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Re: [PATCH 30/33] tree-diff: convert diff_tree_paths to struct object_id

From
Jeff King <peff@peff.net>
Date
May 31, 2017, 21:29 UTC
Message-ID
<20170531212920.yy3swp732rjfnzge@sigill.intra.peff.net>
In-Reply-To
<CAGZ79kZjVvk8GoUFMnR7XJMDyvjkKPhw_7kUYPFq_ShcW50pVQ@mail.gmail.com>
On Wed, May 31, 2017 at 11:24:33AM -0700, Stefan Beller wrote:
Show 32 quoted lines
> On Tue, May 30, 2017 at 10:31 AM, Brandon Williams <bmwill@google.com> wrote:
> >
> > Signed-off-by: Brandon Williams <bmwill@google.com>
> > ---
> >  combine-diff.c | 10 +++++-----
> >  diff.h         |  4 ++--
> >  tree-diff.c    | 63 +++++++++++++++++++++++++++++-----------------------------
> >  3 files changed, 39 insertions(+), 38 deletions(-)
> >
> > diff --git a/combine-diff.c b/combine-diff.c
> > index 04c4ae856..ec9d93044 100644
> > --- a/combine-diff.c
> > +++ b/combine-diff.c
> > @@ -1364,22 +1364,22 @@ static struct combine_diff_path *find_paths_multitree(
> >         struct diff_options *opt)
> >  {
> >         int i, nparent = parents->nr;
> > -       const unsigned char **parents_sha1;
> > +       const struct object_id **parents_oid;
> >         struct combine_diff_path paths_head;
> >         struct strbuf base;
> >
> > -       ALLOC_ARRAY(parents_sha1, nparent);
> > +       ALLOC_ARRAY(parents_oid, nparent);
> >         for (i = 0; i < nparent; i++)
> > -               parents_sha1[i] = parents->oid[i].hash;
> > +               parents_oid[i] = &parents->oid[i];
> 
> I have the impression that we could get away with one layer less
> of indirection. Previously we had a heap allocated array (*) of (char*),
> now we'd have a an array (*) of pointers(*) of the oid struct, that
> is a (char[]) essentially. Maybe I am just confused?

I don't think so. We always could have allocated the original as an array of 20-byte chunks. It's syntactically less awkward in C when that 20-byte chunk is wrapped in a struct like object_id. But fundamentally I think we don't need to be making a copy of the oid. We're pointing to the existing copy in the "parents" array.

Or did you mean that diff_tree_paths() could now take an actual array-of-struct rather than an array-of-pointer-to-struct? That would drop the "parents_oid" array entirely. I think that's actually orthogonal to this change (the same could have been done with the original sha1 array), but would be a nice cleanup on top.

