release v0.20.1

Call SeekDone() to avoid the freeze bug.

Makefile.am

@@ -233,6 +233,15 @@ libmpd_a_SOURCES += \
 	src/db/Selection.cxx src/db/Selection.hxx
 endif
 
+CURL_SOURCES = \
+	src/lib/curl/Version.cxx src/lib/curl/Version.hxx \
+	src/lib/curl/Global.cxx src/lib/curl/Global.hxx \
+	src/lib/curl/Request.cxx src/lib/curl/Request.hxx \
+	src/lib/curl/Handler.hxx \
+	src/lib/curl/Easy.hxx \
+	src/lib/curl/Multi.hxx \
+	src/lib/curl/Slist.hxx
+
 UPNP_SOURCES = \
 	src/lib/upnp/Init.cxx src/lib/upnp/Init.hxx \
 	src/lib/upnp/ClientInit.cxx src/lib/upnp/ClientInit.hxx \
@@ -420,6 +429,7 @@ libutil_a_SOURCES = \
 	src/util/FormatString.cxx src/util/FormatString.hxx \
 	src/util/Tokenizer.cxx src/util/Tokenizer.hxx \
 	src/util/TextFile.hxx \
+	src/util/TimeParser.cxx src/util/TimeParser.hxx \
 	src/util/UriUtil.cxx src/util/UriUtil.hxx \
 	src/util/Manual.hxx \
 	src/util/RefCount.hxx \
@@ -689,6 +699,8 @@ libstorage_a_CPPFLAGS = $(AM_CPPFLAGS) \
 
 STORAGE_LIBS = \
 	libstorage.a \
+	$(CURL_LIBS) \
+	$(EXPAT_LIBS) \
 	$(NFS_LIBS) \
 	$(SMBCLIENT_LIBS)
 
@@ -704,6 +716,12 @@ libstorage_a_SOURCES += \
 	src/storage/plugins/NfsStorage.cxx src/storage/plugins/NfsStorage.hxx
 endif
 
+if ENABLE_WEBDAV
+libstorage_a_SOURCES += \
+	src/lib/expat/ExpatParser.cxx \
+	src/storage/plugins/CurlStorage.cxx src/storage/plugins/CurlStorage.hxx
+endif
+
 endif
 
 # neighbor plugins
@@ -1279,12 +1297,7 @@ if ENABLE_CURL
 libinput_a_SOURCES += \
 	src/input/IcyInputStream.cxx src/input/IcyInputStream.hxx \
 	src/input/plugins/CurlInputPlugin.cxx src/input/plugins/CurlInputPlugin.hxx \
-	src/lib/curl/Version.cxx src/lib/curl/Version.hxx \
-	src/lib/curl/Global.cxx src/lib/curl/Global.hxx \
-	src/lib/curl/Request.cxx src/lib/curl/Request.hxx \
-	src/lib/curl/Handler.hxx \
-	src/lib/curl/Easy.hxx \
-	src/lib/curl/Multi.hxx \
+	$(CURL_SOURCES) \
 	src/IcyMetaDataParser.cxx src/IcyMetaDataParser.hxx
 endif
 
@@ -1382,6 +1395,7 @@ libmixer_plugins_a_SOURCES = \
 	src/mixer/plugins/NullMixerPlugin.cxx \
 	src/mixer/plugins/SoftwareMixerPlugin.cxx \
 	src/mixer/plugins/SoftwareMixerPlugin.hxx
+
 libmixer_plugins_a_CPPFLAGS = $(AM_CPPFLAGS) \
 	$(ALSA_CFLAGS) \
 	$(PULSE_CFLAGS)
@@ -1390,7 +1404,10 @@ if ENABLE_ALSA
 liboutput_plugins_a_SOURCES += \
 	src/output/plugins/AlsaOutputPlugin.cxx \
 	src/output/plugins/AlsaOutputPlugin.hxx
-libmixer_plugins_a_SOURCES += src/mixer/plugins/AlsaMixerPlugin.cxx
+libmixer_plugins_a_SOURCES += \
+	src/mixer/plugins/volume_mapping.h \
+	src/mixer/plugins/volume_mapping.c \
+	src/mixer/plugins/AlsaMixerPlugin.cxx
 endif
 
 if ANDROID
@@ -1573,6 +1590,7 @@ endif
 
 if ENABLE_EXPAT
 libplaylist_plugins_a_SOURCES += \
+	src/lib/expat/StreamExpatParser.cxx \
 	src/lib/expat/ExpatParser.cxx src/lib/expat/ExpatParser.hxx \
 	src/playlist/plugins/XspfPlaylistPlugin.cxx \
 	src/playlist/plugins/XspfPlaylistPlugin.hxx \
@@ -1758,6 +1776,10 @@ test_run_storage_SOURCES = \
 	test/ScopeIOThread.hxx \
 	test/run_storage.cxx
 
+if ENABLE_WEBDAV
+test_run_storage_SOURCES += $(CURL_SOURCES)
+endif
+
 endif
 
 test_run_input_LDADD = \

NEWS

@@ -1,3 +1,15 @@
+ver 0.20.1 (2017/01/09)
+* input
+  - curl: fix crash bug
+  - curl: fix freeze bug
+* decoder
+  - wavpack: fix crash bug
+* storage
+  - curl: new storage plugin for WebDAV (work in progress)
+* mixer
+  - alsa: normalize displayed volume according to human perception
+* fix crash with volume_normalization enabled
+
 ver 0.20 (2017/01/04)
 * protocol
   - "commands" returns playlist commands only if playlist_directory configured

configure.ac

@@ -1,10 +1,10 @@
 AC_PREREQ(2.60)
 
-AC_INIT(mpd, 0.20, musicpd-dev-team@lists.sourceforge.net)
+AC_INIT(mpd, 0.20.1, musicpd-dev-team@lists.sourceforge.net)
 
 VERSION_MAJOR=0
 VERSION_MINOR=20
-VERSION_REVISION=0
+VERSION_REVISION=1
 VERSION_EXTRA=0
 
 AC_CONFIG_SRCDIR([src/Main.cxx])
@@ -720,6 +720,19 @@ fi
 MPD_ENABLE_AUTO_PKG(mms, MMS, [libmms >= 0.4],
 	[libmms mms:// protocol support], [libmms not found])
 
+dnl ---------------------------------------------------------------------------
+dnl Storage Plugins
+dnl ---------------------------------------------------------------------------
+
+MPD_ENABLE_AUTO(webdav, WEBDAV, [WebDAV storage plugin],
+	[WebDAV requires libcurl and libexpat],
+	[auto],
+	[if test x$enable_curl = xyes && test x$enable_expat = xyes; then
+		found_webdav=yes
+	else
+		found_webdav=no
+	fi])
+
 dnl ---------------------------------------------------------------------------
 dnl Playlist Plugins
 dnl ---------------------------------------------------------------------------

doc/developer.xml

@@ -5,7 +5,7 @@
 <book>
   <title>The Music Player Daemon - Developer's Manual</title>
 
-  <chapter>
+  <chapter id="introduction">
     <title>Introduction</title>
 
     <para>
@@ -21,7 +21,7 @@
     </para>
   </chapter>
 
-  <chapter>
+  <chapter id="code_style">
     <title>Code Style</title>
 
     <itemizedlist>
@@ -40,21 +40,47 @@
 
       <listitem>
         <para>
-          the code should be C++11 compliant, and must compile with
+          comment your code, document your APIs
+        </para>
+      </listitem>
+
+      <listitem>
+        <para>
+          the code should be C++14 compliant, and must compile with
           <application>GCC</application> 4.9 and
           <application>clang</application> 3.4
         </para>
       </listitem>
 
+      <listitem>
+        <para>
+          report error conditions with C++ exceptions, preferable
+          derived from <varname>std::runtime_error</varname>
+        </para>
+      </listitem>
+
+      <listitem>
+        <para>
+          all code must be exception-safe
+        </para>
+      </listitem>
+
+      <listitem>
+        <para>
+          classes and functions names use CamelCase; variables are
+          lower-case with words separated by underscore
+        </para>
+      </listitem>
+
       <listitem>
         <para>
           Some example code:
         </para>
 
         <programlisting lang="C">static inline int
-foo(const char *abc, int xyz)
+Foo(const char *abc, int xyz)
 {
-        if (abc == NULL) {
+        if (abc == nullptr) {
                 LogWarning("Foo happened!");
                 return -1;
         }
@@ -66,7 +92,7 @@ foo(const char *abc, int xyz)
     </itemizedlist>
   </chapter>
 
