Allow drop action only on transfer list

Now drop action is only allowed on transfer list, previously it was on main window.
Having drop action on the whole main window is not preferred because it could allow drop action
on other unrelated widgets, such as execution log or RSS widget which is unexpected behavior.

PR #21332.

src/base/utils/misc.cpp

@@ -47,6 +47,7 @@
 #include <QStringView>
 #include <QSysInfo>
 
+#include "base/net/downloadmanager.h"
 #include "base/path.h"
 #include "base/unicodestrings.h"
 #include "base/utils/string.h"
@@ -212,6 +213,14 @@ bool Utils::Misc::isPreviewable(const Path &filePath)
     return multimediaExtensions.contains(filePath.extension().toUpper());
 }
 
+bool Utils::Misc::isTorrentLink(const QString &str)
+{
+    return str.startsWith(u"magnet:", Qt::CaseInsensitive)
+        || str.endsWith(TORRENT_FILE_EXTENSION, Qt::CaseInsensitive)
+        || (!str.startsWith(u"file:", Qt::CaseInsensitive)
+            && Net::DownloadManager::hasSupportedScheme(str));
+}
+
 QString Utils::Misc::userFriendlyDuration(const qlonglong seconds, const qlonglong maxCap, const TimeResolution resolution)
 {
     if (seconds < 0)

src/base/utils/misc.h

@@ -78,6 +78,7 @@ namespace Utils::Misc
     qint64 sizeInBytes(qreal size, SizeUnit unit);
 
     bool isPreviewable(const Path &filePath);
+    bool isTorrentLink(const QString &str);
 
     // Take a number of seconds and return a user-friendly
     // time duration like "1d 2h 10m".