667
edits
Changes
m
→Use of macros
* see http://developer.mozilla.org/en/docs/Category:XPCOM_Macros for more examples
NS_DECL_ appended with any interface name in all caps will declare all of the methods of that interface for you(nsIFoo --> NS_DECL_NSIFOO). Looking at the code above shows you how this is possible. For example, NS_DECL_NSIFOO will declare all of the methods of nsIFoo, provided that it exists and that nsIFoo.h was generated by the XPIDL compiler. Consider the following real class:
class myClass : public nsISomeClass
The declaration of nsISomeClass doesn't include any methods other than the constructor and destructor. Instead, the class uses the NS_DECL_ macro
Also note the use of NS_METHOD and NS_METHODIMP for return type signatures. All XPCOM functions are required to return a result code ('''[http://bonsai.mozilla.org/cvsblame.cgi?file=/mozilla/xpcom/base/nscore.h&rev=1.103&raw=1&mark=324-327ń nsresult'''], a integer), which indicates whether or not the function worked (e.g., NS_OK).
Next there is NS_IMPL_ISUPPORTS1. This macro implements the nsISupports interface for you, specifically the implementation of AddRef, Release, and QueryInterface for any object.
NS_IMPL_ISUPPORTS2(classname, interface1, nsISupports)
As an example, consider [http://lxrbonsai.mozilla.org/seamonkey/sourcecvsblame.cgi?file=mozilla/xpcom/io/nsBinaryStream.cpp&rev=1.32&raw=1&mark=65> 65 seamonkeymozilla/xpcom/io/nsBinaryStream.cpp]:
NS_IMPL_ISUPPORTS3(nsBinaryOutputStream, nsIObjectOutputStream, nsIBinaryOutputStream, nsIOutputStream)
