Make the list of lyrics fetchers customizable

NEWS

@@ -6,6 +6,7 @@ ncmpcpp-0.8 (????-??-??)
 * Lyrics from files containing DOS line endings now load properly on Linux.
 * Added support for fetching lyrics from genius.com.
 * Added support for fetching lyrics from tekstowo.pl.
+* The list of lyrics fetchers can now be set via configuration file.
 
 ncmpcpp-0.7.7 (2016-10-31)
 * Fixed compilation on 32bit platforms.

doc/config

@@ -368,6 +368,8 @@
 #
 #lines_scrolled = 2
 #
+#lyrics_fetchers = lyricwiki, azlyrics, genius, sing365, lyricsmania, metrolyrics, justsomelyrics, tekstowo, internet
+#
 #follow_now_playing_lyrics = no
 #
 #fetch_lyrics_for_current_song_in_background = no

doc/ncmpcpp.1

@@ -244,6 +244,9 @@ If enabled, cyclic scrolling is used (e.g. if you press down arrow being at the
 .B lines_scrolled = NUMBER
 Number of lines that are scrolled with mouse wheel.
 .TP
+.B lyrics_fetchers = FETCHERS
+Comma separated list of lyrics fetchers.
+.TP
 .B follow_now_playing_lyrics = yes/no
 If enabled, lyrics will be switched at song's change to currently playing one's (Note: this works only if you are viewing lyrics of item from Playlist).
 .TP

src/lyrics.cpp

@@ -43,7 +43,7 @@ using Global::MainHeight;
 using Global::MainStartY;
 
 #ifdef HAVE_CURL_CURL_H
-LyricsFetcher **Lyrics::itsFetcher = 0;
+LyricsFetcher *Lyrics::itsFetcher = nullptr;
 std::queue<MPD::Song *> Lyrics::itsToDownload;
 pthread_mutex_t Lyrics::itsDIBLock = PTHREAD_MUTEX_INITIALIZER;
 size_t Lyrics::itsWorkersNumber = 0;
@@ -207,16 +207,20 @@ void Lyrics::DownloadInBackgroundImplHelper(const MPD::Song &s)
 	std::string title = Curl::escape(s.getTitle());
 	
 	LyricsFetcher::Result result;
-	bool fetcher_defined = itsFetcher && *itsFetcher;
-	for (LyricsFetcher **plugin = fetcher_defined ? itsFetcher : lyricsPlugins; *plugin != 0; ++plugin)
+
+	if (itsFetcher == nullptr)
 	{
-		result = (*plugin)->fetch(artist, title);
-		if (result.first)
-			break;
-		if (fetcher_defined)
-			break;
+		for (auto &fetcher : Config.lyrics_fetchers)
+		{
+			result = fetcher->fetch(artist, title);
+			if (result.first)
+				break;
+		}
 	}
-	if (result.first == true)
+	else
+		itsFetcher->fetch(artist, title);
+
+	if (result.first)
 		Save(GenerateFilename(s), result.second);
 }
 
@@ -224,25 +228,38 @@ void *Lyrics::Download()
 {
 	std::string artist = Curl::escape(itsSong.getArtist());
 	std::string title_ = Curl::escape(itsSong.getTitle());
-	
-	LyricsFetcher::Result result;
-	
-	// if one of plugins is selected, try only this one,
-	// otherwise try all of them until one of them succeeds
-	bool fetcher_defined = itsFetcher && *itsFetcher;
-	for (LyricsFetcher **plugin = fetcher_defined ? itsFetcher : lyricsPlugins; *plugin != 0; ++plugin)
-	{
-		w << "Fetching lyrics from " << NC::Format::Bold << (*plugin)->name() << NC::Format::NoBold << "... ";
-		result = (*plugin)->fetch(artist, title_);
+
+	auto fetch_lyrics = [&](auto &fetcher) {
+		w << "Fetching lyrics from "
+		  << NC::Format::Bold
+		  << fetcher->name()
+		  << NC::Format::NoBold << "... ";
+		auto result = fetcher->fetch(artist, title_);
 		if (result.first == false)
-			w << NC::Color::Red << result.second << NC::Color::End << '\n';
-		else
-			break;
-		if (fetcher_defined)
-			break;
+		{
+			w << NC::Color::Red
+			  << result.second
+			  << NC::Color::End
+			  << '\n';
+		}
+		return result;
+	};
+
+	LyricsFetcher::Result result;
+
+	if (itsFetcher == nullptr)
+	{
+		for (auto &fetcher : Config.lyrics_fetchers)
+		{
+			result = fetch_lyrics(fetcher);
+			if (result.first)
+				break;
+		}
 	}
-	
-	if (result.first == true)
+	else
+		result = fetch_lyrics(itsFetcher);
+
+	if (result.first)
 	{
 		Save(itsFilename, result.second);
 		w.clear();
@@ -401,14 +418,28 @@ void Lyrics::Refetch()
 
