This patch implements mozilla::NotNull, which is similar but not identicial to
gsl::not_null.
The current draft(?) implementation of gsl::not_null is at
https://github.com/Microsoft/GSL/blob/master/include/gsl.h.
The main difference is that not_null allows implicit conversion from T to
not_null<T>. In contrast, NotNull only allows explicit conversion from T to
NotNull<T> via WrapNotNull().
The rationale for this is that when converting from a less-constrained type to
a more constrained type, implicit conversion is undesirable. For example, if I
changed a function f from this:
f(int* aPtr);
to this:
f(gsl::not_null<int*> aPtr);
no call sites would have to be modified. But if I changed it to this:
f(mozilla::NotNull<int*> aPtr);
call sites *would* need to be modified. This is a good thing! It forces the
author to audit the call sites for non-nullness, and encourages them to
back-propagate NotNull throughout the code.
The other difference between not_null and NotNull is that not_null disables
pointer arithmetic, which means it cannot be used with array pointers. I have
not implemented this restriction for NotNull because it seems arbitrary and
unnecessary.
It's an annotation that is used a lot, and should be used even more, so a
shorter name is better.
MozReview-Commit-ID: 1VS4Dney4WX
--HG--
extra : rebase_source : b26919c1b0fcb32e5339adeef5be5becae6032cf
Writing PopLastN in this way is probably a bit of a micro-optimization,
but at least it comes with tests and some comments for verifying the
goodness of the code.
The scheme in TestSegmentedVectors to use manually-annotated points and
magic numbers corresponding to those annotations works OK for small
numbers of operations. But for testing bulk push and pop, we're going
to be doing many more operations, so let's move to recording explicitly
in code the operations we expect to see, and checking those instead.
The bulk of this commit was generated with a script, executed at the top
level of a typical source code checkout. The only non-machine-generated
part was modifying MFBT's moz.build to reflect the new naming.
CLOSED TREE makes big refactorings like this a piece of cake.
# The main substitution.
find . -name '*.cpp' -o -name '*.cc' -o -name '*.h' -o -name '*.mm' -o -name '*.idl'| \
xargs perl -p -i -e '
s/nsRefPtr\.h/RefPtr\.h/g; # handle includes
s/nsRefPtr ?</RefPtr</g; # handle declarations and variables
'
# Handle a special friend declaration in gfx/layers/AtomicRefCountedWithFinalize.h.
perl -p -i -e 's/::nsRefPtr;/::RefPtr;/' gfx/layers/AtomicRefCountedWithFinalize.h
# Handle nsRefPtr.h itself, a couple places that define constructors
# from nsRefPtr, and code generators specially. We do this here, rather
# than indiscriminantly s/nsRefPtr/RefPtr/, because that would rename
# things like nsRefPtrHashtable.
perl -p -i -e 's/nsRefPtr/RefPtr/g' \
mfbt/nsRefPtr.h \
xpcom/glue/nsCOMPtr.h \
xpcom/base/OwningNonNull.h \
ipc/ipdl/ipdl/lower.py \
ipc/ipdl/ipdl/builtin.py \
dom/bindings/Codegen.py \
python/lldbutils/lldbutils/utils.py
# In our indiscriminate substitution above, we renamed
# nsRefPtrGetterAddRefs, the class behind getter_AddRefs. Fix that up.
find . -name '*.cpp' -o -name '*.h' -o -name '*.idl' | \
xargs perl -p -i -e 's/nsRefPtrGetterAddRefs/RefPtrGetterAddRefs/g'
if [ -d .git ]; then
git mv mfbt/nsRefPtr.h mfbt/RefPtr.h
else
hg mv mfbt/nsRefPtr.h mfbt/RefPtr.h
fi
--HG--
rename : mfbt/nsRefPtr.h => mfbt/RefPtr.h
This commit was generated using the following script, executed at the
top level of a typical source code checkout.
