From e8a32e766fe3f5e40fb8918a4d825e6d0b9aa272 Mon Sep 17 00:00:00 2001 From: shejialuo Date: Mon, 6 Oct 2025 14:32:31 +0800 Subject: [PATCH] string-list: replace negative index encoding with "exact_match" parameter The "string_list_find_insert_index()" function is used to determine the correct insertion index for a new string within the string list. The function also doubles up to convey if the string is already existing in the list, this is done by returning a negative index "-1 -index". Users are expected to decode this information. This approach has several limitations: 1. It requires the callers to look into the detail of the function to understand how to decode the negative index encoding. 2. Using int for indices can cause overflow issues when dealing with large string lists. To address these limitations, change the function to return size_t for the index value and use a separate bool parameter to indicate whether the index refers to an existing entry or an insertion point. In some cases, the callers of "string_list_find_insert_index" only need the index position and don't care whether an exact match is found. However, "get_entry_index" currently requires a non-NULL "exact_match" parameter, forcing these callers to declare unnecessary variables. Let's allow callers to pass NULL for the "exact_match" parameter when they don't need this information, reducing unnecessary variable declarations in calling code. Signed-off-by: shejialuo Signed-off-by: Junio C Hamano --- add-interactive.c | 7 ++++--- mailmap.c | 7 +++---- refs.c | 2 +- string-list.c | 14 ++++++-------- string-list.h | 2 +- 5 files changed, 15 insertions(+), 17 deletions(-) diff --git a/add-interactive.c b/add-interactive.c index 3e692b47ec..7c0fd3d218 100644 --- a/add-interactive.c +++ b/add-interactive.c @@ -221,7 +221,8 @@ static void find_unique_prefixes(struct prefix_item_list *list) static ssize_t find_unique(const char *string, struct prefix_item_list *list) { - int index = string_list_find_insert_index(&list->sorted, string, 1); + bool exact_match; + int index = string_list_find_insert_index(&list->sorted, string, &exact_match); struct string_list_item *item; if (list->items.nr != list->sorted.nr) @@ -229,8 +230,8 @@ static ssize_t find_unique(const char *string, struct prefix_item_list *list) " vs %"PRIuMAX")", (uintmax_t)list->items.nr, (uintmax_t)list->sorted.nr); - if (index < 0) - item = list->sorted.items[-1 - index].util; + if (exact_match) + item = list->sorted.items[index].util; else if (index > 0 && starts_with(list->sorted.items[index - 1].string, string)) return -1; diff --git a/mailmap.c b/mailmap.c index 56c72102d9..58a4484963 100644 --- a/mailmap.c +++ b/mailmap.c @@ -243,10 +243,9 @@ void clear_mailmap(struct string_list *map) static struct string_list_item *lookup_prefix(struct string_list *map, const char *string, size_t len) { - int i = string_list_find_insert_index(map, string, 1); - if (i < 0) { - /* exact match */ - i = -1 - i; + bool exact_match; + int i = string_list_find_insert_index(map, string, &exact_match); + if (exact_match) { if (!string[len]) return &map->items[i]; /* diff --git a/refs.c b/refs.c index 4ff55cf24f..f1ff5bf846 100644 --- a/refs.c +++ b/refs.c @@ -1699,7 +1699,7 @@ const char *find_descendant_ref(const char *dirname, * with dirname (remember, dirname includes the trailing * slash) and is not in skip, then we have a conflict. */ - for (pos = string_list_find_insert_index(extras, dirname, 0); + for (pos = string_list_find_insert_index(extras, dirname, NULL); pos < extras->nr; pos++) { const char *extra_refname = extras->items[pos].string; diff --git a/string-list.c b/string-list.c index d8da3dd414..c589ab5a2c 100644 --- a/string-list.c +++ b/string-list.c @@ -29,12 +29,14 @@ static size_t get_entry_index(const struct string_list *list, const char *string else if (compare > 0) left = middle + 1; else { - *exact_match = true; + if (exact_match) + *exact_match = true; return middle; } } - *exact_match = false; + if (exact_match) + *exact_match = false; return right; } @@ -90,13 +92,9 @@ bool 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, - int negative_existing_index) + bool *exact_match) { - bool exact_match; - int index = get_entry_index(list, string, &exact_match); - if (exact_match) - index = -1 - (negative_existing_index ? index : 0); - return index; + return get_entry_index(list, string, exact_match); } struct string_list_item *string_list_lookup(struct string_list *list, const char *string) diff --git a/string-list.h b/string-list.h index bc7f38022e..8830ce671d 100644 --- a/string-list.h +++ b/string-list.h @@ -174,7 +174,7 @@ void string_list_remove_empty_items(struct string_list *list, int free_util); /** Determine if the string_list has a given string or not. */ bool 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, - int negative_existing_index); + bool *exact_match); /** * Insert a new element to the string_list. The returned pointer can -- 2.47.3