On Fri, Mar 18, 2016 at 11:07 AM, <jww...@mozilla.com> wrote: > > https://hg.mozilla.org/mozilla-central/file/3e04659fdf6aef792f7cf9840189c6c38d08d1e8/mfbt/UniquePtr.h#l182 > > "To unconditionally transfer ownership of a UniquePtr into a method, use a > |UniquePtr| argument. To conditionally transfer ownership of a resource > into a method, should the method want it, use a |UniquePtr&&| argument." > > Does that also apply to already_AddRefed<>&& or we stick to > https://bugzilla.mozilla.org/show_bug.cgi?id=1247972#c19? > > Btw, we have some code like > https://hg.mozilla.org/mozilla-central/file/3e04659fdf6aef792f7cf9840189c6c38d08d1e8/dom/base/WebSocket.cpp#l2790 > where it really should be just already_AddRefed<> since the ownership is > always transferred. >
I used already_AddRefed<>&& (and even UniquePtr<>&&) for parameters for unconditional transfer for quite a while. But I'm recently convinced that we should use already_AddRefed<> and UniquePtr<> in almost all cases, because compilers actually have more chance to optimize code with them rather than &&. I believe conditional move is rare, and could be confusing in most cases, and you may actually want to use T& rather than T&& for conditional move. The only use of && is for move-constructor and functions we want people to reconsider when they try to pass in lvalue. - Xidorn _______________________________________________ dev-platform mailing list dev-platform@lists.mozilla.org https://lists.mozilla.org/listinfo/dev-platform
