1// Copyright 2015 Google Inc. All rights reserved.
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 proptools
16
17import "reflect"
18
19// TypeEqual takes two property structs, and returns true if they are of equal type, any embedded
20// pointers to structs or interfaces having matching nilitude, and any interface{} values in any
21// embedded structs, pointers to structs, or interfaces are also of equal type.
22func TypeEqual(s1, s2 interface{}) bool {
23	return typeEqual(reflect.ValueOf(s1), reflect.ValueOf(s2))
24}
25
26func typeEqual(v1, v2 reflect.Value) bool {
27	if v1.Type() != v2.Type() {
28		return false
29	}
30
31	if v1.Kind() == reflect.Interface {
32		if v1.IsNil() != v2.IsNil() {
33			return false
34		}
35		if v1.IsNil() {
36			return true
37		}
38		v1 = v1.Elem()
39		v2 = v2.Elem()
40		if v1.Type() != v2.Type() {
41			return false
42		}
43	}
44
45	if v1.Kind() == reflect.Ptr {
46		if v1.Type().Elem().Kind() != reflect.Struct {
47			return true
48		}
49		if v1.IsNil() && !v2.IsNil() {
50			return concreteType(v2)
51		} else if v2.IsNil() && !v1.IsNil() {
52			return concreteType(v1)
53		} else if v1.IsNil() && v2.IsNil() {
54			return true
55		}
56
57		v1 = v1.Elem()
58		v2 = v2.Elem()
59	}
60
61	if v1.Kind() != reflect.Struct {
62		return true
63	}
64
65	for i := 0; i < v1.NumField(); i++ {
66		v1 := v1.Field(i)
67		v2 := v2.Field(i)
68
69		switch kind := v1.Kind(); kind {
70		case reflect.Interface, reflect.Ptr, reflect.Struct:
71			if !typeEqual(v1, v2) {
72				return false
73			}
74		}
75	}
76
77	return true
78}
79
80// Returns true if v recursively contains no interfaces
81func concreteType(v reflect.Value) bool {
82	if v.Kind() == reflect.Interface {
83		return false
84	}
85
86	if v.Kind() == reflect.Ptr {
87		if v.IsNil() {
88			return true
89		}
90		v = v.Elem()
91	}
92
93	if v.Kind() != reflect.Struct {
94		return true
95	}
96
97	for i := 0; i < v.NumField(); i++ {
98		v := v.Field(i)
99
100		switch kind := v.Kind(); kind {
101		case reflect.Interface, reflect.Ptr, reflect.Struct:
102			if !concreteType(v) {
103				return false
104			}
105		}
106	}
107
108	return true
109}
110