Subject: [RFC PATCH 02/14] strvec: introduce `strvec_init_alloc()`

From: Taylor Blau <[email-masked]>
Date: Tue, 24 Feb 2026 19:21:01 -0500

When the caller knows upfront how many elements will be pushed onto a
`strvec`, it is useful to pre-allocate enough space in the array to fit
that many elements (and one additional slot to store NULL, indicating
the end of the list.)

Introduce `strvec_init_alloc()`, which allocates the backing array large
enough to hold `alloc` elements and the termination marker without
further reallocation.

Signed-off-by: Taylor Blau <[email-masked]>
---
 strvec.c | 7 +++++++
 strvec.h | 5 +++++
 2 files changed, 12 insertions(+)

diff --git a/strvec.c b/strvec.c
index f8de79f5579..f7f32a53b56 100644
--- a/strvec.c
+++ b/strvec.c
@@ -10,6 +10,13 @@ void strvec_init(struct strvec *array)
 	memcpy(array, &blank, sizeof(*array));
 }
 
+void strvec_init_alloc(struct strvec *array, size_t alloc)
+{
+	CALLOC_ARRAY(array->v, st_add(alloc, 1));
+	array->nr = 0;
+	array->alloc = alloc + 1;
+}
+
 void strvec_push_nodup(struct strvec *array, char *value)
 {
 	if (array->v == empty_strvec)
diff --git a/strvec.h b/strvec.h
index f74e061e141..34cb1f939f0 100644
--- a/strvec.h
+++ b/strvec.h
@@ -43,6 +43,11 @@ struct strvec {
  */
 void strvec_init(struct strvec *);
 
+/*
+ * Initializes an array large enough to store `alloc` elements.
+ */
+void strvec_init_alloc(struct strvec *, size_t alloc);
+
 /* Push a copy of a string onto the end of the array. */
 const char *strvec_push(struct strvec *, const char *);
 
-- 
2.53.0.185.g29bc4dff628