XPConnect Chrome Object Wrappers: Difference between revisions

XPConnect Chrome Object Wrappers (view source)

579 bytes removed , 16 October 2009

removed __callableByContent__ property, since we're not enforcing it anymore

874

edits

@@ Line 29: / Line 29: @@
    /* Do something here that requires chrome privileges. */
 }
-foo.__callableByContent__ = true;
 var sandbox = Cu.Sandbox("http://www.mozilla.org");
@@ Line 37: / Line 36: @@
 In the above example, <tt>foo()</tt> is wrapped by a COW when accessed by sandboxed code executed via <tt>Components.utils.evalInSandbox()</tt>.  The object <tt>{bar: 5}</tt> is wrapped in an <tt>XPCSafeJSObjectWrapper</tt> before being passed into <tt>foo()</tt>.
-The metadata attached to <tt>foo()</tt>, <tt>__callableByContent__</tt>, is used to explicitly declare that the function its attached to can be called from content.  This is necessary for security purposes; if a function that's only ever intended to be called from trusted code ever accidentally "falls into the wrong hands", we don't want untrusted code to be able to exploit it.
-If a function without <tt>__callableByContent__</tt> is called from content, a JS <tt>Error</tt> is raised with the text "function is not callable from content".
 === COWing Objects ===