open-nomad/helper/pointer/pointer.go
2023-04-10 15:36:59 +00:00

50 lines
1.1 KiB
Go

// Copyright (c) HashiCorp, Inc.
// SPDX-License-Identifier: MPL-2.0
// Package pointer provides helper functions related to Go pointers.
package pointer
import (
"golang.org/x/exp/constraints"
)
// Primitive represents basic types that are safe to do basic comparisons by
// pointer dereference (checking nullity first).
type Primitive interface {
constraints.Ordered | bool
}
// Of returns a pointer to a.
func Of[A any](a A) *A {
return &a
}
// Copy returns a new pointer to a.
func Copy[A any](a *A) *A {
if a == nil {
return nil
}
na := *a
return &na
}
// Merge will return Copy(next) if next is not nil, otherwise return Copy(previous).
func Merge[P Primitive](previous, next *P) *P {
if next != nil {
return Copy(next)
}
return Copy(previous)
}
// Eq returns whether a and b are equal in underlying value.
//
// May only be used on pointers to primitive types, where the comparison is
// guaranteed to be sensible. For complex types (i.e. structs) consider implementing
// an Equal method.
func Eq[P Primitive](a, b *P) bool {
if a == nil || b == nil {
return a == b
}
return *a == *b
}