diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/fields/List.ts | 8 | ||||
| -rw-r--r-- | src/fields/util.ts | 2 | ||||
| -rw-r--r-- | src/server/websocket.ts | 75 |
3 files changed, 80 insertions, 5 deletions
diff --git a/src/fields/List.ts b/src/fields/List.ts index e33627be5..dfd24cf7a 100644 --- a/src/fields/List.ts +++ b/src/fields/List.ts @@ -77,10 +77,16 @@ const listHandlers: any = { item[OnUpdate] = updateFunction(list, i + start, item, this); } } + let hintArray: {val : any, index : number}[] = []; + for(let i = start; i < start + deleteCount; i++) { + hintArray.push({val : list.__fields[i], index : i}); + } const res = list.__fields.splice(start, deleteCount, ...items); + // the hint object sends the starting index of the slice and the number + // of elements to delete. this[Update]( items.length === 0 && deleteCount - ? { op: '$remFromSet', items: removed, length: list.__fields.length } + ? { op: '$remFromSet', items: removed, hint : { start : start, deleteCount : deleteCount }, length: list.__fields.length } : items.length && !deleteCount && start === list.__fields.length ? { op: '$addToSet', items, length: list.__fields.length } : undefined diff --git a/src/fields/util.ts b/src/fields/util.ts index 92f3a69eb..d5b55867e 100644 --- a/src/fields/util.ts +++ b/src/fields/util.ts @@ -377,7 +377,7 @@ export function updateFunction(target: any, prop: any, value: any, receiver: any diff?.op === '$addToSet' ? { $addToSet: { ['fields.' + prop]: SerializationHelper.Serialize(new List<Doc>(diff.items)) } } : diff?.op === '$remFromSet' - ? { $remFromSet: { ['fields.' + prop]: SerializationHelper.Serialize(new List<Doc>(diff.items)) } } + ? { $remFromSet: { ['fields.' + prop]: SerializationHelper.Serialize(new List<Doc>(diff.items)), hint : diff.hint } } : { $set: { ['fields.' + prop]: SerializationHelper.Serialize(value) } }; !op.$set && ((op as any).length = diff.length); const prevValue = ObjectField.MakeCopy(lastValue as List<any>); diff --git a/src/server/websocket.ts b/src/server/websocket.ts index 2acdaa5a3..e94b48f4f 100644 --- a/src/server/websocket.ts +++ b/src/server/websocket.ts @@ -317,15 +317,83 @@ 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.$set.hint; + + + if(hint) { + // indexesToRemove stores the indexes that we mark for deletion, which is later used to filter the list (delete the elements) + let indexesToRemove: number[] = []; + for(let i = 0; i < hint.deleteCount; i++) { + if(curList[i + hint.start] == remListItems[i]) { + indexesToRemove.push(i + hint.start); + continue; + } + + let closestIndex = findClosestIndex(curList, indexesToRemove, remListItems[i], i + hint.start); + if(closestIndex != -1) { + indexesToRemove.push(closestIndex); + } else { + console.log("Item to delete was not found - index = -1"); + } + } + + diff.diff.$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( @@ -333,6 +401,7 @@ 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 = ''; |