QNetworkAccessBackend: emit readyRead less often

Once per iteration of the loop wouldn't theoretically be so bad if there
was no overhead to emitting signals or reading from buffers.

Change-Id: I0e424264fcc95eb2e2e5f8f908cf9ae3a7cc4b7e
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Edward Welbourne <edward.welbourne@qt.io>

1 files changed, 4 insertions, 1 deletions

diff --git a/src/network/access/qnetworkreplyimpl.cpp b/src/network/access/qnetworkreplyimpl.cpp
index 39729dd13a..035610d6d6 100644
--- a/src/network/access/qnetworkreplyimpl.cpp
+++ b/src/network/access/qnetworkreplyimpl.cpp
@@ -734,6 +734,7 @@ void QNetworkReplyImplPrivate::readFromBackend()
         if (backend->bytesAvailable())
             emit q->readyRead();
     } else {
+        bool anyBytesRead = false;
         while (backend->bytesAvailable()
                && (!readBufferMaxSize || buffer.size() < readBufferMaxSize)) {
             qint64 toRead = qMin(nextDownstreamBlockSize(), backend->bytesAvailable());
@@ -743,8 +744,10 @@ void QNetworkReplyImplPrivate::readFromBackend()
             qint64 bytesRead = backend->read(data, toRead);
             Q_ASSERT(bytesRead <= toRead);
             buffer.chop(toRead - bytesRead);
-            emit q->readyRead();
+            anyBytesRead |= bytesRead > 0;
         }
+        if (anyBytesRead)
+            emit q->readyRead();
     }
 }