80 lines
2.0 KiB
JavaScript
80 lines
2.0 KiB
JavaScript
var fs = require('fs'),
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stream = require('stream'),
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util = require('util');
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function debug(message) {
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// console.log(message);
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}
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module.exports = BaseRollingFileStream;
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function BaseRollingFileStream(filename, options) {
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debug("In BaseRollingFileStream");
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this.filename = filename;
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this.options = options || { encoding: 'utf8', mode: 0644, flags: 'a' };
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this.currentSize = 0;
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function currentFileSize(file) {
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var fileSize = 0;
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try {
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fileSize = fs.statSync(file).size;
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} catch (e) {
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// file does not exist
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}
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return fileSize;
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}
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function throwErrorIfArgumentsAreNotValid() {
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if (!filename) {
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throw new Error("You must specify a filename");
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}
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}
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throwErrorIfArgumentsAreNotValid();
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debug("Calling BaseRollingFileStream.super");
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BaseRollingFileStream.super_.call(this);
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this.openTheStream();
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this.currentSize = currentFileSize(this.filename);
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}
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util.inherits(BaseRollingFileStream, stream.Writable);
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BaseRollingFileStream.prototype._write = function(chunk, encoding, callback) {
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var that = this;
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function writeTheChunk() {
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debug("writing the chunk to the underlying stream");
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that.currentSize += chunk.length;
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that.theStream.write(chunk, encoding, callback);
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}
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debug("in _write");
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if (this.shouldRoll()) {
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this.currentSize = 0;
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this.roll(this.filename, writeTheChunk);
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} else {
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writeTheChunk();
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}
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};
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BaseRollingFileStream.prototype.openTheStream = function(cb) {
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debug("opening the underlying stream");
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this.theStream = fs.createWriteStream(this.filename, this.options);
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if (cb) {
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this.theStream.on("open", cb);
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}
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};
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BaseRollingFileStream.prototype.closeTheStream = function(cb) {
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debug("closing the underlying stream");
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this.theStream.end(null, null, cb);
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};
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BaseRollingFileStream.prototype.shouldRoll = function() {
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return false; // default behaviour is never to roll
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};
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BaseRollingFileStream.prototype.roll = function(filename, callback) {
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callback(); // default behaviour is not to do anything
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};
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