ttrss/lib/dojo/data/util/simpleFetch.js

100 lines
4.0 KiB
JavaScript

/*
Copyright (c) 2004-2011, The Dojo Foundation All Rights Reserved.
Available via Academic Free License >= 2.1 OR the modified BSD license.
see: http://dojotoolkit.org/license for details
*/
if(!dojo._hasResource["dojo.data.util.simpleFetch"]){ //_hasResource checks added by build. Do not use _hasResource directly in your code.
dojo._hasResource["dojo.data.util.simpleFetch"] = true;
dojo.provide("dojo.data.util.simpleFetch");
dojo.require("dojo.data.util.sorter");
dojo.getObject("data.util.simpleFetch", true, dojo);
dojo.data.util.simpleFetch.fetch = function(/* Object? */ request){
// summary:
// The simpleFetch mixin is designed to serve as a set of function(s) that can
// be mixed into other datastore implementations to accelerate their development.
// The simpleFetch mixin should work well for any datastore that can respond to a _fetchItems()
// call by returning an array of all the found items that matched the query. The simpleFetch mixin
// is not designed to work for datastores that respond to a fetch() call by incrementally
// loading items, or sequentially loading partial batches of the result
// set. For datastores that mixin simpleFetch, simpleFetch
// implements a fetch method that automatically handles eight of the fetch()
// arguments -- onBegin, onItem, onComplete, onError, start, count, sort and scope
// The class mixing in simpleFetch should not implement fetch(),
// but should instead implement a _fetchItems() method. The _fetchItems()
// method takes three arguments, the keywordArgs object that was passed
// to fetch(), a callback function to be called when the result array is
// available, and an error callback to be called if something goes wrong.
// The _fetchItems() method should ignore any keywordArgs parameters for
// start, count, onBegin, onItem, onComplete, onError, sort, and scope.
// The _fetchItems() method needs to correctly handle any other keywordArgs
// parameters, including the query parameter and any optional parameters
// (such as includeChildren). The _fetchItems() method should create an array of
// result items and pass it to the fetchHandler along with the original request object
// -- or, the _fetchItems() method may, if it wants to, create an new request object
// with other specifics about the request that are specific to the datastore and pass
// that as the request object to the handler.
//
// For more information on this specific function, see dojo.data.api.Read.fetch()
request = request || {};
if(!request.store){
request.store = this;
}
var self = this;
var _errorHandler = function(errorData, requestObject){
if(requestObject.onError){
var scope = requestObject.scope || dojo.global;
requestObject.onError.call(scope, errorData, requestObject);
}
};
var _fetchHandler = function(items, requestObject){
var oldAbortFunction = requestObject.abort || null;
var aborted = false;
var startIndex = requestObject.start?requestObject.start:0;
var endIndex = (requestObject.count && (requestObject.count !== Infinity))?(startIndex + requestObject.count):items.length;
requestObject.abort = function(){
aborted = true;
if(oldAbortFunction){
oldAbortFunction.call(requestObject);
}
};
var scope = requestObject.scope || dojo.global;
if(!requestObject.store){
requestObject.store = self;
}
if(requestObject.onBegin){
requestObject.onBegin.call(scope, items.length, requestObject);
}
if(requestObject.sort){
items.sort(dojo.data.util.sorter.createSortFunction(requestObject.sort, self));
}
if(requestObject.onItem){
for(var i = startIndex; (i < items.length) && (i < endIndex); ++i){
var item = items[i];
if(!aborted){
requestObject.onItem.call(scope, item, requestObject);
}
}
}
if(requestObject.onComplete && !aborted){
var subset = null;
if(!requestObject.onItem){
subset = items.slice(startIndex, endIndex);
}
requestObject.onComplete.call(scope, subset, requestObject);
}
};
this._fetchItems(request, _fetchHandler, _errorHandler);
return request; // Object
};
}