MapperCache

For every view element or document fragment tracked by MapperCache, it holds currently cached data, or more precisely, model offset to view position mappings. See also MappingCache and CacheItem.

If an item is tracked by MapperCache it has an entry in this structure, so this structure can be used to check which items are tracked by MapperCache. When an item is no longer tracked, it is removed from this structure.

Although MappingCache and CacheItem structures allows for caching any model offsets and view positions, we only cache values for model offsets that are after a view node. So, in essence, positions inside text nodes are not cached. However, it takes from one to at most a few steps, to get from a cached position to a position that is inside a view text node.

Additionally, only one item per modelOffset is cached. There can be several view positions that map to the same modelOffset. Only the first save for modelOffset is stored.

Callback fired whenever there is a direct or indirect children change in tracked view element or tracked view document fragment.

This is specified as a property to make it easier to set as an event callback and to later turn off that event.

Callback fired whenever a view text node directly or indirectly inside a tracked view element or tracked view document fragment changes its text data.

This is specified as a property to make it easier to set as an event callback and to later turn off that event.

When MapperCache saves view position -> model offset mapping, a CacheItem is inserted into certain MappingCache#cacheList at some index. Additionally, we store that index with the view node that is before the cached view position.

This allows to quickly get a cache list item related to certain view node, and hence, for fast cache invalidation.

For example, consider view: <p>Some <strong>bold</strong> text.</p>, where <p> is a view element tracked by MapperCache. If all <p> children were visited by MapperCache, then <p> cache list would have four items, related to following model offsets: 0, 5, 9, 15. Then, view node "Some " would have index 1, <strong> index 2, and " text." index 3`.

Note that the index related with a node is always greater than 0. The first item in cache list is always for model offset 0 (and view offset 0), and it is not related to any node.

Delegates selected events to another Emitter. For instance:

emitterA.delegate( 'eventX' ).to( emitterB );
emitterA.delegate( 'eventX', 'eventY' ).to( emitterC );

then eventX is delegated (fired by) emitterB and emitterC along with data:

emitterA.fire( 'eventX', data );

and eventY is delegated (fired by) emitterC along with data:

emitterA.fire( 'eventY', data );

Parameters

events : Array<string>

Event names that will be delegated to another emitter.

Returns

EmitterMixinDelegateChain

Fires an event, executing all callbacks registered for it.

The first parameter passed to callbacks is an EventInfo object, followed by the optional args provided in the fire() method call.

Type parameters

TEvent : extends BaseEvent

The type describing the event. See BaseEvent.

Parameters

eventOrInfo : GetNameOrEventInfo<TEvent>

The name of the event or EventInfo object if event is delegated.

args : TEvent[ 'args' ]

Additional arguments to be passed to the callbacks.

Returns

GetEventInfo<TEvent>[ 'return' ]

By default the method returns undefined. However, the return value can be changed by listeners through modification of the evt.return's property (the event info is the first param of every callback).

For given modelOffset inside a model element mapped to given viewContainer, it returns the closest saved cache item (view position and related model offset) to the requested one.

It can be exactly the requested mapping, or it can be mapping that is the closest starting point to look for the requested mapping.

viewContainer must be a view element or document fragment that is mapped by the Mapper.

If viewContainer is not yet tracked by the MapperCache, it will be automatically tracked after calling this method.

Note: this method will automatically "hoist" cached positions, i.e. it will return a position that is closest to the tracked element.

For example, if <p> is tracked element, and ^ is cached position:

<p>This is <strong>some <em>heavily <u>formatted</u>^</em></strong> text.</p>

If this position would be returned, instead, a position directly in <p> would be returned:

<p>This is <strong>some <em>heavily <u>formatted</u></em></strong>^ text.</p>

Note, that modelOffset for both positions is the same.

Parameters

viewContainer : ViewElement | ViewDocumentFragment

Tracked view element or document fragment, which cache will be used.

modelOffset : number

Model offset in a model element or document fragment, which is mapped to viewContainer.

Returns

CacheItem

Registers a callback function to be executed when an event is fired in a specific (emitter) object.

Events can be grouped in namespaces using :. When namespaced event is fired, it additionally fires all callbacks for that namespace.

// myEmitter.on( ... ) is a shorthand for myEmitter.listenTo( myEmitter, ... ).
myEmitter.on( 'myGroup', genericCallback );
myEmitter.on( 'myGroup:myEvent', specificCallback );

// genericCallback is fired.
myEmitter.fire( 'myGroup' );
// both genericCallback and specificCallback are fired.
myEmitter.fire( 'myGroup:myEvent' );
// genericCallback is fired even though there are no callbacks for "foo".
myEmitter.fire( 'myGroup:foo' );

An event callback can stop the event and set the return value of the fire method.

