includes/DBDataObject.php

   1 <?php
   2
   3 /**
   4  * Abstract base class for representing objects that are stored in some DB table.
   5  * This is basically an ORM-like wrapper around rows in database tables that
   6  * aims to be both simple and very flexible. It is centered around an associative
   7  * array of fields and various methods to do common interaction with the database.
   8  *
   9  * These methods must be implemented in deriving classes:
  10  * * getFieldTypes
  11  *
  12  * These methods are likely candidates for overriding:
  13  * * getDefaults
  14  * * remove
  15  * * insert
  16  * * saveExisting
  17  * * loadSummaryFields
  18  * * getSummaryFields
  19  *
  20  * Deriving classes must register their table and field prefix in $wgDBDataObjects.
  21  * Syntax: $wgDBDataObjects['DrivingClassName'] = array( 'table' => 'table_name', 'prefix' => 'fieldprefix_' );
  22  * Example: $wgDBDataObjects['EPOrg'] = array( 'table' => 'ep_orgs', 'prefix' => 'org_' );
  23  *
  24  * Main instance methods:
  25  * * getField(s)
  26  * * setField(s)
  27  * * save
  28  * * remove
  29  *
  30  * Main static methods:
  31  * * select
  32  * * update
  33  * * delete
  34  * * count
  35  * * has
  36  * * selectRow
  37  * * selectFields
  38  * * selectFieldsRow
  39  *
  40  * @since 1.20
  41  *
  42  * @file DBDataObject.php
  43  *
  44  * @licence GNU GPL v3 or later
  45  * @author Jeroen De Dauw < jeroendedauw@gmail.com >
  46  */
  47 abstract class DBDataObject {
  48
  49         /**
  50          * The fields of the object.
  51          * field name (w/o prefix) => value
  52          *
  53          * @since 1.20
  54          * @var array
  55          */
  56         protected $fields = array( 'id' => null );
  57
  58         /**
  59          * If the object should update summaries of linked items when changed.
  60          * For example, update the course_count field in universities when a course in courses is deleted.
  61          * Settings this to false can prevent needless updating work in situations
  62          * such as deleting a university, which will then delete all it's courses.
  63          *
  64          * @since 1.20
  65          * @var bool
  66          */
  67         protected $updateSummaries = true;
  68
  69         /**
  70          * Indicates if the object is in summary mode.
  71          * This mode indicates that only summary fields got updated,
  72          * which allows for optimizations.
  73          *
  74          * @since 1.20
  75          * @var bool
  76          */
  77         protected $inSummaryMode = false;
  78
  79
  80         /**
  81          * The database connection to use for read operations.
  82          * Can be changed via @see setReadDb.
  83          *
  84          * @since 0.2
  85          * @var integer DB_ enum
  86          */
  87         protected static $readDb = DB_SLAVE;
  88
  89         /**
  90          * Returns the name of the database table objects of this type are stored in.
  91          *
  92          * @since 1.20
  93          *
  94          * @throws MWException
  95          * @return string
  96          */
  97         public static function getDBTable() {
  98                 global $wgDBDataObjects;
  99                 if ( array_key_exists( get_called_class(), $wgDBDataObjects ) ) {
 100                         return $wgDBDataObjects[get_called_class()]['table'];
 101                 }
 102                 else {
 103                         throw new MWException( 'Class "' . get_called_class() . '" not found in $wgDBDataObjects' );
 104                 }
 105         }
 106
 107         /**
 108          * Gets the db field prefix.
 109          *
 110          * @since 1.20
 111          *
 112          * @throws MWException
 113          * @return string
 114          */
 115         protected static function getFieldPrefix() {
 116                 global $wgDBDataObjects;
 117                 if ( array_key_exists( get_called_class(), $wgDBDataObjects ) ) {
 118                         return $wgDBDataObjects[get_called_class()]['prefix'];
 119                 }
 120                 else {
 121                         throw new MWException( 'Class "' . get_called_class() . '" not found in $wgDBDataObjects' );
 122                 }
 123         }
 124
 125         /**
 126          * Returns an array with the fields and their types this object contains.
 127          * This corresponds directly to the fields in the database, without prefix.
 128          *
 129          * field name => type
 130          *
 131          * Allowed types:
 132          * * id
 133          * * str
 134          * * int
 135          * * float
 136          * * bool
 137          * * array
 138          *
 139          * @since 1.20
 140          *
 141          * @throws MWException
 142          * @return array
 143          */
 144         protected static function getFieldTypes() {
 145                 throw new MWException( 'Class did not implement getFieldTypes' );
 146         }
 147
 148         /**
 149          * Returns a list of default field values.
 150          * field name => field value
 151          *
 152          * @since 1.20
 153          *
 154          * @return array
 155          */
 156         public static function getDefaults() {
 157                 return array();
 158         }
 159
 160         /**
 161          * Returns a list of the summary fields.