-  <chapter>
+  <chapter id="hacking">
     <title>Hacking The Source</title>
 
     <para>
@@ -151,7 +177,7 @@ foo(const char *abc, int xyz)
     </section>
   </chapter>
 
-  <chapter>
+  <chapter id="submitting_patches">
     <title>Submitting Patches</title>
 
     <para>
@@ -167,9 +193,16 @@ foo(const char *abc, int xyz)
       url="http://git.musicpd.org/account-policy.html">an account on
       git.musicpd.org</ulink>, but any public git repository will do.
     </para>
+
+    <para>
+      There is <ulink url="https://github.com/MaxKellermann/MPD">a
+      mirror of the <application>MPD</application> git repository on
+      GitHub</ulink>, and you can use that as well to submit pull
+      requests.
+    </para>
   </chapter>
 
-  <chapter>
+  <chapter id="tools">
     <title>Development Tools</title>
 
     <section>

doc/user.xml

@@ -1868,11 +1868,23 @@ run</programlisting>
         </para>
       </section>
 
+      <section id="curl_storage">
+        <title><varname>curl</varname></title>
+
+        <para>
+          A WebDAV client using <filename>libcurl</filename>.  It is
+          used when <varname>music_directory</varname> contains a
+          <parameter>http://</parameter> or
+          <parameter>https://</parameter> URI, for example
+          "<parameter>https://the.server/dav/</parameter>".
+        </para>
+      </section>
+
       <section id="smbclient_storage">
         <title><varname>smbclient</varname></title>
 
         <para>
-          Load music files from a SMB/CIFS server.  It used used when
+          Load music files from a SMB/CIFS server.  It is used when
           <varname>music_directory</varname> contains a
           <parameter>smb://</parameter> URI, for example
           "<parameter>smb://myfileserver/Music</parameter>".
@@ -1883,7 +1895,7 @@ run</programlisting>
         <title><varname>nfs</varname></title>
 
         <para>
-          Load music files from a NFS server.  It used used when
+          Load music files from a NFS server.  It is used when
           <varname>music_directory</varname> contains a
           <parameter>nfs://</parameter> URI according to <ulink
           url="http://tools.ietf.org/html/rfc2224">RFC2224</ulink>,

src/SongFilter.cxx

@@ -25,9 +25,12 @@
 #include "util/ConstBuffer.hxx"
 #include "util/StringAPI.hxx"
 #include "util/ASCII.hxx"
+#include "util/TimeParser.hxx"
 #include "util/UriUtil.hxx"
 #include "lib/icu/Collate.hxx"
 
+#include <stdexcept>
+
 #include <assert.h>
 #include <stdlib.h>
 
@@ -180,24 +183,6 @@ SongFilter::~SongFilter()
 	/* this destructor exists here just so it won't get inlined */
 }
 
-#if !defined(__GLIBC__) && !defined(WIN32)
-
-/**
- * Determine the time zone offset in a portable way.
- */
-gcc_const
-static time_t
-GetTimeZoneOffset()
-{
-	time_t t = 1234567890;
-	struct tm tm;
-	tm.tm_isdst = 0;
-	gmtime_r(&t, &tm);
-	return t - mktime(&tm);
-}
-
-#endif
-
 gcc_pure
 static time_t
 ParseTimeStamp(const char *s)
@@ -210,26 +195,13 @@ ParseTimeStamp(const char *s)
 		/* it's an integral UNIX time stamp */
 		return (time_t)value;
 
-#ifdef WIN32
-	/* TODO: emulate strptime()? */
-	return 0;
-#else
-	/* try ISO 8601 */
-
-	struct tm tm;
-	const char *end = strptime(s, "%FT%TZ", &tm);
-	if (end == nullptr || *end != 0)
+	try {
+		/* try ISO 8601 */
+		const auto t = ParseTimePoint(s, "%FT%TZ");
+		return std::chrono::system_clock::to_time_t(t);
+	} catch (const std::runtime_error &) {
 		return 0;
-
-#ifdef __GLIBC__
-	/* timegm() is a GNU extension */
-	return timegm(&tm);
-#else
-	tm.tm_isdst = 0;
-	return mktime(&tm) + GetTimeZoneOffset();
-#endif /* !__GLIBC__ */
-
-#endif /* !WIN32 */
+	}
 }
 
 bool

src/db/plugins/upnp/Directory.cxx

@@ -124,7 +124,7 @@ public:
 	}
 
 protected:
-	virtual void StartElement(const XML_Char *name, const XML_Char **attrs)
+	void StartElement(const XML_Char *name, const XML_Char **attrs) override
 	{
 		if (object.type != UPnPDirObject::Type::UNKNOWN &&
 		    tag_type == TAG_NUM_OF_ITEM_TYPES) {
@@ -188,7 +188,7 @@ protected:
 		}
 	}
 
-	virtual void EndElement(const XML_Char *name)
+	void EndElement(const XML_Char *name) override
 	{
 		if (tag_type != TAG_NUM_OF_ITEM_TYPES) {
 			assert(object.type != UPnPDirObject::Type::UNKNOWN);
@@ -212,7 +212,7 @@ protected:
 		state = NONE;
 	}
 
-	virtual void CharacterData(const XML_Char *s, int len)
+	void CharacterData(const XML_Char *s, int len) override
 	{
 		if (tag_type != TAG_NUM_OF_ITEM_TYPES) {
 			assert(object.type != UPnPDirObject::Type::UNKNOWN);

src/db/plugins/upnp/UpnpDatabasePlugin.cxx

@@ -77,9 +77,9 @@ public:
 	static Database *Create(EventLoop &loop, DatabaseListener &listener,
 				const ConfigBlock &block);
 
-	virtual void Open() override;
-	virtual void Close() override;
-	virtual const LightSong *GetSong(const char *uri_utf8) const override;
+	void Open() override;
+	void Close() override;
+	const LightSong *GetSong(const char *uri_utf8) const override;
 	void ReturnSong(const LightSong *song) const override;
 
 	void Visit(const DatabaseSelection &selection,

src/decoder/plugins/WavpackDecoderPlugin.cxx

@@ -536,7 +536,7 @@ wavpack_streamdecode(DecoderClient &client, InputStream &is)
 	auto is_wvc = wavpack_open_wvc(client, is.GetURI());
 	if (is_wvc) {
 		open_flags |= OPEN_WVC;
-		can_seek &= wvc->is.IsSeekable();
+		can_seek &= is_wvc->IsSeekable();
 
 		wvc.reset(new WavpackInput(&client, *is_wvc));
 	}

src/filter/FilterInternal.hxx

@@ -27,6 +27,7 @@
 
 #include "AudioFormat.hxx"
 
+#include <assert.h>
 #include <stddef.h>
 
 struct AudioFormat;
@@ -36,9 +37,10 @@ class Filter {
 protected:
 	AudioFormat out_audio_format;
 
-	Filter() = default;
 	explicit Filter(AudioFormat _out_audio_format)
-		:out_audio_format(_out_audio_format) {}
+		:out_audio_format(_out_audio_format) {
+		assert(out_audio_format.IsValid());
+	}
 
 public:
 	virtual ~Filter() {}
@@ -56,7 +58,6 @@ public:
 	 * Throws std::runtime_error on error.
 	 *
 	 * @param src the input buffer
-	 * @param error location to store the error occurring
 	 * @return the destination buffer on success (will be
 	 * invalidated by deleting this object or the next FilterPCM()
 	 * call)

src/filter/plugins/AutoConvertFilterPlugin.cxx

@@ -45,7 +45,8 @@ class AutoConvertFilter final : public Filter {
 public:
 	AutoConvertFilter(std::unique_ptr<Filter> &&_filter,
 			  std::unique_ptr<Filter> &&_convert)
-		:filter(std::move(_filter)), convert(std::move(_convert)) {}
+		:Filter(_filter->GetOutAudioFormat()),
+		 filter(std::move(_filter)), convert(std::move(_convert)) {}
 
