diff -r 07239de796bb -r e756a8c72c3d cms/drupal/includes/database/log.inc
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/cms/drupal/includes/database/log.inc	Fri Sep 08 12:04:06 2017 +0200
@@ -0,0 +1,161 @@
+<?php
+
+/**
+ * @file
+ * Logging classes for the database layer.
+ */
+
+/**
+ * Database query logger.
+ *
+ * We log queries in a separate object rather than in the connection object
+ * because we want to be able to see all queries sent to a given database, not
+ * database target. If we logged the queries in each connection object we
+ * would not be able to track what queries went to which target.
+ *
+ * Every connection has one and only one logging object on it for all targets
+ * and logging keys.
+ */
+class DatabaseLog {
+
+  /**
+   * Cache of logged queries. This will only be used if the query logger is enabled.
+   *
+   * The structure for the logging array is as follows:
+   *
+   * array(
+   *   $logging_key = array(
+   *     array(query => '', args => array(), caller => '', target => '', time => 0),
+   *     array(query => '', args => array(), caller => '', target => '', time => 0),
+   *   ),
+   * );
+   *
+   * @var array
+   */
+  protected $queryLog = array();
+
+  /**
+   * The connection key for which this object is logging.
+   *
+   * @var string
+   */
+  protected $connectionKey = 'default';
+
+  /**
+   * Constructor.
+   *
+   * @param $key
+   *   The database connection key for which to enable logging.
+   */
+  public function __construct($key = 'default') {
+    $this->connectionKey = $key;
+  }
+
+  /**
+   * Begin logging queries to the specified connection and logging key.
+   *
+   * If the specified logging key is already running this method does nothing.
+   *
+   * @param $logging_key
+   *   The identification key for this log request. By specifying different
+   *   logging keys we are able to start and stop multiple logging runs
+   *   simultaneously without them colliding.
+   */
+  public function start($logging_key) {
+    if (empty($this->queryLog[$logging_key])) {
+      $this->clear($logging_key);
+    }
+  }
+
+  /**
+   * Retrieve the query log for the specified logging key so far.
+   *
+   * @param $logging_key
+   *   The logging key to fetch.
+   * @return
+   *   An indexed array of all query records for this logging key.
+   */
+  public function get($logging_key) {
+    return $this->queryLog[$logging_key];
+  }
+
+  /**
+   * Empty the query log for the specified logging key.
+   *
+   * This method does not stop logging, it simply clears the log. To stop
+   * logging, use the end() method.
+   *
+   * @param $logging_key
+   *   The logging key to empty.
+   */
+  public function clear($logging_key) {
+    $this->queryLog[$logging_key] = array();
+  }
+
+  /**
+   * Stop logging for the specified logging key.
+   *
+   * @param $logging_key
+   *   The logging key to stop.
+   */
+  public function end($logging_key) {
+    unset($this->queryLog[$logging_key]);
+  }
+
+  /**
+   * Log a query to all active logging keys.
+   *
+   * @param $statement
+   *   The prepared statement object to log.
+   * @param $args
+   *   The arguments passed to the statement object.
+   * @param $time
+   *   The time in milliseconds the query took to execute.
+   */
+  public function log(DatabaseStatementInterface $statement, $args, $time) {
+    foreach (array_keys($this->queryLog) as $key) {
+      $this->queryLog[$key][] = array(
+        'query' => $statement->getQueryString(),
+        'args' => $args,
+        'target' => $statement->dbh->getTarget(),
+        'caller' => $this->findCaller(),
+        'time' => $time,
+      );
+    }
+  }
+
+  /**
+   * Determine the routine that called this query.
+   *
+   * We define "the routine that called this query" as the first entry in
+   * the call stack that is not inside includes/database and does have a file
+   * (which excludes call_user_func_array(), anonymous functions and similar).
+   * That makes the climbing logic very simple, and handles the variable stack
+   * depth caused by the query builders.
+   *
+   * @link http://www.php.net/debug_backtrace
+   * @return
+   *   This method returns a stack trace entry similar to that generated by
+   *   debug_backtrace(). However, it flattens the trace entry and the trace
+   *   entry before it so that we get the function and args of the function that
+   *   called into the database system, not the function and args of the
+   *   database call itself.
+   */
+  public function findCaller() {
+    $stack = debug_backtrace();
+    $stack_count = count($stack);
+    for ($i = 0; $i < $stack_count; ++$i) {
+      if (!empty($stack[$i]['file']) && strpos($stack[$i]['file'], 'includes' . DIRECTORY_SEPARATOR . 'database') === FALSE) {
+        $stack[$i] += array('args' => array());
+        return array(
+          'file' => $stack[$i]['file'],
+          'line' => $stack[$i]['line'],
+          'function' => $stack[$i + 1]['function'],
+          'class' => isset($stack[$i + 1]['class']) ? $stack[$i + 1]['class'] : NULL,
+          'type' => isset($stack[$i + 1]['type']) ? $stack[$i + 1]['type'] : NULL,
+          'args' => $stack[$i + 1]['args'],
+        );
+      }
+    }
+  }
+}