Properly remove empty leftover folders after rename

TorrentInfo::origFilePath will return the very original path from
.torrent file, not the most recent file path before the rename operation
and thus the code would not be working as we expected.

src/base/bittorrent/torrenthandle.cpp

@@ -59,6 +59,7 @@
 #include "base/profile.h"
 #include "base/tristatebool.h"
 #include "base/utils/fs.h"
+#include "base/utils/string.h"
 #include "downloadpriority.h"
 #include "peerinfo.h"
 #include "session.h"
@@ -1481,6 +1482,7 @@ void TorrentHandle::moveStorage(const QString &newPath, bool overwrite)
 
 void TorrentHandle::renameFile(const int index, const QString &name)
 {
+    m_oldPath[LTFileIndex {index}].push_back(filePath(index));
     ++m_renameCount;
     m_nativeHandle.rename_file(index, Utils::Fs::toNativePath(name).toStdString());
 }
@@ -1744,29 +1746,42 @@ void TorrentHandle::handleFastResumeRejectedAlert(const lt::fastresume_rejected_
 
 void TorrentHandle::handleFileRenamedAlert(const lt::file_renamed_alert *p)
 {
-    const QString newName = Utils::Fs::fromNativePath(p->new_name());
-
-    // TODO: Check this!
-    if (filesCount() > 1) {
-        // Check if folders were renamed
-        QStringList oldPathParts = m_torrentInfo.origFilePath(p->index).split('/');
-        oldPathParts.removeLast();
-        QString oldPath = oldPathParts.join('/');
-        QStringList newPathParts = newName.split('/');
-        newPathParts.removeLast();
-        const QString newPath = newPathParts.join('/');
-        if (!newPathParts.isEmpty() && (oldPath != newPath)) {
-            qDebug("oldPath(%s) != newPath(%s)", qUtf8Printable(oldPath), qUtf8Printable(newPath));
-            oldPath = QString("%1/%2").arg(savePath(true), oldPath);
-            qDebug("Detected folder renaming, attempt to delete old folder: %s", qUtf8Printable(oldPath));
-            QDir().rmpath(oldPath);
-        }
-    }
-
     // We don't really need to call updateStatus() in this place.
     // All we need to do is make sure we have a valid instance of the TorrentInfo object.
     m_torrentInfo = TorrentInfo {m_nativeHandle.torrent_file()};
 
+    // remove empty leftover folders
+    // for example renaming "a/b/c" to "d/b/c", then folders "a/b" and "a" will
+    // be removed if they are empty
+    const QString oldFilePath = m_oldPath[LTFileIndex {p->index}].takeFirst();
+    const QString newFilePath = Utils::Fs::fromNativePath(p->new_name());
+
+    if (m_oldPath[LTFileIndex {p->index}].isEmpty())
+        m_oldPath.remove(LTFileIndex {p->index});
+
+    QVector<QStringRef> oldPathParts = oldFilePath.splitRef('/', QString::SkipEmptyParts);
+    oldPathParts.removeLast();  // drop file name part
+    QVector<QStringRef> newPathParts = newFilePath.splitRef('/', QString::SkipEmptyParts);
+    newPathParts.removeLast();  // drop file name part
+
+#if defined(Q_OS_WIN)
+    const Qt::CaseSensitivity caseSensitivity = Qt::CaseInsensitive;
+#else
+    const Qt::CaseSensitivity caseSensitivity = Qt::CaseSensitive;
+#endif
+
+    int pathIdx = 0;
+    while ((pathIdx < oldPathParts.size()) && (pathIdx < newPathParts.size())) {
+        if (oldPathParts[pathIdx].compare(newPathParts[pathIdx], caseSensitivity) != 0)
+            break;
+        ++pathIdx;
+    }
+
+    for (int i = (oldPathParts.size() - 1); i >= pathIdx; --i) {
+        QDir().rmdir(savePath() + Utils::String::join(oldPathParts, QLatin1String("/")));
+        oldPathParts.removeLast();
+    }
+
     --m_renameCount;
     while (!isMoveInProgress() && (m_renameCount == 0) && !m_moveFinishedTriggers.isEmpty())
         m_moveFinishedTriggers.takeFirst()();
@@ -1774,12 +1789,14 @@ void TorrentHandle::handleFileRenamedAlert(const lt::file_renamed_alert *p)
 
