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Fix JSON.stringify's slow path wrt sliced strings.

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R=mvstanton@chromium.org
BUG=229923

Review URL: https://chromiumcodereview.appspot.com/14107004

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@14224 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
This commit is contained in:
yangguo@chromium.org 2013-04-11 09:53:00 +00:00
parent c96a928c75
commit da5c11a44a
2 changed files with 45 additions and 10 deletions
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14
src/json-stringifier.h
View File

@ -295,29 +295,23 @@ MaybeObject* BasicJsonStringifier::StringifyString(Isolate* isolate,
return stringifier.Stringify(object);
}
object = FlattenGetString(object);
FlattenString(object);
ASSERT(object->IsFlat());
if (object->IsOneByteRepresentation()) {
if (object->IsOneByteRepresentationUnderneath()) {
Handle<String> result =
isolate->factory()->NewRawOneByteString(worst_case_length);
AssertNoAllocation no_alloc;
const uint8_t* start = object->IsSeqOneByteString()
? SeqOneByteString::cast(*object)->GetChars()
: ExternalAsciiString::cast(*object)->GetChars();
return StringifyString_<SeqOneByteString>(
isolate,
Vector<const uint8_t>(start, object->length()),
object->GetFlatContent().ToOneByteVector(),
result);
} else {
Handle<String> result =
isolate->factory()->NewRawTwoByteString(worst_case_length);
AssertNoAllocation no_alloc;
const uc16* start = object->IsSeqTwoByteString()
? SeqTwoByteString::cast(*object)->GetChars()
: ExternalTwoByteString::cast(*object)->GetChars();
return StringifyString_<SeqTwoByteString>(
isolate,
Vector<const uc16>(start, object->length()),
object->GetFlatContent().ToUC16Vector(),
result);
}
}

41
test/mjsunit/regress/regress-crbug-229923.js Normal file
View File

@ -0,0 +1,41 @@
// Copyright 2013 the V8 project authors. All rights reserved.
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following
// disclaimer in the documentation and/or other materials provided
// with the distribution.
// * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived
// from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
// Flags: --expose-externalize-string
var slice = "slow path of JSON.stringify for sliced string".substring(1);
assertEquals('"' + slice + '"', JSON.stringify(slice, null, 0));
var parent = "external string turned into two byte";
var slice_of_external = parent.substring(1);
try {
// Turn the string to a two-byte external string, so that the sliced
// string looks like one-byte, but its parent is actually two-byte.
externalizeString(parent, true);
} catch (e) { }
assertEquals('"' + slice_of_external + '"',
JSON.stringify(slice_of_external, null, 0));