release v0.21.2

Closes #410

NEWS

@@ -1,3 +1,17 @@
+ver 0.21.2 (2018/11/12)
+* protocol
+  - operator "=~" matches a regular expression
+  - operator "contains" matches substrings
+* decoder
+  - ffmpeg: require FFmpeg 3.1 or later
+  - ffmpeg: fix broken sound with certain codecs
+* output
+  - alsa: fix high CPU usage with dmix
+  - httpd: fix three crash bugs
+* mixer
+  - alsa: fix more rounding errors
+* fix zlib support
+
 ver 0.21.1 (2018/11/04)
 * protocol
   - allow escaping quotes in filter expressions

android/AndroidManifest.xml

@@ -2,8 +2,8 @@
 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
           package="org.musicpd"
           android:installLocation="auto"
-          android:versionCode="23"
-          android:versionName="0.21">
+          android:versionCode="24"
+          android:versionName="0.21.2">
 
   <uses-sdk android:minSdkVersion="21" android:targetSdkVersion="26"/>
 

doc/conf.py

@@ -38,7 +38,7 @@ author = 'Max Kellermann'
 # built documents.
 #
 # The short X.Y version.
-version = '0.21.1'
+version = '0.21.2'
 # The full version, including alpha/beta/rc tags.
 release = version
 

doc/protocol.rst

@@ -8,7 +8,7 @@ General protocol syntax
 Protocol overview
 =================
 
-The ``MPD`` command protocol exchanges
+The :program:`MPD` command protocol exchanges
 line-based text records between client and server over TCP.
 Once the client is connected to the server, they conduct a
 conversation until the client closes the connection. The
@@ -152,10 +152,15 @@ of:
   ``VALUE`` in ``AlbumArtist``
   and falls back to ``Artist`` tags if
   ``AlbumArtist`` does not exist.
-  ``VALUE`` is what to find.  The
-  `find` commands specify an exact value
-  and are case-sensitive; the `search`
-  commands specify a sub string and ignore case.
+  ``VALUE`` is what to find.
+
+- ``(TAG contains 'VALUE')`` checks if the given value is a substring
+  of the tag value.
+
+- ``(TAG =~ 'VALUE')`` and ``(TAG !~ 'VALUE')`` use a Perl-compatible
+  regular expression instead of doing a simple string comparison.
+  (This feature is only available if :program:`MPD` was compiled with
+  :file:`libpcre`)
 
 - ``(file == 'VALUE')``: match the full song URI
   (relative to the music directory).
@@ -184,6 +189,9 @@ of:
   be enclosed in parantheses, e.g. :code:`((artist == 'FOO') AND
   (album == 'BAR'))`
 
+The :command:`find` commands are case sensitive, which
+:command:`search` and related commands ignore case.
+
 Prior to MPD 0.21, the syntax looked like this::
 
  find TYPE VALUE
@@ -223,8 +231,7 @@ arguments for you.
 Tags
 ====
 
-The following tags are supported by
-``MPD``:
+The following tags are supported by :program:`MPD`:
 
 * **artist**: the artist name. Its meaning is not well-defined; see "*composer*" and "*performer*" for more specific tags.
 * **artistsort**: same as artist, but for sorting. This usually omits prefixes such as "The".
@@ -250,7 +257,7 @@ The following tags are supported by
 * **musicbrainz_workid**: the work id in the `MusicBrainz <https://picard.musicbrainz.org/docs/mappings/>`_ database.
 
 There can be multiple values for some of these tags.  For
-example, ``MPD`` may return multiple
+example, :program:`MPD` may return multiple
 lines with a ``performer`` tag.  A tag value is
 a UTF-8 string.
 
@@ -293,16 +300,17 @@ Recipes
 Queuing
 =======
 
-Often, users run ``MPD`` with :ref:`random <command_random>` enabled,
-but want to be able to insert songs "before" the rest of the playlist.
-That is commonly called "queuing".
+Often, users run :program:`MPD` with :ref:`random <command_random>`
+enabled, but want to be able to insert songs "before" the rest of the
+playlist.  That is commonly called "queuing".
 
-``MPD`` implements this by allowing the client to specify a "priority"
-for each song in the playlist (commands :ref:`priod <command_prio>`
-and :ref:`priodid <command_prioid>`).  A higher priority means that
-the song is going to be played before the other songs.
+:program:`MPD` implements this by allowing the client to specify a
+"priority" for each song in the playlist (commands :ref:`priod
+<command_prio>` and :ref:`priodid <command_prioid>`).  A higher
+priority means that the song is going to be played before the other
+songs.
 
-In "random" mode, ``MPD`` maintains an
+In "random" mode, :program:`MPD` maintains an
 internal randomized sequence of songs.  In this sequence,
 songs with a higher priority come first, and all songs with
 the same priority are shuffled (by default, all songs are
@@ -327,9 +335,9 @@ Command reference
    commands using song ids should be used instead of the commands
    that manipulate and control playback based on playlist
    position. Using song ids is a safer method when multiple
-   clients are interacting with ``MPD``.
+   clients are interacting with :program:`MPD`.
 
-Querying ``MPD``'s status
+Querying :program:`MPD`'s status
 ================================
 
 :command:`clearerror`
@@ -344,7 +352,7 @@ Querying ``MPD``'s status
 
 :command:`idle [SUBSYSTEMS...]` [#since_0_14]_
     Waits until there is a noteworthy change in one or more
-    of ``MPD``'s subsystems.  As soon
+    of :program:`MPD`'s subsystems.  As soon
     as there is one, it lists all changed systems in a line
     in the format ``changed:
     SUBSYSTEM``, where SUBSYSTEM is one of the
@@ -353,7 +361,7 @@ Querying ``MPD``'s status
     - ``database``: the song database has been modified after :ref:`update <command_update>`.
     - ``update``: a database update has started or finished.  If the database was modified during the update, the ``database`` event is also emitted.
     - ``stored_playlist``: a stored playlist has been modified, renamed, created or deleted
-    - ``playlist``: the current playlist has been modified
+    - ``playlist``: the queue (i.e. the current playlist) has been modified
     - ``player``: the player has been started, stopped or seeked
     - ``mixer``: the volume has been changed
     - ``output``: an audio output has been added, removed or modified (e.g. renamed, enabled or disabled)
@@ -374,11 +382,11 @@ Querying ``MPD``'s status
     to wait for events as long as mpd runs.  The
     `idle` command can be canceled by
     sending the command `noidle` (no other
-    commands are allowed). ``MPD``
+    commands are allowed). :program:`MPD`
     will then leave `idle` mode and print
     results immediately; might be empty at this time.
     If the optional ``SUBSYSTEMS`` argument
-    is used, ``MPD`` will only send
+    is used, :program:`MPD` will only send
     notifications when something changed in one of the
     specified subsytems.
 
@@ -388,7 +396,8 @@ Querying ``MPD``'s status
     Reports the current status of the player and the volume
     level.
 
-    - ``volume``: ``0-100`` or ``-1`` if the volume cannot be determined
+    - ``volume``: ``0-100`` (deprecated: ``-1`` if the volume cannot
+      be determined)
     - ``repeat``: ``0`` or ``1``
     - ``random``: ``0`` or ``1``
     - ``single`` [#since_0_15]_: ``0``, ``1``, or ``oneshot`` [#since_0_21]_
@@ -401,6 +410,7 @@ Querying ``MPD``'s status
     - ``nextsong`` [#since_0_15]_: playlist song number of the next song to be played
     - ``nextsongid`` [#since_0_15]_: playlist songid of the next song to be played
     - ``time``: total time elapsed (of current playing/paused song)
+      (deprecated, use ``elapsed`` instead)
     - ``elapsed`` [#since_0_16]_: Total time elapsed within the current song, but with higher resolution.
     - ``duration`` [#since_0_20]_: Duration of the current song in seconds.
     - ``bitrate``: instantaneous bitrate in kbps
@@ -411,6 +421,10 @@ Querying ``MPD``'s status
     - ``updating_db``: ``job id``
     - ``error``: if there is an error, returns message here
 
+    :program:`MPD` may omit lines which have no (known) value.  Older
+    :program:`MPD` versions used to have a "magic" value for
+    "unknown", e.g. ":samp:`volume: -1`".
+
 :command:`stats`
     Displays statistics.
 
@@ -524,8 +538,36 @@ Controlling playback
 :command:`stop`
     Stops playing.
 
-The current playlist
-====================
+The Queue
+=========
+
+.. note:: The "queue" used to be called "current playlist" or just
+          "playlist", but that was deemed confusing, because
+          "playlists" are also files containing a sequence of songs.
+          Those "playlist files" or "stored playlists" can be
+          :ref:`loaded into the queue <command_load>` and the queue
+          can be :ref:`saved into a playlist file <command_save>`, but
+          they are not to be confused with the queue.
+
+          Many of the command names in this section reflect the old
+          naming convention, but for the sake of compatibility, we
+          cannot rename commands.
+
+There are two ways to address songs within the queue: by their
+position and by their id.
+
+The position is a 1-based index.  It is unstable by design: if you
+move, delete or insert songs, all following indices will change, and a
+client can never be sure what song is behind a given index/position.
+
+Song ids on the other hand are stable: an id is assigned to a song
+when it is added, and will stay the same, no matter how much it is
+moved around.  Adding the same song twice will assign different ids to
+them, and a deleted-and-readded song will have a new id.  This way, a
+client can always be sure the correct song is being used.
+
+Many commands come in two flavors, one for each address type.
+Whenever possible, ids should be used.
 
 :command:`add {URI}`
     Adds the file ``URI`` to the playlist
@@ -541,7 +583,7 @@ The current playlist
      OK
 
 :command:`clear`
-    Clears the current playlist.
+    Clears the queue.
 
 .. _command_delete:
 
@@ -566,13 +608,13 @@ The current playlist
 
 :command:`playlist`
 
-    Displays the current playlist.
+    Displays the queue.
 
     Do not use this, instead use :ref:`playlistinfo
     <command_playlistinfo>`.
 
 :command:`playlistfind {TAG} {NEEDLE}`
-    Finds songs in the current playlist with strict
+    Finds songs in the queue with strict
     matching.
 
 :command:`playlistid {SONGID}`
@@ -590,7 +632,7 @@ The current playlist
 
 :command:`playlistsearch {TAG} {NEEDLE}`
     Searches case-insensitively for partial matches in the
-    current playlist.
+    queue.
 
 :command:`plchanges {VERSION} [START:END]`
     Displays changed songs currently in the playlist since
@@ -627,7 +669,7 @@ The current playlist
     but address the songs with their id.
 
 :command:`rangeid {ID} {START:END}` [#since_0_19]_
-    Since ``MPD``
+    Since :program:`MPD`
     0.19 Specifies the portion of the
     song that shall be played.  ``START`` and
     ``END`` are offsets in seconds
@@ -637,7 +679,7 @@ The current playlist
     playing cannot be manipulated this way.
 
 :command:`shuffle [START:END]`
-    Shuffles the current playlist.
+    Shuffles the queue.
     ``START:END`` is optional and specifies
     a range of songs.
 
@@ -691,6 +733,8 @@ remote playlists (absolute URI with a supported scheme).
     between clients and the server, clients should not
     compare this value with their local clock.
 
+.. _command_load:
+
 :command:`load {NAME} [START:END]`
     Loads the playlist into the current queue.  Playlist
     plugins are supported.  A range may be specified to load
@@ -721,8 +765,10 @@ remote playlists (absolute URI with a supported scheme).
     Removes the playlist `NAME.m3u` from
     the playlist directory.
 
+.. _command_save:
+
 :command:`save {NAME}`
-    Saves the current playlist to
+    Saves the queue to
     `NAME.m3u` in the playlist directory.
 
 The music database
@@ -807,7 +853,7 @@ The music database
 :command:`list {TYPE} {FILTER} [group {GROUPTYPE}]`
     Lists unique tags values of the specified type.
     ``TYPE`` can be any tag supported by
-    ``MPD`` or
+    :program:`MPD` or
     *file*.
 
     Additional arguments may specify a :ref:`filter <filter_syntax>`.
@@ -826,10 +872,10 @@ The music database
     ``URI``.
 
     Do not use this command.  Do not manage a client-side
-    copy of ``MPD``'s database.  That
+    copy of :program:`MPD`'s database.  That
     is fragile and adds huge overhead.  It will break with
     large databases.  Instead, query
-    ``MPD`` whenever you need
+    :program:`MPD` whenever you need
     something.
 
 .. _command_listallinfo:
@@ -840,16 +886,16 @@ The music database
     as :ref:`lsinfo <command_lsinfo>`
 
     Do not use this command.  Do not manage a client-side
-    copy of ``MPD``'s database.  That
+    copy of :program:`MPD`'s database.  That
     is fragile and adds huge overhead.  It will break with
     large databases.  Instead, query
-    ``MPD`` whenever you need
+    :program:`MPD` whenever you need
     something.
 
 :command:`listfiles {URI}`
     Lists the contents of the directory
     ``URI``, including files are not
-    recognized by ``MPD``.
+    recognized by :program:`MPD`.
     ``URI`` can be a path relative to the
     music directory or an URI understood by one of the
     storage plugins.  The response contains at least one
@@ -956,7 +1002,7 @@ Multiple storages can be "mounted" together, similar to the
 `mount` command on many operating
 systems, but without cooperation from the kernel.  No
 superuser privileges are necessary, beause this mapping exists
-only inside the ``MPD`` process
+only inside the :program:`MPD` process
 
 .. _command_mount:
 
@@ -999,15 +1045,15 @@ Stickers
 
 "Stickers" [#since_0_15]_ are pieces of
 information attached to existing
-``MPD`` objects (e.g. song files,
+:program:`MPD` objects (e.g. song files,
 directories, albums).  Clients can create arbitrary name/value
-pairs.  ``MPD`` itself does not assume
+pairs.  :program:`MPD` itself does not assume
 any special meaning in them.
 
 The goal is to allow clients to share additional (possibly
 dynamic) information about songs, which is neither stored on
 the client (not available to other clients), nor stored in the
-song files (``MPD`` has no write
+song files (:program:`MPD` has no write
 access).
 
 Client developers should create a standard for common sticker
@@ -1049,14 +1095,21 @@ Connection settings
 ===================
 
 :command:`close`
-    Closes the connection to ``MPD``.
-    ``MPD`` will try to send the
+    Closes the connection to :program:`MPD`.
+    :program:`MPD` will try to send the
     remaining output buffer before it actually closes the
     connection, but that cannot be guaranteed.  This command
     will not generate a response.
 
+    Clients should not use this command; instead, they should just
+    close the socket.
+
 :command:`kill`
-    Kills ``MPD``.
+    Kills :program:`MPD`.
+
+    Do not use this command.  Send ``SIGTERM`` to :program:`MPD`
+    instead, or better: let your service manager handle :program:`MPD`
+    shutdown (e.g. :command:`systemctl stop mpd`).
 
 :command:`password {PASSWORD}`
     This is used for authentication with the server.
@@ -1090,7 +1143,7 @@ Connection settings
 
 :command:`tagtypes clear`
     Clear the list of tag types this client is interested
-    in.  This means that ``MPD`` will
+    in.  This means that :program:`MPD` will
     not send any tags to this client.
 
