- Patch #622048 by sun: streamline drupal_bootstrap() and expose the flow to code profilers.

includes/bootstrap.inc

@@ -782,14 +782,27 @@ function variable_del($name) {
  * from a form submission, the contents of a shopping cart, or other user-
  * specific content that should not be cached and displayed to other users.
  *
+ * @param $check_only
+ *   (optional) Set to TRUE to only return whether a previous call found a
+ *   cache entry.
+ *
  * @return
  *   The cache object, if the page was found in the cache, NULL otherwise.
  */
-function drupal_page_get_cache() {
+function drupal_page_get_cache($check_only = FALSE) {
   global $base_root;
+  static $cache_hit = FALSE;
+
+  if ($check_only) {
+    return $cache_hit;
+  }
 
   if (drupal_page_is_cacheable()) {
-    return cache_get($base_root . request_uri(), 'cache_page');
+    $cache = cache_get($base_root . request_uri(), 'cache_page');
+    if ($cache !== FALSE) {
+      $cache_hit = TRUE;
+    }
+    return $cache;
   }
 }
 
@@ -798,6 +811,7 @@ function drupal_page_get_cache() {
  *
  * @param $allow_caching
  *   Set to FALSE if you want to prevent this page to get cached.
+ *
  * @return
  *   TRUE if the current page can be cached, FALSE otherwise.
  */
@@ -1447,7 +1461,41 @@ function drupal_bootstrap($phase = NULL, $new_phase = TRUE) {
     // phase.
     while ($phases && $phase > $completed_phase && $final_phase > $completed_phase) {
       $current_phase = array_shift($phases);
-      _drupal_bootstrap($current_phase);
+      switch ($current_phase) {
+        case DRUPAL_BOOTSTRAP_CONFIGURATION:
+          _drupal_bootstrap_configuration();
+          break;
+
+        case DRUPAL_BOOTSTRAP_PAGE_CACHE:
+          _drupal_bootstrap_page_cache();
+          break;
+
+        case DRUPAL_BOOTSTRAP_DATABASE:
+          _drupal_bootstrap_database();
+          break;
+
+        case DRUPAL_BOOTSTRAP_VARIABLES:
+          _drupal_bootstrap_variables();
+          break;
+
+        case DRUPAL_BOOTSTRAP_SESSION:
+          require_once DRUPAL_ROOT . '/' . variable_get('session_inc', 'includes/session.inc');
+          drupal_session_initialize();
+          break;
+
+        case DRUPAL_BOOTSTRAP_PAGE_HEADER:
+          _drupal_bootstrap_page_header();
+          break;
+
+        case DRUPAL_BOOTSTRAP_LANGUAGE:
+          drupal_language_initialize();
+          break;
+
+        case DRUPAL_BOOTSTRAP_FULL:
+          require_once DRUPAL_ROOT . '/includes/common.inc';
+          _drupal_bootstrap_full();
+          break;
+      }
       // This function is reentrant. Only update the completed phase when the
       // current call actually resulted in a progress in the bootstrap process.
       if ($current_phase > $completed_phase) {
@@ -1459,31 +1507,22 @@ function drupal_bootstrap($phase = NULL, $new_phase = TRUE) {
 }
 
 /**
- * Return the current bootstrap phase for this Drupal process. The
+ * Bootstrap configuration: Setup script environment and load settings.php.
- * current phase is the one most recently completed by
- * drupal_bootstrap().
- *
- * @see drupal_bootstrap
  */
-function drupal_get_bootstrap_phase() {
+function _drupal_bootstrap_configuration() {
-  return drupal_bootstrap();
-}
-
-function _drupal_bootstrap($phase) {
-  global $conf, $user;
-  static $cache;
-
-  switch ($phase) {
-
-    case DRUPAL_BOOTSTRAP_CONFIGURATION:
   drupal_environment_initialize();
   // Start a page timer:
   timer_start('page');
   // Initialize the configuration, including variables from settings.php.
   drupal_settings_initialize();
-      break;
+}
+
+/**
+ * Bootstrap page cache: Try to serve a page from cache.
+ */
+function _drupal_bootstrap_page_cache() {
+  global $user;
 
-    case DRUPAL_BOOTSTRAP_PAGE_CACHE:
   // Allow specifying special cache handlers in settings.php, like
   // using memcached or files for storing cache information.
   require_once DRUPAL_ROOT . '/' . variable_get('cache_inc', 'includes/cache.inc');
@@ -1522,9 +1561,12 @@ function _drupal_bootstrap($phase) {
       exit;
     }
   }
-      break;
+}
 
-    case DRUPAL_BOOTSTRAP_DATABASE:
+/**
+ * Bootstrap database: Initialize database system and register autoload functions.
+ */
+function _drupal_bootstrap_database() {
   // The user agent header is used to pass a database prefix in the request when
   // running tests. However, for security reasons, it is imperative that we
   // validate we ourselves made the request.
@@ -1538,24 +1580,27 @@ function _drupal_bootstrap($phase) {
   // Register autoload functions so that we can access classes and interfaces.
   spl_autoload_register('drupal_autoload_class');
   spl_autoload_register('drupal_autoload_interface');
-      break;
+}
+
+/**
+ * Bootstrap variables: Load system variables and all enabled bootstrap modules.
+ */
+function _drupal_bootstrap_variables() {
+  global $conf;
 
-    case DRUPAL_BOOTSTRAP_VARIABLES:
   // Load variables from the database, but do not overwrite variables set in settings.php.
   $conf = variable_initialize(isset($conf) ? $conf : array());
   // Load bootstrap modules.
   require_once DRUPAL_ROOT . '/includes/module.inc';
   module_load_all(TRUE);
-      break;
+}
 
-    case DRUPAL_BOOTSTRAP_SESSION:
+/**
-      require_once DRUPAL_ROOT . '/' . variable_get('session_inc', 'includes/session.inc');
+ * Bootstrap page header: Invoke hook_boot(), intialize locking system, and send default HTTP headers.
-      drupal_session_initialize();
+ */
-      break;
+function _drupal_bootstrap_page_header() {
-
-    case DRUPAL_BOOTSTRAP_PAGE_HEADER:
   bootstrap_invoke_all('boot');
-      if (!$cache && drupal_page_is_cacheable()) {
+  if (!drupal_page_get_cache(TRUE) && drupal_page_is_cacheable()) {
     header('X-Drupal-Cache: MISS');
   }
 
@@ -1567,17 +1612,17 @@ function _drupal_bootstrap($phase) {
     ob_start();
     drupal_page_header();
   }
-      break;
+}
 
-    case DRUPAL_BOOTSTRAP_LANGUAGE:
+/**
-      drupal_language_initialize();
+ * Returns the current bootstrap phase for this Drupal process.
-      break;
+ *
-
+ * The current phase is the one most recently completed by drupal_bootstrap().
-    case DRUPAL_BOOTSTRAP_FULL:
+ *
-      require_once DRUPAL_ROOT . '/includes/common.inc';
+ * @see drupal_bootstrap()
-      _drupal_bootstrap_full();
+ */
-      break;
+function drupal_get_bootstrap_phase() {
-  }
+  return drupal_bootstrap();
 }
 
 /**