 162          * These are fields that cache computed values, such as the amount of linked objects of $type.
 163          * This is relevant as one might not want to do actions such as log changes when these get updated.
 164          *
 165          * @since 1.20
 166          *
 167          * @return array
 168          */
 169         public static function getSummaryFields() {
 170                 return array();
 171         }
 172
 173         /**
 174          * Constructor.
 175          *
 176          * @since 1.20
 177          *
 178          * @param array|null $fields
 179          * @param boolean $loadDefaults
 180          */
 181         public function __construct( $fields = null, $loadDefaults = false ) {
 182                 if ( !is_array( $fields ) ) {
 183                         $fields = array();
 184                 }
 185
 186                 if ( $loadDefaults ) {
 187                         $fields = array_merge( $this->getDefaults(), $fields );
 188                 }
 189
 190                 $this->setFields( $fields );
 191         }
 192
 193         /**
 194          * Load the specified fields from the database.
 195          *
 196          * @since 1.20
 197          *
 198          * @param array|null $fields
 199          * @param boolean $override
 200          * @param boolean $skipLoaded
 201          *
 202          * @return Success indicator
 203          */
 204         public function loadFields( $fields = null, $override = true, $skipLoaded = false ) {
 205                 if ( is_null( $this->getId() ) ) {
 206                         return false;
 207                 }
 208
 209                 if ( is_null( $fields ) ) {
 210                         $fields = array_keys( $this->getFieldTypes() );
 211                 }
 212
 213                 if ( $skipLoaded ) {
 214                         $loadedFields = array_keys( $this->fields );
 215                         $fields = array_filter( $fields, function( $field ) use ( $loadedFields ) {
 216                                 return !in_array( $field, $loadedFields );
 217                         } );
 218                 }
 219
 220                 if ( count( $fields ) > 0 ) {
 221                         $results = $this->rawSelect(
 222                                 $this->getPrefixedFields( $fields ),
 223                                 array( $this->getPrefixedField( 'id' ) => $this->getId() ),
 224                                 array( 'LIMIT' => 1 )
 225                         );
 226
 227                         foreach ( $results as $result ) {
 228                                 $this->setFields( $this->getFieldsFromDBResult( $result ), $override );
 229                                 return true;
 230                         }
 231
 232                         return false;
 233                 }
 234
 235                 return true;
 236         }
 237
 238         /**
 239          * Gets the value of a field.
 240          *
 241          * @since 1.20
 242          *
 243          * @param string $name
 244          * @param mixed $default
 245          *
 246          * @throws MWException
 247          * @return mixed
 248          */
 249         public function getField( $name, $default = null ) {
 250                 if ( $this->hasField( $name ) ) {
 251                         return $this->fields[$name];
 252                 } elseif ( !is_null( $default ) ) {
 253                         return $default;
 254                 } else {
 255                         throw new MWException( 'Attempted to get not-set field ' . $name );
 256                 }
 257         }
 258
 259         /**
 260          * Gets the value of a field but first loads it if not done so already.
 261          *
 262          * @since 1.20
 263          *
 264          * @param string$name
 265          *
 266          * @return mixed
 267          */
 268         public function loadAndGetField( $name ) {
 269                 if ( !$this->hasField( $name ) ) {
 270                         $this->loadFields( array( $name ) );
 271                 }
 272
 273                 return $this->getField( $name );
 274         }
 275
 276         /**
 277          * Remove a field.
 278          *
 279          * @since 1.20
 280          *
 281          * @param string $name
 282          */
 283         public function removeField( $name ) {
 284                 unset( $this->fields[$name] );
 285         }
 286
 287         /**
 288          * Returns the objects database id.
 289          *
 290          * @since 1.20
 291          *
 292          * @return integer|null
 293          */
 294         public function getId() {
 295                 return $this->getField( 'id' );
 296         }
 297
 298         /**
 299          * Sets the objects database id.
 300          *
 301          * @since 1.20
 302          *
 303          * @param integer|null $id
 304          */
 305         public function setId( $id ) {
 306                 return $this->setField( 'id', $id );
 307         }
 308
 309         /**
 310          * Gets if a certain field is set.
 311          *
 312          * @since 1.20
 313          *
 314          * @param string $name
 315          *
 316          * @return boolean
 317          */
 318         public function hasField( $name ) {
 319                 return array_key_exists( $name, $this->fields );
 320         }
 321
 322         /**
 323          * Gets if the id field is set.
 324          *
 325          * @since 1.20
 326          *
 327          * @return boolean
 328          */
 329         public function hasIdField() {
 330                 return $this->hasField( 'id' )
 331                         && !is_null( $this->getField( 'id' ) );
 332         }
 333
 334         /**
 335          * Sets multiple fields.
