Move lyrics providers to own thread

src/core/application.cpp

@@ -171,16 +171,16 @@ class ApplicationImpl {
         lyrics_providers_([app]() {
           LyricsProviders *lyrics_providers = new LyricsProviders(app);
           // Initialize the repository of lyrics providers.
-          lyrics_providers->AddProvider(new GeniusLyricsProvider(app->network()));
+          lyrics_providers->AddProvider(new GeniusLyricsProvider(lyrics_providers->network()));
-          lyrics_providers->AddProvider(new OVHLyricsProvider(app->network()));
+          lyrics_providers->AddProvider(new OVHLyricsProvider(lyrics_providers->network()));
-          lyrics_providers->AddProvider(new LoloLyricsProvider(app->network()));
+          lyrics_providers->AddProvider(new LoloLyricsProvider(lyrics_providers->network()));
-          lyrics_providers->AddProvider(new MusixmatchLyricsProvider(app->network()));
+          lyrics_providers->AddProvider(new MusixmatchLyricsProvider(lyrics_providers->network()));
-          lyrics_providers->AddProvider(new ChartLyricsProvider(app->network()));
+          lyrics_providers->AddProvider(new ChartLyricsProvider(lyrics_providers->network()));
-          lyrics_providers->AddProvider(new SongLyricsComLyricsProvider(app->network()));
+          lyrics_providers->AddProvider(new SongLyricsComLyricsProvider(lyrics_providers->network()));
-          lyrics_providers->AddProvider(new AzLyricsComLyricsProvider(app->network()));
+          lyrics_providers->AddProvider(new AzLyricsComLyricsProvider(lyrics_providers->network()));
-          lyrics_providers->AddProvider(new ElyricsNetLyricsProvider(app->network()));
+          lyrics_providers->AddProvider(new ElyricsNetLyricsProvider(lyrics_providers->network()));
-          lyrics_providers->AddProvider(new LetrasLyricsProvider(app->network()));
+          lyrics_providers->AddProvider(new LetrasLyricsProvider(lyrics_providers->network()));
-          lyrics_providers->AddProvider(new LyricFindLyricsProvider(app->network()));
+          lyrics_providers->AddProvider(new LyricFindLyricsProvider(lyrics_providers->network()));
           lyrics_providers->ReloadSettings();
           return lyrics_providers;
         }),

src/lyrics/azlyricscomlyricsprovider.cpp

@@ -17,7 +17,8 @@
  *
  */
 
-#include <QObject>
+#include <QApplication>
+#include <QThread>
 #include <QString>
 #include <QUrl>
 #include <QRegularExpression>
@@ -46,6 +47,8 @@ QUrl AzLyricsComLyricsProvider::Url(const LyricsSearchRequest &request) {
 
 QString AzLyricsComLyricsProvider::StringFixup(const QString &text) {
 
+  Q_ASSERT(QThread::currentThread() != qApp->thread());
+
   static const QRegularExpression regex_words_numbers_and_dash(QStringLiteral("[^\\w0-9\\-]"));
   return Utilities::Transliterate(text).remove(regex_words_numbers_and_dash).toLower();
 

src/lyrics/chartlyricsprovider.cpp

@@ -19,7 +19,8 @@
 
 #include "config.h"
 
-#include <QObject>
+#include <QApplication>
+#include <QThread>
 #include <QByteArray>
 #include <QVariant>
 #include <QString>
@@ -54,7 +55,9 @@ ChartLyricsProvider::~ChartLyricsProvider() {
 
 }
 
-bool ChartLyricsProvider::StartSearch(const int id, const LyricsSearchRequest &request) {
+void ChartLyricsProvider::StartSearch(const int id, const LyricsSearchRequest &request) {
+
+  Q_ASSERT(QThread::currentThread() != qApp->thread());
 
   QUrlQuery url_query;
   url_query.addQueryItem(QStringLiteral("artist"), QString::fromUtf8(QUrl::toPercentEncoding(request.artist)));
@@ -68,12 +71,8 @@ bool ChartLyricsProvider::StartSearch(const int id, const LyricsSearchRequest &r
   replies_ << reply;
   QObject::connect(reply, &QNetworkReply::finished, this, [this, reply, id, request]() { HandleSearchReply(reply, id, request); });
 
-  return true;
-
 }
 
-void ChartLyricsProvider::CancelSearch(const int) {}
-
 void ChartLyricsProvider::HandleSearchReply(QNetworkReply *reply, const int id, const LyricsSearchRequest &request) {
 
   if (!replies_.contains(reply)) return;

src/lyrics/chartlyricsprovider.h

@@ -41,12 +41,12 @@ class ChartLyricsProvider : public LyricsProvider {
   explicit ChartLyricsProvider(SharedPtr<NetworkAccessManager> network, QObject *parent = nullptr);
   ~ChartLyricsProvider() override;
 
