From 9f8d518e829b1c0b35258f5124c9ca77bd974c88 Mon Sep 17 00:00:00 2001
From: AnotherTest <ali.mpfard@gmail.com>
Date: Thu, 18 Mar 2021 20:58:58 +0330
Subject: [PATCH] Spreadsheet: Only append new columns/rows every 50ms

Fixes #5550.
---
 .../Spreadsheet/SpreadsheetView.cpp           | 24 ++++++++++++++-----
 .../Spreadsheet/SpreadsheetView.h             |  7 ++++++
 2 files changed, 25 insertions(+), 6 deletions(-)

diff --git a/Userland/Applications/Spreadsheet/SpreadsheetView.cpp b/Userland/Applications/Spreadsheet/SpreadsheetView.cpp
index 019b9b118a..8e49a2b162 100644
--- a/Userland/Applications/Spreadsheet/SpreadsheetView.cpp
+++ b/Userland/Applications/Spreadsheet/SpreadsheetView.cpp
@@ -69,13 +69,25 @@ void InfinitelyScrollableTableView::did_scroll()
     TableView::did_scroll();
     auto& vscrollbar = vertical_scrollbar();
     auto& hscrollbar = horizontal_scrollbar();
-    if (vscrollbar.is_visible() && vscrollbar.value() == vscrollbar.max()) {
-        if (on_reaching_vertical_end)
-            on_reaching_vertical_end();
+    if (!m_vertical_scroll_end_timer->is_active()) {
+        if (vscrollbar.is_visible() && vscrollbar.value() == vscrollbar.max()) {
+            m_vertical_scroll_end_timer->on_timeout = [&] {
+                if (on_reaching_vertical_end)
+                    on_reaching_vertical_end();
+                m_vertical_scroll_end_timer->stop();
+            };
+            m_vertical_scroll_end_timer->start(50);
+        }
     }
-    if (hscrollbar.is_visible() && hscrollbar.value() == hscrollbar.max()) {
-        if (on_reaching_horizontal_end)
-            on_reaching_horizontal_end();
+    if (!m_horizontal_scroll_end_timer->is_active()) {
+        if (hscrollbar.is_visible() && hscrollbar.value() == hscrollbar.max()) {
+            m_horizontal_scroll_end_timer->on_timeout = [&] {
+                if (on_reaching_horizontal_end)
+                    on_reaching_horizontal_end();
+                m_horizontal_scroll_end_timer->stop();
+            };
+            m_horizontal_scroll_end_timer->start(50);
+        }
     }
 }
 
diff --git a/Userland/Applications/Spreadsheet/SpreadsheetView.h b/Userland/Applications/Spreadsheet/SpreadsheetView.h
index bc07d31bc3..2c27ee2748 100644
--- a/Userland/Applications/Spreadsheet/SpreadsheetView.h
+++ b/Userland/Applications/Spreadsheet/SpreadsheetView.h
@@ -86,6 +86,11 @@ public:
     Function<void()> on_reaching_horizontal_end;
 
 private:
+    InfinitelyScrollableTableView()
+        : m_horizontal_scroll_end_timer(Core::Timer::construct())
+        , m_vertical_scroll_end_timer(Core::Timer::construct())
+    {
+    }
     virtual void did_scroll() override;
     virtual void mousemove_event(GUI::MouseEvent&) override;
     virtual void mouseup_event(GUI::MouseEvent&) override;
@@ -93,6 +98,8 @@ private:
     bool m_should_intercept_drag { false };
     bool m_has_committed_to_dragging { false };
     GUI::ModelIndex m_starting_selection_index;
+    RefPtr<Core::Timer> m_horizontal_scroll_end_timer;
+    RefPtr<Core::Timer> m_vertical_scroll_end_timer;
 };
 
 class SpreadsheetView final : public GUI::Widget {