Instead of communicating with layout via messages, script can simply
call methods on the layout trait. This simplifies the way that script
communicates with layout and opens the path to sharing more data
structures between the two systems. This is part of a continuing
series of cleanups after removing the layout thread.
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This change contains three semi-related clean ups:
1. the `to_webrender()` and `from_webrender()` functions on Pipeline are
turned into more-idiomatic `From` and `Into` implementations.
2. `combine_id_with_fragment_type` now returns a `u64` as that is what is
expected for all callers and not a `usize`.
3. The `query_scroll_id` query is removed entirely. The
`ExternalScrollId` that this queries is easily generated directly
from the node's opaque id. Querying into layout isn't necessary at
all.
The only font relative unit that Servo knows how to resolve currently is
`rem` (relative to the root font size). This is because Stylo cannot do
any font queries. This adds a mechanism to allow this, exposing the
ability to properly render `ex` units in Servo.
This change only allows resolving some font size relative units thoug,
as Servo doesn't collect all the FontMetrics it needs to resolve them
all. This capability will be added in followup changes.
Some new tests fail:
- ex-unit-001.html: This test fails because Servo does not yet have
support for setting the weight using @font-face rules on web fonts.
- ex-unit-004.html: This test fails because Servo does not yet have
support for setting the Unicode range of a web font using @font-face
rules.
- first-available-font-001.html: This test fails because the above
two feature are missing.
This change splits the style and layout data in DOM nodes that is
populated by style and layout passes. This makes Servo's data design
more like Gecko's. This allows:
1. Removing the various `StyleAndLayout` data structures used by layout.
2. Removing the `GetStyleAndLayoutData` and
`GetStyleAndOpaqueLayoutData` traits. Accessing style and layout data
are now just functions on the `LayoutNode` and `ThreadSafeLayoutNode`
traits.
3. Styling now doesn't populate layout data. This is is postponed until
layout itself.
4. Allows the DOM wrappers to no longer have to be generic over the
layout data. This data was already stored using `std::any::Any` and
the new code just makes layout responsible for downcasting. Cleaning
up the generic type parameter in the DOM wrappers can happen in a
followup change.
The main benefit to all of this is that we should be able to remove
unsafe creation of `ServoLayoutNode` in layout and
`TrustedLayoutNodeAddress` entirely, because `ServoLayoutNode` will be
able to be passed directly from script to layout. In addition, this
removes one more abstraction layer from the layout DOM wrappers, making
the code a lot more understandable.
Note: This increases the measured size of DOM types, but the same data
is stored. It's simply that before that data was stored behind a heap
pointer.
Remove the use of unsafe code in the layout wrappers of the DOM. The
main change here is that `unsafe_get()` no longer needs to be an unsafe
method, which allows us to transitively remove or reduce unsafe blocks
from callers. The function itself is not renamed, because it's still
a bit dangerous to start removing the layers of abstraction from actual
DOM nodes.
In addition `init_style_and_opaque_layout_data` can be merged into
`initialize_data`, which removes one more unsafe method.
Finally, a "Safety" section is added to some unsafe methods.
Instead of the tricky `LayoutRPC` interface, query layout using the
`Layout` trait. This means that now queries will requires calling layout
and then running the query. During layout an enum is used to indicate
what kind of layout is necessary.
This change also removes the mutex-locked `rw_data` from both layout
threads. It's no longer necessary since layout runs synchronously. The
one downside here is that for resolved style queries, we now have to
create two StyleContexts. One for layout and one for the query itself.
The creation of this context should not be very expensive though.
`LayoutRPC` used to be necessary because layout used to run
asynchronously from script, but that no longer happens. With this
change, it becomes possible to safely pass nodes to layout from script
-- a cleanup that can happen in a followup change.
This change also makes two fixes that are necessary to get WOFF2 fonts
working:
1. It adds support for loading web fonts from stylesheets included via
@import rules.
2. It ensure that when web fonts are loaded synchronusly they invalidate
the font cache. This led to incorrect font rendering when running
tests before.
