includes/db/DatabaseUtility.php

   1 <?php
   2 /**
   3  * This file contains database-related utiliy 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                 return $this->currentRow;
 191         }
 192
 193         /**
 194          * @return int
 195          */
 196         function key() {
 197                 return $this->pos;
 198         }
 199
 200         /**
 201          * @return int
 202          */
 203         function next() {
 204                 $this->pos++;
 205                 $this->currentRow = $this->fetchObject();
 206                 return $this->currentRow;
 207         }
 208
 209         /**
 210          * @return bool
 211          */
 212         function valid() {
 213                 return $this->current() !== false;
 214         }
 215 }
 216
 217 /**
 218  * Overloads the relevant methods of the real ResultsWrapper so it
 219  * doesn't go anywhere near an actual database.
 220  */
 221 class FakeResultWrapper extends ResultWrapper {
 222         var $result     = array();
 223         var $db         = null; // And it's going to stay that way :D
 224         var $pos        = 0;
 225         var $currentRow = null;
 226
 227         function __construct( $array ) {
 228                 $this->result = $array;
 229         }
 230
 231         /**
 232          * @return int
 233          */
 234         function numRows() {
 235                 return count( $this->result );
 236         }
 237
 238         function fetchRow() {
 239                 if ( $this->pos < count( $this->result ) ) {
 240                         $this->currentRow = $this->result[$this->pos];
 241                 } else {
 242                         $this->currentRow = false;
 243                 }
 244                 $this->pos++;
 245                 if ( is_object( $this->currentRow ) ) {
 246                         return get_object_vars( $this->currentRow );
 247                 } else {
 248                         return $this->currentRow;
 249                 }
 250         }
 251
 252         function seek( $row ) {
 253                 $this->pos = $row;
 254         }
 255
 256         function free() {}
 257
 258         // Callers want to be able to access fields with $this->fieldName
 259         function fetchObject() {
 260                 $this->fetchRow();
 261                 if ( $this->currentRow ) {
 262                         return (object)$this->currentRow;
 263                 } else {
 264                         return false;
 265                 }
 266         }
 267
 268         function rewind() {
 269                 $this->pos = 0;
 270                 $this->currentRow = null;
 271         }
 272
 273         function next() {
 274                 return $this->fetchObject();
 275         }
 276 }
 277
 278 /**
 279  * Used by DatabaseBase::buildLike() to represent characters that have special meaning in SQL LIKE clauses
 280  * and thus need no escaping. Don't instantiate it manually, use DatabaseBase::anyChar() and anyString() instead.
 281  */
 282 class LikeMatch {
 283         private $str;
 284
 285         /**
 286          * Store a string into a LikeMatch marker object.
 287          *
 288          * @param String $s
 289          */
 290         public function __construct( $s ) {
 291                 $this->str = $s;
 292         }
 293
 294         /**
 295          * Return the original stored string.
 296          *
 297          * @return String
 298          */
 299         public function toString() {
 300                 return $this->str;
 301         }
 302 }
 303
 304 /**
 305  * An object representing a master or slave position in a replicated setup.
 306  */
 307 interface DBMasterPos {
 308 }