From d65ff871487bb39d26e7af765ce3214f034be82a Mon Sep 17 00:00:00 2001
From: Chocobo1 <Chocobo1@users.noreply.github.com>
Date: Sun, 4 Oct 2015 20:48:43 +0800
Subject: [PATCH 1/5] Replace `naturalSort()` with `naturalCompare()`.

---
 src/base/utils/string.cpp              | 79 +++++---------------------
 src/base/utils/string.h                |  6 +-
 src/gui/addnewtorrentdialog.cpp        |  2 +-
 src/gui/properties/peerlistsortmodel.h | 23 +++-----
 src/gui/rss/automatedrssdownloader.cpp |  2 +-
 src/gui/search/searchsortmodel.cpp     | 21 +++----
 src/gui/torrentcontentfiltermodel.cpp  | 28 ++++-----
 src/gui/transferlistfilterswidget.cpp  | 28 ++++-----
 src/gui/transferlistsortmodel.cpp      | 42 ++++++++------
 9 files changed, 82 insertions(+), 149 deletions(-)

diff --git a/src/base/utils/string.cpp b/src/base/utils/string.cpp
index 046b33d7e..7d43b6284 100644
--- a/src/base/utils/string.cpp
+++ b/src/base/utils/string.cpp
@@ -44,68 +44,6 @@ std::string Utils::String::toStdString(const QString &str)
     return std::string(utf8.constData(), utf8.length());
 }
 
-// uses lessThan comparison
-bool Utils::String::naturalSort(const QString &left, const QString &right, bool &result)
-{
-    // Return value indicates if functions was successful
-    // result argument will contain actual comparison result if function was successful
-    int posL = 0;
-    int posR = 0;
-    do {
-        forever {
-            if (posL == left.size() || posR == right.size())
-                return false; // No data
-
-            QChar leftChar = left.at(posL);
-            QChar rightChar = right.at(posR);
-            bool leftCharIsDigit = leftChar.isDigit();
-            bool rightCharIsDigit = rightChar.isDigit();
-            if (leftCharIsDigit != rightCharIsDigit)
-                return false; // Digit positions mismatch
-
-            if (leftCharIsDigit)
-                break; // Both are digit, break this loop and compare numbers
-
-            if (leftChar != rightChar)
-                return false; // Strings' subsets before digit do not match
-
-            ++posL;
-            ++posR;
-        }
-
-        QString temp;
-        while (posL < left.size()) {
-            if (left.at(posL).isDigit())
-                temp += left.at(posL);
-            else
-                break;
-            posL++;
-        }
-        int numL = temp.toInt();
-        temp.clear();
-
-        while (posR < right.size()) {
-            if (right.at(posR).isDigit())
-                temp += right.at(posR);
-            else
-                break;
-            posR++;
-        }
-        int numR = temp.toInt();
-
-        if (numL != numR) {
-            result = (numL < numR);
-            return true;
-        }
-
-        // Strings + digits do match and we haven't hit string end
-        // Do another round
-
-    } while (true);
-
-    return false;
-}
-
 Utils::String::NaturalCompare::NaturalCompare()
 {
 #if (QT_VERSION >= QT_VERSION_CHECK(5, 2, 0))
@@ -119,23 +57,25 @@ Utils::String::NaturalCompare::NaturalCompare()
 #endif
 }
 
-bool Utils::String::NaturalCompare::operator()(const QString &l, const QString &r)
+bool Utils::String::NaturalCompare::operator()(const QString &left, const QString &right)
 {
+    // case-insensitive comparison
 #if (QT_VERSION >= QT_VERSION_CHECK(5, 2, 0))
 #if defined(Q_OS_WIN)
     // Without ICU library, QCollator doesn't support `setNumericMode(true)` on OS older than Win7
     if(QSysInfo::windowsVersion() < QSysInfo::WV_WINDOWS7)
-        return lessThan(l, r);
+        return lessThan(left, right);
 #endif
-    return (m_collator.compare(l, r) < 0);
+    return (m_collator.compare(left, right) < 0);
 #else
-    return lessThan(l, r);
+    return lessThan(left, right);
 #endif
 }
 
 bool Utils::String::NaturalCompare::lessThan(const QString &left, const QString &right)
 {
     // Return value `false` indicates `right` should go before `left`, otherwise, after
+    // case-insensitive comparison
     int posL = 0;
     int posR = 0;
     while (true) {
@@ -183,6 +123,13 @@ bool Utils::String::NaturalCompare::lessThan(const QString &left, const QString
     return false;
 }
 
+bool Utils::String::naturalCompare(const QString &left, const QString &right)
+{
+    // provide a single `NaturalCompare` instance for easy use
+    static NaturalCompare nCmp;  // this is thread-safe in C++11 (stated in spec 6.7.4)
+    return nCmp(left, right);
+}
+
 // to send numbers instead of strings with suffixes
 QString Utils::String::fromDouble(double n, int precision)
 {
diff --git a/src/base/utils/string.h b/src/base/utils/string.h
index 36b34e979..e379beadd 100644
--- a/src/base/utils/string.h
+++ b/src/base/utils/string.h
@@ -51,19 +51,19 @@ namespace Utils
         // Taken from https://crackstation.net/hashing-security.htm
         bool slowEquals(const QByteArray &a, const QByteArray &b);
 
