_model_entry_ref(new_entry));
+		}
+
+		g_signal_emit(self, model_signals[FILES_CHANGED],
+			0, old_entry, new_entry);
+	}
+	if (subdirs_index != -1 || new_target == self->subdirs) {
+		if (action == CHANGING) {
+			g_assert(new_entry != NULL);
+			fiv_io_model_entry_unref(self->subdirs->pdata[subdirs_index]);
+			self->subdirs->pdata[subdirs_index] =
+				fiv_io_model_entry_ref(new_entry);
+		}
+		if (action == REMOVING || action == RENAMING)
+			g_ptr_array_remove_index(self->subdirs, subdirs_index);
+		if (action == RENAMING || action == ADDING) {
+			g_assert(new_entry != NULL);
+			g_ptr_array_add(self->subdirs, fiv_io_model_entry_ref(new_entry));
+		}
+
+		g_signal_emit(self, model_signals[SUBDIRECTORIES_CHANGED],
+			0, old_entry, new_entry);
+	}
+
+	// NOTE: It would make sense to do
+	//   g_ptr_array_sort_with_data(self->{files,subdirs}, model_compare, self);
+	// but then the iteration behaviour of fiv.c would differ from what's shown
+	// in the browser. Perhaps we need to use an index-based, fully-synchronized
+	// interface similar to GListModel::items-changed.
+
+	if (old_entry)
+		fiv_io_model_entry_unref(old_entry);
+out:
+	if (new_entry)
+		fiv_io_model_entry_unref(new_entry);
 }
 
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@@ -406,7 +586,7 @@ fiv_io_model_get_property(
 		g_value_set_boolean(value, self->filtering);
 		break;
 	case PROP_SORT_FIELD:
-		g_value_set_int(value, self->sort_field);
+		g_value_set_enum(value, self->sort_field);
 		break;
 	case PROP_SORT_DESCENDING:
 		g_value_set_boolean(value, self->sort_descending);
@@ -430,8 +610,8 @@ fiv_io_model_set_property(
 		}
 		break;
 	case PROP_SORT_FIELD:
-		if ((int) self->sort_field != g_value_get_int(value)) {
-			self->sort_field = g_value_get_int(value);
+		if ((int) self->sort_field != g_value_get_enum(value)) {
+			self->sort_field = g_value_get_enum(value);
 			g_object_notify_by_pspec(object, model_properties[property_id]);
 			model_resort(self);
 		}
@@ -459,24 +639,28 @@ fiv_io_model_class_init(FivIoModelClass *klass)
 	model_properties[PROP_FILTERING] = g_param_spec_boolean(
 		"filtering", "Filtering", "Only show non-hidden, supported entries",
 		TRUE, G_PARAM_READWRITE);
-	// TODO(p): GObject enumerations are annoying, but this should be one.
-	model_properties[PROP_SORT_FIELD] = g_param_spec_int(
+	model_properties[PROP_SORT_FIELD] = g_param_spec_enum(
 		"sort-field", "Sort field", "Sort order",
-		FIV_IO_MODEL_SORT_MIN, FIV_IO_MODEL_SORT_MAX,
-		FIV_IO_MODEL_SORT_NAME, G_PARAM_READWRITE);
+		FIV_TYPE_IO_MODEL_SORT, FIV_IO_MODEL_SORT_NAME, G_PARAM_READWRITE);
 	model_properties[PROP_SORT_DESCENDING] = g_param_spec_boolean(
 		"sort-descending", "Sort descending", "Use reverse sort order",
 		FALSE, G_PARAM_READWRITE);
 	g_object_class_install_properties(
 		object_class, N_PROPERTIES, model_properties);
 
-	// TODO(p): Arguments something like: index, added, removed.
+	// All entries might have changed.
+	model_signals[RELOADED] =
+		g_signal_new("reloaded", G_TYPE_FROM_CLASS(klass), 0, 0,
+			NULL, NULL, NULL, G_TYPE_NONE, 0);
+
 	model_signals[FILES_CHANGED] =
 		g_signal_new("files-changed", G_TYPE_FROM_CLASS(klass), 0, 0,
-			NULL, NULL, NULL, G_TYPE_NONE, 0);
+			NULL, NULL, NULL,
+			G_TYPE_NONE, 2, FIV_TYPE_IO_MODEL_ENTRY, FIV_TYPE_IO_MODEL_ENTRY);
 	model_signals[SUBDIRECTORIES_CHANGED] =
 		g_signal_new("subdirectories-changed", G_TYPE_FROM_CLASS(klass), 0, 0,
-			NULL, NULL, NULL, G_TYPE_NONE, 0);
+			NULL, NULL, NULL,
+			G_TYPE_NONE, 2, FIV_TYPE_IO_MODEL_ENTRY, FIV_TYPE_IO_MODEL_ENTRY);
 }
 
