[RFC/PATCH 00/10] vcs-svn: prepare for (implement?) incremental import

Hi,

Using David's "ls" command we can eliminate the in-memory repo_tree and rely on the target repository for information about old revs. This means all state that needs to persist between svn-fe runs is either in the target repo or in the marks file, so in theory this should allow incremental imports already (I haven't tried it).

Caveats:

Not split up as nicely as it ought to be. In particular, the last patch should be split up at least into one patch to modify git fast-import, another for the vcs-svn lib. Perhaps it could be split finer than that.

There is a potential deadlock, marked with NEEDSWORK.

Error checking is not so great. Error states tend to result in deadlock rather than a nicer error.

In particular, we have no way to distinguish between a missing (nonsense) path and an empty directory.

There's a little blind alley in the first few patches --- cat_mark and the function to apply deltas to an old rev do not survive to the end of the series. I kept that because (1) I am lazy and (2) it serves as a quick intro to use of the "ls" command.

Probably there are all sorts of bugs and unclear code. I haven't tested beyond running the test suite.

You can find the series alone at

	git://repo.or.cz/git/jrn.git refs/topics/db/vcs-svn-incremental

and merged with other topics at

	git://repo.or.cz/git/jrn.git vcs-svn-pu

Requires the db/text-delta and db/fast-import-blob-access topics, available from the same place.

Any thoughts would be welcome.

Jonathan Nieder (10):
  vcs-svn: use higher mark numbers for blobs
  vcs-svn: save marks for imported commits
  vcs-svn: introduce cat_mark function to retrieve a marked blob
  vcs-svn: make apply_delta caller retrieve preimage
  vcs-svn: split off function to export result from delta application
  vcs-svn: do not rely on marks for old blobs
  vcs-svn: split off function to make 'ls' requests
  vcs-svn: prepare to eliminate repo_tree structure
  vcs-svn: simplifications for repo_modify_path et al
  vcs-svn: eliminate repo_tree structure

 cache.h               |    2 +
 fast-import.c         |   42 +++++--
 t/t9010-svn-fe.sh     |   55 +++++----
 vcs-svn/fast_export.c |  168 +++++++++++++++++++------
 vcs-svn/fast_export.h |   22 +++-
 vcs-svn/repo_tree.c   |  333 ++++---------------------------------------------
 vcs-svn/repo_tree.h   |    6 +-
 vcs-svn/string_pool.c |    2 +-
 vcs-svn/string_pool.h |    2 +-
 vcs-svn/svndump.c     |   89 +++++++++----
 10 files changed, 301 insertions(+), 420 deletions(-)