-        bool naturalSort(const QString &left, const QString &right, bool &result);
-
         class NaturalCompare
         {
         public:
             NaturalCompare();
-            bool operator()(const QString &l, const QString &r);
+            bool operator()(const QString &left, const QString &right);
             bool lessThan(const QString &left, const QString &right);
 #if (QT_VERSION >= QT_VERSION_CHECK(5, 2, 0))
         private:
             QCollator m_collator;
 #endif
         };
+
+        bool naturalCompare(const QString &left, const QString &right);
     }
 }
 
diff --git a/src/gui/addnewtorrentdialog.cpp b/src/gui/addnewtorrentdialog.cpp
index fa441c727..3511ef73f 100644
--- a/src/gui/addnewtorrentdialog.cpp
+++ b/src/gui/addnewtorrentdialog.cpp
@@ -96,7 +96,7 @@ AddNewTorrentDialog::AddNewTorrentDialog(QWidget *parent)
 
     // Load categories
     QStringList categories = session->categories();
-    std::sort(categories.begin(), categories.end(), Utils::String::NaturalCompare());
+    std::sort(categories.begin(), categories.end(), Utils::String::naturalCompare);
     QString defaultCategory = settings()->loadValue(KEY_DEFAULTCATEGORY).toString();
 
     if (!defaultCategory.isEmpty())
diff --git a/src/gui/properties/peerlistsortmodel.h b/src/gui/properties/peerlistsortmodel.h
index d37a9ccd1..ac298a3da 100644
--- a/src/gui/properties/peerlistsortmodel.h
+++ b/src/gui/properties/peerlistsortmodel.h
@@ -43,21 +43,16 @@ public:
 
 protected:
   bool lessThan(const QModelIndex &left, const QModelIndex &right) const {
-    if (sortColumn() == PeerListDelegate::IP || sortColumn() == PeerListDelegate::CLIENT) {
-      QVariant vL = sourceModel()->data(left);
-      QVariant vR = sourceModel()->data(right);
-      if (!(vL.isValid() && vR.isValid()))
-        return QSortFilterProxyModel::lessThan(left, right);
-      Q_ASSERT(vL.isValid());
-      Q_ASSERT(vR.isValid());
+  switch (sortColumn()) {
+  case PeerListDelegate::IP:
+  case PeerListDelegate::CLIENT: {
+    QString vL = left.data().toString();
+    QString vR = right.data().toString();
+    return Utils::String::naturalCompare(vL, vR);
+  }
+  };
 
-      bool res = false;
-      if (Utils::String::naturalSort(vL.toString(), vR.toString(), res))
-        return res;
-
-      return QSortFilterProxyModel::lessThan(left, right);
-    }
-    return QSortFilterProxyModel::lessThan(left, right);
+  return QSortFilterProxyModel::lessThan(left, right);
   }
 };
 
diff --git a/src/gui/rss/automatedrssdownloader.cpp b/src/gui/rss/automatedrssdownloader.cpp
index 7721462a7..744229710 100644
--- a/src/gui/rss/automatedrssdownloader.cpp
+++ b/src/gui/rss/automatedrssdownloader.cpp
@@ -314,7 +314,7 @@ void AutomatedRssDownloader::initCategoryCombobox()
 {
   // Load torrent categories
   QStringList categories = BitTorrent::Session::instance()->categories();
-  std::sort(categories.begin(), categories.end(), Utils::String::NaturalCompare());
+  std::sort(categories.begin(), categories.end(), Utils::String::naturalCompare);
   ui->comboCategory->addItems(categories);
 }
 
diff --git a/src/gui/search/searchsortmodel.cpp b/src/gui/search/searchsortmodel.cpp
index 22cc20fd6..0052029eb 100644
--- a/src/gui/search/searchsortmodel.cpp
+++ b/src/gui/search/searchsortmodel.cpp
@@ -107,20 +107,17 @@ qint64 SearchSortModel::maxSize() const
 
 bool SearchSortModel::lessThan(const QModelIndex &left, const QModelIndex &right) const
 {
-    if ((sortColumn() == NAME) || (sortColumn() == ENGINE_URL)) {
-        QVariant vL = sourceModel()->data(left);
-        QVariant vR = sourceModel()->data(right);
-        if (!(vL.isValid() && vR.isValid()))
-            return base::lessThan(left, right);
-        Q_ASSERT(vL.isValid());
-        Q_ASSERT(vR.isValid());
-
-        bool res = false;
-        if (Utils::String::naturalSort(vL.toString(), vR.toString(), res))
-            return res;
+    switch (sortColumn()) {
+    case NAME:
+    case ENGINE_URL: {
+        QString vL = left.data().toString();
+        QString vR = right.data().toString();
+        return Utils::String::naturalCompare(vL, vR);
     }
 
-    return base::lessThan(left, right);
+    default:
+        return base::lessThan(left, right);
+    };
 }
 
 bool SearchSortModel::filterAcceptsRow(int sourceRow, const QModelIndex &sourceParent) const
diff --git a/src/gui/torrentcontentfiltermodel.cpp b/src/gui/torrentcontentfiltermodel.cpp
index ac0a0edf5..fb4d849b1 100644
--- a/src/gui/torrentcontentfiltermodel.cpp
+++ b/src/gui/torrentcontentfiltermodel.cpp
@@ -82,28 +82,22 @@ bool TorrentContentFilterModel::filterAcceptsRow(int source_row, const QModelInd
 }
 
 bool TorrentContentFilterModel::lessThan(const QModelIndex &left, const QModelIndex &right) const {
-  if (sortColumn() == NAME) {
-    QVariant vL = sourceModel()->data(left);
-    QVariant vR = sourceModel()->data(right);
-    if (!(vL.isValid() && vR.isValid()))
-      return QSortFilterProxyModel::lessThan(left, right);
-    Q_ASSERT(vL.isValid());
-    Q_ASSERT(vR.isValid());
+  switch (sortColumn()) {
+  case NAME: {  // PropColumn::NAME
+    QString vL = left.data().toString();
+    QString vR = right.data().toString();
+    TorrentContentModelItem::ItemType leftType = m_model->itemType(m_model->index(left.row(), 0, left.parent()));
+    TorrentContentModelItem::ItemType rightType = m_model->itemType(m_model->index(right.row(), 0, right.parent()));
 
