command/Request: add parser methods

src/command/DatabaseCommands.cxx

@@ -33,7 +33,6 @@
 #include "util/Error.hxx"
 #include "SongFilter.hxx"
 #include "protocol/Result.hxx"
-#include "protocol/ArgParser.hxx"
 #include "BulkEdit.hxx"
 
 #include <string.h>
@@ -54,7 +53,7 @@ CommandResult
 handle_lsinfo2(Client &client, Request args)
 {
 	/* default is root directory */
-	const char *const uri = args.IsEmpty() ? "" : args.front();
+	const auto uri = args.GetOptional(0, "");
 
 	const DatabaseSelection selection(uri, false);
 
@@ -70,7 +69,7 @@ handle_match(Client &client, Request args, bool fold_case)
 {
 	RangeArg window;
 	if (args.size >= 2 && strcmp(args[args.size - 2], "window") == 0) {
-		if (!ParseCommandArg(client, window, args.back()))
+		if (!args.Parse(args.size - 1, window, client))
 			return CommandResult::ERROR;
 
 		args.pop_back();
@@ -190,7 +189,7 @@ CommandResult
 handle_listall(Client &client, Request args)
 {
 	/* default is root directory */
-	const char *const uri = args.IsEmpty() ? "" : args.front();
+	const auto uri = args.GetOptional(0, "");
 
 	Error error;
 	return db_selection_print(client, DatabaseSelection(uri, true),
@@ -275,7 +274,7 @@ CommandResult
 handle_listallinfo(Client &client, Request args)
 {
 	/* default is root directory */
-	const char *const uri = args.IsEmpty() ? "" : args.front();
+	const auto uri = args.GetOptional(0, "");
 
 	Error error;
 	return db_selection_print(client, DatabaseSelection(uri, true),

src/command/OtherCommands.cxx

@@ -32,7 +32,6 @@
 #include "tag/TagHandler.hxx"
 #include "TimePrint.hxx"
 #include "decoder/DecoderPrint.hxx"
-#include "protocol/ArgParser.hxx"
 #include "protocol/Result.hxx"
 #include "ls.hxx"
 #include "mixer/Volume.hxx"
@@ -116,7 +115,7 @@ CommandResult
 handle_listfiles(Client &client, Request args)
 {
 	/* default is root directory */
-	const char *const uri = args.IsEmpty() ? "" : args.front();
+	const auto uri = args.GetOptional(0, "");
 
 	if (memcmp(uri, "file:///", 8) == 0)
 		/* list local directory */
@@ -155,7 +154,7 @@ CommandResult
 handle_lsinfo(Client &client, Request args)
 {
 	/* default is root directory */
-	const char *const uri = args.IsEmpty() ? "" : args.front();
+	const auto uri = args.GetOptional(0, "");
 
 	if (memcmp(uri, "file:///", 8) == 0) {
 		/* print information about an arbitrary local file */
@@ -309,7 +308,7 @@ CommandResult
 handle_setvol(Client &client, Request args)
 {
 	unsigned level;
-	if (!ParseCommandArg(client, level, args.front(), 100))
+	if (!args.Parse(0, level, client, 100))
 		return CommandResult::ERROR;
 
 	if (!volume_level_change(client.partition.outputs, level)) {
@@ -325,7 +324,7 @@ CommandResult
 handle_volume(Client &client, Request args)
 {
 	int relative;
-	if (!ParseCommandArg(client, relative, args.front(), -100, 100))
+	if (!args.Parse(0, relative, client,  -100, 100))
 		return CommandResult::ERROR;
 
 	const int old_volume = volume_level_get(client.partition.outputs);

src/command/OutputCommands.cxx

@@ -23,7 +23,6 @@
 #include "output/OutputPrint.hxx"
 #include "output/OutputCommand.hxx"
 #include "protocol/Result.hxx"
-#include "protocol/ArgParser.hxx"
 #include "client/Client.hxx"
 #include "Partition.hxx"
 #include "util/ConstBuffer.hxx"
@@ -34,7 +33,7 @@ handle_enableoutput(Client &client, Request args)
 	assert(args.size == 1);
 
