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Re: [PATCH v2 28/43] refs.c: add ref backend init function

From
Michael Haggerty <mhagger@alum.mit.edu>
Date
Oct 5, 2015, 08:37 UTC
Message-ID
<561236E7.1050508@alum.mit.edu>
In-Reply-To
<1443477738-32023-29-git-send-email-dturner@twopensource.com>
On 09/29/2015 12:02 AM, David Turner wrote:
Show 40 quoted lines
> The file backend doesn't need this function, but other backends might.
> 
> Signed-off-by: David Turner <dturner@twopensource.com>
> Signed-off-by: Ronnie Sahlberg <rsahlberg@google.com>
> ---
>  refs-be-files.c | 1 +
>  refs.c          | 4 +++-
>  refs.h          | 4 +++-
>  3 files changed, 7 insertions(+), 2 deletions(-)
> 
> diff --git a/refs-be-files.c b/refs-be-files.c
> index 37e244a..eaa74b6 100644
> --- a/refs-be-files.c
> +++ b/refs-be-files.c
> @@ -3737,6 +3737,7 @@ int reflog_expire(const char *refname, const unsigned char *sha1,
>  struct ref_be refs_be_files = {
>  	NULL,
>  	"files",
> +	NULL,
>  	files_transaction_begin,
>  	files_transaction_update,
>  	files_transaction_create,
> diff --git a/refs.c b/refs.c
> index 769574d..9ce10b7 100644
> --- a/refs.c
> +++ b/refs.c
> @@ -19,13 +19,15 @@ struct ref_be *refs_backends = &refs_be_files;
>  /*
>   * This function is used to switch to an alternate backend.
>   */
> -int set_refs_backend(const char *name)
> +int set_refs_backend(const char *name, void *init_data)
>  {
>  	struct ref_be *be;
>  
>  	for (be = refs_backends; be; be = be->next)
>  		if (!strcmp(be->name, name)) {
>  			the_refs_backend = be;
> +			if (be->init_backend)
> +				be->init_backend(init_data);

I don't like that this virtual function, alone among all of them introduced so far, is allowed to be NULL. That seems non-obvious and something extra that devs have to remember.

I think it would be better for the files backend to define a do-nothing function that can be stuck in this slot.

If you are opposed to that for some reason, then please at least add a comment where this function pointer is added to `struct ref_be`, warning that it can be NULL.

