Passing objects between a Javascript-based XPCOM component and its client
XPCOM IDL allows you to pass parameters of certain types only (e.g., string, integer), in addition to objects with XPCOM interfaces (e.g., nsISupports). In order to pass anything else (e.g., a Javascript array, a Java object) from the client of a Javascript-based XPCOM component into the component, you need to wrap the object to be passed in another XPCOM object implemented using Javascript:
function WrapperClass(object) {
this.wrappedJSObject = this;
this.object = object;
}
WrapperClass.prototype = {
QueryInterface : function(iid) {
if (!iid.equals(Components.interfaces.nsISupports)) {
throw Components.results.NS_ERROR_NO_INTERFACE;
}
return this;
}
}
Now you can call the first XPCOM component passing in any kind of object by wrapping it first:
theComponent.foo(new WrapperClass(theObject))
And inside foo(), the wrapped object can be retrieved as follows:
foo : function(arg) {
var theActualObject = arg.wrappedJSObject.object;
}
In the interface definition of theComponent (in your IDL file), you need to declare that foo() takes an nsISupports parameter.
function WrapperClass(object) {
this.wrappedJSObject = this;
this.object = object;
}
WrapperClass.prototype = {
QueryInterface : function(iid) {
if (!iid.equals(Components.interfaces.nsISupports)) {
throw Components.results.NS_ERROR_NO_INTERFACE;
}
return this;
}
}
Now you can call the first XPCOM component passing in any kind of object by wrapping it first:
theComponent.foo(new WrapperClass(theObject))
And inside foo(), the wrapped object can be retrieved as follows:
foo : function(arg) {
var theActualObject = arg.wrappedJSObject.object;
}
In the interface definition of theComponent (in your IDL file), you need to declare that foo() takes an nsISupports parameter.
posted by David Huynh at
11:00 AM
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1 comments