 	ConstBuffer<void> FilterPCM(ConstBuffer<void> src) override;
 };
@@ -92,11 +93,8 @@ PreparedAutoConvertFilter::Open(AudioFormat &in_audio_format)
 ConstBuffer<void>
 AutoConvertFilter::FilterPCM(ConstBuffer<void> src)
 {
-	if (convert != nullptr) {
+	if (convert != nullptr)
 		src = convert->FilterPCM(src);
-		if (src.IsNull())
-			return nullptr;
-	}
 
 	return filter->FilterPCM(src);
 }

src/filter/plugins/ConvertFilterPlugin.cxx

@@ -57,8 +57,6 @@ public:
 
 class PreparedConvertFilter final : public PreparedFilter {
 public:
-	void Set(const AudioFormat &_out_audio_format);
-
 	Filter *Open(AudioFormat &af) override;
 };
 

src/input/plugins/CurlInputPlugin.cxx

@@ -23,6 +23,7 @@
 #include "lib/curl/Global.hxx"
 #include "lib/curl/Request.hxx"
 #include "lib/curl/Handler.hxx"
+#include "lib/curl/Slist.hxx"
 #include "../AsyncInputStream.hxx"
 #include "../IcyInputStream.hxx"
 #include "../InputPlugin.hxx"
@@ -64,7 +65,7 @@ struct CurlInputStream final : public AsyncInputStream, CurlResponseHandler {
 	/* some buffers which were passed to libcurl, which we have
 	   too free */
 	char range[32];
-	struct curl_slist *request_headers;
+	CurlSlist request_headers;
 
 	CurlRequest *request = nullptr;
 
@@ -75,7 +76,6 @@ struct CurlInputStream final : public AsyncInputStream, CurlResponseHandler {
 		:AsyncInputStream(_url, _mutex, _cond,
 				  CURL_MAX_BUFFERED,
 				  CURL_RESUME_AT),
-		 request_headers(nullptr),
 		 icy(new IcyInputStream(this)) {
 	}
 
@@ -155,8 +155,7 @@ CurlInputStream::FreeEasy()
 	delete request;
 	request = nullptr;
 
-	curl_slist_free_all(request_headers);
-	request_headers = nullptr;
+	request_headers.Clear();
 }
 
 void
@@ -371,10 +370,11 @@ CurlInputStream::InitEasy()
 	request->SetOption(CURLOPT_SSL_VERIFYPEER, verify_peer ? 1l : 0l);
 	request->SetOption(CURLOPT_SSL_VERIFYHOST, verify_host ? 2l : 0l);
 
-	request_headers = nullptr;
-	request_headers = curl_slist_append(request_headers,
-					    "Icy-Metadata: 1");
-	request->SetOption(CURLOPT_HTTPHEADER, request_headers);
+	request_headers.Clear();
+	request_headers.Append("Icy-Metadata: 1");
+	request->SetOption(CURLOPT_HTTPHEADER, request_headers.Get());
+
+	request->Start();
 }
 
 void
@@ -385,11 +385,13 @@ CurlInputStream::SeekInternal(offset_type new_offset)
 	FreeEasy();
 
 	offset = new_offset;
-	if (offset == size)
+	if (offset == size) {
 		/* seek to EOF: simulate empty result; avoid
 		   triggering a "416 Requested Range Not Satisfiable"
 		   response */
+		SeekDone();
 		return;
+	}
 
 	InitEasy();
 

src/lib/curl/Global.cxx

@@ -96,7 +96,7 @@ private:
 };
 
 CurlGlobal::CurlGlobal(EventLoop &_loop)
-	:TimeoutMonitor(_loop)
+	:TimeoutMonitor(_loop), DeferredMonitor(_loop)
 {
 	multi.SetOption(CURLMOPT_SOCKETFUNCTION, CurlSocket::SocketFunction);
 	multi.SetOption(CURLMOPT_SOCKETDATA, this);
@@ -217,25 +217,31 @@ CurlGlobal::ReadInfo()
 	}
 }
 
-int
-CurlGlobal::TimerFunction(gcc_unused CURLM *_global, long timeout_ms, void *userp)
+inline void
+CurlGlobal::UpdateTimeout(long timeout_ms)
 {
-	auto &global = *(CurlGlobal *)userp;
-	assert(_global == global.multi.Get());
-
 	if (timeout_ms < 0) {
-		global.Cancel();
-		return 0;
+		TimeoutMonitor::Cancel();
+		return;
 	}
 
-	if (timeout_ms >= 0 && timeout_ms < 10)
+	if (timeout_ms < 10)
 		/* CURL 7.21.1 likes to report "timeout=0", which
 		   means we're running in a busy loop.  Quite a bad
 		   idea to waste so much CPU.  Let's use a lower limit
 		   of 10ms. */
 		timeout_ms = 10;
 
-	global.Schedule(std::chrono::milliseconds(timeout_ms));
+	TimeoutMonitor::Schedule(std::chrono::milliseconds(timeout_ms));
+}
+
+int
+CurlGlobal::TimerFunction(gcc_unused CURLM *_global, long timeout_ms, void *userp)
+{
+	auto &global = *(CurlGlobal *)userp;
+	assert(_global == global.multi.Get());
+
+	global.UpdateTimeout(timeout_ms);
 	return 0;
 }
 
@@ -256,5 +262,11 @@ CurlGlobal::SocketAction(curl_socket_t fd, int ev_bitmask)
 			    "curl_multi_socket_action() failed: %s",
 			    curl_multi_strerror(mcode));
 
+	DeferredMonitor::Schedule();
+}
+
+void
+CurlGlobal::RunDeferred()
+{
 	ReadInfo();
 }

src/lib/curl/Global.hxx

@@ -32,6 +32,7 @@
 
 #include "Multi.hxx"
 #include "event/TimeoutMonitor.hxx"
+#include "event/DeferredMonitor.hxx"
 
 class CurlSocket;
 class CurlRequest;
@@ -39,12 +40,14 @@ class CurlRequest;
 /**
  * Manager for the global CURLM object.
  */
-class CurlGlobal final : private TimeoutMonitor {
+class CurlGlobal final : TimeoutMonitor, DeferredMonitor {
 	CurlMulti multi;
 
 public:
 	explicit CurlGlobal(EventLoop &_loop);
 
+	using TimeoutMonitor::GetEventLoop;
+
 	void Add(CURL *easy, CurlRequest &request);
 	void Remove(CURL *easy);
 
@@ -76,9 +79,14 @@ public:
 	}
 
 private:
+	void UpdateTimeout(long timeout_ms);
 	static int TimerFunction(CURLM *global, long timeout_ms, void *userp);
 
-	virtual void OnTimeout() override;
+	/* virtual methods from class TimeoutMonitor */
+	void OnTimeout() override;
+
+	/* virtual methods from class DeferredMonitor */
+	void RunDeferred() override;
 };
 
 #endif

src/lib/curl/Multi.hxx

@@ -76,7 +76,7 @@ public:
 		return *this;
 	}
 
-	CURL *Get() {
+	CURLM *Get() {
 		return handle;
 	}
 

src/lib/curl/Request.cxx

@@ -46,7 +46,8 @@
 
 CurlRequest::CurlRequest(CurlGlobal &_global, const char *url,
 			 CurlResponseHandler &_handler)
-	:global(_global), handler(_handler)
+	:DeferredMonitor(_global.GetEventLoop()),
+	 global(_global), handler(_handler)
 {
 	error_buffer[0] = 0;
 
@@ -62,8 +63,6 @@ CurlRequest::CurlRequest(CurlGlobal &_global, const char *url,
 	easy.SetOption(CURLOPT_NOSIGNAL, 1l);
 	easy.SetOption(CURLOPT_CONNECTTIMEOUT, 10l);
 	easy.SetOption(CURLOPT_URL, url);
-
-	global.Add(easy.Get(), *this);
 }
 
 CurlRequest::~CurlRequest()
@@ -71,19 +70,40 @@ CurlRequest::~CurlRequest()
 	FreeEasy();
 }
 
+void
+CurlRequest::Start()
+{
+	assert(!registered);
+
+	global.Add(easy.Get(), *this);
+	registered = true;
+}
+
+void
+CurlRequest::Stop()
+{
+	if (!registered)
+		return;
+
+	global.Remove(easy.Get());
+	registered = false;
+}
+
 void
 CurlRequest::FreeEasy()
 {
 	if (!easy)
 		return;
 
-	global.Remove(easy.Get());
+	Stop();
 	easy = nullptr;
 }
 
 void
 CurlRequest::Resume()
 {
+	assert(registered);
+
 	curl_easy_pause(easy.Get(), CURLPAUSE_CONT);
 
 	if (IsCurlOlderThan(0x072000))
@@ -95,32 +115,24 @@ CurlRequest::Resume()
 	global.InvalidateSockets();
 }
 
-bool
+void
 CurlRequest::FinishHeaders()
 {
 	if (state != State::HEADERS)
-		return true;
+		return;
 
 	state = State::BODY;
 
 	long status = 0;
 	curl_easy_getinfo(easy.Get(), CURLINFO_RESPONSE_CODE, &status);
 
