Pipeline Class

Module: cc

A pipeline describes a sequence of manipulations, each manipulation is called a pipe.
It's designed for loading process. so items should be urls, and the url will be the identity of each item during the process.
A list of items can flow in the pipeline and it will output the results of all pipes.
They flow in the pipeline like water in tubes, they go through pipe by pipe separately.
Finally all items will flow out the pipeline and the process is finished.

Index

Methods

• constructor Constructor, pass an array of pipes to construct a new Pipeline,...
• insertPipe Insert a new pipe at the given index of the pipeline.
• insertPipeAfter Insert a pipe to the end of an existing pipe.
• appendPipe Add a new pipe at the end of the pipeline.
• flowIn Let new items flow into the pipeline.
• copyItemStates Copy the item states from one source item to all destination items.
• getItem Returns an item in pipeline.
• removeItem Removes an completed item in pipeline.
• clear Clear the current pipeline, this function will clean up the items.

Details

Methods

constructor

Constructor, pass an array of pipes to construct a new Pipeline, the pipes will be chained in the given order.
A pipe is an object which must contain an id in string and a handle function, the id must be unique in the pipeline.
It can also include async property to identify whether it's an asynchronous process.

Parameters

• pipes Array

Examples

var pipeline = new Pipeline([
     {
         id: 'Downloader',
         handle: function (item, callback) {},
         async: true
     },
     {id: 'Parser', handle: function (item) {}, async: false}
 ]);

insertPipe

Insert a new pipe at the given index of the pipeline.
A pipe must contain an id in string and a handle function, the id must be unique in the pipeline.

Parameters

• pipe Object The pipe to be inserted
• index Number The index to insert

insertPipeAfter

Insert a pipe to the end of an existing pipe. The existing pipe must be a valid pipe in the pipeline.

Parameters

• refPipe Object An existing pipe in the pipeline.
• newPipe Object The pipe to be inserted.

appendPipe

Add a new pipe at the end of the pipeline.
A pipe must contain an id in string and a handle function, the id must be unique in the pipeline.

Parameters

• pipe Object The pipe to be appended

flowIn

Let new items flow into the pipeline.
Each item can be a simple url string or an object, if it's an object, it must contain id property.
You can specify its type by type property, by default, the type is the extension name in url.
By adding a skips property including pipe ids, you can skip these pipe.
The object can contain any supplementary property as you want.

Parameters

• items Array

Examples

pipeline.flowIn([
     'res/Background.png',
     {
         id: 'res/scene.json',
         type: 'scene',
         name: 'scene',
         skips: ['Downloader']
     }
 ]);

copyItemStates

Copy the item states from one source item to all destination items.
It's quite useful when a pipe generate new items from one source item,
then you should flowIn these generated items into pipeline,
but you probably want them to skip all pipes the source item already go through,
you can achieve it with this API.

For example, an unzip pipe will generate more items, but you won't want them to pass unzip or download pipe again.

Parameters

• srcItem Object The source item
• dstItems Array | Object A single destination item or an array of destination items

getItem

Returns an item in pipeline.

Parameters

• id Object The id of the item

removeItem

Removes an completed item in pipeline. It will only remove the cache in the pipeline or loader, its dependencies won't be released. cc.loader provided another method to completely cleanup the resource and its dependencies, please refer to cc.loader.release

Parameters

• id Object The id of the item

clear

Clear the current pipeline, this function will clean up the items.