I've been looking at how to convert libsvn_wc to use the pristine store, starting with Hyrum's "#if SVN_EXPERIMENTAL" code in update_editor.c.
STARTING POINT The "#if SVN_EXPERIMENTAL" parts duplicate the storage, storing the new text-base into the new store as well as the old location. There is no code to read from the new store, yet. A NEW TEXT-BASE IS CREATED IN ... add_file_with_history(), apply_textdelta(), svn_wc_add_repos_file4() COMMON FUNCTION TO CREATE A TEMP BASE ... svn_wc__open_writable_base() We should use this function (or something like it) every time we want to write a new pristine file (wc-1 and wc-ng). Then we can do the migration to the WC-NG pristine store inside it. Presently it's used in only one place (apply_textdelta()). I'll change add_file_with_history() to use it as well, if I can. The "need_revert_base" parameter (which determines the exact path of the temp file) can go away, because nothing cares where this temp file is [1]. Evidence that nothing cares: SVN_WC__REVERT_EXT occurs in only 3 other places: svn_wc__text_revert_path() - but that's not looking in the *temporary* area; svn_wc__prop_path - but that's looking for *properties*; upgrade.c:migrate_props(). None of these are relevant, which means nothing can be finding the *revert base* file except by the path that svn_wc__open_writable_base() returns. [1] We mustn't write the temp-revert-base file to WC-1's special temp-normal-base path. I tried, and it caused test failures. Perhaps it overwrites a temp-normal-base that's being used at the same time, or perhaps something looks there and thinks it's found a temp-normal-base and does something with it - I don't know and didn't bother to investigate. I've converted svn_wc__open_writable_base() to use a generic temp dir and unique file name, rather than a WC-1-specific path, and made all three places use it for their WC-1 temp base file, it all still works. OK, that bit works. That's a bit neater. Committed in r919413. Next I can probably move the simultaneous creation of a WC-NG text-base into that function. - Julian
