release v0.21.9

Closes https://github.com/MusicPlayerDaemon/MPD/issues/340

.travis.yml

@@ -9,7 +9,7 @@ matrix:
           sources:
             - ubuntu-toolchain-r-test
             - sourceline: 'ppa:mhier/libboost-latest'
-            - sourceline: 'ppa:saiarcot895/chromium-dev' # for ninja-build
+            - sourceline: 'ppa:mstipicevic/ninja-build-1-7-2'
             - sourceline: 'ppa:deadsnakes/ppa' # for Python 3.7 (required by Meson)
           packages:
             - g++-6
@@ -34,7 +34,7 @@ matrix:
           sources:
             - ubuntu-toolchain-r-test
             - sourceline: 'ppa:mhier/libboost-latest'
-            - sourceline: 'ppa:saiarcot895/chromium-dev' # for ninja-build
+            - sourceline: 'ppa:mstipicevic/ninja-build-1-7-2'
             - sourceline: 'ppa:deadsnakes/ppa' # for Python 3.7 (required by Meson)
           packages:
             - g++-8

NEWS

@@ -1,3 +1,25 @@
+ver 0.21.9 (2019/05/20)
+* input
+  - buffer: fix deadlock bug
+* Android
+  - fix crash on ARMv7
+  - request storage permission on Android 6+
+* fix spurious "single" mode bug
+
+ver 0.21.8 (2019/04/23)
+* input
+  - smbclient: download to buffer instead of throttling transfer
+* output
+  - httpd: add missing mutex lock
+  - httpd: fix use-after-free bug
+* playlist
+  - soundcloud: fix "Unsupported URI scheme" (0.21.6 regression)
+* fix Bonjour bug
+* fix build failure with GCC 9
+* fix build failure with -Ddatabase=false
+* systemd: add user socket unit
+* doc: "list file" is deprecated
+
 ver 0.21.7 (2019/04/03)
 * input
   - qobuz/tidal: scan tags when loading a playlist

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="29"
-          android:versionName="0.21.7">
+          android:versionCode="32"
+          android:versionName="0.21.9">
 
   <uses-sdk android:minSdkVersion="21" android:targetSdkVersion="26"/>
 

android/build.py

@@ -138,6 +138,12 @@ class AndroidNdkToolchain:
         libstdcxx_ldflags = libstdcxx_flags + ' -L' + libcxx_libs_path
         libstdcxx_libs = '-lc++_static -lc++abi'
 
+        if self.is_armv7:
+            # On 32 bit ARM, clang generates no ".eh_frame" section;
+            # instead, the LLVM unwinder library is used for unwinding
+            # the stack after a C++ exception was thrown
+            libstdcxx_libs += ' -lunwind'
+
         if use_cxx:
             self.cxxflags += ' ' + libstdcxx_cxxflags
             self.ldflags += ' ' + libstdcxx_ldflags

android/meson.build

@@ -6,7 +6,7 @@ android_sdk = get_option('android_sdk')
 android_abi = get_option('android_abi')
 
 android_sdk_build_tools_version = '27.0.0'
-android_sdk_platform = 'android-21'
+android_sdk_platform = 'android-23'
 
 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)

android/src/Settings.java

@@ -21,10 +21,12 @@ package org.musicpd;
 
 import java.util.LinkedList;
 
+import android.Manifest;
 import android.app.Activity;
 import android.content.Context;
 import android.content.SharedPreferences;
 import android.content.SharedPreferences.Editor;
+import android.content.pm.PackageManager;
 import android.os.Bundle;
 import android.os.Handler;
 import android.os.Message;
@@ -178,6 +180,14 @@ public class Settings extends Activity {
 
 	@Override
 	protected void onCreate(Bundle savedInstanceState) {
+		/* TODO: this sure is the wrong place to request
+		   permissions - it will cause MPD to quit
+		   immediately; we should request permissions when we
+		   need them, but implementing that is complicated, so
+		   for now, we do it here to give users a quick
+		   solution for the problem */
+		requestAllPermissions();
+
 		setContentView(R.layout.settings);
 		mRunButton = (ToggleButton) findViewById(R.id.run);
 		mRunButton.setOnCheckedChangeListener(mOnRunChangeListener);
@@ -203,6 +213,31 @@ public class Settings extends Activity {
 		super.onCreate(savedInstanceState);
 	}
 
