cppcheck.cpp: added UNUSEDFUNCTION_ONLY hack to only perform the unusedFunction check

Author: firewave

lib/cppcheck.cpp

@@ -1015,6 +1015,10 @@ void CppCheck::checkRawTokens(const Tokenizer &tokenizer)
 
 void CppCheck::checkNormalTokens(const Tokenizer &tokenizer)
 {
+    // TODO: this should actually be the behavior if only "--enable=unusedFunction" is specified - see #10648
+    const char* unusedFunctionOnly = std::getenv("UNUSEDFUNCTION_ONLY");
+    const bool doUnusedFunctionOnly = unusedFunctionOnly && (std::strcmp(unusedFunctionOnly, "1") == 0);
+
     // call all "runChecks" in all registered Check classes
     for (Check *check : Check::instances()) {
         if (Settings::terminated())
@@ -1023,6 +1027,9 @@ void CppCheck::checkNormalTokens(const Tokenizer &tokenizer)
         if (Tokenizer::isMaxTime())
             return;
 
+        if (doUnusedFunctionOnly && dynamic_cast<CheckUnusedFunctions*>(check) == nullptr)
+            continue;
+
         Timer timerRunChecks(check->name() + "::runChecks", mSettings.showtime, &s_timerResults);
         check->runChecks(&tokenizer, &mSettings, this);
     }