Package TWiki::Prefs::PrefsCache

The PrefsCache package holds a cache of topics that have been read in, using the TopicPrefs class. These functions manage that cache.

We maintain 2 hashes of values:

  • {locals} Contains all locals at this level. Locals are values that only apply when the current topic is the topic where the local is defined. The variable names are decorated with the locality where they apply.
  • {values} contains all sets, locals, and all values inherited from the parent level

As each cache level is built, the values are copied down from the parent cache level. This sounds monstrously inefficient, but in fact perl does this a lot better than doing a multi-level lookup when a value is referenced. This is especially important when many prefs lookups may be done in a session, for example when searching.

On this page:

ClassMethod new ($prefs,$parent,$type,$web,$topic,$prefix)

Creates a new Prefs object.

  • $prefs - controlling TWiki::Prefs object
  • $parent - the PrefsCache object to use to initialise values from
  • $type - Type of prefs object to create, see notes.
  • $web - web containing topic to load from (required is $topic is set)
  • $topic - topic to load from
  • $prefix - key prefix for all preferences (used for plugins)
If the specified topic is not found, returns an empty object.

ObjectMethod finish ()

Break circular references.

ObjectMethod finalise ($parent)

Finalise preferences in this cache, by freezing any preferences listed in FINALPREFERENCES at their current value.

  • $parent = object that supports getPreferenceValue

ObjectMethod loadPrefsFromTopic ($web,$topic,$keyPrefix)

Loads preferences from a topic. All settings loaded are prefixed with the key prefix (default '').

ObjectMethod loadPrefsFromText ($text,$meta,$web,$topic)

Loads preferences from text and optional metadata. All settings loaded are prefixed with the key prefix (default ''). If $meta is defined, then metadata will be taken from that object. Otherwise, $text will be parsed to extract meta-data.

ObjectMethod insert ($type,$key,$val) -> $boolean

Adds a key-value pair of the given type to the object. Type is Set or Local. Callback used for the Prefs::Parser object, or can be used to add arbitrary new entries to a prefs cache.

Note that attempts to redefine final preferences will be ignored.

Returns 1 if the preference was defined, 0 otherwise.

ObjectMethod stringify ($html,\%shown) -> $text

Generate an (HTML if $html) representation of the content of this cache.