Now options may have a 'readStream' option

.gitignore

@@ -0,0 +1 @@
+node_modules

lib/filewalker.js

@@ -20,12 +20,35 @@ function Filewalker(root, options) {
   var self = this;
 
   this.matchRegExp = null;
-  
+
   this.recursive = true;
-  
+
   options = options || {};
+
+  var readStreamOptions = {
+    flags: 'r',
+    encoding: null,
+    fd: null,
+    mode: 0666,
+    autoClose: true,
+    highWaterMark: 64 * 1024
+  };
+
+  if ( ! options.readStream ) {
+    options.readStream = readStreamOptions;
+  } else {
+    // Overwrite only the specified properties
+    for ( var i in options.readStream ) {
+      readStreamOptions[ i ] = options.readStream[ i ];
+    }
+    options.readStream = readStreamOptions;
+  }
+
+  this.readStream = options.readStream;
+
+  // Copy all the options properties to this, except 'readStream'
   Object.keys(options).forEach(function(k) {
-    if(self.hasOwnProperty(k)) {
+    if( self.hasOwnProperty(k) ) {
       self[k] = options[k];
     }
   });
@@ -85,7 +108,7 @@ Filewalker.prototype._emitStream = function(p, s, fullPath) {
 
   this.open += 1;
 
-  var rs = fs.ReadStream(fullPath);
+  var rs = fs.ReadStream(fullPath, this.readStream);
 
   // retry on any error
   rs.on('error', function(err) {

test/basic-test.js

@@ -369,4 +369,25 @@ describe('Filewalker', function() {
       fw.walk();
     });
   });
+
+  describe('feature: use given readStream options', function() {
+      var myHighWaterMark = 1024*1024;
+      var fw;
+      before(function() {
+        fw = filewalker(examplesFile, { readStream: { highWaterMark: myHighWaterMark } } );
+      });
+      after(function() {
+        fw = null;
+      });      
+      it('when "stream", it should be using the given readStream option', function(done) {
+        fw.on('stream', function(rs, p, s, fullPath) {
+          assert.strictEqual( fw.readStream.highWaterMark, myHighWaterMark );
+          assert.strictEqual( fw.readStream.highWaterMark, rs._readableState.highWaterMark );
+          reallyReadTheReadStream(rs);
+        });
+        fw.on('done', done);
+        fw.walk();
+      });      
+
+  });
 });