custom hashCode/== in Element to speed up inheritFromWidgetOfExactType #13019
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Hixie
reviewed
Nov 15, 2017
| // Custom implementation of `operator ==` optimized for the ".of" pattern | ||
| // used with `InheritedWidgets`. | ||
| @override | ||
| bool operator ==(Object other) => identical(this, other); |
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is that not what the inherited operator == does?
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I believe so, but the linter says if you overload hashCode you must also overload operator==.
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fair enough. i guess this is no worse than an // ignore would be.
Hixie
reviewed
Nov 15, 2017
| // `Set` look-ups, putting this getter on the performance critical path. | ||
| @override | ||
| int get hashCode => _cachedHash; | ||
| final int _cachedHash = _nextHashCode = (_nextHashCode + 1) % 0xffffff; |
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Copied from dart-lang/sdk#31011 (comment), but I'm guessing this is so it fits within the SMI representation.
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Adding a comment with explanation.
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We're about to switch to 64bit ints, which might make this moot.
cc @floitschG for advice.
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DaveShuckerow
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May 14, 2018
flutter#13019) * custom hashCode/== in Element to speed up inheritFromWidgetOfExactType * explain why 24 bits
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See dart-lang/sdk#31011
WARNING: There's an ongoing regression introduced by #12933