Paul St-Denis & Michael Lau
Short Description
XPCOM stands for Cross Platform Component Object Model. XPCOM is a framework for developing cross platform software.
Detailed Discussion
XPCOM is a framework for developing cross platform software that can be written in C, C++, JavaScript with extensions for Perl and Python. It supports any platform with a C++ compiler.
You can access the XPCOM component through the web or any Mozilla application (similar to the idea of accessing web services).
Some of the tools needed for development are:
- a C++ compiler
- a Perl interpreter
- some GNU tools
XPCOM provides the following features for cross platform development:
- Component management
- File abstraction
- Object message passing
- Memory management
Application that want to access Mozilla XPCOM libraries can use an XPCOM layer called XPConnect.
External Links
Examples
nsFileInputStream on LXR Sample code for XPCOM component
77 class nsFileInputStream : public nsFileStream,
78 public nsIFileInputStream,
79 public nsILineInputStream
80 {
81 public:
82 NS_DECL_ISUPPORTS_INHERITED
83 NS_DECL_NSIINPUTSTREAM
84 NS_DECL_NSIFILEINPUTSTREAM
85 NS_DECL_NSILINEINPUTSTREAM
86
87 // Overrided from nsFileStream
88 NS_IMETHOD Seek(PRInt32 aWhence, PRInt64 aOffset);
89
90 nsFileInputStream() : nsFileStream()
91 {
92 mLineBuffer = nsnull;
93 mBehaviorFlags = 0;
94 }
95 virtual ~nsFileInputStream()
96 {
97 Close();
98 }
...
135 nsresult Reopen() { return Open(mFile, mIOFlags, mPerm); }
136 };
Sample use of XPCOM component
var fstream = Components.classes["@mozilla.org/network/file-input-stream;1"]
.createInstance(Components.interfaces.nsIFileInputStream);