Re: libseed-list js extensions for native modules

[Jonatan Liljedahl <lijon kymatica com>]

Doesn't work here, but now something else is strange (first try to get 
sandbox failed):

> imports.sandbox.Context.prototype.foo = function() { print("test") };
function () { print("test"); }
> c = new imports.sandbox.Context
TypeError Result of expression 'imports.sandbox' [undefined] is not an 
object.
> c = new imports.sandbox.Context
[object Context]
> c.foo()
TypeError Result of expression 'c.foo' [undefined] is not a function.
>


Alan Knowles wrote:
> Did I miss something - this works perfectly..
>
>
> GLib = imports.gi.GLib;
>
> imports.sandbox.Context.prototype.eval_file = function(fn) { 
>         var  script = {}; 
>         print("load " + fn);
>         GLib.file_get_contents(fn,script); 
>         return this.eval(script.contents); 
> };
>
> c = new imports.sandbox.Context;
> c.eval_file("test.js");
>
> #output>>>
> load test.js
>
> ** (seed:3644): CRITICAL **: Line 10 in /tmp/seedtest.js: GFileError Failed to open file 'test.js': No such file or directory
>
> Regards
> Alan
>
>
>
>  --- On 29/Jun/2010, Jonatan Liljedahl wrote: 
> > > This should be made to work - It's probably going to take a bit of
> >  > working out how to support it...
> >
> > I'm trying to understand how this works, am I right that native modules 
> > create their classes with seed_create_class() (JSClassCreate()), while 
> > the Gir importer sets up an object with a 'prototype' property "by hand"?
> >
> >  From the JSC API docs:
> >
> > "Standard JavaScript practice calls for storing function objects in 
> > prototypes, so they can be shared. The default JSClass created by 
> > JSClassCreate follows this idiom, instantiating objects with a shared, 
> > automatically generating prototype containing the class's function 
> > objects. The kJSClassAttributeNoAutomaticPrototype attribute specifies 
> > that a JSClass should not automatically generate such a prototype."
> >
> > So, the question is why the prototype is not writable and if it can be 
> > made to be that. I tried this hackish function on the constructor but it 
> > didn't work:
> >
> > gboolean
> > seed_make_extendable (JSContextRef ctx, JSObjectRef object)
> > {
> >    JSStringRef jname = JSStringCreateWithUTF8CString ("prototype");
> >    JSValueRef exception = NULL;
> >    JSValueRef proto = JSObjectGetPrototype(ctx, object);
> >    if (proto)
> >      {
> >        JSObjectSetProperty (ctx, (JSObjectRef) object, jname, proto,
> >        kJSPropertyAttributeDontEnum|kJSPropertyAttributeDontDelete,
> > 			   &exception);
> >      }
> >
> >    JSStringRelease (jname);
> >    return TRUE;
> > }
> >
> > Once JSClassCreate has made the prototype, it seems to be fixed and 
> > read-only.
> >
> > Perhaps one should create classes more "manually" like the Gir importer 
> > does instead of using JSClassCreate()?
> >
> > > Looking through the code, it's either we have to explicitly overlay
> > > the prototype properties in the constructor, or we set the
> > > parent_class of Context to a standard object..
> > parent_class can only be a JSClassRef, and it says it should be NULL for 
> > the normal Object class, which I guess it should be. Seems like 
> > JavaScriptCore has classic inherited OOP internally, and that 
> > parent_class has nothing to do with prototype. (but that all objects has 
> > Object as parent_class)
> >
> > I'm not sure I understand what you mean by overlay the prototype 
> > properties..
> >
> > /Jonatan
> >
> > > Regarsd Alan
> > >
> > > --- On 21/Jun/2010, Jonatan Liljedahl wrote:
> > > > Also, it should work to add methods to SomeClass.prototype in
> > > > native modules. Currently it does not:
> > > >
> > > > imports.sandbox.Context.prototype.eval_file = function(fn) { var
> > > > script = {}; GLib.file_get_contents(fn,script); return
> > > > this.eval(script.contents); };
> > > >
> > > > c = new imports.sandbox.Context; c.eval_file(foobar);
> > > >
> > > > TypeError Result of expression 'ctx.eval_file' [undefined] is not a
> > > >  function.
> > > >
> > > > It does work for GI modules, as seen in extensions/Gtk.js
> > > >
> > > > /Jonatan
> > > >
> > > > Jonatan Liljedahl wrote:
> > > > > The gi_importer tries to import extensions/name.js by evaluating
> > > > >  "imports.extensions.name". It would be nice if this also worked
> > > > > for native modules, I imagine it to be quite common that you
> > > > > write a module with core parts in C and some high-level stuff in
> > > > > js.
> > > > >
> > > > > The question is, how should this be handled regarding searchpaths
> > > > > etc?
> > > > >
> > > > > If your module is installed in /usr/local/lib/seed, then you
> > > > > probably installed the extension js in
> > > > > /usr/local/share/seed/extensions, and imports.extensions would be
> > > > > the right thing.
> > > > >
> > > > > But what happens if your module is installed somewhere else? It
> > > > > should probably start with the same dir as the native module,
> > > > > then go on with imports.searchPath, and if the file is found call
> > > > >  seed_importer_handle_file() on it..
> > > > >
> > > > > BTW, what happens if you have 'extensions' folder in more than
> > > > > one search path? will extensions.foo search for 'foo' in all of
> > > > > those or only the first match for 'extensions'? Just doing a
> > > > > 'imports.extensions' will of course create only one dir_importer
> > > > > for that folder, hiding possible 'extensions' folders later in
> > > > > the searchpath. I don't know if this is a good thing...
> > > > >
> > > > > /Jonatan _______________________________________________ 
> > > > > libseed-list mailing list libseed-list gnome org 
> > > > > http://mail.gnome.org/mailman/listinfo/libseed-list
> > > > _______________________________________________ libseed-list
> > > > mailing list libseed-list gnome org 
> > > > http://mail.gnome.org/mailman/listinfo/libseed-list
> > > _______________________________________________ libseed-list mailing
> > > list libseed-list gnome org 
> > > http://mail.gnome.org/mailman/listinfo/libseed-list