 :command:`tagtypes all`

doc/user.rst

@@ -67,6 +67,7 @@ For example, the following installs a fairly complete list of build dependencies
 .. code-block:: none
 
     apt install g++ \
+      libpcre3-dev \
       libmad0-dev libmpg123-dev libid3tag0-dev \
       libflac-dev libvorbis-dev libopus-dev \
       libadplug-dev libaudiofile-dev libsndfile1-dev libfaad-dev \
@@ -967,7 +968,16 @@ All :program:`MPD` crashes are bugs which must be fixed by a developer, and you
 
 A crash bug report needs to contain a "backtrace".
 
-First of all, your :program:`MPD` executable must not be "stripped" (i.e. debug information deleted). The executables shipped with Linux distributions are usually stripped, but some have so-called "debug" packages (package mpd-dbg or mpd-dbgsym on Debian, mpd-debug on other distributions). Make sure this package is installed.
+First of all, your :program:`MPD` executable must not be "stripped"
+(i.e. debug information deleted).  The executables shipped with Linux
+distributions are usually stripped, but some have so-called "debug"
+packages (package :file:`mpd-dbgsym` or :file:`mpd-dbg` on Debian,
+:file:`mpd-debug` on other distributions).  Make sure this package is
+installed.
+
+If you built :program:`MPD` from sources, please recompile with Meson
+option ":code:`--buildtype=debug -Db_ndebug=false`", because this will
+add more helpful information to the backtrace.
 
 You can extract the backtrace from a core dump, or by running :program:`MPD` in a debugger, e.g.:
 
@@ -976,4 +986,5 @@ You can extract the backtrace from a core dump, or by running :program:`MPD` in
     gdb --args mpd --stdout --no-daemon --verbose
     run
 
-As soon as you have reproduced the crash, type "bt" on the gdb command prompt. Copy the output to your bug report.
+As soon as you have reproduced the crash, type ":command:`bt`" on the
+gdb command prompt. Copy the output to your bug report.

meson.build

@@ -1,7 +1,7 @@
 project(
   'mpd',
   ['c', 'cpp'],
-  version: '0.21.1',
+  version: '0.21.2',
   meson_version: '>= 0.47.2',
   default_options: [
     'c_std=c99',
@@ -315,6 +315,7 @@ subdir('src/lib/gcrypt')
 subdir('src/lib/wrap')
 subdir('src/lib/nfs')
 subdir('src/lib/oss')
+subdir('src/lib/pcre')
 subdir('src/lib/pulse')
 subdir('src/lib/sndio')
 subdir('src/lib/sqlite')

meson_options.txt

@@ -176,6 +176,7 @@ option('expat', type: 'feature', description: 'Expat XML support')
 option('icu', type: 'feature', description: 'Use libicu for Unicode')
 option('iconv', type: 'feature', description: 'Use iconv() for character set conversion')
 option('libwrap', type: 'feature', description: 'libwrap support')
+option('pcre', type: 'feature', description: 'Enable regular expression support (using libpcre)')
 option('sqlite', type: 'feature', description: 'SQLite database support (for stickers)')
 option('yajl', type: 'feature', description: 'libyajl for YAML support')
 option('zlib', type: 'feature', description: 'zlib support (for database compression)')

src/check.h

@@ -37,11 +37,4 @@
 #error config.h missing
 #endif
 
-#if defined(__linux__) && !defined(NDEBUG) && defined(ENABLE_LARGEFILE) && \
-	defined(_FEATURES_H) && defined(__i386__) && \
-	!defined(__USE_FILE_OFFSET64)
-/* on i386, check if LFS is enabled */
-#error config.h was included too late
-#endif
-
 #endif

src/decoder/plugins/FfmpegDecoderPlugin.cxx

@@ -105,45 +105,11 @@ ffmpeg_finish() noexcept
 	av_dict_free(&avformat_options);
 }
 
-#if LIBAVCODEC_VERSION_INT >= AV_VERSION_INT(57, 25, 0) /* FFmpeg 3.1 */
-
-gcc_pure
-static const AVCodecParameters &
-GetCodecParameters(const AVStream &stream) noexcept
-{
-	return *stream.codecpar;
-}
-
-gcc_pure
-static AVSampleFormat
-GetSampleFormat(const AVCodecParameters &codec_params) noexcept
-{
-	return AVSampleFormat(codec_params.format);
-}
-
-#else
-
-gcc_pure
-static const AVCodecContext &
-GetCodecParameters(const AVStream &stream) noexcept
-{
-	return *stream.codec;
-}
-
-gcc_pure
-static AVSampleFormat
-GetSampleFormat(const AVCodecContext &codec_context) noexcept
-{
-	return codec_context.sample_fmt;
-}
-
-#endif
-
 gcc_pure
 static bool
 IsAudio(const AVStream &stream) noexcept
 {
-	return GetCodecParameters(stream).codec_type == AVMEDIA_TYPE_AUDIO;
+	return stream.codecpar->codec_type == AVMEDIA_TYPE_AUDIO;
 }
 
 gcc_pure
@@ -278,8 +244,6 @@ FfmpegSendFrame(DecoderClient &client, InputStream &is,
 				 codec_context.bit_rate / 1000);
 }
 
-#if LIBAVCODEC_VERSION_INT >= AV_VERSION_INT(57, 37, 0)
-
 static DecoderCommand
 FfmpegReceiveFrames(DecoderClient &client, InputStream &is,
 		    AVCodecContext &codec_context,
@@ -324,8 +288,6 @@ FfmpegReceiveFrames(DecoderClient &client, InputStream &is,
 	}
 }
 
-#endif
-
 /**
  * Decode an #AVPacket and send the resulting PCM data to the decoder
  * API.
@@ -357,7 +319,6 @@ ffmpeg_send_packet(DecoderClient &client, InputStream &is,
 								  stream.time_base));
 	}
 
-#if LIBAVCODEC_VERSION_INT >= AV_VERSION_INT(57, 37, 0)
 	bool eof = false;
 
 	int err = avcodec_send_packet(&codec_context, &packet);
@@ -386,30 +347,6 @@ ffmpeg_send_packet(DecoderClient &client, InputStream &is,
 
 	if (eof)
 		cmd = DecoderCommand::STOP;
-#else
-	DecoderCommand cmd = DecoderCommand::NONE;
-	while (packet.size > 0 && cmd == DecoderCommand::NONE) {
-		int got_frame = 0;
-		int len = avcodec_decode_audio4(&codec_context,
-						&frame, &got_frame,
-						&packet);
-		if (len < 0) {
-			/* if error, we skip the frame */
-			LogFfmpegError(len, "decoding failed, frame skipped");
-			break;
-		}
-
-		packet.data += len;
-		packet.size -= len;
-
-		if (!got_frame || frame.nb_samples <= 0)
-			continue;
-
-		cmd = FfmpegSendFrame(client, is, codec_context,
-				      frame, skip_bytes,
-				      buffer);
-	}
-#endif
 
 	return cmd;
 }
@@ -585,11 +522,7 @@ FfmpegDecode(DecoderClient &client, InputStream &input,
 
 	AVStream &av_stream = *format_context.streams[audio_stream];
 
-#if LIBAVFORMAT_VERSION_INT < AV_VERSION_INT(57, 5, 0)
-	AVCodecContext *codec_context = av_stream.codec;
-#endif
-
-	const auto &codec_params = GetCodecParameters(av_stream);
+	const auto &codec_params = *av_stream.codecpar;
 
 	const AVCodecDescriptor *codec_descriptor =
 		avcodec_descriptor_get(codec_params.codec_id);
@@ -604,7 +537,6 @@ FfmpegDecode(DecoderClient &client, InputStream &input,
 		return;
 	}
 
