release v0.22.6

If the constructor moves from an ExportedSong instance which refers to
somebody else's "Tag" instance, the newly constructed instance will
instead refer to its own empty "tag_buffer" field.  This broke
SimpleDatabase::GetSong(), i.e. all songs on the queue restored from
the state file or added using the "addid" command.

Closes https://github.com/MusicPlayerDaemon/MPD/issues/1089

NEWS

@@ -1,3 +1,24 @@
+ver 0.22.6 (2021/02/16)
+* fix missing tags on songs in queue
+
+ver 0.22.5 (2021/02/15)
+* protocol
+  - error for malformed ranges instead of ignoring silently
+  - better error message for open-ended range with "move"
+* database
+  - simple: fix missing CUE sheet metadata in "addid" command
+* tags
+  - id: translate TPE3 to Conductor, not Performer
+* archive
+  - iso9660: another fix for unaligned reads
+* output
+  - httpd: error handling on Windows improved
+  - pulse: fix deadlock with "always_on"
+* Windows:
+  - enable https:// support (via Schannel)
+* Android
+  - work around "Permission denied" on mpd.conf
+
 ver 0.22.4 (2021/01/21)
 * protocol
   - add command "binarylimit" to allow larger chunk sizes

android/AndroidManifest.xml

@@ -2,10 +2,10 @@
 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
           package="org.musicpd"
           android:installLocation="auto"
-          android:versionCode="51"
+          android:versionCode="54"
-          android:versionName="0.22.1">
+          android:versionName="0.22.6">
 
-  <uses-sdk android:minSdkVersion="21" android:targetSdkVersion="28"/>
+  <uses-sdk android:minSdkVersion="21" android:targetSdkVersion="29"/>
 
   <uses-feature android:name="android.software.leanback"
                 android:required="false" />
@@ -19,6 +19,7 @@
   <uses-permission android:name="android.permission.FOREGROUND_SERVICE" />
 
   <application android:allowBackup="true"
+               android:requestLegacyExternalStorage="true"
                android:icon="@drawable/icon"
                android:banner="@drawable/icon"
                android:label="@string/app_name">

android/meson.build

@@ -5,8 +5,8 @@ android_ndk = get_option('android_ndk')
 android_sdk = get_option('android_sdk')
 android_abi = get_option('android_abi')
 
-android_sdk_build_tools_version = '27.0.0'
+android_sdk_build_tools_version = '29.0.3'
-android_sdk_platform = 'android-23'
+android_sdk_platform = 'android-29'
 
 android_build_tools_dir = join_paths(android_sdk, 'build-tools', android_sdk_build_tools_version)
 android_sdk_platform_dir = join_paths(android_sdk, 'platforms', android_sdk_platform)

doc/conf.py

@@ -38,7 +38,7 @@ author = 'Max Kellermann'
 # built documents.
 #
 # The short X.Y version.
-version = '0.22.4'
+version = '0.22.6'
 # The full version, including alpha/beta/rc tags.
 release = version
 

doc/developer.rst

@@ -68,11 +68,11 @@ There are two active branches in the git repository:
 
 - the "unstable" branch called ``master`` where new features are
   merged.  This will become the next major release eventually.
-- the "stable" branch (currently called ``v0.21.x``) where only bug
+- the "stable" branch (currently called ``v0.22.x``) where only bug
   fixes are merged.
 
-Once :program:`MPD` 0.22 is released, a new branch called ``v0.22.x``
+Once :program:`MPD` 0.23 is released, a new branch called ``v0.23.x``
-will be created for 0.22 bug-fix releases; after that, ``v0.21.x``
+will be created for 0.23 bug-fix releases; after that, ``v0.22.x``
 will eventually cease to be maintained.
 
 After bug fixes have been added to the "stable" branch, it will be

doc/protocol.rst

@@ -677,6 +677,11 @@ Whenever possible, ids should be used.
     (directories add recursively). ``URI``
     can also be a single file.
 
