[polari] tabCompletion: Do not use focus to move selection

[Florian Müllner <fmuellner src gnome org>]

commit 24ff6c36dd66a0e61cfe858f7a31db66e5c68b1d
Author: Florian Müllner <fmuellner gnome org>
Date:   Fri Jul 2 23:05:16 2021 +0200

    tabCompletion: Do not use focus to move selection
    
    Using the `move-cursor` action signal is a neat trick, but relies
    on completions using a separate window to not move the focus from
    the entry. This is about to change, so work out the next/previous
    visible row ourselves instead of piggy-backing on keynav.
    
    https://gitlab.gnome.org/GNOME/polari/-/merge_requests/198

 src/tabCompletion.js | 24 ++++++++----------------
 1 file changed, 8 insertions(+), 16 deletions(-)
---
diff --git a/src/tabCompletion.js b/src/tabCompletion.js
index 8f85ce5d..340eb012 100644
--- a/src/tabCompletion.js
+++ b/src/tabCompletion.js
@@ -32,7 +32,6 @@ const TabCompletion = class {
         this._list.set_filter_func(this._filter.bind(this));
         this._list.connect('row-selected', this._onRowSelected.bind(this));
         this._list.connect('row-activated', this._stop.bind(this));
-        this._list.connect('keynav-failed', this._onKeynavFailed.bind(this));
         frame.add(this._list);
 
         this._widgetMap = new Map();
@@ -138,11 +137,11 @@ const TabCompletion = class {
         switch (keyval) {
         case Gdk.KEY_Tab:
         case Gdk.KEY_Down:
-            this._moveSelection(Gtk.MovementStep.DISPLAY_LINES, 1);
+            this._moveSelection(1);
             return Gdk.EVENT_STOP;
         case Gdk.KEY_ISO_Left_Tab:
         case Gdk.KEY_Up:
-            this._moveSelection(Gtk.MovementStep.DISPLAY_LINES, -1);
+            this._moveSelection(-1);
             return Gdk.EVENT_STOP;
         case Gdk.KEY_Escape:
             this._cancel();
@@ -233,19 +232,12 @@ const TabCompletion = class {
         }
     }
 
-    _onKeynavFailed(w, dir) {
-        if (this._inHandler)
-            return Gdk.EVENT_PROPAGATE;
-        let count = dir === Gtk.DirectionType.DOWN ? -1 : 1;
-        this._inHandler = true;
-        this._moveSelection(Gtk.MovementStep.BUFFER_ENDS, count);
-        this._inHandler = false;
-        return Gdk.EVENT_STOP;
-    }
-
-    _moveSelection(movement, count) {
-        this._list.emit('move-cursor', movement, count);
-        let row = this._list.get_focus_child();
+    _moveSelection(count) {
+        const rows = this._list.get_children().filter(c => c.get_child_visible());
+        const current = this._list.get_selected_row();
+        const index = current ? rows.findIndex(r => r === current) : 0;
+        const newIndex = (index + rows.length + count) % rows.length;
+        const row = rows[newIndex];
         this._list.select_row(row);
     }