-#if LIBAVFORMAT_VERSION_INT >= AV_VERSION_INT(57, 5, 0)
 	AVCodecContext *codec_context = avcodec_alloc_context3(codec);
 	if (codec_context == nullptr) {
 		LogError(ffmpeg_domain, "avcodec_alloc_context3() failed");
@@ -615,26 +547,7 @@ FfmpegDecode(DecoderClient &client, InputStream &input,
 		avcodec_free_context(&codec_context);
 	};
 
-#if LIBAVCODEC_VERSION_INT >= AV_VERSION_INT(57, 25, 0) /* FFmpeg 3.1 */
 	avcodec_parameters_to_context(codec_context, av_stream.codecpar);
-#endif
-#endif
-
-	const SampleFormat sample_format =
-		ffmpeg_sample_format(GetSampleFormat(codec_params));
-	if (sample_format == SampleFormat::UNDEFINED) {
-		// (error message already done by ffmpeg_sample_format())
-		return;
-	}
-
-	const auto audio_format = CheckAudioFormat(codec_params.sample_rate,
-						   sample_format,
-						   codec_params.channels);
-
-	/* the audio format must be read from AVCodecContext by now,
-	   because avcodec_open() has been demonstrated to fill bogus
-	   values into AVCodecContext.channels - a change that will be
-	   reverted later by avcodec_decode_audio3() */
 
 	const int open_result = avcodec_open2(codec_context, codec, nullptr);
 	if (open_result < 0) {
@@ -642,11 +555,16 @@ FfmpegDecode(DecoderClient &client, InputStream &input,
 		return;
 	}
 
-#if LIBAVFORMAT_VERSION_INT < AV_VERSION_INT(57, 5, 0)
-	AtScopeExit(codec_context) {
-		avcodec_close(codec_context);
-	};
-#endif
+	const SampleFormat sample_format =
+		ffmpeg_sample_format(codec_context->sample_fmt);
+	if (sample_format == SampleFormat::UNDEFINED) {
+		// (error message already done by ffmpeg_sample_format())
+		return;
+	}
+
+	const auto audio_format = CheckAudioFormat(codec_context->sample_rate,
+						   sample_format,
+						   codec_context->channels);
 
 	const SignedSongTime total_time =
 		av_stream.duration != (int64_t)AV_NOPTS_VALUE
@@ -697,6 +615,10 @@ FfmpegDecode(DecoderClient &client, InputStream &input,
 			/* end of file */
 			break;
 
+		AtScopeExit(&packet) {
+			av_packet_unref(&packet);
+		};
+
 		FfmpegCheckTag(client, input, format_context, audio_stream);
 
 		if (packet.size > 0 && packet.stream_index == audio_stream) {
@@ -710,12 +632,6 @@ FfmpegDecode(DecoderClient &client, InputStream &input,
 			min_frame = 0;
 		} else
 			cmd = client.GetCommand();
-
-#if LIBAVCODEC_VERSION_INT >= AV_VERSION_INT(56, 25, 100)
-		av_packet_unref(&packet);
-#else
-		av_free_packet(&packet);
-#endif
 	}
 }
 
@@ -769,10 +685,10 @@ FfmpegScanStream(AVFormatContext &format_context,
 		handler.OnDuration(FromFfmpegTime(format_context.duration,
 						  AV_TIME_BASE_Q));
 
-	const auto &codec_params = GetCodecParameters(stream);
+	const auto &codec_params = *stream.codecpar;
 	try {
 		handler.OnAudioFormat(CheckAudioFormat(codec_params.sample_rate,
-						       ffmpeg_sample_format(GetSampleFormat(codec_params)),
+						       ffmpeg_sample_format(AVSampleFormat(codec_params.format)),
 						       codec_params.channels));
 	} catch (...) {
 	}

src/event/MultiSocketMonitor.hxx

@@ -194,6 +194,19 @@ public:
 	void ReplaceSocketList(pollfd *pfds, unsigned n) noexcept;
 #endif
 
+	/**
+	 * Invoke a function for each socket which has become ready.
+	 */
+	template<typename F>
+	void ForEachReturnedEvent(F &&f) noexcept {
+		for (auto &i : fds) {
+			if (i.GetReturnedEvents() != 0) {
+				f(i.GetSocket(), i.GetReturnedEvents());
+				i.ClearReturnedEvents();
+			}
+		}
+	}
+
 protected:
 	/**
 	 * Override this method and update the socket registrations.

src/input/plugins/AlsaInputPlugin.cxx

@@ -34,7 +34,6 @@
 #include "util/Domain.hxx"
 #include "util/RuntimeError.hxx"
 #include "util/StringCompare.hxx"
-#include "util/ReusableArray.hxx"
 #include "util/ASCII.hxx"
 #include "Log.hxx"
 #include "event/MultiSocketMonitor.hxx"
@@ -69,7 +68,7 @@ class AlsaInputStream final
 	snd_pcm_t *const capture_handle;
 	const size_t frame_size;
 
-	ReusableArray<pollfd> pfd_buffer;
+	AlsaNonBlockPcm non_block;
 
 	DeferEvent defer_invalidate_sockets;
 
@@ -180,12 +179,14 @@ AlsaInputStream::PrepareSockets() noexcept
 		return std::chrono::steady_clock::duration(-1);
 	}
 
-	return PrepareAlsaPcmSockets(*this, capture_handle, pfd_buffer);
+	return non_block.PrepareSockets(*this, capture_handle);
 }
 
 void
 AlsaInputStream::DispatchSockets() noexcept
 {
+	non_block.DispatchSockets(*this, capture_handle);
+
 	const std::lock_guard<Mutex> protect(mutex);
 
 	auto w = PrepareWriteBuffer();

src/lib/alsa/NonBlock.cxx

@@ -23,8 +23,7 @@
 #include "util/RuntimeError.hxx"
 
 std::chrono::steady_clock::duration
-PrepareAlsaPcmSockets(MultiSocketMonitor &m, snd_pcm_t *pcm,
-		      ReusableArray<pollfd> &pfd_buffer)
+AlsaNonBlockPcm::PrepareSockets(MultiSocketMonitor &m, snd_pcm_t *pcm)
 {
 	int count = snd_pcm_poll_descriptors_count(pcm);
 	if (count <= 0) {
@@ -50,9 +49,32 @@ PrepareAlsaPcmSockets(MultiSocketMonitor &m, snd_pcm_t *pcm,
 	return std::chrono::steady_clock::duration(-1);
 }
 
+void
+AlsaNonBlockPcm::DispatchSockets(MultiSocketMonitor &m,
+				 snd_pcm_t *pcm) noexcept
+{
+	int count = snd_pcm_poll_descriptors_count(pcm);
+	if (count <= 0)
+		return;
+
+	const auto pfds = pfd_buffer.Get(count), end = pfds + count;
+
+	auto *i = pfds;
+	m.ForEachReturnedEvent([&i, end](SocketDescriptor s, unsigned events){
+			if (i >= end)
+				return;
+
+			i->fd = s.Get();
+			i->events = i->revents = events;
+			++i;
+		});
+
+	unsigned short dummy;
+	snd_pcm_poll_descriptors_revents(pcm, pfds, i - pfds, &dummy);
+}
+
 std::chrono::steady_clock::duration
-PrepareAlsaMixerSockets(MultiSocketMonitor &m, snd_mixer_t *mixer,
-			ReusableArray<pollfd> &pfd_buffer) noexcept
+AlsaNonBlockMixer::PrepareSockets(MultiSocketMonitor &m, snd_mixer_t *mixer) noexcept
 {
 	int count = snd_mixer_poll_descriptors_count(mixer);
 	if (count <= 0) {
@@ -69,3 +91,27 @@ PrepareAlsaMixerSockets(MultiSocketMonitor &m, snd_mixer_t *mixer,
 	m.ReplaceSocketList(pfds, count);
 	return std::chrono::steady_clock::duration(-1);
 }
+
+void
+AlsaNonBlockMixer::DispatchSockets(MultiSocketMonitor &m,
+				   snd_mixer_t *mixer) noexcept
+{
+	int count = snd_mixer_poll_descriptors_count(mixer);
+	if (count <= 0)
+		return;
+
+	const auto pfds = pfd_buffer.Get(count), end = pfds + count;
+
+	auto *i = pfds;
+	m.ForEachReturnedEvent([&i, end](SocketDescriptor s, unsigned events){
+			if (i >= end)
+				return;
+
+			i->fd = s.Get();
+			i->events = i->revents = events;
+			++i;
+		});
+
+	unsigned short dummy;
+	snd_mixer_poll_descriptors_revents(mixer, pfds, i - pfds, &dummy);
+}

src/lib/alsa/NonBlock.hxx

@@ -30,23 +30,42 @@
 class MultiSocketMonitor;
 
