UpdateDialog: implement update download functionality

src/qt/network.h

@@ -1,10 +1,72 @@
+// Copyright (c) 2020, The Monero Project
+//
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without modification, are
+// permitted provided that the following conditions are met:
+//
+// 1. Redistributions of source code must retain the above copyright notice, this list of
+//    conditions and the following disclaimer.
+//
+// 2. Redistributions in binary form must reproduce the above copyright notice, this list
+//    of conditions and the following disclaimer in the documentation and/or other
+//    materials provided with the distribution.
+//
+// 3. Neither the name of the copyright holder nor the names of its contributors may be
+//    used to endorse or promote products derived from this software without specific
+//    prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY
+// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+// MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
+// THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+// STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
+// THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
 #pragma once
 
 #include <QCoreApplication>
 #include <QtNetwork>
 
+// TODO: wallet_merged - epee library triggers the warnings
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wunused-parameter"
+#pragma GCC diagnostic ignored "-Wreorder"
+#include <net/http_client.h>
+#pragma GCC diagnostic pop
+
 #include "FutureScheduler.h"
 
+class HttpClient : public QObject, public epee::net_utils::http::http_simple_client
+{
+    Q_OBJECT
+    Q_PROPERTY(quint64 contentLength READ contentLength NOTIFY contentLengthChanged);
+    Q_PROPERTY(quint64 received READ received NOTIFY receivedChanged);
+
+public:
+    HttpClient(QObject *parent = nullptr);
+
+    void cancel();
+    quint64 contentLength() const;
+    quint64 received() const;
+
+signals:
+    void contentLengthChanged() const;
+    void receivedChanged() const;
+
+protected:
+    bool on_header(const epee::net_utils::http::http_response_info &headers) final;
+    bool handle_target_data(std::string &piece_of_transfer) final;
+
+private:
+    std::atomic<bool> m_cancel;
+    std::atomic<size_t> m_contentLength;
+    std::atomic<size_t> m_received;
+};
+
 class Network : public QObject
 {
     Q_OBJECT
@@ -15,6 +77,12 @@ public:
     Q_INVOKABLE void get(const QString &url, const QJSValue &callback, const QString &contentType = {}) const;
     Q_INVOKABLE void getJSON(const QString &url, const QJSValue &callback) const;
 
+    QString get(
+        std::shared_ptr<epee::net_utils::http::http_simple_client> httpClient,
+        const QString &url,
+        std::string &response,
+        const QString &contentType = {}) const;
+
 private:
     mutable FutureScheduler m_scheduler;
 };