 336          *
 337          * @since 1.20
 338          *
 339          * @param array $fields The fields to set
 340          * @param boolean $override Override already set fields with the provided values?
 341          */
 342         public function setFields( array $fields, $override = true ) {
 343                 foreach ( $fields as $name => $value ) {
 344                         if ( $override || !$this->hasField( $name ) ) {
 345                                 $this->setField( $name, $value );
 346                         }
 347                 }
 348         }
 349
 350         /**
 351          * Gets the fields => values to write to the table.
 352          *
 353          * @since 1.20
 354          *
 355          * @return array
 356          */
 357         protected function getWriteValues() {
 358                 $values = array();
 359
 360                 foreach ( $this->getFieldTypes() as $name => $type ) {
 361                         if ( array_key_exists( $name, $this->fields ) ) {
 362                                 $value = $this->fields[$name];
 363
 364                                 switch ( $type ) {
 365                                         case 'array':
 366                                                 $value = (array)$value;
 367                                         case 'blob':
 368                                                 $value = serialize( $value );
 369                                 }
 370
 371                                 $values[$this->getFieldPrefix() . $name] = $value;
 372                         }
 373                 }
 374
 375                 return $values;
 376         }
 377
 378         /**
 379          * Serializes the object to an associative array which
 380          * can then easily be converted into JSON or similar.
 381          *
 382          * @since 1.20
 383          *
 384          * @param null|array $fields
 385          * @param boolean $incNullId
 386          *
 387          * @return array
 388          */
 389         public function toArray( $fields = null, $incNullId = false ) {
 390                 $data = array();
 391                 $setFields = array();
 392
 393                 if ( !is_array( $fields ) ) {
 394                         $setFields = $this->getSetFieldNames();
 395                 } else {
 396                         foreach ( $fields as $field ) {
 397                                 if ( $this->hasField( $field ) ) {
 398                                         $setFields[] = $field;
 399                                 }
 400                         }
 401                 }
 402
 403                 foreach ( $setFields as $field ) {
 404                         if ( $incNullId || $field != 'id' || $this->hasIdField() ) {
 405                                 $data[$field] = $this->getField( $field );
 406                         }
 407                 }
 408
 409                 return $data;
 410         }
 411
 412         /**
 413          * Load the default values, via getDefaults.
 414          *
 415          *  @since 1.20
 416          *
 417          * @param boolean $override
 418          */
 419         public function loadDefaults( $override = true ) {
 420                 $this->setFields( $this->getDefaults(), $override );
 421         }
 422
 423         /**
 424          * Writes the answer to the database, either updating it
 425          * when it already exists, or inserting it when it doesn't.
 426          *
 427          * @since 1.20
 428          *
 429          * @return boolean Success indicator
 430          */
 431         public function save() {
 432                 if ( $this->hasIdField() ) {
 433                         return $this->saveExisting();
 434                 } else {
 435                         return $this->insert();
 436                 }
 437         }
 438
 439         /**
 440          * Updates the object in the database.
 441          *
 442          * @since 1.20
 443          *
 444          * @return boolean Success indicator
 445          */
 446         protected function saveExisting() {
 447                 $dbw = wfGetDB( DB_MASTER );
 448
 449                 $success = $dbw->update(
 450                         $this->getDBTable(),
 451                         $this->getWriteValues(),
 452                         array( $this->getFieldPrefix() . 'id' => $this->getId() ),
 453                         __METHOD__
 454                 );
 455
 456                 return $success;
 457         }
 458
 459         /**
 460          * Inserts the object into the database.
 461          *
 462          * @since 1.20
 463          *
 464          * @return boolean Success indicator
 465          */
 466         protected function insert() {
 467                 $dbw = wfGetDB( DB_MASTER );
 468
 469                 $result = $dbw->insert(
 470                         $this->getDBTable(),
 471                         $this->getWriteValues(),
 472                         __METHOD__,
 473                         array( 'IGNORE' )
 474                 );
 475
 476                 if ( $result ) {
 477                         $this->setField( 'id', $dbw->insertId() );
 478                 }
 479
 480                 return $result;
 481         }
 482
 483         /**
 484          * Removes the object from the database.
 485          *
 486          * @since 1.20
 487          *
 488          * @return boolean Success indicator
 489          */
 490         public function remove() {
 491                 $this->beforeRemove();
 492
 493                 $success = static::delete( array( 'id' => $this->getId() ) );
 494
 495                 if ( $success ) {
 496                         $this->onRemoved();
 497                 }
 498
 499                 return $success;
 500         }
 501
 502         /**
 503          * Gets called before an object is removed from the database.
 504          *
 505          * @since 1.20
 506          */
 507         protected function beforeRemove() {
 508                 $this->loadFields( $this->getBeforeRemoveFields(), false, true );
 509         }
 510
 511         /**
 512          * Before removal of an object happens, @see beforeRemove gets called.