 /**
- * Update #MultiSocketMonitor's socket list from
- * snd_pcm_poll_descriptors().  To be called from
- * MultiSocketMonitor::PrepareSockets().
- *
- * Throws exception on error.
+ * Helper class for #MultiSocketMonitor's virtual methods which
+ * manages the file descriptors for a #snd_pcm_t.
  */
-std::chrono::steady_clock::duration
-PrepareAlsaPcmSockets(MultiSocketMonitor &m, snd_pcm_t *pcm,
-		      ReusableArray<pollfd> &pfd_buffer);
+class AlsaNonBlockPcm {
+	ReusableArray<pollfd> pfd_buffer;
+
+public:
+	/**
+	 * Throws on error.
+	 */
+	std::chrono::steady_clock::duration PrepareSockets(MultiSocketMonitor &m,
+							   snd_pcm_t *pcm);
+
+	/**
+	 * Wrapper for snd_pcm_poll_descriptors_revents(), to be
+	 * called from MultiSocketMonitor::DispatchSockets().
+	 */
+	void DispatchSockets(MultiSocketMonitor &m, snd_pcm_t *pcm) noexcept;
+};
 
 /**
- * Update #MultiSocketMonitor's socket list from
- * snd_mixer_poll_descriptors().  To be called from
- * MultiSocketMonitor::PrepareSockets().
+ * Helper class for #MultiSocketMonitor's virtual methods which
+ * manages the file descriptors for a #snd_mixer_t.
  */
-std::chrono::steady_clock::duration
-PrepareAlsaMixerSockets(MultiSocketMonitor &m, snd_mixer_t *mixer,
-		      ReusableArray<pollfd> &pfd_buffer) noexcept;
+class AlsaNonBlockMixer {
+	ReusableArray<pollfd> pfd_buffer;
+
+public:
+	std::chrono::steady_clock::duration PrepareSockets(MultiSocketMonitor &m,
+							   snd_mixer_t *mixer) noexcept;
+
+	/**
+	 * Wrapper for snd_mixer_poll_descriptors_revents(), to be
+	 * called from MultiSocketMonitor::DispatchSockets().
+	 */
+	void DispatchSockets(MultiSocketMonitor &m, snd_mixer_t *mixer) noexcept;
+};
 
 #endif

src/lib/ffmpeg/meson.build

@@ -1,6 +1,6 @@
-libavformat_dep = dependency('libavformat', version: '>= 56.1', required: get_option('ffmpeg'))
-libavcodec_dep = dependency('libavcodec', version: '>= 56.1', required: get_option('ffmpeg'))
-libavutil_dep = dependency('libavutil', version: '>= 54.3', required: get_option('ffmpeg'))
+libavformat_dep = dependency('libavformat', version: '>= 57.40', required: get_option('ffmpeg'))
+libavcodec_dep = dependency('libavcodec', version: '>= 57.48', required: get_option('ffmpeg'))
+libavutil_dep = dependency('libavutil', version: '>= 55.27', required: get_option('ffmpeg'))
 
 enable_ffmpeg = libavformat_dep.found() and libavcodec_dep.found() and libavutil_dep.found()
 conf.set('ENABLE_FFMPEG', enable_ffmpeg)

src/lib/pcre/RegexPointer.hxx

@@ -0,0 +1,66 @@
+/*
+ * Copyright 2007-2018 Content Management AG
+ * All rights reserved.
+ *
+ * author: Max Kellermann <mk@cm4all.com>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * - Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *
+ * - Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * 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 REGEX_POINTER_HXX
+#define REGEX_POINTER_HXX
+
+#include "util/StringView.hxx"
+#include "util/Compiler.h"
+
+#include <pcre.h>
+
+#include <array>
+
+class RegexPointer {
+protected:
+	pcre *re = nullptr;
+	pcre_extra *extra = nullptr;
+
+	unsigned n_capture = 0;
+
+public:
+	constexpr bool IsDefined() const noexcept {
+		return re != nullptr;
+	}
+
+	gcc_pure
+	bool Match(StringView s) const noexcept {
+		/* we don't need the data written to ovector, but PCRE can
+		   omit internal allocations if we pass a buffer to
+		   pcre_exec() */
+		std::array<int, 16> ovector;
+		return pcre_exec(re, extra, s.data, s.size,
+				 0, 0, &ovector.front(), ovector.size()) >= 0;
+	}
+};
+
+#endif

src/lib/pcre/UniqueRegex.cxx

@@ -0,0 +1,71 @@
+/*
+ * Copyright 2007-2018 Content Management AG
+ * All rights reserved.
+ *
+ * author: Max Kellermann <mk@cm4all.com>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * - Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *
+ * - Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * 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 "UniqueRegex.hxx"
+#include "util/RuntimeError.hxx"
+
+void
+UniqueRegex::Compile(const char *pattern, bool anchored, bool capture,
+		     bool caseless)
+{
+	constexpr int default_options = PCRE_DOTALL|PCRE_NO_AUTO_CAPTURE|PCRE_UTF8;
+
+	int options = default_options;
+	if (anchored)
+		options |= PCRE_ANCHORED;
+	if (capture)
+		options &= ~PCRE_NO_AUTO_CAPTURE;
+	if (caseless)
+		options |= PCRE_CASELESS;
+
+	const char *error_string;
+	int error_offset;
+	re = pcre_compile(pattern, options, &error_string, &error_offset, nullptr);
+	if (re == nullptr)
+		throw FormatRuntimeError("Error in regex at offset %d: %s",
+					 error_offset, error_string);
+
+	int study_options = 0;
+#ifdef PCRE_CONFIG_JIT
+	study_options |= PCRE_STUDY_JIT_COMPILE;
+#endif
+	extra = pcre_study(re, study_options, &error_string);
+	if (extra == nullptr && error_string != nullptr) {
+		pcre_free(re);
+		re = nullptr;
+		throw FormatRuntimeError("Regex study error: %s", error_string);
+	}
+
+	int n;
+	if (capture && pcre_fullinfo(re, extra, PCRE_INFO_CAPTURECOUNT, &n) == 0)
+		n_capture = n;
+}

