Re: [PATCH 3/4] Add a new function, string_list_remove_duplicates()

[Junio C Hamano <gitster@pobox.com>]

Michael Haggerty <mhagger@alum.mit.edu> writes:

> Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
> ---
>  Documentation/technical/api-string-list.txt |  4 ++++
>  string-list.c                               | 17 +++++++++++++++++
>  string-list.h                               |  5 +++++
>  3 files changed, 26 insertions(+)
>
> diff --git a/Documentation/technical/api-string-list.txt b/Documentation/technical/api-string-list.txt
> index 15b8072..9206f8f 100644
> --- a/Documentation/technical/api-string-list.txt
> +++ b/Documentation/technical/api-string-list.txt
> @@ -104,6 +104,10 @@ write `string_list_insert(...)->util = ...;`.
>  	Look up a given string in the string_list, returning the containing
>  	string_list_item. If the string is not found, NULL is returned.
>  
> +`string_list_remove_duplicates`::
> +
> +	Remove all but the first entry that has a given string value.

Unlike the previous patch, free_util is not documented?

It is kind of shame that the string list must be sorted for this
function to work, but I guess you do not have a need for a version
that works on both sorted and unsorted (yet).  We can introduce a
variant with "unsorted_" prefix later when it becomes necessary, so
OK.

>  * Functions for unsorted lists only
>  
>  `string_list_append`::
> diff --git a/string-list.c b/string-list.c
> index 72610ce..bfef6cf 100644
> --- a/string-list.c
> +++ b/string-list.c
> @@ -92,6 +92,23 @@ struct string_list_item *string_list_lookup(struct string_list *list, const char
>  	return list->items + i;
>  }
>  
> +void string_list_remove_duplicates(struct string_list *list, int free_util)
> +{
> +	if (list->nr > 1) {
> +		int src, dst;
> +		for (src = dst = 1; src < list->nr; src++) {
> +			if (!strcmp(list->items[dst - 1].string, list->items[src].string)) {
> +				if (list->strdup_strings)
> +					free(list->items[src].string);
> +				if (free_util)
> +					free(list->items[src].util);
> +			} else
> +				list->items[dst++] = list->items[src];
> +		}
> +		list->nr = dst;
> +	}
> +}
> +
>  int for_each_string_list(struct string_list *list,
>  			 string_list_each_func_t fn, void *cb_data)
>  {
> diff --git a/string-list.h b/string-list.h
> index 84996aa..c4dc659 100644
> --- a/string-list.h
> +++ b/string-list.h
> @@ -38,6 +38,7 @@ int for_each_string_list(struct string_list *list,
>  void filter_string_list(struct string_list *list, int free_util,
>  			string_list_each_func_t fn, void *cb_data);
>  
> +
>  /* Use these functions only on sorted lists: */
>  int string_list_has_string(const struct string_list *list, const char *string);
>  int string_list_find_insert_index(const struct string_list *list, const char *string,
> @@ -47,6 +48,10 @@ struct string_list_item *string_list_insert_at_index(struct string_list *list,
>  						     int insert_at, const char *string);
>  struct string_list_item *string_list_lookup(struct string_list *list, const char *string);
>  
> +/* Remove all but the first entry that has a given string value. */
> +void string_list_remove_duplicates(struct string_list *list, int free_util);
> +
> +
>  /* Use these functions only on unsorted lists: */
>  struct string_list_item *string_list_append(struct string_list *list, const char *string);
>  void sort_string_list(struct string_list *list);