includes/libs/rdbms/database/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 ) || !strlen( $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 ) || !strlen( $schema ) ) ) {
  50                         throw new InvalidArgumentException( "Schema must be null or a non-empty string." );
  51                 }
  52                 $this->schema = $schema;
  53                 if ( !is_string( $prefix ) ) {
  54                         throw new InvalidArgumentException( "Prefix must be a string." );
  55                 }
  56                 $this->prefix = $prefix;
  57         }
  58
  59         /**
  60          * @param DatabaseDomain|string $domain Result of DatabaseDomain::toString()
  61          * @return DatabaseDomain
  62          */
  63         public static function newFromId( $domain ) {
  64                 if ( $domain instanceof self ) {
  65                         return $domain;
  66                 }
  67
  68                 $parts = array_map( [ __CLASS__, 'decode' ], explode( '-', $domain ) );
  69
  70                 $schema = null;
  71                 $prefix = '';
  72
  73                 if ( count( $parts ) == 1 ) {
  74                         $database = $parts[0];
  75                 } elseif ( count( $parts ) == 2 ) {
  76                         list( $database, $prefix ) = $parts;
  77                 } elseif ( count( $parts ) == 3 ) {
  78                         list( $database, $schema, $prefix ) = $parts;
  79                 } else {
  80                         throw new InvalidArgumentException( "Domain has too few or too many parts." );
  81                 }
  82
  83                 if ( $database === '' ) {
  84                         $database = null;
  85                 }
  86
  87                 if ( $schema === '' ) {
  88                         $schema = null;
  89                 }
  90
  91                 return new self( $database, $schema, $prefix );
  92         }
  93
  94         /**
  95          * @return DatabaseDomain
  96          */
  97         public static function newUnspecified() {
  98                 return new self( null, null, '' );
  99         }
 100
 101         /**
 102          * @param DatabaseDomain|string $other
 103          * @return bool Whether the domain instances are the same by value
 104          */
 105         public function equals( $other ) {
 106                 if ( $other instanceof self ) {
 107                         return (
 108                                 $this->database === $other->database &&
 109                                 $this->schema === $other->schema &&
 110                                 $this->prefix === $other->prefix
 111                         );
 112                 }
 113
 114                 return ( $this->getId() === $other );
 115         }
 116
 117         /**
 118          * Check whether the domain $other meets the specifications of this domain
 119          *
 120          * If this instance has a null database specifier, then $other can have any database
 121          * specified, including the null, and likewise if the schema specifier is null. This
 122          * is not transitive like equals() since a domain that explicitly wants a certain
 123          * database or schema cannot be satisfied by one of another (nor null). If the prefix
 124          * is empty and the DB and schema are both null, then the entire domain is considered
 125          * unspecified, and any prefix of $other is considered compatible.
 126          *
 127          * @param DatabaseDomain|string $other
 128          * @return bool
 129          * @since 1.32
 130          */
 131         public function isCompatible( $other ) {
 132                 if ( $this->isUnspecified() ) {
 133                         return true; // even the prefix doesn't matter
 134                 }
 135
 136                 $other = ( $other instanceof self ) ? $other : self::newFromId( $other );
 137
 138                 return (
 139                         ( $this->database === $other->database || $this->database === null ) &&
 140                         ( $this->schema === $other->schema || $this->schema === null ) &&
 141                         $this->prefix === $other->prefix
 142                 );
 143         }
 144
 145         /**
 146          * @return bool
 147          * @since 1.32
 148          */
 149         public function isUnspecified() {
 150                 return (
 151                         $this->database === null && $this->schema === null && $this->prefix === ''
 152                 );
 153         }
 154
 155         /**
 156          * @return string|null Database name
 157          */
 158         public function getDatabase() {
 159                 return $this->database;
 160         }
 161
 162         /**
 163          * @return string|null Database schema
 164          */
 165         public function getSchema() {
 166                 return $this->schema;
 167         }
 168
 169         /**
 170          * @return string Table prefix
 171          */
 172         public function getTablePrefix() {
 173                 return $this->prefix;
 174         }
 175
 176         /**
 177          * @return string
 178          */
 179         public function getId() {
 180                 if ( $this->equivalentString === null ) {
 181                         $this->equivalentString = $this->convertToString();
 182                 }
 183
 184                 return $this->equivalentString;
 185         }
 186
 187         /**
 188          * @return string
 189          */
 190         private function convertToString() {
 191                 $parts = [ $this->database ];
 192                 if ( $this->schema !== null ) {
 193                         $parts[] = $this->schema;
 194                 }
 195                 if ( $this->prefix != '' || $this->schema !== null ) {
 196                         // If there is a schema, then we need the prefix to disambiguate.
 197                         // For engines like Postgres that use schemas, this awkwardness is hopefully
 198                         // avoided since it is easy to have one DB per server (to avoid having many users)
 199                         // and use schema/prefix to have wiki farms. For example, a domain schemes could be
 200                         // wiki-<project>-<language>, e.g. "wiki-fitness-es"/"wiki-sports-fr"/"wiki-news-en".
 201                         $parts[] = $this->prefix;
 202                 }
 203
 204                 return implode( '-', array_map( [ __CLASS__, 'encode' ], $parts ) );
 205         }
 206
 207         private static function encode( $decoded ) {
 208                 $encoded = '';
 209
 210                 $length = strlen( $decoded );
 211                 for ( $i = 0; $i < $length; ++$i ) {
 212                         $char = $decoded[$i];
 213                         if ( $char === '-' ) {
 214                                 $encoded .= '?h';
 215                         } elseif ( $char === '?' ) {
 216                                 $encoded .= '??';
 217                         } else {
 218                                 $encoded .= $char;
 219                         }
 220                 }
 221
 222                 return $encoded;
 223         }
 224
 225         private static function decode( $encoded ) {
 226                 $decoded = '';
 227
 228                 $length = strlen( $encoded );
 229                 for ( $i = 0; $i < $length; ++$i ) {
 230                         $char = $encoded[$i];
 231                         if ( $char === '?' ) {
 232                                 $nextChar = isset( $encoded[$i + 1] ) ? $encoded[$i + 1] : null;
 233                                 if ( $nextChar === 'h' ) {
 234                                         $decoded .= '-';
 235                                         ++$i;
 236                                 } elseif ( $nextChar === '?' ) {
 237                                         $decoded .= '?';
 238                                         ++$i;
 239                                 } else {
 240                                         $decoded .= $char;
 241                                 }
 242                         } else {
 243                                 $decoded .= $char;
 244                         }
 245                 }
 246
 247                 return $decoded;
 248         }
 249
 250         /**
 251          * @return string
 252          */
 253         function __toString() {
 254                 return $this->getId();
 255         }
 256 }