This function allows entries that don't match a specified criterion to
be discarded from a string_list while preserving the order of the
remaining entries.
Signed-off-by: Michael Haggerty <mhagger@xxxxxxxxxxxx>
---
Documentation/technical/api-string-list.txt | 11 +++++++
string-list.c | 17 ++++++++++
string-list.h | 9 ++++++
t/t0063-string-list.sh | 11 +++++++
test-string-list.c | 48 +++++++++++++++++++++++++++++
5 files changed, 96 insertions(+)
diff --git a/Documentation/technical/api-string-list.txt b/Documentation/technical/api-string-list.txt
index 670217c..ea65818 100644
--- a/Documentation/technical/api-string-list.txt
+++ b/Documentation/technical/api-string-list.txt
@@ -33,6 +33,9 @@ member (you need this if you add things later) and you should set the
. Can remove individual items of an unsorted list using
`unsorted_string_list_delete_item`.
+. Can remove items not matching a criterion from a sorted or unsorted
+ list using `filter_string_list`.
+
. Finally it should free the list using `string_list_clear`.
Example:
@@ -61,6 +64,14 @@ Functions
* General ones (works with sorted and unsorted lists as well)
+`filter_string_list`::
+
+ Apply a function to each item in a list, retaining only the
+ items for which the function returns true. If free_util is
+ true, call free() on the util members of any items that have
+ to be deleted. Preserve the order of the items that are
+ retained.
+
`print_string_list`::
Dump a string_list to stdout, useful mainly for debugging purposes. It
diff --git a/string-list.c b/string-list.c
index f9051ec..e0806fb 100644
--- a/string-list.c
+++ b/string-list.c
@@ -102,6 +102,23 @@ int for_each_string_list(struct string_list *list,
return ret;
}
+void filter_string_list(struct string_list *list, int free_util,
+ string_list_each_func_t want, void *cb_data)
+{
+ int src, dst = 0;
+ for (src = 0; src < list->nr; src++) {
+ if (want(&list->items[src], cb_data)) {
+ list->items[dst++] = list->items[src];
+ } else {
+ if (list->strdup_strings)
+ free(list->items[src].string);
+ if (free_util)
+ free(list->items[src].util);
+ }
+ }
+ list->nr = dst;
+}
+
void string_list_clear(struct string_list *list, int free_util)
{
if (list->items) {
diff --git a/string-list.h b/string-list.h
index dc5fbc8..7d18e62 100644
--- a/string-list.h
+++ b/string-list.h
@@ -29,6 +29,15 @@ int for_each_string_list(struct string_list *list,
#define for_each_string_list_item(item,list) \
for (item = (list)->items; item < (list)->items + (list)->nr; ++item)
+/*
+ * Apply want to each item in list, retaining only the ones for which
+ * the function returns true. If free_util is true, call free() on
+ * the util members of any items that have to be deleted. Preserve
+ * the order of the items that are retained.
+ */
+void filter_string_list(struct string_list *list, int free_util,
+ string_list_each_func_t want, void *cb_data);
+
/* Use these functions only on sorted lists: */
int string_list_has_string(const struct string_list *list, const char *string);
diff --git a/t/t0063-string-list.sh b/t/t0063-string-list.sh
index fb85430..a5f05cd 100755
--- a/t/t0063-string-list.sh
+++ b/t/t0063-string-list.sh
@@ -60,4 +60,15 @@ test_split ":" ":" "-1" <<EOF
[1]: ""
EOF
+test_expect_success "test filter_string_list" '
+ test "x-" = "x$(test-string-list filter - y)" &&
+ test "x-" = "x$(test-string-list filter no y)" &&
+ test yes = "$(test-string-list filter yes y)" &&
+ test yes = "$(test-string-list filter no:yes y)" &&
+ test yes = "$(test-string-list filter yes:no y)" &&
+ test y1:y2 = "$(test-string-list filter y1:y2 y)" &&
+ test y2:y1 = "$(test-string-list filter y2:y1 y)" &&
+ test "x-" = "x$(test-string-list filter x1:x2 y)"
+'
+
test_done
diff --git a/test-string-list.c b/test-string-list.c
index cdc3cf3..702276c 100644
--- a/test-string-list.c
+++ b/test-string-list.c
@@ -1,6 +1,20 @@
#include "cache.h"
#include "string-list.h"
+/*
+ * Parse an argument into a string list. arg should either be a
+ * ':'-separated list of strings, or "-" to indicate an empty string
+ * list (as opposed to "", which indicates a string list containing a
+ * single empty string). list->strdup_strings must be set.
+ */
+void parse_string_list(struct string_list *list, const char *arg)
+{
+ if (!strcmp(arg, "-"))
+ return;
+
+ (void)string_list_split(list, arg, ':', -1);
+}
+
void write_list(const struct string_list *list)
{
int i;
@@ -8,6 +22,25 @@ void write_list(const struct string_list *list)
printf("[%d]: \"%s\"\n", i, list->items[i].string);
}
+void write_list_compact(const struct string_list *list)
+{
+ int i;
+ if (!list->nr)
+ printf("-\n");
+ else {
+ printf("%s", list->items[0].string);
+ for (i = 1; i < list->nr; i++)
+ printf(":%s", list->items[i].string);
+ printf("\n");
+ }
+}
+
+int prefix_cb(struct string_list_item *item, void *cb_data)
+{
+ const char *prefix = (const char *)cb_data;
+ return !prefixcmp(item->string, prefix);
+}
+
int main(int argc, char **argv)
{
if (argc == 5 && !strcmp(argv[1], "split")) {
@@ -39,6 +72,21 @@ int main(int argc, char **argv)
return 0;
}
+ if (argc == 4 && !strcmp(argv[1], "filter")) {
+ /*
+ * Retain only the items that have the specified prefix.
+ * Arguments: list|- prefix
+ */
+ struct string_list list = STRING_LIST_INIT_DUP;
+ const char *prefix = argv[3];
+
+ parse_string_list(&list, argv[2]);
+ filter_string_list(&list, 0, prefix_cb, (void *)prefix);
+ write_list_compact(&list);
+ string_list_clear(&list, 0);
+ return 0;
+ }
+
fprintf(stderr, "%s: unknown function name: %s\n", argv[0],
argv[1] ? argv[1] : "(there was none)");
return 1;
--
1.7.11.3
--
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