Fixes#31598.
* Updated comment with 'layout_traits' to 'script_layout_interface'
* Rewrap text
* Remove trailing whitespace
---------
Co-authored-by: Martin Robinson <mrobinson@igalia.com>
* Remove packages that were moved to external repo
* Add workspace dependencies pointing to 2023-06-14 branch
* Fix servo-tidy.toml errors
* Update commit to include #31346
* Update commit to include servo/stylo#2
* Move css-properties.json lookup to target/doc/stylo
* Remove dependency on vendored mako in favour of pypi dependency
This also removes etc/ci/generate_workflow.py, which has been unused
since at least 9e71bd6a70.
* Add temporary code to debug Windows test failures
* Fix failures on Windows due to custom target dir
* Update commit to include servo/stylo#3
* Fix license in tests/unit/style/build.rs
* Document how to build with local Stylo in Cargo.toml
In quirks mode, preserved segment breaks should add line height to
lines. This matches the behavior of WebKit and Blink, but not Gecko.
This also handles the special-case of `<br>` elements, which are
implemented with preserved segment breaks via `white-space: pre-line`.
This is an implementation detail though because `<br>` has a special
behavior if the line isn't empty -- it doesn't add any line height in
this case.
* script: Do not run layout in a thread
Instead of spawning a thread for layout that almost always runs
synchronously with script, simply run layout in the script thread.
This is a resurrection of #28708, taking just the bits that remove the
layout thread. It's a complex change and thus is just a first step
toward cleaning up the interface between script and layout. Messages are
still passed from script to layout via a `process()` method and script
proxies some messages to layout from other threads as well.
Big changes:
1. Layout is created in the script thread on Document load, thus every
live document is guaranteed to have a layout. This isn't completely
hidden in the interface, but we can safely `unwrap()` on a Document's
layout.
2. Layout configuration is abstracted away into a LayoutConfig struct
and the LayoutFactory is a struct passed around by the Constellation.
This is to avoid having to monomorphize the entire script thread
for each layout.
3. Instead of having the Constellation block on the layout thread to
figure out the current epoch and whether there are pending web fonts
loading, updates are sent synchronously to the Constellation when
rendering to a screenshot. This practically only used by the WPT.
A couple tests start to fail, which is probably inevitable since removing
the layout thread has introduced timing changes in "exit after load" and
screenshot behavior.
Co-authored-by: Josh Matthews <josh@joshmatthews.net>
* Update test expectations
* Fix some issues found during review
* Clarify some comments
* Address review comments
---------
Co-authored-by: Josh Matthews <josh@joshmatthews.net>
This adds support for table rows, columns, rowgroups and colgroups.
There are few additions here:
1. The createion of fragments, which allows script queries and hit
testing to work properly. These fragments are empty as all cells are
still direct descendants of the table fragment.
2. Properly handling size information from tracks and track groups as
well as frustrating rules about reordering rowgroups.
3. Painting a background seemlessly across track groups and groups. This
is a thing that isn't done in legacy layout (nor WebKit)!
Co-authored-by: Oriol Brufau <obrufau@igalia.com>
The new strategy for dependencies with upstream in Gecko is to manage
them in separate repositories, which will more easily allow rebasing our
changes on top of newer Gecko work.
* Add initial support for sticky positioning for non-legacy layout
Many tests still fail for a variety of reasons. One of the primary ones
is that CSSOM currently does not return correct values for elements
positioned by sticky nodes. This requires changes to WebRender to work
properly.
* Fix an assertion failure in the legacy layout sticky code
This is the start of the organization of types that are in their own
crates in order to break dependency cycles between other crates. The
idea here is that putting these packages into their own directory is the
first step toward cleaning them up. They have grown organically and it
is difficult to explain to new folks where to put new shared types. Many
of these crates contain more than traits or don't contain traits at all.
Notably, `script_traits` isn't touched because it is vendored from
Gecko. Eventually this will move to `third_party`.
