This also effectively changes how DMD is enabled from requiring both
replace-malloc initialization and the DMD environment variable to
requiring only the former. The DMD environment variable can still be
used to specify options, but not to disable entirely.
This however doesn't touch all the parts that do enable DMD by setting
the DMD environment variable to 1, so the code to handle this value
is kept.
Doing this means that instantiations of nsRefPtr<T> won't require
nsCOMPtr_helper::operator() to be defined. Only actual uses of the
overloads will require the definition.
The interesting feature JSONWriteFunc has, contrary to JSONWriter, is that it
only has virtual methods, which makes it a better candidate to be passed
around between libraries not linked against each other.
This will allow to make dmd and libxul independent from each other.
This patch does the following.
- Moves the logic for computing the ideal capacity for a SegmentedArray out of
SnowWhiteKiller into its own class, SegmentedArrayCapacity.
- Replaces the nsTArray in CollectWhite(), which can be very large and is
complicit in ~1% of OOM crashes, with a SegmentedArray.
--HG--
extra : rebase_source : 732743311a08fcc3dfe43a1b308846b93d30e6ed
This patch generalizes SegmentedArray a little, and then uses it instead of
nsTArray in SnowWhiteKiller. This avoids some large (sometimes 1 MiB or more)
allocations which were usually mostly unused.
This adds "hasSeccompBPF" for seccomp-bpf support; other "has" keys
will be added in the future (e.g., user namespaces).
This also adds "canSandboxContent" and "canSandboxMedia", which are
absent if the corresponding type of sandboxing isn't enabled at build
type (or is disabled with environment variables), and otherwise present
as a boolean indicating whether that type of sandboxing is supported.
Currently this is always the same as hasSeccompBPF, but that could change
in the future.
Some changes have been made to the "mozilla/Sandbox.h" interface to
support this; the idea is that the MOZ_DISABLE_*_SANDBOX environment
variables should be equivalent to disabling MOZ_*_SANDBOX at build time.
Root() does not actually root JS things, so if some other class's Unlink() method ends
up calling the GC, whiteNodes will end up containing dead pointers. (This is safe right
now because the Unlink and Unroot methods do not do anything to JS things.) It is less
error prone to simply never store those pointers.
Also, add some asserts to enforce that we never call any of the white-object methods
for JS things.
If an Unlink() method ends up running JS, it can cause a GC, which will make us reenter the CC,
which will not do anything because we're already in a CC. Therefore, FinishAnyCurrentCollection()
won't finish the CC. This is safe because the CC only touches things it actually holds alive via
the Root() method.
