Various bits depend on RefPtr.h to provide RefCounted<T> and RefPtr<T>.
It will be easier to manage an automatic conversion from RefPtr<T> to
nsRefPtr<T> if we split out the dependency on RefCounted<T> first.
RefPtr.h's byref permits callees to see the incoming value of the
outparam; XPCOM's getter_AddRefs zeros outparams prior to the call, so
information doesn't leak through inadvertently. Given this difference,
we need to eliminate tests that depended on this (arguably dangerous)
behavior. The numerous assertion fixups are required because we're
removing construction and destruction of objects along the way.
This conversion was done with the script:
find . -name '*.cpp' -o -name '*.h' -o -name '*.mm' -o -name '*.idl' | \
egrep -v 'cairo-win32-refptr.h|RefPtr.h|TestRefPtr.cpp' | \
xargs sed -i -e 's/mozilla::TemporaryRef</already_AddRefed</g' \
-e 's/TemporaryRef</already_AddRefed</g'
Manual fixups were performed in the following instances:
- We handled mfbt/RefPtr.h manually so as to not convert TemporaryRef itself
into already_AddRefed.
- The following files had explicit Move() calls added to make up for the lack
of a copy constructor on already_AddRefed:
dom/base/ImageEncoder.cpp
dom/media/MediaTaskQueue.{h,cpp}
dom/media/webaudio/PannerNode.cpp
- A redundant overload for MediaTaskQueue::Dispatch was deleted.
- A few manual fixups were required in mfbt/tests/TestRefPtr.cpp.
- Comments, using declarations, and forward declarations relating to
TemporaryRef in dom/canvas/ and gfx/layers/ were changed to refer to
already_AddRefed.
Having this implicit conversion means that we can silently do extra
refcounting when it's completely unnecessary. It's also an obstacle to
making RefPtr more nsRefPtr-like, so let's get rid of it.
Nathan Froyd
Nicholas Nethercote