Allow makeStaticObserver(std::shared_ptr<const T>)

Summary: Observers operate with `std::shared_ptr<const T>` internally so it's natural and convenient to allow `makeStaticObserver(std::shared_ptr<const T>)`. Reviewed By: praihan Differential Revision: D64764178 fbshipit-source-id: 4343dfdbe0af42defbe3b3d386b36b1c9b07dd79
facebook · Oct 24, 2024 · 2498c34 · 2498c34
1 parent 2d0f8ed
commit 2498c34
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Showing 3 changed files with 11 additions and 2 deletions.
diff --git a/folly/observer/Observer-inl.h b/folly/observer/Observer-inl.h
@@ -106,7 +106,7 @@ Observer<T> makeStaticObserver(T value) {
 }
 
 template <typename T>
-Observer<T> makeStaticObserver(std::shared_ptr<T> value) {
+Observer<std::decay_t<T>> makeStaticObserver(std::shared_ptr<T> value) {
   return makeObserver([value_2 = std::move(value)] { return value_2; });
 }
 

diff --git a/folly/observer/Observer.h b/folly/observer/Observer.h
@@ -310,7 +310,7 @@ template <typename T>
 Observer<T> makeStaticObserver(T value);
 
 template <typename T>
-Observer<T> makeStaticObserver(std::shared_ptr<T> value);
+Observer<std::decay_t<T>> makeStaticObserver(std::shared_ptr<T> value);
 
 template <typename T>
 class AtomicObserver {

diff --git a/folly/observer/test/ObserverTest.cpp b/folly/observer/test/ObserverTest.cpp
@@ -627,8 +627,17 @@ TEST(Observer, MakeStaticObserver) {
       makeStaticObserver<std::shared_ptr<int>>(std::make_shared<int>(5));
   EXPECT_EQ(***explicitSharedPtrObserver, 5);
 
+  auto explicitSharedPtrToConstObserver =
+      makeStaticObserver<std::shared_ptr<const int>>(
+          std::make_shared<const int>(5));
+  EXPECT_EQ(***explicitSharedPtrToConstObserver, 5);
+
   auto implicitSharedPtrObserver = makeStaticObserver(std::make_shared<int>(5));
   EXPECT_EQ(**implicitSharedPtrObserver, 5);
+
+  auto implicitSharedPtrToConstObserver =
+      makeStaticObserver(std::make_shared<const int>(5));
+  EXPECT_EQ(**implicitSharedPtrToConstObserver, 5);
 }
 
 TEST(Observer, AtomicObserver) {