Use HttpMetaCache to minimize network use.

logic/net/Download.h

@@ -0,0 +1,54 @@
+#pragma once
+
+#include <QObject>
+#include <QUrl>
+#include <QSharedPointer>
+#include <QNetworkReply>
+
+
+enum JobStatus
+{
+	Job_NotStarted,
+	Job_InProgress,
+	Job_Finished,
+	Job_Failed
+};
+
+class Download : public QObject
+{
+	Q_OBJECT
+protected:
+	explicit Download(): QObject(0){};
+public:
+	virtual ~Download() {};
+
+public:
+	/// the network reply
+	QSharedPointer<QNetworkReply> m_reply;
+	
+	/// source URL
+	QUrl m_url;
+	
+	/// The file's status
+	JobStatus m_status;
+	
+	/// index within the parent job
+	int index_within_job = 0;
+
+signals:
+	void started(int index);
+	void progress(int index, qint64 current, qint64 total);
+	void succeeded(int index);
+	void failed(int index);
+
+protected slots:
+	virtual void downloadProgress(qint64 bytesReceived, qint64 bytesTotal) = 0;
+	virtual void downloadError(QNetworkReply::NetworkError error) = 0;
+	virtual void downloadFinished() = 0;
+	virtual void downloadReadyRead() = 0;
+	
+public slots:
+	virtual void start() = 0;
+};
+
+typedef QSharedPointer<Download> DownloadPtr;