Specialize TfHashAppend for std::shared_ptr and std::unique_ptr

pxr/base/tf/hash.h

@@ -34,6 +34,7 @@
 #include <cstring>
 #include <string>
 #include <map>
+#include <memory>
 #include <set>
 #include <typeindex>
 #include <type_traits>
@@ -142,6 +143,22 @@ TfHashAppend(HashState &h, const T* ptr) {
     return h.Append(reinterpret_cast<uintptr_t>(ptr));
 }
 
+// Support for hashing std::shared_ptr. When TfHash support for std::hash is
+// enabled, this explicit specialization will no longer be necessary.
+template <class HashState, class T>
+inline void
+TfHashAppend(HashState &h, const std::shared_ptr<T>& ptr) {
+    h.Append(std::hash<std::shared_ptr<T>>{}(ptr));
+}
+
+// Support for hashing std::unique_ptr. When TfHash support for std::hash is
+// enabled, this explicit specialization will no longer be necessary.
+template <class HashState, class T>
+inline void
+TfHashAppend(HashState &h, const std::unique_ptr<T>& ptr) {
+    h.Append(std::hash<std::unique_ptr<T>>{}(ptr));
+}
+
 // We refuse to hash [const] char *.  You're almost certainly trying to hash the
 // pointed-to string and this will not do that (it will hash the pointer
 // itself).  To hash a c-style null terminated string, you can use

pxr/base/tf/testenv/hash.cpp

@@ -315,6 +315,12 @@ Test_TfHash()
     // Validate support for std::type_index
     printf("hash(type_index): %zu\n", h(std::type_index(typeid(int))));
 
+    // Validate support for std::shared_ptr
+    printf("hash(shared_ptr): %zu\n", h(std::make_shared<int>(5)));
+
+    // Validate support for std::unique_ptr
+    printf("hash(unique_ptr): %zu\n", h(std::make_unique<int>(7)));
+
     TfHasher tfh;
     //BoostHasher bh;