Data.Mergeless.Collection

A way to synchronise items without merge conflicts.

This concept has a few requirements:

• Items must be immutable.
• Items must allow for a centrally unique identifier.
• Identifiers for items must be generatable in such a way that they are certainly unique.

Should mutation be a requirement, then it can be build such that it entails deleting the old version and creating a new version that is the modification of the old version.

There are a few obvious candidates for identifiers:

• incremental identifiers
• universally unique identifiers (recommended).

The typical setup is as follows:

• A central server is set up to synchronise with
• Each client synchronises with the central server, but never with eachother

A central server should operate as follows:

• The server accepts a SyncRequest.
• The server performs operations according to the functionality of processServerSync.
• The server respons with a SyncResponse.

A client should operate as follows:

• The client produces a SyncRequest with makeSyncRequest.
• The client sends that request to the central server and gets a SyncResponse.
• The client then updates its local store with mergeSyncResponse.

Documentation

newtype ClientId

A Client-side identifier for items.

These only need to be unique at the client.

Constructors

ClientId

Fields

• unClientId :: Word64

Instances

Bounded ClientId

Defined in Data.Mergeless.Collection

Methods

minBound :: ClientId

maxBound :: ClientId

Enum ClientId

Defined in Data.Mergeless.Collection

Methods

succ :: ClientId -> ClientId

pred :: ClientId -> ClientId

toEnum :: Int -> ClientId

fromEnum :: ClientId -> Int

enumFrom :: ClientId -> [ClientId]

enumFromThen :: ClientId -> ClientId -> [ClientId]

enumFromTo :: ClientId -> ClientId -> [ClientId]

enumFromThenTo :: ClientId -> ClientId -> ClientId -> [ClientId]

Eq ClientId

Defined in Data.Mergeless.Collection

Methods

(==) :: ClientId -> ClientId -> Bool

(/=) :: ClientId -> ClientId -> Bool

Ord ClientId

Defined in Data.Mergeless.Collection

Methods

compare :: ClientId -> ClientId -> Ordering

(<) :: ClientId -> ClientId -> Bool

(<=) :: ClientId -> ClientId -> Bool

(>) :: ClientId -> ClientId -> Bool

(>=) :: ClientId -> ClientId -> Bool

max :: ClientId -> ClientId -> ClientId

min :: ClientId -> ClientId -> ClientId

Show ClientId

Defined in Data.Mergeless.Collection

Methods

showsPrec :: Int -> ClientId -> ShowS

show :: ClientId -> String

showList :: [ClientId] -> ShowS

Generic ClientId

Defined in Data.Mergeless.Collection

Associated Types

type Rep ClientId :: Type -> Type

Methods

from :: ClientId -> Rep ClientId x

to :: Rep ClientId x -> ClientId

ToJSON ClientId

Defined in Data.Mergeless.Collection

Methods

toJSON :: ClientId -> Value

toEncoding :: ClientId -> Encoding

toJSONList :: [ClientId] -> Value

toEncodingList :: [ClientId] -> Encoding

ToJSONKey ClientId

Defined in Data.Mergeless.Collection

Methods

toJSONKey :: ToJSONKeyFunction ClientId

toJSONKeyList :: ToJSONKeyFunction [ClientId]

FromJSON ClientId

Defined in Data.Mergeless.Collection

Methods

parseJSON :: Value -> Parser ClientId

parseJSONList :: Value -> Parser [ClientId]

FromJSONKey ClientId

Defined in Data.Mergeless.Collection

Methods

fromJSONKey :: FromJSONKeyFunction ClientId

fromJSONKeyList :: FromJSONKeyFunction [ClientId]

NFData ClientId

Defined in Data.Mergeless.Collection

Methods

rnf :: ClientId -> ()

Validity ClientId

Defined in Data.Mergeless.Collection

Methods

validate :: ClientId -> Validation

type Rep ClientId

Defined in Data.Mergeless.Collection

type Rep ClientId = D1 (MetaData "ClientId" "Data.Mergeless.Collection" "mergeless-0.2.0.1-EJEJ0UxqAftGrZfjWZKWS3" True) (C1 (MetaCons "ClientId" PrefixI True) (S1 (MetaSel (Just "unClientId") NoSourceUnpackedness NoSourceStrictness DecidedLazy) (Rec0 Word64)))

data ClientStore i a

A client-side store of items with Id's of type i and values of type a

Constructors

ClientStore

Fields

• clientStoreAdded :: !(Map ClientId a)
• clientStoreSynced :: !(Map i a)
• clientStoreDeleted :: !(Set i)

Instances

(Eq a, Eq i) => Eq (ClientStore i a)

Defined in Data.Mergeless.Collection

Methods

(==) :: ClientStore i a -> ClientStore i a -> Bool

(/=) :: ClientStore i a -> ClientStore i a -> Bool

(Ord a, Ord i) => Ord (ClientStore i a)

