2 files changed, 140 insertions, 0 deletions
diff --git a/jobs/downloadfilejob.cpp b/jobs/downloadfilejob.cpp
new file mode 100644
index 00000000..2530e259
--- /dev/null
+++ b/jobs/downloadfilejob.cpp
@@ -0,0 +1,113 @@
+#include "downloadfilejob.h"
+
+#include <QtNetwork/QNetworkReply>
+#include <QtCore/QFile>
+#include <QtCore/QTemporaryFile>
+
+using namespace QMatrixClient;
+
+class DownloadFileJob::Private
+{
+    public:
+        Private() : tempFile(new QTemporaryFile()) { }
+
+        explicit Private(const QString& localFilename)
+            : targetFile(new QFile(localFilename))
+            , tempFile(new QFile(targetFile->fileName() + ".qmcdownload"))
+        { }
+
+        QScopedPointer<QFile> targetFile;
+        QScopedPointer<QFile> tempFile;
+};
+
+DownloadFileJob::DownloadFileJob(const QString& serverName,
+                                 const QString& mediaId,
+                                 const QString& localFilename)
+    : GetContentJob(serverName, mediaId)
+    , d(localFilename.isEmpty() ? new Private : new Private(localFilename))
+{
+    setObjectName("DownloadFileJob");
+}
+
+QString DownloadFileJob::targetFileName() const
+{
+    return (d->targetFile ? d->targetFile : d->tempFile)->fileName();
+}
+
+void DownloadFileJob::beforeStart(const ConnectionData*)
+{
+    if (d->targetFile && !d->targetFile->open(QIODevice::WriteOnly))
+    {
+        qCWarning(JOBS) << "Couldn't open the file"
+                        << d->targetFile->fileName() << "for writing";
+        setStatus(FileError, "Could not open the target file for writing");
+        return;
+    }
+    if (!d->tempFile->open(QIODevice::WriteOnly))
+    {
+        qCWarning(JOBS) << "Couldn't open the temporary file"
+                        << d->tempFile->fileName() << "for writing";
+        setStatus(FileError, "Could not open the temporary download file");
+    }
+    qCDebug(JOBS) << "Downloading to" << d->tempFile->fileName();
+}
+
+void DownloadFileJob::afterStart(const ConnectionData*, QNetworkReply* reply)
+{
+    connect(reply, &QNetworkReply::metaDataChanged, this, [this,reply] {
+        auto sizeHeader = reply->header(QNetworkRequest::ContentLengthHeader);
+        if (sizeHeader.isValid())
+        {
+            auto targetSize = sizeHeader.value<qint64>();
+            if (targetSize != -1)
+                if (!d->tempFile->resize(targetSize))
+                {
+                    qCWarning(JOBS) << "Failed to allocate" << targetSize
+                                    << "bytes for" << d->tempFile->fileName();
+                    setStatus(FileError,
+                              "Could not reserve disk space for download");
+                }
+        }
+    });
+    connect(reply, &QIODevice::readyRead, this, [this,reply] {
+            auto bytes = reply->read(reply->bytesAvailable());
+            if (bytes.isEmpty())
+            {
+                qCWarning(JOBS)
+                        << "Unexpected empty chunk when downloading from"
+                        << reply->url() << "to" << d->tempFile->fileName();
+            } else {
+                d->tempFile->write(bytes);
+            }
+    });
+}
+
+void DownloadFileJob::beforeAbandon(QNetworkReply*)
+{
+    if (d->targetFile)
+        d->targetFile->remove();
+    d->tempFile->remove();
+}
+
+BaseJob::Status DownloadFileJob::parseReply(QNetworkReply*)
+{
+    if (d->targetFile)
+    {
+        d->targetFile->close();
+        if (!d->targetFile->remove())
+        {
+            qCWarning(JOBS) << "Failed to remove the target file placeholder";
+            return { FileError, "Couldn't finalise the download" };
+        }
+        if (!d->tempFile->rename(d->targetFile->fileName()))
+        {
+            qCWarning(JOBS) << "Failed to rename" << d->tempFile->fileName()
+                            << "to" << d->targetFile->fileName();
+            return { FileError, "Couldn't finalise the download" };
+        }
+    }
+    else
+        d->tempFile->close();
+    qCDebug(JOBS) << "Saved a file as" << targetFileName();
+    return Success;
+}
diff --git a/jobs/downloadfilejob.h b/jobs/downloadfilejob.h
new file mode 100644
index 00000000..d798506c
--- /dev/null
+++ b/jobs/downloadfilejob.h
@@ -0,0 +1,27 @@
+#pragma once
+
+#include "generated/content-repo.h"
+
+namespace QMatrixClient
+{
+    class DownloadFileJob : public GetContentJob
+    {
+        public:
+            enum { FileError = BaseJob::UserDefinedError + 1 };
+
+            DownloadFileJob(const QString& serverName, const QString& mediaId,
+                            const QString& localFilename = {});
+
+            QString targetFileName() const;
+
+        private:
+            class Private;
+            QScopedPointer<Private> d;
+
+            void beforeStart(const ConnectionData*) override;
+            void afterStart(const ConnectionData*,
+                            QNetworkReply* reply) override;
+            void beforeAbandon(QNetworkReply*) override;
+            Status parseReply(QNetworkReply*) override;
+    };
+}