commit 5b17d59: [Minor] Add std::hash specialisation + tests

[Vsevolod Stakhov]

Author: Vsevolod Stakhov
Date: 2021-07-23 15:09:19 +0100
URL: https://github.com/rspamd/rspamd/commit/5b17d5900cefe0f220554ff7a5235de308f2abbd (HEAD -> master)

[Minor] Add std::hash specialisation + tests

---
 src/libutil/cxx/local_shared_ptr.hxx | 14 +++++++---
 test/rspamd_cxx_local_ptr.hxx        | 50 ++++++++++++++++++++++++++++--------
 2 files changed, 50 insertions(+), 14 deletions(-)

diff --git a/src/libutil/cxx/local_shared_ptr.hxx b/src/libutil/cxx/local_shared_ptr.hxx
index 81cbe6d08..cf0875813 100644
--- a/src/libutil/cxx/local_shared_ptr.hxx
+++ b/src/libutil/cxx/local_shared_ptr.hxx
@@ -340,14 +340,20 @@ private:
 namespace std {
 template <class T>
 struct hash<rspamd::local_shared_ptr<T>> {
-	inline auto operator()(const rspamd::local_shared_ptr<T> &p) const noexcept -> auto {
-		return hash<T *>()(p.get());
+	inline auto operator()(const rspamd::local_shared_ptr<T> &p) const -> auto {
+		if (!p) {
+			throw std::logic_error("no hash for dangling pointer");
+		}
+		return hash<T>()(*p.get());
 	}
 };
 template <class T>
 struct hash<rspamd::local_weak_ptr<T>> {
-	inline auto operator()(const rspamd::local_weak_ptr<T> &p) const noexcept -> auto {
-		return hash<T *>()(p.get());
+	inline auto operator()(const rspamd::local_weak_ptr<T> &p) const -> auto {
+		if (!p) {
+			throw std::logic_error("no hash for dangling pointer");
+		}
+		return hash<T>()(*p.get());
 	}
 };
 
diff --git a/test/rspamd_cxx_local_ptr.hxx b/test/rspamd_cxx_local_ptr.hxx
index 5b0554292..a9db65dc3 100644
--- a/test/rspamd_cxx_local_ptr.hxx
+++ b/test/rspamd_cxx_local_ptr.hxx
@@ -22,7 +22,36 @@
 
 #include "libutil/cxx/local_shared_ptr.hxx"
 
+namespace test_internal {
+struct deleter_test {
+	bool *pv;
+
+	deleter_test(bool &v)
+	{
+		v = false;
+		pv = &v;
+	}
+
+	~deleter_test()
+	{
+		*pv = true;
+	}
+};
+}
+
+namespace std {
+template<>
+struct std::hash<test_internal::deleter_test> {
+	inline auto operator()(const test_internal::deleter_test &) const noexcept -> auto
+	{
+		return 42;
+	}
+};
+}
+
 TEST_SUITE("local_ptr") {
+using namespace test_internal;
+
 TEST_CASE("shared_ptr from nullptr")
 {
 	rspamd::local_shared_ptr<int const> pi(static_cast<int *>(nullptr));
@@ -118,16 +147,6 @@ TEST_CASE("shared_ptr move")
 	CHECK(pi.use_count() != pi2.use_count());
 }
 
-struct deleter_test {
-	bool *pv;
-	deleter_test(bool &v) {
-		v = false;
-		pv = &v;
-	}
-	~deleter_test() {
-		*pv = true;
-	}
-};
 TEST_CASE("shared_ptr dtor") {
 	bool t;
 
@@ -305,6 +324,17 @@ TEST_CASE("std::swap") {
 	CHECK(t == true);
 }
 
+TEST_CASE("std::hash") {
+	bool v;
+	deleter_test dt(v);
+	CHECK(std::hash<deleter_test>()(dt) == 42);
+	auto pi = rspamd::local_make_shared<deleter_test>(v);
+	rspamd::local_shared_ptr<deleter_test> pi1;
+	CHECK(std::hash<decltype(pi)>()(pi) == 42);
+	// No hash for nullptr, different from std::smart_pointers!
+	CHECK_THROWS(std::hash<decltype(pi)>()(pi1));
+}
+
 }
 
 #endif //RSPAMD_RSPAMD_CXX_LOCAL_PTR_HXX