+    Clients that are connected via local socket may add arbitrary
+    local files (URI is an absolute path).  Exmaple::
+
+     add "/home/foo/Music/bar.ogg"
+
 .. _command_addid:
 
 :command:`addid {URI} [POSITION]`

meson.build

@@ -1,7 +1,7 @@
 project(
   'mpd',
   ['c', 'cpp'],
-  version: '0.22.4',
+  version: '0.22.6',
   meson_version: '>= 0.49.0',
   default_options: [
     'c_std=c11',

python/build/libs.py

@@ -407,6 +407,9 @@ curl = AutotoolsProject(
         '--disable-progress-meter',
         '--disable-alt-svc',
         '--without-gnutls', '--without-nss', '--without-libssh2',
+
+        # native Windows SSL/TLS support, option ignored on non-Windows builds
+        '--with-schannel',
     ],
 
     patches='src/lib/curl/patches',

src/archive/plugins/Iso9660ArchivePlugin.cxx

@@ -221,8 +221,8 @@ public:
 		if (new_offset > size)
 			throw std::runtime_error("Invalid seek offset");
 
+		offset = new_offset;
 		skip = new_offset % ISO_BLOCKSIZE;
-		offset = new_offset - skip;
 		buffer.Clear();
 	}
 };
@@ -260,13 +260,13 @@ Iso9660InputStream::Read(std::unique_lock<Mutex> &,
 	if (r.empty()) {
 		/* the buffer is empty - read more data from the ISO file */
 
-		assert(offset % ISO_BLOCKSIZE == 0);
+		assert((offset - skip) % ISO_BLOCKSIZE == 0);
 
 		const ScopeUnlock unlock(mutex);
 
 		const lsn_t read_lsn = lsn + offset / ISO_BLOCKSIZE;
 
-		if (read_size >= ISO_BLOCKSIZE) {
+		if (read_size >= ISO_BLOCKSIZE && skip == 0) {
 			/* big read - read right into the caller's buffer */
 
 			auto nbytes = iso->SeekRead(ptr, read_lsn,

src/command/QueueCommands.cxx

@@ -326,6 +326,11 @@ CommandResult
 handle_move(Client &client, Request args, [[maybe_unused]] Response &r)
 {
 	RangeArg range = args.ParseRange(0);
+	if (range.IsOpenEnded()) {
+		r.Error(ACK_ERROR_ARG, "Open-ended range not supported");
+		return CommandResult::ERROR;
+	}
+
 	int to = args.ParseInt(1);
 	client.GetPartition().MoveRange(range.start, range.end, to);
 	return CommandResult::OK;

src/db/plugins/simple/ExportedSong.hxx

@@ -29,6 +29,12 @@
  * a #LightSong, e.g. a merged #Tag.
  */
 class ExportedSong : public LightSong {
+	/**
+	 * A reference target for LightSong::tag, but it is only used
+	 * if this instance "owns" the #Tag.  For instances referring
+	 * to a foreign #Tag instance (e.g. a Song::tag), this field
+	 * is not used (and empty).
+	 */
 	Tag tag_buffer;
 
 public:
@@ -37,6 +43,25 @@ public:
 	ExportedSong(const char *_uri, Tag &&_tag) noexcept
 		:LightSong(_uri, tag_buffer),
 		 tag_buffer(std::move(_tag)) {}
+
+	/* this custom move constructor is necessary so LightSong::tag
+	   points to this instance's #Tag field instead of leaving a
+	   dangling reference to the source object's #Tag field */
+	ExportedSong(ExportedSong &&src) noexcept
+		:LightSong(src,
+			   /* refer to tag_buffer only if the
+			      moved-from instance also owned the Tag
+			      which its LightSong::tag field refers
+			      to */
+			   OwnsTag() ? tag_buffer : src.tag),
+		 tag_buffer(std::move(src.tag_buffer)) {}
+
+	ExportedSong &operator=(ExportedSong &&) = delete;
+
+private:
+	bool OwnsTag() const noexcept {
+		return &tag == &tag_buffer;
+	}
 };
 
 #endif

src/event/BufferedSocket.cxx

@@ -36,7 +36,7 @@ BufferedSocket::DirectRead(void *data, size_t length) noexcept
 	}
 
 	const auto code = GetSocketError();
-	if (IsSocketErrorAgain(code))
+	if (IsSocketErrorReceiveWouldBlock(code))
 		return 0;
 
 	if (IsSocketErrorClosed(code))

src/event/FullyBufferedSocket.cxx

@@ -31,7 +31,7 @@ FullyBufferedSocket::DirectWrite(const void *data, size_t length) noexcept
 	const auto nbytes = GetSocket().Write((const char *)data, length);
 	if (gcc_unlikely(nbytes < 0)) {
 		const auto code = GetSocketError();
-		if (IsSocketErrorAgain(code))
+		if (IsSocketErrorSendWouldBlock(code))
 			return 0;
 
