func V()

in klog.go [1413:1445]

• 19 lines of code
• 5 McCabe index (conditional complexity)

func V(level Level) Verbose {
	// This function tries hard to be cheap unless there's work to do.
	// The fast path is two atomic loads and compares.

	// Here is a cheap but safe test to see if V logging is enabled globally.
	if logging.verbosity.get() >= level {
		return newVerbose(level, true)
	}

	// It's off globally but vmodule may still be set.
	// Here is another cheap but safe test to see if vmodule is enabled.
	if atomic.LoadInt32(&logging.filterLength) > 0 {
		// Now we need a proper lock to use the logging structure. The pcs field
		// is shared so we must lock before accessing it. This is fairly expensive,
		// but if V logging is enabled we're slow anyway.
		logging.mu.Lock()
		defer logging.mu.Unlock()
		if runtime.Callers(2, logging.pcs[:]) == 0 {
			return newVerbose(level, false)
		}
		// runtime.Callers returns "return PCs", but we want
		// to look up the symbolic information for the call,
		// so subtract 1 from the PC. runtime.CallersFrames
		// would be cleaner, but allocates.
		pc := logging.pcs[0] - 1
		v, ok := logging.vmap[pc]
		if !ok {
			v = logging.setV(pc)
		}
		return newVerbose(level, v >= level)
	}
	return newVerbose(level, false)
}