Allow checksum to be called without changing the context of the this object

lib/rsync.js

@@ -216,10 +216,10 @@ function roll(data, checksums, chunkSize) {
 }
 
 // RSync function to calculate checksums
-function checksum (path, size, callback) {
+function checksum (fs, path, size, callback) {
   var cache = {};
 
-  this.readFile(path, function (err, data) {
+  fs.readFile(path, function (err, data) {
     if (!err) {
       // cache file
       cache[path] = data;
@@ -441,7 +441,7 @@ rsync.checksums = function(fs, path, srcList, options, callback) {
           nodeChecksums.push(nodeChecksum);
           callback();
         } else {
-          checksum.call(fs, absPath, options.size, function(err, checksums) {
+          checksum(fs, absPath, options.size, function(err, checksums) {
             if(err) {
               return callback(err);
             }
@@ -455,7 +455,7 @@ rsync.checksums = function(fs, path, srcList, options, callback) {
         }
       });
     } else {
-      checksum.call(fs, absPath, options.size, function(err, checksums) {
+      checksum(fs, absPath, options.size, function(err, checksums) {
         if(err) {
           return callback(err);
         }
@@ -967,7 +967,7 @@ rsync.pathChecksums = function(fs, paths, chunkSize, callback) {
       }
 
       // Calculate checksums for file or symbolic links
-      checksum.call(fs, path, chunkSize, function(err, chksum) {
+      checksum(fs, path, chunkSize, function(err, chksum) {
         if(err) {
           return callback(err);
         }
@@ -1065,7 +1065,7 @@ rsync.compareContents = function(fs, checksums, chunkSize, callback) {
       }
 
       // Compare checksums for two files/symbolic links
-      checksum.call(fs, path, chunkSize, function(err, checksum) {
+      checksum(fs, path, chunkSize, function(err, checksum) {
         if(err) {
           return callback(err);
         }