tor-browser

commit 1ad1b18a5248e58d3b99163587656b2d16fe58af
parent 8a28ab14664107096b1a47f3d1e33f00822b8d75
Author: serge-sans-paille <sguelton@mozilla.com>
Date:   Thu,  9 Oct 2025 11:47:34 +0000

Bug 1993179 - Simplify mozilla::detail::EmptyChecker implementation r=emilio

Differential Revision: https://phabricator.services.mozilla.com/D267924

Diffstat:
M
mfbt/MruCache.h
 | 
19
++++++++-----------
M
xpcom/tests/gtest/TestMruCache.cpp
 | 
30
------------------------------

2 files changed, 8 insertions(+), 41 deletions(-)
diff --git a/mfbt/MruCache.h b/mfbt/MruCache.h
@@ -22,15 +22,14 @@ namespace detail {
 //
 // `IsNotEmpty` will return true if `Value` is not a pointer type or if the
 // pointer value is not null.
-template <typename Value, bool IsPtr = std::is_pointer<Value>::value>
-struct EmptyChecker {
-  static bool IsNotEmpty(const Value&) { return true; }
-};
-// Template specialization for the `IsPtr == true` case.
 template <typename Value>
-struct EmptyChecker<Value, true> {
-  static bool IsNotEmpty(const Value& aVal) { return aVal != nullptr; }
-};
+constexpr bool IsNotEmpty(const Value& aVal) {
+  if constexpr (!std::is_pointer_v<Value>) {
+    return true;
+  } else {
+    return aVal != nullptr;
+  }
+}
 
 }  // namespace detail
 
@@ -145,10 +144,8 @@ class MruCache {
   // present, update the entry to a new value, or remove the entry if one was
   // matched.
   Entry Lookup(const KeyType& aKey) {
-    using EmptyChecker = detail::EmptyChecker<ValueType>;
-
     auto entry = RawEntry(aKey);
-    bool match = EmptyChecker::IsNotEmpty(*entry) && Cache::Match(aKey, *entry);
+    bool match = detail::IsNotEmpty(*entry) && Cache::Match(aKey, *entry);
     return Entry(entry, match);
   }
 
diff --git a/xpcom/tests/gtest/TestMruCache.cpp b/xpcom/tests/gtest/TestMruCache.cpp
@@ -55,36 +55,6 @@ static nsCString MakeStringKey(char aKey) {
   return key;
 }
 
-TEST(MruCache, TestNullChecker)
-{
-  using mozilla::detail::EmptyChecker;
-
-  {
-    int test = 0;
-    EXPECT_TRUE(EmptyChecker<decltype(test)>::IsNotEmpty(test));
-
-    test = 42;
-    EXPECT_TRUE(EmptyChecker<decltype(test)>::IsNotEmpty(test));
-  }
-
-  {
-    const char* test = "abc";
-    EXPECT_TRUE(EmptyChecker<decltype(test)>::IsNotEmpty(test));
-
-    test = nullptr;
-    EXPECT_FALSE(EmptyChecker<decltype(test)>::IsNotEmpty(test));
-  }
-
-  {
-    int foo = 42;
-    int* test = &foo;
-    EXPECT_TRUE(EmptyChecker<decltype(test)>::IsNotEmpty(test));
-
-    test = nullptr;
-    EXPECT_FALSE(EmptyChecker<decltype(test)>::IsNotEmpty(test));
-  }
-}
-
 TEST(MruCache, TestEmptyCache)
 {
   {