forked from jshiffer/matterbridge
54 lines
1.5 KiB
Go
54 lines
1.5 KiB
Go
|
// Copyright 2022 The Go Authors. All rights reserved.
|
||
|
|
// Use of this source code is governed by a BSD-style
|
||
|
|
// license that can be found in the LICENSE file.
|
||
|
|
|
||
|
|
//go:build go1.19 && !go1.20
|
||
|
|
|
||
|
|
package slog
|
||
|
|
|
||
|
|
import (
|
||
|
|
"reflect"
|
||
|
|
"unsafe"
|
||
|
|
)
|
||
|
|
|
||
|
|
type (
|
||
|
|
stringptr unsafe.Pointer // used in Value.any when the Value is a string
|
||
|
|
groupptr unsafe.Pointer // used in Value.any when the Value is a []Attr
|
||
|
|
)
|
||
|
|
|
||
|
|
// StringValue returns a new Value for a string.
|
||
|
|
func StringValue(value string) Value {
|
||
|
|
hdr := (*reflect.StringHeader)(unsafe.Pointer(&value))
|
||
|
|
return Value{num: uint64(hdr.Len), any: stringptr(hdr.Data)}
|
||
|
|
}
|
||
|
|
|
||
|
|
func (v Value) str() string {
|
||
|
|
var s string
|
||
|
|
hdr := (*reflect.StringHeader)(unsafe.Pointer(&s))
|
||
|
|
hdr.Data = uintptr(v.any.(stringptr))
|
||
|
|
hdr.Len = int(v.num)
|
||
|
|
return s
|
||
|
|
}
|
||
|
|
|
||
|
|
// String returns Value's value as a string, formatted like fmt.Sprint. Unlike
|
||
|
|
// the methods Int64, Float64, and so on, which panic if v is of the
|
||
|
|
// wrong kind, String never panics.
|
||
|
|
func (v Value) String() string {
|
||
|
|
if sp, ok := v.any.(stringptr); ok {
|
||
|
|
// Inlining this code makes a huge difference.
|
||
|
|
var s string
|
||
|
|
hdr := (*reflect.StringHeader)(unsafe.Pointer(&s))
|
||
|
|
hdr.Data = uintptr(sp)
|
||
|
|
hdr.Len = int(v.num)
|
||
|
|
return s
|
||
|
|
}
|
||
|
|
return string(v.append(nil))
|
||
|
|
}
|
||
|
|
|
||
|
|
// GroupValue returns a new Value for a list of Attrs.
|
||
|
|
// The caller must not subsequently mutate the argument slice.
|
||
|
|
func GroupValue(as ...Attr) Value {
|
||
|
|
hdr := (*reflect.SliceHeader)(unsafe.Pointer(&as))
|
||
|
|
return Value{num: uint64(hdr.Len), any: groupptr(hdr.Data)}
|
||
|
|
}
|