 513          * This method loads the fields of which the names have been returned by this one (or all fields if null is returned).
 514          * This allows for loading info needed after removal to get rid of linked data and the like.
 515          *
 516          * @since 1.20
 517          *
 518          * @return array|null
 519          */
 520         protected function getBeforeRemoveFields() {
 521                 return array();
 522         }
 523
 524         /**
 525          * Gets called after successfull removal.
 526          * Can be overriden to get rid of linked data.
 527          *
 528          * @since 1.20
 529          */
 530         protected function onRemoved() {
 531                 $this->setField( 'id', null );
 532         }
 533
 534         /**
 535          * Return the names and values of the fields.
 536          *
 537          * @since 1.20
 538          *
 539          * @return array
 540          */
 541         public function getFields() {
 542                 return $this->fields;
 543         }
 544
 545         /**
 546          * Return the names of the fields.
 547          *
 548          * @since 1.20
 549          *
 550          * @return array
 551          */
 552         public function getSetFieldNames() {
 553                 return array_keys( $this->fields );
 554         }
 555
 556         /**
 557          * Sets the value of a field.
 558          * Strings can be provided for other types,
 559          * so this method can be called from unserialization handlers.
 560          *
 561          * @since 1.20
 562          *
 563          * @param string $name
 564          * @param mixed $value
 565          *
 566          * @throws MWException
 567          */
 568         public function setField( $name, $value ) {
 569                 $fields = $this->getFieldTypes();
 570
 571                 if ( array_key_exists( $name, $fields ) ) {
 572                         switch ( $fields[$name] ) {
 573                                 case 'int':
 574                                         $value = (int)$value;
 575                                         break;
 576                                 case 'float':
 577                                         $value = (float)$value;
 578                                         break;
 579                                 case 'bool':
 580                                         if ( is_string( $value ) ) {
 581                                                 $value = $value !== '0';
 582                                         } elseif ( is_int( $value ) ) {
 583                                                 $value = $value !== 0;
 584                                         }
 585                                         break;
 586                                 case 'array':
 587                                         if ( is_string( $value ) ) {
 588                                                 $value = unserialize( $value );
 589                                         }
 590
 591                                         if ( !is_array( $value ) ) {
 592                                                 $value = array();
 593                                         }
 594                                         break;
 595                                 case 'blob':
 596                                         if ( is_string( $value ) ) {
 597                                                 $value = unserialize( $value );
 598                                         }
 599                                         break;
 600                                 case 'id':
 601                                         if ( is_string( $value ) ) {
 602                                                 $value = (int)$value;
 603                                         }
 604                                         break;
 605                         }
 606
 607                         $this->fields[$name] = $value;
 608                 } else {
 609                         throw new MWException( 'Attempted to set unknown field ' . $name );
 610                 }
 611         }
 612
 613         /**
 614          * Get a new instance of the class from an array.
 615          *
 616          * @since 1.20
 617          *
 618          * @param array $data
 619          * @param boolean $loadDefaults
 620          *
 621          * @return DBDataObject
 622          */
 623         public static function newFromArray( array $data, $loadDefaults = false ) {
 624                 return new static( $data, $loadDefaults );
 625         }
 626
 627         /**
 628          * Get the database type used for read operations.
 629          *
 630          * @since 0.2
 631          * @return integer DB_ enum
 632          */
 633         public static function getReadDb() {
 634                 return self::$readDb;
 635         }
 636
 637         /**
 638          * Set the database type to use for read operations.
 639          *
 640          * @param integer $db
 641          *
 642          * @since 0.2
 643          */
 644         public static function setReadDb( $db ) {
 645                 self::$readDb = $db;
 646         }
 647
 648         /**
 649          * Gets if the object can take a certain field.
 650          *
 651          * @since 1.20
 652          *
 653          * @param string $name
 654          *
 655          * @return boolean
 656          */
 657         public static function canHasField( $name ) {
 658                 return array_key_exists( $name, static::getFieldTypes() );
 659         }
 660
 661         /**
 662          * Takes in a field or array of fields and returns an
 663          * array with their prefixed versions, ready for db usage.
 664          *
 665          * @since 1.20
 666          *
 667          * @param array|string $fields
 668          *
 669          * @return array
 670          */
 671         public static function getPrefixedFields( array $fields ) {
 672                 foreach ( $fields as &$field ) {
 673                         $field = static::getPrefixedField( $field );
 674                 }
 675
 676                 return $fields;
 677         }
 678
 679         /**
 680          * Takes in a field and returns an it's prefixed version, ready for db usage.
 681          * If the field needs to be prefixed for another table, provide an array in the form
 682          * array( 'tablename', 'fieldname' )
 683          * Where table name is registered in $wgDBDataObjects.
