Add Parser for setTargetState Command

This new method does the usual input validation. As only three values
are allowed for the only parameter “newstate”, they are explicitly
checked, because “never trust your clients”...

src/command.cpp

@@ -77,6 +77,8 @@ Command Command::fromString(const QString& source)
             return parseStoreToken(rootobj);
         case Action::updateExperimentState:
             return parseUpdateExperimentState(rootobj);
+        case Action::setTargetState:
+            return parseSetTargetState(rootobj);
         case Action::sendHistogramUpdate:
         case Action::moveTargetCloser:
         case Action::moveTargetFarther:
@@ -91,7 +93,6 @@ Command Command::fromString(const QString& source)
         // Not yet implemented:
         case Action::queryServerInformation:
         case Action::updateHistogram:
-        case Action::setTargetState:
         case Action::fillHistogram:
             return Command();
         default:
@@ -207,6 +208,26 @@ Protocol::Command Protocol::Command::parseUpdateExperimentState(const QJsonObjec
            );
 }
 
+Protocol::Command Protocol::Command::parseSetTargetState(const QJsonObject& input)
+{
+    if (!input.keys().contains(QStringLiteral("newstate")) || !input.value(QStringLiteral("newstate")).isString()) {
+        logError(QStringLiteral("setTargetState command does not contain newstate."));
+        return Command();
+    }
+    if (input.value(QStringLiteral("newstate")).toString() != QStringLiteral("open")
+            && input.value(QStringLiteral("newstate")).toString() != QStringLiteral("closed")
+            && input.value(QStringLiteral("newstate")).toString() != QStringLiteral("goldfoil")) {
+        logError(QStringLiteral("newstate parameter of setTargetState command is invalid."));
+        return Command();
+    }
+
+    return Command(
+               Action::setTargetState,
+               Arguments{std::make_pair(QStringLiteral("newstate"), input.value(QStringLiteral("newstate")).toString())},
+               input.value(QStringLiteral("token")).toString()
+           );
+}
+
 QString Command::toString() const
 {
     if (action == Action::invalid)

src/command.h

@@ -73,6 +73,7 @@ private:
     static Command parseStoreToken(const QJsonObject& input);
     static Command parseError(const QJsonObject& input);
     static Command parseUpdateExperimentState(const QJsonObject& input);
+    static Command parseSetTargetState(const QJsonObject& input);
 
     static QString getActionString(const Action action);
 };