astutils.cpp: moved memoize() helper to utils.h (danmar#7257)

Author: firewave

lib/astutils.cpp

@@ -2875,21 +2875,6 @@ const Token* findEscapeStatement(const Scope* scope, const Library* library)
     return nullptr;
 }
 
-// Thread-unsafe memoization
-template<class F, class R=decltype(std::declval<F>()())>
-static std::function<R()> memoize(F f)
-{
-    bool init = false;
-    R result{};
-    return [=]() mutable -> R {
-        if (init)
-            return result;
-        result = f();
-        init = true;
-        return result;
-    };
-}
-
 template<class F,
          REQUIRES("F must be a function that returns a Token class",
                   std::is_convertible<decltype(std::declval<F>()()), const Token*> )>
@@ -2954,7 +2939,7 @@ Token* findVariableChanged(Token *start, const Token *end, int indirect, const n
         return nullptr;
     if (depth < 0)
         return start;
-    auto getExprTok = memoize([&] {
+    auto getExprTok = utils::memoize([&] {
         return findExpression(start, exprid);
     });
     for (Token *tok = start; tok != end; tok = tok->next()) {

lib/utils.h

@@ -411,6 +411,21 @@ namespace utils {
         // NOLINTNEXTLINE(bugprone-return-const-ref-from-parameter) - potential false positive
         return t;
     }
+
+    // Thread-unsafe memoization
+    template<class F, class R=decltype(std::declval<F>()())>
+    static inline std::function<R()> memoize(F f)
+    {
+        bool init = false;
+        R result{};
+        return [=]() mutable -> R {
+            if (init)
+                return result;
+            result = f();
+            init = true;
+            return result;
+        };
+    }
 }
 
 #endif

test/testutils.cpp

@@ -43,6 +43,7 @@ class TestUtils : public TestFixture {
         TEST_CASE(replaceEscapeSequences);
         TEST_CASE(splitString);
         TEST_CASE(as_const);
+        TEST_CASE(memoize);
     }
 
     void isValidGlobPattern() const {
@@ -518,6 +519,22 @@ class TestUtils : public TestFixture {
             ASSERT(c.written);
         }
     }
+
+    void memoize() const {
+        int count = 0;
+        auto f = [&count]() {
+            ++count;
+            return count;
+        };
+        const auto callF = utils::memoize([&]() {
+            return f();
+        });
+        ASSERT_EQUALS(0, count);
+        ASSERT_EQUALS(1, callF());
+        ASSERT_EQUALS(1, count);
+        ASSERT_EQUALS(1, callF());
+        ASSERT_EQUALS(1, count);
+    }
 };
 
 REGISTER_TEST(TestUtils)