From 06cef7bcc2624d9b1e3a19dc3d06ba683d11c5c1 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Marek=20Ol=C5=A1=C3=A1k?= <marek.olsak@amd.com>
Date: Mon, 11 Aug 2025 02:27:34 -0400
Subject: [PATCH] util/set: add _mesa_set_copy, a cloning helper without
 allocation

Reviewed-by: Gert Wollny <gert.wollny@collabora.com>
Acked-by: Pierre-Eric Pelloux-Prayer <pierre-eric.pelloux-prayer@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/36728>
---
 src/util/set.c | 41 ++++++++++++++++++++++++++---------------
 src/util/set.h |  3 +++
 2 files changed, 29 insertions(+), 15 deletions(-)

diff --git a/src/util/set.c b/src/util/set.c
index 5ca78bbdfa9..d6c06235a3c 100644
--- a/src/util/set.c
+++ b/src/util/set.c
@@ -203,6 +203,29 @@ _mesa_set_create_u32_keys(void *mem_ctx)
    return _mesa_set_create(mem_ctx, key_u32_hash, key_u32_equals);
 }
 
+/* Copy the set from src to dst. */
+bool
+_mesa_set_copy(struct set *dst, struct set *src, void *dst_mem_ctx)
+{
+   /* Copy the structure except the initial storage. */
+   memcpy(dst, src, offsetof(struct set, _initial_storage));
+   dst->mem_ctx = dst_mem_ctx;
+
+   if (src->table != src->_initial_storage) {
+      dst->table = ralloc_array(dst_mem_ctx, struct set_entry, dst->size);
+      if (dst->table == NULL)
+         return false;
+
+      memcpy(dst->table, src->table, dst->size * sizeof(struct set_entry));
+   } else {
+      dst->table = dst->_initial_storage;
+      memcpy(dst->table, src->_initial_storage, sizeof(src->_initial_storage));
+   }
+
+   return true;
+}
+
+/* It's preferred to use _mesa_set_copy instead of this to skip ralloc. */
 struct set *
 _mesa_set_clone(struct set *set, void *dst_mem_ctx)
 {
@@ -212,21 +235,9 @@ _mesa_set_clone(struct set *set, void *dst_mem_ctx)
    if (clone == NULL)
       return NULL;
 
-   /* Copy the whole structure except the initial storage. */
-   memcpy(clone, set, offsetof(struct set, _initial_storage));
-   clone->mem_ctx = dst_mem_ctx;
-
-   if (set->table != set->_initial_storage) {
-      clone->table = ralloc_array(dst_mem_ctx, struct set_entry, clone->size);
-      if (clone->table == NULL) {
-         ralloc_free(clone);
-         return NULL;
-      }
-
-      memcpy(clone->table, set->table, clone->size * sizeof(struct set_entry));
-   } else {
-      clone->table = clone->_initial_storage;
-      memcpy(clone->table, set->_initial_storage, sizeof(set->_initial_storage));
+   if (!_mesa_set_copy(clone, set, dst_mem_ctx)) {
+      ralloc_free(clone);
+      return NULL;
    }
 
    return clone;
diff --git a/src/util/set.h b/src/util/set.h
index 1c2eb5759c1..13cbb794d09 100644
--- a/src/util/set.h
+++ b/src/util/set.h
@@ -88,6 +88,9 @@ _mesa_set_create(void *mem_ctx,
 struct set *
 _mesa_set_create_u32_keys(void *mem_ctx);
 
+bool
+_mesa_set_copy(struct set *dst, struct set *src, void *dst_mem_ctx);
+
 struct set *
 _mesa_set_clone(struct set *set, void *dst_mem_ctx);