Inno Setup get directory size including subdirectories - inno-setup

Question

I am trying to write a function that returns the size of a directory. I have written the following code, but it is not returning the correct size. For example, when I run it on the {pf} directory it returns 174 bytes, which is clearly wrong as this directory is multiple Gigabytes in size. Here is the code I have:
function GetDirSize(DirName: String): Int64;
var
FindRec: TFindRec;
begin
if FindFirst(DirName + '\*', FindRec) then
begin
try
repeat
Result := Result + (Int64(FindRec.SizeHigh) shl 32 + FindRec.SizeLow);
until not FindNext(FindRec);
finally
FindClose(FindRec);
end;
end
else
begin
Result := -1;
end;
end;
I suspect that the FindFirst function does not include subdirectories, which is why I am not getting the correct result. Therefore, how can I return the correct size of a directory i.e. including all files in all subdirectories, the same as selecting Properties on a Folder in Windows Explorer? I am using FindFirst as the function needs to support directory sizes over 2GB.

Answer 1

The FindFirst does include subdirectories, but it won't get you their sizes.
You have to recurse into subdirectories and calculate the total size file by file, similarly as to for example Inno Setup: copy folder, subfolders and files recursively in Code section.
function GetDirSize(Path: String): Int64;
var
FindRec: TFindRec;
FilePath: string;
Size: Int64;
begin
if FindFirst(Path + '\*', FindRec) then
begin
Result := 0;
try
repeat
if (FindRec.Name <> '.') and (FindRec.Name <> '..') then
begin
FilePath := Path + '\' + FindRec.Name;
if (FindRec.Attributes and FILE_ATTRIBUTE_DIRECTORY) <> 0 then
begin
Size := GetDirSize(FilePath);
end
else
begin
Size := Int64(FindRec.SizeHigh) shl 32 + FindRec.SizeLow;
end;
Result := Result + Size;
end;
until not FindNext(FindRec);
finally
FindClose(FindRec);
end;
end
else
begin
Log(Format('Failed to list %s', [Path]));
Result := -1;
end;
end;
For Int64, you need Unicode version of Inno Setup, what you should be using in any case. Only if you have a very good reason to stick with Ansi version, you can replace the Int64 with Integer, but than you are limited to 2 GB.