Async open file support in QNetworkAccessManager

This change adds support for BackgroundRequestAttribute to local file request. It is useful
when opening files located in network drives where the file open operation could take several
seconds to complete. When this attribute is activated the QNetworkAccessManager::get call
returns the reply immediately and the user has to wait until QNetworkReply::finished signal
is emitted or QNetworkReply::isFinished function returns true.

Task-number: QTBUG-45925
Change-Id: Ie2019dd94fe04253d1ef6874811d7e749a5aad93
Reviewed-by: Edward Welbourne <edward.welbourne@theqtcompany.com>
Reviewed-by: Timur Pocheptsov <timur.pocheptsov@theqtcompany.com>

1 files changed, 96 insertions, 54 deletions

diff --git a/src/network/access/qnetworkreplyfileimpl.cpp b/src/network/access/qnetworkreplyfileimpl.cpp
index bd89659689..8d63fa3fd6 100644
--- a/src/network/access/qnetworkreplyfileimpl.cpp
+++ b/src/network/access/qnetworkreplyfileimpl.cpp
@@ -40,31 +40,45 @@
 #include "qnetworkreplyfileimpl_p.h"
 
 #include "QtCore/qdatetime.h"
+#include "qnetworkaccessmanager_p.h"
 #include <QtCore/QCoreApplication>
 #include <QtCore/QFileInfo>
+#include <QtCore/QThread>
+#include "qnetworkfile_p.h"
+#include "qnetworkrequest.h"
 
 QT_BEGIN_NAMESPACE
 
 QNetworkReplyFileImplPrivate::QNetworkReplyFileImplPrivate()
-    : QNetworkReplyPrivate(), realFileSize(0)
+    : QNetworkReplyPrivate(), managerPrivate(0), realFile(0)
 {
+    qRegisterMetaType<QNetworkRequest::KnownHeaders>();
+    qRegisterMetaType<QNetworkReply::NetworkError>();
 }
 
 QNetworkReplyFileImpl::~QNetworkReplyFileImpl()
 {
+    QNetworkReplyFileImplPrivate *d = (QNetworkReplyFileImplPrivate*) d_func();
+    if (d->realFile) {
+        if (d->realFile->thread() == QThread::currentThread())
+            delete d->realFile;
+        else
+            QMetaObject::invokeMethod(d->realFile, "deleteLater", Qt::QueuedConnection);
+    }
 }
 
-QNetworkReplyFileImpl::QNetworkReplyFileImpl(QObject *parent, const QNetworkRequest &req, const QNetworkAccessManager::Operation op)
-    : QNetworkReply(*new QNetworkReplyFileImplPrivate(), parent)
+QNetworkReplyFileImpl::QNetworkReplyFileImpl(QNetworkAccessManager *manager, const QNetworkRequest &req, const QNetworkAccessManager::Operation op)
+    : QNetworkReply(*new QNetworkReplyFileImplPrivate(), manager)
 {
     setRequest(req);
     setUrl(req.url());
     setOperation(op);
-    setFinished(true);
     QNetworkReply::open(QIODevice::ReadOnly);
 
     QNetworkReplyFileImplPrivate *d = (QNetworkReplyFileImplPrivate*) d_func();
 
+    d->managerPrivate = manager->d_func();
+
     QUrl url = req.url();
     if (url.host() == QLatin1String("localhost"))
         url.setHost(QString());
@@ -77,7 +91,7 @@ QNetworkReplyFileImpl::QNetworkReplyFileImpl(QObject *parent, const QNetworkRequ
         setError(QNetworkReply::ProtocolInvalidOperationError, msg);
         QMetaObject::invokeMethod(this, "error", Qt::QueuedConnection,
             Q_ARG(QNetworkReply::NetworkError, QNetworkReply::ProtocolInvalidOperationError));
-        QMetaObject::invokeMethod(this, "finished", Qt::QueuedConnection);
+        fileOpenFinished(false);
         return;
     }
 #endif
@@ -85,7 +99,6 @@ QNetworkReplyFileImpl::QNetworkReplyFileImpl(QObject *parent, const QNetworkRequ
         url.setPath(QLatin1String("/"));
     setUrl(url);
 