 		IdleMonitor::Cancel();

src/net/SocketError.cxx

@@ -1,20 +1,30 @@
 /*
- * Copyright 2003-2021 The Music Player Daemon Project
+ * Copyright 2015-2021 Max Kellermann <max.kellermann@gmail.com>
- * http://www.musicpd.org
  *
- * This program is free software; you can redistribute it and/or modify
+ * Redistribution and use in source and binary forms, with or without
- * it under the terms of the GNU General Public License as published by
+ * modification, are permitted provided that the following conditions
- * the Free Software Foundation; either version 2 of the License, or
+ * are met:
- * (at your option) any later version.
  *
- * This program is distributed in the hope that it will be useful,
+ * - Redistributions of source code must retain the above copyright
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * notice, this list of conditions and the following disclaimer.
- * 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
+ * - Redistributions in binary form must reproduce the above copyright
- * with this program; if not, write to the Free Software Foundation, Inc.,
+ * notice, this list of conditions and the following disclaimer in the
- * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ * documentation and/or other materials provided with the
+ * distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
+ * FOUNDATION OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+ * OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #include "SocketError.hxx"

src/net/SocketError.hxx

@@ -1,24 +1,34 @@
 /*
- * Copyright 2003-2021 The Music Player Daemon Project
+ * Copyright 2015-2021 Max Kellermann <max.kellermann@gmail.com>
- * http://www.musicpd.org
  *
- * This program is free software; you can redistribute it and/or modify
+ * Redistribution and use in source and binary forms, with or without
- * it under the terms of the GNU General Public License as published by
+ * modification, are permitted provided that the following conditions
- * the Free Software Foundation; either version 2 of the License, or
+ * are met:
- * (at your option) any later version.
  *
- * This program is distributed in the hope that it will be useful,
+ * - Redistributions of source code must retain the above copyright
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * notice, this list of conditions and the following disclaimer.
- * 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
+ * - Redistributions in binary form must reproduce the above copyright
- * with this program; if not, write to the Free Software Foundation, Inc.,
+ * notice, this list of conditions and the following disclaimer in the
- * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ * documentation and/or other materials provided with the
+ * distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
+ * FOUNDATION OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+ * OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-#ifndef MPD_SOCKET_ERROR_HXX
+#ifndef SOCKET_ERROR_HXX
-#define MPD_SOCKET_ERROR_HXX
+#define SOCKET_ERROR_HXX
 
 #include "util/Compiler.h"
 #include "system/Error.hxx"
@@ -42,14 +52,79 @@ GetSocketError() noexcept
 #endif
 }
 