 	unsigned device;
-	if (!ParseCommandArg(client, device, args.front()))
+	if (!args.Parse(0, device, client))
 		return CommandResult::ERROR;
 
 	if (!audio_output_enable_index(client.partition.outputs, device)) {
@@ -52,7 +51,7 @@ handle_disableoutput(Client &client, Request args)
 	assert(args.size == 1);
 
 	unsigned device;
-	if (!ParseCommandArg(client, device, args.front()))
+	if (!args.Parse(0, device, client))
 		return CommandResult::ERROR;
 
 	if (!audio_output_disable_index(client.partition.outputs, device)) {
@@ -70,7 +69,7 @@ handle_toggleoutput(Client &client, Request args)
 	assert(args.size == 1);
 
 	unsigned device;
-	if (!ParseCommandArg(client, device, args.front()))
+	if (!args.Parse(0, device, client))
 		return CommandResult::ERROR;
 
 	if (!audio_output_toggle_index(client.partition.outputs, device)) {

src/command/PlayerCommands.cxx

@@ -28,7 +28,6 @@
 #include "Partition.hxx"
 #include "Instance.hxx"
 #include "protocol/Result.hxx"
-#include "protocol/ArgParser.hxx"
 #include "AudioFormat.hxx"
 #include "ReplayGainConfig.hxx"
 #include "util/ConstBuffer.hxx"
@@ -61,7 +60,7 @@ CommandResult
 handle_play(Client &client, Request args)
 {
 	int song = -1;
-	if (!args.IsEmpty() && !ParseCommandArg(client, song, args.front()))
+	if (!args.ParseOptional(0, song, client))
 		return CommandResult::ERROR;
 
 	PlaylistResult result = client.partition.PlayPosition(song);
@@ -72,7 +71,7 @@ CommandResult
 handle_playid(Client &client, Request args)
 {
 	int id = -1;
-	if (!args.IsEmpty() && !ParseCommandArg(client, id, args.front()))
+	if (!args.ParseOptional(0, id, client))
 		return CommandResult::ERROR;
 
 	PlaylistResult result = client.partition.PlayId(id);
@@ -98,7 +97,7 @@ handle_pause(Client &client, Request args)
 {
 	if (!args.IsEmpty()) {
 		bool pause_flag;
-		if (!ParseCommandArg(client, pause_flag, args.front()))
+		if (!args.Parse(0, pause_flag, client))
 			return CommandResult::ERROR;
 
 		client.player_control.SetPause(pause_flag);
@@ -249,7 +248,7 @@ CommandResult
 handle_repeat(Client &client, Request args)
 {
 	bool status;
-	if (!ParseCommandArg(client, status, args.front()))
+	if (!args.Parse(0, status, client))
 		return CommandResult::ERROR;
 
 	client.partition.SetRepeat(status);
@@ -260,7 +259,7 @@ CommandResult
 handle_single(Client &client, Request args)
 {
 	bool status;
-	if (!ParseCommandArg(client, status, args.front()))
+	if (!args.Parse(0, status, client))
 		return CommandResult::ERROR;
 
 	client.partition.SetSingle(status);
@@ -271,7 +270,7 @@ CommandResult
 handle_consume(Client &client, Request args)
 {
 	bool status;
-	if (!ParseCommandArg(client, status, args.front()))
+	if (!args.Parse(0, status, client))
 		return CommandResult::ERROR;
 
 	client.partition.SetConsume(status);
@@ -282,7 +281,7 @@ CommandResult
 handle_random(Client &client, Request args)
 {
 	bool status;
-	if (!ParseCommandArg(client, status, args.front()))
+	if (!args.Parse(0, status, client))
 		return CommandResult::ERROR;
 
 	client.partition.SetRandom(status);
@@ -303,9 +302,9 @@ handle_seek(Client &client, Request args)
 	unsigned song;
 	SongTime seek_time;
 
-	if (!ParseCommandArg(client, song, args[0]))
+	if (!args.Parse(0, song, client))
 		return CommandResult::ERROR;
-	if (!ParseCommandArg(client, seek_time, args[1]))
+	if (!args.Parse(1, seek_time, client))
 		return CommandResult::ERROR;
 
