Currently, when we need to repeat an instruction N times, we simply add
that instruction N times in a for-loop. This doesn't scale well with
extremely large values of N, and ECMA-262 allows up to N = 2^53 - 1.
Instead, add a new REPEAT bytecode operation to defer this loop from the
parser to the runtime executor. This allows the parser to complete sans
any loops (for this instruction), and allows the executor to bail early
if the repeated bytecode fails.
Note: The templated ByteCode methods are to allow the Posix parsers to
continue using u32 because they are limited to N = 2^20.
Combining these into one list helps reduce the size of MatchState, and
as a result, reduces the amount of memory consumed during execution of
very large regex matches.
Doing this also allows us to remove a few regex byte code instructions:
ClearNamedCaptureGroup, SaveLeftNamedCaptureGroup, and NamedReference.
Named groups now behave the same as unnamed groups for these operations.
Note that SaveRightNamedCaptureGroup still exists to cache the matched
group name.
This also removes the recursion level from the MatchState, as it can
exist as a local variable in Matcher::execute instead.
The grammar for the ECMA-262 CharacterEscape is:
CharacterEscape[U, N] ::
ControlEscape
c ControlLetter
0 [lookahead ∉ DecimalDigit]
HexEscapeSequence
RegExpUnicodeEscapeSequence[?U]
[~U]LegacyOctalEscapeSequence
IdentityEscape[?U, ?N]
It's important to parse the standalone "\0 [lookahead ∉ DecimalDigit]"
before parsing LegacyOctalEscapeSequence. Otherwise, all standalone "\0"
patterns are parsed as octal, which are disallowed in Unicode mode.
Further, LegacyOctalEscapeSequence should also be parsed while parsing
character classes.
A subsequent commit will add tests that require a string containing only
"\0". As a C-string, this will be interpreted as the null terminator. To
make the diff for that commit easier to grok, this commit converts all
tests to use StringView without any other functional changes.
* Only alphabetic (A-Z, a-z) characters may be escaped with \c. The loop
currently parsing \c includes code points between the upper/lower case
groups.
* In Unicode mode, all invalid identity escapes should cause a parser
error, even in browser-extended mode.
* Avoid an infinite loop when parsing the pattern "\c" on its own.
Similarly to the LibCpp parser regression tests, these tests run the
preprocessor on the .cpp test files under
Userland/LibCpp/Tests/preprocessor, and compare the output with existing
.txt ground truth files.
These script extensions have some peculiar behavior in the Unicode spec.
The UCD ScriptExtension file does not contain these scripts. Rather, it
is implied the code points which have these scripts as an extension are
the code points that both:
1. Have Common or Inherited as their primary script value
2. Do not have any other script value in their script extension lists
Because these are not explictly listed in the UCD, we must manually form
these script extensions.
Notice that unlike the note in populate_general_category_unions(),
script extension do indeed have code point ranges which overlap. Thus,
this commit adds code to handle that, and hooks it into the GC unions.
Previously, each code point's General Category was part of the generated
UnicodeData structure. This ultimately presented two problems, one
functional and one performance related:
* Some General Categories are applied to unassigned code points, for
example the Unassigned (Cn) category. Unassigned code points are
strictly excluded from UnicodeData.txt, so by relying on that file,
the generator is unable to handle these categories.
* Lookups for General Categories are slower when searching through the
large UnicodeData hash map. Even though lookups are O(1), the hash
function turned out to be slower than binary searching through a
category-specific table.
So, now a table is generated for each General Category. When querying a
code point for a category, a binary search is done on each code point
range in that category's table to check if code point has that category.
Further, General Categories are now parsed from the UCD file
DerivedGeneralCategory.txt. This file is a normal "prop list" file and
contains the categories for unassigned code points.
There seems to be more incorrect assumptions about Clang-built
executables' memory layout than expected. These make the CI fail even
though the system is functional in all other aspects. While this is
being fixed, let's just disable tests for UserspaceEmulator.
This helps us avoid weird truncation issues and fixes a bug on Clang
builds where truncation while reading caused the DIE offsets following
large LEB128 numbers to be incorrect. This removes the need for the
separate `LongUnsignedNumber` type.
We now call Preprocessor::process_and_lex() and pass the result to the
parser.
Doing the lexing in the preprocessor will allow us to maintain the
original position information of tokens after substituting definitions.
Improve the parsing of data urls in URLParser to bring it more up-to-
spec. At the moment, we cannot parse the components of the MIME type
since it is represented as a string, but the spec requires it to be
parsed as a "MIME type record".
This is a regression test to validate the functionality that was
reported broken in #9071, where the kernel would spin attempting
to cancel a stale timer.
Before now, only binary properties could be parsed. Non-binary props are
of the form "Type=Value", where "Type" may be General_Category, Script,
or Script_Extension (or their aliases). Of these, LibUnicode currently
supports General_Category, so LibRegex can parse only that type.
This changes LibRegex to parse the property escape as a Variant of
Unicode Property & General Category values. A byte code instruction is
added to perform matching based on General Category values.
The following commit broke Tests/AK/TestJSON.cpp as it removed the
file that the test loaded from disk to validate JSON parsing.
commit ad141a2286
Author: Andreas Kling <kling@serenityos.org>
Date: Sat Jul 31 15:26:14 2021 +0200
Base: Remove "test.frm" from HackStudio test project
Instead of restoring the file, lets just embed a bit of JSON in the
test case to avoid using external resources, as they obviously are
surprising and make the test less portable across environments.
This supports some binary property matching. It does not support any
properties not yet parsed by LibUnicode, nor does it support value
matching (such as Script_Extensions=Latin).
Previously unmapping any offset starting at 0x0 would assert in the
kernel, add a regression test to validate the fix.
Co-authored-by: Federico Guerinoni <guerinoni.federico@gmail.com>
Apparently, some code points fit both categories, for example U+0345
(COMBINING GREEK YPOGEGRAMMENI). Handle this fact when determining if
a code point is a final code point in a string.
This implements unconditional special case folding, and conditional
folding for non-locale cases. Worth noting that the only conditional,
non-locale special case is for converting an uppercase sigma to
lowercase.
The Unicode standard publishes the Unicode Character Database (UCD) with
information about every code point, such as each code point's upper case
mapping. LibUnicode exists to download and parse UCD files at build time
and to provide accessors to that data.
As a start, LibUnicode includes upper- and lower-case code point
converters.
Previously there was no way to create a MACAddress by passing a direct
address as a string. This will allow programs like the arp utility to
create a MACAddress instance by user-passed addresses.
