Command.hh

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#ifndef COMMAND_HH
#define COMMAND_HH
 
#include "Completer.hh"
#include "strCat.hh"
#include "CommandException.hh"
#include <cassert>
#include <span>
#include <string_view>
#include <vector>
 
namespace openmsx {
 
class CommandController;
class GlobalCommandController;
class Interpreter;
class TclObject;
class CliComm;
 
class CommandCompleter : public Completer
{
public:
        CommandCompleter(const CommandCompleter&) = delete;
        CommandCompleter& operator=(const CommandCompleter&) = delete;
 
        [[nodiscard]] CommandController& getCommandController() const { return commandController; }
        [[nodiscard]] Interpreter& getInterpreter() const final;
 
protected:
        CommandCompleter(CommandController& controller, std::string_view name);
        ~CommandCompleter();
 
        [[nodiscard]] GlobalCommandController& getGlobalCommandController() const;
        [[nodiscard]] CliComm& getCliComm() const;
 
private:
        CommandController& commandController;
};
 
 
class Command : public CommandCompleter
{
        struct UnknownSubCommand {};
 
public:
        virtual void execute(std::span<const TclObject> tokens, TclObject& result) = 0;
 
        void tabCompletion(std::vector<std::string>& tokens) const override;
 
        // see comments in MSXMotherBoard::loadMachineCommand
        void setAllowedInEmptyMachine(bool value) { allowInEmptyMachine = value; }
        [[nodiscard]] bool isAllowedInEmptyMachine() const { return allowInEmptyMachine; }
 
        // used by Interpreter::(un)registerCommand()
        void setToken(void* token_) { assert(!token); token = token_; }
        [[nodiscard]] void* getToken() const { return token; }
 
        // helper to delegate to a subcommand
        template<typename... Args>
        void executeSubCommand(std::string_view subCmd, Args&&... args) {
                try {
                        executeSubCommandImpl(subCmd, std::forward<Args>(args)...);
                } catch (UnknownSubCommand) {
                        unknownSubCommand(subCmd, std::forward<Args>(args)...);
                }
        }
 
protected:
        Command(CommandController& controller, std::string_view name);
        ~Command();
 
private:
        template<typename Func, typename... Args>
        void executeSubCommandImpl(std::string_view subCmd, std::string_view candidate, Func func, Args&&... args) {
                if (subCmd == candidate) {
                        func();
                } else {
                        executeSubCommandImpl(subCmd, std::forward<Args>(args)...);
                }
        }
        void executeSubCommandImpl(std::string_view /*subCmd*/) {
                throw UnknownSubCommand{}; // exhausted all possible candidates
        }
 
        template<typename Func, typename... Args>
        void unknownSubCommand(std::string_view subCmd, std::string_view firstCandidate, Func /*func*/, Args&&... args) {
                unknownSubCommandImpl(strCat("Unknown subcommand '", subCmd, "'. Must be one of '", firstCandidate, '\''),
                                      std::forward<Args>(args)...);
        }
        template<typename Func, typename... Args>
        void unknownSubCommandImpl(std::string message, std::string_view candidate, Func /*func*/, Args&&... args) {
                strAppend(message, ", '", candidate, '\'');
                unknownSubCommandImpl(message, std::forward<Args>(args)...);
                throw SyntaxError();
        }
        template<typename Func>
        void unknownSubCommandImpl(std::string message, std::string_view lastCandidate, Func /*func*/) {
                strAppend(message, " or '", lastCandidate, "'.");
                throw CommandException(message);
        }
 
private:
        bool allowInEmptyMachine = true;
        void* token = nullptr;
};
 
} // namespace openmsx
 
#endif