revlog: use `_format_flags` to access flags instead of `header` It seems better to reuse the variable we carefully extracted This also open the way to more flexible way to retrieve these flags. Differential Revision: https://phab.mercurial-scm.org/D10598

revlog: rename `newversionflags` to `new_header` This make it consistent with the previous changeset. Differential Revision: https://phab.mercurial-scm.org/D10597

revlog: rename `versionflags` to header The variable is named as such because it contains "version" information and "flags" information. However you mostly needs to know the code to understand the name which is not great. The fact that this is the very first four bytes in all revlog seems more relevant, so we rename the variable "header". Differential Revision: https://phab.mercurial-scm.org/D10596

revlog: move index reading logic in a dedicated method They are multiple motivation to do it: * The logic is complicated enough to deserver its own method. * We will need to reuse this once we put a docket in use. * This split the actual reading from the processing of the read data better. Differential Revision: https://phab.mercurial-scm.org/D10595

revlog: define the actual index and datafile at loading time This is just code movement, to make the code closer to where we actually use it and where it will be defined in the future. Differential Revision: https://phab.mercurial-scm.org/D10594

revlog: simplify a conditionnal in _enforceinlinesize This is a gratuitous change to make things a bit easier to read. Differential Revision: https://phab.mercurial-scm.org/D10593

revlog: drop `flush` parameter from `_peek_iscensored` This is not used anywhere. Differential Revision: https://phab.mercurial-scm.org/D10592

revlog: fix error message when data are missing The error message the message was not using the requested offset, but the adjusted offset to that read more data for improved caching. This resulted in confusing error message. Differential Revision: https://phab.mercurial-scm.org/D10591

revlog: rename `nodemap_file` to `_nodemap_file` Same reasoning as for `indexfile and datafile`, lets hide these implementation details. Differential Revision: https://phab.mercurial-scm.org/D10590

revlog: use revlog.display_id in error related to bad revisions Differential Revision: https://phab.mercurial-scm.org/D10589

revlog: use revlog.display_id in "revision too big" errors Differential Revision: https://phab.mercurial-scm.org/D10588

revlog: use revlog.display_id in censor related errors Differential Revision: https://phab.mercurial-scm.org/D10587

revlog: use revlog.display_id in integrity error Differential Revision: https://phab.mercurial-scm.org/D10586

revlog: use revlog.display_id in ambiguity errors Differential Revision: https://phab.mercurial-scm.org/D10585

revlog: use revlog.display_id for corruption error Differential Revision: https://phab.mercurial-scm.org/D10584

revlog: use revlog.display_id in format related errors Differential Revision: https://phab.mercurial-scm.org/D10583

revlog: use revlog.display_id in narrow error message Differential Revision: https://phab.mercurial-scm.org/D10582

revlog: use revlog.display_id in LookupError Differential Revision: https://phab.mercurial-scm.org/D10581

revlog: use revlog.display_id for FilteredLookupError Differential Revision: https://phab.mercurial-scm.org/D10580

revlog: introduce a `display_id` property We currently using the "index file" to identify a revlog in error output. Since we are about to make the "index file" location more volatile, we need something better. We move to use the "radix", as it is close to what we currently use. We could probably do better, as pointed out in the comment, however that would be a quite detour from my current goal. Differential Revision: https://phab.mercurial-scm.org/D10579

revlog: also use radix when computing nodemap data file We have a radix, lets use it! Differential Revision: https://phab.mercurial-scm.org/D10578

revlog: stop usage of `_indexfile` to computing nodemap path We now have the radix explicitely lets use the radix explicitely Differential Revision: https://phab.mercurial-scm.org/D10577

revlog: use a "radix" to address revlog Instead of pointing to the index directly and to derive the other file from that, we directly provide the radix and let the revlog determine the associated file path internally. This is more robust and will give us more flexibility for picking this file name in the future. Differential Revision: https://phab.mercurial-scm.org/D10576

revlog: rename `datafile` to `datafile` We want to make the actual location of the datafile and location more of an implementation details than what is is currently. In that process, we make the attribute private. Differential Revision: https://phab.mercurial-scm.org/D10575