-gcc_const
+constexpr bool
-static inline bool
+IsSocketErrorInProgress(socket_error_t code) noexcept
-IsSocketErrorAgain(socket_error_t code) noexcept
 {
 #ifdef _WIN32
 	return code == WSAEINPROGRESS;
 #else
-	return code == EAGAIN;
+	return code == EINPROGRESS;
+#endif
+}
+
+constexpr bool
+IsSocketErrorWouldBlock(socket_error_t code) noexcept
+{
+#ifdef _WIN32
+	return code == WSAEWOULDBLOCK;
+#else
+	return code == EWOULDBLOCK;
+#endif
+}
+
+constexpr bool
+IsSocketErrorConnectWouldBlock(socket_error_t code) noexcept
+{
+#if defined(_WIN32) || defined(__linux__)
+	/* on Windows, WSAEINPROGRESS is for blocking sockets and
+	   WSAEWOULDBLOCK for non-blocking sockets */
+	/* on Linux, EAGAIN==EWOULDBLOCK is for local sockets and
+	   EINPROGRESS is for all other sockets */
+	return IsSocketErrorInProgress(code) || IsSocketErrorWouldBlock(code);
+#else
+	/* on all other operating systems, there's just EINPROGRESS */
+	return IsSocketErrorInProgress(code);
+#endif
+}
+
+constexpr bool
+IsSocketErrorSendWouldBlock(socket_error_t code) noexcept
+{
+#ifdef _WIN32
+	/* on Windows, WSAEINPROGRESS is for blocking sockets and
+	   WSAEWOULDBLOCK for non-blocking sockets */
+	return IsSocketErrorInProgress(code) || IsSocketErrorWouldBlock(code);
+#else
+	/* on all other operating systems, there's just EAGAIN==EWOULDBLOCK */
+	return IsSocketErrorWouldBlock(code);
+#endif
+}
+
+constexpr bool
+IsSocketErrorReceiveWouldBlock(socket_error_t code) noexcept
+{
+#ifdef _WIN32
+	/* on Windows, WSAEINPROGRESS is for blocking sockets and
+	   WSAEWOULDBLOCK for non-blocking sockets */
+	return IsSocketErrorInProgress(code) || IsSocketErrorWouldBlock(code);
+#else
+	/* on all other operating systems, there's just
+	   EAGAIN==EWOULDBLOCK */
+	return IsSocketErrorWouldBlock(code);
+#endif
+}
+
+constexpr bool
+IsSocketErrorAcceptWouldBlock(socket_error_t code) noexcept
+{
+#ifdef _WIN32
+	/* on Windows, WSAEINPROGRESS is for blocking sockets and
+	   WSAEWOULDBLOCK for non-blocking sockets */
+	return IsSocketErrorInProgress(code) || IsSocketErrorWouldBlock(code);
+#else
+	/* on all other operating systems, there's just
+	   EAGAIN==EWOULDBLOCK */
+	return IsSocketErrorWouldBlock(code);
 #endif
 }
 

src/output/Control.hxx

@@ -181,6 +181,14 @@ class AudioOutputControl {
 	 */
 	bool open = false;
 
+	/**
+	 * Is the device currently playing, i.e. is its buffer
+	 * (likely) non-empty?  If not, then it will never be drained.
+	 *
+	 * This field is only valid while the output is open.
+	 */
+	bool playing;
+
 	/**
 	 * Is the device paused?  i.e. the output thread is in the
 	 * ao_pause() loop.

src/output/Thread.cxx

@@ -53,7 +53,7 @@ AudioOutputControl::InternalOpen2(const AudioFormat in_audio_format)
 	if (open && cf != output->filter_audio_format)
 		/* if the filter's output format changes, the output
 		   must be reopened as well */
-		InternalCloseOutput(true);
+		InternalCloseOutput(playing);
 
 	output->filter_audio_format = cf;
 
@@ -64,6 +64,7 @@ AudioOutputControl::InternalOpen2(const AudioFormat in_audio_format)
 		}
 
 		open = true;
+		playing = false;
 	} else if (in_audio_format != output->out_audio_format) {
 		/* reconfigure the final ConvertFilter for its new
 		   input AudioFormat */
@@ -285,6 +286,9 @@ AudioOutputControl::PlayChunk(std::unique_lock<Mutex> &lock) noexcept
 		assert(nbytes % output->out_audio_format.GetFrameSize() == 0);
 
 		source.ConsumeData(nbytes);
+
+		/* there's data to be drained from now on */
+		playing = true;
 	}
 
 	return true;
@@ -371,6 +375,9 @@ AudioOutputControl::InternalPause(std::unique_lock<Mutex> &lock) noexcept
 	}
 
 	skip_delay = true;
+
+	/* ignore drain commands until we got something new to play */
+	playing = false;
 }
 
 static void
@@ -390,6 +397,10 @@ PlayFull(FilteredAudioOutput &output, ConstBuffer<void> _buffer)
 inline void
 AudioOutputControl::InternalDrain() noexcept
 {
+	/* after this method finishes, there's nothing left to be
+	   drained */
+	playing = false;
+
 	try {
 		/* flush the filter and play its remaining output */
 
@@ -518,6 +529,7 @@ AudioOutputControl::Task() noexcept
 			source.Cancel();
 
 			if (open) {
+				playing = false;
 				const ScopeUnlock unlock(mutex);
 				output->Cancel();
 			}

src/output/plugins/PulseOutputPlugin.cxx

@@ -56,8 +56,6 @@ class PulseOutput final : AudioOutput {
 
 	size_t writable;
 
