From 847ae7dd7c947eef2c00de972eabe8bc32f56f83 Mon Sep 17 00:00:00 2001
From: Max Kellermann <max.kellermann@gmail.com>
Date: Mon, 11 Sep 2023 20:57:51 +0200
Subject: [PATCH] util/IntrusiveHashSet: add insert_check_if()
---
src/util/IntrusiveHashSet.hxx | 19 +++++++++++++++++++
1 file changed, 19 insertions(+)
diff --git a/src/util/IntrusiveHashSet.hxx b/src/util/IntrusiveHashSet.hxx
index 07fe3ccaf..69603ab1c 100644
--- a/src/util/IntrusiveHashSet.hxx
+++ b/src/util/IntrusiveHashSet.hxx
@@ -276,6 +276,25 @@ public:
return {bucket.end(), true};
}
+ /**
+ * Like insert_check(), but existing items are only considered
+ * conflicting if they match the given predicate.
+ */
+ [[nodiscard]] [[gnu::pure]]
+ constexpr std::pair<bucket_iterator, bool> insert_check_if(const auto &key,
+ std::predicate<const_reference> auto pred) noexcept {
+ auto &bucket = GetBucket(key);
+ for (auto &i : bucket)
+ if (ops.equal(key, ops.get_key(i)) && pred(i))
+ return {bucket.iterator_to(i), false};
+
+ /* bucket.end() is a pointer to the bucket's list
+ head, a stable value that is guaranteed to be still
+ valid when insert_commit() gets called
+ eventually */
+ return {bucket.end(), true};
+ }
+
/**
* Finish the insertion if insert_check() has returned true.
*