-    TorrentContentModelItem::ItemType leftType, rightType;
-    leftType = m_model->itemType(m_model->index(left.row(), 0, left.parent()));
-    rightType = m_model->itemType(m_model->index(right.row(), 0, right.parent()));
-    if (leftType == rightType) {
-      bool res = false;
-      if (Utils::String::naturalSort(vL.toString(), vR.toString(), res))
-        return res;
-      return QSortFilterProxyModel::lessThan(left, right);
-    }
+    if (leftType == rightType)
+      return Utils::String::naturalCompare(vL, vR);
     else if (leftType == TorrentContentModelItem::FolderType && sortOrder() == Qt::AscendingOrder)
       return true;
     else
-       return false;
+      return false;
   }
+  };
+
   return QSortFilterProxyModel::lessThan(left, right);
 }
 
diff --git a/src/gui/transferlistfilterswidget.cpp b/src/gui/transferlistfilterswidget.cpp
index c83f48b87..a2da34141 100644
--- a/src/gui/transferlistfilterswidget.cpp
+++ b/src/gui/transferlistfilterswidget.cpp
@@ -237,17 +237,14 @@ void CategoryFiltersList::addItem(const QString &category, bool hasTorrent)
     if (exists) return;
 
     Q_ASSERT(count() >= 2);
+    int insPos = count();
     for (int i = 2; i < count(); ++i) {
-        bool less = false;
-        if (!(Utils::String::naturalSort(category, item(i)->text(), less)))
-            less = (category.localeAwareCompare(item(i)->text()) < 0);
-        if (less) {
-            insertItem(i, categoryItem);
-            updateGeometry();
-            return;
+        if (Utils::String::naturalCompare(category, item(i)->text())) {
+            insPos = i;
+            break;
         }
     }
-    QListWidget::addItem(categoryItem);
+    QListWidget::insertItem(insPos, categoryItem);
     updateGeometry();
 }
 
@@ -512,17 +509,14 @@ void TrackerFiltersList::addItem(const QString &tracker, const QString &hash)
     }
 
     Q_ASSERT(count() >= 4);
-    for (int i = 4; i<count(); ++i) {
-        bool less = false;
-        if (!(Utils::String::naturalSort(host, item(i)->text(), less)))
-            less = (host.localeAwareCompare(item(i)->text()) < 0);
-        if (less) {
-            insertItem(i, trackerItem);
-            updateGeometry();
-            return;
+    int insPos = count();
+    for (int i = 4; i < count(); ++i) {
+        if (Utils::String::naturalCompare(host, item(i)->text())) {
+            insPos = i;
+            break;
         }
     }
-    QListWidget::addItem(trackerItem);
+    QListWidget::insertItem(insPos, trackerItem);
     updateGeometry();
 }
 
diff --git a/src/gui/transferlistsortmodel.cpp b/src/gui/transferlistsortmodel.cpp
index c69253666..06eeed220 100644
--- a/src/gui/transferlistsortmodel.cpp
+++ b/src/gui/transferlistsortmodel.cpp
@@ -73,21 +73,19 @@ void TransferListSortModel::disableTrackerFilter()
 
 bool TransferListSortModel::lessThan(const QModelIndex &left, const QModelIndex &right) const
 {
-    const int column  = sortColumn();
-
-    if (column == TorrentModel::TR_NAME) {
+    switch (sortColumn()) {
+    case TorrentModel::TR_NAME: {
         QVariant vL = left.data();
         QVariant vR = right.data();
         if (!vL.isValid() || !vR.isValid() || (vL == vR))
             return lowerPositionThan(left, right);
 
-        bool res = false;
-        if (Utils::String::naturalSort(vL.toString(), vR.toString(), res))
-            return res;
-
-        return QSortFilterProxyModel::lessThan(left, right);
+        return Utils::String::naturalCompare(vL.toString(), vR.toString());
     }
-    else if (column == TorrentModel::TR_ADD_DATE || column == TorrentModel::TR_SEED_DATE || column == TorrentModel::TR_SEEN_COMPLETE_DATE) {
+
+    case TorrentModel::TR_ADD_DATE:
+    case TorrentModel::TR_SEED_DATE:
+    case TorrentModel::TR_SEEN_COMPLETE_DATE: {
         QDateTime vL = left.data().toDateTime();
         QDateTime vR = right.data().toDateTime();
 