 684          *
 685          * @since 1.20
 686          *
 687          * @param string|array $field
 688          *
 689          * @return string
 690          * @throws MWException
 691          */
 692         public static function getPrefixedField( $field ) {
 693                 static $prefixes = false;
 694
 695                 if ( $prefixes === false ) {
 696                         foreach ( $GLOBALS['wgDBDataObjects'] as $classInfo ) {
 697                                 $prefixes[$classInfo['table']] = $classInfo['prefix'];
 698                         }
 699                 }
 700
 701                 if ( is_array( $field ) && count( $field ) > 1 ) {
 702                         if ( array_key_exists( $field[0], $prefixes ) ) {
 703                                 $prefix = $prefixes[$field[0]];
 704                                 $field = $field[1];
 705                         }
 706                         else {
 707                                 throw new MWException( 'Tried to prefix field with unknown table "' . $field[0] . '"' );
 708                         }
 709                 }
 710                 else {
 711                         $prefix = static::getFieldPrefix();
 712                 }
 713
 714                 return $prefix . $field;
 715         }
 716
 717         /**
 718          * Takes in an associative array with field names as keys and
 719          * their values as value. The field names are prefixed with the
 720          * db field prefix.
 721          *
 722          * Field names can also be provided as an array with as first element a table name, such as
 723          * $conditions = array(
 724          *       array( array( 'tablename', 'fieldname' ), $value ),
 725          * );
 726          *
 727          * @since 1.20
 728          *
 729          * @param array $values
 730          *
 731          * @return array
 732          */
 733         public static function getPrefixedValues( array $values ) {
 734                 $prefixedValues = array();
 735
 736                 foreach ( $values as $field => $value ) {
 737                         if ( is_integer( $field ) ) {
 738                                 if ( is_array( $value ) ) {
 739                                         $field = $value[0];
 740                                         $value = $value[1];
 741                                 }
 742                                 else {
 743                                         $value = explode( ' ', $value, 2 );
 744                                         $value[0] = static::getPrefixedField( $value[0] );
 745                                         $prefixedValues[] = implode( ' ', $value );
 746                                         continue;
 747                                 }
 748                         }
 749
 750                         $prefixedValues[static::getPrefixedField( $field )] = $value;
 751                 }
 752
 753                 return $prefixedValues;
 754         }
 755
 756         /**
 757          * Get an array with fields from a database result,
 758          * that can be fed directly to the constructor or
 759          * to setFields.
 760          *
 761          * @since 1.20
 762          *
 763          * @param object $result
 764          *
 765          * @return array
 766          */
 767         public static function getFieldsFromDBResult( $result ) {
 768                 $result = (array)$result;
 769                 return array_combine(
 770                         static::unprefixFieldNames( array_keys( $result ) ),
 771                         array_values( $result )
 772                 );
 773         }
 774
 775         /**
 776          * Takes a field name with prefix and returns the unprefixed equivalent.
 777          *
 778          * @since 1.20
 779          *
 780          * @param string $fieldName
 781          *
 782          * @return string
 783          */
 784         public static function unprefixFieldName( $fieldName ) {
 785                 return substr( $fieldName, strlen( static::getFieldPrefix() ) );
 786         }
 787
 788         /**
 789          * Takes an array of field names with prefix and returns the unprefixed equivalent.
 790          *
 791          * @since 1.20
 792          *
 793          * @param array $fieldNames
 794          *
 795          * @return array
 796          */
 797         public static function unprefixFieldNames( array $fieldNames ) {
 798                 return array_map( 'static::unprefixFieldName', $fieldNames );
 799         }
 800
 801         /**
 802          * Get a new instance of the class from a database result.
 803          *
 804          * @since 1.20
 805          *
 806          * @param stdClass $result
 807          *
 808          * @return DBDataObject
 809          */
 810         public static function newFromDBResult( stdClass $result ) {
 811                 return static::newFromArray( static::getFieldsFromDBResult( $result ) );
 812         }
 813
 814         /**
 815          * Removes the object from the database.
 816          *
 817          * @since 1.20
 818          *
 819          * @param array $conditions
 820          *
 821          * @return boolean Success indicator
 822          */
 823         public static function delete( array $conditions ) {
 824                 return wfGetDB( DB_MASTER )->delete(
 825                         static::getDBTable(),
 826                         static::getPrefixedValues( $conditions )
 827                 );
 828         }
 829
 830         /**
 831          * Add an amount (can be negative) to the specified field (needs to be numeric).