-  bool StartSearch(const int id, const LyricsSearchRequest &request) override;
-  void CancelSearch(int id) override;
-
  private:
   void Error(const QString &error, const QVariant &debug = QVariant()) override;
 
+ protected Q_SLOTS:
+  void StartSearch(const int id, const LyricsSearchRequest &request) override;
+
  private Q_SLOTS:
   void HandleSearchReply(QNetworkReply *reply, const int id, const LyricsSearchRequest &request);
 

src/lyrics/elyricsnetlyricsprovider.cpp

@@ -17,7 +17,8 @@
  *
  */
 
-#include <QObject>
+#include <QApplication>
+#include <QThread>
 #include <QString>
 #include <QUrl>
 #include <QRegularExpression>
@@ -46,6 +47,8 @@ QUrl ElyricsNetLyricsProvider::Url(const LyricsSearchRequest &request) {
 
 QString ElyricsNetLyricsProvider::StringFixup(const QString &text) {
 
+  Q_ASSERT(QThread::currentThread() != qApp->thread());
+
   static const QRegularExpression regex_illegal_characters(QStringLiteral("[^\\w0-9_,&\\-\\(\\) ]"));
   static const QRegularExpression regex_duplicate_whitespaces(QStringLiteral(" {2,}"));
 

src/lyrics/geniuslyricsprovider.cpp

@@ -22,7 +22,8 @@
 #include <utility>
 #include <memory>
 
-#include <QObject>
+#include <QApplication>
+#include <QThread>
 #include <QList>
 #include <QByteArray>
 #include <QVariant>
@@ -42,6 +43,7 @@
 #include <QJsonValue>
 #include <QJsonParseError>
 #include <QMessageBox>
+#include <QMutexLocker>
 
 #include "core/logging.h"
 #include "core/shared_ptr.h"
@@ -70,7 +72,7 @@ GeniusLyricsProvider::GeniusLyricsProvider(SharedPtr<NetworkAccessManager> netwo
   Settings s;
   s.beginGroup(kSettingsGroup);
   if (s.contains("access_token")) {
-    access_token_ = s.value("access_token").toString();
+    set_access_token(s.value("access_token").toString());
   }
   s.endGroup();
 
@@ -87,6 +89,27 @@ GeniusLyricsProvider::~GeniusLyricsProvider() {
 
 }
 
+QString GeniusLyricsProvider::access_token() const {
+
+  QMutexLocker l(&mutex_access_token_);
+  return access_token_;
+
+}
+
+void GeniusLyricsProvider::clear_access_token() {
+
+  QMutexLocker l(&mutex_access_token_);
+  access_token_.clear();
+
+}
+
+void GeniusLyricsProvider::set_access_token(const QString &access_token) {
+
+  QMutexLocker l(&mutex_access_token_);
+  access_token_ = access_token;
+
+}
+
 void GeniusLyricsProvider::Authenticate() {
 
   QUrl redirect_url(QString::fromLatin1(kOAuthRedirectUrl));
@@ -277,11 +300,13 @@ void GeniusLyricsProvider::AccessTokenRequestFinished(QNetworkReply *reply) {
     return;
   }
 
-  access_token_ = json_obj[QLatin1String("access_token")].toString();
+  const QString access_token = json_obj[QLatin1String("access_token")].toString();
+
+  set_access_token(access_token);
 
   Settings s;
   s.beginGroup(kSettingsGroup);
-  s.setValue("access_token", access_token_);
+  s.setValue("access_token", access_token);
   s.endGroup();
 
   qLog(Debug) << "Genius: Authentication was successful.";
@@ -291,15 +316,20 @@ void GeniusLyricsProvider::AccessTokenRequestFinished(QNetworkReply *reply) {
 
 }
 
-bool GeniusLyricsProvider::StartSearch(const int id, const LyricsSearchRequest &request) {
+void GeniusLyricsProvider::StartSearch(const int id, const LyricsSearchRequest &request) {
 
-  if (access_token_.isEmpty()) return false;
+  Q_ASSERT(QThread::currentThread() != qApp->thread());
 
   GeniusLyricsSearchContextPtr search = make_shared<GeniusLyricsSearchContext>();
   search->id = id;
   search->request = request;
   requests_search_.insert(id, search);
 