@@ -97,10 +95,13 @@ bool TransferListSortModel::lessThan(const QModelIndex &left, const QModelIndex
 
         return vL < vR;
     }
-    else if (column == TorrentModel::TR_PRIORITY) {
+
+    case TorrentModel::TR_PRIORITY: {
         return lowerPositionThan(left, right);
     }
-    else if (column == TorrentModel::TR_PEERS || column == TorrentModel::TR_SEEDS) {
+
+    case TorrentModel::TR_SEEDS:
+    case TorrentModel::TR_PEERS: {
         int left_active = left.data().toInt();
         int left_total = left.data(Qt::UserRole).toInt();
         int right_active = right.data().toInt();
@@ -116,7 +117,8 @@ bool TransferListSortModel::lessThan(const QModelIndex &left, const QModelIndex
             return (left_active < right_active);
         }
     }
-    else if (column == TorrentModel::TR_ETA) {
+
+    case TorrentModel::TR_ETA: {
         TorrentModel *model = qobject_cast<TorrentModel *>(sourceModel());
         const int prioL = model->data(model->index(left.row(), TorrentModel::TR_PRIORITY)).toInt();
         const int prioR = model->data(model->index(right.row(), TorrentModel::TR_PRIORITY)).toInt();
@@ -164,7 +166,8 @@ bool TransferListSortModel::lessThan(const QModelIndex &left, const QModelIndex
             return !invalidL;
         }
     }
-    else if (column == TorrentModel::TR_LAST_ACTIVITY) {
+
+    case TorrentModel::TR_LAST_ACTIVITY: {
         const qlonglong vL = left.data().toLongLong();
         const qlonglong vR = right.data().toLongLong();
 
@@ -173,7 +176,8 @@ bool TransferListSortModel::lessThan(const QModelIndex &left, const QModelIndex
 
         return vL < vR;
     }
-    else if (column == TorrentModel::TR_RATIO_LIMIT) {
+
+    case TorrentModel::TR_RATIO_LIMIT: {
         const qreal vL = left.data().toDouble();
         const qreal vR = right.data().toDouble();
 
@@ -183,10 +187,12 @@ bool TransferListSortModel::lessThan(const QModelIndex &left, const QModelIndex
         return vL < vR;
     }
 
-    if (left.data() == right.data())
-        return lowerPositionThan(left, right);
-
-    return QSortFilterProxyModel::lessThan(left, right);
+    default: {
+        if (left.data() == right.data())
+            return lowerPositionThan(left, right);
+        return QSortFilterProxyModel::lessThan(left, right);
+    }
+    };
 }
 
 bool TransferListSortModel::lowerPositionThan(const QModelIndex &left, const QModelIndex &right) const

From c3bde7c910fb3d6d1600150e7b576a1d7bd40339 Mon Sep 17 00:00:00 2001
From: Chocobo1 <Chocobo1@users.noreply.github.com>
Date: Sun, 11 Oct 2015 21:15:41 +0800
Subject: [PATCH 2/5] Sort labels with `naturalCompare()`. Closes #3919.

---
 src/gui/transferlistwidget.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/gui/transferlistwidget.cpp b/src/gui/transferlistwidget.cpp
index b2eaa7caf..d147f8c6c 100644
--- a/src/gui/transferlistwidget.cpp
+++ b/src/gui/transferlistwidget.cpp
@@ -769,7 +769,7 @@ void TransferListWidget::displayListMenu(const QPoint&)
         listMenu.addAction(&actionRename);
     // Category Menu
     QStringList categories = BitTorrent::Session::instance()->categories();
-    std::sort(categories.begin(), categories.end(), Utils::String::NaturalCompare());
+    std::sort(categories.begin(), categories.end(), Utils::String::naturalCompare);
     QList<QAction*> categoryActions;
     QMenu *categoryMenu = listMenu.addMenu(GuiIconProvider::instance()->getIcon("view-categories"), tr("Category"));
     categoryActions << categoryMenu->addAction(GuiIconProvider::instance()->getIcon("list-add"), tr("New...", "New category..."));

From 626a224382414586a9df63f1d0c81a4168ae4c6c Mon Sep 17 00:00:00 2001
From: Chocobo1 <Chocobo1@users.noreply.github.com>
Date: Tue, 12 Apr 2016 14:08:04 +0800
Subject: [PATCH 3/5] Minor code formatting

---
 src/base/utils/string.cpp | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/base/utils/string.cpp b/src/base/utils/string.cpp
index 7d43b6284..d01799fe0 100644
--- a/src/base/utils/string.cpp
+++ b/src/base/utils/string.cpp
@@ -49,7 +49,7 @@ Utils::String::NaturalCompare::NaturalCompare()
 #if (QT_VERSION >= QT_VERSION_CHECK(5, 2, 0))
 #if defined(Q_OS_WIN)
     // Without ICU library, QCollator doesn't support `setNumericMode(true)` on OS older than Win7
-    if(QSysInfo::windowsVersion() < QSysInfo::WV_WINDOWS7)
+    if (QSysInfo::windowsVersion() < QSysInfo::WV_WINDOWS7)
         return;
 #endif
     m_collator.setNumericMode(true);
@@ -63,7 +63,7 @@ bool Utils::String::NaturalCompare::operator()(const QString &left, const QStrin
 #if (QT_VERSION >= QT_VERSION_CHECK(5, 2, 0))
 #if defined(Q_OS_WIN)
     // Without ICU library, QCollator doesn't support `setNumericMode(true)` on OS older than Win7
-    if(QSysInfo::windowsVersion() < QSysInfo::WV_WINDOWS7)
+    if (QSysInfo::windowsVersion() < QSysInfo::WV_WINDOWS7)
         return lessThan(left, right);
 #endif
     return (m_collator.compare(left, right) < 0);
@@ -80,7 +80,7 @@ bool Utils::String::NaturalCompare::lessThan(const QString &left, const QString
     int posR = 0;
     while (true) {
         while (true) {
-            if (posL == left.size() || posR == right.size())
+            if ((posL == left.size()) || (posR == right.size()))
                 return (left.size() < right.size());  // when a shorter string is another string's prefix, shorter string place before longer string
 
