Subj : Re: Missing the getProperty/setProperty mark with strings
To   : Sterling Bates <sblistserv@bigbangco.com>
From : Brendan Eich <brendan@meer.net>
Date : Sat Oct 25 2003 06:56 pm

Sterling Bates wrote:
> Here's some more info:
> 
> It looks like the jsval has no JSVAL_* markers.  The error is actually
> occuring when converting the jsval to an object (in the js_ValueToString
> function, line 2640-2646).  If I call JS_ValueToObject from my code then I
> get the same error.
> 
> I've tried both of these lines to create the JSString:
> 
> Result := jsval(JS_NewString(FContext,PChar(str),Length(str)));
> Result := jsval(StringToJSString(str));


Casting to a jsval is wrong (if that's what jsval(...) does).  You need 
to set the right tag in the low order 3 bits, as STRING_TO_JSVAL does.


> (The |str| variable is a direct reference to the Delphi object's private
> field FValue.)
> 
> -> function StringToJSString:
> 
> function StringToJSString(const str: String): PJSString;
> begin
>   New(Result);
>   Result^.length :=
> MultiByteToWideChar(0,0,PChar(str),Length(str),Result^.chars,0);
>   GetMem(Result^.chars,Result^.length);
> 
> MultiByteToWideChar(0,0,PChar(str),Length(str),Result^.chars,Result^.length)
> ;
> end;
> 

You can't New(Result), the GC must allocate all JSString structs.

/be

.