Index: src/ch/TLocalFilesystem.h
===================================================================
diff -u -N -r886c32a98f09ae8dc24ceb6b27e5c8a75104954e -r4c09a2d7ab35a30114ff2b7c4db12bc413bf538c
--- src/ch/TLocalFilesystem.h	(.../TLocalFilesystem.h)	(revision 886c32a98f09ae8dc24ceb6b27e5c8a75104954e)
+++ src/ch/TLocalFilesystem.h	(.../TLocalFilesystem.h)	(revision 4c09a2d7ab35a30114ff2b7c4db12bc413bf538c)
@@ -24,6 +24,8 @@
 #define __TLOCALFILESYSTEM_H__
 
 #include "../libchcore/TPath.h"
+#include <boost/smart_ptr/shared_array.hpp>
+#include <boost/thread/shared_mutex.hpp>
 
 class CFileInfo;
 typedef boost::shared_ptr<CFileInfo> CFileInfoPtr;
@@ -36,6 +38,16 @@
 class TLocalFilesystem
 {
 public:
+	enum EPathsRelation
+	{
+		eRelation_Network,				// at least one of the paths is network one
+		eRelation_CDRom,				// at least one of the paths relates to cd/dvd drive
+		eRelation_TwoPhysicalDisks,		// paths lies on two separate physical disks
+		eRelation_SinglePhysicalDisk,	// paths lies on the same physical disk
+		eRelation_Other					// other type of relation
+	};
+
+public:
 	static void GetDriveData(const chcore::TSmartPath& spPath, int *piDrvNum, UINT *puiDrvType);
 	static bool PathExist(chcore::TSmartPath strPath);	// check for file or folder existence
 
@@ -52,9 +64,16 @@
 	static TLocalFilesystemFind CreateFinderObject(const chcore::TSmartPath& pathDir, const chcore::TSmartPath& pathMask);
 	static TLocalFilesystemFile CreateFileObject();
 
+	EPathsRelation GetPathsRelation(const chcore::TSmartPath& pathFirst, const chcore::TSmartPath& pathSecond);
+
 private:
 	static chcore::TSmartPath PrependPathExtensionIfNeeded(const chcore::TSmartPath& pathInput);
+	DWORD  GetPhysicalDiskNumber(wchar_t wchDrive);
 
+private:
+	std::map<wchar_t, DWORD> m_mapDriveLetterToPhysicalDisk;	// caches drive letter -> physical disk number
+	boost::shared_mutex m_lockDriveLetterToPhysicalDisk;
+
 	friend class TLocalFilesystemFind;
 	friend class TLocalFilesystemFile;
 };