package toml import ( "fmt" "io" "io/ioutil" "math" "reflect" "strings" "time" ) var e = fmt.Errorf // 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) { 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, rvalue(v)) } // 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.Kind()) } 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 { return mismatch(rv, "map", 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 e("Type mismatch for '%s.%s': %s", rv.Type().String(), f.name, err) } md.context = md.context[0 : len(md.context)-1] } else if f.name != "" { // Bad user! No soup for you! return e("Field '%s.%s' is unexported, and therefore cannot "+ "be loaded with reflection.", 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 { 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 { 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 { return badtype("slice", data) } sliceLen := datav.Len() if rv.IsNil() { rv.Set(reflect.MakeSlice(rv.Type(), sliceLen, sliceLen)) } 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.CanAddr() { 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("Expected %s but found '%T'.", expected, data) } func mismatch(user reflect.Value, expected string, data interface{}) error { return e("Type mismatch for %s. Expected %s but found '%T'.", user.Type().String(), expected, data) }