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Make LineSplitter.split not use sync*.

Browse source 
Since dart2wasm doesn't support `sync*` yet,
this removes the only use of `sync*` in the *platform libraries*,
which should make things a little easier.

Change-Id: I9f2936b503ab488b85b869bb4e20de1ff47ca4c0
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/267700
Commit-Queue: Aske Simon Christensen <askesc@google.com>
Reviewed-by: Aske Simon Christensen <askesc@google.com>
This commit is contained in:
Lasse R.H. Nielsen 2022-11-18 15:34:22 +00:00 committed by Commit Queue
parent 65c29efee8
commit 70b88ca80d
1 changed files with 53 additions and 19 deletions
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72
sdk/lib/convert/line_splitter.dart
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@ -44,26 +44,9 @@ class LineSplitter extends StreamTransformerBase<String, String> {
/// `lines.substring(start, end)`. The [start] and [end] values must
/// specify a valid sub-range of [lines]
/// (`0 <= start <= end <= lines.length`).
static Iterable<String> split(String lines, [int start = 0, int? end]) sync* {
static Iterable<String> split(String lines, [int start = 0, int? end]) {
end = RangeError.checkValidRange(start, end, lines.length);
var sliceStart = start;
var char = 0;
for (var i = start; i < end; i++) {
var previousChar = char;
char = lines.codeUnitAt(i);
if (char != _CR) {
if (char != _LF) continue;
if (previousChar == _CR) {
sliceStart = i + 1;
continue;
}
}
yield lines.substring(sliceStart, i);
sliceStart = i + 1;
}
if (sliceStart < end) {
yield lines.substring(sliceStart, end);
}
return _LineSplitIterable(lines, start, end);
}
List<String> convert(String data) {
@ -190,3 +173,54 @@ class _LineSplitterEventSink extends _LineSplitterSink
_eventSink.addError(o, stackTrace);
}
}
class _LineSplitIterable extends Iterable<String> {
final String _source;
final int _start, _end;
_LineSplitIterable(this._source, this._start, this._end);
Iterator<String> get iterator => _LineSplitIterator(_source, _start, _end);
}
class _LineSplitIterator implements Iterator<String> {
final String _source;
final int _end;
int _start;
int _lineStart = 0;
int _lineEnd = -1;
String? _current;
_LineSplitIterator(this._source, this._start, this._end);
bool moveNext() {
_current = null;
_lineStart = _start;
_lineEnd = -1;
var eolLength = 1;
for (var i = _start; i < _end; i++) {
var char = _source.codeUnitAt(i);
if (char != _CR) {
if (char != _LF) continue;
} else {
// Check for CR+LF
if (i + 1 < _end && _source.codeUnitAt(i + 1) == _LF) {
eolLength = 2;
}
}
_lineEnd = i;
_start = i + eolLength;
return true;
}
if (_start < _end) {
_lineEnd = _end;
_start = _end;
return true;
}
_start = _end;
return false;
}
// Creates string lazily on first request.
// Makes it cheaper to do `LineSplitter.split(input).skip(5)...`.
String get current => _current ??= (_lineEnd >= 0
? _source.substring(_lineStart, _lineEnd)
: (throw StateError("No element")));
}