1 files changed, 456 insertions, 0 deletions
diff --git a/vendor/golang.org/x/exp/slog/value.go b/vendor/golang.org/x/exp/slog/value.go
new file mode 100644
index 000000000..3550c46fc
--- /dev/null
+++ b/vendor/golang.org/x/exp/slog/value.go
@@ -0,0 +1,456 @@
+// 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.
+
+package slog
+
+import (
+	"fmt"
+	"math"
+	"runtime"
+	"strconv"
+	"strings"
+	"time"
+	"unsafe"
+
+	"golang.org/x/exp/slices"
+)
+
+// A Value can represent any Go value, but unlike type any,
+// it can represent most small values without an allocation.
+// The zero Value corresponds to nil.
+type Value struct {
+	_ [0]func() // disallow ==
+	// num holds the value for Kinds Int64, Uint64, Float64, Bool and Duration,
+	// the string length for KindString, and nanoseconds since the epoch for KindTime.
+	num uint64
+	// If any is of type Kind, then the value is in num as described above.
+	// If any is of type *time.Location, then the Kind is Time and time.Time value
+	// can be constructed from the Unix nanos in num and the location (monotonic time
+	// is not preserved).
+	// If any is of type stringptr, then the Kind is String and the string value
+	// consists of the length in num and the pointer in any.
+	// Otherwise, the Kind is Any and any is the value.
+	// (This implies that Attrs cannot store values of type Kind, *time.Location
+	// or stringptr.)
+	any any
+}
+
+// Kind is the kind of a Value.
+type Kind int
+
+// The following list is sorted alphabetically, but it's also important that
+// KindAny is 0 so that a zero Value represents nil.
+
+const (
+	KindAny Kind = iota
+	KindBool
+	KindDuration
+	KindFloat64
+	KindInt64
+	KindString
+	KindTime
+	KindUint64
+	KindGroup
+	KindLogValuer
+)
+
+var kindStrings = []string{
+	"Any",
+	"Bool",
+	"Duration",
+	"Float64",
+	"Int64",
+	"String",
+	"Time",
+	"Uint64",
+	"Group",
+	"LogValuer",
+}
+
+func (k Kind) String() string {
+	if k >= 0 && int(k) < len(kindStrings) {
+		return kindStrings[k]
+	}
+	return "<unknown slog.Kind>"
+}
+
+// Unexported version of Kind, just so we can store Kinds in Values.
+// (No user-provided value has this type.)
+type kind Kind
+
+// Kind returns v's Kind.
+func (v Value) Kind() Kind {
+	switch x := v.any.(type) {
+	case Kind:
+		return x
+	case stringptr:
+		return KindString
+	case timeLocation:
+		return KindTime
+	case groupptr:
+		return KindGroup
+	case LogValuer:
+		return KindLogValuer
+	case kind: // a kind is just a wrapper for a Kind
+		return KindAny
+	default:
+		return KindAny
+	}
+}
+
+//////////////// Constructors
+
+// IntValue returns a Value for an int.
+func IntValue(v int) Value {
+	return Int64Value(int64(v))
+}
+
+// Int64Value returns a Value for an int64.
+func Int64Value(v int64) Value {
+	return Value{num: uint64(v), any: KindInt64}
+}
+
+// Uint64Value returns a Value for a uint64.
+func Uint64Value(v uint64) Value {
+	return Value{num: v, any: KindUint64}
+}
+
+// Float64Value returns a Value for a floating-point number.
+func Float64Value(v float64) Value {
+	return Value{num: math.Float64bits(v), any: KindFloat64}
+}
+
+// BoolValue returns a Value for a bool.
+func BoolValue(v bool) Value {
+	u := uint64(0)
+	if v {
+		u = 1
+	}
+	return Value{num: u, any: KindBool}
+}
+
+// Unexported version of *time.Location, just so we can store *time.Locations in
+// Values. (No user-provided value has this type.)
+type timeLocation *time.Location
+
+// TimeValue returns a Value for a time.Time.
+// It discards the monotonic portion.
+func TimeValue(v time.Time) Value {
+	if v.IsZero() {
+		// UnixNano on the zero time is undefined, so represent the zero time
+		// with a nil *time.Location instead. time.Time.Location method never
+		// returns nil, so a Value with any == timeLocation(nil) cannot be
+		// mistaken for any other Value, time.Time or otherwise.
+		return Value{any: timeLocation(nil)}
+	}
+	return Value{num: uint64(v.UnixNano()), any: timeLocation(v.Location())}
+}
+
+// DurationValue returns a Value for a time.Duration.
+func DurationValue(v time.Duration) Value {
+	return Value{num: uint64(v.Nanoseconds()), any: KindDuration}
+}
+
+// AnyValue returns a Value for the supplied value.
+//
+// If the supplied value is of type Value, it is returned
+// unmodified.
+//
+// Given a value of one of Go's predeclared string, bool, or
+// (non-complex) numeric types, AnyValue returns a Value of kind
+// String, Bool, Uint64, Int64, or Float64. The width of the
+// original numeric type is not preserved.
+//
+// Given a time.Time or time.Duration value, AnyValue returns a Value of kind
+// KindTime or KindDuration. The monotonic time is not preserved.
+//
+// For nil, or values of all other types, including named types whose
+// underlying type is numeric, AnyValue returns a value of kind KindAny.
+func AnyValue(v any) Value {
+	switch v := v.(type) {
+	case string:
+		return StringValue(v)
+	case int:
+		return Int64Value(int64(v))
+	case uint:
+		return Uint64Value(uint64(v))
+	case int64:
+		return Int64Value(v)
+	case uint64:
+		return Uint64Value(v)
+	case bool:
+		return BoolValue(v)
+	case time.Duration:
+		return DurationValue(v)
+	case time.Time:
+		return TimeValue(v)
+	case uint8:
+		return Uint64Value(uint64(v))
+	case uint16:
+		return Uint64Value(uint64(v))
+	case uint32:
+		return Uint64Value(uint64(v))
+	case uintptr:
+		return Uint64Value(uint64(v))
+	case int8:
+		return Int64Value(int64(v))
+	case int16:
+		return Int64Value(int64(v))
+	case int32:
+		return Int64Value(int64(v))
+	case float64:
+		return Float64Value(v)
+	case float32:
+		return Float64Value(float64(v))
+	case []Attr:
+		return GroupValue(v...)
+	case Kind:
+		return Value{any: kind(v)}
+	case Value:
+		return v
+	default:
+		return Value{any: v}
+	}
+}
+
+//////////////// Accessors
+
+// Any returns v's value as an any.
+func (v Value) Any() any {
+	switch v.Kind() {
+	case KindAny:
+		if k, ok := v.any.(kind); ok {
+			return Kind(k)
+		}
+		return v.any
+	case KindLogValuer:
+		return v.any
+	case KindGroup:
+		return v.group()
+	case KindInt64:
+		return int64(v.num)
+	case KindUint64:
+		return v.num
+	case KindFloat64:
+		return v.float()
+	case KindString:
+		return v.str()
+	case KindBool:
+		return v.bool()
+	case KindDuration:
+		return v.duration()
+	case KindTime:
+		return v.time()
+	default:
+		panic(fmt.Sprintf("bad kind: %s", v.Kind()))
+	}
+}
+
+// Int64 returns v's value as an int64. It panics
+// if v is not a signed integer.
+func (v Value) Int64() int64 {
+	if g, w := v.Kind(), KindInt64; g != w {
+		panic(fmt.Sprintf("Value kind is %s, not %s", g, w))
+	}
+	return int64(v.num)
+}
+
+// Uint64 returns v's value as a uint64. It panics
+// if v is not an unsigned integer.
+func (v Value) Uint64() uint64 {
+	if g, w := v.Kind(), KindUint64; g != w {
+		panic(fmt.Sprintf("Value kind is %s, not %s", g, w))
+	}
+	return v.num
+}
+
+// Bool returns v's value as a bool. It panics
+// if v is not a bool.
+func (v Value) Bool() bool {
+	if g, w := v.Kind(), KindBool; g != w {
+		panic(fmt.Sprintf("Value kind is %s, not %s", g, w))
+	}
+	return v.bool()
+}
+
+func (v Value) bool() bool {
+	return v.num == 1
+}
+
+// Duration returns v's value as a time.Duration. It panics
+// if v is not a time.Duration.
+func (v Value) Duration() time.Duration {
+	if g, w := v.Kind(), KindDuration; g != w {
+		panic(fmt.Sprintf("Value kind is %s, not %s", g, w))
+	}
+
+	return v.duration()
+}
+
+func (v Value) duration() time.Duration {
+	return time.Duration(int64(v.num))
+}
+
+// Float64 returns v's value as a float64. It panics
+// if v is not a float64.
+func (v Value) Float64() float64 {
+	if g, w := v.Kind(), KindFloat64; g != w {
+		panic(fmt.Sprintf("Value kind is %s, not %s", g, w))
+	}
+
+	return v.float()
+}
+
+func (v Value) float() float64 {
+	return math.Float64frombits(v.num)
+}
+
+// Time returns v's value as a time.Time. It panics
+// if v is not a time.Time.
