This implements the bulk of the FontFace JS constructor, which parses
the descriptors passed in. We need a notion now of whether a FontFace is
"initialized", since the spec requires us to go through the event loop
before parsing the 'src' descriptor. So a couple of places now have to
check whether the FontFace is fully initialized, and we have a method to
inform the FontFaceSet when a FontFace becomes initialized, in case we
added it to the FontFaceSet before it was initialized (easy to do with
|document.fonts.add(new FontFace(...))|.
This adds support for a CSS-connected FontFace to be disconnected from
its rule. This causes it to get its own copy of the descriptors on the
nsCSSFontFaceStyleDecl, and for the pointers between the FontFace and
the nsCSSFontFaceRule to be nulled out.
We start tracking now whether a given FontFace is in the FontFaceSet
(in the sense that it will appear on the DOM FontFaceSet object if we
inspect it with script). All FontFace objects created though, whether
they are currently "in" the FontFaceSet or not, are still tracked by the
FontFaceSet. We use the new mUnavailableFaces array on the FontFaceSet
for that.
We need to track these FontFaces that aren't in the FontFaceSet as
that's where we store their user font entry -- important if we call
load() on a FontFace before adding it to the FontFaceSet.
Here we change FontFaceSet's records array to associate gfxUserFontEntry
pointers with FontFace pointers, rather than with nsCSSFontFaceRule
pointers. This will make it more uniform to handle both CSS-connected
and unconnected FontFace objects when rebuilding the user font entries
under UpdateRules.
These set the descriptors, but don't cause anything to update, just
like setting descriptors on an @font-face rule's style declaration
doesn't do anything yet.
We add an mDescriptors that will be used to store the descriptor values
of an unconnected FontFace object. For CSS-connected FontFace objects,
the descriptors are stored in the nsCSSFontFaceRule::mDecl.mDescriptors.
(Both of these use the same type, though, CSSFontFaceDescriptors.)
Ideally we could have the descriptors always stored on the FontFace,
and for the nsCSSFontFaceStyleDecl go and fetch them from the FontFace,
but it turned out to be impossible to ensure that a FontFace could be
created whenever a nsCSSFontFaceStyleDecl was cloned, since it needs
access to the window object to create the FontFace's promise objects!
We make gfxUserFontEntry::SetLoadState virtual so that we can hook into
changes and update FontFace::mStatus. We can't just reflect the
gfxUserFontEntry's value in FontFace::Status() since the spec has
requirements about when exactly the status is set.
Every nsCSSFontFaceRule that is used will get a FontFace object to
reflect it in the FontFaceSet. Here we add storage on the
nsCSSFontFaceRule for its FontFace, although it will be the
FontFaceSet's responsibility to set it. We also add a static
constructor function on FontFace to create one that reflects a rule.
We can't make FontFace inherit from gfxUserFontEntry, since the former
is cycle collected. So instead, we have a small class that inherits
from it that will override its virtual methods and forward things on to
the FontFace object.
We make gfxUserFontSet::CreateFontFace virtual so we can override it to
produce instances of our gfxUserFontEntry subclass.