+  if (access_token().isEmpty()) {
+    EndSearch(search);
+    return;
+  }
+
   QUrlQuery url_query;
   url_query.addQueryItem(QStringLiteral("q"), QString::fromLatin1(QUrl::toPercentEncoding(QStringLiteral("%1 %2").arg(request.artist, request.title))));
 
@@ -307,19 +337,17 @@ bool GeniusLyricsProvider::StartSearch(const int id, const LyricsSearchRequest &
   url.setQuery(url_query);
   QNetworkRequest req(url);
   req.setAttribute(QNetworkRequest::RedirectPolicyAttribute, QNetworkRequest::NoLessSafeRedirectPolicy);
-  req.setRawHeader("Authorization", "Bearer " + access_token_.toUtf8());
+  req.setRawHeader("Authorization", "Bearer " + access_token().toUtf8());
   QNetworkReply *reply = network_->get(req);
   replies_ << reply;
   QObject::connect(reply, &QNetworkReply::finished, this, [this, reply, id]() { HandleSearchReply(reply, id); });
 
-  return true;
-
 }
 
-void GeniusLyricsProvider::CancelSearch(const int id) { Q_UNUSED(id); }
-
 void GeniusLyricsProvider::HandleSearchReply(QNetworkReply *reply, const int id) {
 
+  Q_ASSERT(QThread::currentThread() != qApp->thread());
+
   if (!replies_.contains(reply)) return;
   replies_.removeAll(reply);
   QObject::disconnect(reply, nullptr, this, nullptr);
@@ -439,6 +467,8 @@ void GeniusLyricsProvider::HandleSearchReply(QNetworkReply *reply, const int id)
 
 void GeniusLyricsProvider::HandleLyricReply(QNetworkReply *reply, const int search_id, const QUrl &url) {
 
+  Q_ASSERT(QThread::currentThread() != qApp->thread());
+
   if (!replies_.contains(reply)) return;
   replies_.removeAll(reply);
   QObject::disconnect(reply, nullptr, this, nullptr);

src/lyrics/geniuslyricsprovider.h

@@ -32,6 +32,7 @@
 #include <QUrl>
 #include <QSslError>
 #include <QJsonArray>
+#include <QMutex>
 
 #include "core/shared_ptr.h"
 #include "jsonlyricsprovider.h"
@@ -49,12 +50,12 @@ class GeniusLyricsProvider : public JsonLyricsProvider {
   explicit GeniusLyricsProvider(SharedPtr<NetworkAccessManager> network, QObject *parent = nullptr);
   ~GeniusLyricsProvider() override;
 
-  bool IsAuthenticated() const override { return !access_token_.isEmpty(); }
+  bool IsAuthenticated() const override { return !access_token().isEmpty(); }
   void Authenticate() override;
-  void Deauthenticate() override { access_token_.clear(); }
+  void Deauthenticate() override { clear_access_token(); }
 
-  bool StartSearch(const int id, const LyricsSearchRequest &request) override;
+ protected Q_SLOTS:
-  void CancelSearch(const int id) override;
+  void StartSearch(const int id, const LyricsSearchRequest &request) override;
 
  private:
   struct GeniusLyricsLyricContext {
@@ -74,6 +75,9 @@ class GeniusLyricsProvider : public JsonLyricsProvider {
   using GeniusLyricsSearchContextPtr = SharedPtr<GeniusLyricsSearchContext>;
 
  private:
+  QString access_token() const;
+  void clear_access_token();
+  void set_access_token(const QString &access_token);
   void RequestAccessToken(const QUrl &url, const QUrl &redirect_url);
   void AuthError(const QString &error = QString(), const QVariant &debug = QVariant());
   void Error(const QString &error, const QVariant &debug = QVariant()) override;
@@ -90,6 +94,7 @@ class GeniusLyricsProvider : public JsonLyricsProvider {
   LocalRedirectServer *server_;
   QString code_verifier_;
   QString code_challenge_;
+  mutable QMutex mutex_access_token_;
   QString access_token_;
   QStringList login_errors_;
   QMap<int, SharedPtr<GeniusLyricsSearchContext>> requests_search_;

src/lyrics/htmllyricsprovider.cpp

@@ -19,7 +19,8 @@
 
 #include "config.h"
 
-#include <QObject>
+#include <QApplication>
+#include <QThread>
 #include <QByteArray>
 #include <QVariant>
 #include <QString>
@@ -49,10 +50,20 @@ HtmlLyricsProvider::~HtmlLyricsProvider() {
 