Show 32 quoted lines
>  			return 0;
>  		}
>  	return 1;
> diff --git a/refs.h b/refs.h
> index 0b407b2..0dc626e 100644
> --- a/refs.h
> +++ b/refs.h
> @@ -586,6 +586,7 @@ extern int reflog_expire(const char *refname, const unsigned char *sha1,
>  			 void *policy_cb_data);
>  
>  /* refs backends */
> +typedef void (*ref_backend_init_fn)(void *data);
>  typedef struct ref_transaction *(*ref_transaction_begin_fn)(struct strbuf *err);
>  typedef int (*ref_transaction_update_fn)(struct ref_transaction *transaction,
>  		const char *refname, const unsigned char *new_sha1,
> @@ -641,6 +642,7 @@ typedef int (*for_each_reftype_fullpath_fn)(each_ref_fn fn, char *type,
>  struct ref_be {
>  	struct ref_be *next;
>  	const char *name;
> +	ref_backend_init_fn init_backend;
>  	ref_transaction_begin_fn transaction_begin;
>  	ref_transaction_update_fn transaction_update;
>  	ref_transaction_create_fn transaction_create;
> @@ -669,6 +671,6 @@ struct ref_be {
>  
>  
>  extern struct ref_be refs_be_files;
> -int set_refs_backend(const char *name);
> +int set_refs_backend(const char *name, void *init_data);
>  
>  #endif /* REFS_H */
> 
Michael
-- 
Michael Haggerty
mhagger@alum.mit.edu
Previous: David TurnerNext: David Turner
Message 44 of 90 in “lmdb ref backend”
  1. 00/43 lmdb ref backendDavid Turner, Sep 28, 2015
  2. 01/43 refs.c: create a public version of verify_refname_availableDavid Turner, Sep 28, 2015
  3. Torsten BögershausenOct 3, 2015
  4. David TurnerOct 3, 2015
  5. Torsten BögershausenOct 3, 2015
  6. Torsten BögershausenOct 4, 2015
  7. Michael HaggertyOct 5, 2015
  8. David TurnerOct 5, 2015
  9. 02/43 refs: make repack_without_refs and is_branch publicDavid Turner, Sep 28, 2015
  10. Michael HaggertyOct 5, 2015
  11. David TurnerOct 5, 2015
  12. 03/43 refs-be-files.c: rename refs to refs-be-filesDavid Turner, Sep 28, 2015
  13. 04/43 refs.c: add a new refs.c file to hold all common refs codeDavid Turner, Sep 28, 2015
  14. 05/43 refs.c: move update_ref to refs.cDavid Turner, Sep 28, 2015
  15. 06/43 refs.c: move delete_ref and delete_refs to the common codeDavid Turner, Sep 28, 2015
  16. 07/43 refs.c: move read_ref_at to the common refs fileDavid Turner, Sep 28, 2015
  17. 08/43 refs.c: move the hidden refs functions to the common codeDavid Turner, Sep 28, 2015
  18. 09/43 refs.c: move dwim and friend functions to the common refs codeDavid Turner, Sep 28, 2015
  19. 10/43 refs.c: move warn_if_dangling_symref* to the common codeDavid Turner, Sep 28, 2015
  20. 11/43 refs.c: move read_ref, read_ref_full and ref_exists to the common codeDavid Turner, Sep 28, 2015
  21. 12/43 refs.c: move resolve_refdup to commonDavid Turner, Sep 28, 2015
  22. 13/43 refs.c: move check_refname_format to the common codeDavid Turner, Sep 28, 2015
  23. 14/43 refs.c: move is_branch to the common codeDavid Turner, Sep 28, 2015
  24. 15/43 refs.c: move prettify_refname to the common codeDavid Turner, Sep 28, 2015
  25. 16/43 refs.c: move ref iterators to the common codeDavid Turner, Sep 28, 2015
  26. 17/43 refs.c: move head_ref_namespaced to the common codeDavid Turner, Sep 28, 2015
  27. 18/43 refs-be-files.c: add a backend method structure with transaction functionsDavid Turner, Sep 28, 2015
  28. Michael HaggertyOct 5, 2015
  29. Junio C HamanoOct 5, 2015
  30. David TurnerOct 6, 2015
  31. 19/43 refs-be-files.c: add methods for misc ref operationsDavid Turner, Sep 28, 2015
  32. 20/43 refs-be-files.c: add methods for the ref iteratorsDavid Turner, Sep 28, 2015
  33. 21/43 refs-be-files.c: add method for for_each_reftype_...David Turner, Sep 28, 2015
  34. 22/43 refs-be-files.c: add do_for_each_per_worktree_refDavid Turner, Sep 28, 2015
  35. Michael HaggertyOct 5, 2015
  36. David TurnerOct 5, 2015
  37. 23/43 refs.c: move refname_is_safe to the common codeDavid Turner, Sep 28, 2015
  38. 24/43 refs.h: document make refname_is_safe and add it to headerDavid Turner, Sep 28, 2015
  39. 25/43 refs.c: move copy_msg to the common codeDavid Turner, Sep 28, 2015
  40. 26/43 refs.c: move peel_object to the common codeDavid Turner, Sep 28, 2015
  41. 27/43 refs.c: move should_autocreate_reflog to common codeDavid Turner, Sep 28, 2015
  42. Junio C HamanoOct 2, 2015
  43. 28/43 refs.c: add ref backend init functionDavid Turner, Sep 28, 2015
  44. Michael HaggertyOct 5, 2015
  45. David TurnerOct 5, 2015
  46. 29/43 refs.c: add methods for reflogDavid Turner, Sep 28, 2015
  47. 30/43 refs-be-files.c: add method to expire reflogsDavid Turner, Sep 28, 2015
  48. Michael HaggertyOct 5, 2015
  49. 31/43 refs.c: add method for initial ref transaction commitDavid Turner, Sep 28, 2015
  50. 32/43 initdb: move safe_create_dir into common codeDavid Turner, Sep 28, 2015
  51. 33/43 refs.c: add method for initializing refs dbDavid Turner, Sep 28, 2015
  52. 34/43 refs.c: make struct ref_transaction genericDavid Turner, Sep 28, 2015
  53. Michael BlumeOct 6, 2015
  54. David TurnerOct 6, 2015
  55. 35/43 refs-be-files.c: add method to rename refsDavid Turner, Sep 28, 2015
  56. 36/43 run-command: track total number of commands runDavid Turner, Sep 28, 2015
  57. 37/43 refs: move some defines from refs-be-files.c to refs.hDavid Turner, Sep 28, 2015
  58. Michael HaggertyOct 5, 2015
  59. 38/43 refs: make some files backend functions publicDavid Turner, Sep 28, 2015
  60. Michael HaggertyOct 5, 2015
  61. David TurnerOct 6, 2015
  62. David TurnerOct 7, 2015
  63. Michael HaggertyOct 7, 2015
  64. Junio C HamanoOct 7, 2015
  65. David TurnerOct 7, 2015
  66. Michael HaggertyOct 7, 2015
  67. 39/43 refs: break out a ref conflict checkDavid Turner, Sep 28, 2015
  68. Michael HaggertyOct 5, 2015
  69. David TurnerOct 6, 2015
  70. 40/43 refs: allow ref backend to be set for cloneDavid Turner, Sep 28, 2015
  71. Michael HaggertyOct 5, 2015
  72. David TurnerOct 6, 2015
  73. Jeff KingOct 6, 2015
  74. David TurnerOct 6, 2015
  75. Carlos Martín NietoOct 12, 2015
  76. Michael HaggertyOct 5, 2015
  77. David TurnerOct 6, 2015
  78. 41/43 refs: add register_refs_backendDavid Turner, Sep 28, 2015
  79. 42/43 refs: add LMDB refs backendDavid Turner, Sep 28, 2015
  80. Junio C HamanoOct 2, 2015
  81. Michael HaggertyOct 5, 2015
  82. David TurnerOct 7, 2015
  83. Michael HaggertyOct 7, 2015
  84. Junio C HamanoOct 7, 2015
  85. David TurnerOct 7, 2015
  86. Michael HaggertyOct 7, 2015
  87. 43/43 refs: tests for db backendDavid Turner, Sep 28, 2015
  88. Dennis KaarsemakerOct 3, 2015
  89. Junio C HamanoOct 5, 2015
  90. David TurnerOct 6, 2015

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