Standard XPCOM components

There are a number of components provided in the standard implementation of XPCOM; these are as follows.

nsCategoryManager
The XPCOM Category Manager.
nsDirectoryService
The XPCOM Directory Service. This service returns the locations of "well known" directories in an OS-independent manner. For instance, it can give you the path of the system's temporary directory, desktop directory, current working directory, and so on.
nsLocalFile
A component implementing nsILocalFile.
nsObserverService
The XPCOM Observer Service.
nsScriptableInputStream
A component implementing nsIScriptableInputStream.