 }
 
-bool HtmlLyricsProvider::StartSearch(const int id, const LyricsSearchRequest &request) {
+bool HtmlLyricsProvider::StartSearchAsync(const int id, const LyricsSearchRequest &request) {
 
   if (request.artist.isEmpty() || request.title.isEmpty()) return false;
 
+  QMetaObject::invokeMethod(this, "StartSearch", Qt::QueuedConnection, Q_ARG(int, id), Q_ARG(LyricsSearchRequest, request));
+
+  return true;
+
+}
+
+void HtmlLyricsProvider::StartSearch(const int id, const LyricsSearchRequest &request) {
+
+  Q_ASSERT(QThread::currentThread() != qApp->thread());
+
   QUrl url(Url(request));
   QNetworkRequest req(url);
   req.setAttribute(QNetworkRequest::RedirectPolicyAttribute, QNetworkRequest::NoLessSafeRedirectPolicy);
@@ -63,14 +74,12 @@ bool HtmlLyricsProvider::StartSearch(const int id, const LyricsSearchRequest &re
 
   qLog(Debug) << name_ << "Sending request for" << url;
 
-  return true;
-
 }
 
-void HtmlLyricsProvider::CancelSearch(const int id) { Q_UNUSED(id); }
-
 void HtmlLyricsProvider::HandleLyricsReply(QNetworkReply *reply, const int id, const LyricsSearchRequest &request) {
 
+  Q_ASSERT(QThread::currentThread() != qApp->thread());
+
   if (!replies_.contains(reply)) return;
   replies_.removeAll(reply);
   QObject::disconnect(reply, nullptr, this, nullptr);
@@ -116,6 +125,8 @@ void HtmlLyricsProvider::HandleLyricsReply(QNetworkReply *reply, const int id, c
 
 QString HtmlLyricsProvider::ParseLyricsFromHTML(const QString &content, const QRegularExpression &start_tag, const QRegularExpression &end_tag, const QRegularExpression &lyrics_start, const bool multiple) {
 
+  Q_ASSERT(QThread::currentThread() != qApp->thread());
+
   QString lyrics;
   qint64 start_idx = 0;
 

src/lyrics/htmllyricsprovider.h

@@ -43,8 +43,7 @@ class HtmlLyricsProvider : public LyricsProvider {
   explicit HtmlLyricsProvider(const QString &name, const bool enabled, const QString &start_tag, const QString &end_tag, const QString &lyrics_start, const bool multiple, SharedPtr<NetworkAccessManager> network, QObject *parent);
   ~HtmlLyricsProvider();
 
-  virtual bool StartSearch(const int id, const LyricsSearchRequest &request) override;
+  virtual bool StartSearchAsync(const int id, const LyricsSearchRequest &request) override;
-  virtual void CancelSearch(const int id) override;
 
   static QString ParseLyricsFromHTML(const QString &content, const QRegularExpression &start_tag, const QRegularExpression &end_tag, const QRegularExpression &lyrics_start, const bool multiple);
 
@@ -53,6 +52,7 @@ class HtmlLyricsProvider : public LyricsProvider {
   void Error(const QString &error, const QVariant &debug = QVariant()) override;
 
  protected Q_SLOTS:
+  virtual void StartSearch(const int id, const LyricsSearchRequest &request) override;
   virtual void HandleLyricsReply(QNetworkReply *reply, const int id, const LyricsSearchRequest &request);
 
  protected:

src/lyrics/jsonlyricsprovider.cpp

@@ -19,7 +19,6 @@
 
 #include "config.h"
 
-#include <QObject>
 #include <QByteArray>
 #include <QString>
 #include <QNetworkRequest>

src/lyrics/letraslyricsprovider.cpp

@@ -17,7 +17,8 @@
  *
  */
 
-#include <QObject>
+#include <QApplication>
+#include <QThread>
 #include <QString>
 #include <QUrl>
 #include <QRegularExpression>
@@ -47,6 +48,8 @@ QUrl LetrasLyricsProvider::Url(const LyricsSearchRequest &request) {
 
 QString LetrasLyricsProvider::StringFixup(const QString &text) {
 
+  Q_ASSERT(QThread::currentThread() != qApp->thread());
+
   static const QRegularExpression regex_illegal_characters(QStringLiteral("[^\\w0-9_,&\\-\\(\\) ]"));
   static const QRegularExpression regex_multiple_whitespaces(QStringLiteral(" {2,}"));
 

src/lyrics/lololyricsprovider.cpp

@@ -19,7 +19,8 @@
 
 #include "config.h"
 
