NOISSUE refactor *Download into more, smaller pieces

* Download is now Download.
* Download uses Sink subclasses to process various events.
* Validators can be used to further customize the Sink behaviour.

1 files changed, 199 insertions, 0 deletions

diff --git a/api/logic/net/Download.cpp b/api/logic/net/Download.cpp
new file mode 100644
index 00000000..70fe7608
--- /dev/null
+++ b/api/logic/net/Download.cpp
@@ -0,0 +1,199 @@
+/* Copyright 2013-2015 MultiMC Contributors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "Download.h"
+
+#include <QFileInfo>
+#include <QDateTime>
+#include <QDebug>
+#include "Env.h"
+#include <FileSystem.h>
+#include "ChecksumValidator.h"
+#include "MetaCacheSink.h"
+#include "ByteArraySink.h"
+
+namespace Net {
+
+Download::Download():NetAction()
+{
+	m_status = Job_NotStarted;
+}
+
+Download::Ptr Download::makeCached(QUrl url, MetaEntryPtr entry)
+{
+	Download * dl = new Download();
+	dl->m_url = url;
+	auto md5Node = new ChecksumValidator(QCryptographicHash::Md5);
+	auto cachedNode = new MetaCacheSink(entry, md5Node);
+	dl->m_sink.reset(cachedNode);
+	dl->m_target_path = entry->getFullPath();
+	return std::shared_ptr<Download>(dl);
+}
+
+Download::Ptr Download::makeByteArray(QUrl url, QByteArray *output)
+{
+	Download * dl = new Download();
+	dl->m_url = url;
+	dl->m_sink.reset(new ByteArraySink(output));
+	return std::shared_ptr<Download>(dl);
+}
+
+Download::Ptr Download::makeFile(QUrl url, QString path)
+{
+	Download * dl = new Download();
+	dl->m_url = url;
+	dl->m_sink.reset(new FileSink(path));
+	return std::shared_ptr<Download>(dl);
+}
+
+void Download::addValidator(Validator * v)
+{
+	m_sink->addValidator(v);
+}
+
+void Download::start()
+{
+	QNetworkRequest request(m_url);
+	m_status = m_sink->init(request);
+	switch(m_status)
+	{
+		case Job_Finished:
+			emit succeeded(m_index_within_job);
+			qDebug() << "Download cache hit " << m_url.toString();
+			return;
+		case Job_InProgress:
+			qDebug() << "Downloading " << m_url.toString();
+			break;
+		case Job_NotStarted:
+		case Job_Failed:
+			emit failed(m_index_within_job);
+			return;
+	}
+
+	request.setHeader(QNetworkRequest::UserAgentHeader, "MultiMC/5.0");
+
+	auto worker = ENV.qnam();
+	QNetworkReply *rep = worker->get(request);
+
+	m_reply.reset(rep);
+	connect(rep, SIGNAL(downloadProgress(qint64, qint64)), SLOT(downloadProgress(qint64, qint64)));
+	connect(rep, SIGNAL(finished()), SLOT(downloadFinished()));
+	connect(rep, SIGNAL(error(QNetworkReply::NetworkError)), SLOT(downloadError(QNetworkReply::NetworkError)));
+	connect(rep, SIGNAL(readyRead()), SLOT(downloadReadyRead()));
+}
+
+void Download::downloadProgress(qint64 bytesReceived, qint64 bytesTotal)
+{
+	m_total_progress = bytesTotal;
+	m_progress = bytesReceived;
+	emit netActionProgress(m_index_within_job, bytesReceived, bytesTotal);
+}
+
+void Download::downloadError(QNetworkReply::NetworkError error)
+{
+	// error happened during download.
+	qCritical() << "Failed " << m_url.toString() << " with reason " << error;
+	m_status = Job_Failed;
+}
+
+bool Download::handleRedirect()
+{
+	QVariant redirect = m_reply->header(QNetworkRequest::LocationHeader);
+	QString redirectURL;
+	if(redirect.isValid())
+	{
+		redirectURL = redirect.toString();
+	}
+	// FIXME: This is a hack for https://bugreports.qt-project.org/browse/QTBUG-41061
+	else if(m_reply->hasRawHeader("Location"))
+	{
+		auto data = m_reply->rawHeader("Location");
+		if(data.size() > 2 && data[0] == '/' && data[1] == '/')
+		{
+			redirectURL = m_reply->url().scheme() + ":" + data;
+		}
+	}
+	if (!redirectURL.isEmpty())
+	{
+		m_url = QUrl(redirect.toString());
+		qDebug() << "Following redirect to " << m_url.toString();
+		start();
+		return true;
+	}
+	return false;
+}
+
+
+void Download::downloadFinished()
+{
+	// handle HTTP redirection first
+	if(handleRedirect())
+	{
+		qDebug() << "Download redirected:" << m_url.toString();
+		return;
+	}
+
+	// if the download failed before this point ...
+	if (m_status == Job_Failed)
+	{
+		qDebug() << "Download failed in previous step:" << m_url.toString();
+		m_sink->abort();
+		m_reply.reset();
+		emit failed(m_index_within_job);
+		return;
+	}
+
+	// make sure we got all the remaining data, if any
+	auto data = m_reply->readAll();
+	if(data.size())
+	{
+		qDebug() << "Writing extra" << data.size() << "bytes to" << m_target_path;
+		m_status = m_sink->write(data);
+	}
+
+	// otherwise, finalize the whole graph
+	m_status = m_sink->finalize(*m_reply.get());
+	if (m_status != Job_Finished)
+	{
+		qDebug() << "Download failed to finalize:" << m_url.toString();
+		m_sink->abort();
+		m_reply.reset();
+		emit failed(m_index_within_job);
+		return;
+	}
+	m_reply.reset();
+	qDebug() << "Download succeeded:" << m_url.toString();
+	emit succeeded(m_index_within_job);
+}
+
+void Download::downloadReadyRead()
+{
+	if(m_status == Job_InProgress)
+	{
+		auto data = m_reply->readAll();
+		m_status = m_sink->write(data);
+		if(m_status == Job_Failed)
+		{
+			qCritical() << "Failed to process response chunk for " << m_target_path;
+		}
+		// qDebug() << "Download" << m_url.toString() << "gained" << data.size() << "bytes";
+	}
+	else
+	{
+		qCritical() << "Cannot write to " << m_target_path << ", illegal status" << m_status;
+	}
+}
+
+}