Correctness improvements:
* UTF errors are handled safely per spec instead of dangerously truncating
strings.
* There are fewer converter implementations.
Performance improvements:
* The old code did exact buffer length math, which meant doing UTF math twice
on each input string (once for length calculation and another time for
conversion). Exact length math is more complicated when handling errors
properly, which the old code didn't do. The new code does UTF math on the
string content only once (when converting) but risks allocating more than
once. There are heuristics in place to lower the probability of
reallocation in cases where the double math avoidance isn't enough of a
saving to absorb an allocation and memcpy.
* Previously, in UTF-16 <-> UTF-8 conversions, an ASCII prefix was optimized
but a single non-ASCII code point pessimized the rest of the string. The
new code tries to get back on the fast ASCII path.
* UTF-16 to Latin1 conversion guarantees less about handling of out-of-range
input to eliminate an operation from the inner loop on x86/x86_64.
* When assigning to a pre-existing string, the new code tries to reuse the
old buffer instead of first releasing the old buffer and then allocating a
new one.
* When reallocating from the new code, the memcpy covers only the data that
is part of the logical length of the old string instead of memcpying the
whole capacity. (For old callers old excess memcpy behavior is preserved
due to bogus callers. See bug 1472113.)
* UTF-8 strings in XPConnect that are in the Latin1 range are passed to
SpiderMonkey as Latin1.
New features:
* Conversion between UTF-8 and Latin1 is added in order to enable faster
future interop between Rust code (or otherwise UTF-8-using code) and text
node and SpiderMonkey code that uses Latin1.
MozReview-Commit-ID: JaJuExfILM9
This patch is an automatic replacement of s/NS_NOTREACHED/MOZ_ASSERT_UNREACHABLE/. Reindenting long lines and whitespace fixups follow in patch 6b.
MozReview-Commit-ID: 5UQVHElSpCr
--HG--
extra : rebase_source : 4c1b2fc32b269342f07639266b64941e2270e9c4
extra : source : 907543f6eae716f23a6de52b1ffb1c82908d158a
This was done automatically replacing:
s/mozilla::Move/std::move/
s/ Move(/ std::move(/
s/(Move(/(std::move(/
Removing the 'using mozilla::Move;' lines.
And then with a few manual fixups, see the bug for the split series..
MozReview-Commit-ID: Jxze3adipUh
This rearranges how synthetic-bold use is determined in the font selection
& rendering code. Previously, we would decide during the font-selection
algorithm whether we need to apply synthetic-bold to the chosen face, and
then pass that decision through the fontgroup (storing it in the FamilyFace
entries of the mFonts array there) down to the actual rendering code that
instantiates fonts from the faces (font entries) we've selected.
That became a problem for variation fonts because in the case of a user
font, we may not have downloaded the resource yet, so we just have a "user
font container" entry, which carries the descriptors from the @font-face
rule and will fetch the actual resource when needed. But in the case of a
@font-face rule without a weight descriptor, we don't actually know at
font-selection time whether the face will support "true" bold (via a
variation axis) or not, so we can't reliably make the right decision about
applying synthetic bold.
So we now defer that decision until we actually instantiate a platform font
object to shape/measure/draw text. At that point, we have the requested
style and we also have the real font resource, so we can easily determine
whether fake-bold is required.
(This patch should not result in any visible behavior change; that will
come in a second patch now that the architecture supports it.)
This avoids a redundant alloc and copy in `PutBuffer`. All existing callers
were destroying the passed in buffer after the call.
--HG--
extra : rebase_source : 065505219d70d26bad49c7eba2cec8edf0e9939d
extra : amend_source : 118eddad4dc901da02817c788fb98f6f4c85a3f0
extra : source : 7f0cedfb4bd85bfe1a523168019864c9c6c0e665
