XPCOM

Welcome to the XPCOM page. This area is intended to be a central clearinghouse for information related to XPCOM.

General

• Creating XPCOM Components written by Doug Turner and Ian Oeschger that introduces XPCOM and illustrates how to create XPCOM components for Gecko-based applications.
• An introduction to XPCOM on IBM's website by Rick Parrish.
• Presentation: Introduction To XPCOM, Alec Flett (Feb 4, 2002)
• Presentation: The XPCOM Library, Alec Flett (Feb 11, 2002)
• Standalone XPCOM : Document on building xpcom standalone.
• Information on the built in support for detecting memory leaks.

Rules and guidelines for writing new code

• IDL Interface Rules - Guidelines for writing interfaces. Requirements for freezing.
• Rules we break lists and comments on xpcom rules being broken in our codebase

Smart Pointers and Ownership

• Some COM Ownership Guidelines gives a brief set of guidelines to help you build a supportable ownership model.
• nsCOMPtr User Manual describes a `smart-pointer' class for XPCOM.
• The nsCOMPtr homepage. has even more on nsCOMPtr
• nsIWeakReference User Manual describes one implementation of a safe, non-dangling, non-owning pointer you can use with XPCOM.

Manuals and Guides

• Strings - The mozilla string guide
• Hashtables - The mozilla hashtable guide
• Arrays - The mozilla array guide
• Generic Factories - don't write factory code yourself
• A Reference Implementation of QueryInterface shows one good way to implement QueryInterface().
• nsISupport Proxies describes how to use thread-crossing XPCOM proxies.
• General Overview of nsIClassInfo infrastructure
• Use the Console Service to log script errors and other user-visible messages.
• XPCOM Docs Style guide

Technotes

• Statement on binary compatibility of XPCOM interfaces across compiler versions.

XPIDL, XPConnect, and friends

• Roadmap for XPCOM, XPConnect, XPTCall, and XPIDL describes how they all fit together
• XPConnect describes how XPCOM based classes can be accessed through JavaScript.
• XPIDL is the XP Interface Description Language used to specify XPCOM interface classes
• XPIDL syntax
• XPIDL Author's guide
• xptcall is a library that supports invoking methods on arbitrary xpcom objects and implementing classes whose objects can impersonate an xpcom interface
• porting status lists the currently supported platforms. There are currently many platforms that we need help on.
• porting guide describes the assembly code that is needed to implement xptcall
• Type Library Format describe the type libraries (.xpt files) that are binary representations of XPCOM interfaces
• Tools for Typelibs - xpt_dump dumps the information in a typelib to the screen and xpt_link merges typelib files

Soon to be removed

• Modularization Techniques describes XPCOM and how to use it.

See Also

• Essential COM by Don Box hardcopy book that explains the rationale behind COM's design
• C++ portability guide general guidelines for writing portable code