cache.inc

<?php


/**
 * @file
 * Load Views' data so that it knows what is available to build queries from.
 */

/**
 * Fetch Views' data from the cache.
 *
 * @param string $table
 * @param bool $move
 *   Under certain circumstances it makes sense to not get the moved table, but
 *   the old one. One example is views_get_handler.
 * @param bool $reset
 */
function _views_fetch_data($table = NULL, $move = TRUE, $reset = FALSE) {
    $cache =& drupal_static(__FUNCTION__ . '_cache');
    $recursion_protection =& drupal_static(__FUNCTION__ . '_recursion_protected');
    $fully_loaded =& drupal_static(__FUNCTION__ . '_fully_loaded');
    if ($reset) {
        $cache = NULL;
        $fully_loaded = FALSE;
    }
    if ($table) {
        if (!isset($cache[$table])) {
            $cid = 'views_data:' . $table;
            if ($data = views_cache_get($cid, TRUE)) {
                $cache[$table] = $data->data;
            }
            else {
                if (!$fully_loaded) {
                    // Try to load the full views cache.
                    if ($data = views_cache_get('views_data', TRUE)) {
                        $cache = $data->data;
                    }
                    else {
                        // No cache entry, rebuild.
                        $cache = _views_fetch_data_build();
                    }
                    $fully_loaded = TRUE;
                }
                // Write back a cache for this table.
                if (isset($cache[$table])) {
                    views_cache_set($cid, $cache[$table], TRUE);
                }
                else {
                    // If there is still no information about that table, it is missing.
                    // Write an empty array to avoid repeated rebuilds.
                    views_cache_set($cid, array(), TRUE);
                }
            }
        }
        if (isset($cache[$table])) {
            if (isset($cache[$table]['moved to']) && $move) {
                $moved_table = $cache[$table]['moved to'];
                if (!empty($recursion_protection[$table])) {
                    // Recursion detected!
                    return NULL;
                }
                $recursion_protection[$table] = TRUE;
                $data = _views_fetch_data($moved_table);
                $recursion_protection = array();
                return $data;
            }
            return $cache[$table];
        }
    }
    else {
        if (!$fully_loaded) {
            if ($data = views_cache_get('views_data', TRUE)) {
                $cache = $data->data;
            }
            else {
                // No cache entry, rebuild.
                $cache = _views_fetch_data_build();
            }
            $fully_loaded = TRUE;
        }
        return $cache;
    }
    // Return an empty array if there is no match.
    return array();
}

/**
 * Build and set the views data cache if empty.
 */
function _views_fetch_data_build() {
    views_include_handlers();
    $cache = module_invoke_all('views_data');
    foreach (module_implements('views_data_alter') as $module) {
        $function = $module . '_views_data_alter';
        $function($cache);
    }
    _views_data_process_entity_types($cache);
    // Keep a record with all data.
    views_cache_set('views_data', $cache, TRUE);
    return $cache;
}

/**
 * Links tables having an 'entity type' specified to the respective generic
 * entity-type tables.
 */
function _views_data_process_entity_types(&$data) {
    foreach ($data as $table_name => $table_info) {
        // Add in a join from the entity-table if an entity-type is given.
        if (!empty($table_info['table']['entity type'])) {
            $entity_table = 'views_entity_' . $table_info['table']['entity type'];
            $data[$entity_table]['table']['join'][$table_name] = array(
                'left_table' => $table_name,
            );
            $data[$entity_table]['table']['entity type'] = $table_info['table']['entity type'];
            // Copy over the default table group if we have none yet.
            if (!empty($table_info['table']['group']) && empty($data[$entity_table]['table']['group'])) {
                $data[$entity_table]['table']['group'] = $table_info['table']['group'];
            }
        }
    }
}

/**
 * Fetch the plugin data from cache.
 */
function _views_fetch_plugin_data($type = NULL, $plugin = NULL, $reset = FALSE) {
    static $cache = NULL;
    if (!isset($cache) || $reset) {
        // Load necessary code once.
        if (!isset($cache)) {
            views_include('plugins');
            views_include_handlers();
        }
        // Because plugin data contains translated strings, and as such can be
        // expensive to build, the results are cached per language.
        global $language;
        $cache_key = 'views:plugin_data:' . $language->language;
        if (!$reset) {
            if ($cache = cache_get($cache_key)) {
                $cache = $cache->data;
            }
        }
        // If not available in the cache, build it and cache it.
        if (!$cache || $reset) {
            $cache = views_discover_plugins();
            cache_set($cache_key, $cache);
        }
    }
    if (!$type && !$plugin) {
        return $cache;
    }
    elseif (!$plugin) {
        // Not in the if above so the else below won't run.
        if (isset($cache[$type])) {
            return $cache[$type];
        }
    }
    elseif (isset($cache[$type][$plugin])) {
        return $cache[$type][$plugin];
    }
    // Return an empty array if there is no match.
    return array();
}

/**
 * Set a cached item in the views cache.
 *
 * This is just a convenience wrapper around cache_set().
 *
 * @param string $cid
 *   The cache ID of the data to store.
 * @param mixed $data
 *   The data to store in the cache. Complex data types will be automatically
 *   serialized before insertion. Strings will be stored as plain text and not
 *   serialized.
 * @param bool $use_language
 *   If TRUE, the data will be cached specific to the currently active language.
 */
function views_cache_set($cid, $data, $use_language = FALSE) {
    global $language;
    if (variable_get('views_skip_cache', FALSE)) {
        return;
    }
    if ($use_language) {
        $cid .= ':' . $language->language;
    }
    cache_set($cid, $data, 'cache_views');
}

/**
 * Return data from the persistent views cache.
 *
 * This is just a convenience wrapper around cache_get().
 *
 * @param int $cid
 *   The cache ID of the data to retrieve.
 * @param bool $use_language
 *   If TRUE, the data will be requested specific to the currently active
 *   language.
 *
 * @return stdClass|bool
 *   The cache or FALSE on failure.
 */
function views_cache_get($cid, $use_language = FALSE) {
    global $language;
    if (variable_get('views_skip_cache', FALSE)) {
        return FALSE;
    }
    if ($use_language) {
        $cid .= ':' . $language->language;
    }
    return cache_get($cid, 'cache_views');
}