-#include <QObject>
+#include <QApplication>
+#include <QThread>
 #include <QByteArray>
 #include <QVariant>
 #include <QString>
@@ -54,7 +55,9 @@ LoloLyricsProvider::~LoloLyricsProvider() {
 
 }
 
-bool LoloLyricsProvider::StartSearch(const int id, const LyricsSearchRequest &request) {
+void LoloLyricsProvider::StartSearch(const int id, const LyricsSearchRequest &request) {
+
+  Q_ASSERT(QThread::currentThread() != qApp->thread());
 
   QUrlQuery url_query;
   url_query.addQueryItem(QStringLiteral("artist"), QString::fromLatin1(QUrl::toPercentEncoding(request.artist)));
@@ -68,12 +71,8 @@ bool LoloLyricsProvider::StartSearch(const int id, const LyricsSearchRequest &re
   replies_ << reply;
   QObject::connect(reply, &QNetworkReply::finished, this, [this, reply, id, request]() { HandleSearchReply(reply, id, request); });
 
-  return true;
-
 }
 
-void LoloLyricsProvider::CancelSearch(const int id) { Q_UNUSED(id); }
-
 void LoloLyricsProvider::HandleSearchReply(QNetworkReply *reply, const int id, const LyricsSearchRequest &request) {
 
   if (!replies_.contains(reply)) return;

src/lyrics/lololyricsprovider.h

@@ -42,13 +42,11 @@ class LoloLyricsProvider : public LyricsProvider {
   explicit LoloLyricsProvider(SharedPtr<NetworkAccessManager> network, QObject *parent = nullptr);
   ~LoloLyricsProvider() override;
 
-  bool StartSearch(const int id, const LyricsSearchRequest &request) override;
-  void CancelSearch(const int id) override;
-
  private:
   void Error(const QString &error, const QVariant &debug = QVariant()) override;
 
  private Q_SLOTS:
+  void StartSearch(const int id, const LyricsSearchRequest &request) override;
   void HandleSearchReply(QNetworkReply *reply, const int id, const LyricsSearchRequest &request);
 
  private:

src/lyrics/lyricfindlyricsprovider.cpp

@@ -19,6 +19,8 @@
 
 #include "config.h"
 
+#include <QApplication>
+#include <QThread>
 #include <QByteArray>
 #include <QVariant>
 #include <QString>
@@ -62,6 +64,8 @@ QUrl LyricFindLyricsProvider::Url(const LyricsSearchRequest &request) {
 
 QString LyricFindLyricsProvider::StringFixup(const QString &text) {
 
+  Q_ASSERT(QThread::currentThread() != qApp->thread());
+
   static const QRegularExpression regex_illegal_characters(QStringLiteral("[^\\w0-9_\\- ]"));
   static const QRegularExpression regex_multiple_whitespaces(QStringLiteral(" {2,}"));
 
@@ -74,7 +78,9 @@ QString LyricFindLyricsProvider::StringFixup(const QString &text) {
 
 }
 
-bool LyricFindLyricsProvider::StartSearch(const int id, const LyricsSearchRequest &request) {
+void LyricFindLyricsProvider::StartSearch(const int id, const LyricsSearchRequest &request) {
+
+  Q_ASSERT(QThread::currentThread() != qApp->thread());
 
   const QUrl url = Url(request);
   QNetworkRequest req(url);
@@ -86,14 +92,12 @@ bool LyricFindLyricsProvider::StartSearch(const int id, const LyricsSearchReques
 
   qLog(Debug) << "LyricFind: Sending request for" << url;
 
-  return true;
-
 }
 
-void LyricFindLyricsProvider::CancelSearch(const int id) { Q_UNUSED(id); }
-
 void LyricFindLyricsProvider::HandleSearchReply(QNetworkReply *reply, const int id, const LyricsSearchRequest &request) {
 
+  Q_ASSERT(QThread::currentThread() != qApp->thread());
+
   if (!replies_.contains(reply)) return;
   replies_.removeAll(reply);
   QObject::disconnect(reply, nullptr, this, nullptr);

src/lyrics/lyricfindlyricsprovider.h

@@ -42,14 +42,12 @@ class LyricFindLyricsProvider : public JsonLyricsProvider {
   explicit LyricFindLyricsProvider(SharedPtr<NetworkAccessManager> network, QObject *parent = nullptr);
   ~LyricFindLyricsProvider() override;
 
