var prefetchStateMachine = function()

in lib/cache.js [1144:1198]
37 lines of code
14 McCabe index (conditional complexity)

    var prefetchStateMachine = function (operation, opTargetState, cacheState, data) {
        

        // Handle cancelation
        if (!cancelStateMachine(operation, opTargetState, cacheState, data)) {

            var transition = operation.transition;

            // Handle preemption
            if (cacheState !== CACHE_STATE_PREFETCH) {
                if (cacheState === CACHE_STATE_DESTROY) {
                    if (opTargetState !== OPERATION_STATE_CANCEL) {
                        operation.cancel();
                    }
                } else if (cacheState === CACHE_STATE_IDLE) {
                    // Signal the cache that a prefetch operation is running.
                    changeState(CACHE_STATE_PREFETCH);
                }
                return true;
            }

            switch (opTargetState) {
                case OPERATION_STATE_START:
                    // Initial state of the operation.
                    if (prefetchOperations[0] === operation) {
                        transition(READ_STATE_LOCAL, operation.i);
                    }
                    break;

                case READ_STATE_DONE:
                    // State that determines if the operation can be resolved or has to
                    // continue processing.
                    // Data is expected to be the read page.
                    var pending = operation.pending;

                    if (pending > 0) {
                        pending -= Math.min(pending, data.c);
                    }

                    // Are we done, or has all the data been stored?
                    if (allDataLocal || pending === 0 || data.c < pageSize || overflowed) {
                        operation.complete();
                    } else {
                        // Continue processing the operation.
                        operation.pending = pending;
                        transition(READ_STATE_LOCAL, data.i + pageSize);
                    }
                    break;

                default:
                    return readSaveStateMachine(operation, opTargetState, cacheState, data, true);
            }
        }
        return true;
    };