From bca9beb0d2da988aec25fe776ea1bfda84897d9a Mon Sep 17 00:00:00 2001
From: jian he <jian.universality@gmail.com>
Date: Thu, 6 Mar 2025 09:58:56 +0800
Subject: [PATCH v4 2/3] add function DomainHaveVolatileConstraints

bool DomainHaveVolatileConstraints(Oid type_id, bool *have_volatile);

Returns true if the Domain has any constraints.
If you want check this domain have any volatile check constraints,
make sure have_volatile is not NULL.

discussion: https://postgr.es/m/CACJufxE_+iZBR1i49k_AHigppPwLTJi6km8NOsC7FWvKdEmmXg@mail.gmail.com
---
 src/backend/utils/cache/typcache.c | 37 ++++++++++++++++++++++++++++++
 src/include/utils/typcache.h       |  1 +
 2 files changed, 38 insertions(+)

diff --git a/src/backend/utils/cache/typcache.c b/src/backend/utils/cache/typcache.c
index 5a3b3788d02..617d0ec27cf 100644
--- a/src/backend/utils/cache/typcache.c
+++ b/src/backend/utils/cache/typcache.c
@@ -1498,6 +1498,43 @@ DomainHasConstraints(Oid type_id)
 }
 
 
+/*
+ * Returns true if the Domain has any constraints.
+ * To check for the presence of volatile constraints, ensure
+ * have_volatile is not NULL. If a volatile constraint exists,
+ * have_volatile will be true.
+ */
+bool
+DomainHaveVolatileConstraints(Oid type_id, bool *have_volatile)
+{
+	TypeCacheEntry *typentry;
+
+	/*
+	 * Note: a side effect is to cause the typcache's domain data to become
+	 * valid.  This is fine since we'll likely need it soon if there is any.
+	 */
+	typentry = lookup_type_cache(type_id, TYPECACHE_DOMAIN_CONSTR_INFO);
+
+	if (typentry->domainData != NULL)
+	{
+		ListCell   *lc;
+
+		foreach(lc, typentry->domainData->constraints)
+		{
+			DomainConstraintState *r = (DomainConstraintState *) lfirst(lc);
+
+			if (r->constrainttype == DOM_CONSTRAINT_CHECK &&
+				contain_volatile_functions((Node *) r->check_expr))
+			{
+				*have_volatile = true;
+				break;
+			}
+		}
+		return true;
+	}
+	return false;
+}
+
 /*
  * array_element_has_equality and friends are helper routines to check
  * whether we should believe that array_eq and related functions will work
diff --git a/src/include/utils/typcache.h b/src/include/utils/typcache.h
index 562a581333a..36257c4240c 100644
--- a/src/include/utils/typcache.h
+++ b/src/include/utils/typcache.h
@@ -183,6 +183,7 @@ extern void InitDomainConstraintRef(Oid type_id, DomainConstraintRef *ref,
 extern void UpdateDomainConstraintRef(DomainConstraintRef *ref);
 
 extern bool DomainHasConstraints(Oid type_id);
+extern bool DomainHaveVolatileConstraints(Oid type_id, bool *have_volatile);
 
 extern TupleDesc lookup_rowtype_tupdesc(Oid type_id, int32 typmod);
 
-- 
2.34.1