When we create a WebDriverConnection object, we currently hand it the
page client for which it was opened, and perform all actions on that
client. However, some WebDriver endpoints change the browsing context
(and therefore page client) on which future commands should be executed.
For example, the switch-frame endpoint will switch the current browsing
context to a frame/iframe context.
This patch implements the current browsing context (and current top-
level browsing context) concepts. They are initialized to that of the
original page. Most of this patch is making sure we execute actions on
the correct context.
We currently spin the platform event loop while awaiting scripts to
complete. This causes WebContent to hang if another component is also
spinning the event loop. The particular example that instigated this
patch was the navigable's navigation loop (which spins until the fetch
process is complete), triggered by a form submission to an iframe.
So instead of spinning, we now return immediately from the script
executors, after setting up listeners for either the script's promise to
be resolved or for a timeout. The HTTP request to WebDriver must finish
synchronously though, so now the WebDriver process spins its event loop
until WebContent signals that the script completed. This should be ok -
the WebDriver process isn't expected to be doing anything else in the
meantime.
Also, as a consequence of these changes, we now actually handle time
outs. We were previously creating the timeout timer, but not starting
it.
Use this cached pointer to the containing block's used values when
obviously possible. This avoids a hash lookup each time, and these
hash lookups do show up in profiles.
Change try_compute_width() to check whether min-width/max-width or width
is auto instead of always using `computed_values.width()`.
`grid/min-max-content.html` test is affected but it's progression.
UI event handlers currently return a boolean where false means the event
was cancelled by a script on the page, or otherwise dropped. It has been
a point of confusion for some time now, as it's not particularly clear
what should be returned in some special cases, or how the UI process
should handle the response.
This adds an enumeration with a few states that indicate exactly how the
WebContent process handled the event. This should remove all ambiguity,
and let us properly handle these states going forward.
There should be no behavior change with this patch. It's meant to only
introduce the enum, not change any of our decisions based on the result.
Logging a parse error when the attribute is not present, is not useful,
but does fill the debug log with errors that hide any real parsing
errors. This patch introduces an early-out in this situation to prevent
this spam.
The following spec algorithms had changed since we implemented them:
- "parse a sizes attribute"
- "update the source set"
- "create a source set"
This commit brings them up to date, as well as adding some additional
logging when parsing the sizes attribute fails in some way.
Before this change, a formatting context was responsible for layout of
absolutely positioned boxes whose FC root box was their parent (either
directly or indirectly). This only worked correctly when the containing
block of the absolutely positioned child did not escape the FC root.
This is because the width and height of an absolutely positioned box are
resolved based on the size of its containing block, so we needed to
ensure that the containing block's layout was completed before laying
out an absolutely positioned box.
With this change, the layout of absolutely positioned boxes is delayed
until the FC responsible for the containing block's layout is complete.
This has affected the way we calculate the static position. It is no
longer possible to ask the FC for a box's static position, as this FC's
state might be gone by the time the layout for absolutely positioned
elements occurs. Instead, the "static position rectangle" (a concept
from the spec) is saved in the layout state, along with information on
how to align the box within this rectangle when its width and height are
resolved.
Absolutely positioned boxes do not affect the size of the formatting
context box they belong to, so it's safe to skip their layout entirely
when calculating intrinsic size.
FormattingContext::run() does not allow reentrancy, so it's safe to
save and access layout mode from FC object. This avoids need to drill it
through methods of a formatting context and makes it clear that this
value could never be changed after FC construction.
Root formatting context box is passed into constructor and saved in FC,
so it's possible to access it from there instead of passing the same
box into run().
This change takes all existing WebIDL files in the repo that had
definition lines without four leading spaces, and fixes them so they
have four leading spaces.
This change ensures that the value sanitization algorithm is run and
the text cursor is set to the correct position when the type attribute
of an input is changed.
Instead of throwing all pseudo-element rules in one bucket, let's have
one bucket per pseudo-element.
This means we only run ::before rules for ::before pseudo-elements,
only ::after rules for ::after, etc.
Average style update time on https://tailwindcss.com/ 250ms -> 215ms.
Once we know the final value of the `content` property for a
pseudo-element, we can bail early if the value is `none` or `normal`
(note that `normal` only applies to ::before and ::after).
In those cases, no pseudo-element will be generated, so everything
that follows in StyleComputer would be wasted work.
This noticeably improves performance on many pages, such as
https://tailwindcss.com/ where style updates go from 360ms -> 250ms.
This makes the way we've implemented the CSS `revert` keyword a lot less
expensive.
Until now, we were making a deep copy of all property values at the
start of each cascade origin. (Those are the values that `revert` would
bring us back to if encountered.)
With this patch, the revert property set becomes a shallow copy, and we
only clone the property set if the cascade ends up writing something.
This knocks a 5% profile item down to 1.3% on https://tailwindcss.com
Instead of asking Skia for the family name every time we're called,
just cache the string once and make subsequent calls fast.
This knocks a 3.2% item off the profile entirely on
https://tailwindcss.com (at least on macOS with the CoreText backend)
This brings back the optimization we had in the old OpenType
implementation where we cache lookup tables for code point / glyph ID
mappings.
This noticeably improves performance on https://tailwindcss.com/ by
knocking an 8% profile item down to 0.2%. :^)
