Naveen Sampath | 04696f7 | 2022-06-13 15:19:14 +0530 | [diff] [blame^] | 1 | package hscan |
| 2 | |
| 3 | import ( |
| 4 | "errors" |
| 5 | "fmt" |
| 6 | "reflect" |
| 7 | "strconv" |
| 8 | ) |
| 9 | |
| 10 | // decoderFunc represents decoding functions for default built-in types. |
| 11 | type decoderFunc func(reflect.Value, string) error |
| 12 | |
| 13 | var ( |
| 14 | // List of built-in decoders indexed by their numeric constant values (eg: reflect.Bool = 1). |
| 15 | decoders = []decoderFunc{ |
| 16 | reflect.Bool: decodeBool, |
| 17 | reflect.Int: decodeInt, |
| 18 | reflect.Int8: decodeInt8, |
| 19 | reflect.Int16: decodeInt16, |
| 20 | reflect.Int32: decodeInt32, |
| 21 | reflect.Int64: decodeInt64, |
| 22 | reflect.Uint: decodeUint, |
| 23 | reflect.Uint8: decodeUint8, |
| 24 | reflect.Uint16: decodeUint16, |
| 25 | reflect.Uint32: decodeUint32, |
| 26 | reflect.Uint64: decodeUint64, |
| 27 | reflect.Float32: decodeFloat32, |
| 28 | reflect.Float64: decodeFloat64, |
| 29 | reflect.Complex64: decodeUnsupported, |
| 30 | reflect.Complex128: decodeUnsupported, |
| 31 | reflect.Array: decodeUnsupported, |
| 32 | reflect.Chan: decodeUnsupported, |
| 33 | reflect.Func: decodeUnsupported, |
| 34 | reflect.Interface: decodeUnsupported, |
| 35 | reflect.Map: decodeUnsupported, |
| 36 | reflect.Ptr: decodeUnsupported, |
| 37 | reflect.Slice: decodeSlice, |
| 38 | reflect.String: decodeString, |
| 39 | reflect.Struct: decodeUnsupported, |
| 40 | reflect.UnsafePointer: decodeUnsupported, |
| 41 | } |
| 42 | |
| 43 | // Global map of struct field specs that is populated once for every new |
| 44 | // struct type that is scanned. This caches the field types and the corresponding |
| 45 | // decoder functions to avoid iterating through struct fields on subsequent scans. |
| 46 | globalStructMap = newStructMap() |
| 47 | ) |
| 48 | |
| 49 | func Struct(dst interface{}) (StructValue, error) { |
| 50 | v := reflect.ValueOf(dst) |
| 51 | |
| 52 | // The destination to scan into should be a struct pointer. |
| 53 | if v.Kind() != reflect.Ptr || v.IsNil() { |
| 54 | return StructValue{}, fmt.Errorf("redis.Scan(non-pointer %T)", dst) |
| 55 | } |
| 56 | |
| 57 | v = v.Elem() |
| 58 | if v.Kind() != reflect.Struct { |
| 59 | return StructValue{}, fmt.Errorf("redis.Scan(non-struct %T)", dst) |
| 60 | } |
| 61 | |
| 62 | return StructValue{ |
| 63 | spec: globalStructMap.get(v.Type()), |
| 64 | value: v, |
| 65 | }, nil |
| 66 | } |
| 67 | |
| 68 | // Scan scans the results from a key-value Redis map result set to a destination struct. |
| 69 | // The Redis keys are matched to the struct's field with the `redis` tag. |
| 70 | func Scan(dst interface{}, keys []interface{}, vals []interface{}) error { |
| 71 | if len(keys) != len(vals) { |
| 72 | return errors.New("args should have the same number of keys and vals") |
| 73 | } |
| 74 | |
| 75 | strct, err := Struct(dst) |
| 76 | if err != nil { |
| 77 | return err |
| 78 | } |
| 79 | |
| 80 | // Iterate through the (key, value) sequence. |
| 81 | for i := 0; i < len(vals); i++ { |
| 82 | key, ok := keys[i].(string) |
| 83 | if !ok { |
| 84 | continue |
| 85 | } |
| 86 | |
| 87 | val, ok := vals[i].(string) |
| 88 | if !ok { |
| 89 | continue |
