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   1  <?php
   2  /**
   3  *
   4  * This file is part of the phpBB Forum Software package.
   5  *
   6  * @copyright (c) phpBB Limited <https://www.phpbb.com>
   7  * @license GNU General Public License, version 2 (GPL-2.0)
   8  *
   9  * For full copyright and license information, please see
  10  * the docs/CREDITS.txt file.
  11  *
  12  */
  13  
  14  namespace phpbb\db;
  15  
  16  /**
  17  * Collects rows for insert into a database until the buffer size is reached.
  18  * Then flushes the buffer to the database and starts over again.
  19  *
  20  * Benefits over collecting a (possibly huge) insert array and then using
  21  * $db->sql_multi_insert() include:
  22  *
  23  *  - Going over max packet size of the database connection is usually prevented
  24  *    because the data is submitted in batches.
  25  *
  26  *  - Reaching database connection timeout is usually prevented because
  27  *    submission of batches talks to the database every now and then.
  28  *
  29  *  - Usage of less PHP memory because data no longer needed is discarded on
  30  *    buffer flush.
  31  *
  32  * Attention:
  33  * Please note that users of this class have to call flush() to flush the
  34  * remaining rows to the database after their batch insert operation is
  35  * finished.
  36  *
  37  * Usage:
  38  * <code>
  39  *    $buffer = new \phpbb\db\sql_insert_buffer($db, 'test_table', 1234);
  40  *
  41  *    while (do_stuff())
  42  *    {
  43  *        $buffer->insert(array(
  44  *            'column1' => 'value1',
  45  *            'column2' => 'value2',
  46  *        ));
  47  *    }
  48  *
  49  *    $buffer->flush();
  50  * </code>
  51  */
  52  class sql_insert_buffer
  53  {
  54      /** @var \phpbb\db\driver\driver_interface */
  55      protected $db;
  56  
  57      /** @var string */
  58      protected $table_name;
  59  
  60      /** @var int */
  61      protected $max_buffered_rows;
  62  
  63      /** @var array */
  64      protected $buffer = array();
  65  
  66      /**
  67      * @param \phpbb\db\driver\driver_interface $db
  68      * @param string          $table_name
  69      * @param int             $max_buffered_rows
  70      */
  71  	public function __construct(\phpbb\db\driver\driver_interface $db, $table_name, $max_buffered_rows = 500)
  72      {
  73          $this->db = $db;
  74          $this->table_name = $table_name;
  75          $this->max_buffered_rows = $max_buffered_rows;
  76      }
  77  
  78      /**
  79      * Inserts a single row into the buffer if multi insert is supported by the
  80      * database (otherwise an insert query is sent immediately). Then flushes
  81      * the buffer if the number of rows in the buffer is now greater than or
  82      * equal to $max_buffered_rows.
  83      *
  84      * @param array $row
  85      *
  86      * @return bool        True when some data was flushed to the database.
  87      *                    False otherwise.
  88      */
  89  	public function insert(array $row)
  90      {
  91          $this->buffer[] = $row;
  92  
  93          // Flush buffer if it is full or when DB does not support multi inserts.
  94          // In the later case, the buffer will always only contain one row.
  95          if (!$this->db->get_multi_insert() || sizeof($this->buffer) >= $this->max_buffered_rows)
  96          {
  97              return $this->flush();
  98          }
  99  
 100          return false;
 101      }
 102  
 103      /**
 104      * Inserts a row set, i.e. an array of rows, by calling insert().
 105      *
 106      * Please note that it is in most cases better to use insert() instead of
 107      * first building a huge rowset. Or at least sizeof($rows) should be kept
 108      * small.
 109      *
 110      * @param array $rows
 111      *
 112      * @return bool        True when some data was flushed to the database.
 113      *                    False otherwise.
 114      */
 115  	public function insert_all(array $rows)
 116      {
 117          // Using bitwise |= because PHP does not have logical ||=
 118          $result = 0;
 119  
 120          foreach ($rows as $row)
 121          {
 122              $result |= (int) $this->insert($row);
 123          }
 124  
 125          return (bool) $result;
 126      }
 127  
 128      /**
 129      * Flushes the buffer content to the DB and clears the buffer.
 130      *
 131      * @return bool        True when some data was flushed to the database.
 132      *                    False otherwise.
 133      */
 134  	public function flush()
 135      {
 136          if (!empty($this->buffer))
 137          {
 138              $this->db->sql_multi_insert($this->table_name, $this->buffer);
 139              $this->buffer = array();
 140  
 141              return true;
 142          }
 143  
 144          return false;
 145      }
 146  }