Stop scanning the library straight away if we're asked to quit. Fixes issue #114

src/albumcoverloader.cpp

@@ -24,6 +24,7 @@ const char* AlbumCoverLoader::kManuallyUnsetCover = "(unset)";
 
 AlbumCoverLoader::AlbumCoverLoader(QObject* parent)
   : QObject(parent),
+    stop_requested_(false),
     height_(120),
     next_id_(0)
 {
@@ -58,6 +59,8 @@ quint64 AlbumCoverLoader::LoadImageAsync(const QString& art_automatic,
 
 void AlbumCoverLoader::ProcessTasks() {
   forever {
+    if (stop_requested_) return;
+
     // Get the next task
     Task task;
     {

src/albumcoverloader.h

@@ -29,6 +29,8 @@ class AlbumCoverLoader : public QObject {
 
  public:
   AlbumCoverLoader(QObject* parent = 0);
+  
+  void Stop() { stop_requested_ = true; }
 
   static QString ImageCacheDir();
 
@@ -55,6 +57,8 @@ class AlbumCoverLoader : public QObject {
     QString art_manual;
   };
 
+  bool stop_requested_;
+
   int height_;
 
   QMutex mutex_;

src/backgroundthread.h

@@ -137,6 +137,9 @@ BackgroundThread<InterfaceType>::BackgroundThread(QObject *parent)
 template <typename InterfaceType>
 BackgroundThread<InterfaceType>::~BackgroundThread() {
   if (isRunning()) {
+    if (worker_) // Possible race condition here
+      worker_->Stop();
+
     quit();
     if (wait(10000))
       return;

src/librarybackend.h

@@ -52,6 +52,8 @@ class LibraryBackendInterface : public QObject {
   };
   typedef QList<Album> AlbumList;
 
+  virtual void Stop() {};
+
   // Get a list of directories in the library.  Emits DirectoriesDiscovered.
   virtual void LoadDirectoriesAsync() = 0;
 

src/librarywatcher.cpp

@@ -31,6 +31,7 @@
 
 LibraryWatcher::LibraryWatcher(QObject* parent)
   : QObject(parent),
+    stop_requested_(false),
     fs_watcher_(new QFileSystemWatcher(this)),
     rescan_timer_(new QTimer(this)),
     total_watches_(0)
@@ -47,8 +48,10 @@ void LibraryWatcher::AddDirectories(const DirectoryList& directories) {
   // could be music.
 
   foreach (const Directory& dir, directories) {
+    if (stop_requested_) return;
     paths_watched_[dir.path] = dir;
     ScanDirectory(dir.path);
+    if (stop_requested_) return;
 
     // Start monitoring this directory for more changes
     fs_watcher_->addPath(dir.path);
@@ -118,6 +121,8 @@ void LibraryWatcher::ScanDirectory(const QString& path) {
       album_art[dir] << path;
     else if (engine_->canDecode(QUrl::fromLocalFile(path)))
       files_on_disk << path;
+
+    if (stop_requested_) return;
   }
 
   // Ask the database for a list of files in this directory
@@ -127,6 +132,8 @@ void LibraryWatcher::ScanDirectory(const QString& path) {
   SongList new_songs;
   SongList touched_songs;
   foreach (const QString& file, files_on_disk) {
+    if (stop_requested_) return;
+
     Song matching_song;
     if (FindSongByPath(songs_in_db, file, &matching_song)) {
       // The song is in the database and still on disk.
@@ -185,6 +192,8 @@ void LibraryWatcher::ScanDirectory(const QString& path) {
     }
   }
 
+  if (stop_requested_) return;
+
   if (!new_songs.isEmpty())
     emit NewOrUpdatedSongs(new_songs);
 
@@ -200,6 +209,8 @@ void LibraryWatcher::ScanDirectory(const QString& path) {
     }
   }
 
+  if (stop_requested_) return;
+
   if (!deleted_songs.isEmpty())
     emit SongsDeleted(deleted_songs);
 
@@ -226,8 +237,11 @@ void LibraryWatcher::DirectoryChanged(const QString &path) {
 }
 
 void LibraryWatcher::RescanPathsNow() {
-  foreach (const QString& path, paths_needing_rescan_)
+  foreach (const QString& path, paths_needing_rescan_) {
+    if (stop_requested_) return;
     ScanDirectory(path);
+  }
+
   paths_needing_rescan_.clear();
 
   qDebug() << "Updating compilations...";

src/librarywatcher.h

@@ -41,6 +41,8 @@ class LibraryWatcher : public QObject {
   void SetBackend(boost::shared_ptr<LibraryBackendInterface> backend) { backend_ = backend; }
   void SetEngine(EngineBase* engine) { engine_ = engine; } // TODO: shared_ptr
 
+  void Stop() { stop_requested_ = true; }
+
  signals:
   void NewOrUpdatedSongs(const SongList& songs);
   void SongsMTimeUpdated(const SongList& songs);
@@ -68,6 +70,7 @@ class LibraryWatcher : public QObject {
  private:
   EngineBase* engine_;
   boost::shared_ptr<LibraryBackendInterface> backend_;
+  bool stop_requested_;
 
   QFileSystemWatcher* fs_watcher_;
   QTimer* rescan_timer_;