Today's Code snippet comes to us from Jeff Miller. He was asked to take a look at a script that was running slowly. This script opened a file and read it in. One of the very first things he noticed was something that was happening with each pass of the loop that read the file.

He writes, "I noticed first off that the file was being re-opened with each pass of the loop and somehow it was managing to process each line of the file by only using ReadLine."

It's no surprise that Jeff called this setup "The Fragmenter"

Sitting innocently near the end of the function was a jewel, waiting to be discovered. The Jewel of the File: Delete_Line.

Private Sub ProcessFile(strFileName)
    …
    Do Until blnLastTime = True
        
        Set fileReader = fso.OpenTextFile(strFileName)
        
         If fileReader.AtEndOfStream = True Then
            blnLastTime = True
         Else
            strTextLine = fileReader.ReadLine
         End If

        ….
         
        fileReader.Close
        Delete_Line (strFileName)
    Loop
    fileReader.Close

End Sub



Private Sub Delete_Line(strFile)

    Set fileReader = fso.OpenTextFile(strFile)
    
    If fso.FileExists(strFile & "2") Then
        fso.DeleteFile (strFile & "2")
    End If
    
    Set fileWriter = fso.CreateTextFile(strFile & 2)
    
    If fileReader.AtEndOfStream = False Then
        fileReader.ReadLine
    End If
    
    If fileReader.AtEndOfStream = False Then
            strLine = fileReader.ReadAll
            fileWriter.Write (strLine)
    End If
    
    
    fileReader.Close
    fileWriter.Close

    fso.DeleteFile strFile, True
    fso.CopyFile strFile & "2", strFile, True
    fso.DeleteFile strFile & 2, True
    
End Sub

Moral of the story? Opening files is never trivial, especially in a loop, but multiple times - heart attack! Also,before calling a function inside a loop, find out what that function does. And... Oh never mind, there are too many to list.

What's your moral of the story?

[Advertisement] BuildMaster allows you to create a self-service release management platform that allows different teams to manage their applications. Explore how!