Issue 361 - patterns.ini cleared when writing to file got interrupted

lib/filesystem/io.js

Index: lib/filesystem/io.js
===================================================================
--- a/lib/filesystem/io.js
+++ b/lib/filesystem/io.js
@@ -107,25 +107,26 @@
           op();
         }.bind(this);
 
-        executeWriteOperation(writer.truncate.bind(writer, 0), function()
+        var blob;
+
+        try
         {
-          var blob;
-          try
-          {
-            blob = new Blob([data.join(this.lineBreak) + this.lineBreak], {type: "text/plain"});
-          }
-          catch (e)
-          {
-            if (!(e instanceof TypeError))
-              throw e;
+          blob = new Blob([data.join(this.lineBreak) + this.lineBreak], {type: "text/plain"});
+        }
+        catch (e)
+        {
+          if (!(e instanceof TypeError))
+            throw e;
 
-            // Blob wasn't a constructor before Chrome 20
-            var builder = new (window.BlobBuilder || window.WebKitBlobBuilder);
-            builder.append(data.join(this.lineBreak) + this.lineBreak);
-            blob = builder.getBlob("text/plain");
-          }
-          executeWriteOperation(writer.write.bind(writer, blob), callback.bind(null, null));
-        }.bind(this));
+          // Blob wasn't a constructor before Chrome 20
+          var builder = new (window.BlobBuilder || window.WebKitBlobBuilder);
+          builder.append(data.join(this.lineBreak) + this.lineBreak);
+          blob = builder.getBlob("text/plain");
+        }
+        executeWriteOperation(writer.write.bind(writer, blob), function()
+        {
+          executeWriteOperation(writer.truncate.bind(writer, writer.position), callback.bind(null, null));
+        });
       }.bind(this), callback);
     }.bind(this), callback);
   },