# Don't modify select files in mfbt/ because it's not worth trying to
# tease out the dependencies currently.
#
# Don't modify anything in media/gmp-clearkey/0.1/ because those files
# use their own RefPtr, defined in their own RefCounted.h.
find . -name '*.cpp' -o -name '*.h' -o -name '*.mm' -o -name '*.idl'| \
grep -v 'mfbt/RefPtr.h' | \
grep -v 'mfbt/nsRefPtr.h' | \
grep -v 'mfbt/RefCounted.h' | \
grep -v 'media/gmp-clearkey/0.1/' | \
xargs perl -p -i -e '
s/mozilla::RefPtr/nsRefPtr/g; # handle declarations in headers
s/\bRefPtr</nsRefPtr</g; # handle local variables in functions
s#mozilla/RefPtr.h#mozilla/nsRefPtr.h#; # handle #includes
s#mfbt/RefPtr.h#mfbt/nsRefPtr.h#; # handle strange #includes
'
# |using mozilla::RefPtr;| is OK; |using nsRefPtr;| is invalid syntax.
find . -name '*.cpp' -o -name '*.mm' | xargs sed -i -e '/using nsRefPtr/d'
# RefPtr.h used |byRef| for dealing with COM-style outparams.
# nsRefPtr.h uses |getter_AddRefs|.
# Fixup that mismatch.
find . -name '*.cpp' -o -name '*.h'| \
xargs perl -p -i -e 's/byRef/getter_AddRefs/g'
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.
The patch removes 455 occurrences of FAIL_ON_WARNINGS from moz.build files, and
adds 78 instances of ALLOW_COMPILER_WARNINGS. About half of those 78 are in
code we control and which should be removable with a little effort.
--HG--
extra : rebase_source : 82e3387abfbd5f1471e953961d301d3d97ed2973
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.
CLOSED TREE
Backed out changeset 12ce98475c6e (bug 1119980)
Backed out changeset bdb8d05f8870 (bug 1119980)
Backed out changeset a68a18840492 (bug 1119980)
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.
Note that the analysis currently just looks at the AST subtree of the
function call site and is therefore unable to correctly deal with cases
such as the last two hunks of the change to OggCodecState.cpp. Fixing
the analysis to deal with that would be very difficult, so we currently
adjust the code so that it compiles. The first hunk in that file though
is a real bug that this analysis found.
Note that the analysis currently just looks at the AST subtree of the
function call site and is therefore unable to correctly deal with cases
such as the last two hunks of the change to OggCodecState.cpp. Fixing
the analysis to deal with that would be very difficult, so we currently
adjust the code so that it compiles. The first hunk in that file though
is a real bug that this analysis found.
--HG--
extra : rebase_source : b44bb6d90d95551d860e0b5a1afcf2bb35cde084
There are, sadly, many combinations of linkage in use throughout the tree.
The main differentiator, though, is between program/libraries related to
Gecko or not. Kind of. Some need mozglue, some don't. Some need dependent
linkage, some standalone.
Anyways, these new templates remove the need to manually define the
right dependencies against xpcomglue, nspr, mozalloc and mozglue
in most cases.
Places that build programs and were resetting MOZ_GLUE_PROGRAM_LDFLAGS
or that build libraries and were resetting MOZ_GLUE_LDFLAGS can now
just not use those Gecko-specific templates.
Andi-Bogdan Postelnicu
Nicholas Nethercote
Chris Peterson
Bill McCloskey
Jon Coppeard
Carsten "Tomcat" Book
Terrence Cole
Benoit Girard
Ehsan Akhgari
Nick Fitzgerald
Nathan Froyd
Thomas Zimmermann
Xidorn Quan
Jeff Muizelaar
Jan de Mooij
Botond Ballo
Jeff Walden
Birunthan Mohanathas
Steve Fink
James Cheng
Jim Blandy
Wes Kocher
Jared Wein
Phil Ringnalda
Jeff Gilbert
Kan-Ru Chen
Liang-Heng Chen
Bobby Holley
Gerald Squelart
Andrew McCreight
Trevor Saunders
Seth Fowler
Seth Fowler
Masatoshi Kimura
Trevor Saunders
Ryan VanderMeulen
Matthew Gregan
Mike Hommey