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  • Jörg Sonnenberger's avatar
    transaction: change list of journal entries into a dictionary · a985c4fb23ca
    Jörg Sonnenberger authored
    The transaction object used to keep a mapping table of path names to
    journal entries and a list of journal entries consisting of path and
    file offset to truncate on rollback. The offsets are used in three
    cases. repair.strip and rollback process all of them in one go, but they
    care about the order. For them, it is perfectly reasonable to read the
    journal back from disk as both operations already involve at least one
    system call per journal entry. The other consumer is the revlog logic
    for moving from inline to external data storage. It doesn't care about
    the order of the journal and just needs to original offset stored.
    Further optimisations are possible here to move the in-memory journal to
    a set(), but without memoisation of the original revlog size this could
    turn it into O(n^2) behavior in worst case when many revlogs need to
    migrated.
    
    Differential Revision: https://phab.mercurial-scm.org/D9277
    a985c4fb23ca