Assigning to a named child counts its list of the matching children, and
assigning through an empty XMLList counts the chain of targets it climbs,
before either changes the tree. copy(), toXMLString(), normalize(), the
`..` selector and the depth check on insertion hold the stack they keep
for each open level of the tree. Inserting an XMLList, and assigning one
to an item of an XMLList, hold their copy of the list's items.
copy() reads attributes in place, and toXMLString() reads attributes and
namespace declarations in place, instead of copying the lists. copy()
charges the declarations it copies before it copies them. Deleting by
name or assigning an attribute compacts the remaining links in place
instead of building a second list.
toXMLString() holds the set of prefixes a namespace lookup passes, and
picks a new nsN prefix in one pass over the declarations in scope
instead of rescanning them for each candidate.
The parser holds its open elements and their names, the text it gathers,
each tag's attribute values, the sets that check declarations and
attribute names, and its one copy of an element's namespaces, and it
charges the strings of the namespace declarations it makes. The
allowance it holds from the source's length covers the copy a value
takes as it becomes a string.
Comparing XML values, converting them to strings, assigning an XMLList
to an attribute, and reading a name, a qualifier, a namespace URI or
embedded text from a string built by joining strings flatten it with
flat_charged. An attribute name read from a string reserves its copy,
and an element name shares the string.
Docs: docs/target-app-parity.md.
$.line and $.stack counted lines in the run's expanded source. In code
that comes after an #include they gave lines that match no file, and
this included code in a file $.evalFile ran and code a named engine
kept from an earlier run.
Both now map each frame through the run's source maps, as uncaught
errors already were. $.stack writes each frame as name@file:line,
outermost first, with the run's name as the file of a script given as
source. Code that eval or Function compiled keeps the line of the
source they compiled, in [eval]; code whose place a named engine no
longer keeps is at line 0 of [unknown]. The 64-frame limit, [global]
and [anonymous] are unchanged.
Docs: docs/mcp.md, docs/target-app-parity.md.
$.fileName gave the file being run, so a function defined in a file
that #include inserted, in a file $.evalFile ran, or in an earlier run
of a named engine reported the calling file instead of its own.
- vectorcraft_js: HostItem::SiteGetter gives a getter the CallSite
(source tag, line, column) of the code that reads it.
- $.fileName maps that place through the run's source maps, or the
maps a named engine kept, to the file the code is in. It is empty in
code from a script given as source and in kept code whose map was
dropped. Code that eval or Function compiled still gets the file
being run.
Docs: docs/mcp.md, docs/target-app-parity.md.
The namespace list that inScopeNamespaces(), namespace(),
namespaceDeclarations(), the XPath namespace axis, XPath prefixes and
XPath name() collect from a node and its ancestors was built in Rust
buffers the heap limit did not see, so a node with many namespaces in
scope let a script grow past its limit.
The scope now holds the bytes of its list and prefix table until it is
dropped, and namespaceDeclarations() also holds its ancestor table and
the declarations it returns. The queried node stays rooted while the
scope is built, and each declaration is read in place instead of
copying every node's namespace list.
Other copies in the same files are held against the limit too:
- addNamespace(), setNamespace(), setName() and removeNamespace() read
an element's attributes one at a time instead of copying the list,
and removeNamespace() holds its walk stack.
- child(index), comments(), text(), elements(), processingInstructions()
and normalize() on an XMLList hold the copy of its items, and
replace() holds the copy of the children it matched.
- XPath name() holds the units of a prefixed name it builds.
- The XML, XMLList, Namespace and QName constructors, isXMLName(),
attribute(), namespace(), propertyIsEnumerable(), setName(),
setLocalName(), addNamespace(), removeNamespace() and setNamespace()
reserve the bytes of the flat copy of a long (rope) string argument
before they make it, and attribute() reserves the copy of a name
without its leading @.
- QName.prototype.toString() reserves its result before it builds it.
A function an earlier run of a named engine defined was reported without
a line, column or file when it threw in a later run. The realm now gives
each source a tag that stays the same from run to run (Realm::error_tag,
Realm::script_tag), and no two sources share one once the tags run out.
Each named engine keeps the source maps of its runs' scripts, included
files and $.evalFile files, within 8 MiB, dropping the oldest first, and
an error in kept code is reported at that file, line and column. The
report's name and the console line keep the calling run's name. For an
earlier script given as source, file is that run's name.
Docs: docs/mcp.md (Script engines), script.run params text,
docs/target-app-parity.md.
flat_charged and the property-key path now root the rope itself, so a string held only by
native code (a getter's result for ++o.x, a valueOf result, a toString key) still counts
what it holds when the reservation collects. The per-call roots for these cases are removed.
