Working date rolling file stream

lib/streams/DateRollingFileStream.js

@@ -1,16 +1,89 @@
 var BaseRollingFileStream = require('./BaseRollingFileStream'),
+    format = require('../date_format'),
+    async = require('async'),
+    fs = require('fs'),
     util = require('util');
 
 module.exports = DateRollingFileStream;
 
-function DateRollingFileStream(filename, pattern, options) {
-    if (typeof(pattern) === 'object') {
+function debug(message) {
+//    console.log(message);
+}
+
+function DateRollingFileStream(filename, pattern, options, now) {
+    debug("Now is " + now);
+    if (pattern && typeof(pattern) === 'object') {
+        now = options;
         options = pattern;
         pattern = null;
     }
-    this.pattern = pattern || 'yyyy-mm-dd';
+    this.pattern = pattern || '.yyyy-MM-dd';
+    this.now = now || Date.now;
+    this.lastTimeWeWroteSomething = format.asString(this.pattern, new Date(this.now()));
+    debug("this.now is " + this.now + ", now is " + now);
 
     DateRollingFileStream.super_.call(this, filename, options);
+    this.rollBeforeWrite = true;
 }
 
 util.inherits(DateRollingFileStream, BaseRollingFileStream);
+
+DateRollingFileStream.prototype.shouldRoll = function() {
+    var lastTime = this.lastTimeWeWroteSomething,
+        thisTime = format.asString(this.pattern, new Date(this.now()));
+
+    debug("DateRollingFileStream.shouldRoll with now = " + this.now() + ", thisTime = " + thisTime + ", lastTime = " + lastTime);
+
+    this.lastTimeWeWroteSomething = thisTime;
+    this.previousTime = lastTime;
+
+    return thisTime !== lastTime;
+};
+
+DateRollingFileStream.prototype.roll = function(filename, callback) {
+    var that = this,
+        newFilename = filename + this.previousTime;
+
+    debug("Starting roll");
+    debug("Queueing up data until we've finished rolling");
+    debug("Flushing underlying stream");
+    this.flush();
+
+    async.series([
+        deleteAnyExistingFile,
+        renameTheCurrentFile,
+        openANewFile
+    ], callback);
+
+    function deleteAnyExistingFile(cb) {
+        //on windows, you can get a EEXIST error if you rename a file to an existing file
+        //so, we'll try to delete the file we're renaming to first
+        fs.unlink(newFilename, function (err) {
+            //ignore err: if we could not delete, it's most likely that it doesn't exist
+            cb();
+        });
+    }
+
+    function renameTheCurrentFile(cb) {
+        debug("Renaming the " + filename + " -> " + newFilename);
+        fs.rename(filename, newFilename, cb);
+    }
+
+    function openANewFile(cb) {
+        debug("Opening a new file");
+        fs.open(
+            filename,
+            that.options.flags,
+            that.options.mode,
+            function (err, fd) {
+                debug("opened new file");
+                var oldLogFileFD = that.fd;
+                that.fd = fd;
+                that.writable = true;
+                fs.close(oldLogFileFD, cb);
+            }
+        );
+    }
+
+
+};