1 package encoding

     2 

     3 import (

     4 	"sync"

     5 )

     6 

     7 // Encoder encodes the contents of v into a byte representation.

     8 // It's primarily used for encoding a map[string]interface{} into a file format.

     9 type Encoder interface {

    10 	Encode(v map[string]interface{}) ([]byte, error)

    11 }

    12 

    13 const (

    14 	// ErrEncoderNotFound is returned when there is no encoder registered for a format.

    15 	ErrEncoderNotFound = encodingError("encoder not found for this format")

    16 

    17 	// ErrEncoderFormatAlreadyRegistered is returned when an encoder is already registered for a format.

    18 	ErrEncoderFormatAlreadyRegistered = encodingError("encoder already registered for this format")

    19 )

    20 

    21 // EncoderRegistry can choose an appropriate Encoder based on the provided format.

    22 type EncoderRegistry struct {

    23 	encoders map[string]Encoder

    24 

    25 	mu sync.RWMutex

    26 }

    27 

    28 // NewEncoderRegistry returns a new, initialized EncoderRegistry.

    29 func NewEncoderRegistry() *EncoderRegistry {

    30 	return &EncoderRegistry{

    31 		encoders: make(map[string]Encoder),

    32 	}

    33 }

    34 

    35 // RegisterEncoder registers an Encoder for a format.

    36 // Registering a Encoder for an already existing format is not supported.

    37 func (e *EncoderRegistry) RegisterEncoder(format string, enc Encoder) error {

    38 	e.mu.Lock()

    39 	defer e.mu.Unlock()

    40 

    41 	if _, ok := e.encoders[format]; ok {

    42 		return ErrEncoderFormatAlreadyRegistered

    43 	}

    44 

    45 	e.encoders[format] = enc

    46 

    47 	return nil

    48 }

    49 

    50 func (e *EncoderRegistry) Encode(format string, v map[string]interface{}) ([]byte, error) {

    51 	e.mu.RLock()

    52 	encoder, ok := e.encoders[format]

    53 	e.mu.RUnlock()

    54 

    55 	if !ok {

    56 		return nil, ErrEncoderNotFound

    57 	}

    58 

    59 	return encoder.Encode(v)

    60 }