Subj : Rhino line counting
To   : netscape.public.mozilla.jseng
From : rickr_mc@lycos.com (Rick Romero)
Date : Wed Sep 17 2003 08:15 am

I'm trying to use the line counting functionality in Rhino. I know
about the setInstructionObserverThreshold, and how to extend the
Context in order to trap these events. I believe, though, that there
may be a bug in the current source. Check out Interpreter.java:2132-38

    case TokenStream.CALL : {
        if (instructionThreshold != 0) {
            instructionCount += INVOCATION_COST;
            cx.instructionCount = instructionCount;
            instructionCount = -1;
        }
        cx.instructionCount = instructionCount;

Note that after this code is executed, (cx.instructionCount == -1). It
appears that this last line is incorrect. It essentially resets the
instructionCount.

On a related note, does anyone have any idea what the intention here
was? This switch case, TokenStream.NEW and TokenStream.CALLSPECIAL all
have the same sort of thing happening with the INVOCATION_COST. Anyone
out there able to explain the rationale here? I haven't spent too much
time trying to figure out the programmer's intent, and would
appreciate it if someone in the know could provide some insight into
this section of code.

Thanks,

Rick Romero

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