 void Lyrics::ToggleFetcher()
 {
-	if (itsFetcher && *itsFetcher)
-		++itsFetcher;
+	if (itsFetcher != nullptr)
+	{
+		auto fetcher = std::find_if(Config.lyrics_fetchers.begin(),
+		                            Config.lyrics_fetchers.end(),
+		                            [](auto &f) { return f.get() == itsFetcher; });
+		assert(fetcher != Config.lyrics_fetchers.end());
+		++fetcher;
+		if (fetcher != Config.lyrics_fetchers.end())
+			itsFetcher = fetcher->get();
+		else
+			itsFetcher = nullptr;
+	}
 	else
-		itsFetcher = &lyricsPlugins[0];
-	if (*itsFetcher)
-		Statusbar::printf("Using lyrics database: %s", (*itsFetcher)->name());
+	{
+		assert(!Config.lyrics_fetchers.empty());
+		itsFetcher = Config.lyrics_fetchers[0].get();
+	}
+
+	if (itsFetcher != nullptr)
+		Statusbar::printf("Using lyrics fetcher: %s", itsFetcher->name());
 	else
-		Statusbar::print("Using all lyrics databases");
+		Statusbar::print("Using all lyrics fetchers");
 }
 
 void Lyrics::Take()

src/lyrics.h

@@ -83,7 +83,7 @@ private:
 	bool isDownloadInProgress;
 	pthread_t itsDownloader;
 	
-	static LyricsFetcher **itsFetcher;
+	static LyricsFetcher *itsFetcher;
 #	endif // HAVE_CURL_CURL_H
 	
 	size_t itsScrollBegin;

src/lyrics_fetcher.cpp

@@ -36,19 +36,28 @@
 #include "utility/html.h"
 #include "utility/string.h"
 
-LyricsFetcher *lyricsPlugins[] =
+std::unique_ptr<LyricsFetcher> toLyricsFetcher(const std::string &s)
 {
-	new LyricwikiFetcher(),
-	new GeniusLyricsFetcher(),
-	new AzLyricsFetcher(),
-	new Sing365Fetcher(),
-	new LyricsmaniaFetcher(),
-	new MetrolyricsFetcher(),
-	new JustSomeLyricsFetcher(),
-	new TekstowoLyricsFetcher(),
-	new InternetLyricsFetcher(),
-	0
-};
+	if (s == "lyricwiki")
+		return std::make_unique<LyricwikiFetcher>();
+	else if (s == "azlyrics")
+		return std::make_unique<AzLyricsFetcher>();
+	else if (s == "genius")
+		return std::make_unique<GeniusFetcher>();
+	else if (s == "sing365")
+		return std::make_unique<Sing365Fetcher>();
+	else if (s == "lyricsmania")
+		return std::make_unique<LyricsmaniaFetcher>();
+	else if (s == "metrolyrics")
+		return std::make_unique<MetrolyricsFetcher>();
+	else if (s == "justsomelyrics")
+		return std::make_unique<JustSomeLyricsFetcher>();
+	else if (s == "tekstowo")
+		return std::make_unique<TekstowoFetcher>();
+	else if (s == "internet")
+		return std::make_unique<InternetLyricsFetcher>();
+	throw std::runtime_error("no lyrics fetcher named '" + s + "'");
+}
 
 const char LyricsFetcher::msgNotFound[] = "Not found";
 

src/lyrics_fetcher.h

@@ -25,6 +25,7 @@
 
 #ifdef HAVE_CURL_CURL_H
 
+#include <memory>
 #include <string>
 
 struct LyricsFetcher
@@ -46,6 +47,12 @@ protected:
 	static const char msgNotFound[];
 };
 