+	private void checkRequestPermission(String permission) {
+		if (checkSelfPermission(permission) == PackageManager.PERMISSION_GRANTED)
+			return;
+
+		try {
+			this.requestPermissions(new String[]{permission}, 0);
+		} catch (Exception e) {
+			Log.e(TAG, "requestPermissions(" + permission + ") failed",
+			      e);
+		}
+	}
+
+	private void requestAllPermissions() {
+		if (android.os.Build.VERSION.SDK_INT < 23)
+			/* we don't need to request permissions on
+			   this old Android version */
+			return;
+
+		/* starting with Android 6.0, we need to explicitly
+		   request all permissions before using them;
+		   mentioning them in the manifest is not enough */
+
+		checkRequestPermission(Manifest.permission.READ_EXTERNAL_STORAGE);
+	}
+
 	private void connectClient() {
 		mClient = new Main.Client(this, new Main.Client.Callback() {
 

doc/conf.py

@@ -38,7 +38,7 @@ author = 'Max Kellermann'
 # built documents.
 #
 # The short X.Y version.
-version = '0.21.7'
+version = '0.21.9'
 # The full version, including alpha/beta/rc tags.
 release = version
 

doc/developer.rst

@@ -96,10 +96,8 @@ When the whole patch series is finished, convert stgit patches to git commits:
 Submitting Patches
 ==================
 
-Send your patches to the mailing list:
-Email: `mpd-devel <mpd-devel@musicpd.org>`_
-
-:program:`git pull` requests are preferred.
+Submit pull requests on GitHub:
+https://github.com/MusicPlayerDaemon/MPD/pulls
 
 Development Tools
 =================

doc/mpd.conf.5

@@ -140,7 +140,6 @@ of database.
 .B auto_update_depth <N>
 Limit the depth of the directories being watched, 0 means only watch
 the music directory itself.  There is no limit by default.
-.TP
 .SH REQUIRED AUDIO OUTPUT PARAMETERS
 .TP
 .B type <type>
@@ -164,57 +163,12 @@ Specifies how replay gain is applied.  The default is "software",
 which uses an internal software volume control.  "mixer" uses the
 configured (hardware) mixer control.  "none" disables replay gain on
 this audio output.
-.SH OPTIONAL ALSA OUTPUT PARAMETERS
-.TP
-.B device <dev>
-This specifies the device to use for audio output.  The default is "default".
 .TP
 .B mixer_type <hardware, software or none>
 Specifies which mixer should be used for this audio output: the
 hardware mixer (available for ALSA, OSS and PulseAudio), the software
 mixer or no mixer ("none").  By default, the hardware mixer is used
 for devices which support it, and none for the others.
-.TP
-.B mixer_device <mixer dev>
-This specifies which mixer to use.  The default is "default".  To use
-the second sound card in a system, use "hw:1".
-.TP
-.B mixer_control <mixer ctrl>
-This specifies which mixer control to use (sometimes referred to as
-the "device").  The default is "PCM".  Use "amixer scontrols" to see
-the list of possible controls.
-.TP
-.B mixer_index <mixer index>
-A number identifying the index of the named mixer control.  This is
-probably only useful if your alsa device has more than one
-identically\-named mixer control.  The default is "0".  Use "amixer
-scontrols" to see the list of controls with their indexes.
-.TP
-.B auto_resample <yes or no>
-Setting this to "no" disables ALSA's software resampling, if the
-hardware does not support a specific sample rate.  This lets MPD do
-the resampling.  "yes" is the default and allows ALSA to resample.
-.TP
-.B auto_channels <yes or no>
-Setting this to "no" disables ALSA's channel conversion, if the
-hardware does not support a specific number of channels.  Default: "yes".
-.TP
-.B auto_format <yes or no>
-Setting this to "no" disables ALSA's sample format conversion, if the
-hardware does not support a specific sample format.  Default: "yes".
-.TP
-.B buffer_time <time in microseconds>
-This sets the length of the hardware sample buffer in microseconds.  Increasing
-it may help to reduce or eliminate skipping on certain setups.  Most users do
-not need to change this.  The default is 500000 microseconds (0.5 seconds).
-.TP
-.B period_time <time in microseconds>
-This sets the time between hardware sample transfers in microseconds.
-Increasing this can reduce CPU usage while lowering it can reduce underrun
-errors on bandwidth-limited devices.  Some users have reported good results
-with this set to 50000, but not all devices support values this high.  Most
-users do not need to change this.  The default is 256000000 / sample_rate(kHz),
-or 5804 microseconds for CD-quality audio.
 .SH FILES
 .TP
 .BI ~/.mpdconf

doc/protocol.rst

@@ -14,6 +14,9 @@ Once the client is connected to the server, they conduct a
 conversation until the client closes the connection. The
 conversation flow is always initiated by the client.
 
+All data between the client and the server is encoded in
+UTF-8.
+
 The client transmits a command sequence, terminated by the
 newline character ``\n``.  The server will
 respond with one or more lines, the last of which will be a
@@ -42,9 +45,6 @@ quotation marks.
 Argument strings are separated from the command and any other
 arguments by linear white-space (' ' or '\\t').
 
-All data between the client and the server is encoded in
-UTF-8.
-
 Responses
 =========
 
@@ -52,6 +52,28 @@ A command returns ``OK`` on completion or
 ``ACK some error`` on failure.  These
 denote the end of command execution.
 