-Peff
Previous: Stefan BellerNext: Jeff King
Message 28 of 66 in “object id conversion (grep and diff)”
  1. 00/33 object id conversion (grep and diff)Brandon Williams, May 30, 2017
  2. 01/33 notes: convert internal structures to struct object_idBrandon Williams, May 30, 2017
  3. 03/33 notes: convert for_each_note to struct object_idBrandon Williams, May 30, 2017
  4. 05/33 notes: convert format_display_notes to struct object_idBrandon Williams, May 30, 2017
  5. 06/33 builtin/notes: convert to struct object_idBrandon Williams, May 30, 2017
  6. 02/33 notes: convert internal parts to struct object_idBrandon Williams, May 30, 2017
  7. 04/33 notes: make get_note return pointer to struct object_idBrandon Williams, May 30, 2017
  8. René ScharfeJul 15, 2017
  9. Brandon WilliamsJul 17, 2017
  10. 09/33 diff: convert get_stat_data to struct object_idBrandon Williams, May 30, 2017
  11. 07/33 notes: convert some accessor functions to struct object_idBrandon Williams, May 30, 2017
  12. 08/33 grep: convert to struct object_idBrandon Williams, May 30, 2017
  13. Junio C HamanoJun 2, 2017
  14. 15/33 diff: convert reuse_worktree_file to struct object_idBrandon Williams, May 30, 2017
  15. 10/33 diff: convert diff_index_show_file to struct object_idBrandon Williams, May 30, 2017
  16. 19/33 combine-diff: convert diff_tree_combined to struct object_idBrandon Williams, May 30, 2017
  17. 14/33 diff: convert fill_filespec to struct object_idBrandon Williams, May 30, 2017
  18. 21/33 tree-diff: convert diff_root_tree_sha1 to struct object_idBrandon Williams, May 30, 2017
  19. 24/33 notes-merge: convert find_notes_merge_pair_ps to struct object_idBrandon Williams, May 30, 2017
  20. 18/33 diff: convert diff_flush_patch_id to struct object_idBrandon Williams, May 30, 2017
  21. 25/33 notes-merge: convert verify_notes_filepair to struct object_idBrandon Williams, May 30, 2017
  22. Stefan BellerMay 31, 2017
  23. Junio C HamanoJun 2, 2017
  24. Brandon WilliamsJun 2, 2017
  25. Junio C HamanoJun 2, 2017
  26. 30/33 tree-diff: convert diff_tree_paths to struct object_idBrandon Williams, May 30, 2017
  27. Stefan BellerMay 31, 2017
  28. Jeff KingMay 31, 2017
  29. Jeff KingMay 31, 2017
  30. Junio C HamanoJun 2, 2017
  31. René ScharfeJul 15, 2017
  32. brian m. carlsonJul 15, 2017
  33. 26/33 notes-merge: convert write_note_to_worktree to struct object_idBrandon Williams, May 30, 2017
  34. 29/33 tree-diff: convert try_to_follow_renames to struct object_idBrandon Williams, May 30, 2017
  35. 20/33 combine-diff: convert find_paths_* to struct object_idBrandon Williams, May 30, 2017
  36. Stefan BellerMay 31, 2017
  37. Junio C HamanoJun 2, 2017
  38. 23/33 notes-merge: convert merge_from_diffs to struct object_idBrandon Williams, May 30, 2017
  39. Stefan BellerMay 31, 2017
  40. Junio C HamanoJun 2, 2017
  41. 22/33 notes-merge: convert notes_merge* to struct object_idBrandon Williams, May 30, 2017
  42. Stefan BellerMay 31, 2017
  43. brian m. carlsonMay 31, 2017
  44. Junio C HamanoJun 2, 2017
  45. Brandon WilliamsJun 2, 2017
  46. 33/33 diff: rename diff_fill_sha1_info to diff_fill_oid_infoBrandon Williams, May 30, 2017
  47. 31/33 tree-diff: convert path_appendnew to object_idBrandon Williams, May 30, 2017
  48. Junio C HamanoJun 2, 2017
  49. 27/33 diff-tree: convert diff_tree_sha1 to struct object_idBrandon Williams, May 30, 2017
  50. 32/33 diffcore-rename: use is_empty_blob_oidBrandon Williams, May 30, 2017
  51. 28/33 builtin/diff-tree: cleanup references to sha1Brandon Williams, May 30, 2017
  52. Junio C HamanoJun 2, 2017
  53. 17/33 patch-ids: convert to struct object_idBrandon Williams, May 30, 2017
  54. 16/33 diff: finish conversion for prepare_temp_file to struct object_idBrandon Williams, May 30, 2017
  55. Stefan BellerMay 31, 2017
  56. 11/33 diff: convert diff_addremove to struct object_idBrandon Williams, May 30, 2017
  57. 12/33 diff: convert run_diff_files to struct object_idBrandon Williams, May 30, 2017
  58. 13/33 diff: convert diff_change to struct object_idBrandon Williams, May 30, 2017
  59. brian m. carlsonMay 31, 2017
  60. Brandon WilliamsJun 2, 2017
  61. Junio C HamanoJun 2, 2017
  62. Junio C HamanoJun 2, 2017
  63. Junio C HamanoJun 2, 2017
  64. Brandon WilliamsJun 2, 2017
  65. Junio C HamanoJun 2, 2017
  66. Brandon WilliamsJun 5, 2017

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