Problem:
- Many constructors are defined as `{}` rather than using the ` =
default` compiler-provided constructor.
- Some types provide an implicit conversion operator from `nullptr_t`
instead of requiring the caller to default construct. This violates
the C++ Core Guidelines suggestion to declare single-argument
constructors explicit
(https://isocpp.github.io/CppCoreGuidelines/CppCoreGuidelines#c46-by-default-declare-single-argument-constructors-explicit).
Solution:
- Change default constructors to use the compiler-provided default
constructor.
- Remove implicit conversion operators from `nullptr_t` and change
usage to enforce type consistency without conversion.
Yay for more spec compliance! This is pretty easy as everything using
to_size_t() should just be using one of the other abstract operations we
already have implemented.
This allows us to get rid of get_length() in ArrayPrototype, which is
basically a slightly incorrect implementation of length_of_array_like(),
and then finally remove to_size_t()!
Also fixes a couple of "argument is undefined" vs "argument isn't given"
issues along the way.
The pseudo-code from the spec says "Assert: Type(obj) is Object.", so we
can just enforce this at compile time rather than taking it literally
and doing "ASSERT(value.is_object())".
Also fix an issue where the absence of a "length" property on the object
would cause a crash (to_number() on empty value).
This adds a String.prototype.split implementation modelled after
ECMA262 specification.
Additionally, `Value::to_u32` was added as an implementation of
the standard `ToUint32` abstract operation.
There is a tiny kludge for when the separator is an empty string.
Basic tests and visiting google.com prove that this is working.
This was missing a "toInt32()" which returns 0 for NaN and Infinity.
From the spec:
6.1.6.1.2 Number::bitwiseNOT ( x )
The abstract operation Number::bitwiseNOT takes argument x (a Number).
It performs the following steps when called:
Let oldValue be ! ToInt32(x).
Return the result of applying bitwise complement to oldValue.
The mathematical value of the result is exactly representable as
a 32-bit two's complement bit string.
Fixes#4868.
When constructing a GlobalObject, it has to pass itself as the global
object to its own Shape. Since this is done in the Object constructor,
and Object is a base class of GlobalObject, it's not yet valid to cast
"this" to a GlobalObject*.
Fix this by having Shape store the global object as an Object& and move
Shape::global_object() to GlobalObject.h where we can at least perform a
valid static_cast in the getter.
Found by oss-fuzz: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=29267
Problem:
- `(void)` simply casts the expression to void. This is understood to
indicate that it is ignored, but this is really a compiler trick to
get the compiler to not generate a warning.
Solution:
- Use the `[[maybe_unused]]` attribute to indicate the value is unused.
Note:
- Functions taking a `(void)` argument list have also been changed to
`()` because this is not needed and shows up in the same grep
command.
This was used for a feature where you could pass a vector of arguments
to enter_scope(). Since that way of passing arguments was not GC-aware
(as vectors use C++ heap storage), let's avoid using it and make sure
everything that needs to stay alive is either on the stack or in traced
storage instead.
We were building up a vector with all the values in an object's indexed
property storage, and then iterating over the vector to mark values.
Instead of this, simply iterate over the property storage directly. :^)
This changes the remaining uses of the following functions across LibJS:
- String::format() => String::formatted()
- dbg() => dbgln()
- printf() => out(), outln()
- fprintf() => warnln()
I also removed the relevant 'LogStream& operator<<' overloads as they're
not needed anymore.
We now lazily create an "arguments" array inside functions when code
tries to access it.
This doesn't follow the spec at all but still covers a lot of the
basic uses of arguments, i.e "arguments.length" and "arguments[n]"
Here's a reasonably faithful implementation of ECMAScript 2021 18.2.5.
Some corner cases are not covered, I've left them as FIXME's in the
included unit test.
Also I had to tweak JS::Value::to_i32() to always convert infinity to
zero, which is in accordance with ToInt32 AFAICT.
This is how the spec describes it, and it allows sharing data between
multiple typed arrays.
Typed arrays now support constructing from an existing ArrayBuffer,
and has been prepared for constructing from another typed array or
iterator as well.
We should pay more attention to using the well-defined abstract
operations from the spec rather than making up our own, often slightly
different rules. This is another step in that direction.
We have multiple array types now, so ArrayInvalidLength has been
replaced with a generic InvalidLength.
Also fixes a small issue in the Array constructor, it should throw
RangeError for invalid lengths, not TypeError.
- Calling without 'new' is an error
- If the first argument is an object, we need a separate code path to
initialize from TypedArray, ArrayBuffer, Iterable or Array-like
object (marked TODO for now)
- Don't insert values into array if more than one argument is present
(that's not part of the spec)
The current implementation is not entirely correct yet. Two classes have
been added:
- TypedArrayConstructor, which the various typed array constructors now
inherit from. Calling or constructing this class (from JS, that is)
directly is not possible, we might want to move this abstract class
functionality to NativeFunction at a later point.
- TypedArrayPrototype, which the various typed array prototypes now have
as their own prototype. This will be the place where most of the
functionality is being shared.
Relevant parts from the spec:
22.2.1 The %TypedArray% Intrinsic Object
The %TypedArray% intrinsic object:
- is a constructor function object that all of the TypedArray
constructor objects inherit from.
- along with its corresponding prototype object, provides common
properties that are inherited by all TypedArray constructors and their
instances.
22.2.2 Properties of the %TypedArray% Intrinsic Object
The %TypedArray% intrinsic object:
- has a [[Prototype]] internal slot whose value is %Function.prototype%.
22.2.2.3 %TypedArray%.prototype
The initial value of %TypedArray%.prototype is the %TypedArray%
prototype object.
22.2.6 Properties of the TypedArray Constructors
Each TypedArray constructor:
- has a [[Prototype]] internal slot whose value is %TypedArray%.
22.2.6.2 TypedArray.prototype
The initial value of TypedArray.prototype is the corresponding
TypedArray prototype intrinsic object (22.2.7).
22.2.7 Properties of the TypedArray Prototype Objects
Each TypedArray prototype object:
- has a [[Prototype]] internal slot whose value is %TypedArray.prototype%.
22.2.7.2 TypedArray.prototype.constructor
The initial value of a TypedArray.prototype.constructor is the
corresponding %TypedArray% intrinsic object.
This patch adds six of the standard type arrays and tries to share as
much code as possible:
- Uint8Array
- Uint16Array
- Uint32Array
- Int8Array
- Int16Array
- Int32Array