src/lib/pcre/UniqueRegex.hxx

@@ -0,0 +1,79 @@
+/*
+ * Copyright 2007-2018 Content Management AG
+ * All rights reserved.
+ *
+ * author: Max Kellermann <mk@cm4all.com>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * - Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *
+ * - Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * 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 UNIQUE_REGEX_HXX
+#define UNIQUE_REGEX_HXX
+
+#include "RegexPointer.hxx"
+#include "util/StringView.hxx"
+
+#include <algorithm>
+
+#include <pcre.h>
+
+class UniqueRegex : public RegexPointer {
+public:
+	UniqueRegex() = default;
+
+	UniqueRegex(const char *pattern, bool anchored, bool capture,
+		    bool caseless) {
+		Compile(pattern, anchored, capture, caseless);
+	}
+
+	UniqueRegex(UniqueRegex &&src) noexcept:RegexPointer(src) {
+		src.re = nullptr;
+		src.extra = nullptr;
+	}
+
+	~UniqueRegex() noexcept {
+		pcre_free(re);
+#ifdef PCRE_CONFIG_JIT
+		pcre_free_study(extra);
+#else
+		pcre_free(extra);
+#endif
+	}
+
+	UniqueRegex &operator=(UniqueRegex &&src) {
+		using std::swap;
+		swap<RegexPointer>(*this, src);
+		return *this;
+	}
+
+	/**
+	 * Throws std::runtime_error on error.
+	 */
+	void Compile(const char *pattern, bool anchored, bool capture,
+		     bool caseless);
+};
+
+#endif

src/lib/pcre/meson.build

@@ -0,0 +1,21 @@
+pcre_dep = dependency('libpcre', required: get_option('pcre'))
+conf.set('HAVE_PCRE', pcre_dep.found())
+if not pcre_dep.found()
+  subdir_done()
+endif
+
+pcre = static_library(
+  'pcre',
+  'UniqueRegex.cxx',
+  include_directories: inc,
+  dependencies: [
+    pcre_dep,
+  ],
+)
+
+pcre_dep = declare_dependency(
+  link_with: pcre,
+  dependencies: [
+    pcre_dep,
+  ],
+)

src/lib/zlib/meson.build

@@ -1,4 +1,5 @@
 zlib_dep = dependency('zlib', required: get_option('zlib'))
+conf.set('ENABLE_ZLIB', zlib_dep.found())
 if not zlib_dep.found()
   subdir_done()
 endif
@@ -14,4 +15,7 @@ zlib = static_library(
 
 zlib_dep = declare_dependency(
   link_with: zlib,
+  dependencies: [
+    zlib_dep,
+  ],
 )

src/mixer/plugins/AlsaMixerPlugin.cxx

@@ -26,7 +26,6 @@
 #include "event/DeferEvent.hxx"
 #include "event/Call.hxx"
 #include "util/ASCII.hxx"
-#include "util/ReusableArray.hxx"
 #include "util/Domain.hxx"
 #include "util/RuntimeError.hxx"
 #include "Log.hxx"
@@ -48,7 +47,7 @@ class AlsaMixerMonitor final : MultiSocketMonitor {
 
 	snd_mixer_t *mixer;
 
-	ReusableArray<pollfd> pfd_buffer;
+	AlsaNonBlockMixer non_block;
 
 public:
 	AlsaMixerMonitor(EventLoop &_loop, snd_mixer_t *_mixer)
@@ -110,7 +109,7 @@ AlsaMixerMonitor::PrepareSockets() noexcept
 		return std::chrono::steady_clock::duration(-1);
 	}
 
-	return PrepareAlsaMixerSockets(*this, mixer, pfd_buffer);
+	return non_block.PrepareSockets(*this, mixer);
 }
 
 void
@@ -118,6 +117,8 @@ AlsaMixerMonitor::DispatchSockets() noexcept
 {
 	assert(mixer != nullptr);
 
+	non_block.DispatchSockets(*this, mixer);
+
 	int err = snd_mixer_handle_events(mixer);
 	if (err < 0) {
 		FormatError(alsa_mixer_domain,

src/mixer/plugins/volume_mapping.c

@@ -135,6 +135,13 @@ static int set_normalized_volume(snd_mixer_elem_t *elem,
 		if (err < 0)
 			return err;
 
+		/* two special cases to avoid rounding errors at 0% and
+		   100% */
+		if (volume <= 0)
+			return set_raw[ctl_dir](elem, min);
+		else if (volume >= 1)
+			return set_raw[ctl_dir](elem, max);
+
 		value = lrint_dir(volume * (max - min), dir) + min;
 		return set_raw[ctl_dir](elem, value);
 	}
@@ -143,7 +150,7 @@ static int set_normalized_volume(snd_mixer_elem_t *elem,
 	   100% */
 	if (volume <= 0)
 		return set_dB[ctl_dir](elem, min, dir);
-	else if (volume >= 100)
+	else if (volume >= 1)
 		return set_dB[ctl_dir](elem, max, dir);
 
 	if (use_linear_dB_scale(min, max)) {

src/output/Control.cxx

@@ -347,10 +347,22 @@ AudioOutputControl::LockAllowPlay() noexcept
 void
 AudioOutputControl::LockRelease() noexcept
 {
-	if (always_on)
-		LockPauseAsync();
+	if (output->mixer != nullptr &&
+	    (!always_on || !output->SupportsPause()))
+		/* the device has no pause mode: close the mixer,
+		   unless its "global" flag is set (checked by
+		   mixer_auto_close()) */
+		mixer_auto_close(output->mixer);
+
+	const std::lock_guard<Mutex> protect(mutex);
+
+	assert(!open || !fail_timer.IsDefined());
+	assert(allow_play);
+
+	if (IsOpen())
+		CommandWait(Command::RELEASE);
 	else
-		LockCloseWait();
+		fail_timer.Reset();
 }
 
 void

src/output/Control.hxx

@@ -131,6 +131,12 @@ class AudioOutputControl {
 		CLOSE,
 		PAUSE,
 
+		/**
+		 * Close or pause the device, depending on the
+		 * #always_on setting.
+		 */
+		RELEASE,
+
 		/**
 		 * Drains the internal (hardware) buffers of the device.  This
 		 * operation may take a while to complete.

src/output/Filtered.cxx

@@ -124,9 +124,14 @@ FilteredAudioOutput::OpenOutputAndConvert(AudioFormat desired_audio_format)
 void
 FilteredAudioOutput::CloseOutput(bool drain) noexcept
 {
-	if (drain)
-		Drain();
-	else
+	if (drain) {
+		try {
+			Drain();
+		} catch (...) {
+			FormatError(std::current_exception(),
+				    "Failed to drain %s", GetLogName());
+		}
+	} else
 		Cancel();
 
 	output->Close();

src/output/Interface.hxx

@@ -159,6 +159,8 @@ public:
 
 	/**
 	 * Wait until the device has finished playing.
+	 *
+	 * Throws on error.
 	 */
 	virtual void Drain() {}
 

src/output/Source.cxx

@@ -41,8 +41,10 @@ AudioOutputSource::Open(const AudioFormat audio_format, const MusicPipe &_pipe,
 {
 	assert(audio_format.IsValid());
 
-	if (!IsOpen() || &_pipe != &pipe.GetPipe())
+	if (!IsOpen() || &_pipe != &pipe.GetPipe()) {
+		current_chunk = nullptr;
 		pipe.Init(_pipe);
+	}
 
 	/* (re)open the filter */
 

src/output/Thread.cxx

@@ -443,8 +443,7 @@ AudioOutputControl::Task() noexcept
 		case Command::PAUSE:
 			if (!open) {
 				/* the output has failed after
-				   audio_output_all_pause() has
-				   submitted the PAUSE command; bail
+				   the PAUSE command was submitted; bail
 				   out */
 				CommandFinished();
 				break;
@@ -457,6 +456,35 @@ AudioOutputControl::Task() noexcept
 			   the new command first */
 			continue;
 
+		case Command::RELEASE:
+			if (!open) {
+				/* the output has failed after
+				   the PAUSE command was submitted; bail
+				   out */
+				CommandFinished();
+				break;
+			}
+
+			if (always_on) {
+				/* in "always_on" mode, the output is
+				   paused instead of being closed;
+				   however we need to flush the
+				   AudioOutputSource because its data
+				   have been invalidated by stopping
+				   the actual playback */
+				source.Cancel();
+				InternalPause();
+			} else {
+				InternalClose(false);
+				CommandFinished();
+			}
+
+			/* don't "break" here: this might cause
+			   Play() to be called when command==CLOSE
+			   ends the paused state - "continue" checks
+			   the new command first */
+			continue;
+
 		case Command::DRAIN:
 			if (open)
 				InternalDrain();

src/output/plugins/AlsaOutputPlugin.cxx

@@ -148,10 +148,7 @@ class AlsaOutput final
 	 */
 	uint8_t *silence;
 
