#315801 by Rob Loach, Grugnoh2, mfer and dmitrig01: Add a hook_js_alter() to modify JavaScript being printed to the page.

4 files changed, 71 insertions, 24 deletions

diff --git a/includes/common.inc b/includes/common.inc
index 76eac625b..ad04138c7 100644
--- a/includes/common.inc
+++ b/includes/common.inc
@@ -2232,15 +2232,8 @@ function drupal_add_js($data = NULL, $options = NULL, $reset = FALSE) {
   else {
     $options = array();
   }
-  $options += array(
-    'type' => 'file',
-    'weight' => JS_DEFAULT,
-    'scope' => 'header',
-    'cache' => TRUE,
-    'defer' => FALSE,
-    'preprocess' => TRUE,
-    'data' => $data,
-  );
+  $options += drupal_js_defaults($data);
+
   // Preprocess can only be set if caching is enabled.
   $options['preprocess'] = $options['cache'] ? $options['preprocess'] : FALSE;
 
@@ -2305,6 +2298,26 @@ function drupal_add_js($data = NULL, $options = NULL, $reset = FALSE) {
 }
 
 /**
+ * Constructs an array of the defaults that are used for JavaScript items.
+ *
+ * @param $data
+ *   (optional) The default data parameter for the JavaScript item array.
+ * @see drupal_get_js()
+ * @see drupal_add_js()
+ */
+function drupal_js_defaults($data = NULL) {
+  return array(
+    'type' => 'file',
+    'weight' => JS_DEFAULT,
+    'scope' => 'header',
+    'cache' => TRUE,
+    'defer' => FALSE,
+    'preprocess' => TRUE,
+    'data' => $data,
+  );
+}
+
+/**
  * Returns a themed presentation of all JavaScript code for the current page.
  *
  * References to JavaScript files are placed in a certain order: first, all
@@ -2312,6 +2325,13 @@ function drupal_add_js($data = NULL, $options = NULL, $reset = FALSE) {
  * are added to the page. Then, all settings are output, followed by 'inline'
  * JavaScript code. If running update.php, all preprocessing is disabled.
  *
+ * Note that hook_js_alter(&$javascript) is called during this function call
+ * to allow alterations of the JavaScript during its presentation. Calls to
+ * drupal_add_js() from hook_js_alter() will not be added to the output
+ * presentation. The correct way to add JavaScript during hook_js_alter()
+ * is to add another element to the $javascript array, deriving from
+ * drupal_js_defaults(). See locale_js_alter() for an example of this.
+ *
  * @param $scope
  *   (optional) The scope for which the JavaScript rules should be returned.
  *   Defaults to 'header'.
@@ -2321,11 +2341,10 @@ function drupal_add_js($data = NULL, $options = NULL, $reset = FALSE) {
  * @return
  *   All JavaScript code segments and includes for the scope as HTML tags.
  * @see drupal_add_js()
+ * @see locale_js_alter()
+ * @see drupal_js_defaults()
  */
 function drupal_get_js($scope = 'header', $javascript = NULL) {
-  if ((!defined('MAINTENANCE_MODE') || MAINTENANCE_MODE != 'update') && function_exists('locale_update_js_files')) {
-    locale_update_js_files();
-  }
   if (!isset($javascript)) {
     $javascript = drupal_add_js();
   }
@@ -2333,6 +2352,9 @@ function drupal_get_js($scope = 'header', $javascript = NULL) {
     return '';
   }
 
+  // Allow modules to alter the JavaScript.
+  drupal_alter('js', $javascript);
+
   // Filter out elements of the given scope.
   $items = array();
   foreach ($javascript as $item) {
diff --git a/modules/locale/locale.module b/modules/locale/locale.module
index 15629d3b8..99fe894f3 100644
--- a/modules/locale/locale.module
+++ b/modules/locale/locale.module
@@ -505,21 +505,18 @@ function locale_system_update($components) {
 }
 
 /**
- * Update JavaScript translation file, if required, and add it to the page.
+ * Implementation of hook_js_alter().
  *
  * This function checks all JavaScript files currently added via drupal_add_js()
  * and invokes parsing if they have not yet been parsed for Drupal.t()
  * and Drupal.formatPlural() calls. Also refreshes the JavaScript translation
  * file if necessary, and adds it to the page.
  */
-function locale_update_js_files() {
+function locale_js_alter(&$javascript) {
   global $language;
 
