static void read_trace_flags()

in rts/RtsFlags.c [2019:2092]

• 53 lines of code
• 11 McCabe index (conditional complexity)

static void read_trace_flags(const char *arg)
{
    const char *c;
    bool enabled = true;
    /* Syntax for tracing flags currently looks like:
     *
     *   -l    To turn on eventlog tracing with default trace classes
     *   -lx   Turn on class 'x' (for some class listed below)
     *   -l-x  Turn off class 'x'
     *   -la   Turn on all classes
     *   -l-a  Turn off all classes
     *
     * This lets users say things like:
     *   -la-p    "all but sparks"
     *   -l-ap    "only sparks"
     */

    /* Start by turning on the default tracing flags.
     *
     * Currently this is all the trace classes, except full-detail sparks.
     * Similarly, in future we might default to slightly less verbose
     * scheduler or GC tracing.
     */
    RtsFlags.TraceFlags.scheduler      = true;
    RtsFlags.TraceFlags.gc             = true;
    RtsFlags.TraceFlags.sparks_sampled = true;
    RtsFlags.TraceFlags.user           = true;

    for (c  = arg; *c != '\0'; c++) {
        switch(*c) {
        case '\0':
            break;
        case '-':
            enabled = false;
            break;
        case 'a':
            RtsFlags.TraceFlags.scheduler      = enabled;
            RtsFlags.TraceFlags.gc             = enabled;
            RtsFlags.TraceFlags.sparks_sampled = enabled;
            RtsFlags.TraceFlags.sparks_full    = enabled;
            RtsFlags.TraceFlags.user           = enabled;
            enabled = true;
            break;

        case 's':
            RtsFlags.TraceFlags.scheduler = enabled;
            enabled = true;
            break;
        case 'p':
            RtsFlags.TraceFlags.sparks_sampled = enabled;
            enabled = true;
            break;
        case 'f':
            RtsFlags.TraceFlags.sparks_full = enabled;
            enabled = true;
            break;
        case 't':
            RtsFlags.TraceFlags.timestamp = enabled;
            enabled = true;
            break;
        case 'g':
            RtsFlags.TraceFlags.gc        = enabled;
            enabled = true;
            break;
        case 'u':
            RtsFlags.TraceFlags.user      = enabled;
            enabled = true;
            break;
        default:
            errorBelch("unknown trace option: %c",*c);
            break;
        }
    }
}