• Jeff King's avatar
    add generic most-recently-used list · 002f206f
    Jeff King authored
    There are a few places in Git that would benefit from a fast
    most-recently-used cache (e.g., the list of packs, which we
    search linearly but would like to order based on locality).
    This patch introduces a generic list that can be used to
    store arbitrary pointers in most-recently-used order.
    The implementation is just a doubly-linked list, where
    "marking" an item as used moves it to the front of the list.
    Insertion and marking are O(1), and iteration is O(n).
    There's no lookup support provided; if you need fast
    lookups, you are better off with a different data structure
    in the first place.
    There is also no deletion support. This would not be hard to
    do, but it's not necessary for handling pack structs, which
    are created and never removed.
    Signed-off-by: default avatarJeff King <peff@peff.net>
    Signed-off-by: default avatarJunio C Hamano <gitster@pobox.com>
mru.c 968 Bytes