Type parameters

TEvent : extends BaseEvent

The type describing the event. See BaseEvent.

Parameters

emitter : Emitter

The object that fires the event.

event : TEvent[ 'name' ]

The name of the event.

callback : GetCallback<TEvent>

The function to be called on event.

[ options ] : GetCallbackOptions<TEvent>

Additional options.

Returns

void

Stops executing the callback on the given event. Shorthand for this.stopListening( this, event, callback ).

Parameters

event : string

The name of the event.

callback : Function

The function to stop being called.

Returns

void

Registers a callback function to be executed when an event is fired.

Shorthand for this.listenTo( this, event, callback, options ) (it makes the emitter listen on itself).

Type parameters

TEvent : extends BaseEvent

The type descibing the event. See BaseEvent.

Parameters

event : TEvent[ 'name' ]

The name of the event.

callback : GetCallback<TEvent>

The function to be called on event.

[ options ] : GetCallbackOptions<TEvent>

Additional options.

Returns

void

Registers a callback function to be executed on the next time the event is fired only. This is similar to calling on followed by off in the callback.

Type parameters

TEvent : extends BaseEvent

The type descibing the event. See BaseEvent.

Parameters

event : TEvent[ 'name' ]

The name of the event.

callback : GetCallback<TEvent>

The function to be called on event.

[ options ] : GetCallbackOptions<TEvent>

Additional options.

Returns

void

Saves cache for given view position mapping <-> model offset mapping. The view position should be after a node (i.e. it cannot be the first position inside its parent, or in other words, viewOffset must be greater than 0).

Note, that if modelOffset for given viewContainer was already saved, the stored view position (i.e. parent+offset) will not be overwritten. However, it is important to still save it, as we still store additional data related to cached view positions.

Parameters

viewParent : ViewElement | ViewDocumentFragment

View position parent.

viewOffset : number

View position offset. Must be greater than 0.

viewContainer : ViewElement | ViewDocumentFragment

Tracked view position ascendant (it may be the direct parent of the view position).

modelOffset : number

Model offset in the model element or document fragment which is mapped to viewContainer.

Returns

void

Starts tracking given viewContainer, which must be mapped to a model element or model document fragment.

Note, that this method is automatically called by MapperCache#getClosest() and there is no need to call it manually.

This method initializes the cache for viewContainer and adds callbacks for change event fired by viewContainer. MapperCache listens to change event on the tracked elements to invalidate the stored cache.

Parameters

viewContainer : ViewElement | ViewDocumentFragment

Returns

CacheItem

Stops delegating events. It can be used at different levels:

• To stop delegating all events.
• To stop delegating a specific event to all emitters.
• To stop delegating a specific event to a specific emitter.

Parameters

[ event ] : string

The name of the event to stop delegating. If omitted, stops it all delegations.

[ emitter ] : Emitter

(requires event) The object to stop delegating a particular event to. If omitted, stops delegation of event to all emitters.

Returns

void

Stops listening for events. It can be used at different levels:

• To stop listening to a specific callback.
• To stop listening to a specific event.
• To stop listening to all events fired by a specific object.
• To stop listening to all events fired by all objects.

Parameters

[ emitter ] : Emitter

The object to stop listening to. If omitted, stops it for all objects.

[ event ] : string

(Requires the emitter) The name of the event to stop listening to. If omitted, stops it for all events from emitter.

[ callback ] : Function

(Requires the event) The function to be removed from the call list for the given event.

Returns

void

Stops tracking given viewContainer.

It removes the cached data and stops listening to change event on the viewContainer.

Parameters

viewContainer : ViewElement | ViewDocumentFragment

Returns

void

Clears all the stored cache that is after given viewNode. The viewNode can be any node that is inside a tracked view element or view document fragment.

In reality, this function may clear a bit more cache than just "starting after" viewNode, but it is guaranteed that at least all cache after viewNode is invalidated.

Parameters

viewNode : ViewNode

Returns

void

Clears all the cache for given tracked viewContainer.

Parameters

viewContainer : ViewElement | ViewDocumentFragment

Returns

void

Clears all the cache in the cache list related to given viewContainer, starting from index (inclusive).

Parameters

viewContainer : ViewElement | ViewDocumentFragment

index : number

Returns

void

Invalidates cache inside viewParent, starting from given index in that parent.

This method may clear a bit more cache than just what was saved after given index, but it is guaranteed that at least it will invalidate everything after index.

Parameters

viewParent : ViewElement | ViewDocumentFragment

index : number

Returns

void

Finds a cache item in the given cache list, which modelOffset is closest (but smaller or equal) to given offset.

Since cacheList is a sorted array, this uses binary search to retrieve the item quickly.

Parameters

cacheList : Array<CacheItem>

offset : number

Returns

CacheItem