+typedef std::vector<std::unique_ptr<LyricsFetcher>> LyricsFetchers;
+
+std::unique_ptr<LyricsFetcher> toLyricsFetcher(const std::string &s);
+
+/**********************************************************************/
+
 struct LyricwikiFetcher : public LyricsFetcher
 {
 	virtual const char *name() const override { return "lyricwiki.com"; }
@@ -116,7 +123,7 @@ protected:
 	virtual const char *regex() const override { return "<div class=\"lyricsh\">.*?</h2>.*<div>(.*?)</div>"; }
 };
 
-struct GeniusLyricsFetcher : public GoogleLyricsFetcher
+struct GeniusFetcher : public GoogleLyricsFetcher
 {
 	virtual const char *name() const override { return "genius.com"; }
 
@@ -124,7 +131,7 @@ protected:
 	virtual const char *regex() const override { return "<lyrics.*?>(.*?)</lyrics>"; }
 };
 
-struct TekstowoLyricsFetcher : public GoogleLyricsFetcher
+struct TekstowoFetcher : public GoogleLyricsFetcher
 {
 	virtual const char *name() const override { return "tekstowo.pl"; }
 
@@ -147,8 +154,6 @@ private:
 	std::string URL;
 };
 
-extern LyricsFetcher *lyricsPlugins[];
-
 #endif // HAVE_CURL_CURL_H
 
 #endif // NCMPCPP_LYRICS_FETCHER_H

src/settings.cpp

@@ -503,6 +503,23 @@ bool Configuration::read(const std::vector<std::string> &config_paths, bool igno
 	p.add("lines_scrolled", assign_default(
 		lines_scrolled, 2
 	));
+		p.add("lyrics_fetchers", option_parser::worker([this](std::string v) {
+		boost::sregex_token_iterator fetcher(v.begin(), v.end(), boost::regex("\\w+")), end;
+		for (; fetcher != end; ++fetcher)
+			lyrics_fetchers.push_back(toLyricsFetcher(*fetcher));
+		if (lyrics_fetchers.empty())
+			throw std::runtime_error("empty list");
+	}, [this] {
+		lyrics_fetchers.push_back(std::make_unique<LyricwikiFetcher>());
+		lyrics_fetchers.push_back(std::make_unique<AzLyricsFetcher>());
+		lyrics_fetchers.push_back(std::make_unique<GeniusFetcher>());
+		lyrics_fetchers.push_back(std::make_unique<Sing365Fetcher>());
+		lyrics_fetchers.push_back(std::make_unique<LyricsmaniaFetcher>());
+		lyrics_fetchers.push_back(std::make_unique<MetrolyricsFetcher>());
+		lyrics_fetchers.push_back(std::make_unique<JustSomeLyricsFetcher>());
+		lyrics_fetchers.push_back(std::make_unique<TekstowoFetcher>());
+		lyrics_fetchers.push_back(std::make_unique<InternetLyricsFetcher>());
+	}));
 	p.add("follow_now_playing_lyrics", yes_no(
 		now_playing_lyrics, false
 	));

src/settings.h

@@ -30,6 +30,7 @@
 
 #include "enums.h"
 #include "format.h"
+#include "lyrics_fetcher.h"
 #include "screen_type.h"
 #include "strbuffer.h"
 
@@ -195,6 +196,8 @@ struct Configuration
 	std::list<ScreenType> screen_sequence;
 
 	SortMode browser_sort_mode;
+
+	LyricsFetchers lyrics_fetchers;
 };
 
 extern Configuration Config;