input/tidal: implement InputPlugin::scan_tags()

Makefile.am

@@ -1378,6 +1378,7 @@ libinput_a_SOURCES += \
 	src/input/plugins/TidalLoginRequest.cxx src/input/plugins/TidalLoginRequest.hxx \
 	src/input/plugins/TidalSessionManager.cxx src/input/plugins/TidalSessionManager.hxx \
 	src/input/plugins/TidalTrackRequest.cxx src/input/plugins/TidalTrackRequest.hxx \
+	src/input/plugins/TidalTagScanner.cxx src/input/plugins/TidalTagScanner.hxx \
 	src/input/plugins/TidalInputPlugin.cxx src/input/plugins/TidalInputPlugin.hxx
 INPUT_LIBS += $(YAJL_LIBS)
 endif

src/input/plugins/TidalInputPlugin.cxx

@@ -21,6 +21,7 @@
 #include "TidalInputPlugin.hxx"
 #include "TidalSessionManager.hxx"
 #include "TidalTrackRequest.hxx"
+#include "TidalTagScanner.hxx"
 #include "TidalError.hxx"
 #include "CurlInputPlugin.hxx"
 #include "PluginUnavailable.hxx"
@@ -223,9 +224,25 @@ OpenTidalInput(const char *uri, Mutex &mutex, Cond &cond)
 	return std::make_unique<TidalInputStream>(uri, track_id, mutex, cond);
 }
 
+static std::unique_ptr<RemoteTagScanner>
+ScanTidalTags(const char *uri, RemoteTagHandler &handler)
+{
+	assert(tidal_session != nullptr);
+
+	const char *track_id = ExtractTidalTrackId(uri);
+	if (track_id == nullptr)
+		return nullptr;
+
+	return std::make_unique<TidalTagScanner>(tidal_session->GetCurl(),
+						 tidal_session->GetBaseUrl(),
+						 tidal_session->GetToken(),
+						 track_id, handler);
+}
+
 const InputPlugin tidal_input_plugin = {
 	"tidal",
 	InitTidalInput,
 	FinishTidalInput,
 	OpenTidalInput,
+	ScanTidalTags,
 };

