Merge pull request #6533 from jbroadus/inotify-errors

Inotify errors

src/core/filesystemwatcherinterface.h

@@ -27,7 +27,7 @@ class FileSystemWatcherInterface : public QObject {
  public:
   explicit FileSystemWatcherInterface(QObject* parent = nullptr);
   virtual void Init() {}
-  virtual void AddPath(const QString& path) = 0;
+  virtual bool AddPath(const QString& path) = 0;
   virtual void RemovePath(const QString& path) = 0;
   virtual void Clear() = 0;
 

src/core/macfslistener.h

@@ -35,7 +35,7 @@ class MacFSListener : public FileSystemWatcherInterface {
  public:
   explicit MacFSListener(QObject* parent = nullptr);
   void Init();
-  void AddPath(const QString& path);
+  bool AddPath(const QString& path);
   void RemovePath(const QString& path);
   void Clear();
 

src/core/macfslistener.mm

@@ -52,10 +52,11 @@ void MacFSListener::EventStreamCallback(
   }
 }
 
-void MacFSListener::AddPath(const QString& path) {
+bool MacFSListener::AddPath(const QString& path) {
   Q_ASSERT(run_loop_);
   paths_.insert(path);
   UpdateStreamAsync();
+  return true;
 }
 
 void MacFSListener::RemovePath(const QString& path) {

src/core/qtfslistener.cpp

@@ -27,7 +27,9 @@ QtFSListener::QtFSListener(QObject* parent)
           SIGNAL(PathChanged(const QString&)));
 }
 
-void QtFSListener::AddPath(const QString& path) { watcher_.addPath(path); }
+bool QtFSListener::AddPath(const QString& path) {
+  return watcher_.addPath(path);
+}
 
 void QtFSListener::RemovePath(const QString& path) {
   watcher_.removePath(path);

src/core/qtfslistener.h

@@ -28,7 +28,7 @@ class QtFSListener : public FileSystemWatcherInterface {
   Q_OBJECT
  public:
   explicit QtFSListener(QObject* parent);
-  virtual void AddPath(const QString& path);
+  virtual bool AddPath(const QString& path);
   virtual void RemovePath(const QString& path);
   virtual void Clear();
 

src/devices/filesystemdevice.cpp

@@ -64,6 +64,7 @@ FilesystemDevice::FilesystemDevice(const QUrl& url, DeviceLister* lister,
   connect(watcher_, SIGNAL(CompilationsNeedUpdating()), backend_.get(),
           SLOT(UpdateCompilations()));
   connect(watcher_, SIGNAL(ScanStarted(int)), SIGNAL(TaskStarted(int)));
+  connect(watcher_, &LibraryWatcher::Error, app, &Application::AddError);
 }
 
 void FilesystemDevice::Init() {

src/library/library.cpp

@@ -161,6 +161,7 @@ void Library::Init() {
           backend_.get(), SLOT(AddOrUpdateSubdirs(SubdirectoryList)));
   connect(watcher_, SIGNAL(CompilationsNeedUpdating()), backend_.get(),
           SLOT(UpdateCompilations()));
+  connect(watcher_, &LibraryWatcher::Error, app_, &Application::AddError);
   connect(app_->playlist_manager(), SIGNAL(CurrentSongChanged(Song)),
           SLOT(CurrentSongChanged(Song)));
   connect(app_->player(), SIGNAL(Stopped()), SLOT(Stopped()));

src/library/librarywatcher.cpp

@@ -588,11 +588,34 @@ uint LibraryWatcher::GetMtimeForCue(const QString& cue_path) {
 }
 
 void LibraryWatcher::AddWatch(const Directory& dir, const QString& path) {
-  if (!QFile::exists(path)) return;
+  QFileInfo info(path);
+  if (!info.exists() || !info.isReadable()) return;
 
   connect(fs_watcher_, SIGNAL(PathChanged(const QString&)), this,
           SLOT(DirectoryChanged(const QString&)), Qt::UniqueConnection);
-  fs_watcher_->AddPath(path);
+  if (!fs_watcher_->AddPath(path)) {
+    // Since this may be a system error, don't spam the user.
+    static int errCount = 0;
+    if (errCount++ == 0) {
+#ifdef Q_OS_LINUX
+      // The Linux implementation of QFileSystemWatcher utilizes inotify, so
+      // the limit in /proc/sys/fs/inotify/max_user_watches may be a problem
+      // in large libraries.
+      const char* fmt =
+          "Failed to watch %1\n"
+          "On a Linux system, this may be due to the inotify max_user_watches "
+          "limit.\n\n"
+          "This error will not be shown again during this session.";
+#else
+      const char* fmt =
+          "Failed to watch %1 for unknown reasons.\n\n"
+          "This error will not be shown again during this session.";
+#endif
+      emit Error(tr(fmt).arg(path));
+    }
+    return;
+  }
+
   subdir_mapping_[path] = dir;
 }
 

src/library/librarywatcher.h

@@ -68,6 +68,8 @@ signals:
 
   void ScanStarted(int task_id);
 
+  void Error(const QString& message);
+
  public slots:
   void ReloadSettings();
   void AddDirectory(const Directory& dir, const SubdirectoryList& subdirs);

src/widgets/errordialog.cpp

@@ -55,7 +55,7 @@ void ErrorDialog::UpdateContent() {
   QString html;
   for (const QString& message : current_messages_) {
     if (!html.isEmpty()) html += "<hr/>";
-    html += message.toHtmlEscaped();
+    html += message.toHtmlEscaped().replace("\n", "<br>");
   }
   ui_->messages->setHtml(html);
 }