files-view: Replace REMOVE_FILE with REMOVE_FILESwip/corey/performance-remove-files

Files are added in bulk to the view with ADD_FILES, but then removed
from the view with REMOVE_FILE, which takes a single file.  This is very
inefficient in the case where a large number of items are deleted. In
other words, if you delete a folder with 1,000 items, the process
completes very quickly, but if you delete the 1,000 items, Nautilus will
hang for an extended period of time. This can be a common problem if
the view is current showing Trash, and the the trash is emptied.

5 files changed, 120 insertions, 32 deletions

diff --git a/src/nautilus-files-view.c b/src/nautilus-files-view.c
index 01028dd58..aeefce69c 100644
--- a/src/nautilus-files-view.c
+++ b/src/nautilus-files-view.c
@@ -129,7 +129,7 @@ enum
     END_LOADING,
     FILE_CHANGED,
     MOVE_COPY_ITEMS,
-    REMOVE_FILE,
+    REMOVE_FILES,
     SELECTION_CHANGED,
     TRASH,
     DELETE,
@@ -4336,6 +4336,8 @@ process_old_files (NautilusFilesView *view)
 
     if (files_added != NULL || files_changed != NULL)
     {
+        NautilusDirectory *prev_directory = NULL;
+        GList *files_removed = NULL;
         gboolean send_selection_change = FALSE;
 
         g_signal_emit (view, signals[BEGIN_FILE_CHANGES], 0);
@@ -4365,9 +4367,22 @@ process_old_files (NautilusFilesView *view)
             gboolean should_show_file;
             pending = node->data;
             should_show_file = still_should_show_file (view, pending);
-            g_signal_emit (view,
-                           signals[should_show_file ? FILE_CHANGED : REMOVE_FILE], 0,
-                           pending->file, pending->directory);
+            if (should_show_file)
+            {
+                g_signal_emit (view,
+                               signals[FILE_CHANGED], 0, pending->file, pending->directory);
+            }
+            else
+            {
+                if (prev_directory != NULL && prev_directory != pending->directory)
+                {
+                    g_signal_emit (view, signals[REMOVE_FILES], 0,
+                                   files_removed, pending->directory);
+                    g_clear_pointer (&files_removed, g_list_free);
+                }
+
+                files_removed = g_list_prepend (files_removed, pending->file);
+            }
 
             /* Acknowledge the files that were pending to be revealed */
             if (g_hash_table_contains (priv->pending_reveal, pending->file))
@@ -4386,6 +4401,12 @@ process_old_files (NautilusFilesView *view)
             }
         }
 
+        if (files_removed != NULL)
+        {
+            g_signal_emit (view, signals[REMOVE_FILES], 0,
+                           files_removed, pending->directory);
+            g_clear_pointer (&files_removed, g_list_free);
+        }
         if (files_changed != NULL)
         {
             g_autolist (NautilusFile) selection = NULL;
@@ -9570,14 +9591,14 @@ nautilus_files_view_class_init (NautilusFilesViewClass *klass)
                       NULL, NULL,
                       g_cclosure_marshal_generic,
                       G_TYPE_NONE, 2, NAUTILUS_TYPE_FILE, NAUTILUS_TYPE_DIRECTORY);
-    signals[REMOVE_FILE] =
+    signals[REMOVE_FILES] =
         g_signal_new ("remove-file",
                       G_TYPE_FROM_CLASS (klass),
                       G_SIGNAL_RUN_LAST,
-                      G_STRUCT_OFFSET (NautilusFilesViewClass, remove_file),
+                      G_STRUCT_OFFSET (NautilusFilesViewClass, remove_files),
                       NULL, NULL,
                       g_cclosure_marshal_generic,
-                      G_TYPE_NONE, 2, NAUTILUS_TYPE_FILE, NAUTILUS_TYPE_DIRECTORY);
+                      G_TYPE_NONE, 2, G_TYPE_POINTER, NAUTILUS_TYPE_DIRECTORY);
     signals[SELECTION_CHANGED] =
         g_signal_new ("selection-changed",
                       G_TYPE_FROM_CLASS (klass),
diff --git a/src/nautilus-files-view.h b/src/nautilus-files-view.h
index 536c613f6..2e088c364 100644
--- a/src/nautilus-files-view.h
+++ b/src/nautilus-files-view.h
@@ -60,8 +60,8 @@ struct _NautilusFilesViewClass {
          */
         void    (* add_files)                    (NautilusFilesView *view,
                                                   GList             *files);
-        void    (* remove_file)                 (NautilusFilesView *view,
-                                                 NautilusFile      *file,
+        void    (* remove_files)                 (NautilusFilesView *view,
+                                                 GList             *files,
                                                  NautilusDirectory *directory);
 
         /* The 'file_changed' signal is emitted to signal a change in a file,
diff --git a/src/nautilus-list-base.c b/src/nautilus-list-base.c
index cb0c2fa81..00deee8e7 100644
--- a/src/nautilus-list-base.c
+++ b/src/nautilus-list-base.c
@@ -1160,18 +1160,30 @@ real_end_file_changes (NautilusFilesView *files_view)
 }
 
 static void
-real_remove_file (NautilusFilesView *files_view,
-                  NautilusFile      *file,
-                  NautilusDirectory *directory)
+real_remove_files (NautilusFilesView *files_view,
+                   GList             *files,
+                   NautilusDirectory *directory)
 {
     NautilusListBase *self = NAUTILUS_LIST_BASE (files_view);
     NautilusListBasePrivate *priv = nautilus_list_base_get_instance_private (self);
-    NautilusViewItem *item;
+    g_autoptr (GList) items = NULL;
 
