add GetOrNull method to threadsafe cache

2c3ce3e36d35b563fe21b581380310ac84007f57

2 files changed, 31 insertions, 0 deletions

diff --git a/library/cpp/cache/thread_safe_cache.h b/library/cpp/cache/thread_safe_cache.h
index 08c899ad3d..e77d1a45fd 100644
--- a/library/cpp/cache/thread_safe_cache.h
+++ b/library/cpp/cache/thread_safe_cache.h
@@ -49,6 +49,16 @@ namespace NPrivate {
             Cache.Update(key, value);
         }
 
+        const TPtr GetOrNull(TArgs... args) {
+            Key key = Callbacks.GetKey(args...);
+            TReadGuard r(Mutex);
+            auto iter = Cache.Find(key);
+            if (iter == Cache.End()) {
+                return nullptr;
+            }
+            return iter.Value();
+        }
+
         const TPtr Get(TArgs... args) const {
             return GetValue<true>(args...);
         }
diff --git a/library/cpp/cache/ut/cache_ut.cpp b/library/cpp/cache/ut/cache_ut.cpp
index 8546bc166c..16f29b29d1 100644
--- a/library/cpp/cache/ut/cache_ut.cpp
+++ b/library/cpp/cache/ut/cache_ut.cpp
@@ -513,6 +513,27 @@ Y_UNIT_TEST_SUITE(TThreadSafeCacheTest) {
         UNIT_ASSERT(callbacks.Creations == 0);
         UNIT_ASSERT(*item == "hjk");
     }
+
+    Y_UNIT_TEST(GetOrNullTest) {
+        TCallbacks callbacks;
+        TCache cache(callbacks, 10);
+        i32 expectedCreations = 0;
+
+        auto item = cache.GetOrNull(0);
+        UNIT_ASSERT(item == nullptr);
+        UNIT_ASSERT(callbacks.Creations == expectedCreations);
+        UNIT_ASSERT(cache.TotalSize() == 0);
+
+        item = cache.Get(0);
+        UNIT_ASSERT(*item == "abcd");
+        UNIT_ASSERT(callbacks.Creations == ++expectedCreations);
+        UNIT_ASSERT(cache.TotalSize() == 1);
+
+        item = cache.GetOrNull(0);
+        UNIT_ASSERT(*item == "abcd");
+        UNIT_ASSERT(callbacks.Creations == expectedCreations);
+        UNIT_ASSERT(cache.TotalSize() == 1);
+    }
 }
 
 Y_UNIT_TEST_SUITE(TThreadSafeCacheUnsafeTest) {