Defined in Data.Mergeless.Collection

Methods

compare :: ClientStore i a -> ClientStore i a -> Ordering

(<) :: ClientStore i a -> ClientStore i a -> Bool

(<=) :: ClientStore i a -> ClientStore i a -> Bool

(>) :: ClientStore i a -> ClientStore i a -> Bool

(>=) :: ClientStore i a -> ClientStore i a -> Bool

max :: ClientStore i a -> ClientStore i a -> ClientStore i a

min :: ClientStore i a -> ClientStore i a -> ClientStore i a

(Show a, Show i) => Show (ClientStore i a)

Defined in Data.Mergeless.Collection

Methods

showsPrec :: Int -> ClientStore i a -> ShowS

show :: ClientStore i a -> String

showList :: [ClientStore i a] -> ShowS

Generic (ClientStore i a)

Defined in Data.Mergeless.Collection

Associated Types

type Rep (ClientStore i a) :: Type -> Type

Methods

from :: ClientStore i a -> Rep (ClientStore i a) x

to :: Rep (ClientStore i a) x -> ClientStore i a

(Ord i, ToJSON i, ToJSONKey i, ToJSON a) => ToJSON (ClientStore i a)

Defined in Data.Mergeless.Collection

Methods

toJSON :: ClientStore i a -> Value

toEncoding :: ClientStore i a -> Encoding

toJSONList :: [ClientStore i a] -> Value

toEncodingList :: [ClientStore i a] -> Encoding

(Ord i, FromJSON i, FromJSONKey i, FromJSON a) => FromJSON (ClientStore i a)

Defined in Data.Mergeless.Collection

Methods

parseJSON :: Value -> Parser (ClientStore i a)

parseJSONList :: Value -> Parser [ClientStore i a]

(NFData i, NFData a) => NFData (ClientStore i a)

Defined in Data.Mergeless.Collection

Methods

rnf :: ClientStore i a -> ()

(Validity i, Validity a, Show i, Show a, Ord i, Ord a) => Validity (ClientStore i a)

Defined in Data.Mergeless.Collection

Methods

validate :: ClientStore i a -> Validation

type Rep (ClientStore i a)

Defined in Data.Mergeless.Collection

type Rep (ClientStore i a) = D1 (MetaData "ClientStore" "Data.Mergeless.Collection" "mergeless-0.2.0.1-EJEJ0UxqAftGrZfjWZKWS3" False) (C1 (MetaCons "ClientStore" PrefixI True) (S1 (MetaSel (Just "clientStoreAdded") NoSourceUnpackedness SourceStrict DecidedStrict) (Rec0 (Map ClientId a)) :*: (S1 (MetaSel (Just "clientStoreSynced") NoSourceUnpackedness SourceStrict DecidedStrict) (Rec0 (Map i a)) :*: S1 (MetaSel (Just "clientStoreDeleted") NoSourceUnpackedness SourceStrict DecidedStrict) (Rec0 (Set i)))))

emptyClientStore :: ClientStore i a

The store with no items.

storeSize :: ClientStore i a -> Int

The number of items in a store

This does not count the deleted items, so that those really look deleted.

addItemToClientStore :: (Ord i, Ord a) => a -> ClientStore i a -> ClientStore i a

Add an item to a client store as an added item.

This will take care of the uniqueness constraint of the ClientIds in the map.

deleteUnsyncedFromClientStore :: (Ord i, Ord a) => ClientId -> ClientStore i a -> ClientStore i a

deleteSyncedFromClientStore :: (Ord i, Ord a) => i -> ClientStore i a -> ClientStore i a

data SyncRequest i a

A synchronisation request for items with identifiers of type i and values of type a

Constructors

SyncRequest

Fields

• syncRequestAdded :: !(Map ClientId a)
• syncRequestSynced :: !(Set i)
• syncRequestDeleted :: !(Set i)

Instances

(Eq a, Eq i) => Eq (SyncRequest i a)

Defined in Data.Mergeless.Collection

Methods

(==) :: SyncRequest i a -> SyncRequest i a -> Bool

(/=) :: SyncRequest i a -> SyncRequest i a -> Bool

(Ord a, Ord i) => Ord (SyncRequest i a)

Defined in Data.Mergeless.Collection

Methods

compare :: SyncRequest i a -> SyncRequest i a -> Ordering

(<) :: SyncRequest i a -> SyncRequest i a -> Bool

(<=) :: SyncRequest i a -> SyncRequest i a -> Bool

(>) :: SyncRequest i a -> SyncRequest i a -> Bool

(>=) :: SyncRequest i a -> SyncRequest i a -> Bool

max :: SyncRequest i a -> SyncRequest i a -> SyncRequest i a

min :: SyncRequest i a -> SyncRequest i a -> SyncRequest i a

(Show a, Show i) => Show (SyncRequest i a)