             QChar leftChar = left[posL].toLower();

From d25430f377c2a68011155e9fe41a0d63606e82d8 Mon Sep 17 00:00:00 2001
From: Chocobo1 <Chocobo1@users.noreply.github.com>
Date: Mon, 18 Apr 2016 14:18:30 +0800
Subject: [PATCH 4/5] Cleanup headers

Move `class NaturalCompare` to .cpp file
---
 src/base/utils/string.cpp | 50 ++++++++++++++++++++++++++-------------
 src/base/utils/string.h   | 18 +-------------
 2 files changed, 35 insertions(+), 33 deletions(-)

diff --git a/src/base/utils/string.cpp b/src/base/utils/string.cpp
index d01799fe0..ccd35940c 100644
--- a/src/base/utils/string.cpp
+++ b/src/base/utils/string.cpp
@@ -27,24 +27,31 @@
  * exception statement from your version.
  */
 
-#include <QByteArray>
-#include <QString>
-#include <QLocale>
-#include <cmath>
 #include "string.h"
 
-QString Utils::String::fromStdString(const std::string &str)
-{
-    return QString::fromUtf8(str.c_str());
-}
+#include <cmath>
 
-std::string Utils::String::toStdString(const QString &str)
-{
-    QByteArray utf8 = str.toUtf8();
-    return std::string(utf8.constData(), utf8.length());
-}
+#include <QByteArray>
+#include <QtGlobal>
+#include <QLocale>
+#if (QT_VERSION >= QT_VERSION_CHECK(5, 2, 0))
+#include <QCollator>
+#endif
 
-Utils::String::NaturalCompare::NaturalCompare()
+class NaturalCompare
+{
+public:
+    NaturalCompare();
+    bool operator()(const QString &left, const QString &right);
+    bool lessThan(const QString &left, const QString &right);
+
+private:
+#if (QT_VERSION >= QT_VERSION_CHECK(5, 2, 0))
+    QCollator m_collator;
+#endif
+};
+
+NaturalCompare::NaturalCompare()
 {
 #if (QT_VERSION >= QT_VERSION_CHECK(5, 2, 0))
 #if defined(Q_OS_WIN)
@@ -57,7 +64,7 @@ Utils::String::NaturalCompare::NaturalCompare()
 #endif
 }
 
-bool Utils::String::NaturalCompare::operator()(const QString &left, const QString &right)
+bool NaturalCompare::operator()(const QString &left, const QString &right)
 {
     // case-insensitive comparison
 #if (QT_VERSION >= QT_VERSION_CHECK(5, 2, 0))
@@ -72,7 +79,7 @@ bool Utils::String::NaturalCompare::operator()(const QString &left, const QStrin
 #endif
 }
 
-bool Utils::String::NaturalCompare::lessThan(const QString &left, const QString &right)
+bool NaturalCompare::lessThan(const QString &left, const QString &right)
 {
     // Return value `false` indicates `right` should go before `left`, otherwise, after
     // case-insensitive comparison
@@ -123,6 +130,17 @@ bool Utils::String::NaturalCompare::lessThan(const QString &left, const QString
     return false;
 }
 
+QString Utils::String::fromStdString(const std::string &str)
+{
+    return QString::fromUtf8(str.c_str());
+}
+
+std::string Utils::String::toStdString(const QString &str)
+{
+    QByteArray utf8 = str.toUtf8();
+    return std::string(utf8.constData(), utf8.length());
+}
+
 bool Utils::String::naturalCompare(const QString &left, const QString &right)
 {
     // provide a single `NaturalCompare` instance for easy use
diff --git a/src/base/utils/string.h b/src/base/utils/string.h
index e379beadd..9a3c66843 100644
--- a/src/base/utils/string.h
+++ b/src/base/utils/string.h
@@ -31,13 +31,9 @@
 #define UTILS_STRING_H
 
 #include <string>
-#include <QtGlobal>
-#if (QT_VERSION >= QT_VERSION_CHECK(5, 2, 0))
-#include <QCollator>
-#endif
 
-class QString;
 class QByteArray;
+class QString;
 
 namespace Utils
 {
@@ -51,18 +47,6 @@ namespace Utils
         // Taken from https://crackstation.net/hashing-security.htm
         bool slowEquals(const QByteArray &a, const QByteArray &b);
 
-        class NaturalCompare
-        {
-        public:
-            NaturalCompare();
-            bool operator()(const QString &left, const QString &right);
-            bool lessThan(const QString &left, const QString &right);
-#if (QT_VERSION >= QT_VERSION_CHECK(5, 2, 0))
-        private:
-            QCollator m_collator;
-#endif
-        };
-
         bool naturalCompare(const QString &left, const QString &right);
     }
 }

From 5906a4a2dea9df48f0a03bc8cbb03c312322f489 Mon Sep 17 00:00:00 2001
From: Chocobo1 <Chocobo1@users.noreply.github.com>
Date: Wed, 4 May 2016 17:15:58 +0800
Subject: [PATCH 5/5] Add case-sensitive & case-insensitive natural sort helper
 function

