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[core] Improve JSON decoding performance

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Avoid polymorphic character access by turning _ChunkedJsonParser
into a mixin instead of the base class.

TEST=ci

Change-Id: Id2080724e07d16e96734a80629c8bd8906dc590b
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/358445
Reviewed-by: Daco Harkes <dacoharkes@google.com>
Commit-Queue: Slava Egorov <vegorov@google.com>
This commit is contained in:
Vyacheslav Egorov 2024-03-21 11:10:10 +00:00 committed by Commit Queue
parent 867610409a
commit df80cf9140
1 changed files with 33 additions and 14 deletions
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47
sdk/lib/_internal/vm/lib/convert_patch.dart
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@ -59,9 +59,7 @@ class _JsonUtf8Decoder extends Converter<List<int>, Object?> {
Object? convert(List<int> input) {
var parser = _JsonUtf8DecoderSink._createParser(_reviver, _allowMalformed);
parser.chunk = input;
parser.chunkEnd = input.length;
parser.parse(0);
parser.parseChunk(input, 0, input.length);
parser.close();
return parser.result;
}
@ -249,6 +247,11 @@ class _NumberBuffer {
double parseDouble() => double.parse(getString());
}
abstract class _JsonParserWithListener {
final _JsonListener listener;
_JsonParserWithListener(this.listener);
}
/**
* Chunked JSON parser.
*
@ -256,8 +259,13 @@ class _NumberBuffer {
* and stores input state between chunks.
*
* Implementations include [String] and UTF-8 parsers.
*
* Note: this is a mixin instead of the base class to allow compilers
* to specialize applications otherwise accessing chunk characters becomes
* polymorphic.
*
*/
abstract class _ChunkedJsonParser<T> {
mixin _ChunkedJsonParser<T> on _JsonParserWithListener {
// A simple non-recursive state-based parser for JSON.
//
// Literal values accepted in states ARRAY_EMPTY, ARRAY_COMMA, OBJECT_COLON
@ -388,8 +396,6 @@ abstract class _ChunkedJsonParser<T> {
// Mask used to mask off two lower bits.
static const int TWO_BIT_MASK = 3;
final _JsonListener listener;
// The current parsing state.
int state = STATE_INITIAL;
List<int> states = <int>[];
@ -440,8 +446,6 @@ abstract class _ChunkedJsonParser<T> {
*/
dynamic buffer = null;
_ChunkedJsonParser(this.listener);
/**
* Push the current parse [state] on a stack.
*
@ -1380,7 +1384,8 @@ abstract class _ChunkedJsonParser<T> {
/**
* Chunked JSON parser that parses [String] chunks.
*/
class _JsonStringParser extends _ChunkedJsonParser<String> {
class _JsonStringParser extends _JsonParserWithListener
with _ChunkedJsonParser<String> {
String chunk = '';
int chunkEnd = 0;
@ -1477,11 +1482,12 @@ class _JsonStringDecoderSink extends StringConversionSinkBase {
/**
* Chunked JSON parser that parses UTF-8 chunks.
*/
class _JsonUtf8Parser extends _ChunkedJsonParser<List<int>> {
class _JsonUtf8Parser extends _JsonParserWithListener
with _ChunkedJsonParser<Uint8List> {
static final Uint8List emptyChunk = Uint8List(0);
final _Utf8Decoder decoder;
List<int> chunk = emptyChunk;
Uint8List chunk = emptyChunk;
int chunkEnd = 0;
_JsonUtf8Parser(_JsonListener listener, bool allowMalformed)
@ -1492,6 +1498,21 @@ class _JsonUtf8Parser extends _ChunkedJsonParser<List<int>> {
_ChunkedJsonParser.PARTIAL_KEYWORD | _ChunkedJsonParser.KWD_BOM;
}
void parseChunk(List<int> value, int start, int end) {
if (value is Uint8List) {
chunk = value;
} else {
final bytes = Uint8List(end - start);
bytes.setRange(0, bytes.length, value, start);
end = bytes.length;
start = 0;
chunk = bytes;
}
chunkEnd = end;
parse(start);
}
@pragma('vm:prefer-inline')
int getChar(int position) => chunk[position];
String getString(int start, int end, int bits) {
@ -1569,9 +1590,7 @@ class _JsonUtf8DecoderSink extends ByteConversionSink {
}
void _addChunk(List<int> chunk, int start, int end) {
_parser.chunk = chunk;
_parser.chunkEnd = end;
_parser.parse(start);
_parser.parseChunk(chunk, start, end);
}
void close() {