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Updating terminology in function names and comments so that operation…
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…s are streams of changes, not streams of (levenshtein distance) operations which was confusing
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@fitzgen
fitzgen committed Apr 5, 2011
1 parent 35643e5 commit 051354c
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Showing 6 changed files with 109 additions and 107 deletions.
22 changes: 11 additions & 11 deletions apply.js
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Original file line number Diff line number Diff line change
Expand Up @@ -9,34 +9,34 @@
/*global define */

define(["./operations"], function (operations) {
return function (ops, doc) {
return function (op, doc) {
var i,
len,
index = 0,
newDoc = "";
for ( i = 0, len = ops.length; i < len; i += 1 ) {
switch ( operations.type(ops[i]) ) {
for ( i = 0, len = op.length; i < len; i += 1 ) {
switch ( operations.type(op[i]) ) {
case "retain":
newDoc += doc.slice(0, operations.val(ops[i]));
doc = doc.slice(operations.val(ops[i]));
newDoc += doc.slice(0, operations.val(op[i]));
doc = doc.slice(operations.val(op[i]));
break;
case "insert":
newDoc += operations.val(ops[i]);
newDoc += operations.val(op[i]);
break;
case "delete":
if ( doc.indexOf(operations.val(ops[i])) !== 0 ) {
throw new TypeError("Expected '" + operations.val(ops[i])
if ( doc.indexOf(operations.val(op[i])) !== 0 ) {
throw new TypeError("Expected '" + operations.val(op[i])
+ "' to delete, found '" + doc.slice(0, 10)
+ "...'");
} else {
doc = doc.slice(operations.val(ops[i]).length);
doc = doc.slice(operations.val(op[i]).length);
break;
}
default:
throw new TypeError("Unknown operation: "
+ operations.type(ops[i]));
+ operations.type(op[i]));
}
}
return newDoc;
}
};
});
12 changes: 6 additions & 6 deletions client.js
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Original file line number Diff line number Diff line change
Expand Up @@ -27,8 +27,8 @@ define([
var i, len, msg;
for ( i = 0, len = outgoing.length; i < len; i++ ) {
msg = outgoing[i];
xform(messages.operations(msg), ops, function (aPrime, bPrime) {
messages.operations(msg, aPrime);
xform(messages.operation(msg), ops, function (aPrime, bPrime) {
messages.operation(msg, aPrime);
messages.document(msg, apply(messages.document(msg), aPrime));
messages.revision(msg, messages.revision(msg)+1);
ops = bPrime;
Expand Down Expand Up @@ -62,7 +62,7 @@ define([
uiDoc = ui.getDocument();
if ( uiDoc !== previousDoc ) {
msg = {};
messages.operations(msg, operations.getOperations(previousDoc, uiDoc));
messages.operation(msg, operations.operation(previousDoc, uiDoc));
messages.document(msg, uiDoc);
messages.revision(msg, ++previousRevision);
messages.id(msg, id);
Expand All @@ -87,8 +87,8 @@ define([
// to have to do a deep equality test on every check here.
function isOurOutgoing (msg, outgoing) {
var top = outgoing[0],
topOps = messages.operations(top),
msgOps = messages.operations(msg),
topOps = messages.operation(top),
msgOps = messages.operation(msg),
i = 0,
len = msgOps.length;
if ( messages.id(msg) !== messages.id(top) ) {
Expand Down Expand Up @@ -144,7 +144,7 @@ define([
outgoing.shift();
} else {
// TODO: need to handle cursor selection and index
xformEach(outgoing, messages.operations(msg));
xformEach(outgoing, messages.operation(msg));

// TODO: cursor position
if ( outgoing.length ) {
Expand Down
2 changes: 1 addition & 1 deletion messages.js
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Original file line number Diff line number Diff line change
Expand Up @@ -25,7 +25,7 @@ define(function () {
// client connect.
document: defineGetSet("doc"),
revision: defineGetSet("rev"),
operations: defineGetSet("ops"),
operation: defineGetSet("op"),
id: defineGetSet("id")
};

Expand Down
76 changes: 39 additions & 37 deletions operations.js
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Original file line number Diff line number Diff line change
@@ -1,6 +1,6 @@
// This module defines the implementation of our operations. How they are
// represented, their construction, and how to calculate the set of operations
// to change some document A in to document B.
// Operations are a stream of individual changes which span the whole document
// from start to finish. Changes have a type which is one of retain, insert, or
// delete, and have associated data based on their type.


