Skip to content
Permalink
Branch: master
Find file Copy path
Find file Copy path
6 contributors

Users who have contributed to this file

@BurntSushi @cespare @source-gisakulabs @sethwklein @sqs @mrdg
510 lines (473 sloc) 14.1 KB
package toml
import (
"fmt"
"io"
"io/ioutil"
"math"
"reflect"
"strings"
"time"
)
func e(format string, args ...interface{}) error {
return fmt.Errorf("toml: "+format, args...)
}
// Unmarshaler is the interface implemented by objects that can unmarshal a
// TOML description of themselves.
type Unmarshaler interface {
UnmarshalTOML(interface{}) error
}
// Unmarshal decodes the contents of `p` in TOML format into a pointer `v`.
func Unmarshal(p []byte, v interface{}) error {
_, err := Decode(string(p), v)
return err
}
// Primitive is a TOML value that hasn't been decoded into a Go value.
// When using the various `Decode*` functions, the type `Primitive` may
// be given to any value, and its decoding will be delayed.
//
// A `Primitive` value can be decoded using the `PrimitiveDecode` function.
//
// The underlying representation of a `Primitive` value is subject to change.
// Do not rely on it.
//
// N.B. Primitive values are still parsed, so using them will only avoid
// the overhead of reflection. They can be useful when you don't know the
// exact type of TOML data until run time.
type Primitive struct {
undecoded interface{}
context Key
}
// DEPRECATED!
//
// Use MetaData.PrimitiveDecode instead.
func PrimitiveDecode(primValue Primitive, v interface{}) error {
md := MetaData{decoded: make(map[string]bool)}
return md.unify(primValue.undecoded, rvalue(v))
}
// PrimitiveDecode is just like the other `Decode*` functions, except it
// decodes a TOML value that has already been parsed. Valid primitive values
// can *only* be obtained from values filled by the decoder functions,
// including this method. (i.e., `v` may contain more `Primitive`
// values.)
//
// Meta data for primitive values is included in the meta data returned by
// the `Decode*` functions with one exception: keys returned by the Undecoded
// method will only reflect keys that were decoded. Namely, any keys hidden
// behind a Primitive will be considered undecoded. Executing this method will
// update the undecoded keys in the meta data. (See the example.)
func (md *MetaData) PrimitiveDecode(primValue Primitive, v interface{}) error {
md.context = primValue.context
defer func() { md.context = nil }()
return md.unify(primValue.undecoded, rvalue(v))
}
// Decode will decode the contents of `data` in TOML format into a pointer
// `v`.
//
// TOML hashes correspond to Go structs or maps. (Dealer's choice. They can be
// used interchangeably.)
//
// TOML arrays of tables correspond to either a slice of structs or a slice
// of maps.
//
// TOML datetimes correspond to Go `time.Time` values.
//
// All other TOML types (float, string, int, bool and array) correspond
// to the obvious Go types.
//
// An exception to the above rules is if a type implements the
// encoding.TextUnmarshaler interface. In this case, any primitive TOML value
// (floats, strings, integers, booleans and datetimes) will be converted to
// a byte string and given to the value's UnmarshalText method. See the
// Unmarshaler example for a demonstration with time duration strings.
//
// Key mapping
//
// TOML keys can map to either keys in a Go map or field names in a Go
// struct. The special `toml` struct tag may be used to map TOML keys to
// struct fields that don't match the key name exactly. (See the example.)
// A case insensitive match to struct names will be tried if an exact match
// can't be found.
//
// The mapping between TOML values and Go values is loose. That is, there
// may exist TOML values that cannot be placed into your representation, and
// there may be parts of your representation that do not correspond to
// TOML values. This loose mapping can be made stricter by using the IsDefined
// and/or Undecoded methods on the MetaData returned.
//
// This decoder will not handle cyclic types. If a cyclic type is passed,
// `Decode` will not terminate.
func Decode(data string, v interface{}) (MetaData, error) {
rv := reflect.ValueOf(v)
if rv.Kind() != reflect.Ptr {
return MetaData{}, e("Decode of non-pointer %s", reflect.TypeOf(v))
}
if rv.IsNil() {
return MetaData{}, e("Decode of nil %s", reflect.TypeOf(v))
}
p, err := parse(data)
if err != nil {
return MetaData{}, err
}
md := MetaData{
p.mapping, p.types, p.ordered,
make(map[string]bool, len(p.ordered)), nil,
}
return md, md.unify(p.mapping, indirect(rv))
}
// DecodeFile is just like Decode, except it will automatically read the
// contents of the file at `fpath` and decode it for you.
func DecodeFile(fpath string, v interface{}) (MetaData, error) {
bs, err := ioutil.ReadFile(fpath)
if err != nil {
return MetaData{}, err
}
return Decode(string(bs), v)
}
// DecodeReader is just like Decode, except it will consume all bytes
// from the reader and decode it for you.
func DecodeReader(r io.Reader, v interface{}) (MetaData, error) {
bs, err := ioutil.ReadAll(r)
if err != nil {
return MetaData{}, err
}
return Decode(string(bs), v)
}
// unify performs a sort of type unification based on the structure of `rv`,
// which is the client representation.
