+++ /dev/null
-<?php
-/**
- * This class stores an arbitrary value along with its dependencies.
- * Users should typically only use DependencyWrapper::getValueFromCache(),
- * rather than instantiating one of these objects directly.
- * @ingroup Cache
- */
-
-class DependencyWrapper {
- var $value;
- var $deps;
-
- /**
- * Create an instance.
- * @param $value Mixed: the user-supplied value
- * @param $deps Mixed: a dependency or dependency array. All dependencies
- * must be objects implementing CacheDependency.
- */
- function __construct( $value = false, $deps = array() ) {
- $this->value = $value;
-
- if ( !is_array( $deps ) ) {
- $deps = array( $deps );
- }
-
- $this->deps = $deps;
- }
-
- /**
- * Returns true if any of the dependencies have expired
- */
- function isExpired() {
- foreach ( $this->deps as $dep ) {
- if ( $dep->isExpired() ) {
- return true;
- }
- }
-
- return false;
- }
-
- /**
- * Initialise dependency values in preparation for storing. This must be
- * called before serialization.
- */
- function initialiseDeps() {
- foreach ( $this->deps as $dep ) {
- $dep->loadDependencyValues();
- }
- }
-
- /**
- * Get the user-defined value
- */
- function getValue() {
- return $this->value;
- }
-
- /**
- * Store the wrapper to a cache
- */
- function storeToCache( $cache, $key, $expiry = 0 ) {
- $this->initialiseDeps();
- $cache->set( $key, $this, $expiry );
- }
-
- /**
- * Attempt to get a value from the cache. If the value is expired or missing,
- * it will be generated with the callback function (if present), and the newly
- * calculated value will be stored to the cache in a wrapper.
- *
- * @param $cache Object: a cache object such as $wgMemc
- * @param $key String: the cache key
- * @param $expiry Integer: the expiry timestamp or interval in seconds
- * @param $callback Mixed: the callback for generating the value, or false
- * @param $callbackParams Array: the function parameters for the callback
- * @param $deps Array: the dependencies to store on a cache miss. Note: these
- * are not the dependencies used on a cache hit! Cache hits use the stored
- * dependency array.
- *
- * @return mixed The value, or null if it was not present in the cache and no
- * callback was defined.
- */
- static function getValueFromCache( $cache, $key, $expiry = 0, $callback = false,
- $callbackParams = array(), $deps = array() )
- {
- $obj = $cache->get( $key );
-
- if ( is_object( $obj ) && $obj instanceof DependencyWrapper && !$obj->isExpired() ) {
- $value = $obj->value;
- } elseif ( $callback ) {
- $value = call_user_func_array( $callback, $callbackParams );
- # Cache the newly-generated value
- $wrapper = new DependencyWrapper( $value, $deps );
- $wrapper->storeToCache( $cache, $key, $expiry );
- } else {
- $value = null;
- }
-
- return $value;
- }
-}
-
-/**
- * @ingroup Cache
- */
-abstract class CacheDependency {
- /**
- * Returns true if the dependency is expired, false otherwise
- */
- abstract function isExpired();
-
- /**
- * Hook to perform any expensive pre-serialize loading of dependency values.
- */
- function loadDependencyValues() { }
-}
-
-/**
- * @ingroup Cache
- */
-class FileDependency extends CacheDependency {
- var $filename, $timestamp;
-
- /**
- * Create a file dependency
- *
- * @param $filename String: the name of the file, preferably fully qualified
- * @param $timestamp Mixed: the unix last modified timestamp, or false if the
- * file does not exist. If omitted, the timestamp will be loaded from
- * the file.
- *
- * A dependency on a nonexistent file will be triggered when the file is
- * created. A dependency on an existing file will be triggered when the
- * file is changed.
- */
- function __construct( $filename, $timestamp = null ) {
- $this->filename = $filename;
- $this->timestamp = $timestamp;
- }
-
- function __sleep() {
- $this->loadDependencyValues();
- return array( 'filename', 'timestamp' );
- }
-
- function loadDependencyValues() {
- if ( is_null( $this->timestamp ) ) {
- if ( !file_exists( $this->filename ) ) {
- # Dependency on a non-existent file
- # This is a valid concept!
