////  SendAssetTask.cpp//  assignment-client/src/assets////  Created by Ryan Huffman on 2015/08/26//  Copyright 2015 High Fidelity, Inc.////  Distributed under the Apache License, Version 2.0.//  See the accompanying file LICENSE or http://www.apache.org/licenses/LICENSE-2.0.html// #include "SendAssetTask.h" #include <cmath> #include <QFile> #include <DependencyManager.h>#include <NetworkLogging.h>#include <NLPacket.h>#include <NLPacketList.h>#include <NodeList.h>#include <udt/Packet.h> #include "AssetUtils.h"#include "ByteRange.h"#include "ClientServerUtils.h" SendAssetTask::SendAssetTask(QSharedPointer<ReceivedMessage> message, const SharedNodePointer& sendToNode, const QDir& resourcesDir) :    QRunnable(),    _message(message),    _senderNode(sendToNode),    _resourcesDir(resourcesDir){    } void SendAssetTask::run() {    MessageID messageID;    ByteRange byteRange;     _message->readPrimitive(&messageID);    QByteArray assetHash = _message->read(AssetUtils::SHA256_HASH_LENGTH);     // `start` and `end` indicate the range of data to retrieve for the asset identified by `assetHash`.    // `start` is inclusive, `end` is exclusive. Requesting `start` = 1, `end` = 10 will retrieve 9 bytes of data,    // starting at index 1.    _message->readPrimitive(&byteRange.fromInclusive);    _message->readPrimitive(&byteRange.toExclusive);        QString hexHash = assetHash.toHex();        qDebug() << "Received a request for the file (" << messageID << "): " << hexHash << " from "        << byteRange.fromInclusive << " to " << byteRange.toExclusive;        qDebug() << "Starting task to send asset: " << hexHash << " for messageID " << messageID;    auto replyPacketList = NLPacketList::create(PacketType::AssetGetReply, QByteArray(), true, true);     replyPacketList->write(assetHash);     replyPacketList->writePrimitive(messageID);     if (!byteRange.isValid()) {        replyPacketList->writePrimitive(AssetUtils::AssetServerError::InvalidByteRange);    } else {        QString filePath = _resourcesDir.filePath(QString(hexHash));                QFile file { filePath };         if (file.open(QIODevice::ReadOnly)) {             // first fixup the range based on the now known file size            byteRange.fixupRange(file.size());             // check if we're being asked to read data that we just don't have            // because of the file size            if (file.size() < byteRange.fromInclusive || file.size() < byteRange.toExclusive) {                replyPacketList->writePrimitive(AssetUtils::AssetServerError::InvalidByteRange);                qCDebug(networking) << "Bad byte range: " << hexHash << " "                    << byteRange.fromInclusive << ":" << byteRange.toExclusive;            } else {                // we have a valid byte range, handle it and send the asset                auto size = byteRange.size();                 if (byteRange.fromInclusive >= 0) {                     // this range is positive, meaning we just need to seek into the file and then read from there                    file.seek(byteRange.fromInclusive);                    replyPacketList->writePrimitive(AssetUtils::AssetServerError::NoError);                    replyPacketList->writePrimitive(size);                    replyPacketList->write(file.read(size));                } else {                    // this range is negative, at least the first part of the read will be back into the end of the file                     // seek to the part of the file where the negative range begins                    file.seek(file.size() + byteRange.fromInclusive);                     replyPacketList->writePrimitive(AssetUtils::AssetServerError::NoError);                    replyPacketList->writePrimitive(size);                     // first write everything from the negative range to the end of the file                    replyPacketList->write(file.read(size));                }                 qCDebug(networking) << "Sending asset: " << hexHash;            }            file.close();        } else {            qCDebug(networking) << "Asset not found: " << filePath << "(" << hexHash << ")";            replyPacketList->writePrimitive(AssetUtils::AssetServerError::AssetNotFound);        }    }     auto nodeList = DependencyManager::get<NodeList>();    if (_senderNode) {        nodeList->sendPacketList(std::move(replyPacketList), *_senderNode);    } else {        nodeList->sendPacketList(std::move(replyPacketList), _message->getSenderSockAddr());    }}