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@@ -511,9 +695,15 @@ fiv_io_model_open(FivIoModel *self, GFile *directory, GError **error)
 	g_clear_object(&self->monitor);
 	self->directory = g_object_ref(directory);
 
-	// TODO(p): Process the ::changed signal.
-	self->monitor = g_file_monitor_directory(
-		directory, G_FILE_MONITOR_WATCH_MOVES, NULL, NULL /* error */);
+	GError *e = NULL;
+	if ((self->monitor = g_file_monitor_directory(
+			 directory, G_FILE_MONITOR_WATCH_MOVES, NULL, &e))) {
+		g_signal_connect(self->monitor, "changed",
+			G_CALLBACK(on_monitor_changed), self);
+	} else {
+		g_debug("directory monitoring failed: %s", e->message);
+		g_error_free(e);
+	}
 	return model_reload(self, error);
 }
 
diff --git a/fiv-io-model.h b/fiv-io-model.h
index 2fb9ad7..c785130 100644
--- a/fiv-io-model.h
+++ b/fiv-io-model.h
@@ -20,15 +20,39 @@
 #include <gio/gio.h>
 #include <glib.h>
 
+// Avoid glib-mkenums.
 typedef enum _FivIoModelSort {
-	FIV_IO_MODEL_SORT_NAME,
-	FIV_IO_MODEL_SORT_MTIME,
-	FIV_IO_MODEL_SORT_COUNT,
-
-	FIV_IO_MODEL_SORT_MIN = 0,
-	FIV_IO_MODEL_SORT_MAX = FIV_IO_MODEL_SORT_COUNT - 1
+#define FIV_IO_MODEL_SORTS(XX) \
+	XX(NAME) \
+	XX(MTIME)
+#define XX(name) FIV_IO_MODEL_SORT_ ## name,
+	FIV_IO_MODEL_SORTS(XX)
+#undef XX
+	FIV_IO_MODEL_SORT_COUNT
 } FivIoModelSort;
 
+GType fiv_io_model_sort_get_type(void) G_GNUC_CONST;
+#define FIV_TYPE_IO_MODEL_SORT (fiv_io_model_sort_get_type())
+
+// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+
+typedef struct {
+	const char *uri;                    ///< GIO URI
+	const char *target_uri;             ///< GIO URI for any target
+	const char *display_name;           ///< Label for the file
+	const char *collate_key;            ///< Collate key for the filename
+	guint64 filesize;                   ///< Filesize in bytes
+	gint64 mtime_msec;                  ///< Modification time in milliseconds
+} FivIoModelEntry;
+
+GType fiv_io_model_entry_get_type(void) G_GNUC_CONST;
+#define FIV_TYPE_IO_MODEL_ENTRY (fiv_io_model_entry_get_type())
+
+FivIoModelEntry *fiv_io_model_entry_ref(FivIoModelEntry *self);
+void fiv_io_model_entry_unref(FivIoModelEntry *self);
+
+// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+
 #define FIV_TYPE_IO_MODEL (fiv_io_model_get_type())
 G_DECLARE_FINAL_TYPE(FivIoModel, fiv_io_model, FIV, IO_MODEL, GObject)
 
@@ -44,18 +68,5 @@ GFile *fiv_io_model_get_previous_directory(FivIoModel *self);
 /// Returns the next VFS directory in order, or NULL.
 GFile *fiv_io_model_get_next_directory(FivIoModel *self);
 
-// These objects are reference-counted using GRcBox.
-typedef struct {
-	const char *uri;                    ///< GIO URI
-	const char *target_uri;             ///< GIO URI for any target
-	const char *display_name;           ///< Label for the file
-	const char *collate_key;            ///< Collate key for the filename
-	guint64 filesize;                   ///< Filesize in bytes
-	gint64 mtime_msec;                  ///< Modification time in milliseconds
-} FivIoModelEntry;
-
-#define fiv_io_model_entry_ref(e)    g_rc_box_acquire(e)
-#define fiv_io_model_entry_unref(e)  g_rc_box_release(e)
-
 FivIoModelEntry *const *fiv_io_model_get_files(FivIoModel *self, gsize *len);
 FivIoModelEntry *const *fiv_io_model_get_subdirs(FivIoModel *self, gsize *len);
diff --git a/fiv-sidebar.c b/fiv-sidebar.c
index 6525067..caf2d86 100644
--- a/fiv-sidebar.c
+++ b/fiv-sidebar.c
@@ -623,9 +623,9 @@ fiv_sidebar_new(FivIoModel *model)
 	gtk_container_set_focus_vadjustment(GTK_CONTAINER(sidebar_port),
 		gtk_scrolled_window_get_vadjustment(GTK_SCROLLED_WINDOW(self)));
 
