Debugger: Difference between revisions

Debugger (view source)

Revision as of 22:35, 16 November 2011

387 bytes added , 16 November 2011

→‎Accessor Properties of the Debugger.Frame Prototype Object: Clarify behavior when there are several Debugger.Frame instances with onPop handlers for a given frame.

Jimb

Confirmed users

497

edits

@@ Line 329: / Line 329: @@
 Calls to frames' <code>onPop</code> handlers are cross-compartment, intra-thread calls: an <code>onPop</code> function must be in the debugger's compartment (and thus calls to it take place in the debugger's compartment), and the call takes place in the thread to which the frame belongs.
-When SpiderMonkey calls an <code>onPop</code> handler for a frame that is throwing an exception or being terminated, and the handler returns <code>undefined</code>, then SpiderMonkey proceeds with the exception or termination. The <code>undefined</code> resumption value leaves the throwing and termination process undisturbed.
+When a debugger handler function forces a frame to complete early, by returning a <code>{ return:... }</code>, <code>{ throw:... }</code>, or <code>null</code> resumption value, SpiderMonkey calls the frame's <code>onPop</code> handler, if any. The completion value passed in this case reflects the resumption value that caused the frame to complete.
-When a debugger handler method forces a frame to complete early, by returning a <code>{ return:... }</code>, <code>{ throw:... }</code>, or <code>null</code> resumption value, SpiderMonkey calls the frame's <code>onPop</code> handler, if any. The completion value passed in this case reflects the resumption value that caused the frame to complete.
+When SpiderMonkey calls an <code>onPop</code> handler for a frame that is throwing an exception or being terminated, and the handler returns <code>undefined</code>, then SpiderMonkey proceeds with the exception or termination. That is, an <code>undefined</code> resumption value leaves the frame's throwing and termination process undisturbed.
+If there are several <code>Debugger.Frame</code> instances for a given stack frame with <code>onPop</code> handlers set (this can occur when several <code>Debugger</code> instances are debugging the same debuggee), their handlers are run in an unspecified order. The resumption value each handler returns establishes the completion value reported to the next handler.
 When a generator frame yields a value, SpiderMonkey calls its <code>Debugger.Frame</code> instance's <code>onPop</code> handler, if present, passing a <code>yield</code> resumption value; however, the <code>Debugger.Frame</code> instance remains live.