イケてない 行処理 #Node.js

each-line.js

'use strict';

function onData (chunk) {
    var chunks = chunk.split(this.spliter);
    var i = 0, last = chunks.length - 1;
    for (; i < last; i++) {
        this.rs.emit('line', chunks[i], this.lines++);
    }
    this.buf = chunks[last];
}
function onEnd () {
    this.buf && this.rs.emit('line', this.buf, this.lines);
    this.buf = '';
}

function createReadLine (readableStream, option) {
    option = (typeof option === 'object' && option !== null) ? option : {};
    if (! readableStream) readableStream = process.stdin;
    if (typeof readableStream === 'string')
        readableStream = require('fs').createReadStream(readableStream, option);
    if (! readableStream.readable)
        throw Error('"readableStream" is not "readable"');
    if (! option.encoding) readableStream.setEncoding('utf8');
    var that = {
        rs: readableStream
      , buf: ''
      , lines: 0
      , spliter: '\n'
    };
    readableStream.on('data', onData.bind(that));
    readableStream.on('end',   onEnd.bind(that));
    readableStream.on('close', function () { that = undefined; });
    return readableStream;
}

module.exports.createReadLine= createReadLine;
module.exports.eachline = function (file, onLine, option) {
    var readStream = createReadLine(file, option);
    readStream.on('line', onLine);
    readStream.on('end', readStream.destroy.bind(readStream));
    return readStream;
};

filter.js

var createReadLine = require('./each-line').createReadLine;

var inputTxt  = './video/list.txt';
var outputTxt = './video/list.mp4.txt';

var ws = require('fs').createWriteStream(outputTxt);
var rs = createLineStream(inputTxt);

rs.on('line', function (line, i) {
    if (! /\.mp4/.test(line)) return;
    (ws.write(line + '\n') === false) && rs.pause();
});

ws.on('drain', function () {
    rs.resume();
});

test_createReadLine.js

var sample_text    = __dirname + '/sample.txt';
var createReadLine = require('./each-line').createReadLine;
var reader         = createReadLine(sample_text);

reader.on('open', function () {
    console.log('OPEN');
});
reader.on('line', function (line, i) {
    console.log('%d: %s', i, line);
});

reader.on('end', function () {
    console.log('END>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>');
});

test_eachline.js

/*
 *  ショートカット的な
 */

var sample_text = __dirname + '/sample.txt';
var eachine     = require('./each-line').eachline;

eachline(sample_text, function (line, i) {
    console.log('%d: %s', i, line);
});

test_http.js

var createReadLine = require('./each-line').createReadLine;
var http = require('http');

var url = 'http://friendfeed.com/ishiduca';
http.get( url, function (res) {
    createReadLine(res);
    res.on('line', function (line, i) {
        console.log('%d: %s', i, line);
    });
});

test_process_stdin.js

var util = require('util');
var createReadLine = require('./each-line').createReadLine;

var rs = createReadLine(process.stdin);
rs.on('line', function (line) {
    /^\.exit/.test(line) && process.exit(0);
    util.log(line);
});

rs.resume();