-	// TODO(p): There should be an extra signal to watch location changes only.
+	// TODO(p): Also connect to and process the subdirectories-changed signal.
 	self->model = g_object_ref(model);
-	g_signal_connect_swapped(self->model, "subdirectories-changed",
+	g_signal_connect_swapped(self->model, "reloaded",
 		G_CALLBACK(update_location), self);
 
 	return GTK_WIDGET(self);
diff --git a/fiv-thumbnail.h b/fiv-thumbnail.h
index 05c3dc1..0d53c01 100644
--- a/fiv-thumbnail.h
+++ b/fiv-thumbnail.h
@@ -21,7 +21,7 @@
 #include <gio/gio.h>
 #include <glib.h>
 
-// And this is how you avoid glib-mkenums.
+// Avoid glib-mkenums.
 typedef enum _FivThumbnailSize {
 #define FIV_THUMBNAIL_SIZES(XX) \
 	XX(SMALL,  128, "normal") \
diff --git a/fiv.c b/fiv.c
index dad88e2..3911cec 100644
--- a/fiv.c
+++ b/fiv.c
@@ -733,7 +733,7 @@ load_directory_without_switching(const char *uri)
 	GError *error = NULL;
 	GFile *file = g_file_new_for_uri(g.directory);
 	if (fiv_io_model_open(g.model, file, &error)) {
-		// This is handled by our ::files-changed callback.
+		// This is handled by our ::reloaded callback.
 	} else if (g_error_matches(error, G_IO_ERROR, G_IO_ERROR_NOT_SUPPORTED)) {
 		g_error_free(error);
 	} else {
@@ -797,7 +797,7 @@ go_forward(void)
 }
 
 static void
-on_model_files_changed(FivIoModel *model, G_GNUC_UNUSED gpointer user_data)
+on_model_reloaded(FivIoModel *model, G_GNUC_UNUSED gpointer user_data)
 {
 	g_return_if_fail(model == g.model);
 
@@ -811,6 +811,13 @@ on_model_files_changed(FivIoModel *model, G_GNUC_UNUSED gpointer user_data)
 }
 
 static void
+on_model_files_changed(FivIoModel *model, G_GNUC_UNUSED FivIoModelEntry *old,
+	G_GNUC_UNUSED FivIoModelEntry *new, G_GNUC_UNUSED gpointer user_data)
+{
+	on_model_reloaded(model, NULL);
+}
+
+static void
 on_sidebar_toggled(GtkToggleButton *button, G_GNUC_UNUSED gpointer user_data)
 {
 	gboolean active = gtk_toggle_button_get_active(button);
@@ -838,7 +845,8 @@ on_sort_field(G_GNUC_UNUSED GtkToggleButton *button, gpointer data)
 	if (!active)
 		return;
 
-	int old = -1, new = (int) (intptr_t) data;
+	FivIoModelSort old = FIV_IO_MODEL_SORT_COUNT;
+	FivIoModelSort new = (FivIoModelSort) (intptr_t) data;
 	g_object_get(g.model, "sort-field", &old, NULL);
 	if (old != new)
 		g_object_set(g.model, "sort-field", new, NULL);
@@ -1206,7 +1214,7 @@ static void
 on_notify_thumbnail_size(
 	GObject *object, GParamSpec *param_spec, G_GNUC_UNUSED gpointer user_data)
 {
-	FivThumbnailSize size = 0;
+	FivThumbnailSize size = FIV_THUMBNAIL_SIZE_COUNT;
 	g_object_get(object, g_param_spec_get_name(param_spec), &size, NULL);
 	gtk_widget_set_sensitive(
 		g.browsebar[BROWSEBAR_PLUS], size < FIV_THUMBNAIL_SIZE_MAX);
@@ -2253,6 +2261,8 @@ main(int argc, char *argv[])
 	fiv_collection_register();
 
 	g.model = g_object_new(FIV_TYPE_IO_MODEL, NULL);
+	g_signal_connect(g.model, "reloaded",
+		G_CALLBACK(on_model_reloaded), NULL);
 	g_signal_connect(g.model, "files-changed",
 		G_CALLBACK(on_model_files_changed), NULL);