+Some commands return more data before the response ends with ``OK``.
+Each line is usually in the form ``NAME: VALUE``.  Example::
+
+  foo: bar
+  OK
+
+.. _binary:
+
+Binary Responses
+----------------
+
+Some commands can return binary data.  This is initiated by a line
+containing ``binary: 1234`` (followed as usual by a newline).  After
+that, the specified number of bytes of binary data follows (without an
+extra newline, because this binary data is not a text line), and
+finally the ``OK`` line.  Example::
+
+  foo: bar
+  binary: 42
+  <42 bytes>OK
+
+
 Failure responses
 -----------------
 
@@ -112,9 +134,9 @@ list begins with `command_list_begin` or
 `command_list_ok_begin` and ends with
 `command_list_end`.
 
-It does not execute any commands until the list has ended.
-The return value is whatever the return for a list of commands
-is.  On success for all commands,
+It does not execute any commands until the list has ended.  The
+response is a concatentation of all individual responses.
+On success for all commands,
 ``OK`` is returned.  If a command
 fails, no more commands are executed and the appropriate
 ``ACK`` error is returned. If
@@ -178,8 +200,9 @@ of:
   file's time stamp with the given value (ISO 8601 or UNIX
   time stamp).
 
-- ``(AudioFormat == 'SAMPLERATE:BITS:CHANNELS')``:
-  compares the audio format with the given value.
+- ``(AudioFormat == 'SAMPLERATE:BITS:CHANNELS')``: compares the audio
+  format with the given value.  See :ref:`audio_output_format` for a
+  detailed explanation.
 
 - ``(AudioFormat =~ 'SAMPLERATE:BITS:CHANNELS')``:
   matches the audio format with the given mask (i.e. one
@@ -414,15 +437,18 @@ Querying :program:`MPD`'s status
     - ``songid``: playlist songid of the current song stopped on or playing
     - ``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)
+    - ``time``: total time elapsed (of current playing/paused song) in seconds
       (deprecated, use ``elapsed`` instead)
-    - ``elapsed`` [#since_0_16]_: Total time elapsed within the current song, but with higher resolution.
+    - ``elapsed`` [#since_0_16]_: Total time elapsed within the
+      current song in seconds, but with higher resolution.
     - ``duration`` [#since_0_20]_: Duration of the current song in seconds.
     - ``bitrate``: instantaneous bitrate in kbps
     - ``xfade``: ``crossfade`` in seconds
     - ``mixrampdb``: ``mixramp`` threshold in dB
     - ``mixrampdelay``: ``mixrampdelay`` in seconds
-    - ``audio``: The format emitted by the decoder plugin during playback, format: ``*samplerate:bits:channels*``. Check the user manual for a detailed explanation.
+    - ``audio``: The format emitted by the decoder plugin during
+      playback, format: ``samplerate:bits:channels``.  See
+      :ref:`audio_output_format` for a detailed explanation.
     - ``updating_db``: ``job id``
     - ``error``: if there is an error, returns message here
 
@@ -437,7 +463,7 @@ Querying :program:`MPD`'s status
     - ``albums``: number of albums
     - ``songs``: number of songs
     - ``uptime``: daemon uptime in seconds
-    - ``db_playtime``: sum of all song times in the db
+    - ``db_playtime``: sum of all song times in the database in seconds
     - ``db_update``: last db update in UNIX time
     - ``playtime``: time length of music played
 
@@ -599,7 +625,7 @@ Whenever possible, ids should be used.
     Deletes the song ``SONGID`` from the
     playlist
 
-:command:`move {FROM} [{START:END} | {TO}]`
+:command:`move [{FROM} | {START:END}] {TO}`
     Moves the song at ``FROM`` or range of songs
     at ``START:END`` [#since_0_15]_ to ``TO``
     in the playlist.
@@ -790,7 +816,7 @@ The music database
 
     Returns the file size and actual number
     of bytes read at the requested offset, followed
-    by the chunk requested as raw bytes, then a
+    by the chunk requested as raw bytes (see :ref:`binary`), then a
     newline and the completion code.
 
     Example::
@@ -798,8 +824,7 @@ The music database
      albumart
      size: 1024768
      binary: 8192
-     <8192 bytes>
-     OK
+     <8192 bytes>OK
 
 :command:`count {FILTER} [group {GROUPTYPE}]`
     Count the number of songs and their total playtime in
@@ -860,8 +885,7 @@ The music database
 :command:`list {TYPE} {FILTER} [group {GROUPTYPE}]`
     Lists unique tags values of the specified type.
     ``TYPE`` can be any tag supported by
-    :program:`MPD` or
-    *file*.
+    :program:`MPD`.
 
