If a calculation was simplified down to a single numeric node, then most
of the time we can instead return a regular StyleValue, for example
`calc(2px + 3px)` would be simplified down to a `5px` LengthStyleValue.
This means that parse_calculated_value() can't return a
CalculatedStyleValue directly, and its callers all have to handle
non-calculated values as well as calculated ones.
This simplification is reflected in the new test results. Serialization
is not yet correct in all cases but we're closer than we were. :^)
Calc simplification (which I'm working towards) involves repeatedly
deriving a new calculation tree from an existing one, and in many
cases, either the whole result or a portion of it will be identical to
that of the original. Using RefPtr lets us avoid making unnecessary
copies. As a bonus it will also make it easier to return either `this`
or a new node.
In future we could also cache commonly-used nodes, similar to how we do
so for 1px and 0px LengthStyleValues and various keywords.
`current_property_id()` is insufficient to determine if a quirk is
allowed. For example, unitless lengths are allowed in certain
properties, but NOT if they are inside a calc() or other function. It's
also incorrect when we are parsing a longhand inside a shorthand. So
instead, replace that with a stack of value-parsing contexts. For now,
this is either properties or CSS functions, but in future can be
expanded to include media features and other places.
This lets us disallow quirks inside functions, like we're supposed to.
It also lays the groundwork for being able to more easily determine
what type a percentage inside a calculation should become, as this is
based on the same stack of contexts.
Rather than partly-converting number, dimension, and ident tokens at the
start of parsing a calculation, and then later finishing it off, we can
just do the whole step in convert_to_calculation_node(). This is a
little less code, but mainly means we are left with only a single use
of the Dimension type in the codebase, so that can be removed soon.
When we know what kind of dimension we want, it's awkward to attempt to
parse any dimension type, including quirks that only affect lengths, to
then throw it away unless it's the type we wanted in the first place.
Additionally, move the unitless angle/length behavior for SVG attributes
into these methods, where it belongs.
Instead, only try to parse the type of dimension we want. This is
currently more code, but some could be factored together later.
When we originally implemented calc(), the result of a calculation was
guaranteed to be a single CSS type like a Length or Angle. However, CSS
Values 4 now allows more complex type arithmetic, which is represented
by the CSSNumericType class. Using that directly makes us more correct,
and allows us to remove a large amount of now ad-hoc code.
Unfortunately this is a large commit but the changes it makes are
interconnected enough that doing one at a time causes test
regressions.
In no particular order:
- Update our "determine the type of a calculation" code to match the
newest spec, which sets percent hints in a couple more cases. (One of
these we're skipping for now, I think it fails because of the FIXMEs
in CSSNumericType::matches_foo().)
- Make the generated math-function-parsing code aware of the difference
between arguments being the same type, and being "consistent" types,
for each function. Otherwise those extra percent hints would cause
them to fail validation incorrectly.
- Use the CSSNumericType as the type for the CalculationResult.
- Calculate and assign each math function's type in its constructor,
instead of calculating it repeatedly on-demand.
The `CalculationNode::resolved_type()` method is now entirely unused and
has been removed.
This reverts commit 76daba3069.
We're going to need separate types for the JS-exposed style values, so
it doesn't make sense for us to match their names with our internal
types.
Previously we created a tree of CalculationNodes with dummy
UnparsedCalculationNode children, and then swapped those with the real
children. This matched the spec closely but had the unfortunate
downside that CalculationNodes couldn't be immutable, and couldn't know
their properties at construct-time. UnparsedCalculationNode is also a
footgun, as if it gets left in the tree accidentally we would VERIFY().
So instead, let's parse the calc() tree into an intermediate format, and
then convert each node in that tree, depth-first, into its
corresponding CalculationNode. This means each CalculationNode knows
what its children are when it is constructed, and they never change.
Apart from deleting UnparsedCalculationNode, we can also get rid of the
for_each_child_node() method that was only used by this "replace the
children" code.
When the "Consume a component value from input, and do nothing."
step in `Parser::consume_the_remnants_of_a_bad_declaration` was
executed, it would allocate a `ComponentValue` that was then
immediately discarded.
Add explicitly `{}_and_do_nothing` functions for this case that never
allocate a `ComponentValue` in the first place.
Also remove a `(Token)` cast, which was unnecessarily copying a `Token`
as well.
Resulting in a massive rename across almost everywhere! Alongside the
namespace change, we now have the following names:
* JS::NonnullGCPtr -> GC::Ref
* JS::GCPtr -> GC::Ptr
* JS::HeapFunction -> GC::Function
* JS::CellImpl -> GC::Cell
* JS::Handle -> GC::Root
