-## A few bits about the RCS backends
+# A few bits about the RCS backends
-### Terminology
+## Terminology
``web-edit'' means that a page is edited by using the web (CGI) interface
as opposed to using a editor and the RCS interface.
-### [[Subversion]]
+## [[Subversion]]
-Subversion was that first RCS to be supported by ikiwiki.
+Subversion was the first RCS to be supported by ikiwiki.
-#### How does it work internally?
+### How does it work internally?
Master repository M.
CGI operates on W. rcs_commit() will commit from W to M.
+For all the gory details of how ikiwiki handles this behind the scenes,
+see [[commit-internals]].
+
You browse and web-edit the wiki on W.
-### [darcs](http://darcs.net/) (not yet included)
+## [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).
-#### How will it work internally?
+### How will it work internally?
``Master'' repository R1.
CGI operates on R2. rcs_commit() will push from R2 to R1.
You browse the wiki on R1 and web-edit it on R2. This means for example
-that R2 needs to be updated from R1 if you are going the web-edit a page,
+that R2 needs to be updated from R1 if you are going to web-edit a page,
as the user otherwise might be irritated otherwise...
How do changes get from R1 to R2? Currently only internally in
-rcs_commit(). Is rcs_prepedit() suitable?
+rcs\_commit(). Is rcs\_prepedit() suitable?
It follows that the HTML rendering and the CGI handling can be completely
separated parts in ikiwiki.
-##### Rationale for doing it differently than in the Subversion case
+What repository should [[RecentChanges]] and [[History]] work on? R1?
+
+#### Rationale for doing it differently than in the Subversion case
darcs is a distributed RCS, which means that every checkout of a
repository is equal to the repository it was checked-out from. There is
no forced hierarchy.
-R1 is the nevertheless called the master repository. It's used for
+R1 is nevertheless called the master repository. It's used for
collecting all the changes and publishing them: on the one hand via the
rendered HTML and on the other via the standard darcs RCS interface.
-R2, the repository where CGI operates on, is just a checkout of R1 and
+R2, the repository the CGI operates on, is just a checkout of R1 and
doesn't really differ from the other checkouts that people will branch
off from R1.
(To be continued.)
+
+
+## [[Git]] (not yet included)
+
+A patch with full [Git](http://git.or.cz) support is at <http://people.debian.org/~roktas/patches/ikiwiki/git.patch>. Regarding the patch, Recai says:
+
+I have been testing it for the past few days and it seems satisfactory. I
+haven't observed any race condition regarding the concurrent blog commits
+and it handles merge conflicts gracefully as far as I can see.
+
+As you may notice from the patch size, GIT support is not so trivial to
+implement (for me, at least). Being a fairly fresh code base it has some
+bugs. It also has some drawbacks (especially wrt merge which was the hard
+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.
+
+Some other notes:
+
+- There are two separate helper packages in git.pm. To keep things self
+ confined, I haven't split it up.
+
+- I've used a (mini) Debug.pm during the tests and made it a separate file
+ for the convenience of others. It relies on the "constant folding"
+ feature of Perl, so there shouldn't be a runtime penalty (at least this
+ is what the 'perl -MO=Deparse shows', haven't made a real benchmark).
+
+- rcs_notify() has not been implemented yet (I have noticed it after I
+ finished the main work).
+
+- GIT backend uses the gitweb for repository browsing (the counterpart of
+ ViewCVS).
+
+- There might be some subs in GIT name space which you may prefer to move to
+ the main code.
+
+- Due to the reasons explained in the code, I've written an rcs_invoke()
+ wrapper. May be there should be a better approach to reach the same
+ goal.
+
+- There are some parts which I may change in future, like using a global
+ rcs_fatal_error and the ugly error reporting code in _rcs_commit.
+
+- Documentation is missing.
+
+It works for me, but of course in the end, the final decision is yours (due
+to mostly GIT quirks, the implementation is not clean as SVN). Feel free
+to fix/delete/add whatever you want. Hope it doesn't have any serious bug.