Detecting If a Directory Is a Junction in Delphi
I've Been Google Searching This I May Be Having Some Brain Clouds Because It Just Isn't Working. I Need to Detect If a Folder Is a Junction So My Recursive...
I've been Google searching this I may be having some brain clouds because it just isn't working.
I need to detect if a folder is a junction so my recursive file search doesn't run off into an endless loop.
I could use a simple function like
IsJunction(attr: dword): boolean;
where attr is dwFileAttributes from TWin32FindData;
I just can't seem to get it to work. Thanks!
2 Answers
dwFileAttributes of TWin32FindData does not have that information, you have to look to the dwReserved0 field. See documentation.
function IsJunction(const FileName: string): Boolean;
// IO_REPARSE_TAG_MOUNT_POINT = $A0000003;
var
FindHandle: THandle;
FindData: TWin32FindData;
begin
Result := False;
FindHandle := FindFirstFile(PChar(FileName), FindData);
if FindHandle <> INVALID_HANDLE_VALUE then begin
Result := (Bool(FindData.dwFileAttributes and FILE_ATTRIBUTE_REPARSE_POINT))
and Bool(FindData.dwReserved0 and $80000000) // MS bit
and Bool(FindData.dwReserved0 and $20000000) // name surrogate bit
and (LoWord(FindData.dwReserved0) = 3); // mount point value
winapi.windows.FindClose(FindHandle);
end else
RaiseLastOSError;
end;
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