 832          *
 833          * @since 1.20
 834          *
 835          * @param string $field
 836          * @param integer $amount
 837          *
 838          * @return boolean Success indicator
 839          */
 840         public static function addToField( $field, $amount ) {
 841                 if ( $amount == 0 ) {
 842                         return true;
 843                 }
 844
 845                 if ( !static::hasIdField() ) {
 846                         return false;
 847                 }
 848
 849                 $absoluteAmount = abs( $amount );
 850                 $isNegative = $amount < 0;
 851
 852                 $dbw = wfGetDB( DB_MASTER );
 853
 854                 $fullField = static::getPrefixedField( $field );
 855
 856                 $success = $dbw->update(
 857                         static::getDBTable(),
 858                         array( "$fullField=$fullField" . ( $isNegative ? '-' : '+' ) . $absoluteAmount ),
 859                         array( static::getPrefixedField( 'id' ) => static::getId() ),
 860                         __METHOD__
 861                 );
 862
 863                 if ( $success && static::hasField( $field ) ) {
 864                         static::setField( $field, static::getField( $field ) + $amount );
 865                 }
 866
 867                 return $success;
 868         }
 869
 870         /**
 871          * Selects the the specified fields of the records matching the provided
 872          * conditions and returns them as DBDataObject. Field names get prefixed.
 873          *
 874          * @since 1.20
 875          *
 876          * @param array|string|null $fields
 877          * @param array $conditions
 878          * @param array $options
 879          * @param array $joinConds
 880          *
 881          * @return array of self
 882          */
 883         public static function select( $fields = null, array $conditions = array(), array $options = array(), array $joinConds = array() ) {
 884                 $result = static::selectFields( $fields, $conditions, $options, $joinConds, false );
 885
 886                 $objects = array();
 887
 888                 foreach ( $result as $record ) {
 889                         $objects[] = static::newFromArray( $record );
 890                 }
 891
 892                 return $objects;
 893         }
 894
 895         /**
 896          * Selects the the specified fields of the records matching the provided
 897          * conditions and returns them as associative arrays.
 898          * Provided field names get prefixed.
 899          * Returned field names will not have a prefix.
 900          *
 901          * When $collapse is true:
 902          * If one field is selected, each item in the result array will be this field.
 903          * If two fields are selected, each item in the result array will have as key
 904          * the first field and as value the second field.
 905          * If more then two fields are selected, each item will be an associative array.
 906          *
 907          * @since 1.20
 908          *
 909          * @param array|string|null $fields
 910          * @param array $conditions
 911          * @param array $options
 912          * @param array $joinConds
 913          * @param boolean $collapse Set to false to always return each result row as associative array.
 914          *
 915          * @return array of array
 916          */
 917         public static function selectFields( $fields = null, array $conditions = array(), array $options = array(), array $joinConds = array(), $collapse = true ) {
 918                 if ( is_null( $fields ) ) {
 919                         $fields = array_keys( static::getFieldTypes() );
 920                 }
 921                 else {
 922                         $fields = (array)$fields;
 923                 }
 924
 925                 $tables = array( static::getDBTable() );
 926                 $joinConds = static::getProcessedJoinConds( $joinConds, $tables );
 927
 928                 $result = static::rawSelect(
 929                         static::getPrefixedFields( $fields ),
 930                         static::getPrefixedValues( $conditions ),
 931                         $options,
 932                         $joinConds,
 933                         $tables
 934                 );
 935
 936                 $objects = array();
 937
 938                 foreach ( $result as $record ) {
 939                         $objects[] = static::getFieldsFromDBResult( $record );
 940                 }
 941
 942                 if ( $collapse ) {
 943                         if ( count( $fields ) === 1 ) {
 944                                 $objects = array_map( function( $object ) { return array_shift( $object ); } , $objects );
 945                         }
 946                         elseif ( count( $fields ) === 2 ) {
 947                                 $o = array();
 948
 949                                 foreach ( $objects as $object ) {
 950                                         $o[array_shift( $object )] = array_shift( $object );
 951                                 }
 952
 953                                 $objects = $o;
 954                         }
 955                 }
 956
 957                 return $objects;
 958         }
 959
 960         /**
 961          * Process the join conditions. This includes prefixing table and field names,
 962          * and adding of needed tables.
 963          *
 964          * @since 1.20
 965          *
 966          * @param array $joinConds Join conditions without prefixes and fields in array rather then string with equals sign.
 967          * @param array $tables List of tables to which the extra needed ones get added.
 968          *
 969          * @return array Join conditions ready to be fed to MediaWikis native select function.