Defined in Data.Mergeless.Collection

Methods

showsPrec :: Int -> SyncRequest i a -> ShowS

show :: SyncRequest i a -> String

showList :: [SyncRequest i a] -> ShowS

Generic (SyncRequest i a)

Defined in Data.Mergeless.Collection

Associated Types

type Rep (SyncRequest i a) :: Type -> Type

Methods

from :: SyncRequest i a -> Rep (SyncRequest i a) x

to :: Rep (SyncRequest i a) x -> SyncRequest i a

(ToJSON i, ToJSON a) => ToJSON (SyncRequest i a)

Defined in Data.Mergeless.Collection

Methods

toJSON :: SyncRequest i a -> Value

toEncoding :: SyncRequest i a -> Encoding

toJSONList :: [SyncRequest i a] -> Value

toEncodingList :: [SyncRequest i a] -> Encoding

(FromJSON i, FromJSON a, Ord i, Ord a) => FromJSON (SyncRequest i a)

Defined in Data.Mergeless.Collection

Methods

parseJSON :: Value -> Parser (SyncRequest i a)

parseJSONList :: Value -> Parser [SyncRequest i a]

(NFData i, NFData a) => NFData (SyncRequest i a)

Defined in Data.Mergeless.Collection

Methods

rnf :: SyncRequest i a -> ()

(Validity i, Validity a, Ord i, Ord a) => Validity (SyncRequest i a)

Defined in Data.Mergeless.Collection

Methods

validate :: SyncRequest i a -> Validation

type Rep (SyncRequest i a)

Defined in Data.Mergeless.Collection

type Rep (SyncRequest i a) = D1 (MetaData "SyncRequest" "Data.Mergeless.Collection" "mergeless-0.2.0.1-EJEJ0UxqAftGrZfjWZKWS3" False) (C1 (MetaCons "SyncRequest" PrefixI True) (S1 (MetaSel (Just "syncRequestAdded") NoSourceUnpackedness SourceStrict DecidedStrict) (Rec0 (Map ClientId a)) :*: (S1 (MetaSel (Just "syncRequestSynced") NoSourceUnpackedness SourceStrict DecidedStrict) (Rec0 (Set i)) :*: S1 (MetaSel (Just "syncRequestDeleted") NoSourceUnpackedness SourceStrict DecidedStrict) (Rec0 (Set i)))))

data SyncResponse i a

A synchronisation response for items with identifiers of type i and values of type a

Constructors

SyncResponse

Fields

• syncResponseClientAdded :: !(Map ClientId i)
• syncResponseClientDeleted :: !(Set i)
• syncResponseServerAdded :: !(Map i a)
• syncResponseServerDeleted :: !(Set i)

Instances

(Eq i, Eq a) => Eq (SyncResponse i a)

Defined in Data.Mergeless.Collection

Methods

(==) :: SyncResponse i a -> SyncResponse i a -> Bool

(/=) :: SyncResponse i a -> SyncResponse i a -> Bool

(Ord i, Ord a) => Ord (SyncResponse i a)

Defined in Data.Mergeless.Collection

Methods

compare :: SyncResponse i a -> SyncResponse i a -> Ordering

(<) :: SyncResponse i a -> SyncResponse i a -> Bool

(<=) :: SyncResponse i a -> SyncResponse i a -> Bool

(>) :: SyncResponse i a -> SyncResponse i a -> Bool

(>=) :: SyncResponse i a -> SyncResponse i a -> Bool

max :: SyncResponse i a -> SyncResponse i a -> SyncResponse i a

min :: SyncResponse i a -> SyncResponse i a -> SyncResponse i a

(Show i, Show a) => Show (SyncResponse i a)

Defined in Data.Mergeless.Collection

Methods

showsPrec :: Int -> SyncResponse i a -> ShowS

show :: SyncResponse i a -> String

showList :: [SyncResponse i a] -> ShowS

Generic (SyncResponse i a)

Defined in Data.Mergeless.Collection

Associated Types

type Rep (SyncResponse i a) :: Type -> Type

Methods

from :: SyncResponse i a -> Rep (SyncResponse i a) x

to :: Rep (SyncResponse i a) x -> SyncResponse i a

(ToJSON i, ToJSONKey i, ToJSON a) => ToJSON (SyncResponse i a)

Defined in Data.Mergeless.Collection

Methods

toJSON :: SyncResponse i a -> Value

toEncoding :: SyncResponse i a -> Encoding

toJSONList :: [SyncResponse i a] -> Value

toEncodingList :: [SyncResponse i a] -> Encoding

(Ord i, FromJSON i, FromJSONKey i, Ord a, FromJSON a) => FromJSON (SyncResponse i a)

