drupal_process_form 的大致流程是怎么样的 ？

函数原型

function drupal_process_form($form_id, &$form, &$form_state) {
//--
}

1 初始化 $form_state['values']

$form_state['values'] = array();

2 把$form赋值给一个变量, 然后生成新的$form
form builder 函数主要以下作用
a 给每个表单元素加上必须的属性值
b 吧用户输入的值放到#value上
c, 调用每个表单元素的#process handler
d, 把用户输入的值放到$form_state['values']下面

  $unprocessed_form = $form;
  $form = form_builder($form_id, $form, $form_state);

3 如果有用户输入 要验证之

 if ($form_state['process_input']) {
    drupal_validate_form($form_id, $form, $form_state);
}

4 如果没有错误 要重置form id static ?

if (!form_get_errors()) {
      // In case of errors, do not break HTML IDs of other forms.
      drupal_static_reset('drupal_html_id');
    }

5 运行submit handler

    if ($form_state['submitted'] && !form_get_errors() && !$form_state['rebuild']) {
      // Execute form submit handlers.
      form_execute_handlers('submit', $form, $form_state);
}

6 生成form cache

 if (!$form_state['rebuild'] && $form_state['cache'] && empty($form_state['no_cache'])) {
    form_set_cache($form['#build_id'], $unprocessed_form, $form_state);
  }

-- 这个函数很复杂  真的不懂