Link to Patch: https://gist.github.com/HotSushi/1b8b5086405be091ee86
Introducing Version : This patch introduces version-ing in document. Date: 23-June-2014 Previous Patch: vehicle.patch (Updated to provide features below) Author: Sushant Raikar Note: Ignore all printf's, they are added temporarily for debugging purpose, and will be removed once the patch is finalized. Working: If there is a laggy connection, the documents at the 2 ends may not always be in the same state. So a LFUN, by the time it reaches the other end, may have to be dispatched on a different state of document, hence leading to ambiguity. In order to handle this, a document is given a version. And each LFUN is targeted at a specific version of document. A history table is maintained which tracks cursor change after any LFUN dispatch. When a remote LFUN is received, it is adjusted based on the history (to predict where the cursor should be in the latest revision). Naturally,if one cursor position is behind another 'editing' cursor position, it is unchanged. If it is in front, then it has to be adjusted. Another important point to note is that, the LFUNs for cursor movements(move-right, move-left) are not sent to remote, only the important editing LFUNs (ex character insert, delete, table insert etc) are sent along with the cursor position where they are dispatched. This approach provides several advantages: - unnecessary version change - less network traffic - immune to different window sizes (LFUNs for mouse_click,home, end, pageup etc. will work) Features: * local cursor moves based on remote dispatch (unlike in previous patch where local cursor was staying stationary) * History queue added, each LFUN sent over dispatches on the targeted version of the document (consistency) * adjusting of cursor based on history queue (neglect changes due to self) * 2 DocIterator's can be subtracted and added back. * each client is identified by a client_id Shortcomings: * no version synchronization. When client connects their buffer is in 'version 0'. All incoming LFUNs are adjusted from version 0. How to handle, at certain time the two ends should synchronize, and the cursor will have to be adjusted from version i, instead of 0. (less looping) * doesn't handle when editing takes place at same cursor location at both ends. How to handle, each client is prioritized, higher priority client stays in its location, lower priority client moves.
