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312 lines
11 KiB
JavaScript
Executable file
312 lines
11 KiB
JavaScript
Executable file
// translation of https://github.com/djspiewak/cccp/blob/master/agent/src/main/scala/com/codecommit/cccp/agent/state.scala
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if (typeof ot === 'undefined') {
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var ot = {};
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}
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ot.Client = (function (global) {
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'use strict';
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// Client constructor
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function Client (revision) {
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this.revision = revision; // the next expected revision number
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this.setState(synchronized_); // start state
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}
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Client.prototype.setState = function (state) {
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this.state = state;
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};
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// Call this method when the user changes the document.
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Client.prototype.applyClient = function (operation) {
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this.setState(this.state.applyClient(this, operation));
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};
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// Call this method with a new operation from the server
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Client.prototype.applyServer = function (revision, operation) {
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this.setState(this.state.applyServer(this, revision, operation));
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};
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Client.prototype.applyOperations = function (head, operations) {
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this.setState(this.state.applyOperations(this, head, operations));
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};
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Client.prototype.serverAck = function (revision) {
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this.setState(this.state.serverAck(this, revision));
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};
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Client.prototype.serverReconnect = function () {
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if (typeof this.state.resend === 'function') { this.state.resend(this); }
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};
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// Transforms a selection from the latest known server state to the current
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// client state. For example, if we get from the server the information that
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// another user's cursor is at position 3, but the server hasn't yet received
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// our newest operation, an insertion of 5 characters at the beginning of the
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// document, the correct position of the other user's cursor in our current
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// document is 8.
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Client.prototype.transformSelection = function (selection) {
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return this.state.transformSelection(selection);
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};
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// Override this method.
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Client.prototype.sendOperation = function (revision, operation) {
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throw new Error("sendOperation must be defined in child class");
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};
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// Override this method.
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Client.prototype.applyOperation = function (operation) {
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throw new Error("applyOperation must be defined in child class");
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};
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// In the 'Synchronized' state, there is no pending operation that the client
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// has sent to the server.
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function Synchronized () {}
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Client.Synchronized = Synchronized;
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Synchronized.prototype.applyClient = function (client, operation) {
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// When the user makes an edit, send the operation to the server and
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// switch to the 'AwaitingConfirm' state
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client.sendOperation(client.revision, operation);
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return new AwaitingConfirm(operation);
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};
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Synchronized.prototype.applyServer = function (client, revision, operation) {
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if (revision - client.revision > 1) {
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throw new Error("Invalid revision.");
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}
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client.revision = revision;
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// When we receive a new operation from the server, the operation can be
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// simply applied to the current document
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client.applyOperation(operation);
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return this;
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};
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Synchronized.prototype.serverAck = function (client, revision) {
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throw new Error("There is no pending operation.");
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};
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// Nothing to do because the latest server state and client state are the same.
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Synchronized.prototype.transformSelection = function (x) { return x; };
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// Singleton
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var synchronized_ = new Synchronized();
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// In the 'AwaitingConfirm' state, there's one operation the client has sent
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// to the server and is still waiting for an acknowledgement.
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function AwaitingConfirm (outstanding) {
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// Save the pending operation
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this.outstanding = outstanding;
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}
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Client.AwaitingConfirm = AwaitingConfirm;
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AwaitingConfirm.prototype.applyClient = function (client, operation) {
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// When the user makes an edit, don't send the operation immediately,
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// instead switch to 'AwaitingWithBuffer' state
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return new AwaitingWithBuffer(this.outstanding, operation);
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};
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AwaitingConfirm.prototype.applyServer = function (client, revision, operation) {
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if (revision - client.revision > 1) {
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throw new Error("Invalid revision.");
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}
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client.revision = revision;
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// This is another client's operation. Visualization:
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//
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// /\
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// this.outstanding / \ operation
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// / \
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// \ /
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// pair[1] \ / pair[0] (new outstanding)
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// (can be applied \/
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// to the client's
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// current document)
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var pair = operation.constructor.transform(this.outstanding, operation);
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client.applyOperation(pair[1]);
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return new AwaitingConfirm(pair[0]);
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};
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AwaitingConfirm.prototype.serverAck = function (client, revision) {
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if (revision - client.revision > 1) {
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return new Stale(this.outstanding, client, revision).getOperations();
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}
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client.revision = revision;
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// The client's operation has been acknowledged
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// => switch to synchronized state
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return synchronized_;
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};
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AwaitingConfirm.prototype.transformSelection = function (selection) {
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return selection.transform(this.outstanding);
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};
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AwaitingConfirm.prototype.resend = function (client) {
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// The confirm didn't come because the client was disconnected.
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// Now that it has reconnected, we resend the outstanding operation.