-
     QString fileName = url.toLocalFile();
     if (fileName.isEmpty()) {
         if (url.scheme() == QLatin1String("qrc")) {
@@ -100,68 +113,85 @@ QNetworkReplyFileImpl::QNetworkReplyFileImpl(QObject *parent, const QNetworkRequ
         }
     }
 
-    QFileInfo fi(fileName);
-    if (fi.isDir()) {
-        QString msg = QCoreApplication::translate("QNetworkAccessFileBackend", "Cannot open %1: Path is a directory").arg(url.toString());
-        setError(QNetworkReply::ContentOperationNotPermittedError, msg);
-        QMetaObject::invokeMethod(this, "error", Qt::QueuedConnection,
-            Q_ARG(QNetworkReply::NetworkError, QNetworkReply::ContentOperationNotPermittedError));
-        QMetaObject::invokeMethod(this, "finished", Qt::QueuedConnection);
-        return;
-    }
-
-    d->realFile.setFileName(fileName);
-    bool opened = d->realFile.open(QIODevice::ReadOnly | QIODevice::Unbuffered);
-
-    // could we open the file?
-    if (!opened) {
-        QString msg = QCoreApplication::translate("QNetworkAccessFileBackend", "Error opening %1: %2")
-                .arg(d->realFile.fileName(), d->realFile.errorString());
-
-        if (d->realFile.exists()) {
-            setError(QNetworkReply::ContentAccessDenied, msg);
-            QMetaObject::invokeMethod(this, "error", Qt::QueuedConnection,
-                Q_ARG(QNetworkReply::NetworkError, QNetworkReply::ContentAccessDenied));
-        } else {
-            setError(QNetworkReply::ContentNotFoundError, msg);
+    if (req.attribute(QNetworkRequest::BackgroundRequestAttribute).toBool()) { // Asynchronous open
+        auto realFile = new QNetworkFile(fileName);
+        connect(realFile, &QNetworkFile::headerRead, this, &QNetworkReplyFileImpl::setHeader,
+                Qt::QueuedConnection);
+        connect(realFile, &QNetworkFile::error, this, &QNetworkReplyFileImpl::setError,
+                Qt::QueuedConnection);
+        connect(realFile, SIGNAL(finished(bool)), SLOT(fileOpenFinished(bool)),
+                Qt::QueuedConnection);
+
+        realFile->moveToThread(d->managerPrivate->createThread());
+        QMetaObject::invokeMethod(realFile, "open", Qt::QueuedConnection);
+
+        d->realFile = realFile;
+    } else { // Synch open
+        setFinished(true);
+
+        QFileInfo fi(fileName);
+        if (fi.isDir()) {
+            QString msg = QCoreApplication::translate("QNetworkAccessFileBackend", "Cannot open %1: Path is a directory").arg(url.toString());
+            setError(QNetworkReply::ContentOperationNotPermittedError, msg);
             QMetaObject::invokeMethod(this, "error", Qt::QueuedConnection,
-                Q_ARG(QNetworkReply::NetworkError, QNetworkReply::ContentNotFoundError));
+                Q_ARG(QNetworkReply::NetworkError, QNetworkReply::ContentOperationNotPermittedError));
+            QMetaObject::invokeMethod(this, "finished", Qt::QueuedConnection);
+            return;
+        }
+        d->realFile = new QFile(fileName, this);
+        bool opened = d->realFile->open(QIODevice::ReadOnly | QIODevice::Unbuffered);
+
+        // could we open the file?
+        if (!opened) {
+            QString msg = QCoreApplication::translate("QNetworkAccessFileBackend", "Error opening %1: %2")
+                    .arg(d->realFile->fileName(), d->realFile->errorString());
+
+            if (fi.exists()) {
+                setError(QNetworkReply::ContentAccessDenied, msg);
+                QMetaObject::invokeMethod(this, "error", Qt::QueuedConnection,
+                    Q_ARG(QNetworkReply::NetworkError, QNetworkReply::ContentAccessDenied));
+            } else {
+                setError(QNetworkReply::ContentNotFoundError, msg);
+                QMetaObject::invokeMethod(this, "error", Qt::QueuedConnection,
+                    Q_ARG(QNetworkReply::NetworkError, QNetworkReply::ContentNotFoundError));
+            }
+            QMetaObject::invokeMethod(this, "finished", Qt::QueuedConnection);
+            return;
         }
+        setHeader(QNetworkRequest::LastModifiedHeader, fi.lastModified());
+        setHeader(QNetworkRequest::ContentLengthHeader, fi.size());
+
+        QMetaObject::invokeMethod(this, "metaDataChanged", Qt::QueuedConnection);
+        QMetaObject::invokeMethod(this, "downloadProgress", Qt::QueuedConnection,
+            Q_ARG(qint64, fi.size()), Q_ARG(qint64, fi.size()));
+        QMetaObject::invokeMethod(this, "readyRead", Qt::QueuedConnection);
         QMetaObject::invokeMethod(this, "finished", Qt::QueuedConnection);
-        return;
     }
-
-    setHeader(QNetworkRequest::LastModifiedHeader, fi.lastModified());
-    d->realFileSize = fi.size();
-    setHeader(QNetworkRequest::ContentLengthHeader, d->realFileSize);
-
-    QMetaObject::invokeMethod(this, "metaDataChanged", Qt::QueuedConnection);
-    QMetaObject::invokeMethod(this, "downloadProgress", Qt::QueuedConnection,
-        Q_ARG(qint64, d->realFileSize), Q_ARG(qint64, d->realFileSize));
-    QMetaObject::invokeMethod(this, "readyRead", Qt::QueuedConnection);
-    QMetaObject::invokeMethod(this, "finished", Qt::QueuedConnection);
 }
 