 970          */
 971         protected static function getProcessedJoinConds( array $joinConds, array &$tables ) {
 972                 $conds = array();
 973
 974                 foreach ( $joinConds as $table => $joinCond ) {
 975                         if ( !in_array( $table, $tables ) ) {
 976                                 $tables[] = $table;
 977                         }
 978
 979                         $cond = array( $joinCond[0], array() );
 980
 981                         foreach ( $joinCond[1] as $joinCondPart ) {
 982                                 $parts = array(
 983                                         static::getPrefixedField( $joinCondPart[0] ),
 984                                         static::getPrefixedField( $joinCondPart[1] ),
 985                                 );
 986
 987                                 if ( !in_array( $joinCondPart[0][0], $tables ) ) {
 988                                         $tables[] = $joinCondPart[0][0];
 989                                 }
 990
 991                                 if ( !in_array( $joinCondPart[1][0], $tables ) ) {
 992                                         $tables[] = $joinCondPart[1][0];
 993                                 }
 994
 995                                 $cond[1][] = implode( '=', $parts );
 996                         }
 997
 998                         $conds[$table] = $cond;
 999                 }
1000
1001                 return $conds;
1002         }
1003
1004         /**
1005          * Selects the the specified fields of the first matching record.
1006          * Field names get prefixed.
1007          *
1008          * @since 1.20
1009          *
1010          * @param array|string|null $fields
1011          * @param array $conditions
1012          * @param array $options
1013          * @param array $joinConds
1014          *
1015          * @return EPBObject|false
1016          */
1017         public static function selectRow( $fields = null, array $conditions = array(), array $options = array(), array $joinConds = array() ) {
1018                 $options['LIMIT'] = 1;
1019
1020                 $objects = static::select( $fields, $conditions, $options, $joinConds );
1021
1022                 return count( $objects ) > 0 ? $objects[0] : false;
1023         }
1024
1025         /**
1026          * Selects the the specified fields of the first record matching the provided
1027          * conditions and returns it as an associative array, or false when nothing matches.
1028          * This method makes use of selectFields and expects the same parameters and
1029          * returns the same results (if there are any, if there are none, this method returns false).
1030          * @see DBDataObject::selectFields
1031          *
1032          * @since 1.20
1033          *
1034          * @param array|string|null $fields
1035          * @param array $conditions
1036          * @param array $options
1037          * @param array $joinConds
1038          * @param boolean $collapse Set to false to always return each result row as associative array.
1039          *
1040          * @return mixed|array|false
1041          */
1042         public static function selectFieldsRow( $fields = null, array $conditions = array(), array $options = array(), array $joinConds = array(), $collapse = true ) {
1043                 $options['LIMIT'] = 1;
1044
1045                 $objects = static::selectFields( $fields, $conditions, $options, $joinConds, $collapse );
1046
1047                 return count( $objects ) > 0 ? $objects[0] : false;
1048         }
1049
1050         /**
1051          * Returns if there is at least one record matching the provided conditions.
1052          * Condition field names get prefixed.
1053          *
1054          * @since 1.20
1055          *
1056          * @param array $conditions
1057          *
1058          * @return boolean
1059          */
1060         public static function has( array $conditions = array() ) {
1061                 return static::selectRow( array( 'id' ), $conditions ) !== false;
1062         }
1063
1064         /**
1065          * Returns the amount of matching records.
1066          * Condition field names get prefixed.
1067          *
1068          * @since 1.20
1069          *
1070          * @param array $conditions
1071          * @param array $options
1072          *
1073          * @return integer
1074          */
1075         public static function count( array $conditions = array(), array $options = array() ) {
1076                 $res = static::rawSelect(
1077                         array( 'COUNT(*) AS rowcount' ),
1078                         static::getPrefixedValues( $conditions ),
1079                         $options
1080                 )->fetchObject();
1081
1082                 return $res->rowcount;
1083         }
1084
1085         /**
1086          * Selects the the specified fields of the records matching the provided
1087          * conditions. Field names do NOT get prefixed.
1088          *
1089          * @since 1.20
1090          *
1091          * @param array $fields
1092          * @param array $conditions
1093          * @param array $options
1094          * @param array $joinConds
1095          * @param array $tables
1096          *
1097          * @return ResultWrapper
1098          */
1099         public static function rawSelect( array $fields, array $conditions = array(), array $options = array(), array $joinConds = array(), array $tables = null ) {
1100                 if ( is_null( $tables ) ) {
1101                         $tables = static::getDBTable();
1102                 }
1103
1104                 $dbr = wfGetDB( static::getReadDb() );
1105
1106                 return $dbr->select(
1107                         $tables,
1108                         $fields,
1109                         count( $conditions ) == 0 ? '' : $conditions,
1110                         __METHOD__,
1111                         $options,
1112                         $joinConds
1113                 );
1114         }
1115
1116         /**
1117          * Update the records matching the provided conditions by
1118          * setting the fields that are keys in the $values param to
1119          * their corresponding values.