When the flattened copy of a String object's concatenated string would pass the heap limit
before a collection can run, the indexed read walks the rope to the unit instead, taking a
unit of fuel for each node it visits, so no copy is made.
- wrapping a string no longer flattens it, so Object(s).length and new String(s) on a large concatenated string make no copy and cannot collect while a call's operands are off the stack
- reading a String object's character by index, `in` and hasOwnProperty count the flattened copy at the next limit check, and the run ends before the copy when the fuel for it is not left
- unary plus on an object whose valueOf returns a concatenated string, and a property key from toString, keep that string rooted while its copy is reserved
- the unshift comment cites step 6 of section 15.4.4.13
Boxing the string receiver of a non-strict function flattens it, and reserving the copy can
collect. The callee, receiver and arguments are already off the stack at that point, so they
stay in the temporary roots until the frame holds them; before, an argument object could be
freed and its cell reused by the wrapper. new String(value) roots the converted string the
same way, so what the rope holds is still counted while its copy is reserved.
- the relational operators root both strings while flattening them, so the first copy still counts when the second one starts a collection
- join roots its separator for the whole join and each element while it is written, and JSON.stringify roots a string while it writes it
- a String object flattens its string when it is made, with the copy counted, so reading one of its characters copies nothing
xml.xpath(expression[, variables]) evaluates an XPath 1.0 expression
(https://www.w3.org/TR/1999/REC-xpath-19991116/) with the XML value as
the context node and returns the selected nodes as an XMLList, in
document order and without repeats. On an XMLList the expression runs
on each element in turn, and the results are joined.
- All 13 axes and the 27 core functions. id() selects nothing, since
E4X trees carry no DTD data.
- Each property of `variables` binds the variable of its name. A
prefix in a name test resolves through the context element's
in-scope namespaces; `xml` is always bound.
- An expression that breaks the grammar gives a SyntaxError. An
unknown function, a wrong argument count, an unbound prefix or
variable, a result that is not a node-set, and a result that holds
the root or a namespace node give a TypeError.
- The parser and the evaluator keep their state on their own stacks,
so expressions of any depth use no native stack; nesting past
Options::max_depth gives "nesting too deep". Traversal stacks, node
lists, strings and the values that string functions build count
against the heap limit, and every node visited and string read takes
fuel.
Docs: docs/target-app-parity.md (E4X line), crate doc in lib.rs.
The fuel and heap checks for a host evaluator's source were split into a third
before encoding and the rest after, so a source whose whole UTF-16 text did not
fit in the heap could still be encoded and parsed. The whole encoded size is now
reserved before encoding. A source over the source limit is still refused as a
syntax error.
A for each loop read the property's value before evaluating its target,
so a target such as (o.p = 2, t).v, t[(o.p = 3, 'w')] or a bare
@[(o.p = 2, 'k')] stored the value from before the target ran. The
target's object and name are now evaluated first and the value is read
after them (ECMA-357 section 12.3).
Flattening a concatenated string copies its units into a new buffer. The
string built-ins reserve that copy with flat_charged, but several other
paths flattened without it, so a script could build copies the heap limit
never saw:
- the relational operators (`<`, `>`, `<=`, `>=`) on two strings, `==`
between a string and a number, unary `+` and every other ToNumber of a
string, and reading a character by index (`s[0]`)
- a property name made from an object whose toString returns a long
string, and a long string used as a property name, which now reserves
its copy before it is made instead of after
- direct `eval` of a concatenated source
- `JSON.stringify` of a string value and its `space` argument
- `Array.prototype.join`'s separator and each string element it writes
Property names and eval source reserve the copy's heap bytes without
taking fuel.
Direct and indirect eval, Function and host evaluators parsed and compiled
their source before taking any fuel or checking the heap, so a script with a
small fuel limit could make the interpreter parse megabytes of source in a
handful of instructions. Interp::prepare_source now takes one unit of fuel for
each UTF-16 code unit and checks that the source text fits in the heap before
the source is flattened, parsed or compiled. A host evaluator's string takes
the fuel for a third of its bytes before it is encoded, and the rest after.
Limits::fuel and the maxFuel row in docs/mcp.md say so.
With Options::e4x set, an E4X name standing alone (@a, @ns::a, @[expr],
ns::a, *) is now a valid target for =, compound assignment, ++, --,
delete and for/for each loops, as well as a read. The target is the
nearest XML or XMLList value in scope whose [[HasProperty]] accepts the
name (ECMA-357 section 11.1). The name is evaluated once, and the
target resolves before the right-hand side runs.
When no XML value in scope holds the name, a read or write throws a
ReferenceError and creates no child or attribute. A read no longer
falls back to the first XML value in scope, so a filter such as
list.(@id == '1') throws when an item has no @id and no outer XML
value holds one, instead of treating that item as not matching.
