Simplify URLRequestCustomJob handling

Improve implementation of URLRequestCustomJob:

* remove qmutex, pass values using PostTask
* do not use base::WeakPtr which is not thread safe and must
  always be dereferenced on the same thread
* add proxy object to handle interactions between threads
* do not use QPointer to track IODevice since it does not solve
  anything for us
* QIODevice in reply method is used only by IO thread
* do not make shared object to commit suicide,
  instead use refcounted object
* improve documentation about thread safety issue of QIODevice
  object in reply method

Change-Id: Ic29bf262de8082dfd46cb9217a68f3c982d16b9e
Reviewed-by: Leena Miettinen <riitta-leena.miettinen@qt.io>
Reviewed-by: Allan Sandfeld Jensen <allan.jensen@qt.io>

1 files changed, 7 insertions, 1 deletions

diff --git a/src/core/api/qwebengineurlrequestjob.cpp b/src/core/api/qwebengineurlrequestjob.cpp
index 742bdf527..a071adbd5 100644
--- a/src/core/api/qwebengineurlrequestjob.cpp
+++ b/src/core/api/qwebengineurlrequestjob.cpp
@@ -115,10 +115,16 @@ QByteArray QWebEngineUrlRequestJob::requestMethod() const
 
 /*!
     Replies to the request with \a device and the MIME type \a contentType.
+    The user has to be aware that \a device will be used on another thread
+    until the job is deleted. In case simultaneous access from the main thread
+    is desired, the user is reponsible for making access to \a device thread-safe
+    for example by using QMutex. Note that the \a device object is not owned by
+    the web engine. Therefore, the signal QObject::destroyed() of
+    QWebEngineUrlRequestJob must be monitored.
  */
 void QWebEngineUrlRequestJob::reply(const QByteArray &contentType, QIODevice *device)
 {
-    d_ptr->setReply(contentType, device);
+    d_ptr->reply(contentType, device);
 }
 
 /*!