- $this->timestamp = false;
- } else {
- $this->timestamp = filemtime( $this->filename );
- }
- }
- }
-
- function isExpired() {
- if ( !file_exists( $this->filename ) ) {
- if ( $this->timestamp === false ) {
- # Still nonexistent
- return false;
- } else {
- # Deleted
- wfDebug( "Dependency triggered: {$this->filename} deleted.\n" );
- return true;
- }
- } else {
- $lastmod = filemtime( $this->filename );
- if ( $lastmod > $this->timestamp ) {
- # Modified or created
- wfDebug( "Dependency triggered: {$this->filename} changed.\n" );
- return true;
- } else {
- # Not modified
- return false;
- }
- }
- }
-}
-
-/**
- * @ingroup Cache
- */
-class TitleDependency extends CacheDependency {
- var $titleObj;
- var $ns, $dbk;
- var $touched;
-
- /**
- * Construct a title dependency
- * @param $title Title
- */
- function __construct( Title $title ) {
- $this->titleObj = $title;
- $this->ns = $title->getNamespace();
- $this->dbk = $title->getDBkey();
- }
-
- function loadDependencyValues() {
- $this->touched = $this->getTitle()->getTouched();
- }
-
- /**
- * Get rid of bulky Title object for sleep
- */
- function __sleep() {
- return array( 'ns', 'dbk', 'touched' );
- }
-
- function getTitle() {
- if ( !isset( $this->titleObj ) ) {
- $this->titleObj = Title::makeTitle( $this->ns, $this->dbk );
- }
-
- return $this->titleObj;
- }
-
- function isExpired() {
- $touched = $this->getTitle()->getTouched();
-
- if ( $this->touched === false ) {
- if ( $touched === false ) {
- # Still missing
- return false;
- } else {
- # Created
- return true;
- }
- } elseif ( $touched === false ) {
- # Deleted
- return true;
- } elseif ( $touched > $this->touched ) {
- # Updated
- return true;
- } else {
- # Unmodified
- return false;
- }
- }
-}
-
-/**
- * @ingroup Cache
- */
-class TitleListDependency extends CacheDependency {
- var $linkBatch;
- var $timestamps;
-
- /**
- * Construct a dependency on a list of titles
- */
- function __construct( LinkBatch $linkBatch ) {
- $this->linkBatch = $linkBatch;
- }
-
- function calculateTimestamps() {
- # Initialise values to false
- $timestamps = array();
-
- foreach ( $this->getLinkBatch()->data as $ns => $dbks ) {
- if ( count( $dbks ) > 0 ) {
- $timestamps[$ns] = array();
-
- foreach ( $dbks as $dbk => $value ) {
- $timestamps[$ns][$dbk] = false;
- }
- }
- }
-
- # Do the query
- if ( count( $timestamps ) ) {
- $dbr = wfGetDB( DB_SLAVE );
- $where = $this->getLinkBatch()->constructSet( 'page', $dbr );
- $res = $dbr->select(
- 'page',
- array( 'page_namespace', 'page_title', 'page_touched' ),
- $where,
- __METHOD__
- );
-
- foreach ( $res as $row ) {
- $timestamps[$row->page_namespace][$row->page_title] = $row->page_touched;
- }
- }
-
- return $timestamps;
- }
-
- function loadDependencyValues() {
- $this->timestamps = $this->calculateTimestamps();
- }
-
- function __sleep() {
- return array( 'timestamps' );
- }
-
- function getLinkBatch() {
- if ( !isset( $this->linkBatch ) ) {
- $this->linkBatch = new LinkBatch;
- $this->linkBatch->setArray( $this->timestamps );
- }
- return $this->linkBatch;
- }
-
- function isExpired() {
- $newTimestamps = $this->calculateTimestamps();
-
- foreach ( $this->timestamps as $ns => $dbks ) {
- foreach ( $dbks as $dbk => $oldTimestamp ) {
- $newTimestamp = $newTimestamps[$ns][$dbk];
-
- if ( $oldTimestamp === false ) {
- if ( $newTimestamp === false ) {
- # Still missing
- } else {
- # Created
- return true;
- }
- } elseif ( $newTimestamp === false ) {
- # Deleted
- return true;
- } elseif ( $newTimestamp > $oldTimestamp ) {
- # Updated
- return true;
- } else {
- # Unmodified
- }
- }
- }
-
- return false;
- }
-}
-
-/**
- * @ingroup Cache
- */
-class GlobalDependency extends CacheDependency {
- var $name, $value;
-
- function __construct( $name ) {
- $this->name = $name;
- $this->value = $GLOBALS[$name];
- }
-
- function isExpired() {
- return $GLOBALS[$this->name] != $this->value;
- }
-}
-
-/**
- * @ingroup Cache
- */
-class ConstantDependency extends CacheDependency {
- var $name, $value;
-
- function __construct( $name ) {
- $this->name = $name;
- $this->value = constant( $name );
- }
-
- function isExpired() {
- return constant( $this->name ) != $this->value;
- }
-}
scripts.mit.edu / autoinstallsdev / mediawiki.git / blobdiff