   $dir = file_create_path(variable_get('locale_js_directory', 'languages'));
   $parsed = variable_get('javascript_parsed', array());
-
-  // Get an array of all the JavaScript added so far.
-  $javascript = drupal_add_js();
   $files = $new_files = FALSE;
 
   foreach ($javascript as $item) {
@@ -563,7 +560,9 @@ function locale_update_js_files() {
 
   // Add the translation JavaScript file to the page.
   if ($files && !empty($language->javascript)) {
-    drupal_add_js($dir . '/' . $language->language . '_' . $language->javascript . '.js');
+    // Add the translation JavaScript file to the page.
+    $file = $dir . '/' . $language->language . '_' . $language->javascript . '.js';
+    $javascript[$file] = drupal_js_defaults($file);
   }
 }
 
diff --git a/modules/simpletest/simpletest.module b/modules/simpletest/simpletest.module
index 71225ff5c..9d1431065 100644
--- a/modules/simpletest/simpletest.module
+++ b/modules/simpletest/simpletest.module
@@ -210,10 +210,7 @@ function simpletest_test_form() {
 
 function theme_simpletest_test_table($table) {
   drupal_add_css(drupal_get_path('module', 'simpletest') . '/simpletest.css');
-
-  // Since SimpleTest is a special use case for the table select, stick the
-  // SimpleTest JavaScript above the table select.
-  drupal_add_js(drupal_get_path('module', 'simpletest') . '/simpletest.js', array('weight' => JS_DEFAULT - 1));
+  drupal_add_js(drupal_get_path('module', 'simpletest') . '/simpletest.js');
 
   // Create header for test selection table.
   $header = array(
@@ -301,6 +298,18 @@ function theme_simpletest_test_table($table) {
   }
 }
 
+/**
+ * Implementation of hook_js_alter().
+ */
+function simpletest_js_alter(&$javascript) {
+  // Since SimpleTest is a special use case for the table select, stick the
+  // SimpleTest JavaScript above the table select.
+  $simpletest = drupal_get_path('module', 'simpletest') . '/simpletest.js';
+  if (array_key_exists($simpletest, $javascript) && array_key_exists('misc/tableselect.js', $javascript)) {
+    $javascript[$simpletest]['weight'] = $javascript['misc/tableselect.js']['weight'] - 1;
+  }
+}
+
 function theme_simpletest_result_summary($form, $text = NULL) {
   return '<div class="simpletest-'. ($form['#ok'] ? 'pass' : 'fail') .'">' . _simpletest_format_summary_line($form) . '</div>';
 }
diff --git a/modules/simpletest/tests/common.test b/modules/simpletest/tests/common.test
index 01fe73546..ec04641e1 100644
--- a/modules/simpletest/tests/common.test
+++ b/modules/simpletest/tests/common.test
@@ -376,8 +376,8 @@ class JavaScriptTestCase extends DrupalWebTestCase {
    * Implementation of setUp().
    */
   function setUp() {
-    // Enable locale in test environment.
-    parent::setUp('locale');
+    // Enable Locale and SimpleTest in the test environment.
+    parent::setUp('locale', 'simpletest');
 
     // Disable preprocessing
     $this->preprocess_js = variable_get('preprocess_js', 0);
@@ -488,6 +488,23 @@ class JavaScriptTestCase extends DrupalWebTestCase {
     $javascript = drupal_get_js();
     $this->assertTrue(strpos($javascript, 'misc/collapse.js') < strpos($javascript, 'misc/jquery.js'), t('Rendering a JavaScript file above jQuery.'));
   }
+
+  /**
+   * Test altering a JavaScript's weight via hook_js_alter().
+   *
+   * @see simpletest_js_alter()
+   */
+  function testAlter() {
+    // Add both tableselect.js and simpletest.js, with a larger weight on SimpleTest.
+    drupal_add_js('misc/tableselect.js');
+    drupal_add_js(drupal_get_path('module', 'simpletest') . '/simpletest.js', array('weight' => JS_THEME));
+
+    // Render the JavaScript, testing if simpletest.js was altered to be before
+    // tableselect.js. See simpletest_js_alter() to see where this alteration
+    // takes place.
+    $javascript = drupal_get_js();
+    $this->assertTrue(strpos($javascript, 'simpletest.js') < strpos($javascript, 'misc/tableselect.js'), t('Altering JavaScript weight through the alter hook.'));
+  }
 }
 
 /**