3 * Efficient concatenated text storage.
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 2 of the License, or
8 * (at your option) any later version.
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
15 * You should have received a copy of the GNU General Public License along
16 * with this program; if not, write to the Free Software Foundation, Inc.,
17 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
18 * http://www.gnu.org/copyleft/gpl.html
24 * Pointer object for an item within a CGZ blob stored in the text table.
26 class HistoryBlobStub
{
28 * @var array One-step cache variable to hold base blobs; operations that
29 * pull multiple revisions may often pull multiple times from the same
30 * blob. By keeping the last-used one open, we avoid redundant
31 * unserialization and decompression overhead.
33 protected static $blobCache = [];
45 * @param string $hash The content hash of the text
46 * @param int $oldid The old_id for the CGZ object
48 function __construct( $hash = '', $oldid = 0 ) {
53 * Sets the location (old_id) of the main object to which this object
57 function setLocation( $id ) {
62 * Sets the location (old_id) of the referring object
65 function setReferrer( $id ) {
70 * Gets the location of the referring object
73 function getReferrer() {
78 * @return string|false
81 if ( isset( self
::$blobCache[$this->mOldId
] ) ) {
82 $obj = self
::$blobCache[$this->mOldId
];
84 $dbr = wfGetDB( DB_REPLICA
);
85 $row = $dbr->selectRow(
87 [ 'old_flags', 'old_text' ],
88 [ 'old_id' => $this->mOldId
]
95 $flags = explode( ',', $row->old_flags
);
96 if ( in_array( 'external', $flags ) ) {
97 $url = $row->old_text
;
98 $parts = explode( '://', $url, 2 );
99 if ( !isset( $parts[1] ) ||
$parts[1] == '' ) {
102 $row->old_text
= ExternalStore
::fetchFromURL( $url );
106 if ( !in_array( 'object', $flags ) ) {
110 if ( in_array( 'gzip', $flags ) ) {
111 // This shouldn't happen, but a bug in the compress script
112 // may at times gzip-compress a HistoryBlob object row.
113 $obj = unserialize( gzinflate( $row->old_text
) );
115 $obj = unserialize( $row->old_text
);
118 if ( !is_object( $obj ) ) {
119 // Correct for old double-serialization bug.
120 $obj = unserialize( $obj );
123 // Save this item for reference; if pulling many
124 // items in a row we'll likely use it again.
126 self
::$blobCache = [ $this->mOldId
=> $obj ];
129 return $obj->getItem( $this->mHash
);
133 * Get the content hash
142 // phpcs:ignore Generic.CodeAnalysis.UnconditionalIfStatement.Found
144 // Blobs generated by MediaWiki < 1.5 on PHP 4 were serialized with the
145 // class name coerced to lowercase. We can improve efficiency by adding
146 // autoload entries for the lowercase variants of these classes (T166759).
147 // The code below is never executed, but it is picked up by the AutoloadGenerator
148 // parser, which scans for class_alias() calls.
149 class_alias( HistoryBlobStub
::class, 'historyblobstub' );