     Additional arguments may specify a :ref:`filter <filter_syntax>`.
     The *group* keyword may be used
@@ -872,6 +896,10 @@ The music database
 
      list album group albumartist
 
+    ``list file`` was implemented in an early :program:`MPD` version,
+    but does not appear to make a lot of sense.  It still works (to
+    avoid breaking compatibility), but is deprecated.
+
 .. _command_listall:
 
 :command:`listall [URI]`
@@ -1053,7 +1081,8 @@ Stickers
 "Stickers" [#since_0_15]_ are pieces of
 information attached to existing
 :program:`MPD` objects (e.g. song files,
-directories, albums).  Clients can create arbitrary name/value
+directories, albums; but currently, they are only implemented for
+song).  Clients can create arbitrary name/value
 pairs.  :program:`MPD` itself does not assume
 any special meaning in them.
 

doc/user.rst

@@ -402,14 +402,9 @@ The following table lists the audio_output options valid for all plugins:
      - The name of the plugin
    * - **name**
      - The name of the audio output. It is visible to the client. Some plugins also use it internally, e.g. as a name registered in the PULSE server.
-   * - **format**
-     -  Always open the audio output with the specified audio format samplerate:bits:channels), regardless of the format of the input file. This is optional for most plugins.
-
-        Any of the three attributes may be an asterisk to specify that this attribute should not be enforced, example: 48000:16:*. *:*:* is equal to not having a format specification.
-
-        The following values are valid for bits: 8 (signed 8 bit integer samples), 16, 24 (signed 24 bit integer samples padded to 32 bit), 32 (signed 32 bit integer samples), f (32 bit floating point, -1.0 to 1.0), "dsd" means DSD (Direct Stream Digital). For DSD, there are special cases such as "dsd64", which allows you to omit the sample rate (e.g. dsd512:2 for stereo DSD512, i.e. 22.5792 MHz).
-
-        The sample rate is special for DSD: :program:`MPD` counts the number of bytes, not bits. Thus, a DSD "bit" rate of 22.5792 MHz (DSD512) is 2822400 from :program:`MPD`'s point of view (44100*512/8).
+   * - **format samplerate:bits:channels**
+     -  Always open the audio output with the specified audio format, regardless of the format of the input file. This is optional for most plugins.
+        See :ref:`audio_output_format` for a detailed description of the value.
    * - **enabed yes|no**
      - Specifies whether this audio output is enabled when :program:`MPD` is started. By default, all audio outputs are enabled. This is just the default setting when there is no state file; with a state file, the previous state is restored.
    * - **tags yes|no**
@@ -504,10 +499,31 @@ reference.
 Audio Format Settings
 ---------------------
 
+.. _audio_output_format:
+
 Global Audio Format
 ~~~~~~~~~~~~~~~~~~~
 
-The setting audio_output_format forces :program:`MPD` to use one audio format for all outputs. Doing that is usually not a good idea. The values are the same as in format in the audio_output section.
+The setting ``audio_output_format`` forces :program:`MPD` to use one
+audio format for all outputs.  Doing that is usually not a good idea.
+
+The value is specified as ``samplerate:bits:channels``.
+
+Any of the three attributes may be an asterisk to specify that this
+attribute should not be enforced, example: ``48000:16:*``.
+``*:*:*`` is equal to not having a format specification.
+
+The following values are valid for bits: ``8`` (signed 8 bit integer
+samples), ``16``, ``24`` (signed 24 bit integer samples padded to 32
+bit), ``32`` (signed 32 bit integer samples), ``f`` (32 bit floating
+point, -1.0 to 1.0), ``dsd`` means DSD (Direct Stream Digital). For
+DSD, there are special cases such as ``dsd64``, which allows you to
+omit the sample rate (e.g. ``dsd512:2`` for stereo DSD512,
+i.e. 22.5792 MHz).
+
+The sample rate is special for DSD: :program:`MPD` counts the number
+of bytes, not bits. Thus, a DSD "bit" rate of 22.5792 MHz (DSD512) is
+2822400 from :program:`MPD`'s point of view (44100*512/8).
 
 Resampler
 ~~~~~~~~~
@@ -885,7 +901,7 @@ To verify if :program:`MPD` converts the audio format, enable verbose logging, a
 .. code-block:: none
 
     decoder: audio_format=44100:24:2, seekable=true
-    output: opened plugin=alsa name="An ALSA output"audio_format=44100:16:2
+    output: opened plugin=alsa name="An ALSA output" audio_format=44100:16:2
     output: converting from 44100:24:2
 
 This example shows that a 24 bit file is being played, but the sound chip cannot play 24 bit. It falls back to 16 bit, discarding 8 bit.
@@ -912,7 +928,7 @@ Check list for bit-perfect playback:
   device (:samp:`hw:0,0` or similar).
 * Don't use software volume (setting :code:`mixer_type`).
 * Don't force :program:`MPD` to use a specific audio format (settings
-  :code:`format`, :code:`audio_output_format`).
+  :code:`format`, :ref:`audio_output_format <audio_output_format>`).
 * Verify that you are really doing bit-perfect playback using :program:`MPD`'s verbose log and :file:`/proc/asound/card*/pcm*p/sub*/hw_params`. Some DACs can also indicate the audio format.
 
