includes/libs/rdbms/database/domain/DatabaseDomain.php

   1 <?php
   2 /**
   3  * This program is free software; you can redistribute it and/or modify
   4  * it under the terms of the GNU General Public License as published by
   5  * the Free Software Foundation; either version 2 of the License, or
   6  * (at your option) any later version.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  11  * GNU General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License along
  14  * with this program; if not, write to the Free Software Foundation, Inc.,
  15  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  16  * http://www.gnu.org/copyleft/gpl.html
  17  *
  18  * @file
  19  * @ingroup Database
  20  */
  21 namespace Wikimedia\Rdbms;
  22
  23 use InvalidArgumentException;
  24
  25 /**
  26  * Class to handle database/prefix specification for IDatabase domains
  27  */
  28 class DatabaseDomain {
  29         /** @var string|null */
  30         private $database;
  31         /** @var string|null */
  32         private $schema;
  33         /** @var string */
  34         private $prefix;
  35
  36         /** @var string Cache of convertToString() */
  37         private $equivalentString;
  38
  39         /**
  40          * @param string|null $database Database name
  41          * @param string|null $schema Schema name
  42          * @param string $prefix Table prefix
  43          */
  44         public function __construct( $database, $schema, $prefix ) {
  45                 if ( $database !== null && ( !is_string( $database ) || $database === '' ) ) {
  46                         throw new InvalidArgumentException( 'Database must be null or a non-empty string.' );
  47                 }
  48                 $this->database = $database;
  49                 if ( $schema !== null && ( !is_string( $schema ) || $schema === '' ) ) {
  50                         throw new InvalidArgumentException( 'Schema must be null or a non-empty string.' );
  51                 } elseif ( $database === null && $schema !== null ) {
  52                         throw new InvalidArgumentException( 'Schema must be null if database is null.' );
  53                 }
  54                 $this->schema = $schema;
  55                 if ( !is_string( $prefix ) ) {
  56                         throw new InvalidArgumentException( 'Prefix must be a string.' );
  57                 } elseif ( $prefix !== '' && substr( $prefix, -1, 1 ) !== '_' ) {
  58                         throw new InvalidArgumentException( 'A non-empty prefix must end with "_".' );
  59                 }
  60                 $this->prefix = $prefix;
  61         }
  62
  63         /**
  64          * @param DatabaseDomain|string $domain Result of DatabaseDomain::toString()
  65          * @return DatabaseDomain
  66          */
  67         public static function newFromId( $domain ) {
  68                 if ( $domain instanceof self ) {
  69                         return $domain;
  70                 }
  71
  72                 $parts = array_map( [ __CLASS__, 'decode' ], explode( '-', $domain ) );
  73
  74                 $schema = null;
  75                 $prefix = '';
  76
  77                 if ( count( $parts ) == 1 ) {
  78                         $database = $parts[0];
  79                 } elseif ( count( $parts ) == 2 ) {
  80                         list( $database, $prefix ) = $parts;
  81                 } elseif ( count( $parts ) == 3 ) {
  82                         list( $database, $schema, $prefix ) = $parts;
  83                 } else {
  84                         throw new InvalidArgumentException( "Domain '$domain' has too few or too many parts." );
  85                 }
  86
  87                 if ( $database === '' ) {
  88                         $database = null;
  89                 }
  90
  91                 if ( $schema === '' ) {
  92                         $schema = null;
  93                 }
  94
  95                 return new self( $database, $schema, $prefix );
  96         }
  97
  98         /**
  99          * @return DatabaseDomain
 100          */
 101         public static function newUnspecified() {
 102                 return new self( null, null, '' );
 103         }
 104
 105         /**
 106          * @param DatabaseDomain|string $other
 107          * @return bool Whether the domain instances are the same by value
 108          */
 109         public function equals( $other ) {
 110                 if ( $other instanceof self ) {
 111                         return (
 112                                 $this->database === $other->database &&
 113                                 $this->schema === $other->schema &&
 114                                 $this->prefix === $other->prefix
 115                         );
 116                 }
 117
 118                 return ( $this->getId() === $other );
 119         }
 120
 121         /**
 122          * Check whether the domain $other meets the specifications of this domain
 123          *
 124          * If this instance has a null database specifier, then $other can have any database
 125          * specifier, including null. This is likewise true if the schema specifier is null.