Fix helper function not being thread-safe
Use QBT_USES_QT5 define
---
 src/base/utils/string.cpp              | 191 ++++++++++++++-----------
 src/base/utils/string.h                |   3 +-
 src/gui/addnewtorrentdialog.cpp        |   2 +-
 src/gui/properties/peerlistsortmodel.h |   2 +-
 src/gui/rss/automatedrssdownloader.cpp |   2 +-
 src/gui/search/searchsortmodel.cpp     |   2 +-
 src/gui/torrentcontentfiltermodel.cpp  |   2 +-
 src/gui/transferlistfilterswidget.cpp  |   4 +-
 src/gui/transferlistsortmodel.cpp      |   2 +-
 src/gui/transferlistwidget.cpp         |   2 +-
 10 files changed, 118 insertions(+), 94 deletions(-)

diff --git a/src/base/utils/string.cpp b/src/base/utils/string.cpp
index ccd35940c..37a00713e 100644
--- a/src/base/utils/string.cpp
+++ b/src/base/utils/string.cpp
@@ -34,100 +34,130 @@
 #include <QByteArray>
 #include <QtGlobal>
 #include <QLocale>
-#if (QT_VERSION >= QT_VERSION_CHECK(5, 2, 0))
+#ifdef QBT_USES_QT5
 #include <QCollator>
 #endif
-
-class NaturalCompare
-{
-public:
-    NaturalCompare();
-    bool operator()(const QString &left, const QString &right);
-    bool lessThan(const QString &left, const QString &right);
-
-private:
-#if (QT_VERSION >= QT_VERSION_CHECK(5, 2, 0))
-    QCollator m_collator;
+#ifdef Q_OS_MAC
+#include <QThreadStorage>
 #endif
-};
 
-NaturalCompare::NaturalCompare()
+namespace
 {
-#if (QT_VERSION >= QT_VERSION_CHECK(5, 2, 0))
+    class NaturalCompare
+    {
+    public:
+        explicit NaturalCompare(const bool caseSensitive = true)
+            : m_caseSensitive(caseSensitive)
+        {
+#ifdef QBT_USES_QT5
 #if defined(Q_OS_WIN)
-    // Without ICU library, QCollator doesn't support `setNumericMode(true)` on OS older than Win7
-    if (QSysInfo::windowsVersion() < QSysInfo::WV_WINDOWS7)
-        return;
+            // Without ICU library, QCollator doesn't support `setNumericMode(true)` on OS older than Win7
+            if (QSysInfo::windowsVersion() < QSysInfo::WV_WINDOWS7)
+                return;
 #endif
-    m_collator.setNumericMode(true);
-    m_collator.setCaseSensitivity(Qt::CaseInsensitive);
+            m_collator.setNumericMode(true);
+            m_collator.setCaseSensitivity(caseSensitive ? Qt::CaseSensitive : Qt::CaseInsensitive);
 #endif
-}
-
-bool NaturalCompare::operator()(const QString &left, const QString &right)
-{
-    // case-insensitive comparison
-#if (QT_VERSION >= QT_VERSION_CHECK(5, 2, 0))
-#if defined(Q_OS_WIN)
-    // Without ICU library, QCollator doesn't support `setNumericMode(true)` on OS older than Win7
-    if (QSysInfo::windowsVersion() < QSysInfo::WV_WINDOWS7)
-        return lessThan(left, right);
-#endif
-    return (m_collator.compare(left, right) < 0);
-#else
-    return lessThan(left, right);
-#endif
-}
-
-bool NaturalCompare::lessThan(const QString &left, const QString &right)
-{
-    // Return value `false` indicates `right` should go before `left`, otherwise, after
-    // case-insensitive comparison
-    int posL = 0;
-    int posR = 0;
-    while (true) {
-        while (true) {
-            if ((posL == left.size()) || (posR == right.size()))
-                return (left.size() < right.size());  // when a shorter string is another string's prefix, shorter string place before longer string
-
-            QChar leftChar = left[posL].toLower();
-            QChar rightChar = right[posR].toLower();
-            if (leftChar == rightChar)
-                ;  // compare next character
-            else if (leftChar.isDigit() && rightChar.isDigit())
-                break; // Both are digits, break this loop and compare numbers
-            else
-                return leftChar < rightChar;
-
-            ++posL;
-            ++posR;
         }
 
-        int startL = posL;
-        while ((posL < left.size()) && left[posL].isDigit())
-            ++posL;
-#if QT_VERSION >= QT_VERSION_CHECK(5, 1, 0)
-        int numL = left.midRef(startL, posL - startL).toInt();
+        bool operator()(const QString &left, const QString &right) const
+        {
+#ifdef QBT_USES_QT5
+#if defined(Q_OS_WIN)
+            // Without ICU library, QCollator doesn't support `setNumericMode(true)` on OS older than Win7
+            if (QSysInfo::windowsVersion() < QSysInfo::WV_WINDOWS7)
+                return lessThan(left, right);
+#endif
+            return (m_collator.compare(left, right) < 0);
 #else
-        int numL = left.mid(startL, posL - startL).toInt();
+            return lessThan(left, right);
+#endif
+        }
+
+        bool lessThan(const QString &left, const QString &right) const
+        {
+            // Return value `false` indicates `right` should go before `left`, otherwise, after
+            int posL = 0;
+            int posR = 0;
+            while (true) {
+                while (true) {
+                    if ((posL == left.size()) || (posR == right.size()))
+                        return (left.size() < right.size());  // when a shorter string is another string's prefix, shorter string place before longer string
+
+                    QChar leftChar = m_caseSensitive ? left[posL] : left[posL].toLower();
+                    QChar rightChar = m_caseSensitive ? right[posR] : right[posR].toLower();
+                    if (leftChar == rightChar)
+                        ;  // compare next character
+                    else if (leftChar.isDigit() && rightChar.isDigit())
+                        break; // Both are digits, break this loop and compare numbers
+                    else
+                        return leftChar < rightChar;
+
+                    ++posL;
+                    ++posR;
+                }
+
+                int startL = posL;
+                while ((posL < left.size()) && left[posL].isDigit())
+                    ++posL;
+#ifdef QBT_USES_QT5
+                int numL = left.midRef(startL, posL - startL).toInt();
+#else
+                int numL = left.mid(startL, posL - startL).toInt();
 #endif
 
