47 $map = array_filter( $map,
function ( $w ) {
50 if ( !count( $map ) ) {
51 throw new UnexpectedValueException(
"Ring is empty or all weights are zero." );
53 $this->sourceMap = $map;
56 foreach ( $map
as $location => $weight ) {
57 $hashes[$location] = sha1( $location );
59 uksort( $map,
function ( $a, $b )
use (
$hashes ) {
63 $sum = array_sum( $map );
65 foreach ( $map
as $location => $weight ) {
66 $standardMap[$location] = (int)floor( $weight / $sum * self::RING_SIZE );
70 foreach ( $standardMap
as $location => $weight ) {
72 $this->ring[$location] = [ $index, $index + $weight ];
101 $primaryLocation =
null;
102 $spot = hexdec( substr( sha1( $item ), 0, 7 ) );
103 foreach ( $this->ring
as $location => $range ) {
104 if ( count( $locations ) >= $limit ) {
109 if ( ( $range[0] <= $spot && $spot < $range[1] ) || $primaryLocation !==
null ) {
110 if ( $primaryLocation ===
null ) {
111 $primaryLocation = $location;
113 $locations[] = $location;
117 reset( $this->ring );
118 while ( count( $locations ) < $limit ) {
119 list( $location, ) = each( $this->ring );
120 if ( $location === $primaryLocation ) {
123 $locations[] = $location;
146 unset( $map[$location] );
148 return count( $map ) ?
new self( $map ) :
false;
159 if ( !isset( $this->sourceMap[$location] ) ) {
160 throw new UnexpectedValueException(
"No location '$location' in the ring." );
162 $expiry = time() + $ttl;
163 $this->liveRing =
null;
164 $this->ejectionExpiries[$location] = $expiry;
165 $this->ejectionNextExpiry = min( $expiry, $this->ejectionNextExpiry );
167 return ( count( $this->ejectionExpiries ) < count( $this->sourceMap ) );
178 if ( $this->liveRing ===
null || $this->ejectionNextExpiry <= $now ) {
179 $this->ejectionExpiries = array_filter(
180 $this->ejectionExpiries,
181 function ( $expiry )
use ( $now ) {
182 return ( $expiry > $now );
185 if ( count( $this->ejectionExpiries ) ) {
186 $map = array_diff_key( $this->sourceMap, $this->ejectionExpiries );
187 $this->liveRing = count( $map ) ?
new self( $map ) :
false;
189 $this->ejectionNextExpiry = min( $this->ejectionExpiries );
191 $this->liveRing = clone $this;
192 $this->liveRing->ejectionExpiries = [];
193 $this->liveRing->ejectionNextExpiry = INF;
194 $this->liveRing->liveRing =
null;
196 $this->ejectionNextExpiry = INF;
199 if ( !$this->liveRing ) {
200 throw new UnexpectedValueException(
"The live ring is currently empty." );
226 return $this->
getLiveRing()->getLocations( $item, $limit );
Apache License January AND DISTRIBUTION Definitions License shall mean the terms and conditions for use
Convenience class for weighted consistent hash rings.
getLiveLocations( $item, $limit)
Get the location of an item on the "live" ring, as well as the next locations.
Array $sourceMap
(location => weight)
getLiveLocationWeights()
Get the map of "live" locations to weight (ignores 0-weight items)
int $ejectionNextExpiry
UNIX timestamp.
getLiveLocation( $item)
Get the location of an item on the "live" ring.
newWithoutLocation( $location)
Get a new hash ring with a location removed from the ring.
getLocation( $item)
Get the location of an item on the ring.
getLocations( $item, $limit)
Get the location of an item on the ring, as well as the next locations.
Array $ejectionExpiries
(location => UNIX timestamp)
Array $ring
(location => (start, end))
getLocationWeights()
Get the map of locations to weight (ignores 0-weight items)
getLiveRing()
Get the "live" hash ring (which does not include ejected locations)
ejectFromLiveRing( $location, $ttl)
Remove a location from the "live" hash ring.
deferred txt A few of the database updates required by various functions here can be deferred until after the result page is displayed to the user For updating the view updating the linked to tables after a etc PHP does not yet have any way to tell the server to actually return and disconnect while still running these but it might have such a feature in the future We handle these by creating a deferred update object and putting those objects on a global list
design txt This is a brief overview of the new design More thorough and up to date information is available on the documentation wiki at etc Handles the details of getting and saving to the user table of the and dealing with sessions and cookies OutputPage Encapsulates the entire HTML page that will be sent in response to any server request It is used by calling its functions to add in any and then calling but I prefer the flexibility This should also do the output encoding The system allocates a global one in $wgOut Title Represents the title of an and does all the work of translating among various forms such as plain database key
This document is intended to provide useful advice for parties seeking to redistribute MediaWiki to end users It s targeted particularly at maintainers for Linux since it s been observed that distribution packages of MediaWiki often break We ve consistently had to recommend that users seeking support use official tarballs instead of their distribution s and this often solves whatever problem the user is having It would be nice if this could such as
the array() calling protocol came about after MediaWiki 1.4rc1.
injection txt This is an overview of how MediaWiki makes use of dependency injection The design described here grew from the discussion of RFC T384 The term dependency this means that anything an object needs to operate should be injected from the the object itself should only know narrow no concrete implementation of the logic it relies on The requirement to inject everything typically results in an architecture that based on two main types of and essentially stateless service objects that use other service objects to operate on the value objects As of the beginning MediaWiki is only starting to use the DI approach Much of the code still relies on global state or direct resulting in a highly cyclical dependency which acts as the top level factory for services in MediaWiki which can be used to gain access to default instances of various services MediaWikiServices however also allows new services to be defined and default services to be redefined Services are defined or redefined by providing a callback the instantiator that will return a new instance of the service When it will create an instance of MediaWikiServices and populate it with the services defined in the files listed by thereby bootstrapping the DI framework Per $wgServiceWiringFiles lists includes ServiceWiring php