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@ethitter @westi @joshbetz @mjangda
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<?php
/*
Plugin Name: Advanced Post Caching
Description: Cache post queries.
Version: 0.2
Author: Automattic
Author URI: http://automattic.com/
*/
class Advanced_Post_Cache {
var $CACHE_GROUP_PREFIX = 'advanced_post_cache_';
// Flag for temp (within one page load) turning invalidations on and off
// @see dont_clear_advanced_post_cache()
// @see do_clear_advanced_post_cache()
// Used to prevent invalidation during new comment
var $do_flush_cache = true;
// Flag for preventing multiple invalidations in a row: clean_post_cache() calls itself recursively for post children.
var $need_to_flush_cache = true; // Currently disabled
/* Per cache-clear data */
var $cache_incr = 0; // Increments the cache group (advanced_post_cache_0, advanced_post_cache_1, ...)
var $cache_group = ''; // CACHE_GROUP_PREFIX . $cache_incr
/* Per query data */
var $cache_key = ''; // md5 of current SQL query
var $all_post_ids = false; // IDs of all posts current SQL query returns
var $cached_post_ids = array(); // subset of $all_post_ids whose posts are currently in cache
var $cached_posts = array();
var $found_posts = false; // The result of the FOUND_ROWS() query
var $cache_func = 'wp_cache_add'; // Turns to set if there seems to be inconsistencies
function __construct() {
// Specific to certain Memcached Object Cache plugins
if ( function_exists( 'wp_cache_add_group_prefix_map' ) ) {
wp_cache_add_group_prefix_map( $this->CACHE_GROUP_PREFIX, 'advanced_post_cache' );
}
$this->setup_for_blog();
add_action( 'switch_blog', array( $this, 'setup_for_blog' ), 10, 2 );
add_filter( 'posts_request', array( &$this, 'posts_request' ), 10, 2 ); // Short circuits if cached
add_filter( 'posts_results', array( &$this, 'posts_results' ), 10, 2 ); // Collates if cached, primes cache if not
add_filter( 'post_limits_request', array( &$this, 'post_limits_request' ), 999, 2 ); // Checks to see if we need to worry about found_posts
add_filter( 'found_posts_query', array( &$this, 'found_posts_query' ), 10, 2 ); // Short circuits if cached
add_filter( 'found_posts', array( &$this, 'found_posts' ), 10, 2 ); // Reads from cache if cached, primes cache if not
}
function setup_for_blog( $new_blog_id = false, $previous_blog_id = false ) {
if ( $new_blog_id && $new_blog_id == $previous_blog_id ) {
return;
}
$this->cache_incr = wp_cache_get( 'advanced_post_cache', 'cache_incrementors' ); // Get and construct current cache group name
if ( !is_numeric( $this->cache_incr ) ) {
$now = time();
wp_cache_set( 'advanced_post_cache', $now, 'cache_incrementors' );
$this->cache_incr = $now;
}
$this->cache_group = $this->CACHE_GROUP_PREFIX . $this->cache_incr;
}
/* Advanced Post Cache API */
/**
* Flushes the cache by incrementing the cache group
*/
function flush_cache() {
// Cache flushes have been disabled
if ( !$this->do_flush_cache )
return;
// Bail on post preview
if ( is_admin() && isset( $_POST['wp-preview'] ) && 'dopreview' == $_POST['wp-preview'] )
return;
// Bail on autosave
if ( defined( 'DOING_AUTOSAVE' ) && DOING_AUTOSAVE )
return;
// We already flushed once this page load, and have not put anything into the cache since.
// OTHER processes may have put something into the cache! In theory, this could cause stale caches.
// We do this since clean_post_cache() (which fires the action this method attaches to) is called RECURSIVELY for all descendants.
// if ( !$this->need_to_flush_cache )
// return;
$this->cache_incr = wp_cache_incr( 'advanced_post_cache', 1, 'cache_incrementors' );
if ( 10 < strlen( $this->cache_incr ) ) {
wp_cache_set( 'advanced_post_cache', 0, 'cache_incrementors' );
$this->cache_incr = 0;
}
$this->cache_group = $this->CACHE_GROUP_PREFIX . $this->cache_incr;
$this->need_to_flush_cache = false;
}
/* Cache Reading/Priming Functions */
/**
* Determines (by hash of SQL) if query is cached.
* If cached: Return query of needed post IDs.
* Otherwise: Returns query unchanged.
