Closes #11

core/dbc_statement_handler.h

@@ -0,0 +1,65 @@
+// SPDX-License-Identifier: MIT
+#ifndef DBC_STATEMENT_HANDLER_H
+#define DBC_STATEMENT_HANDLER_H
+
+#include "dbc_database.h"
+#include "typefactory.h"
+#include <string>
+#include <unordered_map>
+
+/** Mutable state belonging to one file parse. Handlers do not retain it. */
+struct DbcParseContext {
+    DbcDatabase &database;
+    FrameInfo *currentFrame = nullptr;
+};
+
+class DbcStatementHandler {
+public:
+    virtual ~DbcStatementHandler() = default;
+    virtual void Handle(const std::string &line, DbcParseContext &context) const = 0;
+};
+
+class DbcFrameHandler : public DbcStatementHandler {
+public:
+    void Handle(const std::string &line, DbcParseContext &context) const override;
+
+private:
+    static FrameInfo ParseFrameLine(const std::string &line);
+};
+
+class DbcSignalHandler : public DbcStatementHandler {
+public:
+    void Handle(const std::string &line, DbcParseContext &context) const override;
+
+private:
+    static SignalInfo ParseSignalLine(const std::string &line);
+};
+
+class DbcCommentHandler : public DbcStatementHandler {
+public:
+    void Handle(const std::string &line, DbcParseContext &context) const override;
+
+private:
+    static void ParseCommentLine(const std::string &line, DbcDatabase &database);
+};
+
+/** Exact-key dispatch to handlers created once per registration via TypeFactory. */
+class DbcStatementDispatcher {
+public:
+    DbcStatementDispatcher();
+
+    template<class Handler>
+    void RegisterType(const std::string &keyword) {
+        m_factory.registerType<Handler>(keyword);
+        m_handlers.insert_or_assign(keyword, m_factory.create(keyword));
+    }
+
+    /** Returns false for an unregistered keyword; input must be trimmed. */
+    bool Dispatch(const std::string &line, DbcParseContext &context) const;
+
+private:
+    TypeFactory<std::string, DbcStatementHandler> m_factory;
+    std::unordered_map<std::string, std::shared_ptr<DbcStatementHandler>> m_handlers;
+};
+
+#endif /* DBC_STATEMENT_HANDLER_H */