/*jslint onevar: true, undef: true, eqeqeq: true, bitwise: true,
Expand All @@ -11,7 +11,7 @@

define(function () {

// Simple operation constructors.
// Simple change constructors.

function insert (chars) {
return ["insert", chars];
Expand All @@ -25,12 +25,12 @@ define(function () {
return ["retain", n];
}

function type (operation) {
return operation[0];
function type (change) {
return change[0];
}

function val (operation) {
return operation[1];
function val (change) {
return change[1];
}

// We don't want to copy arrays all the time, aren't mutating lists, and
Expand Down Expand Up @@ -69,20 +69,20 @@ define(function () {
// Abstract out the table in case I want to change the implementation to
// arrays of arrays or something.

function put (table, x, y, ops) {
return (table[String(x) + "," + String(y)] = ops);
function put (table, x, y, changes) {
return (table[String(x) + "," + String(y)] = changes);
}

function get (table, x, y) {
var ops = table[String(x) + "," + String(y)];
if ( ops ) {
return ops;
var changes = table[String(x) + "," + String(y)];
if ( changes ) {
return changes;
} else {
throw new TypeError("No operations at " + String(x) + "," + String(y));
}
}

function makeOperationsTable (s, t) {
function makeChangesTable (s, t) {
var table = {},
n = s.length,
m = t.length,
Expand All @@ -101,50 +101,52 @@ define(function () {
}

function chooseCell (table, x, y, k) {
var prevOps = get(table, x, y-1),
min = prevOps.length,
var prevChanges = get(table, x, y-1),
min = prevChanges.length,
direction = "up";

if ( get(table, x-1, y).length < min ) {
prevOps = get(table, x-1, y);
min = prevOps.length;
prevChanges = get(table, x-1, y);
min = prevChanges.length;
direction = "left";
}

if ( get(table, x-1, y-1).length < min ) {
prevOps = get(table, x-1, y-1);
min = prevOps.length;
prevChanges = get(table, x-1, y-1);
min = prevChanges.length;
direction = "diagonal";
}

return k(direction, prevOps);
return k(direction, prevChanges);
}

return {

getOperations: function (s, t) {
// Constructor for operations (which are a stream of changes). Uses
// variation of Levenshtein Distance.
operation: function (s, t) {
var n = s.length,
m = t.length,
i,
j,
ops = makeOperationsTable(s, t);
changes = makeChangesTable(s, t);
for ( i = 1; i <= m; i += 1 ) {
for ( j = 1; j <= n; j += 1 ) {
chooseCell(ops, i, j, function (direction, prevOps) {
chooseCell(changes, i, j, function (direction, prevChanges) {
switch ( direction ) {
case "left":
put(ops, i, j, cons(insert(t.charAt(i-1)), prevOps));
put(changes, i, j, cons(insert(t.charAt(i-1)), prevChanges));
break;
case "up":
put(ops, i, j, cons(del(s.charAt(j-1)), prevOps));
put(changes, i, j, cons(del(s.charAt(j-1)), prevChanges));
break;
case "diagonal":
if ( s.charAt(j-1) === t.charAt(i-1) ) {
put(ops, i, j, cons(retain(1), prevOps));
put(changes, i, j, cons(retain(1), prevChanges));
} else {
put(ops, i, j, cons(insert(t.charAt(i-1)),
cons(del(s.charAt(j-1)),
prevOps)));
put(changes, i, j, cons(insert(t.charAt(i-1)),
cons(del(s.charAt(j-1)),
prevChanges)));
}
break;
default:
Expand All @@ -153,7 +155,7 @@ define(function () {
});
}
}
return get(ops, i-1, j-1).toArray().reverse();
return get(changes, i-1, j-1).toArray().reverse();
},

insert: insert,
Expand All @@ -162,16 +164,16 @@ define(function () {
type: type,
val: val,

isDelete: function (op) {
return typeof op === "object" && type(op) === "delete";
isDelete: function (change) {
return typeof change === "object" && type(change) === "delete";
},

isRetain: function (op) {
return typeof op === "object" && type(op) === "retain";
isRetain: function (change) {
return typeof change === "object" && type(change) === "retain";
},

isInsert: function (op) {
return typeof op === "object" && type(op) === "insert";
isInsert: function (change) {
return typeof change === "object" && type(change) === "insert";
}

};
Expand Down
8 changes: 4 additions & 4 deletions ot.js
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Original file line number Diff line number Diff line change
Expand Up @@ -43,10 +43,10 @@ define([
}.bind(this));
};

manager.applyOperations = function (message) {
manager.applyOperation = function (message) {
var id = messages.id(message),
newRev = messages.revision(message),
ops = messages.operations(message),
op = messages.operation(message),
emit = this.emit.bind(this);

store.getDocument(id, function (err, doc) {
Expand All @@ -55,7 +55,7 @@ define([
} else {
if ( newRev === doc.rev+1 ) {
try {
doc.doc = apply(ops, doc.doc);
doc.doc = apply(op, doc.doc);
} catch (e) {
emit("error", e);
return;
Expand All @@ -74,7 +74,7 @@ define([
msg = {};
messages.revision(msg, doc.rev);
messages.id(msg, doc.id);
messages.operations(msg, ops);
messages.operation(msg, op);
messages.document(msg, doc.doc);
emit("update", msg);
}
Expand Down
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