includes/db/DatabaseUtility.php

   1 <?php
   2 /**
   3  * This file contains database-related utility classes.
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  18  * http://www.gnu.org/copyleft/gpl.html
  19  *
  20  * @file
  21  * @ingroup Database
  22  */
  23
  24 /**
  25  * Utility class.
  26  * @ingroup Database
  27  */
  28 class DBObject {
  29         public $mData;
  30
  31         function __construct( $data ) {
  32                 $this->mData = $data;
  33         }
  34
  35         /**
  36          * @return bool
  37          */
  38         function isLOB() {
  39                 return false;
  40         }
  41
  42         function data() {
  43                 return $this->mData;
  44         }
  45 }
  46
  47 /**
  48  * Utility class
  49  * @ingroup Database
  50  *
  51  * This allows us to distinguish a blob from a normal string and an array of strings
  52  */
  53 class Blob {
  54         private $mData;
  55
  56         function __construct( $data ) {
  57                 $this->mData = $data;
  58         }
  59
  60         function fetch() {
  61                 return $this->mData;
  62         }
  63 }
  64
  65 /**
  66  * Base for all database-specific classes representing information about database fields
  67  * @ingroup Database
  68  */
  69 interface Field {
  70         /**
  71          * Field name
  72          * @return string
  73          */
  74         function name();
  75
  76         /**
  77          * Name of table this field belongs to
  78          * @return string
  79          */
  80         function tableName();
  81
  82         /**
  83          * Database type
  84          * @return string
  85          */
  86         function type();
  87
  88         /**
  89          * Whether this field can store NULL values
  90          * @return bool
  91          */
  92         function isNullable();
  93 }
  94
  95 /**
  96  * Result wrapper for grabbing data queried by someone else
  97  * @ingroup Database
  98  */
  99 class ResultWrapper implements Iterator {
 100         var $db, $result, $pos = 0, $currentRow = null;
 101
 102         /**
 103          * Create a new result object from a result resource and a Database object
 104          *
 105          * @param DatabaseBase $database
 106          * @param resource $result
 107          */
 108         function __construct( $database, $result ) {
 109                 $this->db = $database;
 110
 111                 if ( $result instanceof ResultWrapper ) {
 112                         $this->result = $result->result;
 113                 } else {
 114                         $this->result = $result;
 115                 }
 116         }
 117
 118         /**
 119          * Get the number of rows in a result object
 120          *
 121          * @return integer
 122          */
 123         function numRows() {
 124                 return $this->db->numRows( $this );
 125         }
 126
 127         /**
 128          * Fetch the next row from the given result object, in object form.
 129          * Fields can be retrieved with $row->fieldname, with fields acting like
 130          * member variables.
 131          *
 132          * @return object
 133          * @throws DBUnexpectedError Thrown if the database returns an error
 134          */
 135         function fetchObject() {
 136                 return $this->db->fetchObject( $this );
 137         }
 138
 139         /**
 140          * Fetch the next row from the given result object, in associative array
 141          * form. Fields are retrieved with $row['fieldname'].
 142          *
 143          * @return Array
 144          * @throws DBUnexpectedError Thrown if the database returns an error
 145          */
 146         function fetchRow() {
 147                 return $this->db->fetchRow( $this );
 148         }
 149
 150         /**
 151          * Free a result object
 152          */
 153         function free() {
 154                 $this->db->freeResult( $this );
 155                 unset( $this->result );
 156                 unset( $this->db );
 157         }
 158
 159         /**
 160          * Change the position of the cursor in a result object.
 161          * See mysql_data_seek()
 162          *
 163          * @param $row integer
 164          */
 165         function seek( $row ) {
 166                 $this->db->dataSeek( $this, $row );
 167         }
 168
 169         /*********************
 170          * Iterator functions
 171          * Note that using these in combination with the non-iterator functions
 172          * above may cause rows to be skipped or repeated.
 173          */
 174
 175         function rewind() {
 176                 if ( $this->numRows() ) {
 177                         $this->db->dataSeek( $this, 0 );
 178                 }
 179                 $this->pos = 0;
 180                 $this->currentRow = null;
 181         }
 182
 183         /**
 184          * @return int
 185          */
 186         function current() {
 187                 if ( is_null( $this->currentRow ) ) {
 188                         $this->next();
 189                 }
 190
 191                 return $this->currentRow;
 192         }
 193
 194         /**
 195          * @return int
 196          */
 197         function key() {
 198                 return $this->pos;
 199         }
 200
 201         /**
 202          * @return int
 203          */
 204         function next() {
 205                 $this->pos++;
 206                 $this->currentRow = $this->fetchObject();
 207
 208                 return $this->currentRow;
 209         }
 210
 211         /**
 212          * @return bool
 213          */
 214         function valid() {
 215                 return $this->current() !== false;
 216         }
 217 }
 218
 219 /**
 220  * Overloads the relevant methods of the real ResultsWrapper so it
 221  * doesn't go anywhere near an actual database.
 222  */
 223 class FakeResultWrapper extends ResultWrapper {
 224         var $result = array();
 225         var $db = null; // And it's going to stay that way :D
 226         var $pos = 0;
 227         var $currentRow = null;
 228
 229         function __construct( $array ) {
 230                 $this->result = $array;
 231         }
 232
 233         /**
 234          * @return int
 235          */
 236         function numRows() {
 237                 return count( $this->result );
 238         }
 239
 240         function fetchRow() {
 241                 if ( $this->pos < count( $this->result ) ) {
 242                         $this->currentRow = $this->result[$this->pos];
 243                 } else {
 244                         $this->currentRow = false;
 245                 }
 246                 $this->pos++;
 247                 if ( is_object( $this->currentRow ) ) {
 248                         return get_object_vars( $this->currentRow );
 249                 } else {
 250                         return $this->currentRow;
 251                 }
 252         }
 253
 254         function seek( $row ) {
 255                 $this->pos = $row;
 256         }
 257
 258         function free() {
 259         }
 260
 261         // Callers want to be able to access fields with $this->fieldName
 262         function fetchObject() {
 263                 $this->fetchRow();
 264                 if ( $this->currentRow ) {
 265                         return (object)$this->currentRow;
 266                 } else {
 267                         return false;
 268                 }
 269         }
 270
 271         function rewind() {
 272                 $this->pos = 0;
 273                 $this->currentRow = null;
 274         }
 275
 276         function next() {
 277                 return $this->fetchObject();
 278         }
 279 }
 280
 281 /**
 282  * Used by DatabaseBase::buildLike() to represent characters that have special
 283  * meaning in SQL LIKE clauses and thus need no escaping. Don't instantiate it
 284  * manually, use DatabaseBase::anyChar() and anyString() instead.
 285  */
 286 class LikeMatch {
 287         private $str;
 288
 289         /**
 290          * Store a string into a LikeMatch marker object.
 291          *
 292          * @param string $s
 293          */
 294         public function __construct( $s ) {
 295                 $this->str = $s;
 296         }
 297
 298         /**
 299          * Return the original stored string.
 300          *
 301          * @return String
 302          */
 303         public function toString() {
 304                 return $this->str;
 305         }
 306 }
 307
 308 /**
 309  * An object representing a master or slave position in a replicated setup.
 310  */
 311 interface DBMasterPos {
 312 }