 void QNetworkReplyFileImpl::close()
 {
     Q_D(QNetworkReplyFileImpl);
     QNetworkReply::close();
-    d->realFile.close();
+    if (d->realFile) {
+        if (d->realFile->thread() == thread())
+            d->realFile->close();
+        else
+            QMetaObject::invokeMethod(d->realFile, "close", Qt::QueuedConnection);
+    }
 }
 
 void QNetworkReplyFileImpl::abort()
 {
-    Q_D(QNetworkReplyFileImpl);
-    QNetworkReply::close();
-    d->realFile.close();
+    close();
 }
 
 qint64 QNetworkReplyFileImpl::bytesAvailable() const
 {
     Q_D(const QNetworkReplyFileImpl);
-    if (!d->realFile.isOpen())
+    if (!d->isFinished || !d->realFile || !d->realFile->isOpen())
         return QNetworkReply::bytesAvailable();
-    return QNetworkReply::bytesAvailable() + d->realFile.bytesAvailable();
+    return QNetworkReply::bytesAvailable() + d->realFile->bytesAvailable();
 }
 
 bool QNetworkReplyFileImpl::isSequential () const
@@ -171,8 +201,9 @@ bool QNetworkReplyFileImpl::isSequential () const
 
 qint64 QNetworkReplyFileImpl::size() const
 {
-    Q_D(const QNetworkReplyFileImpl);
-    return d->realFileSize;
+    bool ok;
+    int size = header(QNetworkRequest::ContentLengthHeader).toInt(&ok);
+    return ok ? size : 0;
 }
 
 /*!
@@ -181,11 +212,11 @@ qint64 QNetworkReplyFileImpl::size() const
 qint64 QNetworkReplyFileImpl::readData(char *data, qint64 maxlen)
 {
     Q_D(QNetworkReplyFileImpl);
-    if (!d->realFile.isOpen())
+    if (!d->isFinished || !d->realFile || !d->realFile->isOpen())
         return -1;
-    qint64 ret = d->realFile.read(data, maxlen);
-    if (bytesAvailable() == 0 && d->realFile.isOpen())
-        d->realFile.close();
+    qint64 ret = d->realFile->read(data, maxlen);
+    if (bytesAvailable() == 0)
+        d->realFile->close();
     if (ret == 0 && bytesAvailable() == 0)
         return -1;
     else {
@@ -195,6 +226,17 @@ qint64 QNetworkReplyFileImpl::readData(char *data, qint64 maxlen)
     }
 }
 
+void QNetworkReplyFileImpl::fileOpenFinished(bool isOpen)
+{
+    setFinished(true);
+    if (isOpen) {
+        const auto fileSize = size();
+        Q_EMIT metaDataChanged();
+        Q_EMIT downloadProgress(fileSize, fileSize);
+        Q_EMIT readyRead();
+    }
+    Q_EMIT finished();
+}
 
 QT_END_NAMESPACE