-	try {
-		handler.OnHeaders(status, std::move(headers));
-		return true;
-	} catch (...) {
-		state = State::CLOSED;
-		handler.OnError(std::current_exception());
-		return false;
-	}
+	handler.OnHeaders(status, std::move(headers));
 }
 
 void
 CurlRequest::FinishBody()
 {
-	if (!FinishHeaders())
-		return;
+	FinishHeaders();
 
 	if (state != State::BODY)
 		return;
@@ -132,7 +144,7 @@ CurlRequest::FinishBody()
 void
 CurlRequest::Done(CURLcode result)
 {
-	FreeEasy();
+	Stop();
 
 	try {
 		if (result != CURLE_OK) {
@@ -148,7 +160,12 @@ CurlRequest::Done(CURLcode result)
 		return;
 	}
 
-	FinishBody();
+	try {
+		FinishBody();
+	} catch (...) {
+		state = State::CLOSED;
+		handler.OnError(std::current_exception());
+	}
 }
 
 inline void
@@ -202,18 +219,19 @@ CurlRequest::DataReceived(const void *ptr, size_t received_size)
 {
 	assert(received_size > 0);
 
-	if (!FinishHeaders())
-		return 0;
-
 	try {
+		FinishHeaders();
 		handler.OnData({ptr, received_size});
 		return received_size;
 	} catch (Pause) {
 		return CURL_WRITEFUNC_PAUSE;
 	} catch (...) {
 		state = State::CLOSED;
-		handler.OnError(std::current_exception());
-		return 0;
+		/* move the CurlResponseHandler::OnError() call into a
+		   "safe" stack frame */
+		postponed_error = std::current_exception();
+		DeferredMonitor::Schedule();
+		return CURL_WRITEFUNC_PAUSE;
 	}
 
 }
@@ -229,3 +247,11 @@ CurlRequest::WriteFunction(void *ptr, size_t size, size_t nmemb, void *stream)
 
 	return c.DataReceived(ptr, size);
 }
+
+void
+CurlRequest::RunDeferred()
+{
+	assert(postponed_error);
+
+	handler.OnError(postponed_error);
+}

src/lib/curl/Request.hxx

@@ -31,15 +31,17 @@
 #define CURL_REQUEST_HXX
 
 #include "Easy.hxx"
+#include "event/DeferredMonitor.hxx"
 
 #include <map>
 #include <string>
+#include <exception>
 
 struct StringView;
 class CurlGlobal;
 class CurlResponseHandler;
 
-class CurlRequest {
+class CurlRequest final : DeferredMonitor {
 	CurlGlobal &global;
 
 	CurlResponseHandler &handler;
@@ -55,10 +57,25 @@ class CurlRequest {
 
 	std::multimap<std::string, std::string> headers;
 
+	/**
+	 * An exception caught by DataReceived(), which will be
+	 * forwarded into a "safe" stack frame by
+	 * DeferredMonitor::RunDeferred().  This works around the
+	 * problem that libcurl crashes if you call
+	 * curl_multi_remove_handle() from within the WRITEFUNCTION
+	 * (i.e. DataReceived()).
+	 */
+	std::exception_ptr postponed_error;
+
 	/** error message provided by libcurl */
 	char error_buffer[CURL_ERROR_SIZE];
 
+	bool registered = false;
+
 public:
+	/**
+	 * To start sending the request, call Start().
+	 */
 	CurlRequest(CurlGlobal &_global, const char *url,
 		    CurlResponseHandler &_handler);
 	~CurlRequest();
@@ -66,6 +83,21 @@ public:
 	CurlRequest(const CurlRequest &) = delete;
 	CurlRequest &operator=(const CurlRequest &) = delete;
 
+	/**
+	 * Register this request via CurlGlobal::Add(), which starts
+	 * the request.
+	 *
+	 * This method must be called in the event loop thread.
+	 */
+	void Start();
+
+	/**
+	 * Unregister this request via CurlGlobal::Remove().
+	 *
+	 * This method must be called in the event loop thread.
+	 */
+	void Stop();
+
 	CURL *Get() {
 		return easy.Get();
 	}
@@ -95,7 +127,7 @@ private:
 	 */
 	void FreeEasy();
 
-	bool FinishHeaders();
+	void FinishHeaders();
 	void FinishBody();
 
 	size_t DataReceived(const void *ptr, size_t size);
@@ -109,6 +141,9 @@ private:
 	/** called by curl when new data is available */
 	static size_t WriteFunction(void *ptr, size_t size, size_t nmemb,
 				    void *stream);
+
+	/* virtual methods from class DeferredMonitor */
+	void RunDeferred() override;
 };
 
 #endif

src/lib/curl/Slist.hxx

@@ -0,0 +1,76 @@
+/*
+ * Copyright (C) 2008-2017 Max Kellermann <max@duempel.org>
+ *
+ * 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 CURL_SLIST_HXX
+#define CURL_SLIST_HXX
+
+#include <curl/curl.h>
+
+#include <algorithm>
+
+/**
+ * OO wrapper for "struct curl_slist *".
+ */
+class CurlSlist {
+	struct curl_slist *head = nullptr;
+
+public:
+	CurlSlist() = default;
+
+	CurlSlist(CurlSlist &&src)
+		:head(std::exchange(src.head, nullptr)) {}
+
+	~CurlSlist() {
+		if (head != nullptr)
+			curl_slist_free_all(head);
+	}
+
+	CurlSlist &operator=(CurlSlist &&src) {
+		std::swap(head, src.head);
+		return *this;
+	}
+
+	struct curl_slist *Get() {
+		return head;
+	}
+
+	void Clear() {
+		curl_slist_free_all(head);
+		head = nullptr;
+	}
+
+	void Append(const char *value) {
+		auto *new_head = curl_slist_append(head, value);
+		if (new_head == nullptr)
+			throw std::runtime_error("curl_slist_append() failed");
+		head = new_head;
+	}
+};
+
+#endif

src/lib/expat/ExpatParser.cxx

@@ -19,7 +19,6 @@
 
 #include "config.h"
 #include "ExpatParser.hxx"
-#include "input/InputStream.hxx"
 #include "util/ASCII.hxx"
 
 #include <string.h>
@@ -31,23 +30,6 @@ ExpatParser::Parse(const char *data, size_t length, bool is_final)
 		throw ExpatError(parser);
 }
 
-void
-ExpatParser::Parse(InputStream &is)
-{
-	assert(is.IsReady());
-
-	while (true) {
-		char buffer[4096];
-		size_t nbytes = is.LockRead(buffer, sizeof(buffer));
-		if (nbytes == 0)
-			break;
-
-		Parse(buffer, nbytes, false);
-	}
-
-	Parse("", 0, true);
-}
-
 const char *
 ExpatParser::GetAttribute(const XML_Char **atts,
 			  const char *name)

src/lib/expat/ExpatParser.hxx

@@ -31,22 +31,31 @@ class InputStream;
 
 class ExpatError final : public std::runtime_error {
 public:
-	ExpatError(XML_Error code)
+	explicit ExpatError(XML_Error code)
 		:std::runtime_error(XML_ErrorString(code)) {}
 
-	ExpatError(XML_Parser parser)
+	explicit ExpatError(XML_Parser parser)
 		:ExpatError(XML_GetErrorCode(parser)) {}
 };
 
+struct ExpatNamespaceSeparator {
+	char separator;
+};
+
 class ExpatParser final {
 	const XML_Parser parser;
 
 public:
-	ExpatParser(void *userData)
+	explicit ExpatParser(void *userData)
 		:parser(XML_ParserCreate(nullptr)) {
 		XML_SetUserData(parser, userData);
 	}
 
+	ExpatParser(ExpatNamespaceSeparator ns, void *userData)
+		:parser(XML_ParserCreateNS(nullptr, ns.separator)) {
+		XML_SetUserData(parser, userData);
+	}
+
 	~ExpatParser() {
 		XML_ParserFree(parser);
 	}
@@ -89,6 +98,12 @@ public:
 		parser.SetCharacterDataHandler(CharacterData);
 	}
 
+	explicit CommonExpatParser(ExpatNamespaceSeparator ns)
+		:parser(ns, this) {
+		parser.SetElementHandler(StartElement, EndElement);
+		parser.SetCharacterDataHandler(CharacterData);
+	}
+
 	void Parse(const char *data, size_t length, bool is_final) {
 		parser.Parse(data, length, is_final);
 	}

src/lib/expat/StreamExpatParser.cxx

@@ -0,0 +1,39 @@
+/*
+ * Copyright 2003-2017 The Music Player Daemon Project
+ * http://www.musicpd.org
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include "config.h"
+#include "ExpatParser.hxx"
+#include "input/InputStream.hxx"
+
+void
+ExpatParser::Parse(InputStream &is)
+{
+	assert(is.IsReady());
+
+	while (true) {
+		char buffer[4096];
+		size_t nbytes = is.LockRead(buffer, sizeof(buffer));
+		if (nbytes == 0)
+			break;
+
+		Parse(buffer, nbytes, false);
+	}
+
+	Parse("", 0, true);
+}

src/mixer/plugins/AlsaMixerPlugin.cxx

@@ -25,15 +25,18 @@
 #include "event/DeferredMonitor.hxx"
 #include "util/ASCII.hxx"
 #include "util/ReusableArray.hxx"
-#include "util/Clamp.hxx"
 #include "util/Domain.hxx"
 #include "util/RuntimeError.hxx"
 #include "Log.hxx"
 
-#include <algorithm>
+extern "C" {
+#include "volume_mapping.h"
+}
 
 #include <alsa/asoundlib.h>
 
+#include <math.h>
+
 #define VOLUME_MIXER_ALSA_DEFAULT		"default"
 #define VOLUME_MIXER_ALSA_CONTROL_DEFAULT	"PCM"
 static constexpr unsigned VOLUME_MIXER_ALSA_INDEX_DEFAULT = 0;
@@ -68,9 +71,6 @@ class AlsaMixer final : public Mixer {
 
 	snd_mixer_t *handle;
 	snd_mixer_elem_t *elem;
-	long volume_min;
-	long volume_max;
-	int volume_set;
 
 	AlsaMixerMonitor *monitor;
 
@@ -228,9 +228,6 @@ AlsaMixer::Setup()
 	if (elem == nullptr)
 		throw FormatRuntimeError("no such mixer control: %s", control);
 
-	snd_mixer_selem_get_playback_volume_range(elem, &volume_min,
-						  &volume_max);
-
 	snd_mixer_elem_set_callback_private(elem, this);
 	snd_mixer_elem_set_callback(elem, alsa_mixer_elem_callback);
 
@@ -242,8 +239,6 @@ AlsaMixer::Open()
 {
 	int err;
 
-	volume_set = -1;
-
 	err = snd_mixer_open(&handle, 0);
 	if (err < 0)
 		throw FormatRuntimeError("snd_mixer_open() failed: %s",
@@ -272,8 +267,6 @@ int
 AlsaMixer::GetVolume()
 {
 	int err;
-	int ret;
-	long level;
 
 	assert(handle != nullptr);
 
@@ -282,43 +275,15 @@ AlsaMixer::GetVolume()
 		throw FormatRuntimeError("snd_mixer_handle_events() failed: %s",
 					 snd_strerror(err));
 
-	err = snd_mixer_selem_get_playback_volume(elem,
-						  SND_MIXER_SCHN_FRONT_LEFT,
-						  &level);
-	if (err < 0)
-		throw FormatRuntimeError("failed to read ALSA volume: %s",
-					 snd_strerror(err));
-
-	ret = ((volume_set / 100.0) * (volume_max - volume_min)
-	       + volume_min) + 0.5;
-	if (volume_set > 0 && ret == level) {
-		ret = volume_set;
-	} else {
-		ret = (int)(100 * (((float)(level - volume_min)) /
-				   (volume_max - volume_min)) + 0.5);
-	}
-
-	return ret;
+	return lrint(100 * get_normalized_playback_volume(elem, SND_MIXER_SCHN_FRONT_LEFT));
 }
 
 void
 AlsaMixer::SetVolume(unsigned volume)
 {
-	float vol;
-	long level;
-	int err;
-
 	assert(handle != nullptr);
 
-	vol = volume;
-
-	volume_set = vol + 0.5;
-
-	level = (long)(((vol / 100.0) * (volume_max - volume_min) +
-			volume_min) + 0.5);
-	level = Clamp(level, volume_min, volume_max);
-
-	err = snd_mixer_selem_set_playback_volume_all(elem, level);
+	int err = set_normalized_playback_volume(elem, 0.01*volume, 1);
 	if (err < 0)
 		throw FormatRuntimeError("failed to set ALSA volume: %s",
 					 snd_strerror(err));

src/mixer/plugins/volume_mapping.c

@@ -0,0 +1,180 @@
+/*
+ * Copyright (c) 2010 Clemens Ladisch <clemens@ladisch.de>
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+/*
+ * The functions in this file map the value ranges of ALSA mixer controls onto
+ * the interval 0..1.
+ *
+ * The mapping is designed so that the position in the interval is proportional
+ * to the volume as a human ear would perceive it (i.e., the position is the
+ * cubic root of the linear sample multiplication factor).  For controls with
+ * a small range (24 dB or less), the mapping is linear in the dB values so
+ * that each step has the same size visually.  Only for controls without dB
+ * information, a linear mapping of the hardware volume register values is used
+ * (this is the same algorithm as used in the old alsamixer).
+ *
+ * When setting the volume, 'dir' is the rounding direction:
+ * -1/0/1 = down/nearest/up.
+ */
+
+#include <math.h>
+#include <stdbool.h>
+#include "volume_mapping.h"
+
+#ifdef __UCLIBC__
+/* 10^x = 10^(log e^x) = (e^x)^log10 = e^(x * log 10) */
+#define exp10(x) (exp((x) * log(10)))
+#endif /* __UCLIBC__ */
+
+#define MAX_LINEAR_DB_SCALE	24
+
+static inline bool use_linear_dB_scale(long dBmin, long dBmax)
+{
+	return dBmax - dBmin <= MAX_LINEAR_DB_SCALE * 100;
+}
+
+static long lrint_dir(double x, int dir)
+{
+	if (dir > 0)
+		return lrint(ceil(x));
+	else if (dir < 0)
+		return lrint(floor(x));
+	else
+		return lrint(x);
+}
+
+enum ctl_dir { PLAYBACK, CAPTURE };
+
+static int (* const get_dB_range[2])(snd_mixer_elem_t *, long *, long *) = {
+	snd_mixer_selem_get_playback_dB_range,
+	snd_mixer_selem_get_capture_dB_range,
+};
+static int (* const get_raw_range[2])(snd_mixer_elem_t *, long *, long *) = {
+	snd_mixer_selem_get_playback_volume_range,
+	snd_mixer_selem_get_capture_volume_range,
+};
+static int (* const get_dB[2])(snd_mixer_elem_t *, snd_mixer_selem_channel_id_t, long *) = {
+	snd_mixer_selem_get_playback_dB,
+	snd_mixer_selem_get_capture_dB,
+};
+static int (* const get_raw[2])(snd_mixer_elem_t *, snd_mixer_selem_channel_id_t, long *) = {
+	snd_mixer_selem_get_playback_volume,
+	snd_mixer_selem_get_capture_volume,
+};
+static int (* const set_dB[2])(snd_mixer_elem_t *, long, int) = {
+	snd_mixer_selem_set_playback_dB_all,
+	snd_mixer_selem_set_capture_dB_all,
+};
+static int (* const set_raw[2])(snd_mixer_elem_t *, long) = {
+	snd_mixer_selem_set_playback_volume_all,
+	snd_mixer_selem_set_capture_volume_all,
+};
+
+static double get_normalized_volume(snd_mixer_elem_t *elem,
+				    snd_mixer_selem_channel_id_t channel,
+				    enum ctl_dir ctl_dir)
+{
+	long min, max, value;
+	double normalized, min_norm;
+	int err;
+
+	err = get_dB_range[ctl_dir](elem, &min, &max);
+	if (err < 0 || min >= max) {
+		err = get_raw_range[ctl_dir](elem, &min, &max);
+		if (err < 0 || min == max)
+			return 0;
+
+		err = get_raw[ctl_dir](elem, channel, &value);
+		if (err < 0)
+			return 0;
+
+		return (value - min) / (double)(max - min);
+	}
+
+	err = get_dB[ctl_dir](elem, channel, &value);
+	if (err < 0)
+		return 0;
+
+	if (use_linear_dB_scale(min, max))
+		return (value - min) / (double)(max - min);
+
+	normalized = exp10((value - max) / 6000.0);
+	if (min != SND_CTL_TLV_DB_GAIN_MUTE) {
+		min_norm = exp10((min - max) / 6000.0);
+		normalized = (normalized - min_norm) / (1 - min_norm);
+	}
+
+	return normalized;
+}
+
+static int set_normalized_volume(snd_mixer_elem_t *elem,
+				 double volume,
+				 int dir,
+				 enum ctl_dir ctl_dir)
+{
+	long min, max, value;
+	double min_norm;
+	int err;
+
+	err = get_dB_range[ctl_dir](elem, &min, &max);
+	if (err < 0 || min >= max) {
+		err = get_raw_range[ctl_dir](elem, &min, &max);
+		if (err < 0)
+			return err;
+
+		value = lrint_dir(volume * (max - min), dir) + min;
+		return set_raw[ctl_dir](elem, value);
+	}
+
+	if (use_linear_dB_scale(min, max)) {
+		value = lrint_dir(volume * (max - min), dir) + min;
+		return set_dB[ctl_dir](elem, value, dir);
+	}
+
+	if (min != SND_CTL_TLV_DB_GAIN_MUTE) {
+		min_norm = exp10((min - max) / 6000.0);
+		volume = volume * (1 - min_norm) + min_norm;
+	}
+	value = lrint_dir(6000.0 * log10(volume), dir) + max;
+	return set_dB[ctl_dir](elem, value, dir);
+}
+
+double get_normalized_playback_volume(snd_mixer_elem_t *elem,
+				      snd_mixer_selem_channel_id_t channel)
+{
+	return get_normalized_volume(elem, channel, PLAYBACK);
+}
+
+double get_normalized_capture_volume(snd_mixer_elem_t *elem,
+				     snd_mixer_selem_channel_id_t channel)
+{
+	return get_normalized_volume(elem, channel, CAPTURE);
+}
+
+
+int set_normalized_playback_volume(snd_mixer_elem_t *elem,
+				   double volume,
+				   int dir)
+{
+	return set_normalized_volume(elem, volume, dir, PLAYBACK);
+}
+
+int set_normalized_capture_volume(snd_mixer_elem_t *elem,
+				  double volume,
+				  int dir)
+{
+	return set_normalized_volume(elem, volume, dir, CAPTURE);
+}

src/mixer/plugins/volume_mapping.h

@@ -0,0 +1,17 @@
+#ifndef VOLUME_MAPPING_H_INCLUDED
+#define VOLUME_MAPPING_H_INCLUDED
+
+#include <alsa/asoundlib.h>
+
+double get_normalized_playback_volume(snd_mixer_elem_t *elem,
+				      snd_mixer_selem_channel_id_t channel);
+double get_normalized_capture_volume(snd_mixer_elem_t *elem,
+				     snd_mixer_selem_channel_id_t channel);
+int set_normalized_playback_volume(snd_mixer_elem_t *elem,
+				   double volume,
+				   int dir);
+int set_normalized_capture_volume(snd_mixer_elem_t *elem,
+				  double volume,
+				  int dir);
+
+#endif

src/storage/Registry.cxx

@@ -23,6 +23,7 @@
 #include "plugins/LocalStorage.hxx"
 #include "plugins/SmbclientStorage.hxx"
 #include "plugins/NfsStorage.hxx"
+#include "plugins/CurlStorage.hxx"
 
 #include <assert.h>
 #include <string.h>
@@ -34,6 +35,9 @@ const StoragePlugin *const storage_plugins[] = {
 #endif
 #ifdef ENABLE_NFS
 	&nfs_storage_plugin,
+#endif
+#ifdef ENABLE_WEBDAV
+	&curl_storage_plugin,
 #endif
 	nullptr
 };

src/storage/plugins/CurlStorage.cxx

@@ -0,0 +1,590 @@
+/*
+ * Copyright 2003-2016 The Music Player Daemon Project
+ * http://www.musicpd.org
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include "config.h"
+#include "CurlStorage.hxx"
+#include "storage/StoragePlugin.hxx"
+#include "storage/StorageInterface.hxx"
+#include "storage/FileInfo.hxx"
+#include "storage/MemoryDirectoryReader.hxx"
+#include "lib/curl/Global.hxx"
+#include "lib/curl/Slist.hxx"
+#include "lib/curl/Request.hxx"
+#include "lib/curl/Handler.hxx"
+#include "lib/expat/ExpatParser.hxx"
+#include "fs/Traits.hxx"
+#include "event/Call.hxx"
+#include "event/DeferredMonitor.hxx"
+#include "thread/Mutex.hxx"
+#include "thread/Cond.hxx"
+#include "util/RuntimeError.hxx"
+#include "util/StringCompare.hxx"
+#include "util/TimeParser.hxx"
+#include "util/UriUtil.hxx"
+
+#include <algorithm>
+#include <memory>
+#include <string>
+#include <list>
+
+#include <assert.h>
+
+class CurlStorage final : public Storage {
+	const std::string base;
+
+	CurlGlobal *const curl;
+
+public:
+	CurlStorage(EventLoop &_loop, const char *_base)
+		:base(_base),
+		 curl(new CurlGlobal(_loop)) {}
+
+	~CurlStorage() {
+		BlockingCall(curl->GetEventLoop(), [this](){ delete curl; });
+	}
+
+	/* virtual methods from class Storage */
+	StorageFileInfo GetInfo(const char *uri_utf8, bool follow) override;
+
+	StorageDirectoryReader *OpenDirectory(const char *uri_utf8) override;
+
+	std::string MapUTF8(const char *uri_utf8) const override;
+
+	const char *MapToRelativeUTF8(const char *uri_utf8) const override;
+};
+
+std::string
+CurlStorage::MapUTF8(const char *uri_utf8) const
+{
+	assert(uri_utf8 != nullptr);
+
+	if (StringIsEmpty(uri_utf8))
+		return base;
+
+	// TODO: escape the given URI
+
+	return PathTraitsUTF8::Build(base.c_str(), uri_utf8);
+}
+
+const char *
+CurlStorage::MapToRelativeUTF8(const char *uri_utf8) const
+{
+	// TODO: escape/unescape?
+
+	return PathTraitsUTF8::Relative(base.c_str(), uri_utf8);
+}
+
+class BlockingHttpRequest : protected CurlResponseHandler, DeferredMonitor {
+	std::exception_ptr postponed_error;
+
+	bool done = false;
+
+protected:
+	CurlRequest request;
+
+	Mutex mutex;
+	Cond cond;
+
+public:
+	BlockingHttpRequest(CurlGlobal &curl, const char *uri)
+		:DeferredMonitor(curl.GetEventLoop()),
+		 request(curl, uri, *this) {
+		// TODO: use CurlInputStream's configuration
+
+		/* start the transfer inside the IOThread */
+		DeferredMonitor::Schedule();
+	}
+
+	void Wait() {
+		const std::lock_guard<Mutex> lock(mutex);
+		while (!done)
+			cond.wait(mutex);
+
+		if (postponed_error)
+			std::rethrow_exception(postponed_error);
+	}
+
+protected:
+	void SetDone() {
+		assert(!done);
+
+		request.Stop();
+		done = true;
+		cond.signal();
+	}
+
+	void LockSetDone() {
+		const std::lock_guard<Mutex> lock(mutex);
+		SetDone();
+	}
+
+private:
+	/* virtual methods from DeferredMonitor */
+	void RunDeferred() final {
+		assert(!done);
+
+		request.Start();
+	}
+
+	/* virtual methods from CurlResponseHandler */
+	void OnError(std::exception_ptr e) final {
+		const std::lock_guard<Mutex> lock(mutex);
+		postponed_error = std::move(e);
+		SetDone();
+	}
+};
+
+/**
+ * A helper class which feeds a (foreign) memory buffer into the
+ * CURLOPT_READFUNCTION.
+ */
+class CurlRequestBody {
+	ConstBuffer<char> data;
+
+public:
+	explicit CurlRequestBody(ConstBuffer<void> _data)
+		:data(ConstBuffer<char>::FromVoid(_data)) {}
+
+	explicit constexpr CurlRequestBody(StringView _data)
+		:data(_data) {}
+
+	template<typename T>
+	CurlRequestBody(CurlRequest &request, T _data)
+		:CurlRequestBody(_data) {
+		request.SetOption(CURLOPT_READFUNCTION, Callback);
+		request.SetOption(CURLOPT_READDATA, this);
+	}
+
+private:
+	size_t Read(char *buffer, size_t size) {
+		size_t n = std::min(size, data.size);
+		std::copy_n(data.begin(), n, buffer);
+		return n;
+	}
+
+	static size_t Callback(char *buffer, size_t size, size_t nitems,
+			       void *instream) {
+		auto &rb = *(CurlRequestBody *)instream;
+		return rb.Read(buffer, size * nitems);
+	}
+};
+
+/**
+ * The (relevant) contents of a "<D:response>" element.
+ */
+struct DavResponse {
+	std::string href;
+	unsigned status = 0;
+	bool collection = false;
+	std::chrono::system_clock::time_point mtime =
+		std::chrono::system_clock::time_point::min();
+	uint64_t length = 0;
+
+	bool Check() const {
+		return !href.empty();
+	}
+};
+
+static unsigned
+ParseStatus(const char *s)
+{
+	/* skip the "HTTP/1.1" prefix */
+	const char *space = strchr(s, ' ');
+	if (space == nullptr)
+		return 0;
+
+	return strtoul(space + 1, nullptr, 10);
+}
+
+static unsigned
+ParseStatus(const char *s, size_t length)
+{
+	return ParseStatus(std::string(s, length).c_str());
+}
+
+static std::chrono::system_clock::time_point
+ParseTimeStamp(const char *s)
+{
+	try {
+		// TODO: make this more robust
+		return ParseTimePoint(s, "%a, %d %b %Y %T %Z");
+	} catch (const std::runtime_error &) {
+		return std::chrono::system_clock::time_point::min();
+	}
+}
+
+static std::chrono::system_clock::time_point
+ParseTimeStamp(const char *s, size_t length)
+{
+	return ParseTimeStamp(std::string(s, length).c_str());
+}
+
+static uint64_t
+ParseU64(const char *s)
+{
+	return strtoull(s, nullptr, 10);
+}
+
+static uint64_t
+ParseU64(const char *s, size_t length)
+{
+	return ParseU64(std::string(s, length).c_str());
+}
+
+/**
+ * A WebDAV PROPFIND request.  Each "response" element will be passed
+ * to OnDavResponse() (to be implemented by a derived class).
+ */
+class PropfindOperation : BlockingHttpRequest, CommonExpatParser {
+	CurlSlist request_headers;
+	CurlRequestBody request_body;
+
+	enum class State {
+		ROOT,
+		RESPONSE,
+		HREF,
+		STATUS,
+		TYPE,
+		MTIME,
+		LENGTH,
+	} state = State::ROOT;
+
+	DavResponse response;
+
+public:
+	PropfindOperation(CurlGlobal &_curl, const char *_uri, unsigned depth)
+		:BlockingHttpRequest(_curl, _uri),
+		 CommonExpatParser(ExpatNamespaceSeparator{'|'}),
+		 request_body(request,
+			      "<?xml version=\"1.0\"?>\n"
+			      "<a:propfind xmlns:a=\"DAV:\">"
+			      "<a:prop><a:getcontenttype/></a:prop>"
+			      "<a:prop><a:getcontentlength/></a:prop>"
+			      "</a:propfind>")
+	{
+		request.SetOption(CURLOPT_CUSTOMREQUEST, "PROPFIND");
+
+		char buffer[40];
+		sprintf(buffer, "depth: %u", depth);
+		request_headers.Append(buffer);
+
+		request.SetOption(CURLOPT_HTTPHEADER, request_headers.Get());
+
+		// TODO: send request body
+	}
+
+	using BlockingHttpRequest::Wait;
+
+protected:
+	virtual void OnDavResponse(DavResponse &&r) = 0;
+
+private:
+	void FinishResponse() {
+		if (response.Check())
+			OnDavResponse(std::move(response));
+		response = DavResponse();
+	}
+
+	/* virtual methods from CurlResponseHandler */
+	void OnHeaders(unsigned status,
+		       std::multimap<std::string, std::string> &&headers) final {
+		if (status != 207)
+			throw FormatRuntimeError("Status %d from WebDAV server; expected \"207 Multi-Status\"",
+						 status);
+
+		auto i = headers.find("content-type");
+		if (i == headers.end() ||
+		    strncmp(i->second.c_str(), "text/xml", 8) != 0)
+			throw std::runtime_error("Unexpected Content-Type from WebDAV server");
+	}
+
+	void OnData(ConstBuffer<void> _data) final {
+		const auto data = ConstBuffer<char>::FromVoid(_data);
+		Parse(data.data, data.size, false);
+	}
+
+	void OnEnd() final {
+		Parse("", 0, true);
+		LockSetDone();
+	}
+
+	/* virtual methods from CommonExpatParser */
+	void StartElement(const XML_Char *name,
+			  gcc_unused const XML_Char **attrs) final {
+		switch (state) {
+		case State::ROOT:
+			if (strcmp(name, "DAV:|response") == 0)
+				state = State::RESPONSE;
+			break;
+
+		case State::RESPONSE:
+			if (strcmp(name, "DAV:|href") == 0)
+				state = State::HREF;
+			else if (strcmp(name, "DAV:|status") == 0)
+				state = State::STATUS;
+			else if (strcmp(name, "DAV:|resourcetype") == 0)
+				state = State::TYPE;
+			else if (strcmp(name, "DAV:|getlastmodified") == 0)
+				state = State::MTIME;
+			else if (strcmp(name, "DAV:|getcontentlength") == 0)
+				state = State::LENGTH;
+			break;
+
+		case State::TYPE:
+			if (strcmp(name, "DAV:|collection") == 0)
+				response.collection = true;
+			break;
+
+		case State::HREF:
+		case State::STATUS:
+		case State::LENGTH:
+		case State::MTIME:
+			break;
+		}
+	}
+
+	void EndElement(const XML_Char *name) final {
+		switch (state) {
+		case State::ROOT:
+			break;
+
+		case State::RESPONSE:
+			if (strcmp(name, "DAV:|response") == 0) {
+				FinishResponse();
+				state = State::ROOT;
+			}
+
+			break;
+
+		case State::HREF:
+			if (strcmp(name, "DAV:|href") == 0)
+				state = State::RESPONSE;
+			break;
+
+		case State::STATUS:
+			if (strcmp(name, "DAV:|status") == 0)
+				state = State::RESPONSE;
+			break;
+
+		case State::TYPE:
+			if (strcmp(name, "DAV:|resourcetype") == 0)
+				state = State::RESPONSE;
+			break;
+
+		case State::MTIME:
+			if (strcmp(name, "DAV:|getlastmodified") == 0)
+				state = State::RESPONSE;
+			break;
+
+		case State::LENGTH:
+			if (strcmp(name, "DAV:|getcontentlength") == 0)
+				state = State::RESPONSE;
+			break;
+		}
+	}
+
+	void CharacterData(const XML_Char *s, int len) final {
+		switch (state) {
+		case State::ROOT:
+		case State::RESPONSE:
+		case State::TYPE:
+			break;
+
+		case State::HREF:
+			response.href.assign(s, len);
+			break;
+
+		case State::STATUS:
+			response.status = ParseStatus(s, len);
+			break;
+
+		case State::MTIME:
+			response.mtime = ParseTimeStamp(s, len);
+			break;
+
+		case State::LENGTH:
+			response.length = ParseU64(s, len);
+			break;
+		}
+	}
+};
+
+/**
+ * Obtain information about a single file using WebDAV PROPFIND.
+ */
+class HttpGetInfoOperation final : public PropfindOperation {
+	StorageFileInfo info;
+
+public:
+	HttpGetInfoOperation(CurlGlobal &curl, const char *uri)
+		:PropfindOperation(curl, uri, 0) {
+		info.type = StorageFileInfo::Type::OTHER;
+		info.size = 0;
+		info.mtime = 0;
+		info.device = info.inode = 0;
+	}
+
+	const StorageFileInfo &Perform() {
+		Wait();
+		return info;
+	}
+
+protected:
+	/* virtual methods from PropfindOperation */
+	void OnDavResponse(DavResponse &&r) override {
+		if (r.status != 200)
+			return;
+
+		info.type = r.collection
+			? StorageFileInfo::Type::DIRECTORY
+			: StorageFileInfo::Type::REGULAR;
+		info.size = r.length;
+		info.mtime = r.mtime > std::chrono::system_clock::time_point()
+			? std::chrono::system_clock::to_time_t(r.mtime)
+			: 0;
+		info.device = info.inode = 0;
+	}
+};
+
+StorageFileInfo
+CurlStorage::GetInfo(const char *uri_utf8, gcc_unused bool follow)
+{
+	// TODO: escape the given URI
+
+	std::string uri = base;
+	uri += uri_utf8;
+
+	return HttpGetInfoOperation(*curl, uri.c_str()).Perform();
+}
+
+gcc_pure
+static const char *
+UriPathOrSlash(const char *uri)
+{
+	const char *path = uri_get_path(uri);
+	if (path == nullptr)
+		path = "/";
+	return path;
+}
+
+/**
+ * Obtain a directory listing using WebDAV PROPFIND.
+ */
+class HttpListDirectoryOperation final : public PropfindOperation {
+	const std::string base_path;
+
+	MemoryStorageDirectoryReader::List entries;
+
+public:
+	HttpListDirectoryOperation(CurlGlobal &curl, const char *uri)
+		:PropfindOperation(curl, uri, 1),
+		 base_path(UriPathOrSlash(uri)) {}
+
+	StorageDirectoryReader *Perform() {
+		Wait();
+		return ToReader();
+	}
+
+private:
+	StorageDirectoryReader *ToReader() {
+		return new MemoryStorageDirectoryReader(std::move(entries));
+	}
+
+	/**
+	 * Convert a "href" attribute (which may be an absolute URI)
+	 * to the base file name.
+	 */
+	gcc_pure
+	StringView HrefToEscapedName(const char *href) const {
+		const char *path = uri_get_path(href);
+		if (path == nullptr)
+			return nullptr;
+
+		path = StringAfterPrefix(path, base_path.c_str());
+		if (path == nullptr || *path == 0)
+			return nullptr;
+
+		const char *slash = strchr(path, '/');
+		if (slash == nullptr)
+			/* regular file */
+			return path;
+		else if (slash[1] == 0)
+			/* trailing slash: collection; strip the slash */
+			return {path, slash};
+		else
+			/* strange, better ignore it */
+			return nullptr;
+	}
+
+protected:
+	/* virtual methods from PropfindOperation */
+	void OnDavResponse(DavResponse &&r) override {
+		if (r.status != 200)
+			return;
+
+		const auto escaped_name = HrefToEscapedName(r.href.c_str());
+		if (escaped_name.IsNull())
+			return;
+
+		// TODO: unescape
+		const auto name = escaped_name;
+
+		entries.emplace_front(std::string(name.data, name.size));
+
+		auto &info = entries.front().info;
+		info.type = r.collection
+			? StorageFileInfo::Type::DIRECTORY
+			: StorageFileInfo::Type::REGULAR;
+		info.size = r.length;
+		info.mtime = r.mtime > std::chrono::system_clock::time_point()
+			? std::chrono::system_clock::to_time_t(r.mtime)
+			: 0;
+		info.device = info.inode = 0;
+	}
+};
+
+StorageDirectoryReader *
+CurlStorage::OpenDirectory(const char *uri_utf8)
+{
+	// TODO: escape the given URI
+
+	std::string uri = base;
+	uri += uri_utf8;
+
+	/* collection URIs must end with a slash */
+	if (uri.back() != '/')
+		uri.push_back('/');
+
+	return HttpListDirectoryOperation(*curl, uri.c_str()).Perform();
+}
+
+static Storage *
+CreateCurlStorageURI(EventLoop &event_loop, const char *uri)
+{
+	if (strncmp(uri, "http://", 7) != 0 &&
+	    strncmp(uri, "https://", 8) != 0)
+		return nullptr;
+
+	return new CurlStorage(event_loop, uri);
+}
+
+const StoragePlugin curl_storage_plugin = {
+	"curl",
+	CreateCurlStorageURI,
+};