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client.sendOperation(client.revision, this.outstanding);
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};
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// In the 'AwaitingWithBuffer' state, the client is waiting for an operation
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// to be acknowledged by the server while buffering the edits the user makes
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function AwaitingWithBuffer (outstanding, buffer) {
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// Save the pending operation and the user's edits since then
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this.outstanding = outstanding;
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this.buffer = buffer;
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}
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Client.AwaitingWithBuffer = AwaitingWithBuffer;
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AwaitingWithBuffer.prototype.applyClient = function (client, operation) {
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// Compose the user's changes onto the buffer
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var newBuffer = this.buffer.compose(operation);
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return new AwaitingWithBuffer(this.outstanding, newBuffer);
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};
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AwaitingWithBuffer.prototype.applyServer = function (client, revision, operation) {
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if (revision - client.revision > 1) {
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throw new Error("Invalid revision.");
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}
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client.revision = revision;
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// Operation comes from another client
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//
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// /\
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// this.outstanding / \ operation
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// / \
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// /\ /
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// this.buffer / \* / pair1[0] (new outstanding)
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// / \/
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// \ /
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// pair2[1] \ / pair2[0] (new buffer)
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// the transformed \/
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// operation -- can
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// be applied to the
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// client's current
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// document
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//
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// * pair1[1]
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var transform = operation.constructor.transform;
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var pair1 = transform(this.outstanding, operation);
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var pair2 = transform(this.buffer, pair1[1]);
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client.applyOperation(pair2[1]);
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return new AwaitingWithBuffer(pair1[0], pair2[0]);
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};
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AwaitingWithBuffer.prototype.serverAck = function (client, revision) {
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if (revision - client.revision > 1) {
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return new StaleWithBuffer(this.outstanding, this.buffer, client, revision).getOperations();
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}
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client.revision = revision;
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// The pending operation has been acknowledged
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// => send buffer
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client.sendOperation(client.revision, this.buffer);
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return new AwaitingConfirm(this.buffer);
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};
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AwaitingWithBuffer.prototype.transformSelection = function (selection) {
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return selection.transform(this.outstanding).transform(this.buffer);
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};
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AwaitingWithBuffer.prototype.resend = function (client) {
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// The confirm didn't come because the client was disconnected.
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// Now that it has reconnected, we resend the outstanding operation.
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client.sendOperation(client.revision, this.outstanding);
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};
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function Stale(acknowlaged, client, revision) {
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this.acknowlaged = acknowlaged;
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this.client = client;
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this.revision = revision;
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}
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Client.Stale = Stale;
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Stale.prototype.applyClient = function (client, operation) {
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return new StaleWithBuffer(this.acknowlaged, operation, client, this.revision);
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};
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Stale.prototype.applyServer = function (client, revision, operation) {
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throw new Error("Ignored server-side change.");
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};
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Stale.prototype.applyOperations = function (client, head, operations) {
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var transform = this.acknowlaged.constructor.transform;
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for (var i = 0; i < operations.length; i++) {
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var op = ot.TextOperation.fromJSON(operations[i]);
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var pair = transform(this.acknowlaged, op);
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client.applyOperation(pair[1]);
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this.acknowlaged = pair[0];
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}
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client.revision = this.revision;
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return synchronized_;
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};
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Stale.prototype.serverAck = function (client, revision) {
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throw new Error("There is no pending operation.");
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};
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Stale.prototype.transformSelection = function (selection) {
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return selection;
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};
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Stale.prototype.getOperations = function () {
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this.client.getOperations(this.client.revision, this.revision - 1); // acknowlaged is the one at revision
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return this;
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};
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function StaleWithBuffer(acknowlaged, buffer, client, revision) {
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this.acknowlaged = acknowlaged;
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this.buffer = buffer;
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this.client = client;
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this.revision = revision;
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}
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Client.StaleWithBuffer = StaleWithBuffer;
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StaleWithBuffer.prototype.applyClient = function (client, operation) {
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var buffer = this.buffer.compose(operation);
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return new StaleWithBuffer(this.acknowlaged, buffer, client, this.revision);
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};
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StaleWithBuffer.prototype.applyServer = function (client, revision, operation) {
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throw new Error("Ignored server-side change.");
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};
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StaleWithBuffer.prototype.applyOperations = function (client, head, operations) {
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var transform = this.acknowlaged.constructor.transform;
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for (var i = 0; i < operations.length; i++) {
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var op = ot.TextOperation.fromJSON(operations[i]);
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var pair1 = transform(this.acknowlaged, op);
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var pair2 = transform(this.buffer, pair1[1]);
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client.applyOperation(pair2[1]);
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this.acknowlaged = pair1[0];
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this.buffer = pair2[0];
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}
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client.revision = this.revision;
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client.sendOperation(client.revision, this.buffer);
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return new AwaitingConfirm(this.buffer);
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};
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StaleWithBuffer.prototype.serverAck = function (client, revision) {
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throw new Error("There is no pending operation.");
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};
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StaleWithBuffer.prototype.transformSelection = function (selection) {
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return selection;
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};
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StaleWithBuffer.prototype.getOperations = function () {
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this.client.getOperations(this.client.revision, this.revision - 1); // acknowlaged is the one at revision
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return this;
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};
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return Client;
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}(this));
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if (typeof module === 'object') {
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module.exports = ot.Client;
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}
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