| 90 | } |
| 91 | |
| 92 | if err := strct.Scan(key, val); err != nil { |
| 93 | return err |
| 94 | } |
| 95 | } |
| 96 | |
| 97 | return nil |
| 98 | } |
| 99 | |
| 100 | func decodeBool(f reflect.Value, s string) error { |
| 101 | b, err := strconv.ParseBool(s) |
| 102 | if err != nil { |
| 103 | return err |
| 104 | } |
| 105 | f.SetBool(b) |
| 106 | return nil |
| 107 | } |
| 108 | |
| 109 | func decodeInt8(f reflect.Value, s string) error { |
| 110 | return decodeNumber(f, s, 8) |
| 111 | } |
| 112 | |
| 113 | func decodeInt16(f reflect.Value, s string) error { |
| 114 | return decodeNumber(f, s, 16) |
| 115 | } |
| 116 | |
| 117 | func decodeInt32(f reflect.Value, s string) error { |
| 118 | return decodeNumber(f, s, 32) |
| 119 | } |
| 120 | |
| 121 | func decodeInt64(f reflect.Value, s string) error { |
| 122 | return decodeNumber(f, s, 64) |
| 123 | } |
| 124 | |
| 125 | func decodeInt(f reflect.Value, s string) error { |
| 126 | return decodeNumber(f, s, 0) |
| 127 | } |
| 128 | |
| 129 | func decodeNumber(f reflect.Value, s string, bitSize int) error { |
| 130 | v, err := strconv.ParseInt(s, 10, bitSize) |
| 131 | if err != nil { |
| 132 | return err |
| 133 | } |
| 134 | f.SetInt(v) |
| 135 | return nil |
| 136 | } |
| 137 | |
| 138 | func decodeUint8(f reflect.Value, s string) error { |
| 139 | return decodeUnsignedNumber(f, s, 8) |
| 140 | } |
| 141 | |
| 142 | func decodeUint16(f reflect.Value, s string) error { |
| 143 | return decodeUnsignedNumber(f, s, 16) |
| 144 | } |
| 145 | |
| 146 | func decodeUint32(f reflect.Value, s string) error { |
| 147 | return decodeUnsignedNumber(f, s, 32) |
| 148 | } |
| 149 | |
| 150 | func decodeUint64(f reflect.Value, s string) error { |
| 151 | return decodeUnsignedNumber(f, s, 64) |
| 152 | } |
| 153 | |
| 154 | func decodeUint(f reflect.Value, s string) error { |
| 155 | return decodeUnsignedNumber(f, s, 0) |
| 156 | } |
| 157 | |
| 158 | func decodeUnsignedNumber(f reflect.Value, s string, bitSize int) error { |
| 159 | v, err := strconv.ParseUint(s, 10, bitSize) |
| 160 | if err != nil { |
| 161 | return err |
| 162 | } |
| 163 | f.SetUint(v) |
| 164 | return nil |
| 165 | } |
| 166 | |
| 167 | func decodeFloat32(f reflect.Value, s string) error { |
| 168 | v, err := strconv.ParseFloat(s, 32) |
| 169 | if err != nil { |
| 170 | return err |
| 171 | } |
| 172 | f.SetFloat(v) |
| 173 | return nil |
| 174 | } |
| 175 | |
| 176 | // although the default is float64, but we better define it. |
| 177 | func decodeFloat64(f reflect.Value, s string) error { |
| 178 | v, err := strconv.ParseFloat(s, 64) |
| 179 | if err != nil { |
| 180 | return err |
| 181 | } |
| 182 | f.SetFloat(v) |
| 183 | return nil |
| 184 | } |
| 185 | |
| 186 | func decodeString(f reflect.Value, s string) error { |
| 187 | f.SetString(s) |
| 188 | return nil |
| 189 | } |
| 190 | |
| 191 | func decodeSlice(f reflect.Value, s string) error { |
| 192 | // []byte slice ([]uint8). |
| 193 | if f.Type().Elem().Kind() == reflect.Uint8 { |
| 194 | f.SetBytes([]byte(s)) |
| 195 | } |
| 196 | return nil |
| 197 | } |
| 198 | |
| 199 | func decodeUnsupported(v reflect.Value, s string) error { |
| 200 | return fmt.Errorf("redis.Scan(unsupported %s)", v.Type()) |
| 201 | } |