src/storage/plugins/CurlStorage.hxx

@@ -0,0 +1,29 @@
+/*
+ * Copyright 2003-2016 The Music Player Daemon Project
+ * http://www.musicpd.org
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#ifndef MPD_STORAGE_CURL_HXX
+#define MPD_STORAGE_CURL_HXX
+
+#include "check.h"
+
+struct StoragePlugin;
+
+extern const StoragePlugin curl_storage_plugin;
+
+#endif

src/util/TimeParser.cxx

@@ -0,0 +1,81 @@
+/*
+ * Copyright (C) 2014-2017 Max Kellermann <max@duempel.org>
+ *
+ * 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 "TimeParser.hxx"
+
+#include <stdexcept>
+
+#include <assert.h>
+#include <time.h>
+
+#if !defined(__GLIBC__) && !defined(WIN32)
+
+/**
+ * Determine the time zone offset in a portable way.
+ */
+gcc_const
+static time_t
+GetTimeZoneOffset()
+{
+	time_t t = 1234567890;
+	struct tm tm;
+	tm.tm_isdst = 0;
+	gmtime_r(&t, &tm);
+	return t - mktime(&tm);
+}
+
+#endif
+
+std::chrono::system_clock::time_point
+ParseTimePoint(const char *s, const char *format)
+{
+	assert(s != nullptr);
+	assert(format != nullptr);
+
+#ifdef WIN32
+	/* TODO: emulate strptime()? */
+	throw std::runtime_error("Time parsing not implemented on Windows");
+#else
+	struct tm tm;
+	const char *end = strptime(s, format, &tm);
+	if (end == nullptr || *end != 0)
+		throw std::runtime_error("Failed to parse time stamp");
+
+#ifdef __GLIBC__
+	/* timegm() is a GNU extension */
+	const auto t = timegm(&tm);
+#else
+	tm.tm_isdst = 0;
+	const auto t = mktime(&tm) + GetTimeZoneOffset();
+#endif /* !__GLIBC__ */
+
+	return std::chrono::system_clock::from_time_t(t);
+
+#endif /* !WIN32 */
+}

src/util/TimeParser.hxx

@@ -0,0 +1,46 @@
+/*
+ * Copyright (C) 2014-2017 Max Kellermann <max@duempel.org>
+ *
+ * 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 TIME_PARSER_HXX
+#define TIME_PARSER_HXX
+
+#include "Compiler.h"
+
+#include <chrono>
+
+/**
+ * Parse a time stamp.
+ *
+ * Throws std::runtime_error on error.
+ */
+gcc_pure
+std::chrono::system_clock::time_point
+ParseTimePoint(const char *s, const char *format);
+
+#endif

src/util/UriUtil.cxx

@@ -19,10 +19,57 @@
 
 #include "UriUtil.hxx"
 #include "StringCompare.hxx"
+#include "CharUtil.hxx"
 
 #include <assert.h>
 #include <string.h>
 
+static constexpr bool
+IsValidSchemeStart(char ch)
+{
+	return IsLowerAlphaASCII(ch);
+}
+
+static constexpr bool
+IsValidSchemeChar(char ch)
+{
+	return IsLowerAlphaASCII(ch) || IsDigitASCII(ch) ||
+		ch == '+' || ch == '.' || ch == '-';
+}
+
+gcc_pure
+static bool
+IsValidScheme(StringView p)
+{
+	if (p.IsEmpty() || !IsValidSchemeStart(p.front()))
+		return false;
+
+	for (size_t i = 1; i < p.size; ++i)
+		if (!IsValidSchemeChar(p[i]))
+			return false;
+
+	return true;
+}
+
+/**
+ * Return the URI part after the scheme specification (and after the
+ * double slash).
+ */
+gcc_pure
+static const char *
+uri_after_scheme(const char *uri)
+{
+	if (uri[0] == '/' && uri[1] == '/' && uri[2] != '/')
+		return uri + 2;
+
+	const char *colon = strchr(uri, ':');
+	return colon != nullptr &&
+		IsValidScheme({uri, colon}) &&
+		colon[1] == '/' && colon[2] == '/'
+		? colon + 3
+		: nullptr;
+}
+
 bool uri_has_scheme(const char *uri)
 {
 	return strstr(uri, "://") != nullptr;
@@ -38,6 +85,16 @@ uri_get_scheme(const char *uri)
 	return std::string(uri, end);
 }
 
+const char *
+uri_get_path(const char *uri)
+{
+	const char *ap = uri_after_scheme(uri);
+	if (ap != nullptr)
+		return strchr(ap, '/');
+
+	return uri;
+}
+
 /* suffixes should be ascii only characters */
 const char *
 uri_get_suffix(const char *uri)

src/util/UriUtil.hxx

@@ -38,6 +38,14 @@ gcc_pure
 std::string
 uri_get_scheme(const char *uri);
 
+/**
+ * Returns the URI path (including the query string) or nullptr if the
+ * given URI has no path.
+ */
+gcc_pure gcc_nonnull_all
+const char *
+uri_get_path(const char *uri);
+
 gcc_pure
 const char *
 uri_get_suffix(const char *uri);

test/run_storage.cxx

@@ -67,8 +67,13 @@ Ls(Storage &storage, const char *path)
 			break;
 		}
 
-		char mtime[32];
-		strftime(mtime, sizeof(mtime), "%F", gmtime(&info.mtime));
+		char mtime_buffer[32];
+		const char *mtime = "          ";
+		if (info.mtime > 0) {
+			strftime(mtime_buffer, sizeof(mtime_buffer), "%F",
+				 gmtime(&info.mtime));
+			mtime = mtime_buffer;
+		}
 
 		printf("%s %10llu %s %s\n",
 		       type, (unsigned long long)info.size,