diffusion/src/node_modules/data/primitive/primitive-datatype.js

Diffusion JavaScript client

var AbstractDataType = require('data/abstract-datatype');
var BytesImpl = require('data/bytes-impl');
var JSONImpl = require('data/json/json-impl');

var Encoder = require('cbor/encoder');
var Decoder = require('cbor/decoder');

var encoder = new Encoder();

var NULL_CBOR = new BytesImpl(new Buffer([0xf6]));

module.exports = function(name, valueClass, serialise, withBinaryDelta, cborTypePredicate) {
    function vToC(value) {
        serialise(value, encoder);
        return new BytesImpl(encoder.flush());
    }

    function cToV(bytes) {
        if (NULL_CBOR.equals(bytes)) {
            return null;
        }

        var decoder = new Decoder(bytes.$buffer, bytes.$offset, bytes.$length);

        return decoder.nextValueExpecting(cborTypePredicate);
    }

    AbstractDataType.call(this, name, valueClass, BytesImpl, vToC, cToV, [JSONImpl], withBinaryDelta);

    this.writeValue = function(value) {
        if (value === null || value === undefined) {
            return NULL_CBOR.asBuffer();
        } else {
            serialise(value, encoder);
            return encoder.flush();
        }
    };

    this.validate = function() {
        // No-op. This data type validates on read.
    };

    this.from = function(value) {
        if (value.$buffer) {
            return value;
        } else {
            return vToC(value);
        }
    };
};