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Re: [PATCH v5 10/35] cache.h: define constants LOCK_SUFFIX and LOCK_SUFFIX_LEN

From
Michael Haggerty <mhagger@alum.mit.edu>
Date
Sep 22, 2014, 15:25 UTC
Message-ID
<54203F5E.5090805@alum.mit.edu>
In-Reply-To
<20140916210538.GK29050@google.com>
On 09/16/2014 11:05 PM, Jonathan Nieder wrote:
Show 8 quoted lines
> Michael Haggerty wrote:
> 
>> There are a few places that use these values, so define constants for
>> them.
> 
> Seems like a symptom of the API leaving out a useful helper (e.g.,
> something that strips off the lock suffix and returns a memdupz'd
> filename).
I will add a function get_locked_file_path().
Show 16 quoted lines
> [...]
>> --- a/cache.h
>> +++ b/cache.h
>> @@ -570,6 +570,10 @@ extern void fill_stat_cache_info(struct cache_entry *ce, struct stat *st);
>>  #define REFRESH_IN_PORCELAIN	0x0020	/* user friendly output, not "needs update" */
>>  extern int refresh_index(struct index_state *, unsigned int flags, const struct pathspec *pathspec, char *seen, const char *header_msg);
>>  
>> +/* String appended to a filename to derive the lockfile name: */
>> +#define LOCK_SUFFIX ".lock"
>> +#define LOCK_SUFFIX_LEN 5
> 
> My suspicion is that error handling would be better if fewer callers
> outside of lockfile.c did the '- LOCK_SUFFIX_LEN' dance, so this seems
> like a step in the wrong direction.
> 
> Adding constants in lockfile.c would make sense, though.

I agree that other call sites shouldn't be grubbing around in the lock_file data structure. But with the addition of get_locked_file_path(), the only remaining user of these constants is in refs.c, in check_refname_component():

