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// Copyright 2014 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.
#include "src/string-builder.h"
#include "src/isolate-inl.h"
#include "src/objects-inl.h"
namespace v8 {
namespace internal {
MaybeHandle<String> ReplacementStringBuilder::ToString() {
Isolate* isolate = heap_->isolate();
if (array_builder_.length() == 0) {
return isolate->factory()->empty_string();
}
Handle<String> joined_string;
if (is_one_byte_) {
Handle<SeqOneByteString> seq;
ASSIGN_RETURN_ON_EXCEPTION(
isolate, seq, isolate->factory()->NewRawOneByteString(character_count_),
String);
DisallowHeapAllocation no_gc;
uint8_t* char_buffer = seq->GetChars();
StringBuilderConcatHelper(*subject_, char_buffer, *array_builder_.array(),
array_builder_.length());
joined_string = Handle<String>::cast(seq);
} else {
// Two-byte.
Handle<SeqTwoByteString> seq;
ASSIGN_RETURN_ON_EXCEPTION(
isolate, seq, isolate->factory()->NewRawTwoByteString(character_count_),
String);
DisallowHeapAllocation no_gc;
uc16* char_buffer = seq->GetChars();
StringBuilderConcatHelper(*subject_, char_buffer, *array_builder_.array(),
array_builder_.length());
joined_string = Handle<String>::cast(seq);
}
return joined_string;
}
IncrementalStringBuilder::IncrementalStringBuilder(Isolate* isolate)
: isolate_(isolate),
encoding_(String::ONE_BYTE_ENCODING),
overflowed_(false),
part_length_(kInitialPartLength),
current_index_(0) {
// Create an accumulator handle starting with the empty string.
accumulator_ =
Handle<String>::New(ReadOnlyRoots(isolate).empty_string(), isolate);
current_part_ =
factory()->NewRawOneByteString(part_length_).ToHandleChecked();
}
void IncrementalStringBuilder::Accumulate(Handle<String> new_part) {
Handle<String> new_accumulator;
if (accumulator()->length() + new_part->length() > String::kMaxLength) {
// Set the flag and carry on. Delay throwing the exception till the end.
new_accumulator = factory()->empty_string();
overflowed_ = true;
} else {
new_accumulator =
factory()->NewConsString(accumulator(), new_part).ToHandleChecked();
}
set_accumulator(new_accumulator);
}
void IncrementalStringBuilder::Extend() {
DCHECK_EQ(current_index_, current_part()->length());
Accumulate(current_part());
if (part_length_ <= kMaxPartLength / kPartLengthGrowthFactor) {
part_length_ *= kPartLengthGrowthFactor;
}
Handle<String> new_part;
if (encoding_ == String::ONE_BYTE_ENCODING) {
new_part = factory()->NewRawOneByteString(part_length_).ToHandleChecked();
} else {
new_part = factory()->NewRawTwoByteString(part_length_).ToHandleChecked();
}
// Reuse the same handle to avoid being invalidated when exiting handle scope.
set_current_part(new_part);
current_index_ = 0;
}
MaybeHandle<String> IncrementalStringBuilder::Finish() {
ShrinkCurrentPart();
Accumulate(current_part());
if (overflowed_) {
THROW_NEW_ERROR(isolate_, NewInvalidStringLengthError(), String);
}
return accumulator();
}
void IncrementalStringBuilder::AppendString(Handle<String> string) {
ShrinkCurrentPart();
part_length_ = kInitialPartLength; // Allocate conservatively.
Extend(); // Attach current part and allocate new part.
Accumulate(string);
}
} // namespace internal
} // namespace v8
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