-	/**
-	 * For PrepareAlsaPcmSockets().
-	 */
-	ReusableArray<pollfd> pfd_buffer;
+	AlsaNonBlockPcm non_block;
 
 	/**
 	 * For copying data from OutputThread to IOThread.
@@ -881,7 +878,7 @@ AlsaOutput::PrepareSockets() noexcept
 	}
 
 	try {
-		return PrepareAlsaPcmSockets(*this, pcm, pfd_buffer);
+		return non_block.PrepareSockets(*this, pcm);
 	} catch (...) {
 		ClearSocketList();
 		LockCaughtError();
@@ -892,6 +889,8 @@ AlsaOutput::PrepareSockets() noexcept
 void
 AlsaOutput::DispatchSockets() noexcept
 try {
+	non_block.DispatchSockets(*this, pcm);
+
 	{
 		const std::lock_guard<Mutex> lock(mutex);
 

src/output/plugins/httpd/HttpdClient.hxx

@@ -98,8 +98,11 @@ class HttpdClient final
 
 	/**
 	 * If the current metadata was already sent to the client.
+	 *
+	 * Initialized to `true` because there is no metadata #Page
+	 * pending to be sent.
 	 */
-	bool metadata_sent = false;
+	bool metadata_sent = true;
 
 	/**
 	 * The amount of streaming data between each metadata block

src/player/Thread.cxx

@@ -23,7 +23,8 @@
  * between the decoder thread and the output thread(s): it receives
  * #MusicChunk objects from the decoder, optionally mixes them
  * (cross-fading), applies software volume, and sends them to the
- * audio outputs via audio_output_all_play().
+ * audio outputs via PlayerOutputs::Play()
+ * (i.e. MultipleOutputs::Play()).
  *
  * It is controlled by the main thread (the playlist code), see
  * Control.hxx.  The playlist enqueues new songs into the player
@@ -970,6 +971,15 @@ Player::Run() noexcept
 	pc.CommandFinished();
 
 	while (ProcessCommand()) {
+		if (decoder_starting) {
+			/* wait until the decoder is initialized completely */
+
+			if (!CheckDecoderStartup())
+				break;
+
+			continue;
+		}
+
 		if (buffering) {
 			/* buffering at the start of the song - wait
 			   until the buffer is large enough, to
@@ -987,15 +997,6 @@ Player::Run() noexcept
 			}
 		}
 
-		if (decoder_starting) {
-			/* wait until the decoder is initialized completely */
-
-			if (!CheckDecoderStartup())
-				break;
-
-			continue;
-		}
-
 		if (dc.IsIdle() && queued && dc.pipe == pipe) {
 			/* the decoder has finished the current song;
 			   make it decode the next song */

src/song/Filter.cxx

@@ -93,9 +93,8 @@ SongFilter::SongFilter(TagType tag, const char *value, bool fold_case)
 {
 	/* for compatibility with MPD 0.20 and older, "fold_case" also
 	   switches on "substring" */
-	and_filter.AddItem(std::make_unique<TagSongFilter>(tag, value,
-							   fold_case, fold_case,
-							   false));
+	and_filter.AddItem(std::make_unique<TagSongFilter>(tag,
+							   StringFilter(value, fold_case, fold_case, false)));
 }
 
 SongFilter::~SongFilter()
@@ -198,6 +197,56 @@ ExpectQuoted(const char *&s)
 	return {buffer, length};
 }
 
+/**
+ * Parse a string operator and its second operand and convert it to a
+ * #StringFilter.
+ *
+ * Throws on error.
+ */
+static StringFilter
+ParseStringFilter(const char *&s, bool fold_case)
+{
+	if (auto after_contains = StringAfterPrefixIgnoreCase(s, "contains ")) {
+		s = StripLeft(after_contains);
+		auto value = ExpectQuoted(s);
+		return StringFilter(std::move(value),
+				    fold_case, true, false);
+	}
+
+	if (auto after_not_contains = StringAfterPrefixIgnoreCase(s, "!contains ")) {
+		s = StripLeft(after_not_contains);
+		auto value = ExpectQuoted(s);
+		return StringFilter(std::move(value),
+				    fold_case, true, true);
+	}
+
+	bool negated = false;
+
+#ifdef HAVE_PCRE
+	if ((s[0] == '!' || s[0] == '=') && s[1] == '~') {
+		negated = s[0] == '!';
+		s = StripLeft(s + 2);
+		auto value = ExpectQuoted(s);
+		StringFilter f(std::move(value), fold_case, false, negated);
+		f.SetRegex(std::make_shared<UniqueRegex>(f.GetValue().c_str(),
+							 false, false,
+							 fold_case));
+		return f;
+	}
+#endif
+
+	if (s[0] == '!' && s[1] == '=')
+		negated = true;
+	else if (s[0] != '=' || s[1] != '=')
+		throw std::runtime_error("'==' or '!=' expected");
+
+	s = StripLeft(s + 2);
+	auto value = ExpectQuoted(s);
+
+	return StringFilter(std::move(value),
+			    fold_case, false, negated);
+}
+
 ISongFilterPtr
 SongFilter::ParseExpression(const char *&s, bool fold_case)
 {
@@ -280,14 +329,7 @@ SongFilter::ParseExpression(const char *&s, bool fold_case)
 
 		return std::make_unique<AudioFormatSongFilter>(value);
 	} else {
-		bool negated = false;
-		if (s[0] == '!' && s[1] == '=')
-			negated = true;
-		else if (s[0] != '=' || s[1] != '=')
-			throw std::runtime_error("'==' or '!=' expected");
-
-		s = StripLeft(s + 2);
-		auto value = ExpectQuoted(s);
+		auto string_filter = ParseStringFilter(s, fold_case);
 		if (*s != ')')
 			throw std::runtime_error("')' expected");
 
@@ -297,15 +339,10 @@ SongFilter::ParseExpression(const char *&s, bool fold_case)
 			type = TAG_NUM_OF_ITEM_TYPES;
 
 		if (type == LOCATE_TAG_FILE_TYPE)
-			return std::make_unique<UriSongFilter>(std::move(value),
-							       fold_case,
-							       false,
-							       negated);
+			return std::make_unique<UriSongFilter>(std::move(string_filter));
 
 		return std::make_unique<TagSongFilter>(TagType(type),
-						       std::move(value),
-						       fold_case, false,
-						       negated);
+						       std::move(string_filter));
 	}
 }
 
