Synchronize Clipboard with Primary Selection on Linux when copying (#1502)

* Introduce crossPlatformCopy()

It sets the text of the clipboard and also syncs it with the selection
clipboard if it is supported. Such behaviour is pretty common for X11
application on Unix-like Operating Systems.

* Fix clang-format remarks

* Fix weird clang-format config discrepancy between my machine and CI

* Remove clipboard argument from crossPlatformCopy

* Fix clang-format remarks

chatterino.pro

@@ -210,6 +210,7 @@ SOURCES += \
     src/singletons/TooltipPreviewImage.cpp \
     src/singletons/Updates.cpp \
     src/singletons/WindowManager.cpp \
+    src/util/Clipboard.cpp \
     src/util/DebugCount.cpp \
     src/util/FormatTime.cpp \
     src/util/FunctionEventFilter.cpp \
@@ -412,6 +413,7 @@ HEADERS += \
     src/singletons/Updates.hpp \
     src/singletons/WindowManager.hpp \
     src/util/Clamp.hpp \
+    src/util/Clipboard.hpp \
     src/util/CombinePath.hpp \
     src/util/ConcurrentMap.hpp \
     src/util/DebugCount.hpp \

src/util/Clipboard.cpp

@@ -0,0 +1,16 @@
+#include "util/Clipboard.hpp"
+#include <QApplication>
+
+namespace chatterino {
+
+void crossPlatformCopy(const QString &text)
+{
+    auto clipboard = QApplication::clipboard();
+    clipboard->setText(text);
+    if (clipboard->supportsSelection())
+    {
+        clipboard->setText(text, QClipboard::Selection);
+    }
+}
+
+}  // namespace chatterino

src/util/Clipboard.hpp

@@ -0,0 +1,9 @@
+#pragma once
+
+#include <QString>
+
+namespace chatterino {
+
+void crossPlatformCopy(const QString &text);
+
+}  // namespace chatterino

src/widgets/helper/ChannelView.cpp

@@ -28,6 +28,7 @@
 #include "singletons/Theme.hpp"
 #include "singletons/TooltipPreviewImage.hpp"
 #include "singletons/WindowManager.hpp"
+#include "util/Clipboard.hpp"
 #include "util/DistanceBetweenPoints.hpp"
 #include "util/IncognitoBrowser.hpp"
 #include "widgets/Scrollbar.hpp"
@@ -64,9 +65,8 @@ namespace {
             if (!image->isEmpty())
             {
                 copyMenu->addAction(
-                    QString(scale) + "x link", [url = image->url()] {
+                    QString(scale) + "x link",
-                        QApplication::clipboard()->setText(url.string);
+                    [url = image->url()] { crossPlatformCopy(url.string); });
-                    });
                 openMenu->addAction(
                     QString(scale) + "x link", [url = image->url()] {
                         QDesktopServices::openUrl(QUrl(url.string));
@@ -84,9 +84,8 @@ namespace {
             openMenu->addSeparator();
 
             copyMenu->addAction(
-                "Copy " + name + " emote link", [url = emote.homePage] {
+                "Copy " + name + " emote link",
-                    QApplication::clipboard()->setText(url.string);  //
+                [url = emote.homePage] { crossPlatformCopy(url.string); });
-                });
             openMenu->addAction(
                 "Open " + name + " emote link", [url = emote.homePage] {
                     QDesktopServices::openUrl(QUrl(url.string));  //
@@ -124,9 +123,8 @@ ChannelView::ChannelView(BaseWidget *parent)
     });
 
     auto shortcut = new QShortcut(QKeySequence("Ctrl+C"), this);
-    QObject::connect(shortcut, &QShortcut::activated, [this] {
+    QObject::connect(shortcut, &QShortcut::activated,
-        QGuiApplication::clipboard()->setText(this->getSelectedText());
+                     [this] { crossPlatformCopy(this->getSelectedText()); });
-    });
 
     this->clickTimer_ = new QTimer(this);
     this->clickTimer_->setSingleShot(true);
@@ -1552,8 +1550,7 @@ void ChannelView::addContextMenuItems(
             menu->addAction("Open link incognito",
                             [url] { openLinkIncognito(url); });
         }
-        menu->addAction("Copy link",
+        menu->addAction("Copy link", [url] { crossPlatformCopy(url); });
-                        [url] { QApplication::clipboard()->setText(url); });
 
         menu->addSeparator();
     }
@@ -1561,9 +1558,8 @@ void ChannelView::addContextMenuItems(
     // Copy actions
     if (!this->selection_.isEmpty())
     {
-        menu->addAction("Copy selection", [this] {
+        menu->addAction("Copy selection",
-            QGuiApplication::clipboard()->setText(this->getSelectedText());
+                        [this] { crossPlatformCopy(this->getSelectedText()); });
-        });
     }
 
     menu->addAction("Copy message", [layout] {
@@ -1571,14 +1567,14 @@ void ChannelView::addContextMenuItems(
         layout->addSelectionText(copyString, 0, INT_MAX,
                                  CopyMode::OnlyTextAndEmotes);
 
-        QGuiApplication::clipboard()->setText(copyString);
+        crossPlatformCopy(copyString);
     });
 
     menu->addAction("Copy full message", [layout] {
         QString copyString;
         layout->addSelectionText(copyString);
 
-        QGuiApplication::clipboard()->setText(copyString);
+        crossPlatformCopy(copyString);
     });
 
     // Open in new split.

src/widgets/splits/Split.cpp

@@ -10,6 +10,7 @@
 #include "singletons/Settings.hpp"
 #include "singletons/Theme.hpp"
 #include "singletons/WindowManager.hpp"
+#include "util/Clipboard.hpp"
 #include "util/Shortcut.hpp"
 #include "util/StreamLink.hpp"
 #include "widgets/Notebook.hpp"
@@ -659,7 +660,7 @@ void Split::openSubPage()
 
 void Split::copyToClipboard()
 {
-    QApplication::clipboard()->setText(this->view_->getSelectedText());
+    crossPlatformCopy(this->view_->getSelectedText());
 }
 
 void Split::showSearch()