-        int startR = posR;
-        while ((posR < right.size()) && right[posR].isDigit())
-            ++posR;
-#if QT_VERSION >= QT_VERSION_CHECK(5, 1, 0)
-        int numR = right.midRef(startR, posR - startR).toInt();
+                int startR = posR;
+                while ((posR < right.size()) && right[posR].isDigit())
+                    ++posR;
+#ifdef QBT_USES_QT5
+                int numR = right.midRef(startR, posR - startR).toInt();
 #else
-        int numR = right.mid(startR, posR - startR).toInt();
+                int numR = right.mid(startR, posR - startR).toInt();
 #endif
 
-        if (numL != numR)
-            return (numL < numR);
+                if (numL != numR)
+                    return (numL < numR);
 
-        // Strings + digits do match and we haven't hit string end
-        // Do another round
-    }
-    return false;
+                // Strings + digits do match and we haven't hit string end
+                // Do another round
+            }
+            return false;
+        }
+
+    private:
+#ifdef QBT_USES_QT5
+        QCollator m_collator;
+#endif
+        const bool m_caseSensitive;
+    };
+}
+
+bool Utils::String::naturalCompareCaseSensitive(const QString &left, const QString &right)
+{
+    // provide a single `NaturalCompare` instance for easy use
+    // https://doc.qt.io/qt-5/threads-reentrancy.html
+#ifdef Q_OS_MAC  // workaround for Apple xcode: https://stackoverflow.com/a/29929949
+    static QThreadStorage<NaturalCompare> nCmp;
+    if (!nCmp.hasLocalData()) nCmp.setLocalData(NaturalCompare(true));
+    return (nCmp.localData())(left, right);
+#else
+    thread_local NaturalCompare nCmp(true);
+    return nCmp(left, right);
+#endif
+}
+
+bool Utils::String::naturalCompareCaseInsensitive(const QString &left, const QString &right)
+{
+    // provide a single `NaturalCompare` instance for easy use
+    // https://doc.qt.io/qt-5/threads-reentrancy.html
+#ifdef Q_OS_MAC  // workaround for Apple xcode: https://stackoverflow.com/a/29929949
+    static QThreadStorage<NaturalCompare> nCmp;
+    if (!nCmp.hasLocalData()) nCmp.setLocalData(NaturalCompare(false));
+    return (nCmp.localData())(left, right);
+#else
+    thread_local NaturalCompare nCmp(false);
+    return nCmp(left, right);
+#endif
 }
 
 QString Utils::String::fromStdString(const std::string &str)
@@ -141,13 +171,6 @@ std::string Utils::String::toStdString(const QString &str)
     return std::string(utf8.constData(), utf8.length());
 }
 
-bool Utils::String::naturalCompare(const QString &left, const QString &right)
-{
-    // provide a single `NaturalCompare` instance for easy use
-    static NaturalCompare nCmp;  // this is thread-safe in C++11 (stated in spec 6.7.4)
-    return nCmp(left, right);
-}
-
 // to send numbers instead of strings with suffixes
 QString Utils::String::fromDouble(double n, int precision)
 {
diff --git a/src/base/utils/string.h b/src/base/utils/string.h
index 9a3c66843..8ca2f2e45 100644
--- a/src/base/utils/string.h
+++ b/src/base/utils/string.h
@@ -47,7 +47,8 @@ namespace Utils
         // Taken from https://crackstation.net/hashing-security.htm
         bool slowEquals(const QByteArray &a, const QByteArray &b);
 
-        bool naturalCompare(const QString &left, const QString &right);
+        bool naturalCompareCaseSensitive(const QString &left, const QString &right);
+        bool naturalCompareCaseInsensitive(const QString &left, const QString &right);
     }
 }
 
diff --git a/src/gui/addnewtorrentdialog.cpp b/src/gui/addnewtorrentdialog.cpp
index 3511ef73f..a689c0b86 100644
--- a/src/gui/addnewtorrentdialog.cpp
+++ b/src/gui/addnewtorrentdialog.cpp
@@ -96,7 +96,7 @@ AddNewTorrentDialog::AddNewTorrentDialog(QWidget *parent)
 
