Fix handling of tags containing '&' character

PR #21024.
Closes #20773.

src/gui/torrenttagsdialog.cpp

@@ -1,6 +1,6 @@
 /*
  * Bittorrent Client using Qt and libtorrent.
- * Copyright (C) 2023  Vladimir Golovnev <glassez@yandex.ru>
+ * Copyright (C) 2023-2024  Vladimir Golovnev <glassez@yandex.ru>
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License
@@ -37,6 +37,7 @@
 #include "base/global.h"
 #include "autoexpandabledialog.h"
 #include "flowlayout.h"
+#include "utils.h"
 
 #include "ui_torrenttagsdialog.h"
 
@@ -55,7 +56,7 @@ TorrentTagsDialog::TorrentTagsDialog(const TagSet &initialTags, QWidget *parent)
     auto *tagsLayout = new FlowLayout(m_ui->scrollArea);
     for (const Tag &tag : asConst(initialTags.united(BitTorrent::Session::instance()->tags())))
     {
-        auto *tagWidget = new QCheckBox(tag.toString());
+        auto *tagWidget = new QCheckBox(Utils::Gui::tagToWidgetText(tag));
         if (initialTags.contains(tag))
             tagWidget->setChecked(true);
         tagsLayout->addWidget(tagWidget);
@@ -83,7 +84,7 @@ TagSet TorrentTagsDialog::tags() const
     {
         const auto *tagWidget = static_cast<QCheckBox *>(layout->itemAt(i)->widget());
         if (tagWidget->isChecked())
-            tags.insert(Tag(tagWidget->text()));
+            tags.insert(Utils::Gui::widgetTextToTag(tagWidget->text()));
     }
 
     return tags;
@@ -113,7 +114,7 @@ void TorrentTagsDialog::addNewTag()
         {
             auto *layout = m_ui->scrollArea->layout();
             auto *btn = layout->takeAt(layout->count() - 1);
-            auto *tagWidget = new QCheckBox(tag.toString());
+            auto *tagWidget = new QCheckBox(Utils::Gui::tagToWidgetText(tag));
             tagWidget->setChecked(true);
             layout->addWidget(tagWidget);
             layout->addItem(btn);

src/gui/transferlistwidget.cpp

@@ -1,6 +1,6 @@
 /*
  * Bittorrent Client using Qt and libtorrent.
- * Copyright (C) 2023  Vladimir Golovnev <glassez@yandex.ru>
+ * Copyright (C) 2023-2024  Vladimir Golovnev <glassez@yandex.ru>
  * Copyright (C) 2006  Christophe Dumez <chris@qbittorrent.org>
  *
  * This program is free software; you can redistribute it and/or
@@ -1191,7 +1191,7 @@ void TransferListWidget::displayListMenu()
     const TagSet tags = BitTorrent::Session::instance()->tags();
     for (const Tag &tag : asConst(tags))
     {
-        auto *action = new TriStateAction(tag.toString(), tagsMenu);
+        auto *action = new TriStateAction(Utils::Gui::tagToWidgetText(tag), tagsMenu);
         action->setCloseOnInteraction(false);
 
         const Qt::CheckState initialState = tagsInAll.contains(tag) ? Qt::Checked

src/gui/utils.cpp

@@ -1,5 +1,6 @@
 /*
  * Bittorrent Client using Qt and libtorrent.
+ * Copyright (C) 2024  Vladimir Golovnev <glassez@yandex.ru>
  * Copyright (C) 2017  Mike Tzou
  *
  * This program is free software; you can redistribute it and/or
@@ -54,6 +55,7 @@
 
 #include "base/global.h"
 #include "base/path.h"
+#include "base/tag.h"
 #include "base/utils/fs.h"
 #include "base/utils/version.h"
 
@@ -216,3 +218,29 @@ void Utils::Gui::openFolderSelect(const Path &path)
     openPath(path.parentPath());
 #endif
 }
+
+QString Utils::Gui::tagToWidgetText(const Tag &tag)
+{
+    return tag.toString().replace(u'&', u"&&"_s);
+}
+
+Tag Utils::Gui::widgetTextToTag(const QString &text)
+{
+    // replace pairs of '&' with single '&' and remove non-paired occurrences of '&'
+    QString cleanedText;
+    cleanedText.reserve(text.size());
+    bool amp = false;
+    for (const QChar c : text)
+    {
+        if (c == u'&')
+        {
+            amp = !amp;
+            if (amp)
+                continue;
+        }
+
+        cleanedText.append(c);
+    }
+
+    return Tag(cleanedText);
+}

src/gui/utils.h

@@ -1,5 +1,6 @@
 /*
  * Bittorrent Client using Qt and libtorrent.
+ * Copyright (C) 2024  Vladimir Golovnev <glassez@yandex.ru>
  * Copyright (C) 2017  Mike Tzou
  *
  * This program is free software; you can redistribute it and/or
@@ -34,8 +35,11 @@ class QIcon;
 class QPixmap;
 class QPoint;
 class QSize;
+class QString;
 class QWidget;
 
+class Tag;
+
 namespace Utils::Gui
 {
     bool isDarkTheme();
@@ -51,4 +55,7 @@ namespace Utils::Gui
 
     void openPath(const Path &path);
     void openFolderSelect(const Path &path);
+
+    QString tagToWidgetText(const Tag &tag);
+    Tag widgetTextToTag(const QString &text);
 }