src/input/plugins/TidalTagScanner.cxx

@@ -0,0 +1,243 @@
+/*
+ * Copyright 2003-2018 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 "TidalTagScanner.hxx"
+#include "TidalErrorParser.hxx"
+#include "lib/yajl/Callbacks.hxx"
+#include "tag/Builder.hxx"
+#include "tag/Tag.hxx"
+
+using Wrapper = Yajl::CallbacksWrapper<TidalTagScanner::ResponseParser>;
+static constexpr yajl_callbacks parse_callbacks = {
+	nullptr,
+	nullptr,
+	Wrapper::Integer,
+	nullptr,
+	nullptr,
+	Wrapper::String,
+	Wrapper::StartMap,
+	Wrapper::MapKey,
+	Wrapper::EndMap,
+	nullptr,
+	nullptr,
+};
+
+class TidalTagScanner::ResponseParser final : public YajlResponseParser {
+	enum class State {
+		NONE,
+		TITLE,
+		DURATION,
+		ARTIST,
+		ARTIST_NAME,
+		ALBUM,
+		ALBUM_TITLE,
+	} state = State::NONE;
+
+	unsigned map_depth = 0;
+
+	TagBuilder tag;
+
+public:
+	explicit ResponseParser() noexcept
+		:YajlResponseParser(&parse_callbacks, nullptr, this) {}
+
+	Tag GetTag() {
+		return tag.Commit();
+	}
+
+	/* yajl callbacks */
+	bool Integer(long long value) noexcept;
+	bool String(StringView value) noexcept;
+	bool StartMap() noexcept;
+	bool MapKey(StringView value) noexcept;
+	bool EndMap() noexcept;
+};
+
+static std::string
+MakeTrackUrl(const char *base_url, const char *track_id)
+{
+	return std::string(base_url)
+		+ "/tracks/"
+		+ track_id
+		// TODO: configurable countryCode?
+		+ "?countryCode=US";
+}
+
+TidalTagScanner::TidalTagScanner(CurlGlobal &curl,
+				 const char *base_url, const char *token,
+				 const char *track_id,
+				 RemoteTagHandler &_handler)
+	:request(curl, MakeTrackUrl(base_url, track_id).c_str(), *this),
+	 handler(_handler)
+{
+	request_headers.Append((std::string("X-Tidal-Token:")
+				+ token).c_str());
+	request.SetOption(CURLOPT_HTTPHEADER, request_headers.Get());
+}
+
+TidalTagScanner::~TidalTagScanner() noexcept
+{
+	request.StopIndirect();
+}
+
+std::unique_ptr<CurlResponseParser>
+TidalTagScanner::MakeParser(unsigned status,
+			      std::multimap<std::string, std::string> &&headers)
+{
+	if (status != 200)
+		return std::make_unique<TidalErrorParser>(status, headers);
+
+	auto i = headers.find("content-type");
+	if (i == headers.end() || i->second.find("/json") == i->second.npos)
+		throw std::runtime_error("Not a JSON response from Tidal");
+
+	return std::make_unique<ResponseParser>();
+}
+
+void
+TidalTagScanner::FinishParser(std::unique_ptr<CurlResponseParser> p)
+{
+	assert(dynamic_cast<ResponseParser *>(p.get()) != nullptr);
+	auto &rp = (ResponseParser &)*p;
+	handler.OnRemoteTag(rp.GetTag());
+}
+
+void
+TidalTagScanner::OnError(std::exception_ptr e) noexcept
+{
+	handler.OnRemoteTagError(e);
+}
+
+inline bool
+TidalTagScanner::ResponseParser::Integer(long long value) noexcept
+{
+	switch (state) {
+	case State::NONE:
+	case State::TITLE:
+	case State::ARTIST:
+	case State::ARTIST_NAME:
+	case State::ALBUM:
+	case State::ALBUM_TITLE:
+		break;
+
+	case State::DURATION:
+		if (map_depth == 1 && value > 0)
+			tag.SetDuration(SignedSongTime::FromS((unsigned)value));
+		break;
+	}
+
+	return true;
+}
+
+inline bool
+TidalTagScanner::ResponseParser::String(StringView value) noexcept
+{
+	switch (state) {
+	case State::NONE:
+	case State::DURATION:
+	case State::ARTIST:
+	case State::ALBUM:
+		break;
+
+	case State::TITLE:
+		if (map_depth == 1)
+			tag.AddItem(TAG_TITLE, value);
+		break;
+
+	case State::ARTIST_NAME:
+		if (map_depth == 2)
+			tag.AddItem(TAG_ARTIST, value);
+		break;
+
+	case State::ALBUM_TITLE:
+		if (map_depth == 2)
+			tag.AddItem(TAG_ALBUM, value);
+		break;
+	}
+
+	return true;
+}
+
+inline bool
+TidalTagScanner::ResponseParser::StartMap() noexcept
+{
+	++map_depth;
+	return true;
+}
+
+inline bool
+TidalTagScanner::ResponseParser::MapKey(StringView value) noexcept
+{
+	switch (map_depth) {
+	case 1:
+		if (value.Equals("title"))
+			state = State::TITLE;
+		else if (value.Equals("duration"))
+			state = State::DURATION;
+		else if (value.Equals("artist"))
+			state = State::ARTIST;
+		else if (value.Equals("album"))
+			state = State::ALBUM;
+		else
+			state = State::NONE;
+		break;
+
+	case 2:
+		switch (state) {
+		case State::NONE:
+		case State::TITLE:
+		case State::DURATION:
+			break;
+
+		case State::ARTIST:
+		case State::ARTIST_NAME:
+			if (value.Equals("name"))
+				state = State::ARTIST_NAME;
+			else
+				state = State::ARTIST;
+			break;
+
+		case State::ALBUM:
+		case State::ALBUM_TITLE:
+			if (value.Equals("title"))
+				state = State::ALBUM_TITLE;
+			else
+				state = State::ALBUM;
+			break;
+		}
+		break;
+	}
+
+	return true;
+}
+
+inline bool
+TidalTagScanner::ResponseParser::EndMap() noexcept
+{
+	switch (map_depth) {
+	case 2:
+		state = State::NONE;
+		break;
+	}
+
+	--map_depth;
+
+	return true;
+}

src/input/plugins/TidalTagScanner.hxx

@@ -0,0 +1,62 @@
+/*
+ * Copyright 2003-2018 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 TIDAL_TAG_SCANNER_HXX
+#define TIDAL_TAG_SCANNER_HXX
+
+#include "check.h"
+#include "lib/curl/Delegate.hxx"
+#include "lib/curl/Slist.hxx"
+#include "lib/curl/Request.hxx"
+#include "input/RemoteTagScanner.hxx"
+
+class TidalTagScanner final
+	: public RemoteTagScanner, DelegateCurlResponseHandler
+{
+	CurlSlist request_headers;
+
+	CurlRequest request;
+
+	RemoteTagHandler &handler;
+
+public:
+	class ResponseParser;
+
+	TidalTagScanner(CurlGlobal &curl,
+			const char *base_url, const char *token,
+			const char *track_id,
+			RemoteTagHandler &_handler);
+
+	~TidalTagScanner() noexcept override;
+
+	void Start() override {
+		request.StartIndirect();
+	}
+
+private:
+	/* virtual methods from DelegateCurlResponseHandler */
+	std::unique_ptr<CurlResponseParser> MakeParser(unsigned status,
+						       std::multimap<std::string, std::string> &&headers) override;
+	void FinishParser(std::unique_ptr<CurlResponseParser> p) override;
+
+	/* virtual methods from CurlResponseHandler */
+	void OnError(std::exception_ptr e) noexcept override;
+};
+
+#endif