Improve the performance of isCircularProxy#1866
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The map implementation used by `MapMaker` is fairly old and requires 2 levels of indirection (segments->table). Switching to `ConcurrentHashMap` would be better but this will still be redundant with logic inside of `Proxy` so instead we just use that. Based on some simple benchmarks this is about 5X as fast, and should save a bit memory. A number of alternatives were considered * adding a marker interface to the list of proxy interfaces This is a completely ideal solution but fails due to our need to support proxying interfaces from all `ClassLoaders` and it isn't possible to proxy interfaces that cannot mutually 'see' each other. So we would need to 'inject' our interface into the Bootstrap classloader which seems impossible and risky, or create special 'child' classloaders that can bridge it, but this triggers issues with proxying package-private interfaces... sigh. * using a `ClassValue`, bootstrapping the value is tricky and while this is faster than the status quo, it would allocate an entry for every class we queried which could add up in a large application, and the approach in this change is faster. * using `Proxy.isProxyInstance` this works but is slower than an `instanceof` query. PiperOrigin-RevId: 721984180
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Improve the performance of
isCircularProxyThe map implementation used by
MapMakeris fairly old and requires 2 levels of indirection (segments->table). Switching toConcurrentHashMapwould be better but this will still be redundant with logic inside ofProxyso instead we just use that. Based on some simple benchmarks this is about 5X as fast, and should save a bit memory.A number of alternatives were considered
This is a completely ideal solution but fails due to our need to support proxying interfaces from all
ClassLoadersand it isn't possible to proxy interfaces that cannot mutually 'see' each other. So we would need to 'inject' our interface into the Bootstrap classloader which seems impossible and risky, or create special 'child' classloaders that can bridge it, but this triggers issues with proxying package-private interfaces... sigh.ClassValue, bootstrapping the value is tricky and while this is faster than the status quo, it would allocate an entry for every class we queried which could add up in a large application, and the approach in this change is faster.Proxy.isProxyInstancethis works but is slower than aninstanceofquery.