//
// Any type mismatch produces an error. Finding a type that we don't know
// how to handle produces an unsupported type error.
func (md *MetaData) unify(data interface{}, rv reflect.Value) error {
// Special case. Look for a `Primitive` value.
if rv.Type() == reflect.TypeOf((*Primitive)(nil)).Elem() {
// Save the undecoded data and the key context into the primitive
// value.
context := make(Key, len(md.context))
copy(context, md.context)
rv.Set(reflect.ValueOf(Primitive{
undecoded: data,
context: context,
}))
return nil
}
// Special case. Unmarshaler Interface support.
if rv.CanAddr() {
if v, ok := rv.Addr().Interface().(Unmarshaler); ok {
return v.UnmarshalTOML(data)
}
}
// Special case. Handle time.Time values specifically.
// TODO: Remove this code when we decide to drop support for Go 1.1.
// This isn't necessary in Go 1.2 because time.Time satisfies the encoding
// interfaces.
if rv.Type().AssignableTo(rvalue(time.Time{}).Type()) {
return md.unifyDatetime(data, rv)
}
// Special case. Look for a value satisfying the TextUnmarshaler interface.
if v, ok := rv.Interface().(TextUnmarshaler); ok {
return md.unifyText(data, v)
}
// BUG(burntsushi)
// The behavior here is incorrect whenever a Go type satisfies the
// encoding.TextUnmarshaler interface but also corresponds to a TOML
// hash or array. In particular, the unmarshaler should only be applied
// to primitive TOML values. But at this point, it will be applied to
// all kinds of values and produce an incorrect error whenever those values
// are hashes or arrays (including arrays of tables).
k := rv.Kind()
// laziness
if k >= reflect.Int && k <= reflect.Uint64 {
return md.unifyInt(data, rv)
}
switch k {
case reflect.Ptr:
elem := reflect.New(rv.Type().Elem())
err := md.unify(data, reflect.Indirect(elem))
if err != nil {
return err
}
rv.Set(elem)
return nil
case reflect.Struct:
return md.unifyStruct(data, rv)
case reflect.Map:
return md.unifyMap(data, rv)
case reflect.Array:
return md.unifyArray(data, rv)
case reflect.Slice:
return md.unifySlice(data, rv)
case reflect.String:
return md.unifyString(data, rv)
case reflect.Bool:
return md.unifyBool(data, rv)
case reflect.Interface:
// we only support empty interfaces.
if rv.NumMethod() > 0 {
return e("unsupported type %s", rv.Type())
}
return md.unifyAnything(data, rv)
case reflect.Float32:
fallthrough
case reflect.Float64:
return md.unifyFloat64(data, rv)
}
return e("unsupported type %s", rv.Kind())
}
func (md *MetaData) unifyStruct(mapping interface{}, rv reflect.Value) error {
tmap, ok := mapping.(map[string]interface{})
if !ok {
if mapping == nil {
return nil
}
return e("type mismatch for %s: expected table but found %T",
rv.Type().String(), mapping)
}
for key, datum := range tmap {
var f *field
fields := cachedTypeFields(rv.Type())
for i := range fields {
ff := &fields[i]
if ff.name == key {
f = ff
break
}
if f == nil && strings.EqualFold(ff.name, key) {
f = ff
}
}
if f != nil {
subv := rv
for _, i := range f.index {
subv = indirect(subv.Field(i))
}
if isUnifiable(subv) {
md.decoded[md.context.add(key).String()] = true
md.context = append(md.context, key)
if err := md.unify(datum, subv); err != nil {
return err
}
md.context = md.context[0 : len(md.context)-1]
} else if f.name != "" {
// Bad user! No soup for you!
