Update dependencies

vendor/tailscale.com/util/deephash/pointer.go

@@ -0,0 +1,114 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+package deephash
+
+import (
+	"net/netip"
+	"reflect"
+	"time"
+	"unsafe"
+)
+
+// unsafePointer is an untyped pointer.
+// It is the caller's responsibility to call operations on the correct type.
+//
+// This pointer only ever points to a small set of kinds or types:
+// time.Time, netip.Addr, string, array, slice, struct, map, pointer, interface,
+// or a pointer to memory that is directly hashable.
+//
+// Arrays are represented as pointers to the first element.
+// Structs are represented as pointers to the first field.
+// Slices are represented as pointers to a slice header.
+// Pointers are represented as pointers to a pointer.
+//
+// We do not support direct operations on maps and interfaces, and instead
+// rely on pointer.asValue to convert the pointer back to a reflect.Value.
+// Conversion of an unsafe.Pointer to reflect.Value guarantees that the
+// read-only flag in the reflect.Value is unpopulated, avoiding panics that may
+// otherwise have occurred since the value was obtained from an unexported field.
+type unsafePointer struct{ p unsafe.Pointer }
+
+func unsafePointerOf(v reflect.Value) unsafePointer {
+	return unsafePointer{v.UnsafePointer()}
+}
+func (p unsafePointer) isNil() bool {
+	return p.p == nil
+}
+
+// pointerElem dereferences a pointer.
+// p must point to a pointer.
+func (p unsafePointer) pointerElem() unsafePointer {
+	return unsafePointer{*(*unsafe.Pointer)(p.p)}
+}
+
+// sliceLen returns the slice length.
+// p must point to a slice.
+func (p unsafePointer) sliceLen() int {
+	return (*reflect.SliceHeader)(p.p).Len
+}
+
+// sliceArray returns a pointer to the underlying slice array.
+// p must point to a slice.
+func (p unsafePointer) sliceArray() unsafePointer {
+	return unsafePointer{unsafe.Pointer((*reflect.SliceHeader)(p.p).Data)}
+}
+
+// arrayIndex returns a pointer to an element in the array.
+// p must point to an array.
+func (p unsafePointer) arrayIndex(index int, size uintptr) unsafePointer {
+	return unsafePointer{unsafe.Add(p.p, uintptr(index)*size)}
+}
+
+// structField returns a pointer to a field in a struct.
+// p must pointer to a struct.
+func (p unsafePointer) structField(index int, offset, size uintptr) unsafePointer {
+	return unsafePointer{unsafe.Add(p.p, offset)}
+}
+
+// asString casts p as a *string.
+func (p unsafePointer) asString() *string {
+	return (*string)(p.p)
+}
+
+// asTime casts p as a *time.Time.
+func (p unsafePointer) asTime() *time.Time {
+	return (*time.Time)(p.p)
+}
+
+// asAddr casts p as a *netip.Addr.
+func (p unsafePointer) asAddr() *netip.Addr {
+	return (*netip.Addr)(p.p)
+}
+
+// asValue casts p as a reflect.Value containing a pointer to value of t.
+func (p unsafePointer) asValue(typ reflect.Type) reflect.Value {
+	return reflect.NewAt(typ, p.p)
+}
+
+// asMemory returns the memory pointer at by p for a specified size.
+func (p unsafePointer) asMemory(size uintptr) []byte {
+	return unsafe.Slice((*byte)(p.p), size)
+}
+
+// visitStack is a stack of pointers visited.
+// Pointers are pushed onto the stack when visited, and popped when leaving.
+// The integer value is the depth at which the pointer was visited.
+// The length of this stack should be zero after every hashing operation.
+type visitStack map[unsafe.Pointer]int
+
+func (v visitStack) seen(p unsafe.Pointer) (int, bool) {
+	idx, ok := v[p]
+	return idx, ok
+}
+
+func (v *visitStack) push(p unsafe.Pointer) {
+	if *v == nil {
+		*v = make(map[unsafe.Pointer]int)
+	}
+	(*v)[p] = len(*v)
+}
+
+func (v visitStack) pop(p unsafe.Pointer) {
+	delete(v, p)
+}