 Direct Stream Digital (DSD)

meson.build

@@ -1,7 +1,7 @@
 project(
   'mpd',
   ['c', 'cpp'],
-  version: '0.21.7',
+  version: '0.21.9',
   meson_version: '>= 0.49.0',
   default_options: [
     'c_std=c99',
@@ -367,8 +367,10 @@ basic_dep = declare_dependency(
 
 if enable_database
   subdir('src/storage')
-  subdir('src/db')
+else
+  storage_glue_dep = dependency('', required: false)
 endif
+subdir('src/db')
 
 if neighbor_glue_dep.found()
   sources += 'src/command/NeighborCommands.cxx'

python/build/libs.py

@@ -392,7 +392,7 @@ libnfs = AutotoolsProject(
 )
 
 boost = BoostProject(
-    'http://downloads.sourceforge.net/project/boost/boost/1.69.0/boost_1_69_0.tar.bz2',
-    '8f32d4617390d1c2d16f26a27ab60d97807b35440d45891fa340fc2648b04406',
+    'http://downloads.sourceforge.net/project/boost/boost/1.70.0/boost_1_70_0.tar.bz2',
+    '430ae8354789de4fd19ee52f3b1f739e1fba576f0aded0897c3c2bc00fb38778',
     'include/boost/version.hpp',
 )

src/CommandLine.cxx

@@ -108,17 +108,17 @@ static constexpr Domain cmdline_domain("cmdline");
 gcc_noreturn
 static void version(void)
 {
-	printf("Music Player Daemon " VERSION " (%s)\n"
+	printf("Music Player Daemon " VERSION " (%s)"
 	       "\n"
 	       "Copyright 2003-2007 Warren Dukes <warren.dukes@gmail.com>\n"
 	       "Copyright 2008-2018 Max Kellermann <max.kellermann@gmail.com>\n"
 	       "This is free software; see the source for copying conditions.  There is NO\n"
-	       "warranty; not even MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.\n"
+	       "warranty; not even MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.\n",
+	       GIT_VERSION);
 
 #ifdef ENABLE_DATABASE
-	       "\n"
-	       "Database plugins:\n",
-	       GIT_VERSION);
+	printf("\n"
+	       "Database plugins:\n");
 
 	for (auto i = database_plugins; *i != nullptr; ++i)
 		printf(" %s", (*i)->name);
@@ -129,18 +129,18 @@ static void version(void)
 	for (auto i = storage_plugins; *i != nullptr; ++i)
 		printf(" %s", (*i)->name);
 
-	printf("\n"
+	printf("\n");
 #endif
 
 #ifdef ENABLE_NEIGHBOR_PLUGINS
-	       "\n"
+	printf("\n"
 	       "Neighbor plugins:\n");
 	for (auto i = neighbor_plugins; *i != nullptr; ++i)
 		printf(" %s", (*i)->name);
 
-	printf("\n"
 #endif
 
+	printf("\n"
 	       "\n"
 	       "Decoders plugins:\n");
 

src/LocateUri.cxx

@@ -55,14 +55,26 @@ LocateFileUri(const char *uri, const Client *client
 }
 
 static LocatedUri
-LocateAbsoluteUri(const char *uri
+LocateAbsoluteUri(UriPluginKind kind, const char *uri
 #ifdef ENABLE_DATABASE
 		  , const Storage *storage
 #endif
 		  )
 {
-	if (!uri_supported_scheme(uri))
-		throw std::runtime_error("Unsupported URI scheme");
+	switch (kind) {
+	case UriPluginKind::INPUT:
+	case UriPluginKind::STORAGE: // TODO: separate check for storage plugins
+		if (!uri_supported_scheme(uri))
+			throw std::runtime_error("Unsupported URI scheme");
+		break;
+
+	case UriPluginKind::PLAYLIST:
+		/* for now, no validation for playlist URIs; this is
+		   more complicated because there are three ways to
+		   identify which plugin to use: URI scheme, filename
+		   suffix and MIME type */
+		break;
+	}
 
 #ifdef ENABLE_DATABASE
 	if (storage != nullptr) {
@@ -76,7 +88,8 @@ LocateAbsoluteUri(const char *uri
 }
 
 LocatedUri
-LocateUri(const char *uri, const Client *client
+LocateUri(UriPluginKind kind,
+	  const char *uri, const Client *client
 #ifdef ENABLE_DATABASE
 	  , const Storage *storage
 #endif
@@ -100,7 +113,7 @@ LocateUri(const char *uri, const Client *client
 #endif
 				     );
 	else if (uri_has_scheme(uri))
-		return LocateAbsoluteUri(uri
+		return LocateAbsoluteUri(kind, uri
 #ifdef ENABLE_DATABASE
 					 , storage
 #endif

src/LocateUri.hxx

@@ -41,6 +41,12 @@ class Client;
 class Storage;
 #endif
 
+enum class UriPluginKind {
+	INPUT,
+	STORAGE,
+	PLAYLIST,
+};
+
 struct LocatedUri {
 	enum class Type {
 		/**
@@ -84,7 +90,8 @@ struct LocatedUri {
  * that feature is disabled if this parameter is nullptr
  */
 LocatedUri
-LocateUri(const char *uri, const Client *client
+LocateUri(UriPluginKind kind,
+	  const char *uri, const Client *client
 #ifdef ENABLE_DATABASE
 	  , const Storage *storage
 #endif

src/SongLoader.cxx

@@ -94,7 +94,8 @@ SongLoader::LoadSong(const char *uri_utf8) const
 	assert(uri_utf8 != nullptr);
 #endif
 
