Merge branch 'master' into advanced-trails

1 files changed, 81 insertions, 16 deletions

diff --git a/src/server/websocket.ts b/src/server/websocket.ts
index a11d20cfa..be5cdb202 100644
--- a/src/server/websocket.ts
+++ b/src/server/websocket.ts
@@ -18,6 +18,7 @@ import { DocumentsCollection } from './IDatabase';
 import { Diff, GestureContent, MessageStore, MobileDocumentUploadContent, MobileInkOverlayContent, Transferable, Types, UpdateMobileInkOverlayPositionContent, YoutubeQueryInput, YoutubeQueryTypes } from './Message';
 import { Search } from './Search';
 import { resolvedPorts } from './server_Initialization';
+var _ = require('lodash');
 
 export namespace WebSocket {
     export let _socket: Socket;
@@ -51,7 +52,7 @@ export namespace WebSocket {
                 next();
             });
 
-            socket.emit(MessageStore.UpdateStats.Message, DashStats.getUpdatedStatsBundle())
+            socket.emit(MessageStore.UpdateStats.Message, DashStats.getUpdatedStatsBundle());
 
             // convenience function to log server messages on the client
             function log(message?: any, ...optionalParams: any[]) {
@@ -104,14 +105,12 @@ export namespace WebSocket {
             socket.on('disconnect', function () {
                 let currentUser = socketMap.get(socket);
                 if (!(currentUser === undefined)) {
-                    let currentUsername = currentUser.split(' ')[0]
+                    let currentUsername = currentUser.split(' ')[0];
                     DashStats.logUserLogout(currentUsername, socket);
-                    delete timeMap[currentUsername]
+                    delete timeMap[currentUsername];
                 }
             });
 
-
-
             Utils.Emit(socket, MessageStore.Foo, 'handshooken');
 
             Utils.AddServerHandler(socket, MessageStore.Bar, guid => barReceived(socket, guid));
@@ -146,10 +145,10 @@ export namespace WebSocket {
             };
         });
 
-        setInterval(function() {
+        setInterval(function () {
             // Utils.Emit(socket, MessageStore.UpdateStats, DashStats.getUpdatedStatsBundle());
 
-            io.emit(MessageStore.UpdateStats.Message, DashStats.getUpdatedStatsBundle())
+            io.emit(MessageStore.UpdateStats.Message, DashStats.getUpdatedStatsBundle());
         }, DashStats.SAMPLING_INTERVAL);
     }
 
@@ -193,7 +192,7 @@ export namespace WebSocket {
     }
 
     function barReceived(socket: SocketIO.Socket, userEmail: string) {
-         clients[userEmail] = new Client(userEmail.toString());
+        clients[userEmail] = new Client(userEmail.toString());
         const currentdate = new Date();
         const datetime = currentdate.getDate() + '/' + (currentdate.getMonth() + 1) + '/' + currentdate.getFullYear() + ' @ ' + currentdate.getHours() + ':' + currentdate.getMinutes() + ':' + currentdate.getSeconds();
         console.log(blue(`user ${userEmail} has connected to the web socket at: ${datetime}`));
@@ -319,16 +318,79 @@ export namespace WebSocket {
         );
     }
 