-	bool pause;
-
 	/**
 	 * Was Interrupt() called?  This will unblock Play().  It will
 	 * be reset by Cancel() and Pause(), as documented by the
@@ -113,6 +111,7 @@ public:
 
 	[[nodiscard]] std::chrono::steady_clock::duration Delay() const noexcept override;
 	size_t Play(const void *chunk, size_t size) override;
+	void Drain() override;
 	void Cancel() noexcept override;
 	bool Pause() override;
 
@@ -688,7 +687,6 @@ PulseOutput::Open(AudioFormat &audio_format)
 				     "pa_stream_connect_playback() has failed");
 	}
 
-	pause = false;
 	interrupted = false;
 }
 
@@ -699,17 +697,6 @@ PulseOutput::Close() noexcept
 
 	Pulse::LockGuard lock(mainloop);
 
-	if (pa_stream_get_state(stream) == PA_STREAM_READY) {
-		pa_operation *o =
-			pa_stream_drain(stream,
-					pulse_output_stream_success_cb, this);
-		if (o == nullptr) {
-			LogPulseError(context,
-				      "pa_stream_drain() has failed");
-		} else
-			pulse_wait_for_operation(mainloop, o);
-	}
-
 	DeleteStream();
 
 	if (context != nullptr &&
@@ -780,7 +767,7 @@ PulseOutput::Delay() const noexcept
 	Pulse::LockGuard lock(mainloop);
 
 	auto result = std::chrono::steady_clock::duration::zero();
-	if (pause && pa_stream_is_corked(stream) &&
+	if (pa_stream_is_corked(stream) &&
 	    pa_stream_get_state(stream) == PA_STREAM_READY)
 		/* idle while paused */
 		result = std::chrono::seconds(1);
@@ -796,8 +783,6 @@ PulseOutput::Play(const void *chunk, size_t size)
 
 	Pulse::LockGuard lock(mainloop);
 
-	pause = false;
-
 	/* check if the stream is (already) connected */
 
 	WaitStream();
@@ -840,6 +825,25 @@ PulseOutput::Play(const void *chunk, size_t size)
 	return size;
 }
 
+void
+PulseOutput::Drain()
+{
+	Pulse::LockGuard lock(mainloop);
+
+	if (pa_stream_get_state(stream) != PA_STREAM_READY ||
+	    pa_stream_is_suspended(stream) ||
+	    pa_stream_is_corked(stream))
+		return;
+
+	pa_operation *o =
+		pa_stream_drain(stream,
+				pulse_output_stream_success_cb, this);
+	if (o == nullptr)
+		throw MakePulseError(context, "pa_stream_drain() failed");
+
+	pulse_wait_for_operation(mainloop, o);
+}
+
 void
 PulseOutput::Cancel() noexcept
 {
@@ -876,7 +880,6 @@ PulseOutput::Pause()
 
 	Pulse::LockGuard lock(mainloop);
 
-	pause = true;
 	interrupted = false;
 
 	/* check if the stream is (already/still) connected */

src/output/plugins/WasapiOutputPlugin.cxx

@@ -24,6 +24,7 @@
 #include "mixer/MixerList.hxx"
 #include "thread/Cond.hxx"
 #include "thread/Mutex.hxx"
+#include "thread/Name.hxx"
 #include "thread/Thread.hxx"
 #include "util/AllocatedString.hxx"
 #include "util/Domain.hxx"
@@ -231,6 +232,7 @@ IAudioClient *wasapi_output_get_client(WasapiOutput &output) noexcept {
 }
 
 void WasapiOutputThread::Work() noexcept {
+	SetThreadName("Wasapi Output Worker");
 	FormatDebug(wasapi_output_domain, "Working thread started");
 	try {
 		com.emplace();

src/output/plugins/httpd/HttpdClient.cxx

@@ -278,7 +278,7 @@ HttpdClient::TryWrite() noexcept
 						      metadata_current_position);
 			if (nbytes < 0) {
 				auto e = GetSocketError();
-				if (IsSocketErrorAgain(e))
+				if (IsSocketErrorSendWouldBlock(e))
 					return true;
 