1120          *
1121          * @since 1.20
1122          *
1123          * @param array $values
1124          * @param array $conditions
1125          *
1126          * @return boolean Success indicator
1127          */
1128         public static function update( array $values, array $conditions = array() ) {
1129                 $dbw = wfGetDB( DB_MASTER );
1130
1131                 return $dbw->update(
1132                         static::getDBTable(),
1133                         static::getPrefixedValues( $values ),
1134                         static::getPrefixedValues( $conditions ),
1135                         __METHOD__
1136                 );
1137         }
1138
1139         /**
1140          * Return the names of the fields.
1141          *
1142          * @since 1.20
1143          *
1144          * @return array
1145          */
1146         public static function getFieldNames() {
1147                 return array_keys( static::getFieldTypes() );
1148         }
1149
1150         /**
1151          * Returns an array with the fields and their descriptions.
1152          *
1153          * field name => field description
1154          *
1155          * @since 1.20
1156          *
1157          * @return array
1158          */
1159         public static function getFieldDescriptions() {
1160                 return array();
1161         }
1162
1163         /**
1164          * Get API parameters for the fields supported by this object.
1165          *
1166          * @since 1.20
1167          *
1168          * @param boolean $requireParams
1169          * @param boolean $setDefaults
1170          *
1171          * @return array
1172          */
1173         public static function getAPIParams( $requireParams = false, $setDefaults = false ) {
1174                 $typeMap = array(
1175                         'id' => 'integer',
1176                         'int' => 'integer',
1177                         'float' => 'NULL',
1178                         'str' => 'string',
1179                         'bool' => 'integer',
1180                         'array' => 'string',
1181                         'blob' => 'string',
1182                 );
1183
1184                 $params = array();
1185                 $defaults = static::getDefaults();
1186
1187                 foreach ( static::getFieldTypes() as $field => $type ) {
1188                         if ( $field == 'id' ) {
1189                                 continue;
1190                         }
1191
1192                         $hasDefault = array_key_exists( $field, $defaults );
1193
1194                         $params[$field] = array(
1195                                 ApiBase::PARAM_TYPE => $typeMap[$type],
1196                                 ApiBase::PARAM_REQUIRED => $requireParams && !$hasDefault
1197                         );
1198
1199                         if ( $type == 'array' ) {
1200                                 $params[$field][ApiBase::PARAM_ISMULTI] = true;
1201                         }
1202
1203                         if ( $setDefaults && $hasDefault ) {
1204                                 $default = is_array( $defaults[$field] ) ? implode( '|', $defaults[$field] ) : $defaults[$field];
1205                                 $params[$field][ApiBase::PARAM_DFLT] = $default;
1206                         }
1207                 }
1208
1209                 return $params;
1210         }
1211
1212         /**
1213          * Computes and updates the values of the summary fields.
1214          *
1215          * @since 1.20
1216          *
1217          * @param array|string|null $summaryFields
1218          */
1219         public function loadSummaryFields( $summaryFields = null ) {
1220
1221         }
1222
1223         /**
1224          * Computes the values of the summary fields of the objects matching the provided conditions.
1225          *
1226          * @since 1.20
1227          *
1228          * @param array|string|null $summaryFields
1229          * @param array $conditions
1230          */
1231         public static function updateSummaryFields( $summaryFields = null, array $conditions = array() ) {
1232                 self::setReadDb( DB_MASTER );
1233
1234                 foreach ( self::select( null, $conditions ) as /* DBDataObject */ $item ) {
1235                         $item->loadSummaryFields( $summaryFields );
1236                         $item->setSummaryMode( true );
1237                         $item->saveExisting();
1238                 }
1239
1240                 self::setReadDb( DB_SLAVE );
1241         }
1242
1243         /**
1244          * Sets the value for the @see $updateSummaries field.
1245          *
1246          * @since 1.20
1247          *
1248          * @param boolean $update
1249          */
1250         public function setUpdateSummaries( $update ) {
1251                 $this->updateSummaries = $update;
1252         }
1253
1254         /**
1255          * Sets the value for the @see $inSummaryMode field.
1256          *
1257          * @since 1.20
1258          *
1259          * @param boolean $update
1260          */
1261         public function setSummaryMode( $summaryMode ) {
1262                 $this->inSummaryMode = $summaryMode;
1263         }
1264
1265         /**
1266          * Return if any fields got changed.
1267          *
1268          * @since 1.20
1269          *
1270          * @param DBDataObject $object
1271          * @param boolean $excludeSummaryFields When set to true, summary field changes are ignored.
1272          *
1273          * @return boolean
1274          */
1275         protected function fieldsChanged( DBDataObject $object, $excludeSummaryFields = false ) {
1276                 foreach ( $this->fields as $name => $value ) {
1277                         $excluded = $excludeSummaryFields && in_array( $name, $this->getSummaryFields() );
1278
1279                         if ( !$excluded && $object->getField( $name ) !== $value ) {
1280                                 return true;
1281                         }
1282                 }
1283
1284                 return false;
1285         }
1286
1287 }