Tk Library Source Code

The git-archive utility has an option --prefix described as:

  --prefix=<prefix>/
      Prepend <prefix>/ to each filename in the archive.

I found this useful in the case that the the parent directory of what I'm wrapping up as a tarball isn't named the way I'd like root directory within the tarball to be named. However, I also needed to add a few files to the tarball, and my command-line tar didn't have a corresponding option. Therefore I turned to adding a -prefix option to the tcllib [tar::add] command.

The main change needed to implement this was to split [tar::createHeader] into two commands [tar::statFile] and [tar::formatHeader], as [tar::createHeader] hardwired the in-archive name of a file to be the same as the name in the normal file system. I think this is a good change, as it also opens up for adding items to a tarball that don't first have to exist within the normal filesystem (a kind of [tar::put], if you will).

Another change required was that [tar::writefile] takes another argument: the name to use in the archive. [tar::add] and [tar::create] have been modified accordingly.

While testing this, I also discovered a bug in the current [tar::add]: one cannot in general assume that the end of an archive occurs 1024 bytes before the end of the file. The catch is that tarballs are written with a specific "blocksize" (often 20 records, i.e., 10Kb), and are supposed to consist of an integral number of complete blocks. Therefore there may be extra padding after the 1024 end-of-archive nulls, and it is then impossible to tell if an all-null record at the end of a tarball is nulls at the end of a file, end-of-archive nulls, or padding until the end of a block. The only safe way to find the end is to read the tarball from the beginning.

I added a third option -quick to [tar::add] which selects the old seek-from-end method of finding where to put the header for the first new file, but made the default be to read the tarball from start.

Being a tcllib developer, I can probably check this into CVS myself, but I think you should have a chance to look at it first.

This type of putting up an RC and freezing CVS before actually doing the release is mainly there to flush out all the people who have such last-minute stuff and sort of forgot that we are working on making a release. A last wakeup call. I definitely expected for stuff like this come out of the woodwork with my declaration.

The declaration also said 'If changes are needed before 1.12 is released coordinate with me.'.

Which Aaron did, pinging me on the chat. I reviewed and decided to apply, i.e. decided hat I want to have this in 1.12. It was not Aaron going over my declaration.

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This got added /after/ today's declaration of a CVS being frozen? Still, it's good that it got in; I've been thinking about this the last couple of weeks, but also been too busy to get around to it.

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Committed to head. Updated the tar.pcx.

File Added - 339706: tar.patch