ReplayGainMode: add ToString(), FromString()

Move code from ReplayGainConfig.cxx.

Makefile.am

@@ -853,7 +853,7 @@ libbasic_a_SOURCES = \
 	src/CheckAudioFormat.cxx src/CheckAudioFormat.hxx \
 	src/AudioFormat.cxx src/AudioFormat.hxx \
 	src/AudioParser.cxx src/AudioParser.hxx \
-	src/ReplayGainMode.hxx \
+	src/ReplayGainMode.cxx src/ReplayGainMode.hxx \
 	src/ReplayGainInfo.cxx src/ReplayGainInfo.hxx
 
 # configuration library

src/ReplayGainConfig.cxx

@@ -22,10 +22,10 @@
 #include "config/Param.hxx"
 #include "config/ConfigGlobal.hxx"
 #include "system/FatalError.hxx"
+#include "util/RuntimeError.hxx"
 
 #include <assert.h>
 #include <stdlib.h>
-#include <string.h>
 #include <math.h>
 
 ReplayGainMode replay_gain_mode = ReplayGainMode::OFF;
@@ -36,54 +36,16 @@ float replay_gain_preamp = 1.0;
 float replay_gain_missing_preamp = 1.0;
 bool replay_gain_limit = DEFAULT_REPLAYGAIN_LIMIT;
 
-const char *
-replay_gain_get_mode_string(void)
-{
-	switch (replay_gain_mode) {
-	case ReplayGainMode::AUTO:
-		return "auto";
-
-	case ReplayGainMode::OFF:
-		return "off";
-
-	case ReplayGainMode::TRACK:
-		return "track";
-
-	case ReplayGainMode::ALBUM:
-		return "album";
-	}
-
-	assert(false);
-	gcc_unreachable();
-}
-
-bool
-replay_gain_set_mode_string(const char *p)
-{
-	assert(p != nullptr);
-
-	if (strcmp(p, "off") == 0)
-		replay_gain_mode = ReplayGainMode::OFF;
-	else if (strcmp(p, "track") == 0)
-		replay_gain_mode = ReplayGainMode::TRACK;
-	else if (strcmp(p, "album") == 0)
-		replay_gain_mode = ReplayGainMode::ALBUM;
-	else if (strcmp(p, "auto") == 0)
-		replay_gain_mode = ReplayGainMode::AUTO;
-	else
-		return false;
-
-	return true;
-}
-
 void replay_gain_global_init(void)
 {
 	const auto *param = config_get_param(ConfigOption::REPLAYGAIN);
 
-	if (param != nullptr &&
-	    !replay_gain_set_mode_string(param->value.c_str())) {
-		FormatFatalError("replaygain value \"%s\" at line %i is invalid\n",
-				 param->value.c_str(), param->line);
+	try {
+		if (param != nullptr)
+			replay_gain_mode = FromString(param->value.c_str());
+	} catch (...) {
+		std::throw_with_nested(FormatRuntimeError("Failed to parse line %i",
+							  param->line));
 	}
 
 	param = config_get_param(ConfigOption::REPLAYGAIN_PREAMP);

src/ReplayGainConfig.hxx

@@ -22,7 +22,6 @@
 
 #include "check.h"
 #include "ReplayGainMode.hxx"
-#include "Compiler.h"
 
 extern ReplayGainMode replay_gain_mode;
 extern float replay_gain_preamp;
@@ -32,19 +31,4 @@ extern bool replay_gain_limit;
 void
 replay_gain_global_init();
 
-/**
- * Returns the current replay gain mode as a machine-readable string.
- */
-gcc_pure
-const char *
-replay_gain_get_mode_string();
-
-/**
- * Sets the replay gain mode, parsed from a string.
- *
- * @return true on success, false if the string could not be parsed
- */
-bool
-replay_gain_set_mode_string(const char *p);
-
 #endif

src/ReplayGainMode.cxx

@@ -0,0 +1,63 @@
+/*
+ * Copyright 2003-2016 The Music Player Daemon Project
+ * http://www.musicpd.org
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include "ReplayGainMode.hxx"
+
+#include <stdexcept>
+
+#include <assert.h>
+#include <string.h>
+
+const char *
+ToString(ReplayGainMode mode)
+{
+	switch (mode) {
+	case ReplayGainMode::AUTO:
+		return "auto";
+
+	case ReplayGainMode::OFF:
+		return "off";
+
+	case ReplayGainMode::TRACK:
+		return "track";
+
+	case ReplayGainMode::ALBUM:
+		return "album";
+	}
+
+	assert(false);
+	gcc_unreachable();
+}
+
+ReplayGainMode
+FromString(const char *s)
+{
+	assert(s != nullptr);
+
+	if (strcmp(s, "off") == 0)
+		return ReplayGainMode::OFF;
+	else if (strcmp(s, "track") == 0)
+		return ReplayGainMode::TRACK;
+	else if (strcmp(s, "album") == 0)
+		return ReplayGainMode::ALBUM;
+	else if (strcmp(s, "auto") == 0)
+		return ReplayGainMode::AUTO;
+	else
+		throw std::invalid_argument("Unrecognized replay gain mode");
+}

src/ReplayGainMode.hxx

@@ -20,6 +20,8 @@
 #ifndef MPD_REPLAY_GAIN_MODE_HXX
 #define MPD_REPLAY_GAIN_MODE_HXX
 
+#include "Compiler.h"
+
 #include <stdint.h>
 
 enum class ReplayGainMode : uint8_t {
@@ -29,4 +31,19 @@ enum class ReplayGainMode : uint8_t {
 	AUTO,
 };
 
+/**
+ * Return the string representation of a #ReplayGainMode.
+ */
+gcc_pure
+const char *
+ToString(ReplayGainMode mode);
+
+/**
+ * Parse a string to a #ReplayGainMode.  Throws std::runtime_error on
+ * error.
+ */
+gcc_pure
+ReplayGainMode
+FromString(const char *s);
+
 #endif

src/command/PlayerCommands.cxx

@@ -331,13 +331,9 @@ handle_mixrampdelay(Client &client, Request args, gcc_unused Response &r)
 }
 
 CommandResult
-handle_replay_gain_mode(Client &client, Request args, Response &r)
+handle_replay_gain_mode(Client &client, Request args, Response &)
 {
-	if (!replay_gain_set_mode_string(args.front())) {
-		r.Error(ACK_ERROR_ARG, "Unrecognized replay gain mode");
-		return CommandResult::ERROR;
-	}
-
+	replay_gain_mode = FromString(args.front());
 	client.partition.UpdateEffectiveReplayGainMode(replay_gain_mode);
 	client.partition.EmitIdle(IDLE_OPTIONS);
 	return CommandResult::OK;
@@ -347,6 +343,6 @@ CommandResult
 handle_replay_gain_status(gcc_unused Client &client, gcc_unused Request args,
 			  Response &r)
 {
-	r.Format("replay_gain_mode: %s\n", replay_gain_get_mode_string());
+	r.Format("replay_gain_mode: %s\n", ToString(replay_gain_mode));
 	return CommandResult::OK;
 }