node.js的hello world项目。
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/**
* Module dependencies.
*/
var tty = require('tty');
var util = require('util');
/**
* This is the Node.js implementation of `debug()`.
*
* Expose `debug()` as the module.
*/
exports = module.exports = require('./debug');
exports.init = init;
exports.log = log;
exports.formatArgs = formatArgs;
exports.save = save;
exports.load = load;
exports.useColors = useColors;
/**
* Colors.
*/
exports.colors = [6, 2, 3, 4, 5, 1];
/**
* Build up the default `inspectOpts` object from the environment variables.
*
* $ DEBUG_COLORS=no DEBUG_DEPTH=10 DEBUG_SHOW_HIDDEN=enabled node script.js
*/
exports.inspectOpts = Object.keys(process.env).filter(function (key) {
return /^debug_/i.test(key);
}).reduce(function (obj, key) {
// camel-case
var prop = key
.substring(6)
.toLowerCase()
.replace(/_([a-z])/g, function (_, k) { return k.toUpperCase() });
// coerce string value into JS value
var val = process.env[key];
if (/^(yes|on|true|enabled)$/i.test(val)) val = true;
else if (/^(no|off|false|disabled)$/i.test(val)) val = false;
else if (val === 'null') val = null;
else val = Number(val);
obj[prop] = val;
return obj;
}, {});
/**
* The file descriptor to write the `debug()` calls to.
* Set the `DEBUG_FD` env variable to override with another value. i.e.:
*
* $ DEBUG_FD=3 node script.js 3>debug.log
*/
var fd = parseInt(process.env.DEBUG_FD, 10) || 2;
if (1 !== fd && 2 !== fd) {
util.deprecate(function(){}, 'except for stderr(2) and stdout(1), any other usage of DEBUG_FD is deprecated. Override debug.log if you want to use a different log function (https://git.io/debug_fd)')()
}
var stream = 1 === fd ? process.stdout :
2 === fd ? process.stderr :
createWritableStdioStream(fd);
/**
* Is stdout a TTY? Colored output is enabled when `true`.
*/
function useColors() {
return 'colors' in exports.inspectOpts
? Boolean(exports.inspectOpts.colors)
: tty.isatty(fd);
}
/**
* Map %o to `util.inspect()`, all on a single line.
*/
exports.formatters.o = function(v) {
this.inspectOpts.colors = this.useColors;
return util.inspect(v, this.inspectOpts)
.split('\n').map(function(str) {
return str.trim()
}).join(' ');
};
/**
* Map %o to `util.inspect()`, allowing multiple lines if needed.
*/
exports.formatters.O = function(v) {
this.inspectOpts.colors = this.useColors;
return util.inspect(v, this.inspectOpts);
};
/**
* Adds ANSI color escape codes if enabled.
*
* @api public
*/
function formatArgs(args) {
var name = this.namespace;
var useColors = this.useColors;
if (useColors) {
var c = this.color;
var prefix = ' \u001b[3' + c + ';1m' + name + ' ' + '\u001b[0m';
args[0] = prefix + args[0].split('\n').join('\n' + prefix);
args.push('\u001b[3' + c + 'm+' + exports.humanize(this.diff) + '\u001b[0m');
} else {
args[0] = new Date().toUTCString()
+ ' ' + name + ' ' + args[0];
}
}
/**
* Invokes `util.format()` with the specified arguments and writes to `stream`.
*/
function log() {
return stream.write(util.format.apply(util, arguments) + '\n');
}
/**
* Save `namespaces`.
*
* @param {String} namespaces
* @api private
*/
function save(namespaces) {
if (null == namespaces) {
// If you set a process.env field to null or undefined, it gets cast to the
// string 'null' or 'undefined'. Just delete instead.
delete process.env.DEBUG;
} else {
process.env.DEBUG = namespaces;
}
}
/**
* Load `namespaces`.
*
* @return {String} returns the previously persisted debug modes
* @api private
*/
function load() {
return process.env.DEBUG;
}
/**
* Copied from `node/src/node.js`.
*
* XXX: It's lame that node doesn't expose this API out-of-the-box. It also
* relies on the undocumented `tty_wrap.guessHandleType()` which is also lame.
*/
function createWritableStdioStream (fd) {
var stream;
var tty_wrap = process.binding('tty_wrap');
// Note stream._type is used for test-module-load-list.js
switch (tty_wrap.guessHandleType(fd)) {
case 'TTY':
stream = new tty.WriteStream(fd);
stream._type = 'tty';
// Hack to have stream not keep the event loop alive.
// See https://github.com/joyent/node/issues/1726
if (stream._handle && stream._handle.unref) {
stream._handle.unref();
}
break;
case 'FILE':
var fs = require('fs');
stream = new fs.SyncWriteStream(fd, { autoClose: false });
stream._type = 'fs';
break;
case 'PIPE':
case 'TCP':
var net = require('net');
stream = new net.Socket({
fd: fd,
readable: false,
writable: true
});
// FIXME Should probably have an option in net.Socket to create a
// stream from an existing fd which is writable only. But for now
// we'll just add this hack and set the `readable` member to false.
// Test: ./node test/fixtures/echo.js < /etc/passwd
stream.readable = false;
stream.read = null;
stream._type = 'pipe';
// FIXME Hack to have stream not keep the event loop alive.
// See https://github.com/joyent/node/issues/1726
if (stream._handle && stream._handle.unref) {
stream._handle.unref();
}
break;
default:
// Probably an error on in uv_guess_handle()
throw new Error('Implement me. Unknown stream file type!');
}
// For supporting legacy API we put the FD here.
stream.fd = fd;
stream._isStdio = true;
return stream;
}
/**
* Init logic for `debug` instances.
*
* Create a new `inspectOpts` object in case `useColors` is set
* differently for a particular `debug` instance.
*/
function init (debug) {
debug.inspectOpts = {};
var keys = Object.keys(exports.inspectOpts);
for (var i = 0; i < keys.length; i++) {
debug.inspectOpts[keys[i]] = exports.inspectOpts[keys[i]];
}
}
/**
* Enable namespaces listed in `process.env.DEBUG` initially.
*/
exports.enable(load());