* Refuse to serialize some combinations of values that the shorthand
can not represent: 'grid-template-areas: (not none)' combined with
'grid-template-rows: subgrid' or 'grid-template-columns: subgrid'.
(The former used to cause an assertion failure.)
* Remove an extraneous trailing space that occured when a <track-list>
was last. (ie. followed by an omitted <line-names>)
* Add tests for the result of this serialization.
This adds CSS parser error reporting for parsing of custom properties
and normal properties that have variable references.
When re-parsing a normal property that had a variable reference, we
report any parse error to be at the beginning of the property value.
This is because it is difficult to keep track of where exactly each
variable substitution came from to point to the particular value
that would have caused the parse error. For example, with this:
:root {
var-a: 1px 2px;
var-b: 3px var(a);
}
p {
margin: var(a) var(b);
}
we would end up resolving the value of 'margin' to:
" 1px 2px 3px 1px 2px"
In this string, the parse error occurs when we encounter the final
"2px", but by this point we don't know where that value came from.
So instead we just point to the line on which 'margin' was declared.
We extend ErrorReporter with an OutputError overload that takes the
specific line and column number to use in the error report to get this
right, and we store the line and column number for each token stream
we parse on the nsCSSValueTokenStream object.
This adds a new eCSSUnit_SharedList type for nsCSSValue, which is a
reference counted object that contains an nsCSSValueList. We need this
so that nsStyleDisplay::mSpecifiedTransform can hold a strong reference
to a specified transform list value. When 'transform' is specified
using a variable reference, the resulting nsCSSValue does not stick
around in the Declaration object, so we wouldn't be guaranteed that
it lives long enough for nsStyleDisplay to keep referencing it.
Patch co-authored by Emmanuele Bassi <ebassi@gmail.com>
This adds a new nsCSSValue unit type to represent an unparsed
stream of CSS tokens as a specified value. This is what properties
that have a variable reference get as their specified value.
On the nsCSSValueTokenStream object that is used when mUnit ==
eCSSUnit_TokenStream, we store two property IDs: first, the property
ID for the longhand that this token stream value is the value for. We
pass this back in to nsCSSParser::ParseProperty at computed value time,
when we need to re-parse the property. Second is the shorthand property
ID, if we used a variable reference in a shorthand. In such a case, we
store the token stream value for each of the corresponding longhand
properties. This is because shorthands don't actually get any storage
in an nsRuleData, and because any of the longhands might be overwritten
by subsequent declarations, we need to keep the token stream somewhere.
We also store other information on the nsCSSValueTokenStream required by
the CSS parser (base URI, etc.).
As filed the bug is about table backgrounds failing to print. The root cause of this is that we load images from the original document, because print/print-preview documents (which are static clones of the original) cannot do loads. This results in an entry in the css::ImageValue's request table under the original document, but entry under the printing document. Then we do layout, try to get the request, and fail, and nothing is displayed. The solution to this is to force us to clone the request for the printing document if we're loading off the original document. I manually verified that this does not regress Bug 560235.
While writing a test for this, we discovered another problem. The reftest print code does not actually use the printing codepath. Instead it takes an existing document, tears down its presshell, and creates a new presshell for printing. Fixing the above bug did not make the reftest print test pass because ImageLoader does not deal properly with presshell destruction/recreation. It assumes that when the presshell is destroyed all of the css::ImageValues can be cleared of their entries for that document. This fails for ImageValues for mapped attributes because they are held alive by the content tree. When a new presshell for this document is then created there is no entry for the document and thus no image request to paint. The fix for this is to only clear the frame to request and request to frame mapping hashtables and not to clear the document's entry on the ImageValue when the presshell is destroyed. The destruction of the ImageLoader (which is held from a strong reference on the document) is when those entries are removed. The final change is to change css::ImageValue's hashtable from holding a strong reference to the keys (which are documents) to holding raw pointer references. This is safe because we clear the relevant entry when the corresponding ImageLoader dies, and is needed to prevent a reference cycle that was being broken by presshell destruction.
