CRM-13580 - ts - Set the default translation domain based on $extensionKey

Reset $extensionKey when loading each file. This puts the onus on developers
to set the extensionKey once in each file using {assign} or {tsScope}, but
it prevents the extension key from leaking unintentionally to other files,
and it allows developers to handle weird situations explicitly.

(Example weird situation -- using one extension to override another
extension's template; or having multiple extensions share a common
translation key.)

----------------------------------------
* CRM-13580: Set translation domain implicitly in extensions
  http://issues.civicrm.org/jira/browse/CRM-13580

CRM/Core/Smarty.php

@@ -159,6 +159,7 @@ class CRM_Core_Smarty extends Smarty {
     }
 
     $this->register_function('crmURL', array('CRM_Utils_System', 'crmURL'));
+    $this->load_filter('pre', 'resetExtScope');
   }
 
   /**

CRM/Core/Smarty/plugins/block.ts.php

@@ -47,6 +47,9 @@
  * @return string  the string, translated by gettext
  */
 function smarty_block_ts($params, $text, &$smarty) {
+  if (!isset($params['domain'])) {
+    $params['domain'] = $smarty->get_template_vars('extensionKey');
+  }
   return ts($text, $params);
 }
 

CRM/Core/Smarty/plugins/prefilter.resetExtScope.php

+<?php
+
+/**
+ * Wrap every Smarty template in a {crmScope} tag that sets the
+ * variable "extensionKey" to blank.
+ */
+function smarty_prefilter_resetExtScope($tpl_source, &$smarty) {
+  return
+    '{crmScope extensionKey=""}'
+    . $tpl_source
+    .'{/crmScope}';
+}
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