高分悬赏！！！android按键分发问题

Question

WindowManagerService.java (base\services\java\com\android\server)中的按键分发线程 private void process() 中有这段代码（问题在代码中）
else if (lastKey != null) //这个lastkey是什么意思，找不到解释，是消息队列中的上一个按键吗？
{
                        curTime = SystemClock.uptimeMillis();//获取的什么时间                        // Timeout occurred while key was down.  If it is at or
                        // past the key repeat time, dispatch the repeat.
                        if (DEBUG_INPUT) Slog.v(
                            TAG, "Key timeout: repeat=" + nextKeyTime
                            + ", now=" + curTime);
                        if (curTime < nextKeyTime) //什么意思
                        {
                            continue;
                        }                        lastKeyTime = nextKeyTime;
                        nextKeyTime = nextKeyTime + KEY_REPEAT_DELAY;
                        keyRepeatCount++;
                        if (DEBUG_INPUT) Slog.v(
                            TAG, "Key repeat: count=" + keyRepeatCount
                            + ", next @ " + nextKeyTime);
                        KeyEvent newEvent;
                        if (downTime != 0 && (downTime
                                + ViewConfiguration.getLongPressTimeout())
                                <= curTime) //该分支怎么理解
                              {
                            newEvent = KeyEvent.changeTimeRepeat(lastKey,
                                    curTime, keyRepeatCount,
                                    lastKey.getFlags() | KeyEvent.FLAG_LONG_PRESS);
                            downTime = 0;
                        } else {
                            newEvent = KeyEvent.changeTimeRepeat(lastKey,
                                    curTime, keyRepeatCount);
                        }

                        // dispatchKey(newEvent, 0, 0);//按键事件分发给谁了？
最好能解释一下QueuedEvent和KeyEvent不胜感激！！！问题有点多