3 files changed, 83 insertions, 59 deletions

diff --git a/logic/net/CacheDownload.cpp b/logic/net/CacheDownload.cpp
index 6eadae39..d2a9bdee 100644
--- a/logic/net/CacheDownload.cpp
+++ b/logic/net/CacheDownload.cpp
@@ -33,25 +33,44 @@ CacheDownload::CacheDownload(QUrl url, MetaEntryPtr entry)
 
 void CacheDownload::start()
 {
+	m_status = Job_InProgress;
 	if (!m_entry->stale)
 	{
+		m_status = Job_Finished;
 		emit succeeded(m_index_within_job);
 		return;
 	}
-	m_output_file.setFileName(m_target_path);
+	// create a new save file
+	m_output_file.reset(new QSaveFile(m_target_path));
+
 	// if there already is a file and md5 checking is in effect and it can be opened
 	if (!ensureFilePathExists(m_target_path))
 	{
+		QLOG_ERROR() << "Could not create folder for " + m_target_path;
+		m_status = Job_Failed;
+		emit failed(m_index_within_job);
+		return;
+	}
+	if (!m_output_file->open(QIODevice::WriteOnly))
+	{
+		QLOG_ERROR() << "Could not open " + m_target_path + " for writing";
+		m_status = Job_Failed;
 		emit failed(m_index_within_job);
 		return;
 	}
 	QLOG_INFO() << "Downloading " << m_url.toString();
 	QNetworkRequest request(m_url);
-	if (m_entry->remote_changed_timestamp.size())
-		request.setRawHeader(QString("If-Modified-Since").toLatin1(),
-							 m_entry->remote_changed_timestamp.toLatin1());
-	if (m_entry->etag.size())
-		request.setRawHeader(QString("If-None-Match").toLatin1(), m_entry->etag.toLatin1());
+
+	// check file consistency first.
+	QFile current(m_target_path);
+	if(current.exists() && current.size() != 0)
+	{
+		if (m_entry->remote_changed_timestamp.size())
+			request.setRawHeader(QString("If-Modified-Since").toLatin1(),
+								m_entry->remote_changed_timestamp.toLatin1());
+		if (m_entry->etag.size())
+			request.setRawHeader(QString("If-None-Match").toLatin1(), m_entry->etag.toLatin1());
+	}
 
 	request.setHeader(QNetworkRequest::UserAgentHeader, "MultiMC/5.0 (Cached)");
 
@@ -77,76 +96,74 @@ void CacheDownload::downloadProgress(qint64 bytesReceived, qint64 bytesTotal)
 void CacheDownload::downloadError(QNetworkReply::NetworkError error)
 {
 	// error happened during download.
-	QLOG_ERROR() << "Failed" << m_url.toString() << "with reason" << error;
+	QLOG_ERROR() << "Failed " << m_url.toString() << " with reason " << error;
 	m_status = Job_Failed;
 }
 void CacheDownload::downloadFinished()
 {
 	// if the download succeeded
-	if (m_status != Job_Failed)
+	if (m_status == Job_Failed)
 	{
+		m_output_file->cancelWriting();
+		m_reply.reset();
+		emit failed(m_index_within_job);
+		return;
+	}
 
