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Serializer should cache results from runtimeType.toString() #637
Description
Since runtimeType.toString() may be slow, we should cache the mapping back to the base type for use later. (To be confirmed by benchmarks, of course).
Activity
mkustermann commentedon Apr 25, 2022
@davidmorgan Do you think this optimization could be implemented? We seem to see this on profiles, especially app startup.
mkustermann commentedon Apr 25, 2022
Slightly orthogonal to this issue: Would it be possible to avoid relying on string representation of runtime types (which we don't really promise anything about - e.g. obfuscation may change them)? There seems to be support for an explicit
wireName- could it be enforced to use such names always instead of leaning on runtime types?davidmorgan commentedon Apr 25, 2022
Yes, it should be possible to do this soon; I'm going to be migrating the generator to null safety, it will be convenient to make other small changes at the same time.
Re: the slightly orthogonal issue ;)
Obfuscation doesn't matter as long as it's stable over one run of the VM. The only other property we need is that if there is a
<in the result then stripping off everything up to that point gives you a way to identify the base type without generics.As far as I know this is the only fast way today to map a generic type back to the base type at runtime, e.g. to notice that a
Foo<int>is aFooand aBar<int>is aBar. The alternative is a sequence ofischecks which does not scale well. We need this because anyFoo<X>must be dispatched to theFooserializer. I would be happy to replace with something better if we can find something that works for VM, Flutter and Web :)Thanks.
mkustermann commentedon Apr 25, 2022
👍 for looking into this!
If all objects that can be serialized have common base classes / interfaces they implement, would something like this be feasible:
?
Then the cost would be one method call that returns a constant. This constant can then be used as keys in maps, etc. No need to go via intermediate Strings. (or instead of
Type get rawType => FoouseString get rawTypeAsString => "Foo")davidmorgan commentedon Apr 25, 2022
Unfortunately there's no common base class.
That would have problems of its own: for example, primitives don't implement it, so you can't refer to all serializable types statically.
It's really something that needs just a liiiitle bit of language support ;)
davidmorgan commentedon Apr 26, 2022
Here's a PR: #1132
@mkustermann do you have any handy benchmark we can check it with please? I always like to check performance improvements actually work ;)
mkustermann commentedon Apr 26, 2022
@davidmorgan will forward some information offline.