[PATCH 0/8] `log -c` speedup (part 2)

Hello up there,

I'm still trying to speedup combined-diff to be not so slow, to be able to realistically use it in my readonly filesystem for git archives.

In the first part[1], we optimized paths intersections, but combined-diff still remained slow, because internally it was computing huge diffs, even for small, or empty output.

This time, here goes paths scanning rework, which results in significant combine-diff speedup. Please apply.

Thanks beforehand, Kirill

P.S. the code depends on ks/diff-c-with-diff-order

[1] http://permalink.gmane.org/gmane.comp.version-control.git/240713

Kirill Smelkov (8):
  fixup! combine_diff: simplify intersect_paths() further
  tests: add checking that combine-diff emits only correct paths
  tree-diff: no need to manually verify that there is no mode change for
    a path
  tree-diff: no need to pass match to skip_uninteresting()
  combine-diff: move show_log_first logic/action out of paths scanning
  combine-diff: Move changed-paths scanning logic into its own function
  combine-diff: Fast changed-to-all-parents paths scanning
  combine-diff: bail out early, if num_paths=0

 combine-diff.c                 | 215 +++++++++++++++-----
 diff.c                         |   1 +
 diff.h                         |   6 +
 t/t4057-diff-combined-paths.sh | 106 ++++++++++
 tree-diff.c                    | 442 +++++++++++++++++++++++++++++++++++++++--
 5 files changed, 696 insertions(+), 74 deletions(-)
 create mode 100755 t/t4057-diff-combined-paths.sh