-	const auto located_uri = LocateUri(uri_utf8, client
+	const auto located_uri = LocateUri(UriPluginKind::INPUT,
+					   uri_utf8, client
 #ifdef ENABLE_DATABASE
 					   , storage
 #endif

src/command/FileCommands.cxx

@@ -218,7 +218,7 @@ handle_read_comments(Client &client, Request args, Response &r)
 
 	const char *const uri = args.front();
 
-	const auto located_uri = LocateUri(uri, &client
+	const auto located_uri = LocateUri(UriPluginKind::INPUT, uri, &client
 #ifdef ENABLE_DATABASE
 					   , nullptr
 #endif
@@ -331,7 +331,7 @@ handle_album_art(Client &client, Request args, Response &r)
 	const char *uri = args.front();
 	size_t offset = args.ParseUnsigned(1);
 
-	const auto located_uri = LocateUri(uri, &client
+	const auto located_uri = LocateUri(UriPluginKind::INPUT, uri, &client
 #ifdef ENABLE_DATABASE
 					   , nullptr
 #endif

src/command/OtherCommands.cxx

@@ -99,7 +99,7 @@ handle_listfiles(Client &client, Request args, Response &r)
 	/* default is root directory */
 	const auto uri = args.GetOptional(0, "");
 
-	const auto located_uri = LocateUri(uri, &client
+	const auto located_uri = LocateUri(UriPluginKind::STORAGE, uri, &client
 #ifdef ENABLE_DATABASE
 					   , nullptr
 #endif
@@ -219,7 +219,7 @@ handle_lsinfo(Client &client, Request args, Response &r)
 		   compatibility, work around this here */
 		uri = "";
 
-	const auto located_uri = LocateUri(uri, &client
+	const auto located_uri = LocateUri(UriPluginKind::INPUT, uri, &client
 #ifdef ENABLE_DATABASE
 					   , nullptr
 #endif

src/command/PlaylistCommands.cxx

@@ -69,7 +69,8 @@ handle_save(Client &client, Request args, gcc_unused Response &r)
 CommandResult
 handle_load(Client &client, Request args, gcc_unused Response &r)
 {
-	const auto uri = LocateUri(args.front(), &client
+	const auto uri = LocateUri(UriPluginKind::PLAYLIST, args.front(),
+				   &client
 #ifdef ENABLE_DATABASE
 					   , nullptr
 #endif
@@ -99,7 +100,8 @@ handle_load(Client &client, Request args, gcc_unused Response &r)
 CommandResult
 handle_listplaylist(Client &client, Request args, Response &r)
 {
-	const auto name = LocateUri(args.front(), &client
+	const auto name = LocateUri(UriPluginKind::PLAYLIST, args.front(),
+				    &client
 #ifdef ENABLE_DATABASE
 					   , nullptr
 #endif
@@ -115,7 +117,8 @@ handle_listplaylist(Client &client, Request args, Response &r)
 CommandResult
 handle_listplaylistinfo(Client &client, Request args, Response &r)
 {
-	const auto name = LocateUri(args.front(), &client
+	const auto name = LocateUri(UriPluginKind::PLAYLIST, args.front(),
+				    &client
 #ifdef ENABLE_DATABASE
 					   , nullptr
 #endif

src/command/QueueCommands.cxx

@@ -83,7 +83,8 @@ handle_add(Client &client, Request args, Response &r)
 		   here */
 		uri = "";
 
-	const auto located_uri = LocateUri(uri, &client
+	const auto located_uri = LocateUri(UriPluginKind::INPUT, uri,
+					   &client
 #ifdef ENABLE_DATABASE
 					   , nullptr
 #endif

src/db/meson.build

@@ -9,6 +9,11 @@ db_api_dep = declare_dependency(
   link_with: db_api,
 )
 
