some ideas

[git.ikiwiki.info.git] / doc / about_rcs_backends.mdwn

diff --git a/doc/about_rcs_backends.mdwn b/doc/about_rcs_backends.mdwn
index 85468bc7c802a734257c62fa738373216bff600f..d1454bdda5d58421d4acb7062708e8ec4b1e5d04 100644 (file)
--- a/doc/about_rcs_backends.mdwn
+++ b/doc/about_rcs_backends.mdwn
@@ -1,4 +1,6 @@
-# A few bits about the RCS backends
+A few bits about the RCS backends
+
+[[toc ]]

 
 ## Terminology
 
 
 ## Terminology
 


@@ -31,7 +33,8 @@ You browse and web-edit the wiki on W.
 ## [darcs](http://darcs.net/) (not yet included)
 
 Support for using darcs as a backend is being worked on by [Thomas
 ## [darcs](http://darcs.net/) (not yet included)
 
 Support for using darcs as a backend is being worked on by [Thomas

-Schwinge](mailto:tschwinge@gnu.org).
+Schwinge](mailto:tschwinge@gnu.org), although development is on hold curretly.
+There is a patch in the [[patchqueue]].

 
 ### How will it work internally?
 
 
 ### How will it work internally?
 


@@ -75,6 +78,30 @@ off from R1.
 
 (To be continued.)
 
 
 (To be continued.)
 

+#### Another possible approach
+
+Here's what I (tuomov) think, would be a “cleaner” approach:
+
+ 1. Upon starting to edit, Ikiwiki gets a copy of the page, and `darcs changes --context`.
+     This context _and_ the present version of the page are stored in as the “version” of the
+     page in a hidden control of the HTML.
+     Thus the HTML includes all that is needed to generate a patch wrt. to the state of the
+     repository at the time the edit was started. This is of course all that darcs needs.
+ 2. Once the user is done with editing, _Ikiwiki generates a patch bundle_ for darcs.
+     This should be easy with existing `Text::Diff` or somesuch modules, as the Web edits
+     only concern single files. The reason why the old version of the page is stored in
+     the HTML (possibly compressed) is that the diff can be generated.
+ 3. Now this patch bundle is applied with `darcs apply`, or sent by email for moderation…
+     there are many possibilities.
+
+This approach avoids some of the problems of concurrent edits that the previous one may have,
+although there may be conflicts, which may or may not propagate to the displayed web page.
+(Unfortunately there is not an option to `darcs apply` to generate some sort of ‘confliction resolution
+bundle’.) Also, only one repository is needed, as it is never directly modified
+by Ikiwiki. 
+
+This approach might be applicable to other distributed VCSs as well, although they're not as oriented
+towards transmitting changes with standalone patch bundles (often by email) as darcs is.

 
 ## [[Git]]
 
 
 ## [[Git]]
 


@@ -91,8 +118,48 @@ part).  GIT doesn't have a similar functionality like 'svn merge -rOLD:NEW
 FILE' (please see the relevant comment in mergepast for more details), so I
 had to invent an ugly hack just for the purpose.
 
 FILE' (please see the relevant comment in mergepast for more details), so I
 had to invent an ugly hack just for the purpose.
 

-## [mercurial](http://www.selenic.com/mercurial/)
+By design, Git backend uses a "master-clone" repository pair approach in contrast
+to the single repository approach (here, _clone_ may be considered as the working
+copy of a fictious web user).  Even though a single repository implementation is
+possible, it somewhat increases the code complexity of backend (I couldn't figure
+out a uniform method which doesn't depend on the prefered repository model, yet).
+By exploiting the fact that the master repo and _web user_'s repo (`srcdir`) are all
+on the same local machine, I suggest to create the latter with the "`git clone -l -s`"
+command to save disk space.
+
+Note that, as a rule of thumb, you should always put the rcs wrapper (`post-update`)
+into the master repository (`.git/hooks/`) as can be noticed in the Git wrappers of
+the sample [[ikiwiki.setup]].
+
+## [[Mercurial]]
+
+The Mercurial backend is still in a early phase, so it may not be mature 
+enough, but it should be simple to understand and use.
+
+As Mercurial is a distributed RCS, it lacks the distinction between 
+repository and working copy (every wc is a repo).
+
+This means that the Mercurial backend uses directly the repository as 
+working copy (the master M and the working copy W described in the svn 
+example are the same thing).
+
+You only need to specify 'srcdir' (the repository M) and 'destdir' (where
+the HTML will be generated).
+
+Master repository M.
+
+RCS commit from the outside are installed into M.
+
+M is directly used as working copy (M is also W).
+
+HTML is generated from the working copy in M. rcs_update() will update 
+to the last committed revision in M (the same as 'hg update').
+If you use an 'update' hook you can generate automatically the HTML
+in the destination directory each time 'hg update' is called.
+
+CGI operates on M. rcs_commit() will commit directly in M.

 
 

-Being worked on by Emanuele Aina.
+If you have any question or suggestion about the Mercurial backend 
+please refer to [Emanuele](http://nerd.ocracy.org/em/)

 
 

-<http://techn.ocracy.org/ikiwiki>
+## [[tla]]