 void TorrentHandle::handleFileRenameFailedAlert(const lt::file_rename_failed_alert *p)
 {
-    Q_UNUSED(p);
-
     LogMsg(tr("File rename failed. Torrent: \"%1\", file: \"%2\", reason: \"%3\"")
         .arg(name(), filePath(p->index)
              , QString::fromStdString(p->error.message())), Log::WARNING);
 
+    m_oldPath[LTFileIndex {p->index}].removeFirst();
+    if (m_oldPath[LTFileIndex {p->index}].isEmpty())
+        m_oldPath.remove(LTFileIndex {p->index});
+
     --m_renameCount;
     while (!isMoveInProgress() && (m_renameCount == 0) && !m_moveFinishedTriggers.isEmpty())
         m_moveFinishedTriggers.takeFirst()();

src/base/bittorrent/torrenthandle.h

@@ -355,6 +355,12 @@ namespace BitTorrent
     private:
         typedef std::function<void ()> EventTrigger;
 
+#if (LIBTORRENT_VERSION_NUM < 10200)
+        using LTFileIndex = int;
+#else
+        using LTFileIndex = lt::file_index_t;
+#endif
+
         void updateStatus();
         void updateStatus(const lt::torrent_status &nativeStatus);
         void updateState();
@@ -417,6 +423,10 @@ namespace BitTorrent
         QQueue<EventTrigger> m_moveFinishedTriggers;
         int m_renameCount;
 
+        // Until libtorrent provide an "old_name" field in `file_renamed_alert`
+        // we will rely on this workaround to remove empty leftover folders
+        QHash<LTFileIndex, QVector<QString>> m_oldPath;
+
         bool m_useAutoTMM;
 
         // Persistent data

src/base/utils/string.cpp

@@ -198,3 +198,14 @@ TriStateBool Utils::String::parseTriStateBool(const QString &string)
         return TriStateBool::False;
     return TriStateBool::Undefined;
 }
+
+QString Utils::String::join(const QVector<QStringRef> &strings, const QString &separator)
+{
+    if (strings.empty())
+        return {};
+
+    QString ret = strings[0].toString();
+    for (int i = 1; i < strings.count(); ++i)
+        ret += (separator + strings[i]);
+    return ret;
+}

src/base/utils/string.h

@@ -31,8 +31,10 @@
 #define UTILS_STRING_H
 
 #include <QLatin1String>
+#include <QVector>
 
 class QString;
+class QStringRef;
 
 class TriStateBool;
 
@@ -66,6 +68,8 @@ namespace Utils
 
         bool parseBool(const QString &string, bool defaultValue);
         TriStateBool parseTriStateBool(const QString &string);
+
+        QString join(const QVector<QStringRef> &strings, const QString &separator);
     }
 }
 

src/gui/torrentcontenttreeview.cpp

@@ -204,15 +204,6 @@ void TorrentContentTreeView::renameSelectedFile(BitTorrent::TorrentHandle *torre
         if (needForceRecheck)
             torrent->forceRecheck();
 
-        // Remove old folder
-        const QString oldFullPath = torrent->savePath(true) + oldPath;
-        int timeout = 10;
-        while (!QDir().rmpath(oldFullPath) && (timeout > 0)) {
-            // FIXME: We should not sleep here (freezes the UI for 1 second)
-            QThread::msleep(100);
-            --timeout;
-        }
-
         model->setData(modelIndex, newName);
     }
 }