From d83a764899d308f3028756081581d942d9badfce Mon Sep 17 00:00:00 2001
From: Carlos Zamora <cazamor@microsoft.com>
Date: Thu, 10 Jun 2021 13:37:44 -0700
Subject: [PATCH] cache the special hash value

---
 src/cascadia/TerminalSettingsModel/ActionArgs.h  | 13 +++++++++++++
 src/cascadia/TerminalSettingsModel/ActionMap.cpp |  8 ++++----
 2 files changed, 17 insertions(+), 4 deletions(-)

diff --git a/src/cascadia/TerminalSettingsModel/ActionArgs.h b/src/cascadia/TerminalSettingsModel/ActionArgs.h
index 6cf7d8cb53a..40d178b7df1 100644
--- a/src/cascadia/TerminalSettingsModel/ActionArgs.h
+++ b/src/cascadia/TerminalSettingsModel/ActionArgs.h
@@ -68,6 +68,19 @@ constexpr size_t Microsoft::Terminal::Settings::Model::HashUtils::HashProperty(c
     return gsl::narrow_cast<size_t>(args.Hash());
 }
 
+// Retrieves the hash value for an empty-constructed object.
+template<typename T>
+static size_t EmptyHash()
+{
+    // cache the value of the empty hash
+    static size_t cachedHash{ 0 };
+    if (!cachedHash)
+    {
+        cachedHash = { winrt::make_self<T>()->Hash() };
+    }
+    return cachedHash;
+}
+
 namespace winrt::Microsoft::Terminal::Settings::Model::implementation
 {
     using namespace ::Microsoft::Terminal::Settings::Model;
diff --git a/src/cascadia/TerminalSettingsModel/ActionMap.cpp b/src/cascadia/TerminalSettingsModel/ActionMap.cpp
index 15dcf46e1ae..5decbab3d76 100644
--- a/src/cascadia/TerminalSettingsModel/ActionMap.cpp
+++ b/src/cascadia/TerminalSettingsModel/ActionMap.cpp
@@ -28,10 +28,10 @@ namespace winrt::Microsoft::Terminal::Settings::Model::implementation
             // Check if the ShortcutAction supports args.
             switch (actionAndArgs.Action())
             {
-#define ON_ALL_ACTIONS_WITH_ARGS(action)                                    \
-    case ShortcutAction::action:                                            \
-        /* If it does, hash the default values for the args.*/              \
-        hashedArgs = gsl::narrow_cast<size_t>(make<action##Args>().Hash()); \
+#define ON_ALL_ACTIONS_WITH_ARGS(action)                        \
+    case ShortcutAction::action:                                \
+        /* If it does, hash the default values for the args.*/  \
+        hashedArgs = EmptyHash<implementation::action##Args>(); \
         break;
                 ALL_SHORTCUT_ACTIONS_WITH_ARGS
 #undef ON_ALL_ACTIONS_WITH_ARGS