Cloudbrowser: ImageProvider reentrant.

examples/cloudbrowser/Window.cpp

@@ -122,9 +122,7 @@ void Window::onSuccessfullyAuthorized() {
             << cloud_provider_->name().c_str() << "\n";
 }
 
-void Window::onAddedItem(IItem::Pointer i) {
-  directory_model_.addItem(i, this);
-}
+void Window::onAddedItem(ItemPointer i) { directory_model_.addItem(i, this); }
 
 void Window::onPlayFile(QString filename) {
   VLC::Media media(vlc_instance_, QDir::currentPath().toStdString() + "/" +
@@ -225,7 +223,6 @@ void Window::stop() {
   std::cerr << "[DIAG] Trying to stop player\n";
   media_player_.stop();
   std::cerr << "[DIAG] Stopped\n";
-  download_request_ = nullptr;
 }
 
 void Window::uploadFile(QString path) {
@@ -247,27 +244,35 @@ void Window::downloadFile(int item_id, QUrl path) {
 }
 
 ItemModel::ItemModel(IItem::Pointer item, ICloudProvider::Pointer p, Window* w)
-    : item_(item), window_(w) {
+    : item_(item), provider_(p), window_(w) {
   QString id = (p->name() + "/" + item_->id()).c_str();
   connect(this, &ItemModel::receivedImage, [this, id](ImagePointer image) {
     window_->imageProvider()->addImage(id, std::move(image));
     thumbnail_ = "image://provider//" + id;
     emit thumbnailChanged();
   });
+}
 
+void ItemModel::fetchThumbnail() {
+  if (!thumbnail_.isEmpty()) return;
+  QString id = (provider_->name() + "/" + item_->id()).c_str();
   if (window_->imageProvider()->hasImage(id))
     thumbnail_ = "image://provider//" + id;
   else
-    thumbnail_request_ = p->getThumbnailAsync(
-        item, make_unique<DownloadThumbnailCallback>(this));
+    thumbnail_request_ = provider_->getThumbnailAsync(
+        item_, make_unique<DownloadThumbnailCallback>(this));
 }
 
 ImageProvider::ImageProvider() : QQuickImageProvider(Image) {}
 
 QImage ImageProvider::requestImage(const QString& id, QSize* size,
                                    const QSize& requested_size) {
-  if (cache_.find(id) == cache_.end()) return QImage();
-  QImage img = *cache_[id];
+  QImage img;
+  {
+    std::unique_lock<std::mutex> lock(mutex_);
+    if (cache_.find(id) == cache_.end()) return QImage();
+    img = *cache_[id];
+  }
   if (requested_size.isValid())
     img = img.scaled(requested_size.width(), requested_size.height());
   *size = requested_size;
@@ -275,21 +280,29 @@ QImage ImageProvider::requestImage(const QString& id, QSize* size,
 }
 
 void ImageProvider::addImage(QString id, ImagePointer img) {
+  std::unique_lock<std::mutex> lock(mutex_);
   cache_["/" + id] = std::move(img);
 }
 
 bool ImageProvider::hasImage(QString id) {
+  std::unique_lock<std::mutex> lock(mutex_);
   return cache_.find("/" + id) != cache_.end();
 }
 
 int DirectoryModel::rowCount(const QModelIndex&) const { return list_.size(); }
 
 QVariant DirectoryModel::data(const QModelIndex& id, int) const {
+  if (static_cast<uint32_t>(id.row()) >= list_.size()) {
+    std::cerr << "[FAIL] QML requests nonexistent object.\n";
+    return QVariant();
+  }
+  auto model = list_[id.row()].get();
+  model->fetchThumbnail();
+
   QVariantMap dict;
-  dict["thumbnail"] = list_[id.row()]->thumbnail();
-  dict["name"] = list_[id.row()]->item()->filename().c_str();
-  dict["is_directory"] =
-      list_[id.row()]->item()->type() == IItem::FileType::Directory;
+  dict["thumbnail"] = model->thumbnail();
+  dict["name"] = model->item()->filename().c_str();
+  dict["is_directory"] = model->item()->type() == IItem::FileType::Directory;
   return dict;
 }
 

examples/cloudbrowser/Window.h

@@ -47,6 +47,7 @@ class ImageProvider : public QQuickImageProvider {
   bool hasImage(QString id);
 
  private:
+  std::mutex mutex_;
   std::map<QString, ImagePointer> cache_;
 };
 
@@ -54,12 +55,12 @@ class ItemModel : public QObject {
  public:
   using Pointer = std::unique_ptr<ItemModel>;
 
-  ItemModel(cloudstorage::IItem::Pointer item,
-            cloudstorage::ICloudProvider::Pointer, Window*);
+  ItemModel(IItem::Pointer item, ICloudProvider::Pointer, Window*);
 
   QString name() const { return item_->filename().c_str(); }
   cloudstorage::IItem::Pointer item() const { return item_; }
   QString thumbnail() const { return thumbnail_; }
+  void fetchThumbnail();
 
  signals:
   void thumbnailChanged();
@@ -69,8 +70,9 @@ class ItemModel : public QObject {
   friend class Window;
 
   QString thumbnail_;
-  cloudstorage::IItem::Pointer item_;
-  cloudstorage::ICloudProvider::DownloadFileRequest::Pointer thumbnail_request_;
+  IItem::Pointer item_;
+  ICloudProvider::DownloadFileRequest::Pointer thumbnail_request_;
+  ICloudProvider::Pointer provider_;
   Window* window_;
 
   Q_OBJECT
@@ -107,7 +109,7 @@ class Window : public QQuickView {
   Q_INVOKABLE void downloadFile(int, QUrl path);
 
   void onSuccessfullyAuthorized();
-  void onAddedItem(cloudstorage::IItem::Pointer);
+  void onAddedItem(ItemPointer);
   void onPlayFile(QString filename);
   void onPlayFileFromUrl(QString url);
 

examples/cloudbrowser/main.qml

@@ -85,7 +85,7 @@ Item {
                 property int thumbnailWidth: 50
                 property int thumbnailHeight: 50
                 property int padding: 5
-                property string isDirectory: display["is_directory"]
+                property bool isDirectory: display.is_directory
 
                 id: fileEntry
                 height: thumbnailHeight + 2 * padding
@@ -98,7 +98,7 @@ Item {
                     Image {
                         width: fileEntry.thumbnailWidth
                         height: fileEntry.thumbnailHeight
-                        source: display["thumbnail"]
+                        source: display.thumbnail
                     }
                     Item {
                         height: fileEntry.thumbnailHeight
@@ -107,7 +107,7 @@ Item {
                             x: fileEntry.padding
                             id: text
                             anchors.verticalCenter: parent.verticalCenter
-                            text: display["name"]
+                            text: display.name
                         }
                     }
                 }