-  bool StartSearch(const int id, const LyricsSearchRequest &request) override;
-  void CancelSearch(const int id) override;
-
  private:
   static QUrl Url(const LyricsSearchRequest &request);
   static QString StringFixup(const QString &text);
-  void Error(const QString &error, const QVariant &debug = QVariant()) override;
+  void StartSearch(const int id, const LyricsSearchRequest &request) override;
   void EndSearch(const int id, const LyricsSearchRequest &request, const LyricsSearchResults &lyrics = LyricsSearchResults());
+  void Error(const QString &error, const QVariant &debug = QVariant()) override;
 
  private Q_SLOTS:
   void HandleSearchReply(QNetworkReply *reply, const int id, const LyricsSearchRequest &request);

src/lyrics/lyricsfetcher.cpp

@@ -22,7 +22,6 @@
 #include <chrono>
 
 #include <QtGlobal>
-#include <QObject>
 #include <QTimer>
 #include <QString>
 

src/lyrics/lyricsfetchersearch.cpp

@@ -22,7 +22,6 @@
 #include <algorithm>
 #include <utility>
 
-#include <QObject>
 #include <QTimer>
 #include <QList>
 
@@ -54,7 +53,7 @@ void LyricsFetcherSearch::TerminateSearch() {
 
   const QList<int> keys = pending_requests_.keys();
   for (const int id : keys) {
-    pending_requests_.take(id)->CancelSearch(id);
+    pending_requests_.take(id)->CancelSearchAsync(id);
   }
   AllProvidersFinished();
 
@@ -75,7 +74,7 @@ void LyricsFetcherSearch::Start(SharedPtr<LyricsProviders> lyrics_providers) {
     if (!provider->is_enabled() || !provider->IsAuthenticated()) continue;
     QObject::connect(provider, &LyricsProvider::SearchFinished, this, &LyricsFetcherSearch::ProviderSearchFinished);
     const int id = lyrics_providers->NextId();
-    const bool success = provider->StartSearch(id, request_);
+    const bool success = provider->StartSearchAsync(id, request_);
     if (success) {
       pending_requests_.insert(id, provider);
     }

src/lyrics/lyricsprovider.cpp

@@ -19,7 +19,6 @@
 
 #include "config.h"
 
-#include <QObject>
 #include <QString>
 
 #include "core/shared_ptr.h"
@@ -28,3 +27,11 @@
 
 LyricsProvider::LyricsProvider(const QString &name, const bool enabled, const bool authentication_required, SharedPtr<NetworkAccessManager> network, QObject *parent)
     : QObject(parent), network_(network), name_(name), enabled_(enabled), order_(0), authentication_required_(authentication_required) {}
+
+bool LyricsProvider::StartSearchAsync(const int id, const LyricsSearchRequest &request) {
+
+  QMetaObject::invokeMethod(this, "StartSearch", Qt::QueuedConnection, Q_ARG(int, id), Q_ARG(LyricsSearchRequest, request));
+
+  return true;
+
+}

src/lyrics/lyricsprovider.h

@@ -47,8 +47,8 @@ class LyricsProvider : public QObject {
   void set_enabled(const bool enabled) { enabled_ = enabled; }
   void set_order(const int order) { order_ = order; }
 
-  virtual bool StartSearch(const int id, const LyricsSearchRequest &request) = 0;
+  virtual bool StartSearchAsync(const int id, const LyricsSearchRequest &request);
-  virtual void CancelSearch(const int id) { Q_UNUSED(id); }
+  virtual void CancelSearchAsync(const int id) { Q_UNUSED(id); }
   virtual bool AuthenticationRequired() const { return authentication_required_; }
   virtual void Authenticate() {}
   virtual bool IsAuthenticated() const { return !authentication_required_; }
@@ -56,6 +56,9 @@ class LyricsProvider : public QObject {
 
   virtual void Error(const QString &error, const QVariant &debug = QVariant()) = 0;
 
+ protected Q_SLOTS:
+  virtual void StartSearch(const int id, const LyricsSearchRequest &request) = 0;
+
  Q_SIGNALS:
   void AuthenticationComplete(const bool success, const QStringList &errors = QStringList());
   void AuthenticationSuccess();

src/lyrics/lyricsproviders.cpp

@@ -20,8 +20,8 @@
 #include "config.h"
 
 #include <utility>
+#include <memory>
 
-#include <QObject>
 #include <QMutex>
 #include <QList>
 #include <QMap>
@@ -31,6 +31,7 @@
 
 #include "core/logging.h"
 #include "core/settings.h"
+#include "core/networkaccessmanager.h"
 
 #include "lyricsprovider.h"
 #include "lyricsproviders.h"
@@ -39,7 +40,14 @@
 
 int LyricsProviders::NextOrderId = 0;
 
