Move more command line parsing into a module

cli/command_line.cpp

@@ -30,6 +30,25 @@ namespace katja
         const std::vector<std::string> arguments;
     };
 
+    export struct search_command
+    {
+        const std::string needle;
+    };
+
+    export struct updates_command
+    {
+    };
+
+    export struct help_command
+    {
+    };
+
+    export using subcommand = std::variant<
+        search_command,
+        updates_command,
+        help_command
+    >;
+
     export class invalid_command_error : public std::runtime_error
     {
         const std::string command;
@@ -40,13 +59,26 @@ namespace katja
         {
         }
 
-        invalid_command_error(const std::string& invalid_command)
+        explicit invalid_command_error(const std::string& invalid_command)
             : command{ invalid_command },
             std::runtime_error("Unknown command given on the command line.")
         {
         }
     };
 
+    export class command_line_error : public std::runtime_error
+    {
+        boost::program_options::options_description description;
+
+    public:
+        command_line_error(const std::string& message,
+                boost::program_options::options_description&& description)
+            : description(std::move(description)),
+            std::runtime_error(message)
+        {
+        }
+    };
+
     export command_line parse_command_line(int argc, const char **argv)
     {
         if (argc == 1)
@@ -70,4 +102,42 @@ namespace katja
         }
         throw invalid_command_error(argv[1]);
     }
+
+    search_command parse_search_command(const std::vector<std::string>& arguments)
+    {
+        boost::program_options::options_description search_description("Search packages");
+        search_description
+            .add_options()("name", "Find packages by name");
+
+        boost::program_options::positional_options_description positional_arguments;
+        positional_arguments.add("name", 1);
+
+        boost::program_options::variables_map option_map;
+        auto command_parser = boost::program_options::command_line_parser(arguments)
+            .options(search_description).positional(positional_arguments);
+        boost::program_options::store(command_parser.run(), option_map);
+        boost::program_options::notify(option_map);
+
+        if (!option_map.count("name"))
+        {
+            throw command_line_error("Search string wasn't specified.",
+                    std::move(search_description));
+        }
+        return search_command{ option_map["name"].as<std::string>() };
+    }
+
+    export subcommand parse_subcommand(const command_line& subcommand_line)
+    {
+        switch (subcommand_line.type)
+        {
+        case command::updates:
+            return updates_command();
+        case command::search:
+            return parse_search_command(subcommand_line.arguments);
+        case command::help:
+            return help_command();
+        default:
+            std::unreachable();
+        }
+    }
 }

cli/configuration.cpp

@@ -26,7 +26,13 @@ export namespace katja
     class configuration
     {
     public:
-        using repositories_t = std::forward_list<std::pair<std::string, repository_configuration>>;
+        using value_type = std::pair<std::string, repository_configuration>;
+        using reference_type = value_type&;
+        using const_reference_type = const value_type&;
+
+        using repositories_t = std::forward_list<value_type>;
+        using size_type = repositories_t::size_type;
+        using difference_type = repositories_t::difference_type;
 
     private:
         repositories_t repositories;
@@ -47,6 +53,16 @@ export namespace katja
             return this->repositories.end();
         }
 
+        repositories_t::const_iterator begin() const
+        {
+            return this->repositories.begin();
+        }
+
+        repositories_t::const_iterator end() const
+        {
+            return this->repositories.end();
+        }
+
         repositories_t::const_iterator cbegin()
         {
             return this->repositories.cbegin();

cli/main.cpp

@@ -6,6 +6,7 @@
 #include <filesystem>
 #include <memory>
 #include <iostream>
+#include <variant>
 
 #include <boost/program_options.hpp>
 
@@ -36,14 +37,13 @@ static void search_names(std::shared_ptr<katja::repository> repository, const st
     }
 }
 
-int main(int argc, const char **argv)
+static void handle_subcommand(const katja::configuration& configuration,
+        const katja::subcommand& command)
 {
-    katja::configuration configuration = katja::read_configuration("katja.toml");
-    katja::package_database installed_database = katja::read_installed_database();
-
-    katja::command_line command_line = katja::parse_command_line(argc, argv);
-    if (command_line.type == katja::command::updates)
+    if (std::holds_alternative<katja::updates_command>(command))
     {
+        katja::package_database installed_database = katja::read_installed_database();
+
         for (const auto& [repository_name, repository_configuration] : configuration)
         {
             std::filesystem::path slackbuild_repository{ repository_configuration.path };
@@ -52,34 +52,25 @@ int main(int argc, const char **argv)
             get_updates(repository, std::move(installed_database));
         }
     }
-    else if (command_line.type == katja::command::search)
+    else if (std::holds_alternative<katja::search_command>(command))
     {
-        boost::program_options::options_description search_description("Search packages");
-        search_description
-            .add_options()("name", "Find packages by name");
-
-        boost::program_options::positional_options_description positional_arguments;
-        positional_arguments.add("name", 1);
-
-        boost::program_options::variables_map option_map;
-        auto command_parser = boost::program_options::command_line_parser(command_line.arguments)
-            .options(search_description).positional(positional_arguments);
-        boost::program_options::store(command_parser.run(), option_map);
-        boost::program_options::notify(option_map);
-
-        if (!option_map.count("name"))
-        {
-            std::cerr << search_description;
-            return EXIT_FAILURE;
-        }
         for (const auto& [repository_name, repository_configuration] : configuration)
         {
             std::filesystem::path slackbuild_repository{ repository_configuration.path };
             auto repository = std::make_shared<katja::sbo_repository>(slackbuild_repository);
 
-            search_names(repository, option_map["name"].as<std::string>());
+            search_names(repository, std::get<katja::search_command>(command).needle);
         }
     }
+}
+
+int main(int argc, const char **argv)
+{
+    katja::configuration configuration = katja::read_configuration("katja.toml");
+    katja::command_line command_line = katja::parse_command_line(argc, argv);
+    katja::subcommand subcommand = katja::parse_subcommand(command_line);
+
+    handle_subcommand(configuration, subcommand);
 
     return EXIT_SUCCESS;
 }