An XML declaration at the start of XML or XMLList text was skipped up to
the next "?>" without being read. It is now checked against XML 1.0's
grammar (https://www.w3.org/TR/xml/#NT-XMLDecl): a version of "1." and
digits, then an optional encoding name and an optional standalone "yes"
or "no", in that order, with optional white space before "?>". Any other
declaration gives "SyntaxError: invalid XML declaration", and a character
XML does not allow gives "invalid character in XML text". White space
before the declaration is still accepted.
The parser now takes fuel for the length of the declaration and the
white space before it, element and attribute names, white space in open
and closing tags, and the text it searched when an attribute value, CDATA
section, comment or processing instruction is not closed, or when "]]>"
or "<" stops a text run or attribute value. A long run in any of these
used the same fuel as a short one.
A finally block that break or continue leaves no longer keeps the saved
site of the exception it ran for. A Jump now removes the sites at or
above the stack's length, as a return already does, so a collection
after the stack grows back over that slot does not root and count the
old code.
New tests in crates/js/src/host_tests.rs: an error passed on by a
finally block that collects garbage under a 1 MiB heap is reported at
its throw; the saved site keeps direct eval code live through a
collection; a host abort inside a finally block leaves no saved site;
and break, continue and return out of a finally block drop the site.
A literal makes an extensible object whose properties are writable and
configurable, and an array whose length is writable. toSource wrote a
property defined with writable or configurable false, a sealed, frozen or
non-extensible object or array, and an array with a read-only length as an
ordinary literal, so evaluating the text gave an open value.
toSource now throws a TypeError for each of these, at any depth, as it
already does for getters, hidden properties and other prototypes.
Properties defined with every flag on are written as before.
`inScopeNamespaces()`, `namespaceDeclarations()` and `namespace()` walk
from the node up to its root. The walk cloned each ancestor's whole node,
children and attributes included, to read its namespaces, and charged
fuel only for the namespaces it found, so a deep tree with no declared
namespaces cost no fuel. It now takes one unit of fuel per ancestor,
copies only the namespace list and parent link, and checks prefixes
already seen with a set. `namespaceDeclarations()` compares the node's
declarations with the ancestors' through a map instead of a scan.
- `File.encode` and `Folder.encode` leave `/` unescaped, as the File
object reference lists it among the characters kept
(https://extendscript.docsforadobe.dev/file-system-access/file-object/).
- `exists` is true for a `File` only when the path names something
other than a folder, and for a `Folder` only when it names a folder.
- Fields of the records the app returns are read as own properties, so
a property a script puts on `Object.prototype` does not turn a
successful `open` into a failure.
- `File.encode`, `File.decode`, `File.isEncodingAvailable` and the
`Folder` locations count as file calls and charge the host-call limit.
- On the web the locations are `null` and `File.tempName` names a file
at the root, without asking the platform for a temporary folder.
The saved throw sites of running finally blocks are kept in rising slot
order, so leaving a frame or a block now removes entries from the end of
the list and stops at the first one below the slot. Before, every return
looked at every saved site, so a call made inside many nested finally
blocks took time in proportion to their count.
vectorcraft-js and Check Script took identifier categories from
unicode-general-category 1.1.0, which carries Unicode 16.0, so letters
and marks assigned in Unicode 17.0 (U+088F at the start of a name,
U+1ACF after its first character) were refused. Both lexers now read
general categories from unicode-properties 0.1.4 (Unicode 17.0), which
Cargo.lock already holds. The version is exact because 0.1.5 adds the
Unicode-3.0 license, which is not on the license allowlist. The
Other_ID_Start, Other_ID_Continue and Pattern_Syntax lists are the same
in PropList 17.0.
The exhaustive identifier test now expects the DerivedCoreProperties
17.0 totals (145,916 ID_Start, 149,240 ID_Continue), and new tests read
U+088F and U+1ACF written out and as escapes in both lexers.
Resetting Folder.current for the next run of a named engine now drops the
last run's uncaught exception and $.error first, so memory only they held
no longer makes the reset fail with the heap limit on every later run.
A File an earlier run left open now counts as closed in a later run:
setting its encoding stores it for the next open, and reading the encoding
gives the stored one.
docs/mcp.md: engines stay on the thread that made them, and a
#targetengine line in a file $.evalFile runs makes that call throw a
SyntaxError when it runs.
A `return` inside a finally block discards the pending exception, but the
saved throw site for it stayed in the list of collection roots. The code it
pointed to then stayed live after the function was gone, which could stop a
script with the heap limit when that code came from `Function` or `eval`.
Returning from a frame now drops the saved sites for the slots it leaves.
Follows #6653.
BFlat