Write access to the shared memory region is required because JavaScript lacks
the capability to create read-only ArrayBuffers. When a user attempts to modify
an ArrayBuffer that utilizes a ReadOnlySharedMemoryRegion as its BackingStore
it triggers an access violation.
Note that this pull request may be reverted in the future if JavaScript adds
read-only ArrayBuffer support.
Send a FrameDetached message from CefFrameHostImpl::Detach before closing
the RenderFrame connection to avoid an immediate reconnect attempt by the
renderer.
When BFCache is disabled the intentionally detached frame will never be
reconnected. When BFCache is enabled the intentionally detached frame will
be reconnected via CefFrameImpl::OnWasShown if/when it exits the cache.
CefSharedProcessMessageBuilder supports creation of a CefProcessMessage
backed by a CefSharedMemoryRegion.
Performance tests comparing the existing ArgumentList approach and the new
SharedMemoryRegion approach have been added to cefclient at
http://tests/ipc_performance.
CefMessageRouter has been updated to use SharedMemoryRegion as transport
for larger message payloads. The threshold is configurable via
|CefMessageRouterConfig.message_size_threshold|.
To test:
run `ceftests --gtest_filter=SendSharedProcessMessageTest.*:SharedProcessMessageTest.*:MessageRouterTest.Threshold*`
The mojo channel used for frame communication may disconnect for a variety of
reasons including frame navigation, frame destruction, or insertion into the
BackForwardCache (when the browser-side frame representation is destroyed and
closes the connection). When disconnect occurs we now evaluate the situation
and reconnect if appropriate.
Connections are now initiated solely from the renderer process and the
RenderFrame is passed as an argument to FrameAttached() instead of being
retrieved independently. Messages are queued while the frame is disconnected
and sent only after FrameAttachedAck() is received from the browser process.
The renderer process will be crashed intentionally with a "connection retry
failure" message if the reconnect fails 3 times in a row.
This change introduces a few minor CEF API behavior changes:
- A CefProcessMessage object cannot be reused after being passed to
SendProcessMessage.
- The |extra_info| argument to CefRenderProcessHandler::OnBrowserCreated may
now be NULL.
Where appropriate, we now utilize the default UTF string encoding format and
shared memory to reduce copies and conversions for the cross-process
transfer of arbitrary-length strings. For example, CefFrame::GetSource/GetText
now involves zero UTF conversions and zero copies in the browser process for
the CefString delivered to CefStringVisitor::Visit().
Nik Pavlov
Marshall Greenblatt