 				if (!IsSocketErrorClosed(e)) {
@@ -305,7 +305,7 @@ HttpdClient::TryWrite() noexcept
 			ssize_t nbytes = GetSocket().Write(&empty_data, 1);
 			if (nbytes < 0) {
 				auto e = GetSocketError();
-				if (IsSocketErrorAgain(e))
+				if (IsSocketErrorSendWouldBlock(e))
 					return true;
 
 				if (!IsSocketErrorClosed(e)) {
@@ -328,7 +328,7 @@ HttpdClient::TryWrite() noexcept
 				      bytes_to_write);
 		if (nbytes < 0) {
 			auto e = GetSocketError();
-			if (IsSocketErrorAgain(e))
+			if (IsSocketErrorSendWouldBlock(e))
 				return true;
 
 			if (!IsSocketErrorClosed(e)) {

src/protocol/ArgParser.cxx

@@ -94,7 +94,7 @@ ParseCommandArgRange(const char *s)
 						  s);
 
 		if (test == test2)
-			value = std::numeric_limits<int>::max();
+			return RangeArg::OpenEnded(range.start);
 
 		if (value < 0)
 			throw FormatProtocolError(ACK_ERROR_ARG,
@@ -107,9 +107,13 @@ ParseCommandArgRange(const char *s)
 
 		range.end = (unsigned)value;
 	} else {
-		range.end = (unsigned)value + 1;
+		return RangeArg::Single(range.start);
 	}
 
+	if (!range.IsWellFormed())
+		throw FormatProtocolError(ACK_ERROR_ARG,
+					  "Malformed range: %s", s);
+
 	return range;
 }
 

src/protocol/RangeArg.hxx

@@ -25,8 +25,22 @@
 struct RangeArg {
 	unsigned start, end;
 
-	static constexpr RangeArg All() {
+	/**
-		return { 0, std::numeric_limits<unsigned>::max() };
+	 * Construct an open-ended range starting at the given index.
+	 */
+	static constexpr RangeArg OpenEnded(unsigned start) noexcept {
+		return { start, std::numeric_limits<unsigned>::max() };
+	}
+
+	static constexpr RangeArg All() noexcept {
+		return OpenEnded(0);
+	}
+
+	/**
+	 * Construct an instance describing exactly one index.
+	 */
+	static constexpr RangeArg Single(unsigned i) noexcept {
+		return { i, i + 1 };
 	}
 
 	constexpr bool operator==(RangeArg other) const noexcept {
@@ -37,13 +51,45 @@ struct RangeArg {
 		return !(*this == other);
 	}
 
+	constexpr bool IsOpenEnded() const noexcept {
+		return end == All().end;
+	}
+
 	constexpr bool IsAll() const noexcept {
 		return *this == All();
 	}
 
+	constexpr bool IsWellFormed() const noexcept {
+		return start <= end;
+	}
+
+	/**
+	 * Is this range empty?  A malformed range also counts as
+	 * "empty" for this method.
+	 */
+	constexpr bool IsEmpty() const noexcept {
+		return start >= end;
+	}
+
+	/**
+	 * Check if the range contains at least this number of items.
+	 * Unlike Count(), this allows the object to be malformed.
+	 */
+	constexpr bool HasAtLeast(unsigned n) const noexcept {
+		return start + n <= end;
+	}
+
 	constexpr bool Contains(unsigned i) const noexcept {
 		return i >= start && i < end;
 	}
+
+	/**
+	 * Count the number of items covered by this range.  This requires the
+	 * object to be well-formed.
+	 */
+	constexpr unsigned Count() const noexcept {
+		return end - start;
+	}
 };
 
 #endif

src/song/LightSong.hxx

@@ -88,6 +88,19 @@ struct LightSong {
 	LightSong(const char *_uri, const Tag &_tag) noexcept
 		:uri(_uri), tag(_tag) {}
 
