David K. Bainbridge | c415efe | 2021-08-19 13:05:21 +0000 | [diff] [blame] | 1 | // Copyright 2020, The Go Authors. All rights reserved. |
| 2 | // Use of this source code is governed by a BSD-style |
| 3 | // license that can be found in the LICENSE file. |
| 4 | |
| 5 | package value |
| 6 | |
| 7 | import ( |
| 8 | "reflect" |
| 9 | "strconv" |
| 10 | ) |
| 11 | |
| 12 | // TypeString is nearly identical to reflect.Type.String, |
| 13 | // but has an additional option to specify that full type names be used. |
| 14 | func TypeString(t reflect.Type, qualified bool) string { |
| 15 | return string(appendTypeName(nil, t, qualified, false)) |
| 16 | } |
| 17 | |
| 18 | func appendTypeName(b []byte, t reflect.Type, qualified, elideFunc bool) []byte { |
| 19 | // BUG: Go reflection provides no way to disambiguate two named types |
| 20 | // of the same name and within the same package, |
| 21 | // but declared within the namespace of different functions. |
| 22 | |
| 23 | // Named type. |
| 24 | if t.Name() != "" { |
| 25 | if qualified && t.PkgPath() != "" { |
| 26 | b = append(b, '"') |
| 27 | b = append(b, t.PkgPath()...) |
| 28 | b = append(b, '"') |
| 29 | b = append(b, '.') |
| 30 | b = append(b, t.Name()...) |
| 31 | } else { |
| 32 | b = append(b, t.String()...) |
| 33 | } |
| 34 | return b |
| 35 | } |
| 36 | |
| 37 | // Unnamed type. |
| 38 | switch k := t.Kind(); k { |
| 39 | case reflect.Bool, reflect.String, reflect.UnsafePointer, |
| 40 | reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64, |
| 41 | reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr, |
| 42 | reflect.Float32, reflect.Float64, reflect.Complex64, reflect.Complex128: |
| 43 | b = append(b, k.String()...) |
| 44 | case reflect.Chan: |
| 45 | if t.ChanDir() == reflect.RecvDir { |
| 46 | b = append(b, "<-"...) |
| 47 | } |
| 48 | b = append(b, "chan"...) |
| 49 | if t.ChanDir() == reflect.SendDir { |
| 50 | b = append(b, "<-"...) |
| 51 | } |
| 52 | b = append(b, ' ') |
| 53 | b = appendTypeName(b, t.Elem(), qualified, false) |
| 54 | case reflect.Func: |
| 55 | if !elideFunc { |
| 56 | b = append(b, "func"...) |
| 57 | } |
| 58 | b = append(b, '(') |
| 59 | for i := 0; i < t.NumIn(); i++ { |
| 60 | if i > 0 { |
| 61 | b = append(b, ", "...) |
| 62 | } |
| 63 | if i == t.NumIn()-1 && t.IsVariadic() { |
| 64 | b = append(b, "..."...) |
| 65 | b = appendTypeName(b, t.In(i).Elem(), qualified, false) |
| 66 | } else { |
| 67 | b = appendTypeName(b, t.In(i), qualified, false) |
| 68 | } |
| 69 | } |
| 70 | b = append(b, ')') |
| 71 | switch t.NumOut() { |
| 72 | case 0: |
| 73 | // Do nothing |
| 74 | case 1: |
| 75 | b = append(b, ' ') |
| 76 | b = appendTypeName(b, t.Out(0), qualified, false) |
| 77 | default: |
| 78 | b = append(b, " ("...) |
| 79 | for i := 0; i < t.NumOut(); i++ { |
| 80 | if i > 0 { |
| 81 | b = append(b, ", "...) |
| 82 | } |
| 83 | b = appendTypeName(b, t.Out(i), qualified, false) |
| 84 | } |
| 85 | b = append(b, ')') |
| 86 | } |
| 87 | case reflect.Struct: |
| 88 | b = append(b, "struct{ "...) |
| 89 | for i := 0; i < t.NumField(); i++ { |
| 90 | if i > 0 { |
| 91 | b = append(b, "; "...) |
| 92 | } |
| 93 | sf := t.Field(i) |
| 94 | if !sf.Anonymous { |
| 95 | if qualified && sf.PkgPath != "" { |
| 96 | b = append(b, '"') |
| 97 | b = append(b, sf.PkgPath...) |
| 98 | b = append(b, '"') |
| 99 | b = append(b, '.') |
| 100 | } |
| 101 | b = append(b, sf.Name...) |
| 102 | b = append(b, ' ') |
| 103 | } |
| 104 | b = appendTypeName(b, sf.Type, qualified, false) |
| 105 | if sf.Tag != "" { |
| 106 | b = append(b, ' ') |
| 107 | b = strconv.AppendQuote(b, string(sf.Tag)) |
| 108 | } |
| 109 | } |
| 110 | if b[len(b)-1] == ' ' { |
| 111 | b = b[:len(b)-1] |
| 112 | } else { |
| 113 | b = append(b, ' ') |
| 114 | } |
| 115 | b = append(b, '}') |
| 116 | case reflect.Slice, reflect.Array: |
| 117 | b = append(b, '[') |
| 118 | if k == reflect.Array { |
| 119 | b = strconv.AppendUint(b, uint64(t.Len()), 10) |
| 120 | } |
| 121 | b = append(b, ']') |
| 122 | b = appendTypeName(b, t.Elem(), qualified, false) |
| 123 | case reflect.Map: |
| 124 | b = append(b, "map["...) |
| 125 | b = appendTypeName(b, t.Key(), qualified, false) |
| 126 | b = append(b, ']') |
| 127 | b = appendTypeName(b, t.Elem(), qualified, false) |
| 128 | case reflect.Ptr: |
| 129 | b = append(b, '*') |
| 130 | b = appendTypeName(b, t.Elem(), qualified, false) |
| 131 | case reflect.Interface: |
| 132 | b = append(b, "interface{ "...) |
| 133 | for i := 0; i < t.NumMethod(); i++ { |
| 134 | if i > 0 { |
| 135 | b = append(b, "; "...) |
| 136 | } |
| 137 | m := t.Method(i) |
| 138 | if qualified && m.PkgPath != "" { |
| 139 | b = append(b, '"') |
| 140 | b = append(b, m.PkgPath...) |
| 141 | b = append(b, '"') |
| 142 | b = append(b, '.') |
| 143 | } |
| 144 | b = append(b, m.Name...) |
| 145 | b = appendTypeName(b, m.Type, qualified, true) |
| 146 | } |
| 147 | if b[len(b)-1] == ' ' { |
| 148 | b = b[:len(b)-1] |
| 149 | } else { |
| 150 | b = append(b, ' ') |
| 151 | } |
| 152 | b = append(b, '}') |
| 153 | default: |
| 154 | panic("invalid kind: " + k.String()) |
| 155 | } |
| 156 | return b |
| 157 | } |