diff options
Diffstat (limited to 'src/node/handler')
| -rw-r--r-- | src/node/handler/PadMessageHandler.js | 41 |
1 files changed, 29 insertions, 12 deletions
diff --git a/src/node/handler/PadMessageHandler.js b/src/node/handler/PadMessageHandler.js index 8a5a92bb..f60d91da 100644 --- a/src/node/handler/PadMessageHandler.js +++ b/src/node/handler/PadMessageHandler.js @@ -436,15 +436,22 @@ function handleUserInfoUpdate(client, message) } /** - * Handles a USERINFO_UPDATE, that means that a user have changed his color or name. Anyway, we get both informations - * This Method is nearly 90% copied out of the Etherpad Source Code. So I can't tell you what happens here exactly - * Look at https://github.com/ether/pad/blob/master/etherpad/src/etherpad/collab/collab_server.js in the function applyUserChanges() + * Handles a USER_CHANGES message, where the client submits its local + * edits as a changeset. + * + * This handler's job is to update the incoming changeset so that it applies + * to the latest revision, then add it to the pad, broadcast the changes + * to all other clients, and send a confirmation to the submitting client. + * + * This function is based on a similar one in the original Etherpad. + * See https://github.com/ether/pad/blob/master/etherpad/src/etherpad/collab/collab_server.js in the function applyUserChanges() + * * @param client the client that send this message * @param message the message from the client */ function handleUserChanges(client, message) { - //check if all ok + // Make sure all required fields are present if(message.data.baseRev == null) { messageLogger.warn("Dropped message, USER_CHANGES Message has no baseRev!"); @@ -487,22 +494,23 @@ function handleUserChanges(client, message) { //ex. _checkChangesetAndPool - //Copied from Etherpad, don't know what it does exactly try { - //this looks like a changeset check, it throws errors sometimes + // Verify that the changeset has valid syntax and is in canonical form Changeset.checkRep(changeset); - + + // Verify that the attribute indexes used in the changeset are all + // defined in the accompanying attribute pool. Changeset.eachAttribNumber(changeset, function(n) { if (! wireApool.getAttrib(n)) { throw "Attribute pool is missing attribute "+n+" for changeset "+changeset; } }); } - //there is an error in this changeset, so just refuse it catch(e) { - console.warn("Can't apply USER_CHANGES "+changeset+", cause it faild checkRep"); + // There is an error in this changeset, so just refuse it + console.warn("Can't apply USER_CHANGES "+changeset+", because it failed checkRep"); client.json.send({disconnect:"badChangeset"}); return; } @@ -515,7 +523,10 @@ function handleUserChanges(client, message) //ex. applyUserChanges apool = pad.pool; r = baseRev; - + + // The client's changeset might not be based on the latest revision, + // since other clients are sending changes at the same time. + // Update the changeset so that it can be applied to the latest revision. //https://github.com/caolan/async#whilst async.whilst( function() { return r < pad.getHeadRevisionNumber(); }, @@ -526,8 +537,13 @@ function handleUserChanges(client, message) pad.getRevisionChangeset(r, function(err, c) { if(ERR(err, callback)) return; - + + // At this point, both "c" (from the pad) and "changeset" (from the + // client) are relative to revision r - 1. The follow function + // rebases "changeset" so that it is relative to revision r + // and can be applied after "c". changeset = Changeset.follow(c, changeset, false, apool); + if ((r - baseRev) % 200 == 0) { // don't let the stack get too deep async.nextTick(callback); } else { @@ -558,7 +574,8 @@ function handleUserChanges(client, message) if (correctionChangeset) { pad.appendRevision(correctionChangeset); } - + + // Make sure the pad always ends with an empty line. if (pad.text().lastIndexOf("\n\n") != pad.text().length-2) { var nlChangeset = Changeset.makeSplice(pad.text(), pad.text().length-1, 0, "\n"); pad.appendRevision(nlChangeset); |