+	/**
+	 * A copy constructor which copies all fields, but only sets
+	 * the tag to a caller-provided reference.  This is used by
+	 * the #ExportedSong move constructor.
+	 */
+	LightSong(const LightSong &src, const Tag &_tag) noexcept
+		:directory(src.directory), uri(src.uri),
+		 real_uri(src.real_uri),
+		 tag(_tag),
+		 mtime(src.mtime),
+		 start_time(src.start_time), end_time(src.end_time),
+		 audio_format(src.audio_format) {}
+
 	gcc_pure
 	std::string GetURI() const noexcept {
 		if (directory == nullptr)

src/tag/Id3Scan.cxx

@@ -352,7 +352,7 @@ scan_id3_tag(const struct id3_tag *tag, TagHandler &handler) noexcept
 			    handler);
 	tag_id3_import_text(tag, ID3_FRAME_COMPOSER, TAG_COMPOSER,
 			    handler);
-	tag_id3_import_text(tag, "TPE3", TAG_PERFORMER,
+	tag_id3_import_text(tag, "TPE3", TAG_CONDUCTOR,
 			    handler);
 	tag_id3_import_text(tag, "TPE4", TAG_PERFORMER, handler);
 	tag_id3_import_text(tag, "TIT1", TAG_GROUPING, handler);

src/win32/ComPtr.hxx

@@ -112,6 +112,6 @@ template <typename T>
 void swap(ComPtr<T> &lhs, ComPtr<T> &rhs) noexcept {
 	lhs.swap(rhs);
 }
-}
+} // namespace std
 
 #endif

src/win32/HResult.hxx

@@ -59,6 +59,7 @@ case x:
 		C(E_INVALIDARG);
 		C(E_OUTOFMEMORY);
 		C(E_POINTER);
+		C(NO_ERROR);
 #undef C
 	}
 	return std::string_view();

test/run_input.cxx

@@ -56,6 +56,8 @@ struct CommandLine {
 
 	FromNarrowPath config_path;
 
+	std::size_t seek = 0;
+
 	std::size_t chunk_size = MAX_CHUNK_SIZE;
 
 	bool verbose = false;
@@ -67,6 +69,7 @@ enum Option {
 	OPTION_CONFIG,
 	OPTION_VERBOSE,
 	OPTION_SCAN,
+	OPTION_SEEK,
 	OPTION_CHUNK_SIZE,
 };
 
@@ -74,6 +77,7 @@ static constexpr OptionDef option_defs[] = {
 	{"config", 0, true, "Load a MPD configuration file"},
 	{"verbose", 'v', false, "Verbose logging"},
 	{"scan", 0, false, "Scan tags instead of reading raw data"},
+	{"seek", 0, true, "Start reading at this position"},
 	{"chunk-size", 0, true, "Read this number of bytes at a time"},
 };
 
@@ -108,6 +112,10 @@ ParseCommandLine(int argc, char **argv)
 			c.scan = true;
 			break;
 
+		case OPTION_SEEK:
+			c.seek = ParseSize(o.value);
+			break;
+
 		case OPTION_CHUNK_SIZE:
 			c.chunk_size = ParseSize(o.value);
 			if (c.chunk_size <= 0 || c.chunk_size > MAX_CHUNK_SIZE)
@@ -118,7 +126,7 @@ ParseCommandLine(int argc, char **argv)
 
 	auto args = option_parser.GetRemaining();
 	if (args.size != 1)
-		throw std::runtime_error("Usage: run_input [--verbose] [--config=FILE] URI");
+		throw std::runtime_error("Usage: run_input [--verbose] [--config=FILE] [--scan] [--chunk-size=BYTES] URI");
 
 	c.uri = args.front();
 	return c;
@@ -153,10 +161,14 @@ tag_save(FILE *file, const Tag &tag)
 }
 
 static int
-dump_input_stream(InputStream &is, FileDescriptor out, size_t chunk_size)
+dump_input_stream(InputStream &is, FileDescriptor out,
+		  offset_type seek, size_t chunk_size)
 {
 	std::unique_lock<Mutex> lock(is.mutex);
 
+	if (seek > 0)
+		is.Seek(lock, seek);
+
 	/* print meta data */
 
 	if (is.HasMimeType())
@@ -256,7 +268,7 @@ try {
 	Mutex mutex;
 	auto is = InputStream::OpenReady(c.uri, mutex);
 	return dump_input_stream(*is, FileDescriptor(STDOUT_FILENO),
-				 c.chunk_size);
+				 c.seek, c.chunk_size);
 } catch (...) {
 	PrintException(std::current_exception());
 	return EXIT_FAILURE;