@@ -332,10 +369,10 @@ SongFilter::Parse(const char *tag_string, const char *value, bool fold_case)
 	case LOCATE_TAG_FILE_TYPE:
 		/* for compatibility with MPD 0.20 and older,
 		   "fold_case" also switches on "substring" */
-		and_filter.AddItem(std::make_unique<UriSongFilter>(value,
-								   fold_case,
-								   fold_case,
-								   false));
+		and_filter.AddItem(std::make_unique<UriSongFilter>(StringFilter(value,
+										fold_case,
+										fold_case,
+										false)));
 		break;
 
 	default:
@@ -345,10 +382,10 @@ SongFilter::Parse(const char *tag_string, const char *value, bool fold_case)
 		/* for compatibility with MPD 0.20 and older,
 		   "fold_case" also switches on "substring" */
 		and_filter.AddItem(std::make_unique<TagSongFilter>(TagType(tag),
-								   value,
-								   fold_case,
-								   fold_case,
-								   false));
+								   StringFilter(value,
+										fold_case,
+										fold_case,
+										false)));
 		break;
 	}
 }

src/song/OptimizeFilter.cxx

@@ -58,11 +58,11 @@ OptimizeSongFilter(ISongFilterPtr f) noexcept
 			/* #TagSongFilter has its own "negated" flag,
 			   so we can drop the #NotSongFilter
 			   container */
-			tf->negated = !tf->negated;
+			tf->ToggleNegated();
 			return child;
 		} else if (auto *uf = dynamic_cast<UriSongFilter *>(child.get())) {
 			/* same for #UriSongFilter */
-			uf->negated = !uf->negated;
+			uf->ToggleNegated();
 			return child;
 		}
 

src/song/StringFilter.cxx

@@ -23,14 +23,19 @@
 
 #include <assert.h>
 
-bool
-StringFilter::Match(const char *s) const noexcept
+inline bool
+StringFilter::MatchWithoutNegation(const char *s) const noexcept
 {
 #if !CLANG_CHECK_VERSION(3,6)
 	/* disabled on clang due to -Wtautological-pointer-compare */
 	assert(s != nullptr);
 #endif
 
+#ifdef HAVE_PCRE
+	if (regex)
+		return regex->Match(s);
+#endif
+
 	if (fold_case) {
 		return substring
 			? fold_case.IsIn(s)
@@ -41,3 +46,9 @@ StringFilter::Match(const char *s) const noexcept
 			: value == s;
 	}
 }
+
+bool
+StringFilter::Match(const char *s) const noexcept
+{
+	return MatchWithoutNegation(s) != negated;
+}

src/song/StringFilter.hxx

@@ -23,7 +23,12 @@
 #include "lib/icu/Compare.hxx"
 #include "util/Compiler.h"
 
+#ifdef HAVE_PCRE
+#include "lib/pcre/UniqueRegex.hxx"
+#endif
+
 #include <string>
+#include <memory>
 
 class StringFilter {
 	std::string value;
@@ -33,24 +38,45 @@ class StringFilter {
 	 */
 	IcuCompare fold_case;
 
+#ifdef HAVE_PCRE
+	std::shared_ptr<UniqueRegex> regex;
+#endif
+
 	/**
 	 * Search for substrings instead of matching the whole string?
 	 */
 	bool substring;
 
+	bool negated;
+
 public:
 	template<typename V>
-	StringFilter(V &&_value, bool _fold_case, bool _substring)
+	StringFilter(V &&_value, bool _fold_case, bool _substring, bool _negated)
 		:value(std::forward<V>(_value)),
 		 fold_case(_fold_case
 			   ? IcuCompare(value.c_str())
 			   : IcuCompare()),
-		 substring(_substring) {}
+		 substring(_substring), negated(_negated) {}
 
 	bool empty() const noexcept {
 		return value.empty();
 	}
 
+	bool IsRegex() const noexcept {
+#ifdef HAVE_PCRE
+		return !!regex;
+#else
+		return false;
+#endif
+	}
+
+#ifdef HAVE_PCRE
+	template<typename R>
+	void SetRegex(R &&_regex) noexcept {
+		regex = std::forward<R>(_regex);
+	}
+#endif
+
 	const auto &GetValue() const noexcept {
 		return value;
 	}
@@ -59,8 +85,28 @@ public:
 		return fold_case;
 	}
 
+	bool IsNegated() const noexcept {
+		return negated;
+	}
+
+	void ToggleNegated() noexcept {
+		negated = !negated;
+	}
+
+	const char *GetOperator() const noexcept {
+		return IsRegex()
+			? (negated ? "!~" : "=~")
+			: (substring
+			   ? (negated ? "!contains" : "contains")
+			   : (negated ? "!=" : "=="));
+	}
+
 	gcc_pure
 	bool Match(const char *s) const noexcept;
+
+private:
+	gcc_pure
+	bool MatchWithoutNegation(const char *s) const noexcept;
 };
 
 #endif

src/song/TagSongFilter.cxx

@@ -31,7 +31,8 @@ TagSongFilter::ToExpression() const noexcept
 		? "any"
 		: tag_item_names[type];
 
-	return std::string("(") + name + " " + (negated ? "!=" : "==") + " \"" + EscapeFilterString(filter.GetValue()) + "\")";
+	return std::string("(") + name + " " + filter.GetOperator()
+		+ " \"" + EscapeFilterString(filter.GetValue()) + "\")";
 }
 
 bool
@@ -89,5 +90,5 @@ TagSongFilter::MatchNN(const Tag &tag) const noexcept
 bool
 TagSongFilter::Match(const LightSong &song) const noexcept
 {
-	return MatchNN(song.tag) != negated;
+	return MatchNN(song.tag);
 }

src/song/TagSongFilter.hxx

@@ -34,18 +34,11 @@ struct LightSong;
 class TagSongFilter final : public ISongFilter {
 	TagType type;
 
-	bool negated;
-
 	StringFilter filter;
 
-	friend ISongFilterPtr OptimizeSongFilter(ISongFilterPtr) noexcept;
-
 public:
-	template<typename V>
-	TagSongFilter(TagType _type, V &&_value, bool fold_case, bool substring,
-		      bool _negated)
-		:type(_type), negated(_negated),
-		 filter(std::forward<V>(_value), fold_case, substring) {}
+	TagSongFilter(TagType _type, StringFilter &&_filter) noexcept
+		:type(_type), filter(std::move(_filter)) {}
 
 	TagType GetTagType() const {
 		return type;
@@ -60,7 +53,11 @@ public:
 	}
 
 	bool IsNegated() const noexcept {
-		return negated;
+		return filter.IsNegated();
+	}
+
+	void ToggleNegated() noexcept {
+		filter.ToggleNegated();
 	}
 
 	ISongFilterPtr Clone() const noexcept override {

src/song/UriSongFilter.cxx

@@ -25,11 +25,12 @@
 std::string
 UriSongFilter::ToExpression() const noexcept
 {
-	return std::string("(file ") + (negated ? "!=" : "==") + " \"" + EscapeFilterString(filter.GetValue()) + "\")";
+	return std::string("(file ") + filter.GetOperator()
+		+ " \"" + EscapeFilterString(filter.GetValue()) + "\")";
 }
 
 bool
 UriSongFilter::Match(const LightSong &song) const noexcept
 {
-	return filter.Match(song.GetURI().c_str()) != negated;
+	return filter.Match(song.GetURI().c_str());
 }

src/song/UriSongFilter.hxx

@@ -26,16 +26,9 @@
 class UriSongFilter final : public ISongFilter {
 	StringFilter filter;
 
-	bool negated;
-
-	friend ISongFilterPtr OptimizeSongFilter(ISongFilterPtr) noexcept;
-
 public:
-	template<typename V>
-	UriSongFilter(V &&_value, bool fold_case, bool substring,
-		      bool _negated)
-		:filter(std::forward<V>(_value), fold_case, substring),
-		 negated(_negated) {}
+	UriSongFilter(StringFilter &&_filter) noexcept
+		:filter(std::move(_filter)) {}
 
 	const auto &GetValue() const noexcept {
 		return filter.GetValue();
@@ -46,7 +39,11 @@ public:
 	}
 
 	bool IsNegated() const noexcept {
-		return negated;
+		return filter.IsNegated();
+	}
+
+	void ToggleNegated() noexcept {
+		filter.ToggleNegated();
 	}
 
 	ISongFilterPtr Clone() const noexcept override {

src/song/meson.build

@@ -19,6 +19,7 @@ song_dep = declare_dependency(
   link_with: song,
   dependencies: [
     icu_dep,
+    pcre_dep,
     tag_dep,
     util_dep,
   ],