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Diffstat (limited to 'vendor/github.com/magiconair/properties/decode.go')
-rw-r--r-- | vendor/github.com/magiconair/properties/decode.go | 289 |
1 files changed, 289 insertions, 0 deletions
diff --git a/vendor/github.com/magiconair/properties/decode.go b/vendor/github.com/magiconair/properties/decode.go new file mode 100644 index 00000000..0a961bb0 --- /dev/null +++ b/vendor/github.com/magiconair/properties/decode.go @@ -0,0 +1,289 @@ +// Copyright 2017 Frank Schroeder. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package properties + +import ( + "fmt" + "reflect" + "strconv" + "strings" + "time" +) + +// Decode assigns property values to exported fields of a struct. +// +// Decode traverses v recursively and returns an error if a value cannot be +// converted to the field type or a required value is missing for a field. +// +// The following type dependent decodings are used: +// +// String, boolean, numeric fields have the value of the property key assigned. +// The property key name is the name of the field. A different key and a default +// value can be set in the field's tag. Fields without default value are +// required. If the value cannot be converted to the field type an error is +// returned. +// +// time.Duration fields have the result of time.ParseDuration() assigned. +// +// time.Time fields have the vaule of time.Parse() assigned. The default layout +// is time.RFC3339 but can be set in the field's tag. +// +// Arrays and slices of string, boolean, numeric, time.Duration and time.Time +// fields have the value interpreted as a comma separated list of values. The +// individual values are trimmed of whitespace and empty values are ignored. A +// default value can be provided as a semicolon separated list in the field's +// tag. +// +// Struct fields are decoded recursively using the field name plus "." as +// prefix. The prefix (without dot) can be overridden in the field's tag. +// Default values are not supported in the field's tag. Specify them on the +// fields of the inner struct instead. +// +// Map fields must have a key of type string and are decoded recursively by +// using the field's name plus ".' as prefix and the next element of the key +// name as map key. The prefix (without dot) can be overridden in the field's +// tag. Default values are not supported. +// +// Examples: +// +// // Field is ignored. +// Field int `properties:"-"` +// +// // Field is assigned value of 'Field'. +// Field int +// +// // Field is assigned value of 'myName'. +// Field int `properties:"myName"` +// +// // Field is assigned value of key 'myName' and has a default +// // value 15 if the key does not exist. +// Field int `properties:"myName,default=15"` +// +// // Field is assigned value of key 'Field' and has a default +// // value 15 if the key does not exist. +// Field int `properties:",default=15"` +// +// // Field is assigned value of key 'date' and the date +// // is in format 2006-01-02 +// Field time.Time `properties:"date,layout=2006-01-02"` +// +// // Field is assigned the non-empty and whitespace trimmed +// // values of key 'Field' split by commas. +// Field []string +// +// // Field is assigned the non-empty and whitespace trimmed +// // values of key 'Field' split by commas and has a default +// // value ["a", "b", "c"] if the key does not exist. +// Field []string `properties:",default=a;b;c"` +// +// // Field is decoded recursively with "Field." as key prefix. +// Field SomeStruct +// +// // Field is decoded recursively with "myName." as key prefix. +// Field SomeStruct `properties:"myName"` +// +// // Field is decoded recursively with "Field." as key prefix +// // and the next dotted element of the key as map key. +// Field map[string]string +// +// // Field is decoded recursively with "myName." as key prefix +// // and the next dotted element of the key as map key. +// Field map[string]string `properties:"myName"` +func (p *Properties) Decode(x interface{}) error { + t, v := reflect.TypeOf(x), reflect.ValueOf(x) + if t.Kind() != reflect.Ptr || v.Elem().Type().Kind() != reflect.Struct { + return fmt.Errorf("not a pointer to struct: %s", t) + } + if err := dec(p, "", nil, nil, v); err != nil { + return err + } + return nil +} + +func dec(p *Properties, key string, def *string, opts map[string]string, v reflect.Value) error { + t := v.Type() + + // value returns the property value for key or the default if provided. + value := func() (string, error) { + if val, ok := p.Get(key); ok { + return val, nil + } + if def != nil { + return *def, nil + } + return "", fmt.Errorf("missing required key %s", key) + } + + // conv converts a string to a value of the given type. + conv := func(s string, t reflect.Type) (val reflect.Value, err error) { + var v interface{} + + switch { + case isDuration(t): + v, err = time.ParseDuration(s) + + case isTime(t): + layout := opts["layout"] + if layout == "" { + layout = time.RFC3339 + } + v, err = time.Parse(layout, s) + + case isBool(t): + v, err = boolVal(s), nil + + case isString(t): + v, err = s, nil + + case isFloat(t): + v, err = strconv.ParseFloat(s, 64) + + case isInt(t): + v, err = strconv.ParseInt(s, 10, 64) + + case isUint(t): + v, err = strconv.ParseUint(s, 10, 64) + + default: + return reflect.Zero(t), fmt.Errorf("unsupported type %s", t) + } + if err != nil { + return reflect.Zero(t), err + } + return reflect.ValueOf(v).Convert(t), nil + } + + // keydef returns the property key and the default value based on the + // name of the struct field and the options in the tag. + keydef := func(f reflect.StructField) (string, *string, map[string]string) { + _key, _opts := parseTag(f.Tag.Get("properties")) + + var _def *string + if d, ok := _opts["default"]; ok { + _def = &d + } + if _key != "" { + return _key, _def, _opts + } + return f.Name, _def, _opts + } + + switch { + case isDuration(t) || isTime(t) || isBool(t) || isString(t) || isFloat(t) || isInt(t) || isUint(t): + s, err := value() + if err != nil { + return err + } + val, err := conv(s, t) + if err != nil { + return err + } + v.Set(val) + + case isPtr(t): + return dec(p, key, def, opts, v.Elem()) + + case isStruct(t): + for i := 0; i < v.NumField(); i++ { + fv := v.Field(i) + fk, def, opts := keydef(t.Field(i)) + if !fv.CanSet() { + return fmt.Errorf("cannot set %s", t.Field(i).Name) + } + if fk == "-" { + continue + } + if key != "" { + fk = key + "." + fk + } + if err := dec(p, fk, def, opts, fv); err != nil { + return err + } + } + return nil + + case isArray(t): + val, err := value() + if err != nil { + return err + } + vals := split(val, ";") + a := reflect.MakeSlice(t, 0, len(vals)) + for _, s := range vals { + val, err := conv(s, t.Elem()) + if err != nil { + return err + } + a = reflect.Append(a, val) + } + v.Set(a) + + case isMap(t): + valT := t.Elem() + m := reflect.MakeMap(t) + for postfix := range p.FilterStripPrefix(key + ".").m { + pp := strings.SplitN(postfix, ".", 2) + mk, mv := pp[0], reflect.New(valT) + if err := dec(p, key+"."+mk, nil, nil, mv); err != nil { + return err + } + m.SetMapIndex(reflect.ValueOf(mk), mv.Elem()) + } + v.Set(m) + + default: + return fmt.Errorf("unsupported type %s", t) + } + return nil +} + +// split splits a string on sep, trims whitespace of elements +// and omits empty elements +func split(s string, sep string) []string { + var a []string + for _, v := range strings.Split(s, sep) { + if v = strings.TrimSpace(v); v != "" { + a = append(a, v) + } + } + return a +} + +// parseTag parses a "key,k=v,k=v,..." +func parseTag(tag string) (key string, opts map[string]string) { + opts = map[string]string{} + for i, s := range strings.Split(tag, ",") { + if i == 0 { + key = s + continue + } + + pp := strings.SplitN(s, "=", 2) + if len(pp) == 1 { + opts[pp[0]] = "" + } else { + opts[pp[0]] = pp[1] + } + } + return key, opts +} + +func isArray(t reflect.Type) bool { return t.Kind() == reflect.Array || t.Kind() == reflect.Slice } +func isBool(t reflect.Type) bool { return t.Kind() == reflect.Bool } +func isDuration(t reflect.Type) bool { return t == reflect.TypeOf(time.Second) } +func isMap(t reflect.Type) bool { return t.Kind() == reflect.Map } +func isPtr(t reflect.Type) bool { return t.Kind() == reflect.Ptr } +func isString(t reflect.Type) bool { return t.Kind() == reflect.String } +func isStruct(t reflect.Type) bool { return t.Kind() == reflect.Struct } +func isTime(t reflect.Type) bool { return t == reflect.TypeOf(time.Time{}) } +func isFloat(t reflect.Type) bool { + return t.Kind() == reflect.Float32 || t.Kind() == reflect.Float64 +} +func isInt(t reflect.Type) bool { + return t.Kind() == reflect.Int || t.Kind() == reflect.Int8 || t.Kind() == reflect.Int16 || t.Kind() == reflect.Int32 || t.Kind() == reflect.Int64 +} +func isUint(t reflect.Type) bool { + return t.Kind() == reflect.Uint || t.Kind() == reflect.Uint8 || t.Kind() == reflect.Uint16 || t.Kind() == reflect.Uint32 || t.Kind() == reflect.Uint64 +} |