Skip to content

Commit

Permalink
Normative: Align detached buffer semantics with web reality (#2164)
Browse files Browse the repository at this point in the history
  • Loading branch information
@rkirsling @ljharb
rkirsling authored and ljharb committed Oct 15, 2020
1 parent b1afdde commit a4a142c
Showing 1 changed file with 56 additions and 38 deletions.
94 changes: 56 additions & 38 deletions spec.html
View file
Original file line number Diff line number Diff line change
Expand Up @@ -9139,7 +9139,7 @@ <h1>MakeArgSetter ( _name_, _env_ )</h1>
<h1>Integer-Indexed Exotic Objects</h1>
<p>An Integer-Indexed exotic object is an exotic object that performs special handling of integer index property keys.</p>
<p><emu-xref href="#integer-indexed-exotic-object">Integer-Indexed exotic objects</emu-xref> have the same internal slots as ordinary objects and additionally [[ViewedArrayBuffer]], [[ArrayLength]], [[ByteOffset]], [[ContentType]], and [[TypedArrayName]] internal slots.</p>
<p>An object is an <dfn id="integer-indexed-exotic-object">Integer-Indexed exotic object</dfn> if its [[GetOwnProperty]], [[HasProperty]], [[DefineOwnProperty]], [[Get]], [[Set]], and [[OwnPropertyKeys]] internal methods use the definitions in this section, and its other essential internal methods use the definitions found in <emu-xref href="#sec-ordinary-object-internal-methods-and-internal-slots"></emu-xref>. These methods are installed by IntegerIndexedObjectCreate.</p>
<p>An object is an <dfn id="integer-indexed-exotic-object">Integer-Indexed exotic object</dfn> if its [[GetOwnProperty]], [[HasProperty]], [[DefineOwnProperty]], [[Get]], [[Set]], [[Delete]], and [[OwnPropertyKeys]] internal methods use the definitions in this section, and its other essential internal methods use the definitions found in <emu-xref href="#sec-ordinary-object-internal-methods-and-internal-slots"></emu-xref>. These methods are installed by IntegerIndexedObjectCreate.</p>

<emu-clause id="sec-integer-indexed-exotic-objects-getownproperty-p">
<h1>[[GetOwnProperty]] ( _P_ )</h1>
Expand All @@ -9150,9 +9150,9 @@ <h1>[[GetOwnProperty]] ( _P_ )</h1>
1. If Type(_P_) is String, then
1. Let _numericIndex_ be ! CanonicalNumericIndexString(_P_).
1. If _numericIndex_ is not *undefined*, then
1. Let _value_ be ? IntegerIndexedElementGet(_O_, _numericIndex_).
1. Let _value_ be ! IntegerIndexedElementGet(_O_, _numericIndex_).
1. If _value_ is *undefined*, return *undefined*.
1. Return the PropertyDescriptor { [[Value]]: _value_, [[Writable]]: *true*, [[Enumerable]]: *true*, [[Configurable]]: *false* }.
1. Return the PropertyDescriptor { [[Value]]: _value_, [[Writable]]: *true*, [[Enumerable]]: *true*, [[Configurable]]: *true* }.
1. Return OrdinaryGetOwnProperty(_O_, _P_).
</emu-alg>
</emu-clause>
Expand All @@ -9167,7 +9167,7 @@ <h1>[[HasProperty]] ( _P_ )</h1>
1. Let _numericIndex_ be ! CanonicalNumericIndexString(_P_).
1. If _numericIndex_ is not *undefined*, then
1. Let _buffer_ be _O_.[[ViewedArrayBuffer]].
1. If IsDetachedBuffer(_buffer_) is *true*, throw a *TypeError* exception.
1. If IsDetachedBuffer(_buffer_) is *true*, return *false*.
1. If ! IsValidIntegerIndex(_O_, _numericIndex_) is *false*, return *false*.
1. Return *true*.
1. Return ? OrdinaryHasProperty(_O_, _P_).
Expand All @@ -9185,7 +9185,7 @@ <h1>[[DefineOwnProperty]] ( _P_, _Desc_ )</h1>
1. If _numericIndex_ is not *undefined*, then
1. If ! IsValidIntegerIndex(_O_, _numericIndex_) is *false*, return *false*.
1. If IsAccessorDescriptor(_Desc_) is *true*, return *false*.
1. If _Desc_ has a [[Configurable]] field and if _Desc_.[[Configurable]] is *true*, return *false*.
1. If _Desc_ has a [[Configurable]] field and if _Desc_.[[Configurable]] is *false*, return *false*.
1. If _Desc_ has an [[Enumerable]] field and if _Desc_.[[Enumerable]] is *false*, return *false*.
1. If _Desc_ has a [[Writable]] field and if _Desc_.[[Writable]] is *false*, return *false*.
1. If _Desc_ has a [[Value]] field, then
Expand All @@ -9204,7 +9204,7 @@ <h1>[[Get]] ( _P_, _Receiver_ )</h1>
1. If Type(_P_) is String, then
1. Let _numericIndex_ be ! CanonicalNumericIndexString(_P_).
1. If _numericIndex_ is not *undefined*, then
1. Return ? IntegerIndexedElementGet(_O_, _numericIndex_).
1. Return ! IntegerIndexedElementGet(_O_, _numericIndex_).
1. Return ? OrdinaryGet(_O_, _P_, _Receiver_).
</emu-alg>
</emu-clause>
Expand All @@ -9222,6 +9222,22 @@ <h1>[[Set]] ( _P_, _V_, _Receiver_ )</h1>
</emu-alg>
</emu-clause>

