Patch Maker -- Mozilla Hacking & Patching Made Easy

Mike Angelo -- 6 October 2001 (c)

The Mozilla Organization's newest toy for Mozilla hacking is Patch Maker. It let's almost anyone familiar with XUL, JS, or CSS create patches to the Mozilla user interface – without having to deal with CVS (Concurrent Versions System), source code, C++, and/or compiling.

Patch Maker makes it easier to write and to submit Mozilla user interface (UI) patches. It was written by Mozilla developer Gervase Markham primarily for people who are not in to, or up to, dealing with CVS and compiling. Even people that are up to snuff skill-wise might not have sufficient computer resources to work with the Mozilla CVS and compiling Mozilla source code.

The impetus for creating Patch Maker seems to lie in the fact that Mozilla bugs are raging out of control. So the Mozilla developers are hoping to get more bug-fixing help from the Mozilla and Open Source communities by making it easier for people to write and submit bug-fix patches.

XUL (pronounced zuul) is Mozilla implementation of XML that is used to describe the interactive Web-like page faces of Mozilla-based applications. Think of XUL as the Mozilla developers' name for an XML-based language used to describe the UI (User Interface). Creating a Mozilla skin or UI is mostly a matter of hacking the XUL, XML, CSS, JS and so forth that define the chrome and skin, and/or redoing the graphic images and widgets they use.

To be more precise, however, XUL is not exactly XML. A standard XML parser cannot interpret XUL. That is why you cannot display XUL as a Web page with Internet Explorer 5, Netscape 4.x, or other non-Mozilla-based browsers. Mozilla-based browsers have a special parser that can interpret XUL.

Here is how it works. The Mozilla browser suite is built on top of the underlying Mozilla application programming framework, which is written in C++. For the most part, the Mozilla browser-suite user-interface employs XUL, JS, and CSS. Patch Maker is a Perl script that let's you modify the user interface XUL, JS, or CSS and try your modification(s) without having to download, compile, or recompile the source code -- and without having to deal with CVS.

More About the Mozilla Application Programming Framework

Mozilla-based Web-browser suites, including the navigator, e-mail, news, and composer components, all are applications built to run upon the underlying Mozilla application programming framework. So what you see when you run such Mozilla-based Web-browser suites essentially are interactive Web-like pages defined and controlled by the XUL, JS, and CSS code, which is interpreted at run time.

What you see when you open Mozilla or Netscape 6 (NS6) browser suites is not the Mozilla or NS6 program itself. What you see essentially is an interactive Web page generated by Mozilla and its Gecko layout engine.

Web page is an oversimplification. The Mozilla Web-browser face is similar to a Web page in that it is laid out by Mozilla's Gecko engine much as the Gecko engine lays out a Web page. Mozilla-the-browser is a combination of text, images, widgets and so forth laid out by Gecko to form an interactive user interface. That interactive user interface is very much similar to a Web page. Something we will call a Web-like page here.

Downloading & Using Patch Maker

Patch Maker is limited to the XUL, JS, and CSS code that runs on top of the underlying Mozilla application programming framework, It will not let you create patches for the underlying Mozilla framework.

You can download the Patch Maker script from the Mozilla Organization Web site. You also should read the Patch Maker Web page on the Mozilla Organization Web site. Links for the Patch Maker script and Web page are in the Resources Section at the end of this article.

Patch Maker is designed primarily for Linux. However, according to the PageMaker Web site, you should be able to use Page Maker with Windows if you also download ActivePerl and Cygwin.

If you would like to hack the Mozilla or Netscape browser suites without using Patch Maker, please check our Mozilla-skinning articles, MozillaQuest the Series: Building Your Own Mozilla-Based Web Browser .

For more information about Mozilla the organization, Mozilla the application programming framework, and Mozilla the Web browser suite, please see the series, Mozilla--A Lizard for All Seasons. (Please check the Resources Section at the end of this article for links.)