ref_array: keep track of whether references are sorted
Keep track of how many entries at the beginning of a ref_array are already sorted. In sort_ref_array(), return early if the the array is already sorted (i.e., if no new references has been appended to the end of the list since the last call to sort_ref_array()). Sort ref_arrays only when needed, namely in search_ref_array() and in do_for_each_ref(). However, never call sort_ref_array() on the extra_refs, because extra_refs can contain multiple entries with the same name and because sort_ref_array() not only sorts, but de-dups its contents. This change is currently not useful, because entries are not added to ref_arrays after they are created. But in a moment they will be... Implementation note: we could store a binary "sorted" value instead of an integer, but storing the number of sorted entries leaves the way open for a couple of possible future optimizations: * In sort_ref_array(), sort *only* the unsorted entries, then merge them with the sorted entries. This should be faster if most of the entries are already sorted. * Teach search_ref_array() to do a binary search of any sorted entries, and if unsuccessful do a linear search of any unsorted entries. This would avoid the need to sort the list every time that search_ref_array() is called, and (given some intelligence about how often to sort) could significantly improve the speed in certain hypothetical usage patterns. Signed-off-by: NMichael Haggerty <mhagger@alum.mit.edu> Signed-off-by: NJunio C Hamano <gitster@pobox.com>
Showing
想要评论请 注册 或 登录