<emu-clause id="sec-integer-indexed-exotic-objects-delete-p">
<h1>[[Delete]] ( _P_ )</h1>
<p>When the [[Delete]] internal method of an Integer-Indexed exotic object _O_ is called with property key _P_, the following steps are taken:</p>
<emu-alg>
1. Assert: IsPropertyKey(_P_) is *true*.
1. Assert: _O_ is an Integer-Indexed exotic object.
1. If Type(_P_) is String, then
1. Let _numericIndex_ be ! CanonicalNumericIndexString(_P_).
1. If _numericIndex_ is not *undefined*, then
1. If IsDetachedBuffer(_O_.[[ViewedArrayBuffer]]) is *true*, return *true*.
1. If ! IsValidIntegerIndex(_O_, _numericIndex_) is *false*, return *true*.
1. Return *false*.
1. Return ? OrdinaryDelete(_O_, _P_).
</emu-alg>
</emu-clause>

<emu-clause id="sec-integer-indexed-exotic-objects-ownpropertykeys">
<h1>[[OwnPropertyKeys]] ( )</h1>
<p>When the [[OwnPropertyKeys]] internal method of an Integer-Indexed exotic object _O_ is called, the following steps are taken:</p>
Expand Down Expand Up @@ -9250,6 +9266,7 @@ <h1>IntegerIndexedObjectCreate ( _prototype_ )</h1>
1. Set _A_.[[DefineOwnProperty]] as specified in <emu-xref href="#sec-integer-indexed-exotic-objects-defineownproperty-p-desc"></emu-xref>.
1. Set _A_.[[Get]] as specified in <emu-xref href="#sec-integer-indexed-exotic-objects-get-p-receiver"></emu-xref>.
1. Set _A_.[[Set]] as specified in <emu-xref href="#sec-integer-indexed-exotic-objects-set-p-v-receiver"></emu-xref>.
1. Set _A_.[[Delete]] as specified in <emu-xref href="#sec-integer-indexed-exotic-objects-delete-p"></emu-xref>.
1. Set _A_.[[OwnPropertyKeys]] as specified in <emu-xref href="#sec-integer-indexed-exotic-objects-ownpropertykeys"></emu-xref>.
1. Set _A_.[[Prototype]] to _prototype_.
1. Return _A_.
Expand All @@ -9274,7 +9291,7 @@ <h1>IntegerIndexedElementGet ( _O_, _index_ )</h1>
<emu-alg>
1. Assert: _O_ is an Integer-Indexed exotic object.
1. Let _buffer_ be _O_.[[ViewedArrayBuffer]].
1. If IsDetachedBuffer(_buffer_) is *true*, throw a *TypeError* exception.
1. If IsDetachedBuffer(_buffer_) is *true*, return *undefined*.
1. If ! IsValidIntegerIndex(_O_, _index_) is *false*, return *undefined*.
1. Let _offset_ be _O_.[[ByteOffset]].
1. Let _arrayTypeName_ be the String value of _O_.[[TypedArrayName]].
Expand All @@ -9293,7 +9310,7 @@ <h1>IntegerIndexedElementSet ( _O_, _index_, _value_ )</h1>
1. If _O_.[[ContentType]] is ~BigInt~, let _numValue_ be ? ToBigInt(_value_).
1. Otherwise, let _numValue_ be ? ToNumber(_value_).
1. Let _buffer_ be _O_.[[ViewedArrayBuffer]].
1. If IsDetachedBuffer(_buffer_) is *true*, throw a *TypeError* exception.
1. If IsDetachedBuffer(_buffer_) is *true*, return *false*.
1. If ! IsValidIntegerIndex(_O_, _index_) is *false*, return *false*.
1. Let _offset_ be _O_.[[ByteOffset]].