*/
function posts_request( $sql, $query ) {
global $wpdb;
if ( apply_filters( 'advanced_post_cache_skip_for_post_type', false, $query->get( 'post_type' ) ) ) {
return $sql;
}
$this->cache_key = md5( $sql ); // init
$this->all_post_ids = wp_cache_get( $this->cache_key, $this->cache_group );
if ( 'NA' !== $this->found_posts )
$this->found_posts = wp_cache_get( "{$this->cache_key}_found", $this->cache_group );
if ( $this->all_post_ids xor $this->found_posts )
$this->cache_func = 'wp_cache_set';
else
$this->cache_func = 'wp_cache_add';
$this->cached_post_ids = array(); // re-init
$this->cached_posts = array(); // re-init
// Query is cached
if ( $this->found_posts && is_array( $this->all_post_ids ) ) {
if ( function_exists( 'wp_cache_get_multi' ) ) {
$this->cached_posts = wp_cache_get_multi( array( 'posts' => $this->all_post_ids ) );
} else {
$this->cached_posts = array();
foreach ( $this->all_post_ids as $pid ) {
$this->cached_posts[] = wp_cache_get( $pid, 'posts' );
}
}
$this->cached_posts = array_filter( $this->cached_posts );
foreach ( $this->cached_posts as $post ) {
if ( !empty( $post ) )
$this->cached_post_ids[] = $post->ID;
}
$uncached_post_ids = array_diff( $this->all_post_ids, $this->cached_post_ids );
if ( $uncached_post_ids )
return "SELECT * FROM $wpdb->posts WHERE ID IN(" . join( ',', array_map( 'absint', $uncached_post_ids ) ) . ")";
return '';
}
return $sql;
}
/**
* If cached: Collates posts returned by SQL query with posts that are already cached. Orders correctly.
* Otherwise: Primes cache with data for current posts WP_Query.
*/
function posts_results( $posts, $query ) {
if ( apply_filters( 'advanced_post_cache_skip_for_post_type', false, $query->get( 'post_type' ) ) ) {
return $posts;
}
if ( $this->found_posts && is_array( $this->all_post_ids ) ) { // is cached
$collated_posts = array();
foreach ( $this->cached_posts as $post )
$posts[] = $post;
foreach ( $posts as $post ) {
$loc = array_search( $post->ID, $this->all_post_ids );
if ( is_numeric( $loc ) && -1 < $loc )
$collated_posts[$loc] = $post;
}
ksort( $collated_posts );
return array_map( 'get_post', array_values( $collated_posts ) );
}
$post_ids = array();
foreach ( (array) $posts as $post )
$post_ids[] = $post->ID;
if ( !$post_ids )
return array();
call_user_func( $this->cache_func, $this->cache_key, $post_ids, $this->cache_group );
$this->need_to_flush_cache = true;
return array_map( 'get_post', $posts );
}
/**
* If $limits is empty, WP_Query never calls the found_rows stuff, so we set $this->found_rows to 'NA'
*/
function post_limits_request( $limits, $query ) {
if ( apply_filters( 'advanced_post_cache_skip_for_post_type', false, $query->get( 'post_type' ) ) ) {
return $limits;
}
if ( empty( $limits ) || ( isset( $query->query_vars['no_found_rows'] ) && $query->query_vars['no_found_rows'] ) )
$this->found_posts = 'NA';
else
$this->found_posts = false; // re-init
return $limits;
}
/**
* If cached: Blanks SELECT FOUND_ROWS() query. This data is already stored in cache.
* Otherwise: Returns query unchanged.
*/
function found_posts_query( $sql, $query ) {
if ( apply_filters( 'advanced_post_cache_skip_for_post_type', false, $query->get( 'post_type' ) ) ) {
return $sql;
}
if ( $this->found_posts && is_array( $this->all_post_ids ) ) // is cached
return '';
return $sql;
}
/**
* If cached: Returns cached result of FOUND_ROWS() query.
* Otherwise: Returs result unchanged
*/
function found_posts( $found_posts, $query ) {
if ( apply_filters( 'advanced_post_cache_skip_for_post_type', false, $query->get( 'post_type' ) ) ) {
return $found_posts;
}
if ( $this->found_posts && is_array( $this->all_post_ids ) ) // is cached
return (int) $this->found_posts;
call_user_func( $this->cache_func, "{$this->cache_key}_found", (int) $found_posts, $this->cache_group );
$this->need_to_flush_cache = true;
return $found_posts;
}
}
global $advanced_post_cache_object;
$advanced_post_cache_object = new Advanced_Post_Cache;
function clear_advanced_post_cache() {
global $advanced_post_cache_object;
$advanced_post_cache_object->flush_cache();
}
function do_clear_advanced_post_cache() {
$GLOBALS['advanced_post_cache_object']->do_flush_cache = true;
}
function dont_clear_advanced_post_cache() {
$GLOBALS['advanced_post_cache_object']->do_flush_cache = false;
}
add_action( 'clean_term_cache', 'clear_advanced_post_cache' );
add_action( 'clean_post_cache', 'clear_advanced_post_cache' );
// Don't clear Advanced Post Cache for a new comment - temp core hack
// http://core.trac.wordpress.org/ticket/15565
add_action( 'wp_updating_comment_count', 'dont_clear_advanced_post_cache' );
add_action( 'wp_update_comment_count' , 'do_clear_advanced_post_cache' );
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