util/OptionParser: pass array of OptionDefs to constructor

src/CommandLine.cxx

@@ -76,24 +76,29 @@
 #define USER_CONFIG_FILE_LOCATION_XDG PATH_LITERAL("mpd/mpd.conf")
 #endif
 
-static constexpr OptionDef opt_kill(
-	"kill", "kill the currently running mpd session");
-static constexpr OptionDef opt_no_config(
-	"no-config", "don't read from config");
-static constexpr OptionDef opt_no_daemon(
-	"no-daemon", "don't detach from console");
-static constexpr OptionDef opt_stdout(
-	"stdout", nullptr); // hidden, compatibility with old versions
-static constexpr OptionDef opt_stderr(
-	"stderr", "print messages to stderr");
-static constexpr OptionDef opt_verbose(
-	"verbose", 'v', "verbose logging");
-static constexpr OptionDef opt_version(
-	"version", 'V', "print version number");
-static constexpr OptionDef opt_help(
-	"help", 'h', "show help options");
-static constexpr OptionDef opt_help_alt(
-	nullptr, '?', nullptr); // hidden, standard alias for --help
+enum Option {
+	OPTION_KILL,
+	OPTION_NO_CONFIG,
+	OPTION_NO_DAEMON,
+	OPTION_STDOUT,
+	OPTION_STDERR,
+	OPTION_VERBOSE,
+	OPTION_VERSION,
+	OPTION_HELP,
+	OPTION_HELP2,
+};
+
+static constexpr OptionDef option_defs[] = {
+	{"kill", "kill the currently running mpd session"},
+	{"no-config", "don't read from config"},
+	{"no-daemon", "don't detach from console"},
+	{"stdout", nullptr}, // hidden, compatibility with old versions
+	{"stderr", "print messages to stderr"},
+	{"verbose", 'v', "verbose logging"},
+	{"version", 'V', "print version number"},
+	{"help", 'h', "show help options"},
+	{nullptr, '?', nullptr}, // hidden, standard alias for --help
+};
 
 static constexpr Domain cmdline_domain("cmdline");
 
@@ -265,13 +270,8 @@ static void help(void)
 	       "\n"
 	       "Options:\n");
 
-	PrintOption(opt_help);
-	PrintOption(opt_kill);
-	PrintOption(opt_no_config);
-	PrintOption(opt_no_daemon);
-	PrintOption(opt_stderr);
-	PrintOption(opt_verbose);
-	PrintOption(opt_version);
+	for (const auto &i : option_defs)
+		PrintOption(i);
 
 	exit(EXIT_SUCCESS);
 }
@@ -312,35 +312,38 @@ ParseCommandLine(int argc, char **argv, struct options *options)
 	options->verbose = false;
 
 	// First pass: handle command line options
-	OptionParser parser(argc, argv);
-	while (parser.ParseNext()) {
-		if (parser.CheckOption(opt_kill)) {
+	OptionParser parser(option_defs, argc, argv);
+	int option_index;
+	while ((option_index = parser.Next()) >= 0) {
+		switch (Option(option_index)) {
+		case OPTION_KILL:
 			options->kill = true;
-			continue;
-		}
-		if (parser.CheckOption(opt_no_config)) {
+			break;
+
+		case OPTION_NO_CONFIG:
 			use_config_file = false;
-			continue;
-		}
-		if (parser.CheckOption(opt_no_daemon)) {
+			break;
+
+		case OPTION_NO_DAEMON:
 			options->daemon = false;
-			continue;
-		}
-		if (parser.CheckOption(opt_stderr, opt_stdout)) {
+			break;
+
+		case OPTION_STDOUT:
+		case OPTION_STDERR:
 			options->log_stderr = true;
-			continue;
-		}
-		if (parser.CheckOption(opt_verbose)) {
+			break;
+
+		case OPTION_VERBOSE:
 			options->verbose = true;
-			continue;
-		}
-		if (parser.CheckOption(opt_version))
+			break;
+
+		case OPTION_VERSION:
 			version();
-		if (parser.CheckOption(opt_help, opt_help_alt))
-			help();
 
-		throw FormatRuntimeError("invalid option: %s",
-					 parser.GetOption());
+		case OPTION_HELP:
+		case OPTION_HELP2:
+			help();
+		}
 	}
 
