includes/Revision/RevisionSlots.php
<?php
/**
* Value object representing the set of slots belonging to a revision.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
* http://www.gnu.org/copyleft/gpl.html
*
* @file
*/
namespace MediaWiki\Revision;
use Content;
use Wikimedia\Assert\Assert;
use Wikimedia\NonSerializable\NonSerializableTrait;
/**
* Value object representing the set of slots belonging to a revision.
*
* @note RevisionSlots provides "raw" access to the slots and does not apply audience checks.
* If audience checks are desired, use RevisionRecord::getSlot() or RevisionRecord::getContent()
* instead.
*
* @newable
*
* @since 1.31
* @since 1.32 Renamed from MediaWiki\Storage\RevisionSlots
*/
class RevisionSlots {
use NonSerializableTrait;
/** @var SlotRecord[]|callable */
protected $slots;
/**
* @stable to call.
*
* @param SlotRecord[]|callable $slots SlotRecords,
* or a callback that returns such a structure.
*/
public function __construct( $slots ) {
Assert::parameterType( [ 'array', 'callable' ], $slots, '$slots' );
if ( is_callable( $slots ) ) {
$this->slots = $slots;
} else {
$this->setSlotsInternal( $slots );
}
}
/**
* @param SlotRecord[] $slots
*/
private function setSlotsInternal( array $slots ): void {
Assert::parameterElementType( SlotRecord::class, $slots, '$slots' );
$this->slots = [];
// re-key the slot array
foreach ( $slots as $slot ) {
$role = $slot->getRole();
$this->slots[$role] = $slot;
}
}
/**
* Returns the Content of the given slot.
* Call getSlotNames() to get a list of available slots.
*
* Note that for mutable Content objects, each call to this method will return a
* fresh clone.
*
* @see SlotRecord::getContent()
*
* @param string $role The role name of the desired slot
*
* @throws RevisionAccessException if the slot does not exist or slot data
* could not be lazy-loaded. See SlotRecord::getContent() for details.
* @return Content
*/
public function getContent( $role ): Content {
// Return a copy to be safe. Immutable content objects return $this from copy().
return $this->getSlot( $role )->getContent()->copy();
}
/**
* Returns the SlotRecord of the given slot.
* Call getSlotNames() to get a list of available slots.
*
* @param string $role The role name of the desired slot
*
* @throws RevisionAccessException if the slot does not exist or slot data
* could not be lazy-loaded.
* @return SlotRecord
*/
public function getSlot( $role ): SlotRecord {
$slots = $this->getSlots();
if ( isset( $slots[$role] ) ) {
return $slots[$role];
} else {
throw new RevisionAccessException(
'No such slot: {role}',
[ 'role' => $role ]
);
}
}
/**
* Returns whether the given slot is set.
*
* @param string $role The role name of the desired slot
*
* @return bool
*/
public function hasSlot( $role ): bool {
$slots = $this->getSlots();
return isset( $slots[$role] );
}
/**
* Returns the slot names (roles) of all slots present in this revision.
* getContent() will succeed only for the names returned by this method.
*
* @return string[]
*/
public function getSlotRoles(): array {
$slots = $this->getSlots();
return array_keys( $slots );
}
/**
* Computes the total nominal size of the revision's slots, in bogo-bytes.
*
* @warning This is potentially expensive! It may cause some slots' content to be loaded
* and deserialized.
*
* @return int
*/
public function computeSize(): int {
return array_reduce( $this->getPrimarySlots(), static function ( $accu, SlotRecord $slot ) {
return $accu + $slot->getSize();
}, 0 );
}
/**
* Returns an associative array that maps role names to SlotRecords. Each SlotRecord
* represents the content meta-data of a slot, together they define the content of
* a revision.
*
* @note This may cause the content meta-data for the revision to be lazy-loaded.
*
* @return SlotRecord[] revision slot/content rows, keyed by slot role name.
*/
public function getSlots(): array {
if ( is_callable( $this->slots ) ) {
$slots = call_user_func( $this->slots );
Assert::postcondition(
is_array( $slots ),
'Slots info callback should return an array of objects'
);
$this->setSlotsInternal( $slots );
}
return $this->slots;
}
/**
* Computes the combined hash of the revisions's slots.
*
* @note For backwards compatibility, the combined hash of a single slot
* is that slot's hash. For consistency, the combined hash of an empty set of slots
* is the hash of the empty string.
*
* @warning This is potentially expensive! It may cause some slots' content to be loaded
* and deserialized, then re-serialized and hashed.
*
* @return string
*/
public function computeSha1(): string {
$slots = $this->getPrimarySlots();
ksort( $slots );
if ( !$slots ) {
return SlotRecord::base36Sha1( '' );
}
return array_reduce( $slots, static function ( $accu, SlotRecord $slot ) {
return $accu === null
? $slot->getSha1()
: SlotRecord::base36Sha1( $accu . $slot->getSha1() );
}, null );
}
/**
* Return all slots that belong to the revision they originate from (that is,
* they are not inherited from some other revision).
*
* @note This may cause the slot meta-data for the revision to be lazy-loaded.
*
* @return SlotRecord[]
*/
public function getOriginalSlots(): array {
return array_filter(
$this->getSlots(),
static function ( SlotRecord $slot ) {
return !$slot->isInherited();
}
);
}
/**
* Return all slots that are not originate in the revision they belong to (that is,
* they are inherited from some other revision).
*
* @note This may cause the slot meta-data for the revision to be lazy-loaded.
*
* @return SlotRecord[]
*/
public function getInheritedSlots(): array {
return array_filter(
$this->getSlots(),
static function ( SlotRecord $slot ) {
return $slot->isInherited();
}
);
}
/**
* Return all primary slots (those that are not derived).
*
* @return SlotRecord[]
* @since 1.36
*/
public function getPrimarySlots(): array {
return array_filter(
$this->getSlots(),
static function ( SlotRecord $slot ) {
return !$slot->isDerived();
}
);
}
/**
* Checks whether the other RevisionSlots instance has the same content
* as this instance. Note that this does not mean that the slots have to be the same:
* they could for instance belong to different revisions.
*
* @param RevisionSlots $other
*
* @return bool
*/
public function hasSameContent( RevisionSlots $other ): bool {
if ( $other === $this ) {
return true;
}
$aSlots = $this->getSlots();
$bSlots = $other->getSlots();
ksort( $aSlots );
ksort( $bSlots );
if ( array_keys( $aSlots ) !== array_keys( $bSlots ) ) {
return false;
}
foreach ( $aSlots as $role => $s ) {
$t = $bSlots[$role];
if ( !$s->hasSameContent( $t ) ) {
return false;
}
}
return true;
}
/**
* Find roles for which the $other RevisionSlots object has different content
* as this RevisionSlots object, including any roles that are present in one
* but not the other.
*
* @param RevisionSlots $other
*
* @return string[] a list of slot roles that are different.
*/
public function getRolesWithDifferentContent( RevisionSlots $other ): array {
if ( $other === $this ) {
return [];
}
$aSlots = $this->getSlots();
$bSlots = $other->getSlots();
ksort( $aSlots );
ksort( $bSlots );
$different = array_keys( array_merge(
array_diff_key( $aSlots, $bSlots ),
array_diff_key( $bSlots, $aSlots )
) );
/** @var SlotRecord[] $common */
$common = array_intersect_key( $aSlots, $bSlots );
foreach ( $common as $role => $s ) {
$t = $bSlots[$role];
if ( !$s->hasSameContent( $t ) ) {
$different[] = $role;
}
}
return $different;
}
}