From 5581cff55b3cebe28458be379bab684ce35ec828 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Martin=20T=C5=AFma?= <tumic@cbox.cz>
Date: Mon, 16 Jan 2017 09:53:01 +0100
Subject: [PATCH] Fixed download error handling in case of redirects Do not
 download tiles multiple times.

---
 src/downloader.cpp | 37 +++++++++++++++++++++++++++----------
 src/downloader.h   |  6 +++---
 2 files changed, 30 insertions(+), 13 deletions(-)

diff --git a/src/downloader.cpp b/src/downloader.cpp
index 2c42d3de..d70ef51b 100644
--- a/src/downloader.cpp
+++ b/src/downloader.cpp
@@ -17,25 +17,32 @@
 #define USER_AGENT \
 	APP_NAME "/" APP_VERSION " (" PLATFORM_STR "; Qt " QT_VERSION_STR ")"
 
+#define ATTR_FILE   QNetworkRequest::User
+#define ATTR_ORIGIN (QNetworkRequest::Attribute)(QNetworkRequest::User + 1)
+
 Downloader::Downloader()
 {
 	connect(&_manager, SIGNAL(finished(QNetworkReply*)),
 			SLOT(downloadFinished(QNetworkReply*)));
 }
 
-bool Downloader::doDownload(const Download &dl)
+bool Downloader::doDownload(const Download &dl, const QUrl &origin)
 {
 	QUrl url(dl.url());
 
 	if (_errorDownloads.contains(url))
 		return false;
+	if (_currentDownloads.contains(url))
+		return false;
 
 	QNetworkRequest request(url);
-	request.setAttribute(QNetworkRequest::User, QVariant(dl.file()));
+	request.setAttribute(ATTR_FILE, QVariant(dl.file()));
+	if (!origin.isEmpty())
+		request.setAttribute(ATTR_ORIGIN, QVariant(origin));
 	request.setRawHeader("User-Agent", USER_AGENT);
 	QNetworkReply *reply = _manager.get(request);
 
-	_currentDownloads.append(reply);
+	_currentDownloads.insert(url, reply);
 
 	return true;
 }
@@ -58,26 +65,36 @@ bool Downloader::saveToDisk(const QString &filename, QIODevice *data)
 
 void Downloader::downloadFinished(QNetworkReply *reply)
 {
-	QUrl url = reply->url();
+	QUrl url = reply->request().url();
+
 	if (reply->error()) {
-		_errorDownloads.insert(url);
-		fprintf(stderr, "Error downloading map tile: %s: %s\n",
-		  url.toEncoded().constData(), qPrintable(reply->errorString()));
+		QUrl origin = reply->request().attribute(ATTR_ORIGIN).toUrl();
+		if (origin.isEmpty()) {
+			_errorDownloads.insert(url);
+			fprintf(stderr, "Error downloading map tile: %s: %s\n",
+			  url.toEncoded().constData(), qPrintable(reply->errorString()));
+		} else {
+			_errorDownloads.insert(origin);
+			fprintf(stderr, "Error downloading map tile: %s -> %s: %s\n",
+			  origin.toEncoded().constData(), url.toEncoded().constData(),
+			  qPrintable(reply->errorString()));
+		}
 	} else {
 		QUrl redirect = reply->attribute(
 		  QNetworkRequest::RedirectionTargetAttribute).toUrl();
-		QString filename = reply->request().attribute(QNetworkRequest::User)
+		QString filename = reply->request().attribute(ATTR_FILE)
 		  .toString();
 
 		if (!redirect.isEmpty()) {
+			QUrl origin = reply->request().attribute(ATTR_ORIGIN).toUrl();
 			Download dl(redirect, filename);
-			doDownload(dl);
+			doDownload(dl, origin.isEmpty() ? url : origin);
 		} else
 			if (!saveToDisk(filename, reply))
 				_errorDownloads.insert(url);
 	}
 
-	_currentDownloads.removeAll(reply);
+	_currentDownloads.remove(url);
 	reply->deleteLater();
 
 	if (_currentDownloads.isEmpty())
diff --git a/src/downloader.h b/src/downloader.h
index ee16262c..90badba3 100644
--- a/src/downloader.h
+++ b/src/downloader.h
@@ -5,7 +5,7 @@
 #include <QNetworkRequest>
 #include <QNetworkReply>
 #include <QUrl>
-#include <QList>
+#include <QMap>
 #include <QSet>
 
 
@@ -43,11 +43,11 @@ private:
 	Downloader(Downloader const&);
 	void operator=(Downloader const&);
 
-	bool doDownload(const Download &dl);
+	bool doDownload(const Download &dl, const QUrl &origin = QUrl());
 	bool saveToDisk(const QString &filename, QIODevice *data);
 
 	QNetworkAccessManager _manager;
-	QList<QNetworkReply *> _currentDownloads;
+	QMap<QUrl, QNetworkReply *> _currentDownloads;
 	QSet<QUrl> _errorDownloads;
 };