 	PlaylistResult result =
@@ -318,9 +317,9 @@ handle_seekid(Client &client, Request args)
 {
 	unsigned id;
 	SongTime seek_time;
-	if (!ParseCommandArg(client, id, args[0]))
+	if (!args.Parse(0, id, client))
 		return CommandResult::ERROR;
-	if (!ParseCommandArg(client, seek_time, args[1]))
+	if (!args.Parse(1, seek_time, client))
 		return CommandResult::ERROR;
 
 	PlaylistResult result =
@@ -346,7 +345,7 @@ CommandResult
 handle_crossfade(Client &client, Request args)
 {
 	unsigned xfade_time;
-	if (!ParseCommandArg(client, xfade_time, args.front()))
+	if (!args.Parse(0, xfade_time, client))
 		return CommandResult::ERROR;
 
 	client.player_control.SetCrossFade(xfade_time);
@@ -357,7 +356,7 @@ CommandResult
 handle_mixrampdb(Client &client, Request args)
 {
 	float db;
-	if (!ParseCommandArg(client, db, args.front()))
+	if (!args.Parse(0, db, client))
 		return CommandResult::ERROR;
 
 	client.player_control.SetMixRampDb(db);
@@ -368,7 +367,7 @@ CommandResult
 handle_mixrampdelay(Client &client, Request args)
 {
 	float delay_secs;
-	if (!ParseCommandArg(client, delay_secs, args.front()))
+	if (!args.Parse(0, delay_secs, client))
 		return CommandResult::ERROR;
 
 	client.player_control.SetMixRampDelay(delay_secs);

src/command/PlaylistCommands.cxx

@@ -33,7 +33,6 @@
 #include "queue/Playlist.hxx"
 #include "TimePrint.hxx"
 #include "client/Client.hxx"
-#include "protocol/ArgParser.hxx"
 #include "protocol/Result.hxx"
 #include "ls.hxx"
 #include "Mapper.hxx"
@@ -71,10 +70,8 @@ handle_save(Client &client, Request args)
 CommandResult
 handle_load(Client &client, Request args)
 {
-	RangeArg range;
-	if (args.size < 2)
-		range.SetAll();
-	else if (!ParseCommandArg(client, range, args[1]))
+	RangeArg range = RangeArg::All();
+	if (!args.ParseOptional(1, range, client))
 		return CommandResult::ERROR;
 
 	const ScopeBulkEdit bulk_edit(client.partition);
@@ -146,7 +143,7 @@ handle_playlistdelete(Client &client, Request args)
 {
 	const char *const name = args[0];
 	unsigned from;
-	if (!ParseCommandArg(client, from, args[1]))
+	if (!args.Parse(1, from, client))
 		return CommandResult::ERROR;
 
 	Error error;
@@ -160,9 +157,8 @@ handle_playlistmove(Client &client, Request args)
 {
 	const char *const name = args.front();
 	unsigned from, to;
-	if (!ParseCommandArg(client, from, args[1]))
-		return CommandResult::ERROR;
-	if (!ParseCommandArg(client, to, args[2]))
+	if (!args.Parse(1, from, client) ||
+	    !args.Parse(2, to, client))
 		return CommandResult::ERROR;
 
 	Error error;

src/command/QueueCommands.cxx

@@ -30,7 +30,6 @@
 #include "client/Client.hxx"
 #include "Partition.hxx"
 #include "BulkEdit.hxx"
-#include "protocol/ArgParser.hxx"
 #include "protocol/Result.hxx"
 #include "ls.hxx"
 #include "util/ConstBuffer.hxx"
@@ -105,8 +104,9 @@ handle_addid(Client &client, Request args)
 
 	if (args.size == 2) {
 		unsigned to;
-		if (!ParseCommandArg(client, to, args[1]))
+		if (!args.Parse(1, to, client))
 			return CommandResult::ERROR;
+
 		PlaylistResult result = client.partition.MoveId(added_id, to);
 		if (result != PlaylistResult::SUCCESS) {
 			CommandResult ret =
@@ -155,7 +155,7 @@ CommandResult
 handle_rangeid(Client &client, Request args)
 {
 	unsigned id;
-	if (!ParseCommandArg(client, id, args.front()))
+	if (!args.Parse(0, id, client))
 		return CommandResult::ERROR;
 