	if (cp - refname >= LOCK_SUFFIX_LEN &&
	    !memcmp(cp - LOCK_SUFFIX_LEN, LOCK_SUFFIX, LOCK_SUFFIX_LEN))
		return -1; /* Refname ends with ".lock". */
I think it is forgivable there.
Michael
-- 
Michael Haggerty
mhagger@alum.mit.edu
Previous: Jonathan NiederNext: Michael Haggerty
Message 31 of 73 in “Lockfile correctness and refactoring”
  1. 00/35 Lockfile correctness and refactoringMichael Haggerty, Sep 16, 2014
  2. 01/35 unable_to_lock_die(): rename function from unable_to_lock_index_die()Michael Haggerty, Sep 16, 2014
  3. Jonathan NiederSep 16, 2014
  4. 02/35 api-lockfile: expand the documentationMichael Haggerty, Sep 16, 2014
  5. Jonathan NiederSep 16, 2014
  6. Michael HaggertySep 22, 2014
  7. 03/35 rollback_lock_file(): do not clear filename redundantlyMichael Haggerty, Sep 16, 2014
  8. Jonathan NiederSep 16, 2014
  9. 04/35 rollback_lock_file(): exit early if lock is not activeMichael Haggerty, Sep 16, 2014
  10. Jonathan NiederSep 16, 2014
  11. 05/35 rollback_lock_file(): set fd to -1Michael Haggerty, Sep 16, 2014
  12. Jonathan NiederSep 16, 2014
  13. Jonathan NiederSep 16, 2014
  14. Michael HaggertySep 17, 2014
  15. 06/35 lockfile: unlock file if lockfile permissions cannot be adjustedMichael Haggerty, Sep 16, 2014
  16. Jonathan NiederSep 16, 2014
  17. 07/35 hold_lock_file_for_append(): release lock on errorsMichael Haggerty, Sep 16, 2014
  18. Jonathan NiederSep 16, 2014
  19. Michael HaggertySep 17, 2014
  20. 08/35 lock_file(): always add lock_file object to lock_file_listMichael Haggerty, Sep 16, 2014
  21. Jonathan NiederSep 16, 2014
  22. Michael HaggertySep 17, 2014
  23. Torsten BögershausenSep 18, 2014
  24. Michael HaggertySep 18, 2014
  25. 09/35 lockfile.c: document the various states of lock_file objectsMichael Haggerty, Sep 16, 2014
  26. Jonathan NiederSep 16, 2014
  27. Michael HaggertySep 22, 2014
  28. Jonathan NiederSep 22, 2014
  29. 10/35 cache.h: define constants LOCK_SUFFIX and LOCK_SUFFIX_LENMichael Haggerty, Sep 16, 2014
  30. Jonathan NiederSep 16, 2014
  31. Michael HaggertySep 22, 2014
  32. 11/35 delete_ref_loose(): don't muck around in the lock_file's filenameMichael Haggerty, Sep 16, 2014
  33. Jonathan NiederSep 16, 2014
  34. 12/35 prepare_index(): declare return value to be (const char *)Michael Haggerty, Sep 16, 2014
  35. Jonathan NiederSep 16, 2014
  36. 13/35 write_packed_entry_fn(): convert cb_data into a (const int *)Michael Haggerty, Sep 16, 2014
  37. 14/35 lock_file(): exit early if lockfile cannot be openedMichael Haggerty, Sep 16, 2014
  38. Jonathan NiederSep 16, 2014
  39. 15/35 remove_lock_file(): call rollback_lock_file()Michael Haggerty, Sep 16, 2014
  40. Jonathan NiederSep 16, 2014
  41. 16/35 commit_lock_file(): inline temporary variableMichael Haggerty, Sep 16, 2014
  42. Jonathan NiederSep 16, 2014
  43. 17/35 commit_lock_file(): die() if called for unlocked lockfile objectMichael Haggerty, Sep 16, 2014
  44. Jonathan NiederSep 16, 2014
  45. 18/35 commit_lock_file(): if close fails, roll backMichael Haggerty, Sep 16, 2014
  46. Jonathan NiederSep 16, 2014
  47. Michael HaggertySep 23, 2014
  48. 19/35 commit_lock_file(): rollback lock file on failure to renameMichael Haggerty, Sep 16, 2014
  49. Jonathan NiederSep 16, 2014
  50. Michael HaggertySep 23, 2014
  51. 20/35 api-lockfile: document edge casesMichael Haggerty, Sep 16, 2014
  52. Jonathan NiederSep 16, 2014
  53. Michael HaggertySep 23, 2014
  54. 21/35 dump_marks(): remove a redundant call to rollback_lock_file()Michael Haggerty, Sep 16, 2014
  55. Jonathan NiederSep 16, 2014
  56. 22/35 git_config_set_multivar_in_file(): avoid call to rollback_lock_file()Michael Haggerty, Sep 16, 2014
  57. Jonathan NiederSep 16, 2014
  58. Michael HaggertySep 23, 2014
  59. 23/35 lockfile: avoid transitory invalid statesMichael Haggerty, Sep 16, 2014
  60. Jonathan NiederSep 16, 2014
  61. Michael HaggertySep 23, 2014
  62. 24/35 struct lock_file: declare some fields volatileMichael Haggerty, Sep 16, 2014
  63. 25/35 try_merge_strategy(): remove redundant lock_file allocationMichael Haggerty, Sep 16, 2014
  64. 26/35 try_merge_strategy(): use a statically-allocated lock_file objectMichael Haggerty, Sep 16, 2014
  65. 27/35 commit_lock_file(): use a strbuf to manage temporary spaceMichael Haggerty, Sep 16, 2014
  66. 28/35 Change lock_file::filename into a strbufMichael Haggerty, Sep 16, 2014
  67. 29/35 resolve_symlink(): use a strbuf for internal scratch spaceMichael Haggerty, Sep 16, 2014
  68. 30/35 resolve_symlink(): take a strbuf parameterMichael Haggerty, Sep 16, 2014
  69. 31/35 trim_last_path_component(): replace last_path_elm()Michael Haggerty, Sep 16, 2014
  70. 32/35 Extract a function commit_lock_file_to()Michael Haggerty, Sep 16, 2014
  71. 33/35 Rename LOCK_NODEREF to LOCK_NO_DEREFMichael Haggerty, Sep 16, 2014
  72. 34/35 lockfile.c: rename static functionsMichael Haggerty, Sep 16, 2014
  73. 35/35 get_locked_file_path(): new functionMichael Haggerty, Sep 16, 2014

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