chore: update to go1.21rc2, drop support for go1.19

common/utils/string_unsafe.go

@@ -2,48 +2,20 @@ package utils
 
 import "unsafe"
 
-// sliceHeader is equivalent to reflect.SliceHeader, but represents the pointer
-// to the underlying array as unsafe.Pointer rather than uintptr, allowing
-// sliceHeaders to be directly converted to slice objects.
-type sliceHeader struct {
-	Data unsafe.Pointer
-	Len  int
-	Cap  int
-}
-
-// slice returns a slice whose underlying array starts at ptr an which length
-// and capacity are len.
-func slice[T any](ptr *T, length int) []T {
-	var s []T
-	hdr := (*sliceHeader)(unsafe.Pointer(&s))
-	hdr.Data = unsafe.Pointer(ptr)
-	hdr.Len = length
-	hdr.Cap = length
-	return s
-}
-
-// stringHeader is equivalent to reflect.StringHeader, but represents the
-// pointer to the underlying array as unsafe.Pointer rather than uintptr,
-// allowing StringHeaders to be directly converted to strings.
-type stringHeader struct {
-	Data unsafe.Pointer
-	Len  int
-}
-
 // ImmutableBytesFromString is equivalent to []byte(s), except that it uses the
 // same memory backing s instead of making a heap-allocated copy. This is only
 // valid if the returned slice is never mutated.
 func ImmutableBytesFromString(s string) []byte {
-	shdr := (*stringHeader)(unsafe.Pointer(&s))
-	return slice((*byte)(shdr.Data), shdr.Len)
+	b := unsafe.StringData(s)
+	return unsafe.Slice(b, len(s))
 }
 
 // StringFromImmutableBytes is equivalent to string(bs), except that it uses
 // the same memory backing bs instead of making a heap-allocated copy. This is
 // only valid if bs is never mutated after StringFromImmutableBytes returns.
 func StringFromImmutableBytes(bs []byte) string {
-	// This is cheaper than messing with StringHeader and SliceHeader, which as
-	// of this writing produces many dead stores of zeroes. Compare
-	// strings.Builder.String().
-	return *(*string)(unsafe.Pointer(&bs))
+	if len(bs) == 0 {
+		return ""
+	}
+	return unsafe.String(&bs[0], len(bs))
 }