The basic idea here is as follows:
* Rule nodes are reference-counted, but releasing them adds them to a linked
list rather than freeing them. This allows for the reuse that motivated the
original GC scheme.
* We get rid of the marking, and instead rely on the reference count.
* Sweeping no longer requires a complicated traversal. We just pop items
off the free list until it's empty. When a child is destroyed, its parent
may go onto the free list.
* We remove special handling for the root node, and use a regular reference-counted
edge from the style set.
* The free list automatically asserts that it's empty (meaning all nodes have been
freed) in its destructor, which runs when the style set is destroyed.
* We get rid of the list of style context roots on the style set. We still need
a count though, because of the HasCachedStyleData check.
The only substantive change here, apart from a few variables changing in
size from uint16_t to uint8_t, is FontFaceSet's use of SheetType::Unknown
(0xFF) instead of 0 for FontFaceRecords for script-created FontFaces.
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
I confirmed that we're actually using this codepath by manually testing
<input type=color>: it works with the patch, but if I comment out the
call to nsHTMLCSSStyleSheet::PseudoElementRulesMatching from
nsStyleSet::RuleNodeWithReplacement, then the color swatch breaks, which
proves that we're depending on the code.
I think I included this in the queue because it is needed for patch 22,
although I've forgotten the full reasoning.
Without this patch, patch 3 will cause bugs where we'll never remove the
cover rule we create during the process of starting a transition. This
won't actually be problematic during the transition, since the
transition will overwrite it, but once the transition completes, the
cover rule will still be around, and we'll be stuck with the
pre-transition value instead of the post-transition value.
It's possible it also fixes existing bugs prior to the patch series in
this bug.
I will fix the indentation of gCascadeLevels in bug 977991 patch 2,
which adds a member to each element of the array.
Note that this bumps the maximum sheetType from 8 to 9 (and number of
them from 9 to 10), which does not require updating
NS_RULE_NODE_LEVEL_MASK, since NS_RULE_NODE_LEVEL_MASK currently has 4
bits and allows a maximum of 15.
This matches patch 2, and also fixes an incorrect use of eRestyle_Self
on the parents of pseudo-elements in order to restyle those
pseudo-elements, where it would not previously have been effective.
This should all be temporary, since this code can go away with bug
960465, when animation phases are removed.
ResolveStyleForRules had various problems: it failed to set importance
correctly and really only handled replacing a path in the rule tree
since it didn't handle creating important rules. (Possibly more.)
This means ResolveStyleWithReplacement will replace only the rules in
the nsRestyleHint rather than always replacing both the animations rule
and the transitions rule. (This will become even more useful later when
we add the ability to replace the style attribute rule.)
