src/objects/string.tq

// Copyright 2019 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

@abstract
@generateCppClass
@reserveBitsInInstanceType(6)
extern class String extends Name {
  length: int32;
}

@generateCppClass
extern class ConsString extends String {
  first: String;
  second: String;
}

@abstract
extern class ExternalString extends String {
  resource: RawPtr;
  resource_data: RawPtr;
}

extern class ExternalOneByteString extends ExternalString {}
extern class ExternalTwoByteString extends ExternalString {}

@generateCppClass
extern class InternalizedString extends String {
}

// TODO(v8:8983): Add declaration for variable-sized region.
@abstract
@generateCppClass
extern class SeqString extends String {
}
@generateCppClass
extern class SeqOneByteString extends SeqString {
  chars[length]: char8;
}
@generateCppClass
extern class SeqTwoByteString extends SeqString {
  chars[length]: char16;
}

@generateCppClass
extern class SlicedString extends String {
  parent: String;
  offset: Smi;
}

@generateCppClass
extern class ThinString extends String {
  actual: String;
}

// A direct string can be accessed directly through CSA without going into the
// C++ runtime. See also: ToDirectStringAssembler.
type DirectString extends String;

@export
macro AllocateSeqOneByteString(length: uint32): String {
  assert(length <= kStringMaxLength);
  if (length == 0) return kEmptyString;
  return new SeqOneByteString{
    map: kOneByteStringMap,
    hash_field: kNameEmptyHashField,
    length: Signed(length),
    chars: ...UninitializedIterator {}
  };
}

@export
macro AllocateSeqTwoByteString(length: uint32): String {
  assert(length <= kStringMaxLength);
  if (length == 0) return kEmptyString;
  return new SeqTwoByteString{
    map: kStringMap,
    hash_field: kNameEmptyHashField,
    length: Signed(length),
    chars: ...UninitializedIterator {}
  };
}