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Re: [PATCH v2 28/51] refs.c: rename ref_array -> ref_dir

From
Michael Haggerty <mhagger@alum.mit.edu>
Date
Dec 13, 2011, 22:13 UTC
Message-ID
<4EE7CDF2.3040408@alum.mit.edu>
In-Reply-To
<4EE7A387.3070400@alum.mit.edu>
On 12/13/2011 08:12 PM, Michael Haggerty wrote:
Show 20 quoted lines
> On 12/13/2011 07:37 AM, Junio C Hamano wrote:
>> Another possibility is to keep the extra_ref interface in refs.c, without
>> any of your changes (i.e. keep it just as a flat list, with the original
>> interface to append to it without any dedup and other fancy features) and
>> also keep the special casing of it in for_each_ref(). AFAIK, that is the
>> only iterator that should care about the extra refs. Thinking about it a
>> bit more, removal of add_extra_ref() API may be unnecessarily complex with
>> no real gain. For example, extra refs added in builtin/clone.c is used by
>> builtin/fetch-pack.c, meaning that the codepath that discovers and
>> remembers these extra history anchor points and the codepath that uses
>> them while walking the history are not localized and we would need some
>> sort of "extra ref API" anyway. I am leaning towards this option.
> 
> In a few minutes I will post a series of patches that store extra_refs
> in a linked list separate from the reference caches, and iterates over
> them only from for_each_ref().  I could rebase my ref-api-D changes on
> top of this patch series in such a way that the extra refs are kept in
> non-hierarchical storage.  But I leave for vacation on Thursday so it is
> quite likely that I won't be able to get it finished before I return in
> the new year.

I forgot to mention that I think it would be better to separate the handling of extra refs even more than do the patches

    [PATCH 0/6] Handle extra_refs separately from ref_caches

Namely, we should figure out what code wants to set extra refs and or wants to include extra refs in its iteration over references. The setters don't have to be changed, but the readers should be. After the above patch series, the readers call for_each_ref(), which always calls do_for_each_extra_ref(). The call to do_for_each_extra_ref() should be taken out of for_each_ref() and called directly by any readers who want to support extra_refs. Other readers should only call for_each_ref(). (do_for_each_extra_ref(), probably under a different name, would have to become public.) That way, for_each_ref() could ignore the extra refs entirely, and other callers of for_each_ref() wouldn't risk getting extra refs by accident.

Today I spent some time trying to figure out what callers of for_each_ref() could possible want to deal with extra refs, but I got lost in the deep call trees and undocumented function declarations. At the top it is pretty clear that all such code paths start in cmd_clone() or cmd_receive_pack(). But there are so many calls to the for_each_ref*() family of functions that I wasn't able to determine exactly which should allow for extra refs and which shouldn't. (I even wonder whether extra refs might be used inadvertently in some places where they aren't wanted, for example in one of the myriad calls to setup_revisions().) If somebody could put his finger on the for_each_ref() callers who want to support extra refs, that would be very helpful.

