This patch adds a second style dirty bit that tracks whether a DOM node
has one or more children with dirty style. This allows the style update
to skip over entire subtrees where all nodes are clean.
After you mark a node as needing new style, there's no situation in
which we don't want a style update to happen, so just take care of
scheduling it automatically.
From the Web IDL spec: https://heycam.github.io/webidl/#idl-undefined
[...]
undefined constant values in IDL are represented with the `undefined`
token.
[...]
Note: This value was previously spelled `void`, and more limited in how
it was allowed to be used.
Instead of invoking the CSS parser every time we compute the style for
an element that has a "style" attribute, we now cache the result of
parsing the inline style whenever the "style" attribute is set.
This is a nice boost to relayout performance since we no longer hit the
CSS parser at all.
I didn't generalize this into a helper since the HTML spec doesn't
seem to use this particular algorithm for anything else.
This makes the ACID1 test title show up correctly. :^)
The BFC "context box" is now the outer box of the block formatting
context. Previously the context box was always the current target box,
which made it hard to reason about who was really the containing block
of whom in various places.
Note that IFC still has the containing block as its context box, this
change only affects BFC. However, to clarify the situation in IFC,
I've added a containing_block() getter than returns the context_box().
Note that we're taking a shortcut here and returning the elements as an
Array instead of HTMLCollection. One day we'll have to bite the bullet
and deal with HTMLCollection, but not today.
Instead of hiding JS exceptions raised on the web, we now print them to
the debug log. This will make it a bit easier to work out why some web
pages aren't working right. :^)
Specification: https://dom.spec.whatwg.org/#concept-event-dispatch
This also introduces shadow roots due to it being a requirement of
the event dispatcher.
However, it does not introduce the full shadow DOM, that can be
left for future work.
This changes some event dispatches which require certain attributes
to be initialised to a value.
Bring the names of various boxes closer to spec language. This should
hopefully make things easier to understand and hack on. :^)
Some notable changes:
- LayoutNode -> Layout::Node
- LayoutBox -> Layout::Box
- LayoutBlock -> Layout::BlockBox
- LayoutReplaced -> Layout::ReplacedBox
- LayoutDocument -> Layout::InitialContainingBlockBox
- LayoutText -> Layout::TextNode
- LayoutInline -> Layout::InlineNode
Note that this is not strictly a "box tree" as we also hang inline/text
nodes in the same tree, and they don't generate boxes. (Instead, they
contribute line box fragments to their containing block!)
This is a first (huge) step towards modernizing the layout architecture
and bringing it closer to spec language.
Layout is now performed by a stack of formatting contexts, operating on
the box tree (or layout tree, if you will.)
There are currently three types of formatting context:
- BlockFormattingContext (BFC)
- InlineFormattingContext (IFC)
- TableFormattingContext (TFC)
Document::layout() creates the initial BlockFormattingContext (BFC)
which lays out the initial containing block (ICB), and then we recurse
through the tree, creating BFC, IFC or TFC as appropriate and handing
over control at the context boundaries.
The majority of this patch is just refactoring the old logic spread out
in LayoutBlock and LayoutTableRowGroup, and turning into these context
classes instead. A lot more cleanup will be needed.
There are many architectural wins here, the main one being that layout
is no longer performed by boxes themselves, which gives us much greater
flexibility in the outer/inner layout of a given box.
As per this line in the specification:
Unless stated otherwise, a document’s encoding is the utf-8 encoding,
content type is "application/xml", URL is "about:blank", origin is an
opaque origin, type is "xml", and its mode is "no-quirks".
https://dom.spec.whatwg.org/#document
This patch makes Page weakable and allows page-less frames to exist.
Page is single-owner, and Frame is multiple-owner, so it's not sound
for Frame to assume its containing Page will stick around for its own
entire lifetime.
Fixes#3976.
This makes most operations thread safe, especially so that they
can safely be used in the Kernel. This includes obtaining a strong
reference from a weak reference, which now requires an explicit
call to WeakPtr::strong_ref(). Another major change is that
Weakable::make_weak_ref() may require the explicit target type.
Previously we used reinterpret_cast in WeakPtr, assuming that it
can be properly converted. But WeakPtr does not necessarily have
the knowledge to be able to do this. Instead, we now ask the class
itself to deliver a WeakPtr to the type that we want.
Also, WeakLink is no longer specific to a target type. The reason
for this is that we want to be able to safely convert e.g. WeakPtr<T>
to WeakPtr<U>, and before this we just reinterpret_cast the internal
WeakLink<T> to WeakLink<U>, which is a bold assumption that it would
actually produce the correct code. Instead, WeakLink now operates
on just a raw pointer and we only make those constructors/operators
available if we can verify that it can be safely cast.
In order to guarantee thread safety, we now use the least significant
bit in the pointer for locking purposes. This also means that only
properly aligned pointers can be used.
`DOM::XMLHttpRequest` now checks if the requested URL has the same
`Origin` as the requesting `Document`. If the requested URL is in
violation of SOP the request is rejected and an "error" `DOM::Event`
is dispatched.
Ref-counted objects must not be stack allocated. Make DOM::Document's
constructor private to avoid this issue. (I wish we could mark classes
as heap-only..)
When a document reaches ref_count==0, we will now remove all of the
descendant nodes from the document, and also break all the explicit
links (such as the currently hovered element.)
Basically, DOM nodes will keep the document alive even after the
document reaches ref_count==0. This allows JS wrappers to stay alive
and keep the document alive as well. This matches the behavior of
at least some other browsers.
This patch also adds a bunch of sanity checking assertions around
DOM teardown, to help catch mistakes in the future.
Fixes#3771.
DOM::Node now points to its LayoutNode with a WeakPtr.
LayoutNode points to its DOM::Node and DOM::Document with RefPtrs.
Layout trees come and go in response to various events, so the DOM tree
already has to deal with that. The DOM should always live at least as
long as the layout tree, so this patch enforces that assumption by
making layout nodes keep their corresponding DOM objects alive.
This may not be optimal, but it removes a lot of ambiguous raw pointer
action which is not worth accomodating.
Oops, it seems like I implemented all of the "nodes keep the document
alive" mechanism except the part where the functions are actually
called. :^)
Fixes#3811.
Instead of just ripping out the root of the layout tree from its RefPtr
in Document, actually go through the DOM and gather up all the layout
nodes. Then destroy them all in one swoop.
Also, make sure to do this when detaching Document from Frame,
to enforce the invariant that layout only occurs in framed documents.
These happen right after "DOMContentLoaded" for now, which is incorrect
since they should really wait until subresources have loaded.
However, this makes a bunch of things work already so let's do it.
We were never wrapping and using the actual DOM::Event but instead
wrapped the *target* twice and passed it to the event listener callback,
as this value and as argument.
This unbreaks "fun demo" and "canvas path quadratic curve test" - and
event dispatching in general, of course :^)
Fixes#3721.
In addition to being reference-counted, all nodes that are part of a
document must also keep the document alive.
This is achieved by adding a second ref-count to the Document object
and incrementing/decrementing it whenever a node is created/destroyed
in that document.
This brings us much closer to a proper DOM lifetime model, although
the JS bindings still need more work.