+	// if we wrote any data to the save file, we try to commit the data to the real file.
+	if (wroteAnyData)
+	{
 		// nothing went wrong...
-		m_status = Job_Finished;
-		if (m_output_file.isOpen())
+		if (m_output_file->commit())
 		{
-			// save the data to the downloadable if we aren't saving to file
-			m_output_file.close();
+			m_status = Job_Finished;
 			m_entry->md5sum = md5sum.result().toHex().constData();
 		}
 		else
 		{
-			if (m_output_file.open(QIODevice::ReadOnly))
-			{
-				m_entry->md5sum =
-					QCryptographicHash::hash(m_output_file.readAll(), QCryptographicHash::Md5)
-						.toHex()
-						.constData();
-				m_output_file.close();
-			}
-		}
-		QFileInfo output_file_info(m_target_path);
-
-		m_entry->etag = m_reply->rawHeader("ETag").constData();
-		if (m_reply->hasRawHeader("Last-Modified"))
-		{
-			m_entry->remote_changed_timestamp = m_reply->rawHeader("Last-Modified").constData();
+			QLOG_ERROR() << "Failed to commit changes to " << m_target_path;
+			m_output_file->cancelWriting();
+			m_reply.reset();
+			m_status = Job_Failed;
+			emit failed(m_index_within_job);
+			return;
 		}
-		m_entry->local_changed_timestamp =
-			output_file_info.lastModified().toUTC().toMSecsSinceEpoch();
-		m_entry->stale = false;
-		MMC->metacache()->updateEntry(m_entry);
-
-		m_reply.reset();
-		emit succeeded(m_index_within_job);
-		return;
 	}
-	// else the download failed
 	else
 	{
-		m_output_file.close();
-		m_output_file.remove();
-		m_reply.reset();
-		emit failed(m_index_within_job);
-		return;
+		m_status = Job_Finished;
+	}
+
+	// then get rid of the save file
+	m_output_file.reset();
+
+	QFileInfo output_file_info(m_target_path);
+
+	m_entry->etag = m_reply->rawHeader("ETag").constData();
+	if (m_reply->hasRawHeader("Last-Modified"))
+	{
+		m_entry->remote_changed_timestamp = m_reply->rawHeader("Last-Modified").constData();
 	}
+	m_entry->local_changed_timestamp =
+		output_file_info.lastModified().toUTC().toMSecsSinceEpoch();
+	m_entry->stale = false;
+	MMC->metacache()->updateEntry(m_entry);
+
+	m_reply.reset();
+	emit succeeded(m_index_within_job);
+	return;
 }
 
 void CacheDownload::downloadReadyRead()
 {
-	if (!m_output_file.isOpen())
-	{
-		if (!m_output_file.open(QIODevice::WriteOnly))
-		{
-			/*
-			* Can't open the file... the job failed
-			*/
-			m_reply->abort();
-			emit failed(m_index_within_job);
-			return;
-		}
-	}
 	QByteArray ba = m_reply->readAll();
 	md5sum.addData(ba);
-	m_output_file.write(ba);
+	if (m_output_file->write(ba) != ba.size())
+	{
+		QLOG_ERROR() << "Failed writing into " + m_target_path;
+		m_status = Job_Failed;
+		m_reply->abort();
+		emit failed(m_index_within_job);
+	}
+	wroteAnyData = true;
 }
diff --git a/logic/net/CacheDownload.h b/logic/net/CacheDownload.h
index e25aecd2..154f5988 100644
--- a/logic/net/CacheDownload.h
+++ b/logic/net/CacheDownload.h
@@ -17,29 +17,34 @@
 
 #include "NetAction.h"
 #include "HttpMetaCache.h"
-#include <QFile>
-#include <qcryptographichash.h>
+#include <QCryptographicHash>
+#include <QSaveFile>
 
 typedef std::shared_ptr<class CacheDownload> CacheDownloadPtr;
 class CacheDownload : public NetAction
 {
 	Q_OBJECT
-public:
+private:
 	MetaEntryPtr m_entry;
 	/// if saving to file, use the one specified in this string
 	QString m_target_path;
 	/// this is the output file, if any
-	QFile m_output_file;
+	std::shared_ptr<QSaveFile> m_output_file;
 	/// the hash-as-you-download
 	QCryptographicHash md5sum;
 
+	bool wroteAnyData = false;
+
 public:
 	explicit CacheDownload(QUrl url, MetaEntryPtr entry);
 	static CacheDownloadPtr make(QUrl url, MetaEntryPtr entry)
 	{
 		return CacheDownloadPtr(new CacheDownload(url, entry));
 	}
-
+	QString getTargetFilepath()
+	{
+		return m_target_path;
+	}
 protected
 slots:
 	virtual void downloadProgress(qint64 bytesReceived, qint64 bytesTotal);
diff --git a/logic/net/URLConstants.h b/logic/net/URLConstants.h
index 9579198d..8cb1f3fd 100644
--- a/logic/net/URLConstants.h
+++ b/logic/net/URLConstants.h
@@ -31,4 +31,6 @@ const QString SKINS_BASE("skins.minecraft.net/MinecraftSkins/");
 const QString AUTH_BASE("authserver.mojang.com/");
 const QString FORGE_LEGACY_URL("http://files.minecraftforge.net/minecraftforge/json");
 const QString FORGE_GRADLE_URL("http://files.minecraftforge.net/maven/net/minecraftforge/forge/json");
+const QString MOJANG_STATUS_URL("http://status.mojang.com/check");
+const QString MOJANG_STATUS_NEWS_URL("http://status.mojang.com/news");
 }