1 package danger

     2 

     3 import (

     4 	"reflect"

     5 	"unsafe"

     6 )

     7 

     8 // typeID is used as key in encoder and decoder caches to enable using

     9 // the optimize runtime.mapaccess2_fast64 function instead of the more

    10 // expensive lookup if we were to use reflect.Type as map key.

    11 //

    12 // typeID holds the pointer to the reflect.Type value, which is unique

    13 // in the program.

    14 //

    15 // https://github.com/segmentio/encoding/blob/master/json/codec.go#L59-L61

    16 type TypeID unsafe.Pointer

    17 

    18 func MakeTypeID(t reflect.Type) TypeID {

    19 	// reflect.Type has the fields:

    20 	// typ unsafe.Pointer

    21 	// ptr unsafe.Pointer

    22 	return TypeID((*[2]unsafe.Pointer)(unsafe.Pointer(&t))[1])

    23 }