diff options
Diffstat (limited to 'vendor/github.com/aws/smithy-go/encoding/json/decoder_util.go')
| -rw-r--r-- | vendor/github.com/aws/smithy-go/encoding/json/decoder_util.go | 139 |
1 files changed, 139 insertions, 0 deletions
diff --git a/vendor/github.com/aws/smithy-go/encoding/json/decoder_util.go b/vendor/github.com/aws/smithy-go/encoding/json/decoder_util.go new file mode 100644 index 0000000..7050c85 --- /dev/null +++ b/vendor/github.com/aws/smithy-go/encoding/json/decoder_util.go @@ -0,0 +1,139 @@ +package json + +import ( + "bytes" + "encoding/json" + "fmt" + "io" +) + +// DiscardUnknownField discards unknown fields from a decoder body. +// This function is useful while deserializing a JSON body with additional +// unknown information that should be discarded. +func DiscardUnknownField(decoder *json.Decoder) error { + // This deliberately does not share logic with CollectUnknownField, even + // though it could, because if we were to delegate to that then we'd incur + // extra allocations and general memory usage. + v, err := decoder.Token() + if err == io.EOF { + return nil + } + if err != nil { + return err + } + + if _, ok := v.(json.Delim); ok { + for decoder.More() { + err = DiscardUnknownField(decoder) + } + endToken, err := decoder.Token() + if err != nil { + return err + } + if _, ok := endToken.(json.Delim); !ok { + return fmt.Errorf("invalid JSON : expected json delimiter, found %T %v", + endToken, endToken) + } + } + + return nil +} + +// CollectUnknownField grabs the contents of unknown fields from the decoder body +// and returns them as a byte slice. This is useful for skipping unknown fields without +// completely discarding them. +func CollectUnknownField(decoder *json.Decoder) ([]byte, error) { + result, err := collectUnknownField(decoder) + if err != nil { + return nil, err + } + + buff := bytes.NewBuffer(nil) + encoder := json.NewEncoder(buff) + + if err := encoder.Encode(result); err != nil { + return nil, err + } + + return buff.Bytes(), nil +} + +func collectUnknownField(decoder *json.Decoder) (interface{}, error) { + // Grab the initial value. This could either be a concrete value like a string or a a + // delimiter. + token, err := decoder.Token() + if err == io.EOF { + return nil, nil + } + if err != nil { + return nil, err + } + + // If it's an array or object, we'll need to recurse. + delim, ok := token.(json.Delim) + if ok { + var result interface{} + if delim == '{' { + result, err = collectUnknownObject(decoder) + if err != nil { + return nil, err + } + } else { + result, err = collectUnknownArray(decoder) + if err != nil { + return nil, err + } + } + + // Discard the closing token. decoder.Token handles checking for matching delimiters + if _, err := decoder.Token(); err != nil { + return nil, err + } + return result, nil + } + + return token, nil +} + +func collectUnknownArray(decoder *json.Decoder) ([]interface{}, error) { + // We need to create an empty array here instead of a nil array, since by getting + // into this function at all we necessarily have seen a non-nil list. + array := []interface{}{} + + for decoder.More() { + value, err := collectUnknownField(decoder) + if err != nil { + return nil, err + } + array = append(array, value) + } + + return array, nil +} + +func collectUnknownObject(decoder *json.Decoder) (map[string]interface{}, error) { + object := make(map[string]interface{}) + + for decoder.More() { + key, err := collectUnknownField(decoder) + if err != nil { + return nil, err + } + + // Keys have to be strings, which is particularly important as the encoder + // won't except a map with interface{} keys + stringKey, ok := key.(string) + if !ok { + return nil, fmt.Errorf("expected string key, found %T", key) + } + + value, err := collectUnknownField(decoder) + if err != nil { + return nil, err + } + + object[stringKey] = value + } + + return object, nil +} |
