MediaWiki  1.28.0
BatchRowIterator.php
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1 <?php
26 class BatchRowIterator implements RecursiveIterator {
27 
31  protected $db;
32 
36  protected $table;
37 
41  protected $primaryKey;
42 
46  protected $batchSize;
47 
52  protected $conditions = [];
53 
57  protected $joinConditions = [];
58 
63  protected $fetchColumns;
64 
68  protected $orderBy;
69 
73  private $current = [];
74 
78  private $key;
79 
83  protected $options = [];
84 
93  if ( $batchSize < 1 ) {
94  throw new InvalidArgumentException( 'Batch size must be at least 1 row.' );
95  }
96  $this->db = $db;
97  $this->table = $table;
98  $this->primaryKey = (array)$primaryKey;
99  $this->fetchColumns = $this->primaryKey;
100  $this->orderBy = implode( ' ASC,', $this->primaryKey ) . ' ASC';
101  $this->batchSize = $batchSize;
102  }
103 
108  public function addConditions( array $conditions ) {
109  $this->conditions = array_merge( $this->conditions, $conditions );
110  }
111 
116  public function addOptions( array $options ) {
117  $this->options = array_merge( $this->options, $options );
118  }
119 
124  public function addJoinConditions( array $conditions ) {
125  $this->joinConditions = array_merge( $this->joinConditions, $conditions );
126  }
127 
132  public function setFetchColumns( array $columns ) {
133  // If it's not the all column selector merge in the primary keys we need
134  if ( count( $columns ) === 1 && reset( $columns ) === '*' ) {
135  $this->fetchColumns = $columns;
136  } else {
137  $this->fetchColumns = array_unique( array_merge(
138  $this->primaryKey,
139  $columns
140  ) );
141  }
142  }
143 
150  public function extractPrimaryKeys( $row ) {
151  $pk = [];
152  foreach ( $this->primaryKey as $alias => $column ) {
153  $name = is_numeric( $alias ) ? $column : $alias;
154  $pk[$name] = $row->{$name};
155  }
156  return $pk;
157  }
158 
162  public function current() {
163  return $this->current;
164  }
165 
169  public function key() {
170  return $this->key;
171  }
172 
176  public function rewind() {
177  $this->key = -1; // self::next() will turn this into 0
178  $this->current = [];
179  $this->next();
180  }
181 
185  public function valid() {
186  return (bool)$this->current;
187  }
188 
192  public function hasChildren() {
193  return $this->current && count( $this->current );
194  }
195 
199  public function getChildren() {
200  return new NotRecursiveIterator( new ArrayIterator( $this->current ) );
201  }
202 
206  public function next() {
207  $res = $this->db->select(
208  $this->table,
209  $this->fetchColumns,
210  $this->buildConditions(),
211  __METHOD__,
212  [
213  'LIMIT' => $this->batchSize,
214  'ORDER BY' => $this->orderBy,
215  ] + $this->options,
216  $this->joinConditions
217  );
218 
219  // The iterator is converted to an array because in addition to
220  // returning it in self::current() we need to use the end value
221  // in self::buildConditions()
222  $this->current = iterator_to_array( $res );
223  $this->key++;
224  }
225 
238  protected function buildConditions() {
239  if ( !$this->current ) {
240  return $this->conditions;
241  }
242 
243  $maxRow = end( $this->current );
244  $maximumValues = [];
245  foreach ( $this->primaryKey as $alias => $column ) {
246  $name = is_numeric( $alias ) ? $column : $alias;
247  $maximumValues[$column] = $this->db->addQuotes( $maxRow->{$name} );
248  }
249 
250  $pkConditions = [];
251  // For example: If we have 3 primary keys
252  // first run through will generate
253  // col1 = 4 AND col2 = 7 AND col3 > 1
254  // second run through will generate
255  // col1 = 4 AND col2 > 7
256  // and the final run through will generate
257  // col1 > 4
258  while ( $maximumValues ) {
259  $pkConditions[] = $this->buildGreaterThanCondition( $maximumValues );
260  array_pop( $maximumValues );
261  }
262 
263  $conditions = $this->conditions;
264  $conditions[] = sprintf( '( %s )', implode( ' ) OR ( ', $pkConditions ) );
265 
266  return $conditions;
267  }
268 
281  protected function buildGreaterThanCondition( array $quotedMaximumValues ) {
282  $keys = array_keys( $quotedMaximumValues );
283  $lastColumn = end( $keys );
284  $lastValue = array_pop( $quotedMaximumValues );
285  $conditions = [];
286  foreach ( $quotedMaximumValues as $column => $value ) {
287  $conditions[] = "$column = $value";
288  }
289  $conditions[] = "$lastColumn > $lastValue";
290 
291  return implode( ' AND ', $conditions );
292  }
293 }
setFetchColumns(array $columns)
the array() calling protocol came about after MediaWiki 1.4rc1.
extractPrimaryKeys($row)
Extracts the primary key(s) from a database row.
$value
array $options
Additional query options.
integer $key
key 0-indexed number of pages fetched since self::reset()
We ve cleaned up the code here by removing clumps of infrequently used code and moving them off somewhere else It s much easier for someone working with this code to see what s _really_ going and make changes or fix bugs In we can take all the code that deals with the little used title reversing options(say) and put it in one place.Instead of having little title-reversing if-blocks spread all over the codebase in showAnArticle
next()
Fetch the next set of rows from the database.
buildConditions()
Uses the primary key list and the maximal result row from the previous iteration to build an SQL cond...
addJoinConditions(array $conditions)
design txt This is a brief overview of the new design More thorough and up to date information is available on the documentation wiki at etc Handles the details of getting and saving to the user table of the and dealing with sessions and cookies OutputPage Encapsulates the entire HTML page that will be sent in response to any server request It is used by calling its functions to add in any and then calling but I prefer the flexibility This should also do the output encoding The system allocates a global one in $wgOut Title Represents the title of an and does all the work of translating among various forms such as plain database key
Definition: design.txt:25
$res
Definition: database.txt:21
Apache License January AND DISTRIBUTION Definitions License shall mean the terms and conditions for and distribution as defined by Sections through of this document Licensor shall mean the copyright owner or entity authorized by the copyright owner that is granting the License Legal Entity shall mean the union of the acting entity and all other entities that control are controlled by or are under common control with that entity For the purposes of this definition control direct or to cause the direction or management of such whether by contract or including but not limited to software source documentation and configuration files Object form shall mean any form resulting from mechanical transformation or translation of a Source including but not limited to compiled object generated and conversions to other media types Work shall mean the work of whether in Source or Object made available under the as indicated by a copyright notice that is included in or attached to the whether in Source or Object that is based or other modifications as a an original work of authorship For the purposes of this Derivative Works shall not include works that remain separable or merely the Work and Derivative Works thereof Contribution shall mean any work of including the original version of the Work and any modifications or additions to that Work or Derivative Works that is intentionally submitted to Licensor for inclusion in the Work by the copyright owner or by an individual or Legal Entity authorized to submit on behalf of the copyright owner For the purposes of this submitted means any form of or written communication sent to the Licensor or its including but not limited to communication on electronic mailing source code control and issue tracking systems that are managed or on behalf the Licensor for the purpose of discussing and improving the but excluding communication that is conspicuously marked or otherwise designated in writing by the copyright owner as Not a Contribution Contributor shall mean Licensor and any individual or Legal Entity on behalf of whom a Contribution has been received by Licensor and subsequently incorporated within the Work Grant of Copyright License Subject to the terms and conditions of this each Contributor hereby grants to You a non no royalty irrevocable copyright license to prepare Derivative Works publicly publicly and distribute the Work and such Derivative Works in Source or Object form Grant of Patent License Subject to the terms and conditions of this each Contributor hereby grants to You a non no royalty have offer to and otherwise transfer the where such license applies only to those patent claims licensable by such Contributor that are necessarily infringed by their then any patent licenses granted to You under this License for that Work shall terminate as of the date such litigation is filed Redistribution You may reproduce and distribute copies of the Work or Derivative Works thereof in any with or without and in Source or Object provided that You meet the following conditions
to add to the query
This document is intended to provide useful advice for parties seeking to redistribute MediaWiki to end users It s targeted particularly at maintainers for Linux since it s been observed that distribution packages of MediaWiki often break We ve consistently had to recommend that users seeking support use official tarballs instead of their distribution s and this often solves whatever problem the user is having It would be nice if this could such as
Definition: distributors.txt:9
rewind()
Reset the iterator to the begining of the table.
injection txt This is an overview of how MediaWiki makes use of dependency injection The design described here grew from the discussion of RFC T384 The term dependency this means that anything an object needs to operate should be injected from the the object itself should only know narrow no concrete implementation of the logic it relies on The requirement to inject everything typically results in an architecture that based on two main types of and essentially stateless service objects that use other service objects to operate on the value objects As of the beginning MediaWiki is only starting to use the DI approach Much of the code still relies on global state or direct resulting in a highly cyclical dependency which acts as the top level factory for services in MediaWiki which can be used to gain access to default instances of various services MediaWikiServices however also allows new services to be defined and default services to be redefined Services are defined or redefined by providing a callback the instantiator that will return a new instance of the service When it will create an instance of MediaWikiServices and populate it with the services defined in the files listed by thereby bootstrapping the DI framework Per $wgServiceWiringFiles lists includes ServiceWiring php
Definition: injection.txt:35
deferred txt A few of the database updates required by various functions here can be deferred until after the result page is displayed to the user For updating the view updating the linked to tables after a etc PHP does not yet have any way to tell the server to actually return and disconnect while still running these but it might have such a feature in the future We handle these by creating a deferred update object and putting those objects on a global then executing the whole list after the page is displayed We don t do anything smart like collating updates to the same table or such because the list is almost always going to have just one item on if so it s not worth the trouble Since there is a job queue in the jobs table
Definition: deferred.txt:11
__construct(IDatabase $db, $table, $primaryKey, $batchSize)
addOptions(array $options)
buildGreaterThanCondition(array $quotedMaximumValues)
Given an array of column names and their maximum value generate an SQL condition where all keys excep...
Basic database interface for live and lazy-loaded relation database handles.
Definition: IDatabase.php:34
addConditions(array $conditions)
Allows to change the fields on the form that will be generated $name
Definition: hooks.txt:300