Windows: Sync .lnk files correctly. #2792

src/libsync/filesystem.cpp

@@ -49,7 +49,7 @@ bool FileSystem::fileEquals(const QString& fn1, const QString& fn2)
         return false;
     }
 
-    if (f1.size() != f2.size()) {
+    if (getSize(fn1) != getSize(fn2)) {
         return false;
     }
 
@@ -82,12 +82,9 @@ time_t FileSystem::getModTime(const QString &filename)
     csync_vio_file_stat_t* stat = csync_vio_file_stat_new();
     qint64 result = -1;
     if (csync_vio_local_stat(filename.toUtf8().data(), stat) != -1
-            && (stat->fields & CSYNC_VIO_FILE_STAT_FIELDS_MTIME))
-    {
+            && (stat->fields & CSYNC_VIO_FILE_STAT_FIELDS_MTIME)) {
         result = stat->mtime;
-    }
-    else
-    {
+    } else {
         qDebug() << "Could not get modification time for" << filename
                  << "with csync, using QFileInfo";
         result = Utility::qDateTimeToTime_t(QFileInfo(filename).lastModified());
@@ -217,6 +214,26 @@ bool FileSystem::openFileSharedRead(QFile* file, QString* error)
     return ok;
 }
 
+qint64 FileSystem::getSize(const QString& filename)
+{
+#ifdef Q_OS_WIN
+    if (filename.endsWith(".lnk")) {
+        // Use csync to get the file size. Qt seems unable to get at it.
+        qint64 result = 0;
+        csync_vio_file_stat_t* stat = csync_vio_file_stat_new();
+        if (csync_vio_local_stat(filename.toUtf8().data(), stat) != -1
+                && (stat->fields & CSYNC_VIO_FILE_STAT_FIELDS_SIZE)) {
+            result = stat->size;
+        } else {
+            qDebug() << "Could not get size time for" << filename << "with csync";
+        }
+        csync_vio_file_stat_destroy(stat);
+        return result;
+    }
+#endif
+    return QFileInfo(filename).size();
+}
+
 #ifdef Q_OS_WIN
 QString FileSystem::fileSystemForPath(const QString & path)
 {

src/libsync/filesystem.h

@@ -43,6 +43,13 @@ time_t OWNCLOUDSYNC_EXPORT getModTime(const QString &filename);
 
 bool setModTime(const QString &filename, time_t modTime);
 
+/** Get the size for a file.
+ *
+ * Use this over QFileInfo::size() to avoid bugs with lnk files on Windows.
+ * See https://bugreports.qt.io/browse/QTBUG-24831.
+ */
+qint64 OWNCLOUDSYNC_EXPORT getSize(const QString& filename);
+
 /**
  * Rename the file \a originFileName to \a destinationFileName, and overwrite the destination if it
  * already exists

src/libsync/propagatedownload.cpp

@@ -517,11 +517,10 @@ void PropagateDownloadFileQNAM::downloadFinished()
         return;
     }
 
-    existingFile.refresh();
     // Maybe we downloaded a newer version of the file than we thought we would...
     // Get up to date information for the journal.
     FileSystem::setModTime(fn, _item._modtime);
-    _item._size = existingFile.size();
+    _item._size = FileSystem::getSize(fn);
 
     _propagator->_journal->setFileRecord(SyncJournalFileRecord(_item, fn));
     _propagator->_journal->setDownloadInfo(_item._file, SyncJournalDb::DownloadInfo());

src/libsync/propagateupload.cpp

@@ -159,7 +159,7 @@ void PropagateUploadFileQNAM::start()
 
     // Update the mtime and size, it might have changed since discovery.
     _item._modtime = FileSystem::getModTime(fi.absoluteFilePath());
-    quint64 fileSize = fi.size();
+    quint64 fileSize = FileSystem::getSize(fi.absoluteFilePath());
     _item._size = fileSize;
 
     // But skip the file if the mtime is too close to 'now'!
@@ -220,7 +220,7 @@ bool UploadDevice::prepareAndOpen(const QString& fileName, qint64 start, qint64
         return false;
     }
 
-    size = qMin(file.size(), size);
+    size = qMin(FileSystem::getSize(fileName), size);
     _data.resize(size);
     if (!file.seek(start)) {
         setErrorString(file.errorString());
@@ -501,7 +501,7 @@ void PropagateUploadFileQNAM::slotPutFinished()
 
     // compare expected and real modification time of the file and size
     const time_t new_mtime = FileSystem::getModTime(fi.absoluteFilePath());
-    const quint64 new_size = static_cast<quint64>(fi.size());
+    const quint64 new_size = static_cast<quint64>(FileSystem::getSize(fi.absoluteFilePath()));
     if (new_mtime != _item._modtime || new_size != _item._size) {
         qDebug() << "The local file has changed during upload:"
                  << "mtime: " << _item._modtime << "<->" << new_mtime

src/libsync/propagatorjobs.cpp

@@ -48,6 +48,8 @@ static bool removeRecursively(const QString &path, QString &error)
         di.next();
         const QFileInfo& fi = di.fileInfo();
         bool ok;
+        // The use of isSymLink here is okay:
+        // we never want to go into this branch for .lnk files
         if (fi.isDir() && !fi.isSymLink()) {
             ok = removeRecursively(di.filePath(), error); // recursive
         } else {