 	SongTime start, end;
@@ -177,7 +177,7 @@ CommandResult
 handle_delete(Client &client, Request args)
 {
 	RangeArg range;
-	if (!ParseCommandArg(client, range, args.front()))
+	if (!args.Parse(0, range, client))
 		return CommandResult::ERROR;
 
 	auto result = client.partition.DeleteRange(range.start, range.end);
@@ -188,7 +188,7 @@ CommandResult
 handle_deleteid(Client &client, Request args)
 {
 	unsigned id;
-	if (!ParseCommandArg(client, id, args.front()))
+	if (!args.Parse(0, id, client))
 		return CommandResult::ERROR;
 
 	PlaylistResult result = client.partition.DeleteId(id);
@@ -205,10 +205,8 @@ handle_playlist(Client &client, gcc_unused Request args)
 CommandResult
 handle_shuffle(gcc_unused Client &client, Request args)
 {
-	RangeArg range;
-	if (args.IsEmpty())
-		range.SetAll();
-	else if (!ParseCommandArg(client, range, args.front()))
+	RangeArg range = RangeArg::All();
+	if (!args.ParseOptional(0, range, client))
 		return CommandResult::ERROR;
 
 	client.partition.Shuffle(range.start, range.end);
@@ -249,10 +247,8 @@ handle_plchangesposid(Client &client, Request args)
 CommandResult
 handle_playlistinfo(Client &client, Request args)
 {
-	RangeArg range;
-	if (args.IsEmpty())
-		range.SetAll();
-	else if (!ParseCommandArg(client, range, args.front()))
+	RangeArg range = RangeArg::All();
+	if (!args.ParseOptional(0, range, client))
 		return CommandResult::ERROR;
 
 	if (!playlist_print_info(client, client.playlist,
@@ -268,7 +264,7 @@ handle_playlistid(Client &client, Request args)
 {
 	if (!args.IsEmpty()) {
 		unsigned id;
-		if (!ParseCommandArg(client, id, args.front()))
+		if (!args.Parse(0, id, client))
 			return CommandResult::ERROR;
 
 		bool ret = playlist_print_id(client, client.playlist, id);
@@ -312,9 +308,8 @@ handle_playlistsearch(Client &client, Request args)
 CommandResult
 handle_prio(Client &client, Request args)
 {
-	const char *const priority_string = args.shift();
 	unsigned priority;
-	if (!ParseCommandArg(client, priority, priority_string, 0xff))
+	if (!args.ParseShift(0, priority, client, 0xff))
 		return CommandResult::ERROR;
 
 	for (const char *i : args) {
@@ -336,9 +331,8 @@ handle_prio(Client &client, Request args)
 CommandResult
 handle_prioid(Client &client, Request args)
 {
-	const char *const priority_string = args.shift();
 	unsigned priority;
-	if (!ParseCommandArg(client, priority, priority_string, 0xff))
+	if (!args.ParseShift(0, priority, client, 0xff))
 		return CommandResult::ERROR;
 
 	for (const char *i : args) {
@@ -361,8 +355,8 @@ handle_move(Client &client, Request args)
 	RangeArg range;
 	int to;
 
-	if (!ParseCommandArg(client, range, args[0]) ||
-	    !ParseCommandArg(client, to, args[1]))
+	if (!args.Parse(0, range, client) ||
+	    !args.Parse(1, to, client))
 		return CommandResult::ERROR;
 
 	PlaylistResult result =
@@ -375,8 +369,8 @@ handle_moveid(Client &client, Request args)
 {
 	unsigned id;
 	int to;
-	if (!ParseCommandArg(client, id, args[0]) ||
-	    !ParseCommandArg(client, to, args[1]))
+	if (!args.Parse(0, id, client) ||
+	    !args.Parse(1, to, client))
 		return CommandResult::ERROR;
 
