Closes #13

core/dbc_statement_handler.h

@@ -3,7 +3,9 @@
 #define DBC_STATEMENT_HANDLER_H
 
 #include "dbc_database.h"
+#include "dbc_diagnostic.h"
 #include "typefactory.h"
+#include <stdexcept>
 #include <string>
 #include <unordered_map>
 
@@ -15,6 +17,17 @@ struct PendingValueDescriptions {
     std::size_t lineNumber;
 };
 
+/** Carries deferred validation locations without parsing exception text. */
+class DbcDiagnosticError : public std::runtime_error {
+public:
+    DbcDiagnosticError(DbcDiagnosticCode code, const std::string &filePath,
+                       std::size_t lineNumber, const std::string &message)
+        : std::runtime_error(filePath + ":" + std::to_string(lineNumber) + ": " + message),
+          diagnostic{DbcDiagnosticSeverity::Error, code, filePath, lineNumber, message} {}
+
+    DbcDiagnostic diagnostic;
+};
+
 /** Mutable state belonging to one file parse. Handlers do not retain it. */
 struct DbcParseContext {
     DbcDatabase &database;
@@ -68,6 +81,12 @@ public:
     void Handle(const std::string &line, DbcParseContext &context) const override;
 };
 
+/** Common header metadata does not change the supported decode definitions. */
+class DbcHeaderHandler : public DbcStatementHandler {
+public:
+    void Handle(const std::string &line, DbcParseContext &context) const override;
+};
+
 /** Exact-key dispatch to handlers created once per registration via TypeFactory. */
 class DbcStatementDispatcher {
 public: