Jsctypes has been introduced in Firefox 3.6 with simple C function call and only simple types: int, char, string, … But the next iteration of jsctypes that is coming in Firefox 4 is going to allow full C binding, with support of C structures and the ability to define a javascript function and give it to C library as a function pointer.
No more compilation, no more mozilla sdk download, nor XPCOM stuff, just plain javascript and only a tiny part of function and datatype declaration before doing a native binding!
But let the code talk! Here is an example that display a tray icon on windows. You can copy and paste this code in your Javascript Console in Firefox 4 beta, just do not forget to change the icon path defined in the loadimage function call.
/* simply load "ctypes" object */
Components.utils.import("resource://gre/modules/ctypes.jsm");
/* Load libraries that we are going to use */
var libuser32 = ctypes.open("user32.dll");
var libshell32 = ctypes.open("shell32.dll");
/* Here is the tedious work of declaring functions arguments types and struct attributes types */
/* In fact it's quite easy, you just have to find which precise type are using your native functions/struct */
/* but it may be hard to known, for example in windows API, which precise type is behing their "HANDLE" type ... */
/* I recommend you to find and look at python ctype binding source code because they already had done this work */
/*
HANDLE WINAPI LoadImage(
__in_opt HINSTANCE hinst,
__in LPCTSTR lpszName,
__in UINT uType,
__in int cxDesired,
__in int cyDesired,
__in UINT fuLoad
);
*/
var loadimage = libuser32.declare("LoadImageA",
ctypes.stdcall_abi,
ctypes.int,
ctypes.int,
ctypes.char.ptr,
ctypes.int,
ctypes.int,
ctypes.int,
ctypes.int);
const LR_LOADFROMFILE = 16;
const IMAGE_ICON = 1;
var notificationdata = ctypes.StructType("NOTIFICATIONDATA",
[{ cbSize : ctypes.int },
{ hWnd : ctypes.int },
{ uID : ctypes.int },
{ uFlags : ctypes.int },
{ uCallbackMessage : ctypes.int },
{ hIcon : ctypes.int },
{ szTip : ctypes.char.array(64) },
{ dwState : ctypes.int },
{ dwStateMask : ctypes.int },
{ szInfo : ctypes.char.array(256) },
{ uTimeoutOrVersion : ctypes.int },
{ szInfoTitle : ctypes.char.array(64) },
{ dwInfoFlags : ctypes.int },
{ guidItem : ctypes.int },
{ hBalloonIcon : ctypes.int }
]);
const NIF_ICON = 0x00000002;
/*
BOOL Shell_NotifyIcon(
__in DWORD dwMessage,
__in PNOTIFYICONDATA lpdata
);
*/
var notifyicon = libshell32.declare("Shell_NotifyIcon",
ctypes.stdcall_abi,
ctypes.bool,
ctypes.int,
notificationdata.ptr);
const NIM_ADD = 0x00000000;
/* And now, the "real" code that is calling C functions */
/* load our ico file */
var hIcon = loadimage(0, "c:\\default.ico", IMAGE_ICON, 16, 16, LR_LOADFROMFILE);
/* create a C struct that is defining a notification in tray */
var icon = notificationdata();
icon.cbSize = notificationdata.size;
icon.uFlags = NIF_ICON;
icon.szTip = "My Tray Icon";
icon.hIcon = hIcon;
/* Display this notification! */
notifyicon(NIM_ADD, icon.address());
We will be able to go futher and define a function callback to handle click
events on the trayicon, but there is currently a bug which cause some crashes
when using ctypes.FunctionType on windows. (ctypes.FunctionType allow to
transform a custom Javascript function to a C function pointer)
Here is related bugs, which are still in process:
- Bug 573066 - Fix ctypes stdcall closure tests
- Bug 585175 - Don’t automangle ctypes stdcall symbols for WINAPI
The first leads to crashes with FunctionType, and the second may lead to lib.declare with unfindable symbols errors when using ctypes.stdcall_abi.
You just have to click on it to get back to test
editor and have all javascript code needed to get a reference to this node,
something like this:
This
is the default status of the selector, it simply says that the current firefox
behavior is "as before", using the same global session for all tabs.
First, we create one session linked to a
personnal account. In this example I take gmail, but it can be any website :
twitter, facebook, flickr, … whatever! To do so we click on the profile
selector and get menu on the left and we click on "+ new profiles" and get the
right’s one.
Then, we do the same for one professional account:
yoono.test.
Later, we can reopen one of these sessions
directly to the homepage with the profile selector and get automatically signed
in. The "switch to" link doesn’t go to the homepage and only reload the current
tab with the selected session (very usefull for Facebook connect, sharing,
…). 
Then on Linux, 
And finally on a Mac! 
But for now, I’m going to show you all
the code needed to make this first version.