1. Let _arrayTypeName_ be the String value of _O_.[[TypedArrayName]].
Expand Down Expand Up @@ -34610,7 +34627,7 @@ <h1>%TypedArray%.prototype.filter ( _callbackfn_ [ , _thisArg_ ] )</h1>
1. Let _captured_ be 0.
1. Repeat, while _k_ &lt; _len_,
1. Let _Pk_ be ! ToString(𝔽(_k_)).
1. Let _kValue_ be ? Get(_O_, _Pk_).
1. Let _kValue_ be ! Get(_O_, _Pk_).
1. Let _selected_ be ! ToBoolean(? Call(_callbackfn_, _thisArg_, &laquo; _kValue_, 𝔽(_k_), _O_ &raquo;)).
1. If _selected_ is *true*, then
1. Append _kValue_ to the end of _kept_.
Expand Down Expand Up @@ -34706,7 +34723,7 @@ <h1>%TypedArray%.prototype.map ( _callbackfn_ [ , _thisArg_ ] )</h1>
1. Let _k_ be 0.
1. Repeat, while _k_ &lt; _len_,
1. Let _Pk_ be ! ToString(𝔽(_k_)).
1. Let _kValue_ be ? Get(_O_, _Pk_).
1. Let _kValue_ be ! Get(_O_, _Pk_).
1. Let _mappedValue_ be ? Call(_callbackfn_, _thisArg_, &laquo; _kValue_, 𝔽(_k_), _O_ &raquo;).
1. Perform ? Set(_A_, _Pk_, _mappedValue_, *true*).
1. Set _k_ to _k_ + 1.
Expand Down Expand Up @@ -34849,33 +34866,34 @@ <h1>%TypedArray%.prototype.slice ( _start_, _end_ )</h1>
1. Else, let _final_ be min(_relativeEnd_, _len_).
1. Let _count_ be max(_final_ - _k_, 0).
1. Let _A_ be ? TypedArraySpeciesCreate(_O_, &laquo; 𝔽(_count_) &raquo;).
1. Let _srcName_ be the String value of _O_.[[TypedArrayName]].
1. Let _srcType_ be the Element Type value in <emu-xref href="#table-the-typedarray-constructors"></emu-xref> for _srcName_.
1. Let _targetName_ be the String value of _A_.[[TypedArrayName]].
1. Let _targetType_ be the Element Type value in <emu-xref href="#table-the-typedarray-constructors"></emu-xref> for _targetName_.
1. If _srcType_ is different from _targetType_, then
1. Let _n_ be 0.
1. Repeat, while _k_ &lt; _final_,
1. Let _Pk_ be ! ToString(𝔽(_k_)).
1. Let _kValue_ be ? Get(_O_, _Pk_).
1. Perform ! Set(_A_, ! ToString(𝔽(_n_)), _kValue_, *true*).
1. Set _k_ to _k_ + 1.
1. Set _n_ to _n_ + 1.
1. Else if _count_ &gt; 0, then
1. Let _srcBuffer_ be _O_.[[ViewedArrayBuffer]].
1. If IsDetachedBuffer(_srcBuffer_) is *true*, throw a *TypeError* exception.
1. Let _targetBuffer_ be _A_.[[ViewedArrayBuffer]].
1. Let _elementSize_ be the Element Size value specified in <emu-xref href="#table-the-typedarray-constructors"></emu-xref> for Element Type _srcType_.
1. NOTE: If _srcType_ and _targetType_ are the same, the transfer must be performed in a manner that preserves the bit-level encoding of the source data.
1. Let _srcByteOffet_ be _O_.[[ByteOffset]].
1. Let _targetByteIndex_ be _A_.[[ByteOffset]].
1. Let _srcByteIndex_ be (_k_ &times; _elementSize_) + _srcByteOffet_.
1. Let _limit_ be _targetByteIndex_ + _count_ &times; _elementSize_.
1. Repeat, while _targetByteIndex_ &lt; _limit_,
