gui: Introduce PreviewCoordinator

Move some preview generation logic to PreviewCoordinator

gui/previewcoordinator.h

@@ -0,0 +1,48 @@
+#ifndef PREVIEWCOORDINATOR_H
+#define PREVIEWCOORDINATOR_H
+#include <QVector>
+#include <QObject>
+#include <QThread>
+#include "searchresult.h"
+#include "previewresult.h"
+#include "ipcpreviewclient.h"
+#include "rendertarget.h"
+class PreviewCoordinator : public QObject
+{
+	Q_OBJECT
+  private:
+	QThread ipcClientThread;
+	IPCPreviewClient ipcPreviewClient;
+	QString socketPath;
+
+	QVector<QSharedPointer<PreviewResult>> previewResults;
+	QVector<SearchResult> previewableSearchResults;
+
+	unsigned int currentPreviewGeneration = 1;
+
+	/* Quick lookup table for the order a preview should have */
+	QHash<QString, int> previewOrder;
+
+  public:
+	PreviewCoordinator();
+
+	void init(const QVector<SearchResult> &searchResults);
+
+	int previewableCount() const;
+	const QVector<SearchResult> &getPreviewableSearchResults() const;
+
+	QSharedPointer<PreviewResult> resultAt(int index);
+
+	void setSocketPath(QString socketPath);
+  public slots:
+	void startGeneration(RenderConfig config, const QVector<RenderTarget> &targets);
+	void handleReceivedPreview(QSharedPointer<PreviewResult> preview, unsigned int previewGeneration);
+
+  signals:
+	void previewReady();
+	void completedGeneration();
+	void error(QString);
+	void ipcStartGeneration(RenderConfig config, const QVector<RenderTarget> &targets);
+};
+
+#endif // PREVIEWCOORDINATOR_H