utils: refactor command-line arguments parsing

+ update usage messages.

1 files changed, 86 insertions, 0 deletions

diff --git a/utils/helpers/command_line.hpp b/utils/helpers/command_line.hpp
new file mode 100644
index 0000000..4843a06
--- /dev/null
+++ b/utils/helpers/command_line.hpp
@@ -0,0 +1,86 @@
+// Copyright (c) 2017 Egor Tensin <Egor.Tensin@gmail.com>
+// This file is part of the "AES tools" project.
+// For details, see https://github.com/egor-tensin/aes-tools.
+// Distributed under the MIT License.
+
+#pragma once
+
+#include <boost/filesystem.hpp>
+#include <boost/program_options.hpp>
+
+#include <exception>
+#include <iostream>
+#include <ostream>
+#include <string>
+
+namespace command_line
+{
+    class SettingsParser
+    {
+    public:
+        explicit SettingsParser(const std::string& argv0)
+            : prog_name{extract_filename(argv0)}
+        {
+            visible.add_options()
+                ("help,h",
+                    "show this message and exit");
+        }
+
+        virtual ~SettingsParser() = default;
+
+        virtual const char* get_short_description() const
+        {
+            return "[--option VALUE]...";
+        }
+
+        virtual void parse(int argc, char* argv[])
+        {
+            boost::program_options::options_description all;
+            all.add(hidden).add(visible);
+            boost::program_options::variables_map vm;
+            boost::program_options::store(
+                boost::program_options::command_line_parser{argc, argv}
+                    .options(all)
+                    .positional(positional)
+                    .run(),
+                vm);
+            if (vm.count("help"))
+                exit_with_usage = true;
+            else
+                boost::program_options::notify(vm);
+        }
+
+        bool exit_with_usage = false;
+
+        void usage() const
+        {
+            std::cout << *this;
+        }
+
+        void usage_error(const std::exception& e) const
+        {
+            std::cerr << "usage error: " << e.what() << '\n';
+            std::cerr << *this;
+        }
+
+    protected:
+        boost::program_options::options_description hidden;
+        boost::program_options::options_description visible;
+        boost::program_options::positional_options_description positional;
+
+        static std::string extract_filename(const std::string& path)
+        {
+            return boost::filesystem::path{path}.filename().string();
+        }
+
+        const std::string prog_name;
+
+        friend std::ostream& operator<<(std::ostream& os, const SettingsParser& parser)
+        {
+            const auto short_descr = parser.get_short_description();
+            os << "usage: " << parser.prog_name << ' ' << short_descr << '\n';
+            os << parser.visible;
+            return os;
+        }
+    };
+}