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Re: [PATCH 8/8] diff: improve positioning of add/delete blocks in diffs

From
Junio C Hamano <gitster@pobox.com>
Date
Aug 10, 2016, 21:28 UTC
Message-ID
<xmqq8tw448lh.fsf@gitster.mtv.corp.google.com>
In-Reply-To
<5fe0edbc-3659-058f-3328-639d1343fa05@alum.mit.edu>
Michael Haggerty <mhagger@alum.mit.edu> writes:
Show 16 quoted lines
>> After
>> all, somebody in this file is already scanning each and every line
>> to see where it ends to split the input into records, so perhaps a
>> "right" (if the "theoretical correctness" of the return value from
>> this function mattered, which you wave-away below) optimization
>> could be to precompute it while the lines are broken into records
>> and store it in the "rec" structure?
>
> That would certainly be possible, and would help in cases where there
> are a lot of lines with lots of leading whitespace. You could get nearly
> the same benefit by recording a single bit in struct rec, indicating
> whether the line is blank or not.
>
> But it wouldn't help the worst case described above, where each call to
> `git_indent()` is already very cheap. And I didn't think it was worth
> allocating the extra memory to optimize this heuristic
True.
> I don't know. It seems like a pretty contrived justification for what is
> basically, "your input is too weird for us. We're not going to break our
> necks trying to give you the best possible slider positioning."
True again.
Previous: Michael HaggertyNext: Stefan Beller
Message 36 of 57 in “Better heuristics make prettier diffs”
  1. 0/8 Better heuristics make prettier diffsMichael Haggerty, Aug 3, 2016
  2. 2/8 xdl_change_compact(): clarify codeMichael Haggerty, Aug 3, 2016
  3. Stefan BellerAug 3, 2016
  4. Michael HaggertyAug 3, 2016
  5. Stefan BellerAug 3, 2016
  6. Jeff KingAug 4, 2016
  7. Michael HaggertyAug 10, 2016
  8. Stefan BellerAug 10, 2016
  9. 5/8 xdl_change_compact(): fix compaction heuristic to adjust ioMichael Haggerty, Aug 3, 2016
  10. Jeff KingAug 4, 2016
  11. Michael HaggertyAug 10, 2016
  12. Michael HaggertyAug 10, 2016
  13. Jeff KingAug 11, 2016
  14. Junio C HamanoAug 4, 2016
  15. Michael HaggertyAug 10, 2016
  16. 7/8 is_blank_line: take a single xrecord_t as argumentMichael Haggerty, Aug 3, 2016
  17. Junio C HamanoAug 4, 2016
  18. 6/8 xdl_change_compact(): keep track of the earliest endMichael Haggerty, Aug 3, 2016
  19. Junio C HamanoAug 4, 2016
  20. Michael HaggertyAug 10, 2016
  21. 4/8 xdl_change_compact(): do one final shift or the other, not bothMichael Haggerty, Aug 3, 2016
  22. 1/8 xdl_change_compact(): rename some local variables for clarityMichael Haggerty, Aug 3, 2016
  23. Jeff KingAug 4, 2016
  24. Junio C HamanoAug 4, 2016
  25. Michael HaggertyAug 13, 2016
  26. Jeff KingAug 14, 2016
  27. Michael HaggertyAug 3, 2016
  28. 3/8 xdl_change_compact(): rename i to endMichael Haggerty, Aug 3, 2016
  29. Jeff KingAug 4, 2016
  30. 8/8 diff: improve positioning of add/delete blocks in diffsMichael Haggerty, Aug 3, 2016
  31. Jacob KellerAug 3, 2016
  32. Michael HaggertyAug 3, 2016
  33. Jacob KellerAug 4, 2016
  34. Junio C HamanoAug 4, 2016
  35. Michael HaggertyAug 10, 2016
  36. Junio C HamanoAug 10, 2016
  37. Stefan BellerAug 3, 2016
  38. Michael HaggertyAug 3, 2016
  39. Stefan BellerAug 3, 2016
  40. Michael HaggertyAug 3, 2016
  41. Stefan BellerAug 4, 2016
  42. Michael HaggertyAug 10, 2016
  43. Jeff KingAug 4, 2016
  44. Stefan BellerAug 4, 2016
  45. Junio C HamanoAug 4, 2016
  46. Michael HaggertyAug 13, 2016
  47. Michael HaggertyAug 12, 2016
  48. Jeff KingAug 13, 2016
  49. Junio C HamanoAug 13, 2016
  50. Jacob KellerAug 14, 2016
  51. Stefan BellerAug 15, 2016
  52. Junio C HamanoAug 15, 2016
  53. Junio C HamanoAug 4, 2016
  54. Michael HaggertyAug 13, 2016
  55. Jeff KingAug 4, 2016
  56. Junio C HamanoAug 4, 2016
  57. Jeff KingAug 4, 2016

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