+if not enable_database
+  db_glue_dep = db_api_dep
+  subdir_done()
+endif
+
 subdir('plugins')
 
 db_glue_sources = [

src/db/plugins/ProxyDatabasePlugin.cxx

@@ -568,7 +568,8 @@ ProxyDatabase::OnSocketReady(gcc_unused unsigned flags) noexcept
 	if (!is_idle) {
 		// TODO: can this happen?
 		IdleMonitor::Schedule();
-		return false;
+		SocketMonitor::Cancel();
+		return true;
 	}
 
 	unsigned idle = (unsigned)mpd_recv_idle(connection, false);
@@ -586,7 +587,8 @@ ProxyDatabase::OnSocketReady(gcc_unused unsigned flags) noexcept
 	idle_received |= idle;
 	is_idle = false;
 	IdleMonitor::Schedule();
-	return false;
+	SocketMonitor::Cancel();
+	return true;
 }
 
 void

src/event/BufferedSocket.cxx

@@ -110,15 +110,9 @@ BufferedSocket::OnSocketReady(unsigned flags) noexcept
 	if (flags & READ) {
 		assert(!input.IsFull());
 
-		if (!ReadToBuffer())
+		if (!ReadToBuffer() || !ResumeInput())
 			return false;
 
-		if (!ResumeInput())
-			/* we must return "true" here or
-			   SocketMonitor::Dispatch() will call
-			   Cancel() on a freed object */
-			return true;
-
 		if (!input.IsFull())
 			ScheduleRead();
 	}

src/event/BufferedSocket.hxx

@@ -46,6 +46,11 @@ public:
 	using SocketMonitor::Close;
 
 private:
+	/**
+	 * @return the number of bytes read from the socket, 0 if the
+	 * socket isn't ready for reading, -1 on error (the socket has
+	 * been closed and probably destructed)
+	 */
 	ssize_t DirectRead(void *data, size_t length) noexcept;
 
 	/**

src/event/FullyBufferedSocket.hxx

@@ -45,6 +45,11 @@ public:
 	}
 
 private:
+	/**
+	 * @return the number of bytes written to the socket, 0 if the
+	 * socket isn't ready for writing, -1 on error (the socket has
+	 * been closed and probably destructed)
+	 */
 	ssize_t DirectWrite(const void *data, size_t length) noexcept;
 
 protected:

src/event/SocketMonitor.cxx

@@ -33,8 +33,8 @@ SocketMonitor::Dispatch(unsigned flags) noexcept
 {
 	flags &= GetScheduledFlags();
 
-	if (flags != 0 && !OnSocketReady(flags) && IsDefined())
-		Cancel();
+	if (flags != 0)
+		OnSocketReady(flags);
 }
 
 SocketMonitor::~SocketMonitor() noexcept

src/input/BufferedInputStream.cxx

@@ -59,6 +59,9 @@ BufferedInputStream::~BufferedInputStream() noexcept
 void
 BufferedInputStream::Check()
 {
+	if (read_error)
+		std::rethrow_exception(read_error);
+
 	if (input)
 		input->Check();
 }
@@ -101,7 +104,7 @@ BufferedInputStream::IsEOF() noexcept
 bool
 BufferedInputStream::IsAvailable() noexcept
 {
-	return IsEOF() || buffer.Read(offset).HasData();
+	return IsEOF() || buffer.Read(offset).HasData() || read_error;
 }
 
 size_t
@@ -164,6 +167,32 @@ BufferedInputStream::RunThread() noexcept
 			idle = false;
 			seek = false;
 			client_cond.signal();
+		} else if (!idle && !read_error &&
+			   offset != input->GetOffset() &&
+			   !IsAvailable()) {
+			/* a past Seek() call was a no-op because data
+			   was already available at that position, but
+			   now we've reached a new position where
+			   there is no more data in the buffer, and
+			   our input is reading somewhere else (maybe
+			   stuck at the end of the file); to find a
+			   way out, we now seek our input to our
+			   reading position to be able to fill our
+			   buffer */
+
+			try {
+				input->Seek(offset);
+			} catch (...) {
+				/* this is really a seek error, but we
+				   register it as a read_error,
+				   because seek_error is only checked
+				   by Seek(), and at our frontend (our
+				   own InputStream interface) is in
+				   "read" mode */
+				read_error = std::current_exception();
+				client_cond.signal();
+				InvokeOnAvailable();
+			}
 		} else if (!idle && !read_error &&
 			   input->IsAvailable() && !input->IsEOF()) {
 			const auto read_offset = input->GetOffset();

src/input/plugins/SmbclientInputPlugin.cxx

@@ -22,6 +22,7 @@
 #include "lib/smbclient/Mutex.hxx"
 #include "../InputStream.hxx"
 #include "../InputPlugin.hxx"
+#include "../MaybeBufferedInputStream.hxx"
 #include "PluginUnavailable.hxx"
 #include "system/Error.hxx"
 #include "util/ASCII.hxx"
@@ -112,8 +113,9 @@ input_smbclient_open(const char *uri,
 		throw MakeErrno(e, "smbc_fstat() failed");
 	}
 
