decoder.go

Documentation: github.com/spf13/viper/internal/encoding

     1  package encoding
     2  
     3  import (
     4  	"sync"
     5  )
     6  
     7  // Decoder decodes the contents of b into v.
     8  // It's primarily used for decoding contents of a file into a map[string]any.
     9  type Decoder interface {
    10  	Decode(b []byte, v map[string]any) error
    11  }
    12  
    13  const (
    14  	// ErrDecoderNotFound is returned when there is no decoder registered for a format.
    15  	ErrDecoderNotFound = encodingError("decoder not found for this format")
    16  
    17  	// ErrDecoderFormatAlreadyRegistered is returned when an decoder is already registered for a format.
    18  	ErrDecoderFormatAlreadyRegistered = encodingError("decoder already registered for this format")
    19  )
    20  
    21  // DecoderRegistry can choose an appropriate Decoder based on the provided format.
    22  type DecoderRegistry struct {
    23  	decoders map[string]Decoder
    24  
    25  	mu sync.RWMutex
    26  }
    27  
    28  // NewDecoderRegistry returns a new, initialized DecoderRegistry.
    29  func NewDecoderRegistry() *DecoderRegistry {
    30  	return &DecoderRegistry{
    31  		decoders: make(map[string]Decoder),
    32  	}
    33  }
    34  
    35  // RegisterDecoder registers a Decoder for a format.
    36  // Registering a Decoder for an already existing format is not supported.
    37  func (e *DecoderRegistry) RegisterDecoder(format string, enc Decoder) error {
    38  	e.mu.Lock()
    39  	defer e.mu.Unlock()
    40  
    41  	if _, ok := e.decoders[format]; ok {
    42  		return ErrDecoderFormatAlreadyRegistered
    43  	}
    44  
    45  	e.decoders[format] = enc
    46  
    47  	return nil
    48  }
    49  
    50  // Decode calls the underlying Decoder based on the format.
    51  func (e *DecoderRegistry) Decode(format string, b []byte, v map[string]any) error {
    52  	e.mu.RLock()
    53  	decoder, ok := e.decoders[format]
    54  	e.mu.RUnlock()
    55  
    56  	if !ok {
    57  		return ErrDecoderNotFound
    58  	}
    59  
    60  	return decoder.Decode(b, v)
    61  }
    62
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