Line data    Source code

       1             : // Copyright 2014 the V8 project authors. All rights reserved.
       2             : // Use of this source code is governed by a BSD-style license that can be
       3             : // found in the LICENSE file.
       4             : 
       5             : #include "src/string-builder.h"
       6             : 
       7             : #include "src/isolate-inl.h"
       8             : #include "src/objects-inl.h"
       9             : 
      10             : namespace v8 {
      11             : namespace internal {
      12             : 
      13        8643 : MaybeHandle<String> ReplacementStringBuilder::ToString() {
      14        8643 :   Isolate* isolate = heap_->isolate();
      15       17231 :   if (array_builder_.length() == 0) {
      16          36 :     return isolate->factory()->empty_string();
      17             :   }
      18             : 
      19             :   Handle<String> joined_string;
      20        8607 :   if (is_one_byte_) {
      21             :     Handle<SeqOneByteString> seq;
      22       16960 :     ASSIGN_RETURN_ON_EXCEPTION(
      23             :         isolate, seq, isolate->factory()->NewRawOneByteString(character_count_),
      24             :         String);
      25             : 
      26             :     DisallowHeapAllocation no_gc;
      27        8461 :     uint8_t* char_buffer = seq->GetChars();
      28             :     StringBuilderConcatHelper(*subject_, char_buffer, *array_builder_.array(),
      29        8461 :                               array_builder_.length());
      30             :     joined_string = Handle<String>::cast(seq);
      31             :   } else {
      32             :     // Two-byte.
      33             :     Handle<SeqTwoByteString> seq;
      34         254 :     ASSIGN_RETURN_ON_EXCEPTION(
      35             :         isolate, seq, isolate->factory()->NewRawTwoByteString(character_count_),
      36             :         String);
      37             : 
      38             :     DisallowHeapAllocation no_gc;
      39         127 :     uc16* char_buffer = seq->GetChars();
      40             :     StringBuilderConcatHelper(*subject_, char_buffer, *array_builder_.array(),
      41         127 :                               array_builder_.length());
      42             :     joined_string = Handle<String>::cast(seq);
      43             :   }
      44        8588 :   return joined_string;
      45             : }
      46             : 
      47             : 
      48    17657126 : IncrementalStringBuilder::IncrementalStringBuilder(Isolate* isolate)
      49             :     : isolate_(isolate),
      50             :       encoding_(String::ONE_BYTE_ENCODING),
      51             :       overflowed_(false),
      52             :       part_length_(kInitialPartLength),
      53     8828563 :       current_index_(0) {
      54             :   // Create an accumulator handle starting with the empty string.
      55    17657126 :   accumulator_ = Handle<String>::New(isolate->heap()->empty_string(), isolate);
      56             :   current_part_ =
      57    26485689 :       factory()->NewRawOneByteString(part_length_).ToHandleChecked();
      58     8828563 : }
      59             : 
      60             : 
      61    71924284 : void IncrementalStringBuilder::Accumulate(Handle<String> new_part) {
      62             :   Handle<String> new_accumulator;
      63    35962142 :   if (accumulator()->length() + new_part->length() > String::kMaxLength) {
      64             :     // Set the flag and carry on. Delay throwing the exception till the end.
      65             :     new_accumulator = factory()->empty_string();
      66          50 :     overflowed_ = true;
      67             :   } else {
      68             :     new_accumulator =
      69    71924185 :         factory()->NewConsString(accumulator(), new_part).ToHandleChecked();
      70             :   }
      71             :   set_accumulator(new_accumulator);
      72    35962143 : }
      73             : 
      74             : 
      75    28659246 : void IncrementalStringBuilder::Extend() {
      76             :   DCHECK_EQ(current_index_, current_part()->length());
      77    14329623 :   Accumulate(current_part());
      78    14329623 :   if (part_length_ <= kMaxPartLength / kPartLengthGrowthFactor) {
      79    14158223 :     part_length_ *= kPartLengthGrowthFactor;
      80             :   }
      81             :   Handle<String> new_part;
      82    14329623 :   if (encoding_ == String::ONE_BYTE_ENCODING) {
      83    40729398 :     new_part = factory()->NewRawOneByteString(part_length_).ToHandleChecked();
      84             :   } else {
      85     2259471 :     new_part = factory()->NewRawTwoByteString(part_length_).ToHandleChecked();
      86             :   }
      87             :   // Reuse the same handle to avoid being invalidated when exiting handle scope.
      88             :   set_current_part(new_part);
      89    14329623 :   current_index_ = 0;
      90    14329623 : }
      91             : 
      92             : 
      93     8828023 : MaybeHandle<String> IncrementalStringBuilder::Finish() {
      94     8828023 :   ShrinkCurrentPart();
      95     8828023 :   Accumulate(current_part());
      96     8828023 :   if (overflowed_) {
      97          50 :     THROW_NEW_ERROR(isolate_, NewInvalidStringLengthError(), String);
      98             :   }
      99     8827973 :   return accumulator();
     100             : }
     101             : 
     102             : 
     103    12804497 : void IncrementalStringBuilder::AppendString(Handle<String> string) {
     104    12804497 :   ShrinkCurrentPart();
     105    12804497 :   part_length_ = kInitialPartLength;  // Allocate conservatively.
     106    12804497 :   Extend();  // Attach current part and allocate new part.
     107    12804497 :   Accumulate(string);
     108    12804497 : }
     109             : }  // namespace internal
     110             : }  // namespace v8