This commit adds support for the most bare bones version of async
functions, support for async generator functions, async arrow functions
and await expressions are TODO.
The position is added to manually in the line terminator and Unicode
character cases. While it checks for EOF after doing so, the EOF check
used `!=` instead of `<`, meaning if the position went _over_ the
source length, it wouldn't think it was EOF and would cause read buffer
overflows.
For example, `0xea` followed by `0xfd` would cause this.
By using the FlyString(StringView) constructor instead of the
FlyString(String) one, we can dodge a temporary String construction.
This improves parsing time on a large chunk of JS by ~1.6%.
Before this change, Lexer::is_identifier_{start,middle}() would do a
Unicode property lookup via Unicode::code_point_has_property() quite
frequently, especially for common characters like .,;{}[]() etc.
Since these and any other ASCII characters not covered by the alpha /
alphanumeric check are known to not have the ID_Start / ID_Continue
(except '_', which is special-cased now) properties, we can easily
avoid this function call.
When we save/load state in the parser, we preserve the lexer state by
simply making a copy of it. This was made extremely heavy by the lexer
keeping a cache of all parsed identifiers.
It keeps the cache to ensure that StringViews into parsed Unicode escape
sequences don't become dangling views when the Token goes out of scope.
This patch solves the problem by replacing the Vector<FlyString> which
was used to cache the identifiers with a ref-counted
HashTable<FlyString> instead.
Since the purpose of the cache is just to keep FlyStrings alive, it's
fine for all Lexer instances to share the cache. And as a bonus, using a
HashTable instead of a Vector replaces the O(n) accesses with O(1) ones.
This makes a 1.9 MiB JavaScript file parse in 0.6s instead of 24s. :^)
This bug was discovered via OSS fuzz, it's possible to fall through
to this assert with a char_size == 1, so we need to account for that
in the VERIFY(..).
Repro test case can be found in the OSS fuzz bug:
https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=37296
Added a test to ensure the behavior stays the same.
We now throw on a direct usage of an escaped keywords with a specific
error to make it more clear to the user.
For example, "property.br\u{64}wn" should resolve to "property.brown".
To support this behavior, this commit changes the Token class to hold
both the evaluated identifier name and a view into the original source
for the unevaluated name. There are some contexts in which identifiers
are not allowed to contain Unicode escape sequences; for example, export
statements of the form "export {} from foo.js" forbid escapes in the
identifier "from".
The test file is added to .prettierignore because prettier will replace
all escaped Unicode sequences with their unescaped value.
If we consumed whitespace and/or comments after a RegexLiteral token,
the following token must not be RegexFlags - no whitespace or comments
are allowed between the closing / and the flag characters.
Fixes#8201.
Stage 3 since August 2019 - we already have shebang stripping
implemented in js(1), so this removes it from there in favor of adding
support to the lexer directly.
Most straightforward proposal and implementation I've ever seen :^)
https://github.com/tc39/proposal-hashbang
Some of the code assumed that chars were always signed while that is
not the case on ARM hosts.
Also, some of the code tried to use EOF (-1) in a way similar to what
fgetc() does, however instead of storing the characters in an int
variable a char was used.
While this seemed to work it also meant that character 0xFF would be
incorrectly seen as an end-of-file.
Careful reading of fgetc() reveals that fgetc() stores character
data in an int where valid characters are in the range of 0-255 and
the EOF value is explicitly outside of that range (usually -1).
SPDX License Identifiers are a more compact / standardized
way of representing file license information.
See: https://spdx.dev/resources/use/#identifiers
This was done with the `ambr` search and replace tool.
ambr --no-parent-ignore --key-from-file --rep-from-file key.txt rep.txt *