return e("cannot write unexported field %s.%s",
rv.Type().String(), f.name)
}
}
}
return nil
}
func (md *MetaData) unifyMap(mapping interface{}, rv reflect.Value) error {
tmap, ok := mapping.(map[string]interface{})
if !ok {
if tmap == nil {
return nil
}
return badtype("map", mapping)
}
if rv.IsNil() {
rv.Set(reflect.MakeMap(rv.Type()))
}
for k, v := range tmap {
md.decoded[md.context.add(k).String()] = true
md.context = append(md.context, k)
rvkey := indirect(reflect.New(rv.Type().Key()))
rvval := reflect.Indirect(reflect.New(rv.Type().Elem()))
if err := md.unify(v, rvval); err != nil {
return err
}
md.context = md.context[0 : len(md.context)-1]
rvkey.SetString(k)
rv.SetMapIndex(rvkey, rvval)
}
return nil
}
func (md *MetaData) unifyArray(data interface{}, rv reflect.Value) error {
datav := reflect.ValueOf(data)
if datav.Kind() != reflect.Slice {
if !datav.IsValid() {
return nil
}
return badtype("slice", data)
}
sliceLen := datav.Len()
if sliceLen != rv.Len() {
return e("expected array length %d; got TOML array of length %d",
rv.Len(), sliceLen)
}
return md.unifySliceArray(datav, rv)
}
func (md *MetaData) unifySlice(data interface{}, rv reflect.Value) error {
datav := reflect.ValueOf(data)
if datav.Kind() != reflect.Slice {
if !datav.IsValid() {
return nil
}
return badtype("slice", data)
}
n := datav.Len()
if rv.IsNil() || rv.Cap() < n {
rv.Set(reflect.MakeSlice(rv.Type(), n, n))
}
rv.SetLen(n)
return md.unifySliceArray(datav, rv)
}
func (md *MetaData) unifySliceArray(data, rv reflect.Value) error {
sliceLen := data.Len()
for i := 0; i < sliceLen; i++ {
v := data.Index(i).Interface()
sliceval := indirect(rv.Index(i))
if err := md.unify(v, sliceval); err != nil {
return err
}
}
return nil
}
func (md *MetaData) unifyDatetime(data interface{}, rv reflect.Value) error {
if _, ok := data.(time.Time); ok {
rv.Set(reflect.ValueOf(data))
return nil
}
return badtype("time.Time", data)
}
func (md *MetaData) unifyString(data interface{}, rv reflect.Value) error {
if s, ok := data.(string); ok {
rv.SetString(s)
return nil
}
return badtype("string", data)
}
func (md *MetaData) unifyFloat64(data interface{}, rv reflect.Value) error {
if num, ok := data.(float64); ok {
switch rv.Kind() {
case reflect.Float32:
fallthrough
case reflect.Float64:
rv.SetFloat(num)
default:
panic("bug")
}
return nil
}
return badtype("float", data)
}
func (md *MetaData) unifyInt(data interface{}, rv reflect.Value) error {
if num, ok := data.(int64); ok {
if rv.Kind() >= reflect.Int && rv.Kind() <= reflect.Int64 {
switch rv.Kind() {
case reflect.Int, reflect.Int64:
// No bounds checking necessary.
case reflect.Int8:
if num < math.MinInt8 || num > math.MaxInt8 {
return e("value %d is out of range for int8", num)
}
case reflect.Int16:
if num < math.MinInt16 || num > math.MaxInt16 {
return e("value %d is out of range for int16", num)
}
case reflect.Int32:
if num < math.MinInt32 || num > math.MaxInt32 {
return e("value %d is out of range for int32", num)
}
}
rv.SetInt(num)
} else if rv.Kind() >= reflect.Uint && rv.Kind() <= reflect.Uint64 {
unum := uint64(num)
switch rv.Kind() {
case reflect.Uint, reflect.Uint64:
// No bounds checking necessary.
case reflect.Uint8:
if num < 0 || unum > math.MaxUint8 {
return e("value %d is out of range for uint8", num)
}
case reflect.Uint16:
if num < 0 || unum > math.MaxUint16 {
return e("value %d is out of range for uint16", num)
}
case reflect.Uint32:
if num < 0 || unum > math.MaxUint32 {
return e("value %d is out of range for uint32", num)
}
}
rv.SetUint(unum)
} else {
panic("unreachable")
}
return nil
}
return badtype("integer", data)
}
func (md *MetaData) unifyBool(data interface{}, rv reflect.Value) error {
if b, ok := data.(bool); ok {
rv.SetBool(b)
return nil
}
return badtype("boolean", data)
}
func (md *MetaData) unifyAnything(data interface{}, rv reflect.Value) error {
rv.Set(reflect.ValueOf(data))
return nil
}
func (md *MetaData) unifyText(data interface{}, v TextUnmarshaler) error {
var s string
switch sdata := data.(type) {
case TextMarshaler:
text, err := sdata.MarshalText()
if err != nil {
return err
}
s = string(text)
case fmt.Stringer:
s = sdata.String()
case string:
s = sdata
case bool:
s = fmt.Sprintf("%v", sdata)
case int64:
s = fmt.Sprintf("%d", sdata)
case float64:
s = fmt.Sprintf("%f", sdata)
default:
return badtype("primitive (string-like)", data)
}
if err := v.UnmarshalText([]byte(s)); err != nil {
return err
}
return nil
}
// rvalue returns a reflect.Value of `v`. All pointers are resolved.
func rvalue(v interface{}) reflect.Value {
return indirect(reflect.ValueOf(v))
}
// indirect returns the value pointed to by a pointer.
// Pointers are followed until the value is not a pointer.
// New values are allocated for each nil pointer.
//
// An exception to this rule is if the value satisfies an interface of
// interest to us (like encoding.TextUnmarshaler).
func indirect(v reflect.Value) reflect.Value {
if v.Kind() != reflect.Ptr {
if v.CanSet() {
pv := v.Addr()
if _, ok := pv.Interface().(TextUnmarshaler); ok {
return pv
}
}
return v
}
if v.IsNil() {
v.Set(reflect.New(v.Type().Elem()))
}
return indirect(reflect.Indirect(v))
}
func isUnifiable(rv reflect.Value) bool {
if rv.CanSet() {
return true
}
if _, ok := rv.Interface().(TextUnmarshaler); ok {
return true
}
return false
}
func badtype(expected string, data interface{}) error {
return e("cannot load TOML value of type %T into a Go %s", data, expected)
}
You can’t perform that action at this time.