Add ability to StringVerifier to test for non-emptiness

include/openspace/documentation/verifier.h

@@ -156,7 +156,17 @@ struct IntVerifier : public TemplateVerifier<int> {
  * <code>std::string</code>. No implicit conversion is considered in this testing.
  */
 struct StringVerifier : public TemplateVerifier<std::string> {
+    StringVerifier(bool mustBeNotEmpty = false);
+
+    TestResult operator()(const ghoul::Dictionary& dictionary,
+        const std::string& key) const override;
+
     std::string type() const override;
+
+    bool mustBeNotEmpty() const;
+
+private:
+    bool _mustBeNotEmpty = false;
 };
 
 /**

src/documentation/verifier.cpp

@@ -174,6 +174,33 @@ std::string IntVerifier::type() const {
     return "Integer";
 }
 
+StringVerifier::StringVerifier(bool mustBeNotEmpty)
+    : TemplateVerifier<std::string>()
+    , _mustBeNotEmpty(mustBeNotEmpty)
+{}
+
+TestResult StringVerifier::operator()(const ghoul::Dictionary& dictionary,
+                                      const std::string& key) const
+{
+    TestResult res = TemplateVerifier<std::string>::operator()(dictionary, key);
+    if (!res.success) {
+        return res;
+    }
+
+    std::string value = dictionary.value<std::string>(key);
+    if (value.empty() && _mustBeNotEmpty) {
+        res.success = false;
+        res.offenses.push_back({
+            key, TestResult::Offense::Reason::Verification, "value must not be empty"
+        });
+    }
+    return res;
+}
+
+bool StringVerifier::mustBeNotEmpty() const {
+    return _mustBeNotEmpty;
+}
+
 std::string StringVerifier::type() const {
     return "String";
 }

src/engine/logfactory.cpp

@@ -103,7 +103,6 @@ std::unique_ptr<ghoul::logging::Log> createLog(const ghoul::Dictionary& dictiona
     bool dateStamp = p.dateStamping.value_or(true);
     bool categoryStamp = p.categoryStamping.value_or(true);
     bool logLevelStamp = p.logLevelStamping.value_or(true);
-    Parameters::LogLevel logLevel = p.logLevel.value_or(Parameters::LogLevel::AllLogging);
     ghoul::logging::LogLevel level = [](Parameters::LogLevel l) {
         switch (l) {
             case Parameters::LogLevel::AllLogging: