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Merge pull request #8 from muir/duration
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time.Duration & flag.Value
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@muir
muir committed Dec 29, 2021
2 parents 9edbedf + 3915e74 commit bbfdc44
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Showing 3 changed files with 186 additions and 81 deletions.
46 changes: 46 additions & 0 deletions setters.go
View file
@@ -0,0 +1,46 @@
package reflectutils

import (
"reflect"
"time"
)

func init() {
RegisterStringSetter(time.ParseDuration)
}

var settersByType = make(map[reflect.Type]reflect.Value)

// RegisterStringSetter registers functions that can be used to transform
// strings into specific types. The fn argument must be a function that
// takes a string and returns an arbitrary type and an error. An example
// of such a function is time.ParseDuration. Any call to RegisterStringSetter
// with a value that is not a function of that sort will panic.
//
// RegisterStringSetter is not thread safe and should probably only be
// used during init().
//
// These functions are used by MakeStringSetter() when there is an opportunity
// to do so.
func RegisterStringSetter(fn interface{}) {
v := reflect.ValueOf(fn)
if !v.IsValid() {
panic("call to RegisterStringSetter with an invalid value")
}
if v.Type().Kind() != reflect.Func {
panic("call to RegisterStringSetter with something other than a function")
}
if v.Type().NumIn() != 1 {
panic("call to RegisterStringSetter with something other than a function that takes one arg")
}
if v.Type().NumOut() != 2 {
panic("call to RegisterStringSetter with something other than a function that takes returns two values")
}
if v.Type().In(0) != reflect.TypeOf((*string)(nil)).Elem() {
panic("call to RegisterStringSetter with something other than a function that takes something other than string")
}
if v.Type().Out(1) != reflect.TypeOf((*error)(nil)).Elem() {
panic("call to RegisterStringSetter with something other than a function that returns something other than error")
}
settersByType[v.Type().Out(0)] = v
}
33 changes: 33 additions & 0 deletions unpack.go
View file
Expand Up @@ -2,6 +2,7 @@ package reflectutils

import (
"encoding"
"flag"
"reflect"
"strconv"
"strings"
Expand All @@ -10,6 +11,7 @@ import (
)

var textUnmarshallerType = reflect.TypeOf((*encoding.TextUnmarshaler)(nil)).Elem()
var flagValueType = reflect.TypeOf((*flag.Value)(nil)).Elem()

type stringSetterOpts struct {
split string
Expand Down Expand Up @@ -46,7 +48,11 @@ func SliceAppend(b bool) StringSetterArg {
// For arrays and slices, strings are split on comma to create the values for the
// elements.
//
// Any type that matches a type registered with RegisterStringSetter will be
// unpacked with the corresponding function. A string setter is pre-registered
// for time.Duration
// Anything that implements encoding.TextUnmarshaler will be unpacked that way.
// Anything that implements flag.Value will be unpacked that way.
//
// Maps, structs, channels, interfaces, channels, and funcs are not supported unless
// they happen to implent encoding.TextUnmarshaler.
Expand All @@ -58,6 +64,16 @@ func MakeStringSetter(t reflect.Type, optArgs ...StringSetterArg) (func(target r
for _, f := range optArgs {
f(&opts)
}
if setter, ok := settersByType[t]; ok {
return func(target reflect.Value, value string) error {
out := setter.Call([]reflect.Value{reflect.ValueOf(value)})
if !out[1].IsNil() {
return out[1].Interface().(error)
}
target.Set(out[0])
return nil
}, nil
}
if t.AssignableTo(textUnmarshallerType) {
return func(target reflect.Value, value string) error {
p := reflect.New(t.Elem())
Expand All @@ -75,6 +91,23 @@ func MakeStringSetter(t reflect.Type, optArgs ...StringSetterArg) (func(target r
return errors.WithStack(err)
}, nil
}
if t.AssignableTo(flagValueType) {
return func(target reflect.Value, value string) error {
p := reflect.New(t.Elem())
target.Set(p)
err := target.Interface().(flag.Value).Set(value)
if err != nil {
return errors.WithStack(err)
}
return nil
}, nil
}
if reflect.PtrTo(t).AssignableTo(flagValueType) {
return func(target reflect.Value, value string) error {
err := target.Addr().Interface().(flag.Value).Set(value)
return errors.WithStack(err)
}, nil
}
switch t.Kind() {
case reflect.Ptr:
setElem, err := MakeStringSetter(t.Elem())
Expand Down
188 changes: 107 additions & 81 deletions unpack_test.go
View file
@@ -1,10 +1,13 @@
package reflectutils_test

import (
"encoding"
"flag"
"fmt"
"reflect"
"strconv"
"testing"
"time"

"github.com/muir/reflectutils"

Expand All @@ -19,98 +22,121 @@ func (fp *Foo) UnmarshalText(b []byte) error {
return nil
}

var _ encoding.TextUnmarshaler = func() *Foo { var x Foo; return &x }()

type Bar string

func (bp *Bar) Set(s string) error {
*bp = Bar(s + "/e")
return nil
}
func (bp Bar) String() string {
return "b/" + string(bp)
}

var _ flag.Value = func() *Bar { var x Bar; return &x }()

func TestStringSetter(t *testing.T) {
type tsType struct {
Int int `value:"38"`
Int8 int8 `value:"-9"`
Int16 int16 `value:"329"`
Int32 int32 `value:"-32902"`
Int64 int64 `value:"3292929"`
Uint uint `value:"202"`
Uint8 uint8 `value:"99"`
Uint16 uint16 `value:"3020"`
Uint32 uint32 `value:"92020"`
Uint64 uint64 `value:"320202"`
Float32 float32 `value:"3.9"`
Float64 float64 `value:"4.32e7" want:"4.32e+07"`
String string `value:"foo"`
Bool bool `value:"false"`
IntP *int `value:"-82"`
Int8P *int8 `value:"-2"`
Int16P *int16 `value:"-39"`
Int32P *int32 `value:"-329"`
Int64P *int64 `value:"-3292"`
UintP *uint `value:"239"`
Uint8P *uint8 `value:"92"`
Uint16P *uint16 `value:"330"`
Uint32P *uint32 `value:"239239"`
Uint64P *uint64 `value:"3923"`
Float32P *float32 `value:"3.299"`
Float64P *float64 `value:"9.2"`
StringP *string `value:"foop"`
Complex64 *complex64 `value:"4+3i" want:"(4+3i)"`
Complex128 *complex128 `value:"3.9+2.6i" want:"(3.9+2.6i)"`
BoolP *bool `value:"true"`
IntSlice []int `value:"3,9,-10" want:"[3 9 -10]"`
IntArray [2]int `value:"22,11" want:"[22 11]"`
Foo Foo `value:"foo" want:"~foo~"`
FooArray [2]Foo `value:"a,b,c" want:"[~a~ ~b,c~]"`
FooP *Foo `value:"foo" want:"~foo~"`
SS1 []string `value:"foo/bar" want:"[foo/bar]"`
SS2 []string `value:"foo/bar" want:"[foo bar]" split:"/"`
SS3 []string `value:"foo,bar" want:"[foo,bar]" split:""`
SS4 []string `value:"foo,bar" want:"[foo bar]" split:","`
SA1 [2]string `value:"foo/bar" want:"[foo/bar ]"`
SA2 [2]string `value:"foo/bar" want:"[foo bar]" split:"/"`
SA3 [2]string `value:"foo,bar" want:"[foo,bar ]" split:""`
SS5 []string `value:"foo" want:"[foo bar]" value2:"bar"`
SS6 []string `value:"foo" want:"[bar]" value2:"bar" sa:"f"`
Int int `value:"38"`
Int8 int8 `value:"-9"`
Int16 int16 `value:"329"`
Int32 int32 `value:"-32902"`
Int64 int64 `value:"3292929"`
Uint uint `value:"202"`
Uint8 uint8 `value:"99"`
Uint16 uint16 `value:"3020"`
Uint32 uint32 `value:"92020"`
Uint64 uint64 `value:"320202"`
Float32 float32 `value:"3.9"`
Float64 float64 `value:"4.32e7" want:"4.32e+07"`
String string `value:"foo"`
Bool bool `value:"false"`
IntP *int `value:"-82"`
Int8P *int8 `value:"-2"`
Int16P *int16 `value:"-39"`
Int32P *int32 `value:"-329"`
Int64P *int64 `value:"-3292"`
UintP *uint `value:"239"`
Uint8P *uint8 `value:"92"`
Uint16P *uint16 `value:"330"`
Uint32P *uint32 `value:"239239"`
Uint64P *uint64 `value:"3923"`
Float32P *float32 `value:"3.299"`
Float64P *float64 `value:"9.2"`
StringP *string `value:"foop"`
Complex64 *complex64 `value:"4+3i" want:"(4+3i)"`
Complex128 *complex128 `value:"3.9+2.6i" want:"(3.9+2.6i)"`
BoolP *bool `value:"true"`
IntSlice []int `value:"3,9,-10" want:"[3 9 -10]"`
IntArray [2]int `value:"22,11" want:"[22 11]"`
Foo Foo `value:"foo" want:"~foo~"`
FooArray [2]Foo `value:"a,b,c" want:"[~a~ ~b,c~]"`
FooP *Foo `value:"foo" want:"~foo~"`
Dur time.Duration `value:"30m" want:"30m0s"`
DurP *time.Duration `value:"15m" want:"15m0s"`
DurArray []time.Duration `value:"15m,45m" want:"[15m0s 45m0s]"`
Bar Bar `value:"bar" want:"b/bar/e"`
BarArray [2]Bar `value:"a,b,c" want:"[b/a/e b/b,c/e]"`
BarP *Bar `value:"bar" want:"b/bar/e"`
SS1 []string `value:"foo/bar" want:"[foo/bar]"`
SS2 []string `value:"foo/bar" want:"[foo bar]" split:"/"`
SS3 []string `value:"foo,bar" want:"[foo,bar]" split:""`
SS4 []string `value:"foo,bar" want:"[foo bar]" split:","`
SA1 [2]string `value:"foo/bar" want:"[foo/bar ]"`
SA2 [2]string `value:"foo/bar" want:"[foo bar]" split:"/"`
SA3 [2]string `value:"foo,bar" want:"[foo,bar ]" split:""`
SS5 []string `value:"foo" want:"[foo bar]" value2:"bar"`
SS6 []string `value:"foo" want:"[bar]" value2:"bar" sa:"f"`
}
var ts tsType
vp := reflect.ValueOf(&ts)
v := reflect.Indirect(vp)
var count int
reflectutils.WalkStructElements(v.Type(), func(f reflect.StructField) bool {
t.Logf("field %s, a %s", f.Name, f.Type)
value, ok := f.Tag.Lookup("value")
if !assert.Truef(t, ok, "input value for %s", f.Name) {
return true
}
want, ok := f.Tag.Lookup("want")
if !ok {
want = value
}
var opts []reflectutils.StringSetterArg
if split, ok := f.Tag.Lookup("split"); ok {
t.Log(" splitting on", split)
opts = append(opts, reflectutils.WithSplitOn(split))
}
if sa, ok := f.Tag.Lookup("sa"); ok {
b, err := strconv.ParseBool(sa)
require.NoError(t, err, "parse sa")
t.Log(" slice append", b)
opts = append(opts, reflectutils.SliceAppend(b))
}
t.Run(f.Name+"-"+f.Type.String(), func(t *testing.T) {
t.Logf("field %s, a %s", f.Name, f.Type)
value, ok := f.Tag.Lookup("value")
if !assert.Truef(t, ok, "input value for %s", f.Name) {
return
}
want, ok := f.Tag.Lookup("want")
if !ok {
want = value
}
var opts []reflectutils.StringSetterArg
if split, ok := f.Tag.Lookup("split"); ok {
t.Log(" splitting on", split)
opts = append(opts, reflectutils.WithSplitOn(split))
}
if sa, ok := f.Tag.Lookup("sa"); ok {
b, err := strconv.ParseBool(sa)
require.NoError(t, err, "parse sa")
t.Log(" slice append", b)
opts = append(opts, reflectutils.SliceAppend(b))
}

