1//  Copyright (c) 2014 Couchbase, Inc.
2//
3// Licensed under the Apache License, Version 2.0 (the "License");
4// you may not use this file except in compliance with the License.
5// You may obtain a copy of the License at
6//
7// 		http://www.apache.org/licenses/LICENSE-2.0
8//
9// Unless required by applicable law or agreed to in writing, software
10// distributed under the License is distributed on an "AS IS" BASIS,
11// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12// See the License for the specific language governing permissions and
13// limitations under the License.
14
15package mapping
16
17import (
18	"reflect"
19	"strings"
20)
21
22func lookupPropertyPath(data interface{}, path string) interface{} {
23	pathParts := decodePath(path)
24
25	current := data
26	for _, part := range pathParts {
27		current = lookupPropertyPathPart(current, part)
28		if current == nil {
29			break
30		}
31	}
32
33	return current
34}
35
36func lookupPropertyPathPart(data interface{}, part string) interface{} {
37	val := reflect.ValueOf(data)
38	typ := val.Type()
39	switch typ.Kind() {
40	case reflect.Map:
41		// FIXME can add support for other map keys in the future
42		if typ.Key().Kind() == reflect.String {
43			key := reflect.ValueOf(part)
44			entry := val.MapIndex(key)
45			if entry.IsValid() {
46				return entry.Interface()
47			}
48		}
49	case reflect.Struct:
50		field := val.FieldByName(part)
51		if field.IsValid() && field.CanInterface() {
52			return field.Interface()
53		}
54	case reflect.Ptr:
55		ptrElem := val.Elem()
56		if ptrElem.IsValid() && ptrElem.CanInterface() {
57			return lookupPropertyPathPart(ptrElem.Interface(), part)
58		}
59	}
60	return nil
61}
62
63const pathSeparator = "."
64
65func decodePath(path string) []string {
66	return strings.Split(path, pathSeparator)
67}
68
69func encodePath(pathElements []string) string {
70	return strings.Join(pathElements, pathSeparator)
71}
72
73func mustString(data interface{}) (string, bool) {
74	if data != nil {
75		str, ok := data.(string)
76		if ok {
77			return str, true
78		}
79	}
80	return "", false
81}
82
83// parseTagName extracts the field name from a struct tag
84func parseTagName(tag string) string {
85	if idx := strings.Index(tag, ","); idx != -1 {
86		return tag[:idx]
87	}
88	return tag
89}
90