-LyricsProviders::LyricsProviders(QObject *parent) : QObject(parent) {}
+using std::make_shared;
+
+LyricsProviders::LyricsProviders(QObject *parent) : QObject(parent), thread_(new QThread(this)), network_(make_shared<NetworkAccessManager>()) {
+
+  network_->moveToThread(thread_);
+  thread_->start();
+
+}
 
 LyricsProviders::~LyricsProviders() {
 
@@ -47,6 +55,9 @@ LyricsProviders::~LyricsProviders() {
     delete lyrics_providers_.firstKey();
   }
 
+  thread_->quit();
+  thread_->wait(1000);
+
 }
 
 void LyricsProviders::ReloadSettings() {
@@ -96,6 +107,8 @@ LyricsProvider *LyricsProviders::ProviderByName(const QString &name) const {
 
 void LyricsProviders::AddProvider(LyricsProvider *provider) {
 
+  provider->moveToThread(thread_);
+
   {
     QMutexLocker locker(&mutex_);
     lyrics_providers_.insert(provider, provider->name());

src/lyrics/lyricsproviders.h

@@ -29,7 +29,11 @@
 #include <QMap>
 #include <QString>
 #include <QAtomicInt>
+#include <QThread>
 
+#include "core/shared_ptr.h"
+
+class NetworkAccessManager;
 class LyricsProvider;
 
 class LyricsProviders : public QObject {
@@ -39,6 +43,8 @@ class LyricsProviders : public QObject {
   explicit LyricsProviders(QObject *parent = nullptr);
   ~LyricsProviders() override;
 
+  SharedPtr<NetworkAccessManager> network() const { return network_; }
+
   void ReloadSettings();
   LyricsProvider *ProviderByName(const QString &name) const;
 
@@ -56,6 +62,9 @@ class LyricsProviders : public QObject {
 
   static int NextOrderId;
 
+  QThread *thread_;
+  SharedPtr<NetworkAccessManager> network_;
+
   QMap<LyricsProvider*, QString> lyrics_providers_;
   QList<LyricsProvider*> ordered_providers_;
   QMutex mutex_;

src/lyrics/musixmatchlyricsprovider.cpp

@@ -22,7 +22,8 @@
 #include <utility>
 #include <memory>
 
-#include <QObject>
+#include <QApplication>
+#include <QThread>
 #include <QByteArray>
 #include <QVariant>
 #include <QString>
@@ -59,7 +60,9 @@ MusixmatchLyricsProvider::~MusixmatchLyricsProvider() {
 
 }
 
-bool MusixmatchLyricsProvider::StartSearch(const int id, const LyricsSearchRequest &request) {
+void MusixmatchLyricsProvider::StartSearch(const int id, const LyricsSearchRequest &request) {
+
+  Q_ASSERT(QThread::currentThread() != qApp->thread());
 
   LyricsSearchContextPtr search = make_shared<LyricsSearchContext>();
   search->id = id;
@@ -67,15 +70,14 @@ bool MusixmatchLyricsProvider::StartSearch(const int id, const LyricsSearchReque
   requests_search_.append(search);
 
   if (use_api_) {
-    return SendSearchRequest(search);
+    SendSearchRequest(search);
+    return;
   }
 
-  return CreateLyricsRequest(search);
+  CreateLyricsRequest(search);
 
 }
 
-void MusixmatchLyricsProvider::CancelSearch(const int id) { Q_UNUSED(id); }
-
 bool MusixmatchLyricsProvider::SendSearchRequest(LyricsSearchContextPtr search) {
 
   QUrlQuery url_query;
@@ -100,6 +102,8 @@ bool MusixmatchLyricsProvider::SendSearchRequest(LyricsSearchContextPtr search)
 
 void MusixmatchLyricsProvider::HandleSearchReply(QNetworkReply *reply, LyricsSearchContextPtr search) {
 
+  Q_ASSERT(QThread::currentThread() != qApp->thread());
+
   if (!replies_.contains(reply)) return;
   replies_.removeAll(reply);
   QObject::disconnect(reply, nullptr, this, nullptr);
@@ -274,6 +278,8 @@ bool MusixmatchLyricsProvider::SendLyricsRequest(LyricsSearchContextPtr search,
 
 void MusixmatchLyricsProvider::HandleLyricsReply(QNetworkReply *reply, LyricsSearchContextPtr search, const QUrl &url) {
 
