internal package Foswiki::PageCache 
  internal package Foswiki::PageCache 
Interface to the caching infrastructure.
  ClassMethod new( $session ) → $object 
Construct a new page cache and a delegator.
  ObjectMethod genVariationKey() → $key 
Generate a key for the current webtopic being produced; this reads
information from the current session and url params, as follows:
    *  The server serving the request (HTTP_HOST)
    * The port number of the server serving the request (HTTP_PORT)
    * The language of the current session, if any
    * All session parameters EXCEPT:
          o Those starting with an underscore
          o VALIDATION
          o REMEMBER
          o FOSWIKISTRIKEONE.*
          o VALID_ACTIONS.*
          o BREADCRUMB_TRAIL
    * All HTTP request parameters EXCEPT:
          o All those starting with an underscore
          o refresh
          o foswiki_redirect_cache
          o logout
          o style.*
          o switch.*
          o topic
  ObjectMethod cachePage($contentType, $text) → $boolean 
Cache a html page. every page is stored in a page bucket
that contains all variations (stored for other users or other session
parameters) of this page, as well as dependency and expiration information
Note that the dependencies are fired in reverse order as the depending pages
have to notify this page if they changed. 
  ObjectMethod getPage($web, $topic) 
Retrieve a html page for the given web.topic from cache, using a variation
key based on the current session.
  ObjectMethod addDependency($web, $topic) 
Add a web.topic to the dependencies of the current page
  ObjectMethod getDependencies($web, $topic, $variationKey) → \@deps 
Return dependencies for a given web.topic
  ObjectMethod getRevDependencies($web, $topic) → \@deps 
Return reverse dependencies for a given web.topic (those topics that
depend on this topic)
  ObjectMethod getWebDependencies($web) → \@deps 
Returns dependencies that hold for all topics in a web. 
  ObjectMethod deletePage($web, $topic) 
Remove a page from the cache; this removes all of the information
that we have about this page 
  ObjectMethod fireDependency($web, $topic) 
Fire a dependency invalidating the related cache entries.
  ObjectMethod renderDirtyAreas($text) 
Extract dirty areas and render them; this happens after storing a 
page including the un-rendered dirty areas into the cache and after
retrieving it again.
  ObjectMethod finish() 
Break cyclic dependencies during destruction.