 	/* initialize the logging library, so the configuration file

src/util/OptionParser.cxx

 /*
- * Copyright 2003-2017 The Music Player Daemon Project
+ * Copyright 2003-2018 The Music Player Daemon Project
  * http://www.musicpd.org
  *
  * This program is free software; you can redistribute it and/or modify
@@ -19,43 +19,41 @@
 
 #include "OptionParser.hxx"
 #include "OptionDef.hxx"
+#include "util/RuntimeError.hxx"
 
 #include <string.h>
 
-bool
-OptionParser::CheckOption(const OptionDef &opt) const noexcept
+inline unsigned
+OptionParser::IdentifyOption(const char *s) const
 {
-	assert(option != nullptr);
-
-	if (is_long)
-		return opt.HasLongOption() &&
-		       strcmp(option, opt.GetLongOption()) == 0;
+	assert(s != nullptr);
+	assert(*s == '-');
+
+	if (s[1] == '-') {
+		for (const auto &i : options)
+			if (i.HasLongOption() &&
+			    strcmp(s + 2, i.GetLongOption()) == 0)
+				return &i - options.data;
+	} else if (s[1] != 0 && s[2] == 0) {
+		const char ch = s[1];
+		for (const auto &i : options)
+			if (i.HasShortOption() && ch == i.GetShortOption())
+				return &i - options.data;
+	}
 
-	return opt.HasShortOption() &&
-	       option[0] == opt.GetShortOption() &&
-	       option[1] == '\0';
+	throw FormatRuntimeError("Unknown option: %s", s);
 }
 
-bool
-OptionParser::ParseNext() noexcept
+int
+OptionParser::Next()
 {
 	while (!args.empty()) {
 		const char *arg = args.shift();
-		if (arg[0] == '-') {
-			if (arg[1] == '-') {
-				option = arg + 2;
-				is_long = true;
-			}
-			else {
-				option = arg + 1;
-				is_long = false;
-			}
-			option_raw = arg;
-			return true;
-		}
+		if (arg[0] == '-')
+			return IdentifyOption(arg);
 
 		*remaining_tail++ = arg;
 	}
 
-	return false;
+	return -1;
 }

src/util/OptionParser.hxx

 /*
- * Copyright 2003-2017 The Music Player Daemon Project
+ * Copyright 2003-2018 The Music Player Daemon Project
  * http://www.musicpd.org
  *
  * This program is free software; you can redistribute it and/or modify
@@ -29,10 +29,9 @@ class OptionDef;
  */
 class OptionParser
 {
+	ConstBuffer<OptionDef> options;
+
 	ConstBuffer<const char *> args;
-	const char *option;
-	const char *option_raw;
-	bool is_long = false;
 
 	const char **const remaining_head, **remaining_tail;
 
@@ -40,41 +39,23 @@ public:
 	/**
 	 * Constructs #OptionParser.
 	 */
-	OptionParser(int _argc, char **_argv) noexcept
-		:args(_argv + 1, _argc - 1),
+	OptionParser(ConstBuffer<OptionDef> _options,
+		     int _argc, char **_argv) noexcept
+		:options(_options), args(_argv + 1, _argc - 1),
 		 remaining_head(const_cast<const char **>(_argv + 1)),
 		 remaining_tail(remaining_head) {}
 
 	/**
-	 * Gets the last parsed option.
-	 */
-	const char *GetOption() noexcept {
-		return option_raw;
-	}
-
-	/**
-	 * Checks if current option is a specified option.
-	 */
-	bool CheckOption(const OptionDef &opt) const noexcept;
-
-	/**
-	 * Checks if current option is a specified option
-	 * or specified alternative option.
-	 */
-	bool CheckOption(const OptionDef &opt,
-			 const OptionDef &alt_opt) const noexcept {
-		return CheckOption(opt) || CheckOption(alt_opt);
-	}
-
-	/**
 	 * Parses current command line entry.
 	 * Regardless of result, advances current position to the next
 	 * command line entry. 
 	 *
-	 * @return true if an option was found, false if there are no
-	 * more options
+	 * Throws on error.
+	 *
+	 * @return the index if an option was found, -1 if there are
+	 * no more options
 	 */
-	bool ParseNext() noexcept;
+	int Next();
 
 	/**
 	 * Returns the remaining non-option arguments.
@@ -82,6 +63,9 @@ public:
 	ConstBuffer<const char *> GetRemaining() const noexcept {
 		return {remaining_head, remaining_tail};
 	}
+
+private:
+	unsigned IdentifyOption(const char *s) const;
 };
 
 #endif