Michael
-- 
Michael Haggerty
mhagger@alum.mit.edu
http://softwareswirl.blogspot.com/
Previous: Junio C HamanoNext: Junio C Hamano
Message 44 of 79 in “ref-api-C and ref-api-D re-roll”
  1. 00/51 ref-api-C and ref-api-D re-rollmhagger@alum.mit.edu, Dec 12, 2011
  2. 01/51 struct ref_entry: document name membermhagger@alum.mit.edu, Dec 12, 2011
  3. 02/51 refs: rename "refname" variablesmhagger@alum.mit.edu, Dec 12, 2011
  4. Junio C HamanoDec 13, 2011
  5. 03/51 refs: rename parameters result -> sha1mhagger@alum.mit.edu, Dec 12, 2011
  6. 04/51 clear_ref_array(): rename from free_ref_array()mhagger@alum.mit.edu, Dec 12, 2011
  7. 05/51 is_refname_available(): remove the "quiet" argumentmhagger@alum.mit.edu, Dec 12, 2011
  8. 06/51 parse_ref_line(): add docstringmhagger@alum.mit.edu, Dec 12, 2011
  9. 07/51 add_ref(): add docstringmhagger@alum.mit.edu, Dec 12, 2011
  10. 08/51 is_dup_ref(): extract function from sort_ref_array()mhagger@alum.mit.edu, Dec 12, 2011
  11. Jeff KingDec 12, 2011
  12. Michael HaggertyDec 12, 2011
  13. Junio C HamanoDec 12, 2011
  14. Junio C HamanoDec 12, 2011
  15. Michael HaggertyDec 13, 2011
  16. Michael HaggertyDec 13, 2011
  17. 09/51 refs: change signatures of get_packed_refs() and get_loose_refs()mhagger@alum.mit.edu, Dec 12, 2011
  18. 10/51 get_ref_dir(): change signaturemhagger@alum.mit.edu, Dec 12, 2011
  19. 11/51 resolve_gitlink_ref(): improve docstringmhagger@alum.mit.edu, Dec 12, 2011
  20. 12/51 Pass a (ref_cache *) to the resolve_gitlink_*() helper functionsmhagger@alum.mit.edu, Dec 12, 2011
  21. 13/51 resolve_gitlink_ref_recursive(): change to work with struct ref_cachemhagger@alum.mit.edu, Dec 12, 2011
  22. 14/51 repack_without_ref(): remove temporarymhagger@alum.mit.edu, Dec 12, 2011
  23. 15/51 create_ref_entry(): extract function from add_ref()mhagger@alum.mit.edu, Dec 12, 2011
  24. 16/51 add_ref(): take a (struct ref_entry *) parametermhagger@alum.mit.edu, Dec 12, 2011
  25. 17/51 do_for_each_ref(): correctly terminate while processesing extra_refsmhagger@alum.mit.edu, Dec 12, 2011
  26. Junio C HamanoDec 12, 2011
  27. 18/51 do_for_each_ref_in_array(): new functionmhagger@alum.mit.edu, Dec 12, 2011
  28. 19/51 do_for_each_ref_in_arrays(): new functionmhagger@alum.mit.edu, Dec 12, 2011
  29. 20/51 repack_without_ref(): reimplement using do_for_each_ref_in_array()mhagger@alum.mit.edu, Dec 12, 2011
  30. Junio C HamanoDec 12, 2011
  31. 21/51 names_conflict(): new function, extracted from is_refname_available()mhagger@alum.mit.edu, Dec 12, 2011
  32. 22/51 names_conflict(): simplify implementationmhagger@alum.mit.edu, Dec 12, 2011
  33. 23/51 is_refname_available(): reimplement using do_for_each_ref_in_array()mhagger@alum.mit.edu, Dec 12, 2011
  34. 24/51 refs.c: reorder definitions more logicallymhagger@alum.mit.edu, Dec 12, 2011
  35. 25/51 free_ref_entry(): new functionmhagger@alum.mit.edu, Dec 12, 2011
  36. 26/51 check_refname_component(): return 0 for zero-length componentsmhagger@alum.mit.edu, Dec 12, 2011
  37. 27/51 struct ref_entry: nest the value part in a unionmhagger@alum.mit.edu, Dec 12, 2011
  38. 28/51 refs.c: rename ref_array -> ref_dirmhagger@alum.mit.edu, Dec 12, 2011
  39. Junio C HamanoDec 13, 2011
  40. Michael HaggertyDec 13, 2011
  41. Junio C HamanoDec 13, 2011
  42. Michael HaggertyDec 13, 2011
  43. Junio C HamanoDec 13, 2011
  44. Michael HaggertyDec 13, 2011
  45. Junio C HamanoDec 13, 2011
  46. Junio C HamanoDec 14, 2011
  47. Jeff KingDec 14, 2011
  48. Michael HaggertyDec 15, 2011
  49. Jeff KingDec 15, 2011
  50. Michael HaggertyJan 17, 2012
  51. Michael HaggertyFeb 10, 2012
  52. Jeff KingFeb 10, 2012
  53. Junio C HamanoFeb 10, 2012
  54. Michael HaggertyFeb 11, 2012
  55. 29/51 refs: store references hierarchicallymhagger@alum.mit.edu, Dec 12, 2011
  56. 30/51 sort_ref_dir(): do not sort if already sortedmhagger@alum.mit.edu, Dec 12, 2011
  57. Junio C HamanoDec 12, 2011
  58. 31/51 refs: sort ref_dirs lazilymhagger@alum.mit.edu, Dec 12, 2011
  59. 32/51 do_for_each_ref(): only iterate over the subtree that was requestedmhagger@alum.mit.edu, Dec 12, 2011
  60. 33/51 get_ref_dir(): keep track of the current ref_dirmhagger@alum.mit.edu, Dec 12, 2011
  61. 34/51 refs: wrap top-level ref_dirs in ref_entriesmhagger@alum.mit.edu, Dec 12, 2011
  62. 35/51 get_packed_refs(): return (ref_entry *) instead of (ref_dir *)mhagger@alum.mit.edu, Dec 12, 2011
  63. 36/51 get_loose_refs(): return (ref_entry *) instead of (ref_dir *)mhagger@alum.mit.edu, Dec 12, 2011
  64. 37/51 is_refname_available(): take (ref_entry *) instead of (ref_dir *)mhagger@alum.mit.edu, Dec 12, 2011
  65. 38/51 find_ref(): take (ref_entry *) instead of (ref_dir *)mhagger@alum.mit.edu, Dec 12, 2011
  66. 39/51 read_packed_refs(): take (ref_entry *) instead of (ref_dir *)mhagger@alum.mit.edu, Dec 12, 2011
  67. 40/51 add_ref(): take (ref_entry *) instead of (ref_dir *)mhagger@alum.mit.edu, Dec 12, 2011
  68. 41/51 find_containing_direntry(): use (ref_entry *) instead of (ref_dir *)mhagger@alum.mit.edu, Dec 12, 2011
  69. 42/51 search_ref_dir(): take (ref_entry *) instead of (ref_dir *)mhagger@alum.mit.edu, Dec 12, 2011
  70. 43/51 add_entry(): take (ref_entry *) instead of (ref_dir *)mhagger@alum.mit.edu, Dec 12, 2011
  71. 44/51 do_for_each_ref_in_dir*(): take (ref_entry *) instead of (ref_dir *)mhagger@alum.mit.edu, Dec 12, 2011
  72. 45/51 sort_ref_dir(): take (ref_entry *) instead of (ref_dir *)mhagger@alum.mit.edu, Dec 12, 2011
  73. 46/51 struct ref_dir: store a reference to the enclosing ref_cachemhagger@alum.mit.edu, Dec 12, 2011
  74. 47/51 read_loose_refs(): take a (ref_entry *) as argumentmhagger@alum.mit.edu, Dec 12, 2011
  75. 48/51 refs: read loose references lazilymhagger@alum.mit.edu, Dec 12, 2011
  76. 49/51 is_refname_available(): query only possibly-conflicting referencesmhagger@alum.mit.edu, Dec 12, 2011
  77. 50/51 read_packed_refs(): keep track of the directory being worked inmhagger@alum.mit.edu, Dec 12, 2011
  78. 51/51 repack_without_ref(): call clear_packed_ref_cache()mhagger@alum.mit.edu, Dec 12, 2011
  79. Junio C HamanoDec 12, 2011

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