+    /**
+     * findClosestIndex() is a helper function that will try to find
+     * the closest index of a list that has the same value as
+     * a specified argument/index pair.
+     * @param list the list to search through
+     * @param indexesToDelete a list of indexes that are already marked for deletion
+     * so they will be ignored
+     * @param value the value of the item to remove
+     * @param hintIndex the index that the element was at on the client's copy of
+     * the data
+     * @returns the closest index with the same value or -1 if the element was not found.
+     */
+    function findClosestIndex(list: any, indexesToDelete: number[], value: any, hintIndex: number) {
+        let closestIndex = -1;
+        for (let i = 0; i < list.length; i++) {
+            if (list[i] === value && !indexesToDelete.includes(i)) {
+                if (Math.abs(i - hintIndex) < Math.abs(closestIndex - hintIndex)) {
+                    closestIndex = i;
+                }
+            }
+        }
+        return closestIndex;
+    }
+
+    /**
+     * remFromListField() receives the items to remove and a hint
+     * from the client, and attempts to make the modification to the
+     * server's copy of the data. If server's copy does not match
+     * the client's after removal, the server will SEND BACk
+     * its version to the client.
+     * @param socket the socket that the client is connected on
+     * @param diff an object containing the items to remove and a hint
+     * (the hint contains start index and deleteCount, the number of
+     * items to delete)
+     * @param curListItems the server's current copy of the data
+     */
     function remFromListField(socket: Socket, diff: Diff, curListItems?: Transferable): void {
         diff.diff.$set = diff.diff.$remFromSet;
         delete diff.diff.$remFromSet;
         const updatefield = Array.from(Object.keys(diff.diff.$set))[0];
         const remListItems = diff.diff.$set[updatefield].fields;
         const curList = (curListItems as any)?.fields?.[updatefield.replace('fields.', '')]?.fields.filter((f: any) => f !== null) || [];
-        diff.diff.$set[updatefield].fields = curList?.filter(
-            (curItem: any) => !remListItems.some((remItem: any) => (remItem.fieldId ? remItem.fieldId === curItem.fieldId :
-                 remItem.heading ? remItem.heading === curItem.heading : remItem === curItem))
-        );
+        const hint = diff.diff.$set.hint;
+
+        if (hint) {
+            // indexesToRemove stores the indexes that we mark for deletion, which is later used to filter the list (delete the elements)
+            let indexesToRemove: number[] = [];
+            for (let i = 0; i < hint.deleteCount; i++) {
+                if (curList.length > i + hint.start && _.isEqual(curList[i + hint.start], remListItems[i])) {
+                    indexesToRemove.push(i + hint.start);
+                    continue;
+                }
+
+                let closestIndex = findClosestIndex(curList, indexesToRemove, remListItems[i], i + hint.start);
+                if (closestIndex !== -1) {
+                    indexesToRemove.push(closestIndex);
+                } else {
+                    console.log('Item to delete was not found - index = -1');
+                }
+            }
+
+            diff.diff.$set[updatefield].fields = curList?.filter((curItem: any, index: number) => !indexesToRemove.includes(index));
+        } else {
+            // go back to the original way to delete if we didn't receive
+            // a hint from the client
+            diff.diff.$set[updatefield].fields = curList?.filter(
+                (curItem: any) => !remListItems.some((remItem: any) => (remItem.fieldId ? remItem.fieldId === curItem.fieldId : remItem.heading ? remItem.heading === curItem.heading : remItem === curItem))
+            );
+        }
+
+        // if the client and server have different versions of the data after
+        // deletion, they will have different lengths and the server will
+        // send its version of the data to the client
         const sendBack = diff.diff.length !== diff.diff.$set[updatefield].fields.length;
         delete diff.diff.length;
         Database.Instance.update(
@@ -336,6 +398,7 @@ export namespace WebSocket {
             diff.diff,
             () => {
                 if (sendBack) {
+                    // the two copies are different, so the server sends its copy.
                     console.log('SEND BACK');
                     const id = socket.id;
                     socket.id = '';
@@ -373,9 +436,11 @@ export namespace WebSocket {
     var CurUser: string | undefined = undefined;
 
     function UpdateField(socket: Socket, diff: Diff) {
-        let currentUsername = socketMap.get(socket)!.split(' ')[0];
+        const curUser = socketMap.get(socket);
+        if (!curUser) return;
+        let currentUsername = curUser.split(' ')[0];
         userOperations.set(currentUsername, userOperations.get(currentUsername) !== undefined ? userOperations.get(currentUsername)! + 1 : 0);
-        
+
         if (CurUser !== socketMap.get(socket)) {
             CurUser = socketMap.get(socket);
             console.log('Switch User: ' + CurUser);
@@ -411,8 +476,8 @@ export namespace WebSocket {
                 if (term !== undefined) {
                     const { suffix, value } = term;
                     update[key + suffix] = { set: value };
-                    if (key.endsWith('lastModified')) {
-                        update['lastModified' + suffix] = value;
+                    if (key.endsWith('modificationDate')) {
+                        update['modificationDate' + suffix] = value;
                     }
                 }
             }