A lot of this is quite ugly, but it should only be so until I remove
Length::Type::Percentage entirely. (Which should happen later in this
PR, otherwise, yell at me!) For now, a lot of things have to be
resolved twice, first from a LengthPercentage to a Length, and then
from a Length to a pixel one.
The flexbox logic confuses me so regressions are possible, though our
test page looks the same as before so it should be fine.
Renamed FlexBasis::Length -> LengthPercentage too, for clarity.
This does undo the changes in 88c32836d8,
which accounted for our bitmap fonts being a different size than the
`font-size` property requests. I think this would be better handled
inside Length::to_px(), which would then apply to all font-size-relative
lengths (eg, em and rem) instead of only for the line-height property.
Layout::Node still treats border radii as having a single value instead
of horizontal and vertical, but one less hack is nice, and helps with
conversion to LengthPercentage. :^)
This is in a slightly weird state, where Percentages are sometimes
Lengths and sometimes not, which I will be cleaning up in subsequent
commits, in an attempt not to change all of LibWeb in one go. :^)
Length and Percentage are different types, and sometimes only one or the
other is allowed in a given CSS property. This is a first step towards
separating them.
This is in line with this recent change to Conditional-3:
> Removed the “unknown” value in CSS feature queries’ boolean logic,
> defining unrecognized syntaxes as “false” instead.
> https://github.com/w3c/csswg-drafts/issues/6175
This change unfortunately cannot be atomically made without a single
commit changing everything.
Most of the important changes are in LibIPC/Connection.cpp,
LibIPC/ServerConnection.cpp and LibCore/LocalServer.cpp.
The notable changes are:
- IPCCompiler now generates the decode and decode_message functions such
that they take a Core::Stream::LocalSocket instead of the socket fd.
- IPC::Decoder now uses the receive_fd method of LocalSocket instead of
doing system calls directly on the fd.
- IPC::ConnectionBase and related classes now use the Stream API
functions.
- IPC::ServerConnection no longer constructs the socket itself; instead,
a convenience macro, IPC_CLIENT_CONNECTION, is used in place of
C_OBJECT and will generate a static try_create factory function for
the ServerConnection subclass. The subclass is now responsible for
passing the socket constructed in this function to its
ServerConnection base; the socket is passed as the first argument to
the constructor (as a NonnullOwnPtr<Core::Stream::LocalServer>) before
any other arguments.
- The functionality regarding taking over sockets from SystemServer has
been moved to LibIPC/SystemServerTakeover.cpp. The Core::LocalSocket
implementation of this functionality hasn't been deleted due to my
intention of removing this class in the near future and to reduce
noise on this (already quite noisy) PR.
Instead of making it a void function, checking for an exception, and
then receiving the relevant result via VM::last_value(), we can
consolidate all of this by using completions.
This allows us to remove more uses of VM::exception(), and all uses of
VM::last_value().
This includes:
- Parsing proper LabelledStatements with try_parse_labelled_statement()
- Removing LabelableStatement
- Implementing the LoopEvaluation semantics via loop_evaluation() in
each IterationStatement subclass; and IterationStatement evaluation
via {For,ForIn,ForOf,ForAwaitOf,While,DoWhile}Statement::execute()
- Updating ReturnStatement, BreakStatement and ContinueStatement to
return the appropriate completion types
- Basically reimplementing TryStatement and SwitchStatement according to
the spec, using completions
- Honoring result completion types in AsyncBlockStart and
OrdinaryCallEvaluateBody
- Removing any uses of the VM unwind mechanism - most importantly,
VM::throw_exception() now exclusively sets an exception and no longer
triggers any unwinding mechanism.
However, we already did a good job updating all of LibWeb and userland
applications to not use it, and the few remaining uses elsewhere don't
rely on unwinding AFAICT.
This requires an implementation of the "text preparation algorithm" as
specified here:
html.spec.whatwg.org/multipage/canvas.html#text-preparation-algorithm
However, we're missing a lot of things such as the
CanvasTextDrawingStyles interface, so most of the algorithm was not
implemented. Additionally, we also are not able to use a LineBox like
the algorithm suggests, because our layouting infra is not up to the
task yet. The prepare_text function does nothing other than figuring out
the width of the given text and return glyphs with offsets at the
moment.
In the end this is a nicer API than having separate has_{value,target}()
and having to check those first, and then making another Optional from
the unwrapped value:
completion.has_value() ? completion.value() : Optional<Value> {}
// ^^^^^^^^^^^^^^^^^^
// Implicit creation of non-empty Optional<Value>
This way we need to unwrap the optional ourselves, but can easily pass
it to something else as well.
This is in anticipation of the AST using completions :^)
This means you can now do queries like:
```css
@media (400px <= width < 800px) { }
```
Chromium and Firefox which I tested with both don't support this yet, so
that's cool. :^)
Past me decided that the grammar was overly verbose and I could do it
better myself. Which seemed fine until the spec changed and I didn't
know how to integrate the changes. Lesson learned! :^)
Rather than have a function for every single part of the grammar, I have
written some as lambdas, and combned `<media-condition>` and
`<media-condition-without-or>` into one function. But otherwise it's
close to the spec, with comments listing the part of the grammar being
parsed, so hopefully it will be easier to make future adjustments!
This does not add any new functionality.
Web::CSS::MediaQuery::MediaFeature::Type was getting a bit ridiculous!
Also, this moves the detection of "min-" and "max-" media-features into
the MediaFeature itself, since this is an implementation detail, not
part of the spec.
Having these in here was a hack to support the other hack of making
media-queries use StyleValues. Now they don't do that, so we can remove
these again and keep things hygienic.
Previously, we were using StyleValues for this, which was a bit of a
hack and was brittle, breaking when I modified how custom properties
were parsed. This is better and also lets us limit the kinds of value
that can be used here, to match the spec.
This means we can get rid of the hacks where we were peeking a code
point instead of getting the next one so that we could peek_twin()
later. Now, we follow the spec more closely. :^)
This fixes the crash that Luke found using Domato:
```css
. foo {
mso-border-alt: solid .-1pt;
}
```
The spec distinguishes between "If the next 3 code points would
start..." and "If the input stream starts with..." but we were treating
them the same way, skipping the first code point in the process.
These correspond to "If the input stream starts with..." in the spec,
which up until now we were not handling correctly, which led to some fun
bugs.
As noted, reconsuming the input code point in order to read its value is
hacky, but works. Keeping track of the current code point in Tokenizer
would be nicer, when I'm feeling brave enough to mess with it!
This will allow us to easily add copies of the relevant canvas drawing
state to a stack, and likewise replace the current drawing state with
an entry from that stack.
I don't know if the original author simply missed this or thought the
default color of Gfx::Color is black, but this meant that drawing on a
canvas without explicitly setting a fillStyle or strokeStyle first would
be drawn in transparent color and therefore be invisible.
In the spec this is indicated by a small comment in the IDL definition:
attribute ... strokeStyle; // (default black)
attribute ... fillStyle; // (default black)
I'm starting to question whether Gfx::Color actually *should* have a
default constructor.