 126          * This is not transitive like equals() since a domain that explicitly wants a certain
 127          * database or schema cannot be satisfied by one of another (nor null). If the prefix
 128          * is empty and the DB and schema are both null, then the entire domain is considered
 129          * unspecified, and any prefix of $other is considered compatible.
 130          *
 131          * @param DatabaseDomain|string $other
 132          * @return bool
 133          * @since 1.32
 134          */
 135         public function isCompatible( $other ) {
 136                 if ( $this->isUnspecified() ) {
 137                         return true; // even the prefix doesn't matter
 138                 }
 139
 140                 $other = self::newFromId( $other );
 141
 142                 return (
 143                         ( $this->database === $other->database || $this->database === null ) &&
 144                         ( $this->schema === $other->schema || $this->schema === null ) &&
 145                         $this->prefix === $other->prefix
 146                 );
 147         }
 148
 149         /**
 150          * @return bool
 151          * @since 1.32
 152          */
 153         public function isUnspecified() {
 154                 return (
 155                         $this->database === null && $this->schema === null && $this->prefix === ''
 156                 );
 157         }
 158
 159         /**
 160          * @return string|null Database name
 161          */
 162         public function getDatabase() {
 163                 return $this->database;
 164         }
 165
 166         /**
 167          * @return string|null Database schema
 168          */
 169         public function getSchema() {
 170                 return $this->schema;
 171         }
 172
 173         /**
 174          * @return string Table prefix
 175          */
 176         public function getTablePrefix() {
 177                 return $this->prefix;
 178         }
 179
 180         /**
 181          * @return string
 182          */
 183         public function getId() {
 184                 if ( $this->equivalentString === null ) {
 185                         $this->equivalentString = $this->convertToString();
 186                 }
 187
 188                 return $this->equivalentString;
 189         }
 190
 191         /**
 192          * @return string
 193          */
 194         private function convertToString() {
 195                 $parts = [ (string)$this->database ];
 196                 if ( $this->schema !== null ) {
 197                         $parts[] = $this->schema;
 198                 }
 199                 if ( $this->prefix != '' || $this->schema !== null ) {
 200                         // If there is a schema, then we need the prefix to disambiguate.
 201                         // For engines like Postgres that use schemas, this awkwardness is hopefully
 202                         // avoided since it is easy to have one DB per server (to avoid having many users)
 203                         // and use schema/prefix to have wiki farms. For example, a domain schemes could be
 204                         // wiki-<project>-<language>, e.g. "wiki-fitness-es"/"wiki-sports-fr"/"wiki-news-en".
 205                         $parts[] = $this->prefix;
 206                 }
 207
 208                 return implode( '-', array_map( [ __CLASS__, 'encode' ], $parts ) );
 209         }
 210
 211         private static function encode( $decoded ) {
 212                 $encoded = '';
 213
 214                 $length = strlen( $decoded );
 215                 for ( $i = 0; $i < $length; ++$i ) {
 216                         $char = $decoded[$i];
 217                         if ( $char === '-' ) {
 218                                 $encoded .= '?h';
 219                         } elseif ( $char === '?' ) {
 220                                 $encoded .= '??';
 221                         } else {
 222                                 $encoded .= $char;
 223                         }
 224                 }
 225
 226                 return $encoded;
 227         }
 228
 229         private static function decode( $encoded ) {
 230                 $decoded = '';
 231
 232                 $length = strlen( $encoded );
 233                 for ( $i = 0; $i < $length; ++$i ) {
 234                         $char = $encoded[$i];
 235                         if ( $char === '?' ) {
 236                                 $nextChar = $encoded[$i + 1] ?? null;
 237                                 if ( $nextChar === 'h' ) {
 238                                         $decoded .= '-';
 239                                         ++$i;
 240                                 } elseif ( $nextChar === '?' ) {
 241                                         $decoded .= '?';
 242                                         ++$i;
 243                                 } else {
 244                                         $decoded .= $char;
 245                                 }
 246                         } else {
 247                                 $decoded .= $char;
 248                         }
 249                 }
 250
 251                 return $decoded;
 252         }
 253
 254         /**
 255          * @return string
 256          */
 257         function __toString() {
 258                 return $this->getId();
 259         }
 260 }