rhg: Reuse manifest when checking status of multiple ambiguous files When `rhg status` cannot determine whether a file is clean based on mtime and size alone, it needs to compare its contents with those found in the parent commit. Previously, rhg would find the (same) manifest of that commit again for every such file. This is lifted out of the loop and reused. Differential Revision: https://phab.mercurial-scm.org/D11411

rust: Return HgError instead of RevlogError in revlog constructors This leaves fewer cases for callers to handle, as RevlogError is more general Differential Revision: https://phab.mercurial-scm.org/D11410

rhg: Align with Python on some revset parsing corner cases In particular: * A string of ASCII digits can be either an integer on a hex prefix * The NULL node ID should convert to the NULL revision number Differential Revision: https://phab.mercurial-scm.org/D11409

rust: Add a Filelog struct that wraps Revlog Some filelog-specific logic is moved from code `rhg cat` into this struct where it can better be reused. Additionally, a missing end delimiter for metadata causes an error to be returned instead of being silently ignored. Differential Revision: https://phab.mercurial-scm.org/D11408

rust: Add Repo::manifest(revision) This deduplicates some common code. Differential Revision: https://phab.mercurial-scm.org/D11407

rust: Keep lazily-initialized Changelog and Manifest log on the Repo object That way if one of them is accessed multiple times it won’t be reopened from the filesystem. Differential Revision: https://phab.mercurial-scm.org/D11406

rust: Move lazy initialization of `Repo::dirstate_map` into a generic struct More components of `Repo` will be added following the same pattern. Differential Revision: https://phab.mercurial-scm.org/D11405