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32 lines
1.1 KiB
32 lines
1.1 KiB
package web
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import (
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"reflect"
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)
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/*
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This is more than a little sketchtacular. Go's rules for function pointer
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equality are pretty restrictive: nil function pointers always compare equal, and
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all other pointer types never do. However, this is pretty limiting: it means
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that we can't let people reference the middleware they've given us since we have
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no idea which function they're referring to.
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To get better data out of Go, we sketch on the representation of interfaces. We
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happen to know that interfaces are pairs of pointers: one to the real data, one
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to data about the type. Therefore, two interfaces, including two function
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interface{}'s, point to exactly the same objects iff their interface
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representations are identical. And it turns out this is sufficient for our
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purposes.
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If you're curious, you can read more about the representation of functions here:
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http://golang.org/s/go11func
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We're in effect comparing the pointers of the indirect layer.
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This function also works on non-function values.
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*/
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func funcEqual(a, b interface{}) bool {
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av := reflect.ValueOf(&a).Elem()
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bv := reflect.ValueOf(&b).Elem()
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return av.InterfaceData() == bv.InterfaceData()
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}
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