Big YAML parser cleanup

src/yaml/parsers.hh

@@ -0,0 +1,99 @@
+/* parsers.hh
+ * vim: set tw=80:
+ * Eryn Wells <eryn@erynwells.me>
+ */
+/**
+ * Some top-level YAML parser objects.
+ */
+
+#ifndef __YAML_PARSERS_HH__
+#define __YAML_PARSERS_HH__
+
+#include <functional>
+#include <stack>
+
+#include "yaml.h"
+
+#include "scene.h"
+
+
+namespace yaml {
+
+struct Parser;
+typedef std::stack<Parser*> ParserStack;
+
+
+/**
+ * A Parser handles parsing a chunk of YAML, updating its mScene member as
+ * necessary.
+ */
+struct Parser
+{
+    /** Constructor */
+    Parser(Scene& scene, ParserStack& parsers);
+
+    /** Destructor */
+    virtual ~Parser();
+
+    /**
+     * Called by the parser event loop to handle a libyaml parser event.
+     *
+     * @param [in] event A libyaml parser event object
+     */
+    virtual void HandleEvent(yaml_event_t& event);
+
+
+    /** Set the done flag. */
+    void SetDone(bool done);
+
+    /**
+     * Returns true if the parser is done parsing.
+     *
+     * @returns `true` if done, `false` if not
+     */
+    bool GetDone() const;
+
+protected:
+    Scene& GetScene() const;
+    ParserStack& GetParsers() const;
+
+private:
+    /** The Scene being described by the YAML this parser is parsing. */
+    Scene& mScene;
+
+    /** The stack of parsers. */
+    ParserStack& mParsers;
+
+    /** `true` if the parser is done parsing */
+    bool mDone;
+};
+
+
+/**
+ * UtilityParsers handle small reusable bits of YAML and their constructors take
+ * a C++11 lambda, which will be called back with the result of the parsed data.
+ */
+template<typename CallbackType>
+struct UtilityParser
+    : public Parser
+{
+    typedef std::function<CallbackType> CallbackFunction;
+
+    UtilityParser(Scene& scene,
+                  ParserStack& parsers,
+                  CallbackFunction callback)
+        : Parser(scene, parsers),
+          mCallback(callback)
+    { }
+
+    virtual
+    ~UtilityParser()
+    { }
+
+private:
+    CallbackFunction mCallback;
+};
+
+} /* namespace yaml */
+
+#endif /* __YAML_PARSERS_HH__ */