- Patch #251792 by pwolanin, Damien Tournoud, slantview, c960657: added a locking framework for long running operations.

5 files changed, 129 insertions, 1 deletions

diff --git a/modules/locale/locale.module b/modules/locale/locale.module
index cb37d8cbf..dcb046cdf 100644
--- a/modules/locale/locale.module
+++ b/modules/locale/locale.module
@@ -375,7 +375,7 @@ function locale($string = NULL, $context = NULL, $langcode = NULL, $reset = FALS
       if ($cache = cache_get('locale:' . $langcode, 'cache')) {
         $locale_t[$langcode] = $cache->data;
       }
-      else {
+      elseif (lock_acquire('locale_cache_' . $langcode)) {
         // Refresh database stored cache of translations for given language.
         // We only store short strings used in current version, to improve
         // performance and consume less memory.
@@ -384,6 +384,7 @@ function locale($string = NULL, $context = NULL, $langcode = NULL, $reset = FALS
           $locale_t[$langcode][$data->context][$data->source] = (empty($data->translation) ? TRUE : $data->translation);
         }
         cache_set('locale:' . $langcode, $locale_t[$langcode]);
+        lock_release('locale_cache_' . $langcode);
       }
     }
   }
diff --git a/modules/simpletest/simpletest.info b/modules/simpletest/simpletest.info
index dc3974902..9d307eb5b 100644
--- a/modules/simpletest/simpletest.info
+++ b/modules/simpletest/simpletest.info
@@ -24,6 +24,7 @@ files[] = tests/filetransfer.test
 files[] = tests/form.test
 files[] = tests/graph.test
 files[] = tests/image.test
+files[] = tests/lock.test
 files[] = tests/menu.test
 files[] = tests/module.test
 files[] = tests/registry.test
diff --git a/modules/simpletest/tests/lock.test b/modules/simpletest/tests/lock.test
new file mode 100644
index 000000000..d9fc53f75
--- /dev/null
+++ b/modules/simpletest/tests/lock.test
@@ -0,0 +1,58 @@
+<?php
+// $Id$
+
+/**
+ * Tests for the lock system.
+ */
+class LockFunctionalTest extends DrupalWebTestCase {
+
+  public static function getInfo() {
+    return array(
+      'name' => 'Locking framework tests',
+      'description' => 'Confirm locking works between two separate requests.',
+      'group' => 'System',
+    );
+  }
+
+  function setUp() {
+    parent::setUp('system_test');
+  }
+
+  /**
+   * Confirm that we can acquire and release locks in two parallel requests.
+   */
+  function testLockAcquire() {
+    $lock_acquired = 'TRUE: Lock successfully acquired in system_test_lock_acquire()';
+    $lock_not_acquired = 'FALSE: Lock not acquired in system_test_lock_acquire()';
+    $this->assertTrue(lock_acquire('system_test_lock_acquire'), t('Lock acquired by this request.'), t('Lock'));
+    $this->assertTrue(lock_acquire('system_test_lock_acquire'), t('Lock extended by this request.'), t('Lock'));
+    lock_release('system_test_lock_acquire');
+
+    // Cause another request to acquire the lock.
+    $this->drupalGet('system-test/lock-acquire');
+    $this->assertText($lock_acquired, t('Lock acquired by the other request.'), t('Lock'));
+    // The other request has finished, thus it should have released its lock.
+    $this->assertTrue(lock_acquire('system_test_lock_acquire'), t('Lock acquired by this request.'), t('Lock'));
+    // This request holds the lock, so the other request cannot acquire it.
+    $this->drupalGet('system-test/lock-acquire');
+    $this->assertText($lock_not_acquired, t('Lock not acquired by the other request.'), t('Lock'));
+    lock_release('system_test_lock_acquire');
+
+    // Try a very short timeout and lock breaking.
+    $this->assertTrue(lock_acquire('system_test_lock_acquire', 0.5), t('Lock acquired by this request.'), t('Lock'));
+    sleep(1);
+    // The other request should break our lock.
+    $this->drupalGet('system-test/lock-acquire');
+    $this->assertText($lock_acquired, t('Lock acquired by the other request, breaking our lock.'), t('Lock'));
+    // We cannot renew it, since the other thread took it.
+    $this->assertFalse(lock_acquire('system_test_lock_acquire'), t('Lock cannot be extended by this request.'), t('Lock'));
+
+    // Check the shut-down function.
+    $lock_acquired_exit = 'TRUE: Lock successfully acquired in system_test_lock_exit()';
+    $lock_not_acquired_exit = 'FALSE: Lock not acquired in system_test_lock_exit()';
+    $this->drupalGet('system-test/lock-exit');
+    $this->assertText($lock_acquired_exit, t('Lock acquired by the other request before exit.'), t('Lock'));
+    $this->assertTrue(lock_acquire('system_test_lock_exit'), t('Lock acquired by this request after the other request exits.'), t('Lock'));
+  }
+}
+
diff --git a/modules/simpletest/tests/system_test.module b/modules/simpletest/tests/system_test.module
index 3f0a1acef..90a8f28a0 100644
--- a/modules/simpletest/tests/system_test.module
+++ b/modules/simpletest/tests/system_test.module
@@ -59,6 +59,20 @@ function system_test_menu() {
     'type' => MENU_CALLBACK,
   );
 