     // Load categories
     QStringList categories = session->categories();
-    std::sort(categories.begin(), categories.end(), Utils::String::naturalCompare);
+    std::sort(categories.begin(), categories.end(), Utils::String::naturalCompareCaseInsensitive);
     QString defaultCategory = settings()->loadValue(KEY_DEFAULTCATEGORY).toString();
 
     if (!defaultCategory.isEmpty())
diff --git a/src/gui/properties/peerlistsortmodel.h b/src/gui/properties/peerlistsortmodel.h
index ac298a3da..729d92bfa 100644
--- a/src/gui/properties/peerlistsortmodel.h
+++ b/src/gui/properties/peerlistsortmodel.h
@@ -48,7 +48,7 @@ protected:
   case PeerListDelegate::CLIENT: {
     QString vL = left.data().toString();
     QString vR = right.data().toString();
-    return Utils::String::naturalCompare(vL, vR);
+    return Utils::String::naturalCompareCaseSensitive(vL, vR);
   }
   };
 
diff --git a/src/gui/rss/automatedrssdownloader.cpp b/src/gui/rss/automatedrssdownloader.cpp
index 744229710..4396d106e 100644
--- a/src/gui/rss/automatedrssdownloader.cpp
+++ b/src/gui/rss/automatedrssdownloader.cpp
@@ -314,7 +314,7 @@ void AutomatedRssDownloader::initCategoryCombobox()
 {
   // Load torrent categories
   QStringList categories = BitTorrent::Session::instance()->categories();
-  std::sort(categories.begin(), categories.end(), Utils::String::naturalCompare);
+  std::sort(categories.begin(), categories.end(), Utils::String::naturalCompareCaseInsensitive);
   ui->comboCategory->addItems(categories);
 }
 
diff --git a/src/gui/search/searchsortmodel.cpp b/src/gui/search/searchsortmodel.cpp
index 0052029eb..e27af9fc8 100644
--- a/src/gui/search/searchsortmodel.cpp
+++ b/src/gui/search/searchsortmodel.cpp
@@ -112,7 +112,7 @@ bool SearchSortModel::lessThan(const QModelIndex &left, const QModelIndex &right
     case ENGINE_URL: {
         QString vL = left.data().toString();
         QString vR = right.data().toString();
-        return Utils::String::naturalCompare(vL, vR);
+        return Utils::String::naturalCompareCaseSensitive(vL, vR);
     }
 
     default:
diff --git a/src/gui/torrentcontentfiltermodel.cpp b/src/gui/torrentcontentfiltermodel.cpp
index fb4d849b1..bb957c92d 100644
--- a/src/gui/torrentcontentfiltermodel.cpp
+++ b/src/gui/torrentcontentfiltermodel.cpp
@@ -90,7 +90,7 @@ bool TorrentContentFilterModel::lessThan(const QModelIndex &left, const QModelIn
     TorrentContentModelItem::ItemType rightType = m_model->itemType(m_model->index(right.row(), 0, right.parent()));
 
     if (leftType == rightType)
-      return Utils::String::naturalCompare(vL, vR);
+      return Utils::String::naturalCompareCaseSensitive(vL, vR);
     else if (leftType == TorrentContentModelItem::FolderType && sortOrder() == Qt::AscendingOrder)
       return true;
     else
diff --git a/src/gui/transferlistfilterswidget.cpp b/src/gui/transferlistfilterswidget.cpp
index a2da34141..eaa8e9d01 100644
--- a/src/gui/transferlistfilterswidget.cpp
+++ b/src/gui/transferlistfilterswidget.cpp
@@ -239,7 +239,7 @@ void CategoryFiltersList::addItem(const QString &category, bool hasTorrent)
     Q_ASSERT(count() >= 2);
     int insPos = count();
     for (int i = 2; i < count(); ++i) {
-        if (Utils::String::naturalCompare(category, item(i)->text())) {
+        if (Utils::String::naturalCompareCaseSensitive(category, item(i)->text())) {
             insPos = i;
             break;
         }
@@ -511,7 +511,7 @@ void TrackerFiltersList::addItem(const QString &tracker, const QString &hash)
     Q_ASSERT(count() >= 4);
     int insPos = count();
     for (int i = 4; i < count(); ++i) {
-        if (Utils::String::naturalCompare(host, item(i)->text())) {
+        if (Utils::String::naturalCompareCaseSensitive(host, item(i)->text())) {
             insPos = i;
             break;
         }
diff --git a/src/gui/transferlistsortmodel.cpp b/src/gui/transferlistsortmodel.cpp
index 06eeed220..2058ce91f 100644
--- a/src/gui/transferlistsortmodel.cpp
+++ b/src/gui/transferlistsortmodel.cpp
@@ -80,7 +80,7 @@ bool TransferListSortModel::lessThan(const QModelIndex &left, const QModelIndex
         if (!vL.isValid() || !vR.isValid() || (vL == vR))
             return lowerPositionThan(left, right);
 
-        return Utils::String::naturalCompare(vL.toString(), vR.toString());
+        return Utils::String::naturalCompareCaseSensitive(vL.toString(), vR.toString());
     }
 
     case TorrentModel::TR_ADD_DATE:
diff --git a/src/gui/transferlistwidget.cpp b/src/gui/transferlistwidget.cpp
index d147f8c6c..c7e25409e 100644
--- a/src/gui/transferlistwidget.cpp
+++ b/src/gui/transferlistwidget.cpp
@@ -769,7 +769,7 @@ void TransferListWidget::displayListMenu(const QPoint&)
         listMenu.addAction(&actionRename);
     // Category Menu
     QStringList categories = BitTorrent::Session::instance()->categories();
-    std::sort(categories.begin(), categories.end(), Utils::String::naturalCompare);
+    std::sort(categories.begin(), categories.end(), Utils::String::naturalCompareCaseInsensitive);
     QList<QAction*> categoryActions;
     QMenu *categoryMenu = listMenu.addMenu(GuiIconProvider::instance()->getIcon("view-categories"), tr("Category"));
     categoryActions << categoryMenu->addAction(GuiIconProvider::instance()->getIcon("list-add"), tr("New...", "New category..."));