Problems wp_insert_post and save_posts filter

Question

I'm having an issue with using wp_insert_post. I'm adding the ability for a post of one type to create a post of another type with the first post as the post parent. I was testing out a few things using the save_posts filter. I created a function that simply creates a post and then hooked that function to the save_posts filter. The problem I'm having is that it is adding posts exponentially to my mySQL table. The longer I let it run before I put a freeze on the server, the more posts get added. Is there a better way of doing this?

Example code:

public function save() {
    $my_child = array(
                'post_title' => $this->_child_type,
                'post_content' => "test content",
                'post_status' => 'publish',
                'post_type' => "video",
                'post_parent'=> 55
              );
    $nindex = wp_insert_post($my_child);
}
add_action('save_post', array(&$this, 'save'));

Answer 1

you can check what post type is calling the 'save_post' action try:

public function save() {
global $post;
  if (!$post->post_type = 'video'){
    $my_child = array(
                'post_title' => $this->_child_type,
                'post_content' => "test content",
                'post_status' => 'publish',
                'post_type' => "video",
                'post_parent'=> 55
              );
    $nindex = wp_insert_post($my_child);
  }
}
add_action('save_post', array(&$this, 'save'));

Answer 2

It might be because of revisions - if you've got revisions enabled, then this post suggests the save happens twice on purpose - once for the revision, and once for the actual post. Answer in that post (checking for type='revision') seems like the best solution.

Answer 3

Thanks to @BAInternet for his solution. The problem it seems is that because I'm creating a post, the save function gets called twice, so the number of posts increases exponentially. The solution that I came up with is:

public function save() {
    global $post;
    global $flag;
    //Following code makes sure it doesn't get executed twice
    if($flag ==0) $flag =1;  
    else return;
    //Next to temporarily disable this filter
    remove_action('save_post', array(&$this, __FUNCTION__));
    $my_child = array(
                'post_title' => $this->_child_type,
                'post_content' => "test content",
                'post_status' => 'publish',
                'post_type' => "video",
                'post_parent'=> 55
              );
    $nindex = wp_insert_post($my_child);
    }
    //restore save
    add_action('save_post', array(&$this, __FUNCTION__));
}
add_action('save_post', array(&$this, 'save'));