datatables.ajax.pipelining.js Maven / Gradle / Ivy

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There is a newer version: 1.1.0
var oCache = {
	iCacheLower : -1
};

function fnSetKey(aoData, sKey, mValue) {
	for ( var i = 0, iLen = aoData.length; i < iLen; i++) {
		if (aoData[i].name == sKey) {
			aoData[i].value = mValue;
		}
	}
}

function fnGetKey(aoData, sKey) {
	for ( var i = 0, iLen = aoData.length; i < iLen; i++) {
		if (aoData[i].name == sKey) {
			return aoData[i].value;
		}
	}
	return null;
}

function fnDataTablesPipeline(sSource, aoData, fnCallback) {
	var iPipe = 5; /* Ajust the pipe size */

	var bNeedServer = false;
	var sEcho = fnGetKey(aoData, "sEcho");
	var iRequestStart = fnGetKey(aoData, "iDisplayStart");
	var iRequestLength = fnGetKey(aoData, "iDisplayLength");
	var iRequestEnd = iRequestStart + iRequestLength;
	oCache.iDisplayStart = iRequestStart;

	/* outside pipeline? */
	if (oCache.iCacheLower < 0 || iRequestStart < oCache.iCacheLower
			|| iRequestEnd > oCache.iCacheUpper) {
		bNeedServer = true;
	}

	/* sorting etc changed? */
	if (oCache.lastRequest && !bNeedServer) {
		for ( var i = 0, iLen = aoData.length; i < iLen; i++) {
			if (aoData[i].name != "iDisplayStart"
					&& aoData[i].name != "iDisplayLength"
					&& aoData[i].name != "sEcho") {
				if (aoData[i].value != oCache.lastRequest[i].value) {
					bNeedServer = true;
					break;
				}
			}
		}
	}

	/* Store the request for checking next time around */
	oCache.lastRequest = aoData.slice();

	if (bNeedServer) {
		if (iRequestStart < oCache.iCacheLower) {
			iRequestStart = iRequestStart - (iRequestLength * (iPipe - 1));
			if (iRequestStart < 0) {
				iRequestStart = 0;
			}
		}

		oCache.iCacheLower = iRequestStart;
		oCache.iCacheUpper = iRequestStart + (iRequestLength * iPipe);
		oCache.iDisplayLength = fnGetKey(aoData, "iDisplayLength");
		fnSetKey(aoData, "iDisplayStart", iRequestStart);
		fnSetKey(aoData, "iDisplayLength", iRequestLength * iPipe);

		$.getJSON(sSource, aoData, function(json) {
			/* Callback processing */
			oCache.lastJson = jQuery.extend(true, {}, json);

			if (oCache.iCacheLower != oCache.iDisplayStart) {
				json.aaData
						.splice(0, oCache.iDisplayStart - oCache.iCacheLower);
			}
			json.aaData.splice(oCache.iDisplayLength, json.aaData.length);

			fnCallback(json)
		});
	} else {
		json = jQuery.extend(true, {}, oCache.lastJson);
		json.sEcho = sEcho; /* Update the echo for each response */
		json.aaData.splice(0, iRequestStart - oCache.iCacheLower);
		json.aaData.splice(iRequestLength, json.aaData.length);
		fnCallback(json);
		return;
	}
}