-	return std::make_unique<SmbclientInputStream>(uri, mutex,
-						      ctx, fd, st);
+	return std::make_unique<MaybeBufferedInputStream>
+		(std::make_unique<SmbclientInputStream>(uri, mutex,
+							ctx, fd, st));
 }
 
 size_t

src/neighbor/plugins/SmbclientNeighborPlugin.cxx

@@ -150,8 +150,6 @@ ReadServers(NeighborExplorer::List &list, int fd)
 	smbc_dirent *e;
 	while ((e = smbc_readdir(fd)) != nullptr)
 		ReadEntry(list, *e);
-
-	smbc_closedir(fd);
 }
 
 static void

src/net/IPv4Address.hxx

@@ -168,7 +168,7 @@ public:
 	}
 
 	constexpr operator SocketAddress() const noexcept {
-		return SocketAddress((const struct sockaddr *)&address,
+		return SocketAddress((const struct sockaddr *)(const void *)&address,
 				     sizeof(address));
 	}
 

src/net/IPv6Address.hxx

@@ -135,7 +135,7 @@ public:
 	}
 
 	constexpr operator SocketAddress() const noexcept {
-		return SocketAddress((const struct sockaddr *)&address,
+		return SocketAddress((const struct sockaddr *)(const void *)&address,
 				     sizeof(address));
 	}
 

src/output/plugins/httpd/HttpdClient.cxx

@@ -154,7 +154,7 @@ HttpdClient::SendResponse() noexcept
 		FormatWarning(httpd_output_domain,
 			      "failed to write to client: %s",
 			      (const char *)msg);
-		Close();
+		LockClose();
 		return false;
 	}
 
@@ -428,6 +428,7 @@ void
 HttpdClient::OnSocketError(std::exception_ptr ep) noexcept
 {
 	LogError(ep);
+	LockClose();
 }
 
 void

src/output/plugins/httpd/HttpdClient.hxx

@@ -142,6 +142,8 @@ public:
 
 	/**
 	 * Frees the client and removes it from the server's client list.
+	 *
+	 * Caller must lock the mutex.
 	 */
 	void Close() noexcept;
 

src/output/plugins/httpd/HttpdInternal.hxx

@@ -208,10 +208,15 @@ public:
 		return HasClients();
 	}
 
+	/**
+	 * Caller must lock the mutex.
+	 */
 	void AddClient(UniqueSocketDescriptor fd) noexcept;
 
 	/**
 	 * Removes a client from the httpd_output.clients linked list.
+	 *
+	 * Caller must lock the mutex.
 	 */
 	void RemoveClient(HttpdClient &client) noexcept;
 
@@ -239,10 +244,14 @@ public:
 
 	/**
 	 * Broadcasts data from the encoder to all clients.
+	 *
+	 * Mutext must not be locked.
 	 */
 	void BroadcastFromEncoder();
 
 	/**
+	 * Mutext must not be locked.
+	 *
 	 * Throws #std::runtime_error on error.
 	 */
 	void EncodeAndPlay(const void *chunk, size_t size);
@@ -251,6 +260,9 @@ public:
 
 	size_t Play(const void *chunk, size_t size) override;
 
+	/**
+	 * Mutext must not be locked.
+	 */
 	void CancelAllClients() noexcept;
 
 	void Cancel() noexcept override;

src/player/Thread.cxx

@@ -996,7 +996,7 @@ Player::Run() noexcept
 			}
 		}
 
-		if (dc.IsIdle() && queued && dc.pipe == pipe) {
+		if (dc.IsIdle() && queued) {
 			/* the decoder has finished the current song;
 			   make it decode the next song */
 
@@ -1058,6 +1058,16 @@ Player::Run() noexcept
 
 			SongBorder();
 		} else if (dc.IsIdle()) {
+			if (queued)
+				/* the decoder has just stopped,
+				   between the two IsIdle() checks,
+				   probably while UnlockCheckOutputs()
+				   left the mutex unlocked; to restart
+				   the decoder instead of stopping
+				   playback completely, let's re-enter
+				   this loop */
+				continue;
+
 			/* check the size of the pipe again, because
 			   the decoder thread may have added something
 			   since we last checked */

src/zeroconf/ZeroconfBonjour.cxx

@@ -50,7 +50,7 @@ protected:
 	/* virtual methods from class SocketMonitor */
 	bool OnSocketReady(gcc_unused unsigned flags) noexcept override {
 		DNSServiceProcessResult(service_ref);
-		return false;
+		return true;
 	}
 };
 

systemd/system/mpd.socket

@@ -1,5 +1,5 @@
 [Socket]
-ListenStream=/run/mpd/socket
+ListenStream=%t/mpd/socket
 ListenStream=6600
 Backlog=5
 KeepAlive=true

systemd/user/meson.build

@@ -3,6 +3,12 @@ if systemd_user_unit_dir == ''
   systemd_user_unit_dir = join_paths(get_option('prefix'), 'lib', 'systemd', 'user')
 endif
 
+# copy the system socket unit to the "user" directory
+install_data(
+  join_paths('..', 'system', 'mpd.socket'),
+  install_dir: systemd_user_unit_dir,
+)
+
 configure_file(
   input: 'mpd.service.in',
   output: 'mpd.service',