From mboxrd@z Thu Jan 1 00:00:00 1970 From: Carl Baldwin Subject: Re: [RFC] undo and redo Date: Wed, 24 Aug 2005 12:10:04 -0600 Organization: Hewlett Packard Message-ID: <20050824181004.GA18790@hpsvcnb.fc.hp.com> References: <20050824172339.GA7083@hpsvcnb.fc.hp.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: git@vger.kernel.org X-From: git-owner@vger.kernel.org Wed Aug 24 20:12:35 2005 Return-path: Received: from vger.kernel.org ([209.132.176.167]) by ciao.gmane.org with esmtp (Exim 4.43) id 1E7zhc-0001AL-8n for gcvg-git@gmane.org; Wed, 24 Aug 2005 20:10:20 +0200 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751340AbVHXSKG (ORCPT ); Wed, 24 Aug 2005 14:10:06 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751342AbVHXSKG (ORCPT ); Wed, 24 Aug 2005 14:10:06 -0400 Received: from atlrel8.hp.com ([156.153.255.206]:63174 "EHLO atlrel8.hp.com") by vger.kernel.org with ESMTP id S1751340AbVHXSKF (ORCPT ); Wed, 24 Aug 2005 14:10:05 -0400 Received: from smtp1.fc.hp.com (smtp1b.fc.hp.com [15.15.136.127]) by atlrel8.hp.com (Postfix) with ESMTP id D01131DD6 for ; Wed, 24 Aug 2005 14:10:04 -0400 (EDT) Received: from hpsvcnb.fc.hp.com (hpsvcnb.fc.hp.com [15.6.94.42]) by smtp1.fc.hp.com (Postfix) with ESMTP id 9CDC538412 for ; Wed, 24 Aug 2005 18:10:04 +0000 (UTC) Received: by hpsvcnb.fc.hp.com (Postfix, from userid 21523) id 8C7FA2CE96; Wed, 24 Aug 2005 12:10:04 -0600 (MDT) To: Carl Baldwin Content-Disposition: inline In-Reply-To: <20050824172339.GA7083@hpsvcnb.fc.hp.com> X-Origin: hpescnb.fc.hp.com User-Agent: Mutt/1.5.9i Sender: git-owner@vger.kernel.org Precedence: bulk X-Mailing-List: git@vger.kernel.org Archived-At: Oops. I forgot to actually exit from the script if git-diff-files is non-empty. Also, looking at it now, I don't think keeping undo information in a stack is the right thing. But keeping more than just one would be good. Oh well, my first shot is never perfect. ;-) Carl On Wed, Aug 24, 2005 at 11:23:39AM -0600, Carl Baldwin wrote: > Hello, > > So, one thing that I liked about GNU Arch when I tried it out was the > ability to undo and redo changes in the local working copy. I decided > to try to do this with git. What I have is preliminary. I'm sure it > could use some work. > > So, I started with the assumption that all changes in the working copy > have been updated to the cache. My scripts check this (with > git-diff-files) and abort if this is not the case. > > Undo calls git-write-tree to write the changes to the object store. It > stores that tree's hash and the current HEAD's tree's hash in a file. > Then it reverts the working copy to HEAD. > > Redo grabs these two trees from the file, does git-write-tree to produce > a third tree and merges the three using the old HEAD's tree as the base > of the merge. This way, new commits can happen and the local copy can > be modified since the undo and it should still work assuming no > conflicts emerge. > > Attached are the two scripts. Comments and criticism are welcome. > > Cheers, > Carl > > -- > - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - > Carl Baldwin Systems VLSI Laboratory > Hewlett Packard Company > MS 88 work: 970 898-1523 > 3404 E. Harmony Rd. work: Carl.N.Baldwin@hp.com > Fort Collins, CO 80525 home: Carl@ecBaldwin.net > - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - > #!/bin/sh > > . git-sh-setup-script || die "Not a git archive" > > if [ -n "$(git-diff-files)" ]; then > echo The following files should be updated! > echo > git-diff-files | awk '{print $6}' > fi > > undostack=$GIT_DIR/undostack > > if [ ! -s $undostack ]; then > echo "No undo information in $undostack" > else > # Read the top of the stack > basetree=$(cat $undostack | tail -n 2 | head -n 1) > redotree=$(cat $undostack | tail -n 1) > > # Pop the stack > cat $undostack | head -n -2 > $undostack.tmp > mv $undostack{.tmp,} > > currenttree=$(git-write-tree) > > git-read-tree -u -m $basetree $currenttree $redotree > git-merge-cache git-merge-one-file-script -a > fi > #!/bin/sh > > . git-sh-setup-script || die "Not a git archive" > > if [ -n "$(git-diff-files)" ]; then > echo The following files should be updated! > echo > git-diff-files | awk '{print $6}' > fi > > undostack=$GIT_DIR/undostack > > headtree=$(git-cat-file commit $(cat $GIT_DIR/HEAD) | head -n 1 | sed -e 's/tree //') > undotree=$(git-write-tree) > > if [ $headtree == $undotree ]; then > echo There are no changes to undo. > else > { > echo $headtree > echo $undotree > } >> $undostack > > echo Saved current state as tree $undotree. > echo Reverting to HEAD, $headtree... > > git-checkout-script -f > fi -- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Carl Baldwin Systems VLSI Laboratory Hewlett Packard Company MS 88 work: 970 898-1523 3404 E. Harmony Rd. work: Carl.N.Baldwin@hp.com Fort Collins, CO 80525 home: Carl@ecBaldwin.net - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -