Input*: move to input/

1 files changed, 1170 insertions, 0 deletions

diff --git a/src/input/plugins/CurlInputPlugin.cxx b/src/input/plugins/CurlInputPlugin.cxx
new file mode 100644
index 000000000..a3c6c1d1a
--- /dev/null
+++ b/src/input/plugins/CurlInputPlugin.cxx
@@ -0,0 +1,1170 @@
+/*
+ * Copyright (C) 2003-2014 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 "CurlInputPlugin.hxx"
+#include "../InputStream.hxx"
+#include "../InputPlugin.hxx"
+#include "config/ConfigGlobal.hxx"
+#include "config/ConfigData.hxx"
+#include "tag/Tag.hxx"
+#include "tag/TagBuilder.hxx"
+#include "IcyMetaDataParser.hxx"
+#include "event/SocketMonitor.hxx"
+#include "event/TimeoutMonitor.hxx"
+#include "event/Call.hxx"
+#include "IOThread.hxx"
+#include "util/ASCII.hxx"
+#include "util/CharUtil.hxx"
+#include "util/NumberParser.hxx"
+#include "util/Error.hxx"
+#include "util/Domain.hxx"
+#include "Log.hxx"
+
+#include <assert.h>
+
+#if defined(WIN32)
+	#include <winsock2.h>
+#else
+	#include <sys/select.h>
+#endif
+
+#include <string.h>
+#include <errno.h>
+
+#include <list>
+
+#include <curl/curl.h>
+#include <glib.h>
+
+#if LIBCURL_VERSION_NUM < 0x071200
+#error libcurl is too old
+#endif
+
+/**
+ * Do not buffer more than this number of bytes.  It should be a
+ * reasonable limit that doesn't make low-end machines suffer too
+ * much, but doesn't cause stuttering on high-latency lines.
+ */
+static const size_t CURL_MAX_BUFFERED = 512 * 1024;
+
+/**
+ * Resume the stream at this number of bytes after it has been paused.
+ */
+static const size_t CURL_RESUME_AT = 384 * 1024;
+
+/**
+ * Buffers created by input_curl_writefunction().
+ */
+class CurlInputBuffer {
+	/** size of the payload */
+	size_t size;
+
+	/** how much has been consumed yet? */
+	size_t consumed;
+
+	/** the payload */
+	uint8_t *data;
+
+public:
+	CurlInputBuffer(const void *_data, size_t _size)
+		:size(_size), consumed(0), data(new uint8_t[size]) {
+		memcpy(data, _data, size);
+	}
+
+	~CurlInputBuffer() {
+		delete[] data;
+	}
+
+	CurlInputBuffer(const CurlInputBuffer &) = delete;
+	CurlInputBuffer &operator=(const CurlInputBuffer &) = delete;
+
+	const void *Begin() const {
+		return data + consumed;
+	}
+
+	size_t TotalSize() const {
+		return size;
+	}
+
+	size_t Available() const {
+		return size - consumed;
+	}
+
+	/**
+	 * Mark a part of the buffer as consumed.
+	 *
+	 * @return false if the buffer is now empty
+	 */
+	bool Consume(size_t length) {
+		assert(consumed < size);
+
+		consumed += length;
+		if (consumed < size)
+			return true;
+
+		assert(consumed == size);
+		return false;
+	}
+
+	bool Read(void *dest, size_t length) {
+		assert(consumed + length <= size);
+
+		memcpy(dest, data + consumed, length);
+		return Consume(length);
+	}
+};
+
+struct input_curl {
+	InputStream base;
+
+	/* some buffers which were passed to libcurl, which we have
+	   too free */
+	char range[32];
+	struct curl_slist *request_headers;
+
+	/** the curl handles */
+	CURL *easy;
+
+	/** list of buffers, where input_curl_writefunction() appends
+	    to, and input_curl_read() reads from them */
+	std::list<CurlInputBuffer> buffers;
+
+	/**
+	 * Is the connection currently paused?  That happens when the
+	 * buffer was getting too large.  It will be unpaused when the
+	 * buffer is below the threshold again.
+	 */
+	bool paused;
+
+	/** error message provided by libcurl */
+	char error[CURL_ERROR_SIZE];
+
+	/** parser for icy-metadata */
+	IcyMetaDataParser icy;
+
+	/** the stream name from the icy-name response header */
+	std::string meta_name;
+
+	/** the tag object ready to be requested via
+	    InputStream::ReadTag() */
+	Tag *tag;
+
+	Error postponed_error;
+
+	input_curl(const char *url, Mutex &mutex, Cond &cond)
+		:base(input_plugin_curl, url, mutex, cond),
+		 request_headers(nullptr),
+		 paused(false),
+		 tag(nullptr) {}
+
+	~input_curl();
+
+	input_curl(const input_curl &) = delete;
+	input_curl &operator=(const input_curl &) = delete;
+};
+
+class CurlMulti;
+
+/**
+ * Monitor for one socket created by CURL.
+ */
+class CurlSocket final : SocketMonitor {
+	CurlMulti &multi;
+
+public:
+	CurlSocket(CurlMulti &_multi, EventLoop &_loop, int _fd)
+		:SocketMonitor(_fd, _loop), multi(_multi) {}
+
+	~CurlSocket() {
+		/* TODO: sometimes, CURL uses CURL_POLL_REMOVE after
+		   closing the socket, and sometimes, it uses
+		   CURL_POLL_REMOVE just to move the (still open)
+		   connection to the pool; in the first case,
+		   Abandon() would be most appropriate, but it breaks
+		   the second case - is that a CURL bug?  is there a
+		   better solution? */
+	}
+
+	/**
+	 * Callback function for CURLMOPT_SOCKETFUNCTION.
+	 */
+	static int SocketFunction(CURL *easy,
+				  curl_socket_t s, int action,
+				  void *userp, void *socketp);
+
+	virtual bool OnSocketReady(unsigned flags) override;
+
+private:
+	static constexpr int FlagsToCurlCSelect(unsigned flags) {
+		return (flags & (READ | HANGUP) ? CURL_CSELECT_IN : 0) |
+			(flags & WRITE ? CURL_CSELECT_OUT : 0) |
+			(flags & ERROR ? CURL_CSELECT_ERR : 0);
+	}
+
+	gcc_const
+	static unsigned CurlPollToFlags(int action) {
+		switch (action) {
+		case CURL_POLL_NONE:
+			return 0;
+
+		case CURL_POLL_IN:
+			return READ;
+
+		case CURL_POLL_OUT:
+			return WRITE;
+
+		case CURL_POLL_INOUT:
+			return READ|WRITE;
+		}
+
+		assert(false);
+		gcc_unreachable();
+	}
+};
+
+/**
+ * Manager for the global CURLM object.
+ */
+class CurlMulti final : private TimeoutMonitor {
+	CURLM *const multi;
+
+public:
+	CurlMulti(EventLoop &_loop, CURLM *_multi);
+
+	~CurlMulti() {
+		curl_multi_cleanup(multi);
+	}
+
+	bool Add(input_curl *c, Error &error);
+	void Remove(input_curl *c);
+
+	/**
+	 * Check for finished HTTP responses.
+	 *
+	 * Runs in the I/O thread.  The caller must not hold locks.
+	 */
+	void ReadInfo();
+
+	void Assign(curl_socket_t fd, CurlSocket &cs) {
+		curl_multi_assign(multi, fd, &cs);
+	}
+
+	void SocketAction(curl_socket_t fd, int ev_bitmask);
+
+	void InvalidateSockets() {
+		SocketAction(CURL_SOCKET_TIMEOUT, 0);
+	}
+
+	/**
+	 * This is a kludge to allow pausing/resuming a stream with
+	 * libcurl < 7.32.0.  Read the curl_easy_pause manpage for
+	 * more information.
+	 */
+	void ResumeSockets() {
+		int running_handles;
+		curl_multi_socket_all(multi, &running_handles);
+	}
+
+private:
+	static int TimerFunction(CURLM *multi, long timeout_ms, void *userp);
+
+	virtual void OnTimeout() override;
+};
+
+/**
+ * libcurl version number encoded in a 24 bit integer.
+ */
+static unsigned curl_version_num;
+
+/** libcurl should accept "ICY 200 OK" */
+static struct curl_slist *http_200_aliases;
+
+/** HTTP proxy settings */
+static const char *proxy, *proxy_user, *proxy_password;
+static unsigned proxy_port;
+
+static CurlMulti *curl_multi;
+
+static constexpr Domain http_domain("http");
+static constexpr Domain curl_domain("curl");
+static constexpr Domain curlm_domain("curlm");
+
+CurlMulti::CurlMulti(EventLoop &_loop, CURLM *_multi)
+	:TimeoutMonitor(_loop), multi(_multi)
+{
+	curl_multi_setopt(multi, CURLMOPT_SOCKETFUNCTION,
+			  CurlSocket::SocketFunction);
+	curl_multi_setopt(multi, CURLMOPT_SOCKETDATA, this);
+
+	curl_multi_setopt(multi, CURLMOPT_TIMERFUNCTION, TimerFunction);
+	curl_multi_setopt(multi, CURLMOPT_TIMERDATA, this);
+}
+
+/**
+ * Find a request by its CURL "easy" handle.
+ *
+ * Runs in the I/O thread.  No lock needed.
+ */
+gcc_pure
+static struct input_curl *
+input_curl_find_request(CURL *easy)
+{
+	assert(io_thread_inside());
+
+	void *p;
+	CURLcode code = curl_easy_getinfo(easy, CURLINFO_PRIVATE, &p);
+	if (code != CURLE_OK)
+		return nullptr;
+
+	return (input_curl *)p;
+}
+
+static void
+input_curl_resume(struct input_curl *c)
+{
+	assert(io_thread_inside());
+
+	if (c->paused) {
+		c->paused = false;
+		curl_easy_pause(c->easy, CURLPAUSE_CONT);
+
+		if (curl_version_num < 0x072000)
+			/* libcurl older than 7.32.0 does not update
+			   its sockets after curl_easy_pause(); force
+			   libcurl to do it now */
+			curl_multi->ResumeSockets();
+
+		curl_multi->InvalidateSockets();
+	}
+}
+
+int
+CurlSocket::SocketFunction(gcc_unused CURL *easy,
+			   curl_socket_t s, int action,
+			   void *userp, void *socketp) {
+	CurlMulti &multi = *(CurlMulti *)userp;
+	CurlSocket *cs = (CurlSocket *)socketp;
+
+	assert(io_thread_inside());
+
+	if (action == CURL_POLL_REMOVE) {
+		delete cs;
+		return 0;
+	}
+
+	if (cs == nullptr) {
+		cs = new CurlSocket(multi, io_thread_get(), s);
+		multi.Assign(s, *cs);
+	} else {
+#ifdef USE_EPOLL
+		/* when using epoll, we need to unregister the socket
+		   each time this callback is invoked, because older
+		   CURL versions may omit the CURL_POLL_REMOVE call
+		   when the socket has been closed and recreated with
+		   the same file number (bug found in CURL 7.26, CURL
+		   7.33 not affected); in that case, epoll refuses the
+		   EPOLL_CTL_MOD because it does not know the new
+		   socket yet */
+		cs->Cancel();
+#endif
+	}
+
+	unsigned flags = CurlPollToFlags(action);
+	if (flags != 0)
+		cs->Schedule(flags);
+	return 0;
+}
+
+bool
+CurlSocket::OnSocketReady(unsigned flags)
+{
+	assert(io_thread_inside());
+
+	multi.SocketAction(Get(), FlagsToCurlCSelect(flags));
+	return true;
+}
+
+/**
+ * Runs in the I/O thread.  No lock needed.
+ */
+inline bool
+CurlMulti::Add(struct input_curl *c, Error &error)
+{
+	assert(io_thread_inside());
+	assert(c != nullptr);
+	assert(c->easy != nullptr);
+
+	CURLMcode mcode = curl_multi_add_handle(multi, c->easy);
+	if (mcode != CURLM_OK) {
+		error.Format(curlm_domain, mcode,
+			     "curl_multi_add_handle() failed: %s",
+			     curl_multi_strerror(mcode));
+		return false;
+	}
+
+	InvalidateSockets();
+	return true;
+}
+
+/**
+ * Call input_curl_easy_add() in the I/O thread.  May be called from
+ * any thread.  Caller must not hold a mutex.
+ */
+static bool
+input_curl_easy_add_indirect(struct input_curl *c, Error &error)
+{
+	assert(c != nullptr);
+	assert(c->easy != nullptr);
+
+	bool result;
+	BlockingCall(io_thread_get(), [c, &error, &result](){
+			result = curl_multi->Add(c, error);
+		});
+	return result;
+}
+
+inline void
+CurlMulti::Remove(input_curl *c)
+{
+	curl_multi_remove_handle(multi, c->easy);
+}
+
+/**
+ * Frees the current "libcurl easy" handle, and everything associated
+ * with it.
+ *
+ * Runs in the I/O thread.
+ */
+static void
+input_curl_easy_free(struct input_curl *c)
+{
+	assert(io_thread_inside());
+	assert(c != nullptr);
+
+	if (c->easy == nullptr)
+		return;
+
+	curl_multi->Remove(c);
+
+	curl_easy_cleanup(c->easy);
+	c->easy = nullptr;
+
+	curl_slist_free_all(c->request_headers);
+	c->request_headers = nullptr;
+}
+
+/**
+ * Frees the current "libcurl easy" handle, and everything associated
+ * with it.
+ *
+ * The mutex must not be locked.
+ */
+static void
+input_curl_easy_free_indirect(struct input_curl *c)
+{
+	BlockingCall(io_thread_get(), [c](){
+			input_curl_easy_free(c);
+			curl_multi->InvalidateSockets();
+		});
+
+	assert(c->easy == nullptr);
+}
+
+/**
+ * A HTTP request is finished.
+ *
+ * Runs in the I/O thread.  The caller must not hold locks.
+ */
+static void
+input_curl_request_done(struct input_curl *c, CURLcode result, long status)
+{
+	assert(io_thread_inside());
+	assert(c != nullptr);
+	assert(c->easy == nullptr);
+	assert(!c->postponed_error.IsDefined());
+
+	const ScopeLock protect(c->base.mutex);
+
+	if (result != CURLE_OK) {
+		c->postponed_error.Format(curl_domain, result,
+					  "curl failed: %s", c->error);
+	} else if (status < 200 || status >= 300) {
+		c->postponed_error.Format(http_domain, status,
+					  "got HTTP status %ld",
+					  status);
+	}
+
+	c->base.ready = true;
+
+	c->base.cond.broadcast();
+}
+
+static void
+input_curl_handle_done(CURL *easy_handle, CURLcode result)
+{
+	struct input_curl *c = input_curl_find_request(easy_handle);
+	assert(c != nullptr);
+
+	long status = 0;
+	curl_easy_getinfo(easy_handle, CURLINFO_RESPONSE_CODE, &status);
+
+	input_curl_easy_free(c);
+	input_curl_request_done(c, result, status);
+}
+
+void
+CurlMulti::SocketAction(curl_socket_t fd, int ev_bitmask)
+{
+	int running_handles;
+	CURLMcode mcode = curl_multi_socket_action(multi, fd, ev_bitmask,
+						   &running_handles);
+	if (mcode != CURLM_OK)
+		FormatError(curlm_domain,
+			    "curl_multi_socket_action() failed: %s",
+			    curl_multi_strerror(mcode));
+
+	ReadInfo();
+}
+
+/**
+ * Check for finished HTTP responses.
+ *
+ * Runs in the I/O thread.  The caller must not hold locks.
