Mega Code Archive
Imitating DelTree
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Title: Imitating DelTree
Question: How can I delete a directory (with all its subdirectories)?
Answer:
DelTree
-------
The command-line program DELTREE.EXE that comes with Windows removes
a directory with all its files and subdirectories. To mimic this
behaviour in Delphi we can use the following procedure that uses the
FindFirst, FindNext and FindClose functions to perform the file and
directory search:
uses FileCtrl;
procedure DelTree(const Directory: TFileName);
var
DrivesPathsBuff: array[0..1024] of char;
DrivesPaths: string;
len: longword;
ShortPath: array[0..MAX_PATH] of char;
dir: TFileName;
procedure rDelTree(const Directory: TFileName);
// Recursively deletes all files and directories
// inside the directory passed as parameter.
var
SearchRec: TSearchRec;
Attributes: LongWord;
ShortName, FullName: TFileName;
pname: pchar;
begin
if FindFirst(Directory + '*', faAnyFile and not faVolumeID,
SearchRec) = 0 then begin
try
repeat // Processes all files and directories
if SearchRec.FindData.cAlternateFileName[0] = #0 then
ShortName := SearchRec.Name
else
ShortName := SearchRec.FindData.cAlternateFileName;
FullName := Directory + ShortName;
if (SearchRec.Attr and faDirectory) 0 then begin
// It's a directory
if (ShortName '.') and (ShortName '..') then
rDelTree(FullName + '\');
end else begin
// It's a file
pname := PChar(FullName);
Attributes := GetFileAttributes(pname);
if Attributes = $FFFFFFFF then
raise EInOutError.Create(SysErrorMessage(GetLastError));
if (Attributes and FILE_ATTRIBUTE_READONLY) 0 then
SetFileAttributes(pname, Attributes and not
FILE_ATTRIBUTE_READONLY);
if Windows.DeleteFile(pname) = False then
raise EInOutError.Create(SysErrorMessage(GetLastError));
end;
until FindNext(SearchRec) 0;
except
FindClose(SearchRec);
raise;
end;
FindClose(SearchRec);
end;
if Pos(#0 + Directory + #0, DrivesPaths) = 0 then begin
// if not a root directory, remove it
pname := PChar(Directory);
Attributes := GetFileAttributes(pname);
if Attributes = $FFFFFFFF then
raise EInOutError.Create(SysErrorMessage(GetLastError));
if (Attributes and FILE_ATTRIBUTE_READONLY) 0 then
SetFileAttributes(pname, Attributes and not
FILE_ATTRIBUTE_READONLY);
if Windows.RemoveDirectory(pname) = False then begin
raise EInOutError.Create(SysErrorMessage(GetLastError));
end;
end;
end;
// ----------------
begin
DrivesPathsBuff[0] := #0;
len := GetLogicalDriveStrings(1022, @DrivesPathsBuff[1]);
if len = 0 then
raise EInOutError.Create(SysErrorMessage(GetLastError));
SetString(DrivesPaths, DrivesPathsBuff, len + 1);
DrivesPaths := Uppercase(DrivesPaths);
len := GetShortPathName(PChar(Directory), ShortPath, MAX_PATH);
if len = 0 then
raise EInOutError.Create(SysErrorMessage(GetLastError));
SetString(dir, ShortPath, len);
dir := Uppercase(dir);
rDelTree(IncludeTrailingBackslash(dir));
end;
Sample calls
------------
This code will remove the directory C:\TEMP\A123:
DelTree('C:\TEMP\A123');
And this code will wipe out the diskette in drive A:
DelTree('A:'); // or DelTree('A:\');
WARNING
-------
The procedure DelTree presented here erases files and directories, and
they might not be recoverable later. It is provided in the belief that
it is useful, but you use it at our own risk.
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