Structs in our style system use an arena-style allocation system,
managed by the presshell to which they belong. All of the relevant
overloads that forward allocation requests to the presshell declare
themselves as CPP_THROW_NEW, which indicates that they do not throw
exceptions. The C++ specification states that operator new overloads
that declare themselves to not throw exceptions require a null check on
their return value. However, the relevant presshell allocation method,
AllocateByObjectID, is infallible and will never return a null pointer.
The callers of all of these methods are therefore doing useless
(compiler-generated) null checks. Let's get rid of those useless checks
by removing the CPP_THROW_NEW annotations. This change declares these
methods will return non-null pointers and throw exceptions in case of
errors--but as we don't use exceptions, and AllocateByObjectID will
abort on OOM, everything works out OK.
Structs in our style system use an arena-style allocation system,
managed by the presshell to which they belong. All of the relevant
overloads that forward allocation requests to the presshell declare
themselves as CPP_THROW_NEW, which indicates that they do not throw
exceptions. The C++ specification states that operator new overloads
that declare themselves to not throw exceptions require a null check on
their return value. However, the relevant presshell allocation method,
AllocateByObjectID, is infallible and will never return a null pointer.
The callers of all of these methods are therefore doing useless
(compiler-generated) null checks. Let's get rid of those useless checks
by removing the CPP_THROW_NEW annotations. This change declares these
methods will return non-null pointers and throw exceptions in case of
errors--but as we don't use exceptions, and AllocateByObjectID will
abort on OOM, everything works out OK.
The bulk of this commit was generated by running:
run-clang-tidy.py \
-checks='-*,llvm-namespace-comment' \
-header-filter=^/.../mozilla-central/.* \
-fix
"new nsFrameList()" becomes "new (shell) nsFrameList()".
"delete list" becomes "if (list) list->Delete(shell)" - note also that
an additional assertion was added that list is empty when deleted.
"nsAutoPtr<nsFrameList> list(StealSomeFrames())" becomes
"AutoFrameListPtr list(aPresContext, StealSomeFrames())"
* we know all types frames may be cast to at compile time, so instead of extensible GUID IIDs, use a big enum (see nsQueryFrame::FrameIID)
* eliminate all vestiges of refcounting, since frames aren't refcounted
Some frames (SVG frames in particular) still implement nsISupports-derived interfaces, for example nsISVGValue. There is a FrameIID for nsISVGValue that lets you go from a frame to the XPCOM interface, but you can't query back.
r+sr=roc
nsITextControlFrame didn't have an IID the first time around, but this wasn't a compile error because nsITextControlFrame::kFrameIID inherited from nsIFormControlFrame::kFrameIID. I've added a static analysis pass to verify the correct behavior, since I can't figure out a way to make the compiler do it.
--HG--
extra : rebase_source : 4894a2ca0278e2ab92f27459db77165f8348cf41
Nathan Froyd
Wes Kocher
Cameron McCormack
Birunthan Mohanathas
Jonathan Kew
Simon Montagu
Mats Palmgren
Ehsan Akhgari
Timothy Nikkel
Ehsan Akhgari
Aryeh Gregor
Gervase Markham
Daniel Holbert
Michael Wu
Craig Topper
L. David Baron
Ehren Metcalfe
fantasai
Robert O'Callahan
Boris Zbarsky
Zack Weinberg
Arpad Borsos
Benjamin Smedberg