> URL: http://svn.apache.org/r1446169 > Log: > Following up on r1446118, make the knowledge whether reversed obtaining of > file revisions is available visible by adding an ra capability. > > This to allow a future blame improvement to decide whether it can use an > improved algorithm instead of the current one without waiting for an error > on old servers.
Nice. A few questions. When you first added this "reverse order" functionality in <http://svn.apache.org/r1445973>, you documented for svn_ra_get_file_revs2() and svn_repos_get_file_revs2(): + * On subversion 1.8 and newer servers this function has been enabled + * to support reversion of the revision range for @a include_merged_revision + * @c FALSE reporting by switching @a end with @a start. Is that still the case or do those functions now support a backwards range with merged revisions included? Reference the capability string in those doc strings. There's still a big comment on the definition (rather than declaration) of svn_repos_get_file_revs2() which says reverse ranges are not supported; that should go away or be updated. For testing, in r1445973: * subversion/tests/libsvn_repos/repos-test.c (test_get_file_revs): Extend test to also walk the revisions backwards. Would it be true to say that the results of a reverse range should always be the reversal of the results from the equivalent forward range? If so, that would be a useful test. The current test doesn't appear to verify that the results are in any particular order. More below... > * subversion/include/svn_dav.h > (SVN_DAV_NS_DAV_SVN_ATOMIC_REVPROPS): Move new in 1.7 define below one that > exists in 1.6. > (SVN_DAV_NS_DAV_SVN_INHERITED_PROPS): Mark new in 1.8. > (SVN_DAV_NS_DAV_SVN_EPHEMERAL_TXNPROPS): Mark new in 1.8. > (SVN_DAV_NS_DAV_SVN_INLINE_PROPS): Mark new in 1.8. > (SVN_DAV_NS_DAV_SVN_GET_FILE_REVS_REVERSE): New macro. > > * subversion/include/svn_ra.h > (SVN_RA_CAPABILITY_GET_FILE_REVS_REVERSE): New macro. > > * subversion/include/svn_ra_svn.h > (SVN_RA_SVN_CAP_GET_FILE_REVS_REVERSE): New macro. > > * subversion/libsvn_ra_local/ra_plugin.c > (svn_ra_local__has_capability): Declare support for reversed file > revisions *and* ephemeral txnprops. That's an unrelated change, fixing ra-local to advertise ephemeral txnprops. That's worth drawing attention to, as it indicates we aren't testing that feature. (It would have been better as a separate commit.) > * subversion/libsvn_ra_serf/options.c > (capabilities_headers_iterator_callback): Forward > SVN_RA_SVN_CAP_GET_FILE_REVS_REVERSE support. > > * subversion/libsvn_ra_svn/client.c > (ra_svn_has_capability): Make function table driven. Add > SVN_RA_SVN_CAP_GET_FILE_REVS_REVERSE support. > > * subversion/mod_dav_svn/version.c > (get_vsn_options): Write SVN_DAV_NS_DAV_SVN_GET_FILE_REVS_REVERSE. > > * subversion/svnserve/serve.c > (serve): Send SVN_RA_SVN_CAP_GET_FILE_REVS_REVERSE support. > +/** > + * The capability of a server to walk revisions backwards in > + * svn_ra_get_file_revs2 Doxygen will make this a hyperlink if you add '()' after the function name. > + * > + * @since New in 1.8. > + */ > +#define SVN_RA_CAPABILITY_GET_FILE_REVS_REVERSE "get-file-revs-reversed" > +/** Presence of this in a DAV header in an OPTIONS response indicates > + * that the transmitter (in this case, the server) knows how to handle > + * a reversed fetch of file versions. > + * @since New in 1.8. */ > +#define SVN_DAV_NS_DAV_SVN_GET_FILE_REVS_REVERSE\ > + SVN_DAV_PROP_NS_DAV "svn/get-file-revs-rvrs" > +/* maps to SVN_RA_CAPABILITY_GET_FILE_REVS_REVERSE */ > +#define SVN_RA_SVN_CAP_GET_FILE_REVS_REVERSE "file-revs-reverse" Would it be useful to refer to the relevant DAV/svnserve API functions from these two doc strings? In the doc string of svn_ra_get_file_revs2(), detail what the presence or absence of this capability really means to a caller. Something like: [[[ With a forward range, svn_ra_get_file_revs2() calculates the list of revisions before starting to send them to the caller. When a backward range is requested, with the 'reverse' capability (#SVN_RA_CAPABILITY_GET_FILE_REVS_REVERSE) svn_ra_get_file_revs2() returns the revisions streamily in backward order, but a request for merged revisions throws an error; without the capability, it either throws an error or returns an incomplete result. ]]] - Julian