+func (v Value) Time() time.Time {
+	if g, w := v.Kind(), KindTime; g != w {
+		panic(fmt.Sprintf("Value kind is %s, not %s", g, w))
+	}
+	return v.time()
+}
+
+func (v Value) time() time.Time {
+	loc := v.any.(timeLocation)
+	if loc == nil {
+		return time.Time{}
+	}
+	return time.Unix(0, int64(v.num)).In(loc)
+}
+
+// LogValuer returns v's value as a LogValuer. It panics
+// if v is not a LogValuer.
+func (v Value) LogValuer() LogValuer {
+	return v.any.(LogValuer)
+}
+
+// Group returns v's value as a []Attr.
+// It panics if v's Kind is not KindGroup.
+func (v Value) Group() []Attr {
+	if sp, ok := v.any.(groupptr); ok {
+		return unsafe.Slice((*Attr)(sp), v.num)
+	}
+	panic("Group: bad kind")
+}
+
+func (v Value) group() []Attr {
+	return unsafe.Slice((*Attr)(v.any.(groupptr)), v.num)
+}
+
+//////////////// Other
+
+// Equal reports whether v and w represent the same Go value.
+func (v Value) Equal(w Value) bool {
+	k1 := v.Kind()
+	k2 := w.Kind()
+	if k1 != k2 {
+		return false
+	}
+	switch k1 {
+	case KindInt64, KindUint64, KindBool, KindDuration:
+		return v.num == w.num
+	case KindString:
+		return v.str() == w.str()
+	case KindFloat64:
+		return v.float() == w.float()
+	case KindTime:
+		return v.time().Equal(w.time())
+	case KindAny, KindLogValuer:
+		return v.any == w.any // may panic if non-comparable
+	case KindGroup:
+		return slices.EqualFunc(v.group(), w.group(), Attr.Equal)
+	default:
+		panic(fmt.Sprintf("bad kind: %s", k1))
+	}
+}
+
+// append appends a text representation of v to dst.
+// v is formatted as with fmt.Sprint.
+func (v Value) append(dst []byte) []byte {
+	switch v.Kind() {
+	case KindString:
+		return append(dst, v.str()...)
+	case KindInt64:
+		return strconv.AppendInt(dst, int64(v.num), 10)
+	case KindUint64:
+		return strconv.AppendUint(dst, v.num, 10)
+	case KindFloat64:
+		return strconv.AppendFloat(dst, v.float(), 'g', -1, 64)
+	case KindBool:
+		return strconv.AppendBool(dst, v.bool())
+	case KindDuration:
+		return append(dst, v.duration().String()...)
+	case KindTime:
+		return append(dst, v.time().String()...)
+	case KindGroup:
+		return fmt.Append(dst, v.group())
+	case KindAny, KindLogValuer:
+		return fmt.Append(dst, v.any)
+	default:
+		panic(fmt.Sprintf("bad kind: %s", v.Kind()))
+	}
+}
+
+// A LogValuer is any Go value that can convert itself into a Value for logging.
+//
+// This mechanism may be used to defer expensive operations until they are
+// needed, or to expand a single value into a sequence of components.
+type LogValuer interface {
+	LogValue() Value
+}
+
+const maxLogValues = 100
+
+// Resolve repeatedly calls LogValue on v while it implements LogValuer,
+// and returns the result.
+// If v resolves to a group, the group's attributes' values are not recursively
+// resolved.
+// If the number of LogValue calls exceeds a threshold, a Value containing an
+// error is returned.
+// Resolve's return value is guaranteed not to be of Kind KindLogValuer.
+func (v Value) Resolve() (rv Value) {
+	orig := v
+	defer func() {
+		if r := recover(); r != nil {
+			rv = AnyValue(fmt.Errorf("LogValue panicked\n%s", stack(3, 5)))
+		}
+	}()
+
+	for i := 0; i < maxLogValues; i++ {
+		if v.Kind() != KindLogValuer {
+			return v
+		}
+		v = v.LogValuer().LogValue()
+	}
+	err := fmt.Errorf("LogValue called too many times on Value of type %T", orig.Any())
+	return AnyValue(err)
+}
+
+func stack(skip, nFrames int) string {
+	pcs := make([]uintptr, nFrames+1)
+	n := runtime.Callers(skip+1, pcs)
+	if n == 0 {
+		return "(no stack)"
+	}
+	frames := runtime.CallersFrames(pcs[:n])
+	var b strings.Builder
+	i := 0
+	for {
+		frame, more := frames.Next()
+		fmt.Fprintf(&b, "called from %s (%s:%d)\n", frame.Function, frame.File, frame.Line)
+		if !more {
+			break
+		}
+		i++
+		if i >= nFrames {
+			fmt.Fprintf(&b, "(rest of stack elided)\n")
+			break
+		}
+	}
+	return b.String()
+}