 	PlaylistResult result = client.partition.MoveId(id, to);
@@ -387,8 +381,8 @@ CommandResult
 handle_swap(Client &client, Request args)
 {
 	unsigned song1, song2;
-	if (!ParseCommandArg(client, song1, args[0]) ||
-	    !ParseCommandArg(client, song2, args[1]))
+	if (!args.Parse(0, song1, client) ||
+	    !args.Parse(1, song2, client))
 		return CommandResult::ERROR;
 
 	PlaylistResult result =
@@ -400,8 +394,8 @@ CommandResult
 handle_swapid(Client &client, Request args)
 {
 	unsigned id1, id2;
-	if (!ParseCommandArg(client, id1, args[0]) ||
-	    !ParseCommandArg(client, id2, args[1]))
+	if (!args.Parse(0, id1, client) ||
+	    !args.Parse(1, id2, client))
 		return CommandResult::ERROR;
 
 	PlaylistResult result = client.partition.SwapIds(id1, id2);

src/command/Request.hxx

@@ -21,14 +21,54 @@
 #define MPD_REQUEST_HXX
 
 #include "check.h"
+#include "protocol/ArgParser.hxx"
 #include "util/ConstBuffer.hxx"
 
+#include <utility>
+
+#include <assert.h>
+
+class Client;
+
 class Request : public ConstBuffer<const char *> {
 	typedef ConstBuffer<const char *> Base;
 
 public:
 	constexpr Request(const char *const*argv, size_type n)
 		:Base(argv, n) {}
+
+	constexpr const char *GetOptional(unsigned idx,
+					  const char *default_value=nullptr) const {
+		return idx < size
+			     ? data[idx]
+			     : default_value;
+	}
+
+	template<typename T, typename... Args>
+	bool Parse(unsigned idx, T &value_r, Client &client,
+		   Args&&... args) {
+		assert(idx < size);
+
+		return ParseCommandArg(client, value_r, data[idx],
+				       std::forward<Args>(args)...);
+	}
+
+	template<typename T, typename... Args>
+	bool ParseOptional(unsigned idx, T &value_r, Client &client,
+			   Args&&... args) {
+		return idx >= size ||
+			Parse(idx, value_r, client,
+			      std::forward<Args>(args)...);
+	}
+
+	template<typename T, typename... Args>
+	bool ParseShift(unsigned idx, T &value_r, Client &client,
+			Args&&... args) {
+		bool success = Parse(idx, value_r, client,
+				     std::forward<Args>(args)...);
+		shift();
+		return success;
+	}
 };
 
 #endif

src/command/TagCommands.cxx

@@ -22,7 +22,6 @@
 #include "Request.hxx"
 #include "CommandError.hxx"
 #include "client/Client.hxx"
-#include "protocol/ArgParser.hxx"
 #include "protocol/Result.hxx"
 #include "tag/Tag.hxx"
 #include "Partition.hxx"
@@ -32,7 +31,7 @@ CommandResult
 handle_addtagid(Client &client, Request args)
 {
 	unsigned song_id;
-	if (!ParseCommandArg(client, song_id, args.front()))
+	if (!args.Parse(0, song_id, client))
 		return CommandResult::ERROR;
 
 	const char *const tag_name = args[1];
@@ -57,7 +56,7 @@ CommandResult
 handle_cleartagid(Client &client, Request args)
 {
 	unsigned song_id;
-	if (!ParseCommandArg(client, song_id, args.front()))
+	if (!args.Parse(0, song_id, client))
 		return CommandResult::ERROR;
 
 	TagType tag_type = TAG_NUM_OF_ITEM_TYPES;

src/protocol/ArgParser.hxx

@@ -47,6 +47,10 @@ struct RangeArg {
 		start = 0;
 		end = std::numeric_limits<unsigned>::max();
 	}
+
+	static constexpr RangeArg All() {
+		return { 0, std::numeric_limits<unsigned>::max() };
+	}
 };
 
 bool