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/*******************************************************************************
* Copyright (c) 2015 itemis AG (http://www.itemis.eu) and others.
* This program and the accompanying materials are made available under the
* terms of the Eclipse Public License 2.0 which is available at
* http://www.eclipse.org/legal/epl-2.0.
*
* SPDX-License-Identifier: EPL-2.0
*******************************************************************************/
define(['xtext/services/XtextService', 'jquery'], function(XtextService, jQuery) {
/**
* Service class for updating the server-side representation of a resource.
* This service only makes sense with a stateful server, where an update request is sent
* after each modification. This can greatly improve response times compared to the
* stateless alternative, where the full text content is sent with each service request.
*/
function UpdateService(serviceUrl, resourceId) {
this.initialize(serviceUrl, 'update', resourceId, this);
this._completionCallbacks = [];
};
UpdateService.prototype = new XtextService();
/**
* Compute a delta between two versions of a text. If a difference is found, the result
* contains three properties:
* deltaText - the text to insert into s1
* deltaOffset - the text insertion offset
* deltaReplaceLength - the number of characters that shall be replaced by the inserted text
*/
UpdateService.prototype.computeDelta = function(s1, s2, result) {
var start = 0, s1length = s1.length, s2length = s2.length;
while (start < s1length && start < s2length && s1.charCodeAt(start) === s2.charCodeAt(start)) {
start++;
}
if (start === s1length && start === s2length) {
return;
}
result.deltaOffset = start;
if (start === s1length) {
result.deltaText = s2.substring(start, s2length);
result.deltaReplaceLength = 0;
return;
} else if (start === s2length) {
result.deltaText = '';
result.deltaReplaceLength = s1length - start;
return;
}
var end1 = s1length - 1, end2 = s2length - 1;
while (end1 >= start && end2 >= start && s1.charCodeAt(end1) === s2.charCodeAt(end2)) {
end1--;
end2--;
}
result.deltaText = s2.substring(start, end2 + 1);
result.deltaReplaceLength = end1 - start + 1;
};
/**
* Invoke all completion callbacks and clear the list afterwards.
*/
UpdateService.prototype.onComplete = function(xhr, textStatus) {
var callbacks = this._completionCallbacks;
this._completionCallbacks = [];
for (var i = 0; i < callbacks.length; i++) {
var callback = callbacks[i].callback;
var params = callbacks[i].params;
callback(params);
}
}
/**
* Add a callback to be invoked when the service call has completed.
*/
UpdateService.prototype.addCompletionCallback = function(callback, params) {
this._completionCallbacks.push({callback: callback, params: params});
}
UpdateService.prototype.invoke = function(editorContext, params, deferred) {
if (deferred === undefined) {
deferred = jQuery.Deferred();
}
var knownServerState = editorContext.getServerState();
if (knownServerState.updateInProgress) {
var self = this;
this.addCompletionCallback(function() { self.invoke(editorContext, params, deferred) });
return deferred.promise();
}
var serverData = {
contentType: params.contentType
};
var currentText = editorContext.getText();
if (params.sendFullText || knownServerState.text === undefined) {
serverData.fullText = currentText;
} else {
this.computeDelta(knownServerState.text, currentText, serverData);
if (serverData.deltaText === undefined) {
if (params.forceUpdate) {
serverData.deltaText = '';
serverData.deltaOffset = editorContext.getCaretOffset();
serverData.deltaReplaceLength = 0;
} else {
deferred.resolve(knownServerState);
this.onComplete();
return deferred.promise();
}
}
serverData.requiredStateId = knownServerState.stateId;
}
knownServerState.updateInProgress = true;
var self = this;
self.sendRequest(editorContext, {
type: 'PUT',
data: serverData,
success: function(result) {
if (result.conflict) {
// The server has lost its session state and the resource is loaded from the server
if (knownServerState.text !== undefined) {
delete knownServerState.updateInProgress;
delete knownServerState.text;
delete knownServerState.stateId;
self.invoke(editorContext, params, deferred);
} else {
deferred.reject(result.conflict);
}
return false;
}
var listeners = editorContext.updateServerState(currentText, result.stateId);
for (var i = 0; i < listeners.length; i++) {
self.addCompletionCallback(listeners[i], params);
}
deferred.resolve(result);
},
error: function(xhr, textStatus, errorThrown) {
if (xhr.status == 404 && !params.loadFromServer && knownServerState.text !== undefined) {
// The server has lost its session state and the resource is not loaded from the server
delete knownServerState.updateInProgress;
delete knownServerState.text;
delete knownServerState.stateId;
self.invoke(editorContext, params, deferred);
return true;
}
deferred.reject(errorThrown);
},
complete: self.onComplete.bind(self)
}, true);
return deferred.promise().always(function() {
knownServerState.updateInProgress = false;
});
};
return UpdateService;
});
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