+  $items['system-test/lock-acquire'] = array(
+    'title' => 'Lock acquire',
+    'page callback' => 'system_test_lock_acquire',
+    'access callback' => TRUE,
+    'type' => MENU_CALLBACK,
+  );
+
+  $items['system-test/lock-exit'] = array(
+    'title' => 'Lock acquire then exit',
+    'page callback' => 'system_test_lock_exit',
+    'access callback' => TRUE,
+    'type' => MENU_CALLBACK,
+  );
+
   return $items;
 }
 
@@ -185,3 +199,29 @@ function system_test_system_info_alter(&$info, $file) {
   }
 }
 
+/**
+ * Try to acquire a named lock and report the outcome.
+ */
+function system_test_lock_acquire() {
+  if (lock_acquire('system_test_lock_acquire')) {
+    lock_release('system_test_lock_acquire');
+    return 'TRUE: Lock successfully acquired in system_test_lock_acquire()';
+  }
+  else {
+    return 'FALSE: Lock not acquired in system_test_lock_acquire()';
+  }
+}
+
+/**
+ * Try to acquire a specific lock, and then exit.
+ */
+function system_test_lock_exit() {
+  if (lock_acquire('system_test_lock_exit', 900)) {
+    echo 'TRUE: Lock successfully acquired in system_test_lock_exit()';
+    // The shut-down function should release the lock.
+    exit();
+  }
+  else {
+    return 'FALSE: Lock not acquired in system_test_lock_exit()';
+  }
+}
diff --git a/modules/system/system.install b/modules/system/system.install
index 3ff1c5905..83a0f268b 100644
--- a/modules/system/system.install
+++ b/modules/system/system.install
@@ -1265,6 +1265,34 @@ function system_schema() {
     'primary key' => array('filename'),
   );
 
+  $schema['semaphore'] = array(
+    'description' => 'Table for holding semaphores, locks, flags, etc. that cannot be stored as Drupal variables since they must not be cached.',
+    'fields' => array(
+      'name' => array(
+        'description' => 'Primary Key: Unique name.',
+        'type' => 'varchar',
+        'length' => 255,
+        'not null' => TRUE,
+        'default' => ''
+      ),
+      'value' => array(
+        'description' => 'A value for the semaphore.',
+        'type' => 'varchar',
+        'length' => 255,
+        'not null' => TRUE,
+        'default' => ''
+      ),
+      'expire' => array(
+        'description' => 'A Unix timestamp with microseconds indicating when the semaphore should expire.',
+        'type' => 'float',
+        'size' => 'big',
+        'not null' => TRUE
+      ),
+    ),
+    'indexes' => array('value' => array('value')),
+    'primary key' => array('name'),
+  );
+
   $schema['sessions'] = array(
     'description' => "Drupal's session handlers read and write into the sessions table. Each record represents a user session, either anonymous or authenticated.",
     'fields' => array(