Update issue 1175:

Add an option in preferences to save all ratings/statistics into files, for all songs

src/core/tagreaderclient.cpp

@@ -147,6 +147,20 @@ bool TagReaderClient::SaveFileBlocking(const QString& filename, const Song& meta
   return ret;
 }
 
+bool TagReaderClient::UpdateSongStatisticsBlocking(const Song& metadata) {
+  Q_ASSERT(QThread::currentThread() != thread());
+
+  bool ret = false;
+
+  TagReaderReply* reply = UpdateSongStatistics(metadata);
+  if (reply->WaitForFinished()) {
+    ret = reply->message().save_song_statistics_to_file_response().success();
+  }
+  reply->deleteLater();
+
+  return ret;
+}
+
 bool TagReaderClient::IsMediaFileBlocking(const QString& filename) {
   Q_ASSERT(QThread::currentThread() != thread());
 

src/core/tagreaderclient.h

@@ -57,6 +57,7 @@ public:
   // be called from the TagReaderClient's thread.
   void ReadFileBlocking(const QString& filename, Song* song);
   bool SaveFileBlocking(const QString& filename, const Song& metadata);
+  bool UpdateSongStatisticsBlocking(const Song& metadata);
   bool IsMediaFileBlocking(const QString& filename);
   QImage LoadEmbeddedArtBlocking(const QString& filename);
 

src/library/library.cpp

@@ -21,6 +21,8 @@
 #include "librarybackend.h"
 #include "core/application.h"
 #include "core/database.h"
+#include "core/tagreaderclient.h"
+#include "core/taskmanager.h"
 #include "smartplaylists/generator.h"
 #include "smartplaylists/querygenerator.h"
 #include "smartplaylists/search.h"
@@ -155,3 +157,18 @@ void Library::ReloadSettings() {
   backend_->ReloadSettingsAsync();
   watcher_->ReloadSettingsAsync();
 }
+
+void Library::WriteAllSongsStatisticsToFiles() {
+  const SongList all_songs = backend_->GetAllSongs();
+
+  const int task_id = app_->task_manager()->StartTask(tr("Saving songs statistics into songs files"));
+  app_->task_manager()->SetTaskBlocksLibraryScans(task_id);
+
+  const int nb_songs = all_songs.size();
+  int i = 0;
+  foreach (const Song& song, all_songs) {
+    TagReaderClient::Instance()->UpdateSongStatisticsBlocking(song);
+    app_->task_manager()->SetTaskProgress(task_id, ++i, nb_songs);
+  }
+  app_->task_manager()->SetTaskFinished(task_id);
+}

src/library/library.h

@@ -49,6 +49,8 @@ class Library : public QObject {
 
   QString full_rescan_reason(int schema_version) const { return full_rescan_revisions_.value(schema_version, QString()); }
 
+  void WriteAllSongsStatisticsToFiles();
+
  public slots:
   void ReloadSettings();
 

src/library/librarybackend.cpp

@@ -964,6 +964,13 @@ SongList LibraryBackend::FindSongs(const smart_playlists::Search& search) {
   return ret;
 }
 
+SongList LibraryBackend::GetAllSongs() {
+  // Get all the songs!
+  return FindSongs(smart_playlists::Search(
+      smart_playlists::Search::Type_All, smart_playlists::Search::TermList(),
+      smart_playlists::Search::Sort_FieldAsc, smart_playlists::SearchTerm::Field_Artist, -1));
+}
+
 void LibraryBackend::IncrementPlayCount(int id) {
   if (id == -1)
     return;

src/library/librarybackend.h

@@ -157,6 +157,7 @@ class LibraryBackend : public LibraryBackendInterface {
   bool ExecQuery(LibraryQuery* q);
   SongList ExecLibraryQuery(LibraryQuery* query);
   SongList FindSongs(const smart_playlists::Search& search);
+  SongList GetAllSongs();
 
   void IncrementPlayCountAsync(int id);
   void IncrementSkipCountAsync(int id, float progress);

src/library/librarysettingspage.cpp

@@ -28,9 +28,11 @@
 #include "ui/iconloader.h"
 #include "ui/settingsdialog.h"
 
-#include <QFileDialog>
-#include <QSettings>
 #include <QDir>
+#include <QFileDialog>
+#include <QMessageBox>
+#include <QSettings>
+#include <QtConcurrentRun>
 
 const char* LibrarySettingsPage::kSettingsGroup = "LibraryConfig";
 
@@ -49,6 +51,7 @@ LibrarySettingsPage::LibrarySettingsPage(SettingsDialog* dialog)
 
   connect(ui_->add, SIGNAL(clicked()), SLOT(Add()));
   connect(ui_->remove, SIGNAL(clicked()), SLOT(Remove()));
+  connect(ui_->sync_stats_button, SIGNAL(clicked()), SLOT(WriteAllSongsStatisticsToFiles()));
 }
 
 LibrarySettingsPage::~LibrarySettingsPage() {
@@ -138,3 +141,15 @@ void LibrarySettingsPage::Load() {
   ui_->save_statistics_in_file->setChecked(s.value("save_statistics_in_file", false).toBool());
   s.endGroup();
 }
+
+void LibrarySettingsPage::WriteAllSongsStatisticsToFiles() {
+  QMessageBox confirmation_dialog(
+      QMessageBox::Question,
+      tr("Write all songs statistics into songs' files"),
+      tr("Are you sure you want to write song's statistics into song's file for all the songs of your library?"),
+      QMessageBox::Yes | QMessageBox::Cancel);
+  if (confirmation_dialog.exec() != QMessageBox::Yes) {
+    return;
+  }
+  QtConcurrent::run(dialog()->app()->library(), &Library::WriteAllSongsStatisticsToFiles);
+}

src/library/librarysettingspage.h

@@ -40,6 +40,7 @@ public:
 private slots:
   void Add();
   void Remove();
+  void WriteAllSongsStatisticsToFiles();
 
   void CurrentRowChanged(const QModelIndex& index);
 

src/library/librarysettingspage.ui

@@ -7,7 +7,7 @@
     <x>0</x>
     <y>0</y>
     <width>509</width>
-    <height>395</height>
+    <height>452</height>
    </rect>
   </property>
   <property name="windowTitle">
@@ -102,6 +102,33 @@
         </property>
        </widget>
       </item>
+      <item>
+       <layout class="QHBoxLayout" name="horizontalLayout_5">
+        <item>
+         <widget class="QPushButton" name="sync_stats_button">
+          <property name="toolTip">
+           <string>&lt;html&gt;&lt;head/&gt;&lt;body&gt;&lt;p&gt;This will write songs' ratings and statistics into files tags for all your library's songs.&lt;/p&gt;&lt;p&gt;This is not needed if the &amp;quot;Save ratings and statistics in file tags&amp;quot; option has always been activated.&lt;/p&gt;&lt;/body&gt;&lt;/html&gt;</string>
+          </property>
+          <property name="text">
+           <string>Synchronize statistics to files now</string>
+          </property>
+         </widget>
+        </item>
+        <item>
+         <spacer name="horizontalSpacer">
+          <property name="orientation">
+           <enum>Qt::Horizontal</enum>
+          </property>
+          <property name="sizeHint" stdset="0">
+           <size>
+            <width>40</width>
+            <height>20</height>
+           </size>
+          </property>
+         </spacer>
+        </item>
+       </layout>
+      </item>
       <item>
        <widget class="QLabel" name="label_2">
         <property name="text">