+  Q_ASSERT(QThread::currentThread() != qApp->thread());
+
   if (!replies_.contains(reply)) return;
   replies_.removeAll(reply);
   QObject::disconnect(reply, nullptr, this, nullptr);

src/lyrics/musixmatchlyricsprovider.h

@@ -45,9 +45,6 @@ class MusixmatchLyricsProvider : public JsonLyricsProvider, public MusixmatchPro
   explicit MusixmatchLyricsProvider(SharedPtr<NetworkAccessManager> network, QObject *parent = nullptr);
   ~MusixmatchLyricsProvider() override;
 
-  bool StartSearch(const int id, const LyricsSearchRequest &request) override;
-  void CancelSearch(const int id) override;
-
  private:
   struct LyricsSearchContext {
     explicit LyricsSearchContext() : id(-1) {}
@@ -66,6 +63,9 @@ class MusixmatchLyricsProvider : public JsonLyricsProvider, public MusixmatchPro
   void EndSearch(LyricsSearchContextPtr search, const QUrl &url = QUrl());
   void Error(const QString &error, const QVariant &debug = QVariant()) override;
 
+ protected Q_SLOTS:
+  void StartSearch(const int id, const LyricsSearchRequest &request) override;
+
  private Q_SLOTS:
   void HandleSearchReply(QNetworkReply *reply, MusixmatchLyricsProvider::LyricsSearchContextPtr search);
   void HandleLyricsReply(QNetworkReply *reply, MusixmatchLyricsProvider::LyricsSearchContextPtr search, const QUrl &url);

src/lyrics/ovhlyricsprovider.cpp

@@ -19,7 +19,8 @@
 
 #include "config.h"
 
-#include <QObject>
+#include <QApplication>
+#include <QThread>
 #include <QVariant>
 #include <QString>
 #include <QUrl>
@@ -53,7 +54,9 @@ OVHLyricsProvider::~OVHLyricsProvider() {
 
 }
 
-bool OVHLyricsProvider::StartSearch(const int id, const LyricsSearchRequest &request) {
+void OVHLyricsProvider::StartSearch(const int id, const LyricsSearchRequest &request) {
+
+  Q_ASSERT(QThread::currentThread() != qApp->thread());
 
   QUrl url(QString::fromLatin1(kUrlSearch) + QString::fromLatin1(QUrl::toPercentEncoding(request.artist)) + QLatin1Char('/') + QString::fromLatin1(QUrl::toPercentEncoding(request.title)));
   QNetworkRequest req(url);
@@ -62,12 +65,8 @@ bool OVHLyricsProvider::StartSearch(const int id, const LyricsSearchRequest &req
   replies_ << reply;
   QObject::connect(reply, &QNetworkReply::finished, this, [this, reply, id, request]() { HandleSearchReply(reply, id, request); });
 
-  return true;
-
 }
 
-void OVHLyricsProvider::CancelSearch(const int id) { Q_UNUSED(id); }
-
 void OVHLyricsProvider::HandleSearchReply(QNetworkReply *reply, const int id, const LyricsSearchRequest &request) {
 
   if (!replies_.contains(reply)) return;

src/lyrics/ovhlyricsprovider.h

@@ -42,12 +42,12 @@ class OVHLyricsProvider : public JsonLyricsProvider {
   explicit OVHLyricsProvider(SharedPtr<NetworkAccessManager> network, QObject *parent = nullptr);
   ~OVHLyricsProvider() override;
 
-  bool StartSearch(const int id, const LyricsSearchRequest &request) override;
-  void CancelSearch(const int id) override;
-
  private:
   void Error(const QString &error, const QVariant &debug = QVariant()) override;
 
+ protected Q_SLOTS:
+  void StartSearch(const int id, const LyricsSearchRequest &request) override;
+
  private Q_SLOTS:
   void HandleSearchReply(QNetworkReply *reply, const int id, const LyricsSearchRequest &request);
 

src/lyrics/songlyricscomlyricsprovider.cpp

@@ -17,7 +17,8 @@
  *
  */
 
-#include <QObject>
+#include <QApplication>
+#include <QThread>
 #include <QString>
 #include <QUrl>
 #include <QRegularExpression>
@@ -45,6 +46,8 @@ QUrl SongLyricsComLyricsProvider::Url(const LyricsSearchRequest &request) {
 
 QString SongLyricsComLyricsProvider::StringFixup(QString text) {
 
+  Q_ASSERT(QThread::currentThread() != qApp->thread());
+
   static const QRegularExpression regex_illegal_characters(QStringLiteral("[^\\w0-9\\- ]"));
   static const QRegularExpression regex_multiple_whitespaces(QStringLiteral(" {2,}"));
   static const QRegularExpression regex_multiple_dashes(QStringLiteral("(-)\\1+"));