-    item = nautilus_view_model_get_item_from_file (priv->model, file);
-    if (item != NULL)
+
+    for (GList *l = files; l != NULL; l = l->next)
+    {
+        NautilusViewItem *item;
+
+        item = nautilus_view_model_get_item_from_file (priv->model, l->data);
+
+        if (item != NULL)
+        {
+            items = g_list_prepend (items, item);
+        }
+    }
+
+    if (items != NULL)
     {
-        nautilus_view_model_remove_item (priv->model, item, directory);
+        nautilus_view_model_remove_items (priv->model, items, directory);
     }
 }
 
@@ -1813,7 +1825,7 @@ nautilus_list_base_class_init (NautilusListBaseClass *klass)
     files_view_class->get_selection = real_get_selection;
     files_view_class->get_selection_for_file_transfer = real_get_selection_for_file_transfer;
     files_view_class->is_empty = real_is_empty;
-    files_view_class->remove_file = real_remove_file;
+    files_view_class->remove_files = real_remove_files;
     files_view_class->select_all = real_select_all;
     files_view_class->set_selection = real_set_selection;
     files_view_class->invert_selection = real_invert_selection;
diff --git a/src/nautilus-view-model.c b/src/nautilus-view-model.c
index 4ee2c9037..c41995fbc 100644
--- a/src/nautilus-view-model.c
+++ b/src/nautilus-view-model.c
@@ -395,28 +395,83 @@ nautilus_view_model_get_item_from_file (NautilusViewModel *self,
     return g_hash_table_lookup (self->map_files_to_model, file);
 }
 
+static gint
+sort_for_model (gconstpointer a,
+                gconstpointer b,
+                gpointer      user_data)
+{
+    GListStore *store = user_data;
+
+    guint pos_a, pos_b;
+
+    g_list_store_find (store, (gpointer) a, &pos_a);
+    g_list_store_find (store, (gpointer) b, &pos_b);
+
+    if (pos_a < pos_b)
+    {
+        return -1;
+    }
+    else if (pos_a > pos_b)
+    {
+        return 1;
+    }
+    else
+    {
+        return 0;
+    }
+}
+
 void
-nautilus_view_model_remove_item (NautilusViewModel *self,
-                                 NautilusViewItem  *item,
-                                 NautilusDirectory *directory)
+nautilus_view_model_remove_items (NautilusViewModel *self,
+                                  GList             *items,
+                                  NautilusDirectory *directory)
 {
-    NautilusFile *file;
-    g_autoptr (NautilusFile) parent = NULL;
-    GListStore *dir_store;
-    guint i;
+    g_autoptr (NautilusFile) parent = nautilus_directory_get_corresponding_file (directory);
+    GListStore *dir_store = get_directory_store (self, parent);
+    guint start, i;
+    guint n_items_in_range = 0;
 
-    file = nautilus_view_item_get_file (item);
-    parent = nautilus_directory_get_corresponding_file (directory);
-    dir_store = get_directory_store (self, parent);
-    if (g_list_store_find (dir_store, item, &i))
+    /* The order of the items in the directory store, is not necessarily the order
+     * that we received them in.  Let's sort the items according to the sort on
+     * the directory store to minimize the calls to ::items-changed. */
+    items = g_list_sort_with_data (items, sort_for_model, dir_store);
+
+    /* Reverse the sort so that removing items doesn't impact the index */
+    items = g_list_reverse (items);
+
+    for (GList *l = items; l != NULL; l = l->next)
     {
-        g_list_store_remove (dir_store, i);
+        NautilusViewItem *item = l->data;
+        NautilusFile *file = nautilus_view_item_get_file (item);
+
+        if (g_list_store_find (dir_store, item, &i))
+        {
+            if (n_items_in_range > 0 && i != start - 1)
+            {
+                g_list_store_splice (dir_store, start, n_items_in_range, 0, 0);
+                n_items_in_range = 0;
+            }
+
+            /* `start` is a moving target that gets decremented as we move down the list */
+            start = i;
+            n_items_in_range++;
+        }
+        else
+        {
+            g_warning ("Failed to remove item %s", nautilus_file_get_uri (file));
+        }
+
         g_hash_table_remove (self->map_files_to_model, file);
         if (nautilus_file_is_directory (file))
         {
             g_hash_table_remove (self->directory_reverse_map, file);
         }
     }
+
+    if (n_items_in_range > 0)
+    {
+        g_list_store_splice (dir_store, start, n_items_in_range, 0, 0);
+    }
 }
 
 void
diff --git a/src/nautilus-view-model.h b/src/nautilus-view-model.h
index 718412652..89b3c3713 100644
--- a/src/nautilus-view-model.h
+++ b/src/nautilus-view-model.h
@@ -21,9 +21,9 @@ NautilusViewItem * nautilus_view_model_get_item_from_file (NautilusViewModel *se
 GQueue * nautilus_view_model_get_items_from_files (NautilusViewModel *self,
                                                    GQueue            *files);
 /* Don't use inside a loop, use nautilus_view_model_remove_all_items instead. */
-void nautilus_view_model_remove_item (NautilusViewModel     *self,
-                                      NautilusViewItem      *item,
-                                      NautilusDirectory     *directory);
+void nautilus_view_model_remove_items (NautilusViewModel     *self,
+                                       GList                 *items,
+                                       NautilusDirectory     *directory);
 void nautilus_view_model_remove_all_items (NautilusViewModel *self);
 /* Don't use inside a loop, use nautilus_view_model_add_items instead. */
 void nautilus_view_model_add_item (NautilusViewModel     *self,