revlog: rename `indexfile` to `_indexfile` We want to make the actual location of the indexfile 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/D10574

filelog: drop `indexfile` from `filelog` Since `filelog` objects are not revlog (no really, they are not…) we drop the revlog specific attribute. We need to directly access the underlying revlog in a couple of place that already assume that we have a revlog here. This is motivated by future change to that revlog attribute. Differential Revision: https://phab.mercurial-scm.org/D10573

manifest: drop the `indexfile` from `manifestrevlog` Since `manifestrevlog` object are not revlog (no really, they are not…) we drop the revlog specific attribute. We need to directly access the underlying revlog in a couple of place that already assume that we have a revlog here. This is motivated by future change to that revlog attribute. Differential Revision: https://phab.mercurial-scm.org/D10572

revlog: deal with special "postfix" explicitely revlog usually use a straight forward '.i' and '.d' naming except for two cases "in-transaction" changelog, and censoring. Our goal is to let the revlog code deal with the internal of the file naming itself. To do so, we need to start dealing with these postfix explicitly. Differential Revision: https://phab.mercurial-scm.org/D10571

revlog: split the option initialisation in its own method The part of the code is huge, keeping it separated will keep the `_loadindex` method simpler and help keeping logic well insulated. Differential Revision: https://phab.mercurial-scm.org/D10570

revlog: always "append" full size tuple Same reasoning as the previous patch. Differential Revision: https://phab.mercurial-scm.org/D10569

revlog: make the index always return the same tuple It is simpler to manage the diferrence in on disk format in the internal index code itself and lets the rest of the code always handle the same object. This will become even more important when the data we store will be entirely different (for example the changelog does not need the "linkrev" field. We start with item reading, we will deal with item writing in the next changesets. Differential Revision: https://phab.mercurial-scm.org/D10568

revlog: introduce an explicit `format_version` member in the index struct This will allow for cleaner check than assuming each version has a different size. Unsurprisingly I am planning to use this to introduce more format variant. Differential Revision: https://phab.mercurial-scm.org/D10567

revlog: rename `hdrsize` to `entry_size` in the C code This is the size of and index entry, so lets make it clearer. Differential Revision: https://phab.mercurial-scm.org/D10566

revlog: split the `version` attribute into its two components The `revlog.version` attribute contained an integer coding 2 different informations: * the revlog version number * a bit field defining some specific feature of the revlog We now explicitly store the two components independently. This avoid exposing the implementation details all around the code and prepare for future revlog version that would encode the information in a different way. In the process we drop the `version` attribute from the interface. It was flagged for removal when that interface was created. Differential Revision: https://phab.mercurial-scm.org/D10565