1 files changed, 67 insertions, 0 deletions
diff --git a/zen/file_id.cpp b/zen/file_id.cpp
new file mode 100644
index 00000000..c9f422ac
--- /dev/null
+++ b/zen/file_id.cpp
@@ -0,0 +1,67 @@
+// **************************************************************************
+// * This file is part of the FreeFileSync project. It is distributed under *
+// * GNU General Public License: http://www.gnu.org/licenses/gpl.html       *
+// * Copyright (C) 2008-2011 ZenJu (zhnmju123 AT gmx.de)                    *
+// **************************************************************************
+
+#include "file_id.h"
+#include "file_id_internal.h"
+
+#ifdef FFS_WIN
+#include "win.h" //includes "windows.h"
+#include "long_path_prefix.h"
+#include "scope_guard.h"
+
+#elif defined FFS_LINUX
+#include <sys/stat.h>
+#endif
+
+
+std::string zen::getFileID(const Zstring& filename)
+{
+#ifdef FFS_WIN
+    //WARNING: CreateFile() is SLOW, while GetFileInformationByHandle() is cheap!
+    //http://msdn.microsoft.com/en-us/library/aa363788(VS.85).aspx
+
+    //privilege SE_BACKUP_NAME doesn't seem to be required here at all
+
+    const HANDLE hFile = ::CreateFile(zen::applyLongPathPrefix(filename).c_str(),
+                                      0,
+                                      FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE,
+                                      0,
+                                      OPEN_EXISTING,
+                                      FILE_FLAG_OPEN_REPARSE_POINT | FILE_FLAG_BACKUP_SEMANTICS, //FILE_FLAG_BACKUP_SEMANTICS needed to open a directory
+                                      NULL);
+    if (hFile != INVALID_HANDLE_VALUE)
+    {
+        ZEN_ON_BLOCK_EXIT(::CloseHandle(hFile));
+
+        BY_HANDLE_FILE_INFORMATION fileInfo = {};
+        if (::GetFileInformationByHandle(hFile, &fileInfo))
+            return extractFileID(fileInfo);
+    }
+
+#elif defined FFS_LINUX
+    struct ::stat fileInfo = {};
+    if (::lstat(filename.c_str(), &fileInfo) == 0) //lstat() does not follow symlinks
+        return extractFileID(fileInfo);
+#endif
+
+    assert(false);
+    return std::string();
+}
+
+
+bool zen::samePhysicalFile(const Zstring& file1, const Zstring& file2)
+{
+    if (EqualFilename()(file1, file2)) //quick check
+        return true;
+
+    const std::string id1 = getFileID(file1);
+    const std::string id2 = getFileID(file2);
+
+    if (id1.empty() || id2.empty())
+        return false;
+
+    return id1 == id2;
+}