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Mini Shell
Mini Shell
/**
* Module dependencies.
*/
var fmt = require('util').format;
var amp = require('amp');
/**
* Proxy methods.
*/
var methods = [
'push',
'pop',
'shift',
'unshift'
];
/**
* Expose `Message`.
*/
module.exports = Message;
/**
* Initialize an AMP message with the
* given `args` or message buffer.
*
* @param {Array|Buffer} args or blob
* @api public
*/
function Message(args) {
if (Buffer.isBuffer(args)) args = decode(args);
this.args = args || [];
}
// proxy methods
methods.forEach(function(method){
Message.prototype[method] = function(){
return this.args[method].apply(this.args, arguments);
};
});
/**
* Inspect the message.
*
* @return {String}
* @api public
*/
Message.prototype.inspect = function(){
return fmt('<Message args=%d size=%d>',
this.args.length,
this.toBuffer().length);
};
/**
* Return an encoded AMP message.
*
* @return {Buffer}
* @api public
*/
Message.prototype.toBuffer = function(){
return encode(this.args);
};
/**
* Decode `msg` and unpack all args.
*
* @param {Buffer} msg
* @return {Array}
* @api private
*/
function decode(msg) {
var args = amp.decode(msg);
for (var i = 0; i < args.length; i++) {
args[i] = unpack(args[i]);
}
return args;
}
/**
* Encode and pack all `args`.
*
* @param {Array} args
* @return {Buffer}
* @api private
*/
function encode(args) {
var tmp = new Array(args.length);
for (var i = 0; i < args.length; i++) {
tmp[i] = pack(args[i]);
}
return amp.encode(tmp);
}
/**
* Pack `arg`.
*
* @param {Mixed} arg
* @return {Buffer}
* @api private
*/
function pack(arg) {
// blob
if (Buffer.isBuffer(arg)) return arg;
// string
if ('string' == typeof arg) return new Buffer('s:' + arg);
// undefined
if (arg === undefined) arg = null;
// json
return new Buffer('j:' + JSON.stringify(arg));
}
/**
* Unpack `arg`.
*
* @param {Buffer} arg
* @return {Mixed}
* @api private
*/
function unpack(arg) {
// json
if (isJSON(arg)) return JSON.parse(arg.slice(2));
// string
if (isString(arg)) return arg.slice(2).toString();
// blob
return arg;
}
/**
* String argument.
*/
function isString(arg) {
return 115 == arg[0] && 58 == arg[1];
}
/**
* JSON argument.
*/
function isJSON(arg) {
return 106 == arg[0] && 58 == arg[1];
}
/**
* ID argument.
*/
function isId(arg) {
return 105 == arg[0] && 58 == arg[1];
}
Zerion Mini Shell 1.0