+ */
+inline void
+CurlMulti::ReadInfo()
+{
+	assert(io_thread_inside());
+
+	CURLMsg *msg;
+	int msgs_in_queue;
+
+	while ((msg = curl_multi_info_read(multi,
+					   &msgs_in_queue)) != nullptr) {
+		if (msg->msg == CURLMSG_DONE)
+			input_curl_handle_done(msg->easy_handle, msg->data.result);
+	}
+}
+
+int
+CurlMulti::TimerFunction(gcc_unused CURLM *_multi, long timeout_ms, void *userp)
+{
+	CurlMulti &multi = *(CurlMulti *)userp;
+	assert(_multi == multi.multi);
+
+	if (timeout_ms < 0) {
+		multi.Cancel();
+		return 0;
+	}
+
+	if (timeout_ms >= 0 && 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;
+
+	multi.Schedule(timeout_ms);
+	return 0;
+}
+
+void
+CurlMulti::OnTimeout()
+{
+	SocketAction(CURL_SOCKET_TIMEOUT, 0);
+}
+
+/*
+ * InputPlugin methods
+ *
+ */
+
+static bool
+input_curl_init(const config_param &param, Error &error)
+{
+	CURLcode code = curl_global_init(CURL_GLOBAL_ALL);
+	if (code != CURLE_OK) {
+		error.Format(curl_domain, code,
+			     "curl_global_init() failed: %s",
+			     curl_easy_strerror(code));
+		return false;
+	}
+
+	const auto version_info = curl_version_info(CURLVERSION_FIRST);
+	if (version_info != nullptr) {
+		FormatDebug(curl_domain, "version %s", version_info->version);
+		if (version_info->features & CURL_VERSION_SSL)
+			FormatDebug(curl_domain, "with %s",
+				    version_info->ssl_version);
+
+		curl_version_num = version_info->version_num;
+	}
+
+	http_200_aliases = curl_slist_append(http_200_aliases, "ICY 200 OK");
+
+	proxy = param.GetBlockValue("proxy");
+	proxy_port = param.GetBlockValue("proxy_port", 0u);
+	proxy_user = param.GetBlockValue("proxy_user");
+	proxy_password = param.GetBlockValue("proxy_password");
+
+	if (proxy == nullptr) {
+		/* deprecated proxy configuration */
+		proxy = config_get_string(CONF_HTTP_PROXY_HOST, nullptr);
+		proxy_port = config_get_positive(CONF_HTTP_PROXY_PORT, 0);
+		proxy_user = config_get_string(CONF_HTTP_PROXY_USER, nullptr);
+		proxy_password = config_get_string(CONF_HTTP_PROXY_PASSWORD,
+						   "");
+	}
+
+	CURLM *multi = curl_multi_init();
+	if (multi == nullptr) {
+		error.Set(curl_domain, 0, "curl_multi_init() failed");
+		return false;
+	}
+
+	curl_multi = new CurlMulti(io_thread_get(), multi);
+	return true;
+}
+
+static void
+input_curl_finish(void)
+{
+	BlockingCall(io_thread_get(), [](){
+			delete curl_multi;
+		});
+
+	curl_slist_free_all(http_200_aliases);
+
+	curl_global_cleanup();
+}
+
+/**
+ * Determine the total sizes of all buffers, including portions that
+ * have already been consumed.
+ *
+ * The caller must lock the mutex.
+ */
+gcc_pure
+static size_t
+curl_total_buffer_size(const struct input_curl *c)
+{
+	size_t total = 0;
+
+	for (const auto &i : c->buffers)
+		total += i.TotalSize();
+
+	return total;
+}
+
+input_curl::~input_curl()
+{
+	delete tag;
+
+	input_curl_easy_free_indirect(this);
+}
+
+static bool
+input_curl_check(InputStream *is, Error &error)
+{
+	struct input_curl *c = (struct input_curl *)is;
+
+	bool success = !c->postponed_error.IsDefined();
+	if (!success) {
+		error = std::move(c->postponed_error);
+		c->postponed_error.Clear();
+	}
+
+	return success;
+}
+
+static Tag *
+input_curl_tag(InputStream *is)
+{
+	struct input_curl *c = (struct input_curl *)is;
+	Tag *tag = c->tag;
+
+	c->tag = nullptr;
+	return tag;
+}
+
+static bool
+fill_buffer(struct input_curl *c, Error &error)
+{
+	while (c->easy != nullptr && c->buffers.empty())
+		c->base.cond.wait(c->base.mutex);
+
+	if (c->postponed_error.IsDefined()) {
+		error = std::move(c->postponed_error);
+		c->postponed_error.Clear();
+		return false;
+	}
+
+	return !c->buffers.empty();
+}
+
+static size_t
+read_from_buffer(IcyMetaDataParser &icy, std::list<CurlInputBuffer> &buffers,
+		 void *dest0, size_t length)
+{
+	auto &buffer = buffers.front();
+	uint8_t *dest = (uint8_t *)dest0;
+	size_t nbytes = 0;
+
+	if (length > buffer.Available())
+		length = buffer.Available();
+
+	while (true) {
+		size_t chunk;
+
+		chunk = icy.Data(length);
+		if (chunk > 0) {
+			const bool empty = !buffer.Read(dest, chunk);
+
+			nbytes += chunk;
+			dest += chunk;
+			length -= chunk;
+
+			if (empty) {
+				buffers.pop_front();
+				break;
+			}
+
+			if (length == 0)
+				break;
+		}
+
+		chunk = icy.Meta(buffer.Begin(), length);
+		if (chunk > 0) {
+			const bool empty = !buffer.Consume(chunk);
+
+			length -= chunk;
+
+			if (empty) {
+				buffers.pop_front();
+				break;
+			}
+
+			if (length == 0)
+				break;
+		}
+	}
+
+	return nbytes;
+}
+
+static void
+copy_icy_tag(struct input_curl *c)
+{
+	Tag *tag = c->icy.ReadTag();
+
+	if (tag == nullptr)
+		return;
+
+	delete c->tag;
+
+	if (!c->meta_name.empty() && !tag->HasType(TAG_NAME)) {
+		TagBuilder tag_builder(std::move(*tag));
+		tag_builder.AddItem(TAG_NAME, c->meta_name.c_str());
+		*tag = tag_builder.Commit();
+	}
+
+	c->tag = tag;
+}
+
+static bool
+input_curl_available(InputStream *is)
+{
+	struct input_curl *c = (struct input_curl *)is;
+
+	return c->postponed_error.IsDefined() || c->easy == nullptr ||
+		!c->buffers.empty();
+}
+
+static size_t
+input_curl_read(InputStream *is, void *ptr, size_t size,
+		Error &error)
+{
+	struct input_curl *c = (struct input_curl *)is;
+	bool success;
+	size_t nbytes = 0;
+	char *dest = (char *)ptr;
+
+	do {
+		/* fill the buffer */
+
+		success = fill_buffer(c, error);
+		if (!success)
+			return 0;
+
+		/* send buffer contents */
+
+		while (size > 0 && !c->buffers.empty()) {
+			size_t copy = read_from_buffer(c->icy, c->buffers,
+						       dest + nbytes, size);
+
+			nbytes += copy;
+			size -= copy;
+		}
+	} while (nbytes == 0);
+
+	if (c->icy.IsDefined())
+		copy_icy_tag(c);
+
+	is->offset += (InputPlugin::offset_type)nbytes;
+
+	if (c->paused && curl_total_buffer_size(c) < CURL_RESUME_AT) {
+		c->base.mutex.unlock();
+
+		BlockingCall(io_thread_get(), [c](){
+				input_curl_resume(c);
+			});
+
+		c->base.mutex.lock();
+	}
+
+	return nbytes;
+}
+
+static void
+input_curl_close(InputStream *is)
+{
+	struct input_curl *c = (struct input_curl *)is;
+
+	delete c;
+}
+
+static bool
+input_curl_eof(gcc_unused InputStream *is)
+{
+	struct input_curl *c = (struct input_curl *)is;
+
+	return c->easy == nullptr && c->buffers.empty();
+}
+
+/** called by curl when new data is available */
+static size_t
+input_curl_headerfunction(void *ptr, size_t size, size_t nmemb, void *stream)
+{
+	struct input_curl *c = (struct input_curl *)stream;
+	char name[64];
+
+	size *= nmemb;
+
+	const char *header = (const char *)ptr;
+	const char *end = header + size;
+
+	const char *value = (const char *)memchr(header, ':', size);
+	if (value == nullptr || (size_t)(value - header) >= sizeof(name))
+		return size;
+
+	memcpy(name, header, value - header);
+	name[value - header] = 0;
+
+	/* skip the colon */
+
+	++value;
+
+	/* strip the value */
+
+	while (value < end && IsWhitespaceOrNull(*value))
+		++value;
+
+	while (end > value && IsWhitespaceOrNull(end[-1]))
+		--end;
+
+	if (StringEqualsCaseASCII(name, "accept-ranges")) {
+		/* a stream with icy-metadata is not seekable */
+		if (!c->icy.IsDefined())
+			c->base.seekable = true;
+	} else if (StringEqualsCaseASCII(name, "content-length")) {
+		char buffer[64];
+
+		if ((size_t)(end - header) >= sizeof(buffer))
+			return size;
+
+		memcpy(buffer, value, end - value);
+		buffer[end - value] = 0;
+
+		c->base.size = c->base.offset + ParseUint64(buffer);
+	} else if (StringEqualsCaseASCII(name, "content-type")) {
+		c->base.mime.assign(value, end);
+	} else if (StringEqualsCaseASCII(name, "icy-name") ||
+		   StringEqualsCaseASCII(name, "ice-name") ||
+		   StringEqualsCaseASCII(name, "x-audiocast-name")) {
+		c->meta_name.assign(value, end);
+
+		delete c->tag;
+
+		TagBuilder tag_builder;
+		tag_builder.AddItem(TAG_NAME, c->meta_name.c_str());
+
+		c->tag = tag_builder.CommitNew();
+	} else if (StringEqualsCaseASCII(name, "icy-metaint")) {
+		char buffer[64];
+		size_t icy_metaint;
+
+		if ((size_t)(end - header) >= sizeof(buffer) ||
+		    c->icy.IsDefined())
+			return size;
+
+		memcpy(buffer, value, end - value);
+		buffer[end - value] = 0;
+
+		icy_metaint = ParseUint64(buffer);
+		FormatDebug(curl_domain, "icy-metaint=%zu", icy_metaint);
+
+		if (icy_metaint > 0) {
+			c->icy.Start(icy_metaint);
+
+			/* a stream with icy-metadata is not
+			   seekable */
+			c->base.seekable = false;
+		}
+	}
+
+	return size;
+}
+
+/** called by curl when new data is available */
+static size_t
+input_curl_writefunction(void *ptr, size_t size, size_t nmemb, void *stream)
+{
+	struct input_curl *c = (struct input_curl *)stream;
+
+	size *= nmemb;
+	if (size == 0)
+		return 0;
+
+	const ScopeLock protect(c->base.mutex);
+
+	if (curl_total_buffer_size(c) + size >= CURL_MAX_BUFFERED) {
+		c->paused = true;
+		return CURL_WRITEFUNC_PAUSE;
+	}
+
+	c->buffers.emplace_back(ptr, size);
+	c->base.ready = true;
+
+	c->base.cond.broadcast();
+	return size;
+}
+
+static bool
+input_curl_easy_init(struct input_curl *c, Error &error)
+{
+	CURLcode code;
+
+	c->easy = curl_easy_init();
+	if (c->easy == nullptr) {
+		error.Set(curl_domain, "curl_easy_init() failed");
+		return false;
+	}
+
+	curl_easy_setopt(c->easy, CURLOPT_PRIVATE, (void *)c);
+	curl_easy_setopt(c->easy, CURLOPT_USERAGENT,
+			 "Music Player Daemon " VERSION);
+	curl_easy_setopt(c->easy, CURLOPT_HEADERFUNCTION,
+			 input_curl_headerfunction);
+	curl_easy_setopt(c->easy, CURLOPT_WRITEHEADER, c);
+	curl_easy_setopt(c->easy, CURLOPT_WRITEFUNCTION,
+			 input_curl_writefunction);
+	curl_easy_setopt(c->easy, CURLOPT_WRITEDATA, c);
+	curl_easy_setopt(c->easy, CURLOPT_HTTP200ALIASES, http_200_aliases);
+	curl_easy_setopt(c->easy, CURLOPT_FOLLOWLOCATION, 1);
+	curl_easy_setopt(c->easy, CURLOPT_NETRC, 1);
+	curl_easy_setopt(c->easy, CURLOPT_MAXREDIRS, 5);
+	curl_easy_setopt(c->easy, CURLOPT_FAILONERROR, true);
+	curl_easy_setopt(c->easy, CURLOPT_ERRORBUFFER, c->error);
+	curl_easy_setopt(c->easy, CURLOPT_NOPROGRESS, 1l);
+	curl_easy_setopt(c->easy, CURLOPT_NOSIGNAL, 1l);
+	curl_easy_setopt(c->easy, CURLOPT_CONNECTTIMEOUT, 10l);
+
+	if (proxy != nullptr)
+		curl_easy_setopt(c->easy, CURLOPT_PROXY, proxy);
+
+	if (proxy_port > 0)
+		curl_easy_setopt(c->easy, CURLOPT_PROXYPORT, (long)proxy_port);
+
+	if (proxy_user != nullptr && proxy_password != nullptr) {
+		char proxy_auth_str[1024];
+		snprintf(proxy_auth_str, sizeof(proxy_auth_str),
+			 "%s:%s",
+			 proxy_user, proxy_password);
+		curl_easy_setopt(c->easy, CURLOPT_PROXYUSERPWD, proxy_auth_str);
+	}
+
+	code = curl_easy_setopt(c->easy, CURLOPT_URL, c->base.uri.c_str());
+	if (code != CURLE_OK) {
+		error.Format(curl_domain, code,
+			     "curl_easy_setopt() failed: %s",
+			     curl_easy_strerror(code));
+		return false;
+	}
+
+	c->request_headers = nullptr;
+	c->request_headers = curl_slist_append(c->request_headers,
+					       "Icy-Metadata: 1");
+	curl_easy_setopt(c->easy, CURLOPT_HTTPHEADER, c->request_headers);
+
+	return true;
+}
+
+static bool
+input_curl_seek(InputStream *is, InputPlugin::offset_type offset,
+		int whence,
+		Error &error)
+{
+	struct input_curl *c = (struct input_curl *)is;
+	bool ret;
+
+	assert(is->ready);
+
+	if (whence == SEEK_SET && offset == is->offset)
+		/* no-op */
+		return true;
+
+	if (!is->seekable)
+		return false;
+
+	/* calculate the absolute offset */
+
+	switch (whence) {
+	case SEEK_SET:
+		break;
+
+	case SEEK_CUR:
+		offset += is->offset;
+		break;
+
+	case SEEK_END:
+		if (is->size < 0)
+			/* stream size is not known */
+			return false;
+
+		offset += is->size;
+		break;
+
+	default:
+		return false;
+	}
+
+	if (offset < 0)
+		return false;
+
+	/* check if we can fast-forward the buffer */
+
+	while (offset > is->offset && !c->buffers.empty()) {
+		auto &buffer = c->buffers.front();
+		size_t length = buffer.Available();
+		if (offset - is->offset < (InputPlugin::offset_type)length)
+			length = offset - is->offset;
+
+		const bool empty = !buffer.Consume(length);
+		if (empty)
+			c->buffers.pop_front();
+
+		is->offset += length;
+	}
+
+	if (offset == is->offset)
+		return true;
+
+	/* close the old connection and open a new one */
+
+	c->base.mutex.unlock();
+
+	input_curl_easy_free_indirect(c);
+	c->buffers.clear();
+
+	is->offset = offset;
+	if (is->offset == is->size) {
+		/* seek to EOF: simulate empty result; avoid
+		   triggering a "416 Requested Range Not Satisfiable"
+		   response */
+		return true;
+	}
+
+	ret = input_curl_easy_init(c, error);
+	if (!ret)
+		return false;
+
+	/* send the "Range" header */
+
+	if (is->offset > 0) {
+		sprintf(c->range, "%lld-", (long long)is->offset);
+		curl_easy_setopt(c->easy, CURLOPT_RANGE, c->range);
+	}
+
+	c->base.ready = false;
+
+	if (!input_curl_easy_add_indirect(c, error))
+		return false;
+
+	c->base.mutex.lock();
+
+	while (!c->base.ready)
+		c->base.cond.wait(c->base.mutex);
+
+	if (c->postponed_error.IsDefined()) {
+		error = std::move(c->postponed_error);
+		c->postponed_error.Clear();
+		return false;
+	}
+
+	return true;
+}
+
+static InputStream *
+input_curl_open(const char *url, Mutex &mutex, Cond &cond,
+		Error &error)
+{
+	if (memcmp(url, "http://",  7) != 0 &&
+	    memcmp(url, "https://", 8) != 0)
+		return nullptr;
+
+	struct input_curl *c = new input_curl(url, mutex, cond);
+
+	if (!input_curl_easy_init(c, error)) {
+		delete c;
+		return nullptr;
+	}
+
+	if (!input_curl_easy_add_indirect(c, error)) {
+		delete c;
+		return nullptr;
+	}
+
+	return &c->base;
+}
+
+const struct InputPlugin input_plugin_curl = {
+	"curl",
+	input_curl_init,
+	input_curl_finish,
+	input_curl_open,
+	input_curl_close,
+	input_curl_check,
+	nullptr,
+	input_curl_tag,
+	input_curl_available,
+	input_curl_read,
+	input_curl_eof,
+	input_curl_seek,
+};