1. Let _value_ be GetValueFromBuffer(_srcBuffer_, _srcByteIndex_, ~Uint8~, *true*, ~Unordered~).
1. Perform SetValueInBuffer(_targetBuffer_, _targetByteIndex_, ~Uint8~, _value_, *true*, ~Unordered~).
1. Set _srcByteIndex_ to _srcByteIndex_ + 1.
1. Set _targetByteIndex_ to _targetByteIndex_ + 1.
1. If _count_ &gt; 0, then
1. If IsDetachedBuffer(_O_.[[ViewedArrayBuffer]]) is *true*, throw a *TypeError* exception.
1. Let _srcName_ be the String value of _O_.[[TypedArrayName]].
1. Let _srcType_ be the Element Type value in <emu-xref href="#table-the-typedarray-constructors"></emu-xref> for _srcName_.
1. Let _targetName_ be the String value of _A_.[[TypedArrayName]].
1. Let _targetType_ be the Element Type value in <emu-xref href="#table-the-typedarray-constructors"></emu-xref> for _targetName_.
1. If _srcType_ is different from _targetType_, then
1. Let _n_ be 0.
1. Repeat, while _k_ &lt; _final_,
1. Let _Pk_ be ! ToString(𝔽(_k_)).
1. Let _kValue_ be ! Get(_O_, _Pk_).
1. Perform ! Set(_A_, ! ToString(𝔽(_n_)), _kValue_, *true*).
1. Set _k_ to _k_ + 1.
1. Set _n_ to _n_ + 1.
1. Else,
1. Let _srcBuffer_ be _O_.[[ViewedArrayBuffer]].
1. Let _targetBuffer_ be _A_.[[ViewedArrayBuffer]].
1. Let _elementSize_ be the Element Size value specified in <emu-xref href="#table-the-typedarray-constructors"></emu-xref> for Element Type _srcType_.
1. NOTE: If _srcType_ and _targetType_ are the same, the transfer must be performed in a manner that preserves the bit-level encoding of the source data.
1. Let _srcByteOffset_ be _O_.[[ByteOffset]].
1. Let _targetByteIndex_ be _A_.[[ByteOffset]].
1. Let _srcByteIndex_ be (_k_ &times; _elementSize_) + _srcByteOffset_.
1. Let _limit_ be _targetByteIndex_ + _count_ &times; _elementSize_.
1. Repeat, while _targetByteIndex_ &lt; _limit_,
1. Let _value_ be GetValueFromBuffer(_srcBuffer_, _srcByteIndex_, ~Uint8~, *true*, ~Unordered~).
1. Perform SetValueInBuffer(_targetBuffer_, _targetByteIndex_, ~Uint8~, _value_, *true*, ~Unordered~).
1. Set _srcByteIndex_ to _srcByteIndex_ + 1.
1. Set _targetByteIndex_ to _targetByteIndex_ + 1.
1. Return _A_.
</emu-alg>
<p>This function is not generic. The *this* value must be an object with a [[TypedArrayName]] internal slot.</p>
Expand Down Expand Up @@ -36573,7 +36591,7 @@ <h1>get ArrayBuffer.prototype.byteLength</h1>
1. Let _O_ be the *this* value.
1. Perform ? RequireInternalSlot(_O_, [[ArrayBufferData]]).
1. If IsSharedArrayBuffer(_O_) is *true*, throw a *TypeError* exception.
1. If IsDetachedBuffer(_O_) is *true*, throw a *TypeError* exception.
1. If IsDetachedBuffer(_O_) is *true*, return *+0*<sub>𝔽</sub>.
1. Let _length_ be _O_.[[ArrayBufferByteLength]].
1. Return 𝔽(_length_).
</emu-alg>
Expand Down

0 comments on commit a4a142c

Please sign in to comment.