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LCStoreDB.php
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1 <?php
24 use Wikimedia\ScopedCallback;
25 
31 class LCStoreDB implements LCStore {
33  private $code;
35  private $server;
36 
38  private $batch = [];
39 
41  private $dbw;
43  private $writesDone = false;
45  private $readOnly = false;
46 
47  public function __construct( $params ) {
48  $this->server = $params['server'] ?? [];
49  }
50 
51  public function get( $code, $key ) {
52  if ( $this->server || $this->writesDone ) {
53  // If a server configuration map is specified, always used that connection
54  // for reads and writes. Otherwise, if writes occurred in finishWrite(), make
55  // sure those changes are always visible.
56  $db = $this->getWriteConnection();
57  } else {
58  $db = wfGetDB( DB_REPLICA );
59  }
60 
61  $value = $db->selectField(
62  'l10n_cache',
63  'lc_value',
64  [ 'lc_lang' => $code, 'lc_key' => $key ],
65  __METHOD__
66  );
67 
68  return ( $value !== false ) ? unserialize( $db->decodeBlob( $value ) ) : null;
69  }
70 
71  public function startWrite( $code ) {
72  if ( $this->readOnly ) {
73  return;
74  } elseif ( !$code ) {
75  throw new MWException( __METHOD__ . ": Invalid language \"$code\"" );
76  }
77 
78  $dbw = $this->getWriteConnection();
79  $this->readOnly = $dbw->isReadOnly();
80 
81  $this->code = $code;
82  $this->batch = [];
83  }
84 
85  public function finishWrite() {
86  if ( $this->readOnly ) {
87  return;
88  } elseif ( $this->code === null ) {
89  throw new MWException( __CLASS__ . ': must call startWrite() before finishWrite()' );
90  }
91 
92  $scope = Profiler::instance()->getTransactionProfiler()->silenceForScope();
93  $dbw = $this->getWriteConnection();
94  $dbw->startAtomic( __METHOD__ );
95  try {
96  $dbw->delete( 'l10n_cache', [ 'lc_lang' => $this->code ], __METHOD__ );
97  foreach ( array_chunk( $this->batch, 500 ) as $rows ) {
98  $dbw->insert( 'l10n_cache', $rows, __METHOD__ );
99  }
100  $this->writesDone = true;
101  } catch ( DBQueryError $e ) {
102  if ( $dbw->wasReadOnlyError() ) {
103  $this->readOnly = true; // just avoid site down time
104  } else {
105  throw $e;
106  }
107  }
108  $dbw->endAtomic( __METHOD__ );
109  ScopedCallback::consume( $scope );
110 
111  $this->code = null;
112  $this->batch = [];
113  }
114 
115  public function set( $key, $value ) {
116  if ( $this->readOnly ) {
117  return;
118  } elseif ( $this->code === null ) {
119  throw new MWException( __CLASS__ . ': must call startWrite() before set()' );
120  }
121 
122  $dbw = $this->getWriteConnection();
123 
124  $this->batch[] = [
125  'lc_lang' => $this->code,
126  'lc_key' => $key,
127  'lc_value' => $dbw->encodeBlob( serialize( $value ) )
128  ];
129  }
130 
134  private function getWriteConnection() {
135  if ( !$this->dbw ) {
136  if ( $this->server ) {
137  $dbFactory = MediaWikiServices::getInstance()->getDatabaseFactory();
138  $this->dbw = $dbFactory->create( $this->server['type'], $this->server );
139  if ( !$this->dbw ) {
140  throw new MWException( __CLASS__ . ': failed to obtain a DB connection' );
141  }
142  } else {
143  $this->dbw = wfGetDB( DB_PRIMARY );
144  }
145  }
146 
147  return $this->dbw;
148  }
149 }
wfGetDB( $db, $groups=[], $wiki=false)
Get a Database object.
LCStore implementation which uses the standard DB functions to store data.
Definition: LCStoreDB.php:31
finishWrite()
Finish a write transaction.
Definition: LCStoreDB.php:85
startWrite( $code)
Start a write transaction.
Definition: LCStoreDB.php:71
__construct( $params)
Definition: LCStoreDB.php:47
MediaWiki exception.
Definition: MWException.php:32
Service locator for MediaWiki core services.
static instance()
Singleton.
Definition: Profiler.php:108
Interface for the persistence layer of LocalisationCache.
Definition: LCStore.php:40
Basic database interface for live and lazy-loaded relation database handles.
Definition: IDatabase.php:36
endAtomic( $fname=__METHOD__)
Ends an atomic section of SQL statements.
delete( $table, $conds, $fname=__METHOD__)
Delete all rows in a table that match a condition.
insert( $table, $rows, $fname=__METHOD__, $options=[])
Insert row(s) into a table, in the provided order.
startAtomic( $fname=__METHOD__, $cancelable=self::ATOMIC_NOT_CANCELABLE)
Begin an atomic section of SQL statements.
encodeBlob( $b)
Some DBMSs have a special format for inserting into blob fields, they don't allow simple quoted strin...
wasReadOnlyError()
Determines if the last failure was due to the database being read-only.
const DB_REPLICA
Definition: defines.php:26
const DB_PRIMARY
Definition: defines.php:28