fn, err := reflectutils.MakeStringSetter(f.Type, opts...)
if !assert.NoErrorf(t, err, "make string setter for %s", f.Name) {
return true
}
e := v.FieldByIndex(f.Index)
err = fn(e, value)
if assert.NoError(t, err, "set %s to '%s'", f.Name, value) {
value2, ok := f.Tag.Lookup("value2")
if ok {
err := fn(e, value2)
assert.NoError(t, err, "set value2")
fn, err := reflectutils.MakeStringSetter(f.Type, opts...)
if !assert.NoErrorf(t, err, "make string setter for %s", f.Name) {
return
}
ge := e
if f.Type.Kind() == reflect.Ptr {
ge = e.Elem()
e := v.FieldByIndex(f.Index)
err = fn(e, value)
if assert.NoError(t, err, "set %s to '%s'", f.Name, value) {
value2, ok := f.Tag.Lookup("value2")
if ok {
err := fn(e, value2)
assert.NoError(t, err, "set value2")
}
ge := e
if f.Type.Kind() == reflect.Ptr {
ge = e.Elem()
}
assert.Equalf(t, want, fmt.Sprintf("%+v", ge.Interface()), "got setting %s to '%s'", f.Name, value)
}
assert.Equalf(t, want, fmt.Sprintf("%+v", ge.Interface()), "got setting %s to '%s'", f.Name, value)
}
count++
count++
return
})
return true
})
assert.Equal(t, v.NumField(), count, "number of fields tested")
Expand Down

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