BaseRollingFileStream.js
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"use strict";
var fs = require('fs')
, stream
, debug = require('../debug')('BaseRollingFileStream')
, util = require('util')
, semver = require('semver');
if (semver.satisfies(process.version, '>=0.10.0')) {
stream = require('stream');
} else {
stream = require('readable-stream');
}
module.exports = BaseRollingFileStream;
function BaseRollingFileStream(filename, options) {
debug("In BaseRollingFileStream");
this.filename = filename;
this.options = options || {};
this.options.encoding = this.options.encoding || 'utf8';
this.options.mode = this.options.mode || parseInt('0644', 8);
this.options.flags = this.options.flags || 'a';
this.currentSize = 0;
function currentFileSize(file) {
var fileSize = 0;
try {
fileSize = fs.statSync(file).size;
} catch (e) {
// file does not exist
}
return fileSize;
}
function throwErrorIfArgumentsAreNotValid() {
if (!filename) {
throw new Error("You must specify a filename");
}
}
throwErrorIfArgumentsAreNotValid();
debug("Calling BaseRollingFileStream.super");
BaseRollingFileStream.super_.call(this);
this.openTheStream();
this.currentSize = currentFileSize(this.filename);
}
util.inherits(BaseRollingFileStream, stream.Writable);
BaseRollingFileStream.prototype._write = function(chunk, encoding, callback) {
var that = this;
function writeTheChunk() {
debug("writing the chunk to the underlying stream");
that.currentSize += chunk.length;
try {
that.theStream.write(chunk, encoding, callback);
}
catch (err){
debug(err);
callback();
}
}
debug("in _write");
if (this.shouldRoll()) {
this.currentSize = 0;
this.roll(this.filename, writeTheChunk);
} else {
writeTheChunk();
}
};
BaseRollingFileStream.prototype.openTheStream = function(cb) {
debug("opening the underlying stream");
this.theStream = fs.createWriteStream(this.filename, this.options);
if (cb) {
this.theStream.on("open", cb);
}
};
BaseRollingFileStream.prototype.closeTheStream = function(cb) {
debug("closing the underlying stream");
this.theStream.end(cb);
};
BaseRollingFileStream.prototype.shouldRoll = function() {
return false; // default behaviour is never to roll
};
BaseRollingFileStream.prototype.roll = function(filename, callback) {
callback(); // default behaviour is not to do anything
};