Defined in Data.Mergeless.Collection

Methods

parseJSON :: Value -> Parser (SyncResponse i a)

parseJSONList :: Value -> Parser [SyncResponse i a]

(NFData i, NFData a) => NFData (SyncResponse i a)

Defined in Data.Mergeless.Collection

Methods

rnf :: SyncResponse i a -> ()

(Validity i, Validity a, Show i, Show a, Ord i, Ord a) => Validity (SyncResponse i a)

Defined in Data.Mergeless.Collection

Methods

validate :: SyncResponse i a -> Validation

type Rep (SyncResponse i a)

Defined in Data.Mergeless.Collection

type Rep (SyncResponse i a) = D1 (MetaData "SyncResponse" "Data.Mergeless.Collection" "mergeless-0.2.0.1-EJEJ0UxqAftGrZfjWZKWS3" False) (C1 (MetaCons "SyncResponse" PrefixI True) ((S1 (MetaSel (Just "syncResponseClientAdded") NoSourceUnpackedness SourceStrict DecidedStrict) (Rec0 (Map ClientId i)) :*: S1 (MetaSel (Just "syncResponseClientDeleted") NoSourceUnpackedness SourceStrict DecidedStrict) (Rec0 (Set i))) :*: (S1 (MetaSel (Just "syncResponseServerAdded") NoSourceUnpackedness SourceStrict DecidedStrict) (Rec0 (Map i a)) :*: S1 (MetaSel (Just "syncResponseServerDeleted") NoSourceUnpackedness SourceStrict DecidedStrict) (Rec0 (Set i)))))

emptySyncResponse :: SyncResponse i ia

Client-side Synchronisation

makeSyncRequest :: (Ord i, Ord a) => ClientStore i a -> SyncRequest i a

Produce a synchronisation request for a client-side store.

This request can then be sent to a central store for synchronisation.

mergeSyncResponse :: forall i a. (Ord i, Ord a) => ClientStore i a -> SyncResponse i a -> ClientStore i a

Merge a synchronisation response back into a client-side store.

addRemotelyAddedItems :: (Ord i, Ord a) => Map i a -> ClientStore i a -> ClientStore i a

addAddedItems :: forall i a. (Ord i, Ord a) => Map ClientId i -> ClientStore i a -> ClientStore i a

deleteItemsToBeDeletedLocally :: (Ord i, Ord a) => Set i -> ClientStore i a -> ClientStore i a

deleteLocalUndeletedItems :: (Ord i, Ord a) => Set i -> ClientStore i a -> ClientStore i a

Server-side Synchronisation

General synchronisation

data ServerSyncProcessor i a m

A record of the basic operations that are necessary to build a synchronisation processor.

Constructors

ServerSyncProcessor

Fields

• serverSyncProcessorDeleteMany :: Set i -> m (Set i)

  Delete the items with an identifier in the given set, return the set that was indeed deleted or did not exist. In particular, return the identifiers of the items that the client should forget about.

• serverSyncProcessorQueryNoLongerSynced :: Set i -> m (Set i)

  Query the identifiers of the items that are in the given set but not in the store.

• serverSyncProcessorQueryNewRemote :: Set i -> m (Map i a)

  Query the items that are in store, but not in the given set.

• serverSyncProcessorInsertMany :: Map ClientId a -> m (Map ClientId i)

  Insert a set of items into the store.

Instances

Generic (ServerSyncProcessor i a m)

Defined in Data.Mergeless.Collection

Associated Types

type Rep (ServerSyncProcessor i a m) :: Type -> Type

Methods

from :: ServerSyncProcessor i a m -> Rep (ServerSyncProcessor i a m) x

to :: Rep (ServerSyncProcessor i a m) x -> ServerSyncProcessor i a m

type Rep (ServerSyncProcessor i a m)

Defined in Data.Mergeless.Collection

type Rep (ServerSyncProcessor i a m) = D1 (MetaData "ServerSyncProcessor" "Data.Mergeless.Collection" "mergeless-0.2.0.1-EJEJ0UxqAftGrZfjWZKWS3" False) (C1 (MetaCons "ServerSyncProcessor" PrefixI True) ((S1 (MetaSel (Just "serverSyncProcessorDeleteMany") NoSourceUnpackedness NoSourceStrictness DecidedLazy) (Rec0 (Set i -> m (Set i))) :*: S1 (MetaSel (Just "serverSyncProcessorQueryNoLongerSynced") NoSourceUnpackedness NoSourceStrictness DecidedLazy) (Rec0 (Set i -> m (Set i)))) :*: (S1 (MetaSel (Just "serverSyncProcessorQueryNewRemote") NoSourceUnpackedness NoSourceStrictness DecidedLazy) (Rec0 (Set i -> m (Map i a))) :*: S1 (MetaSel (Just "serverSyncProcessorInsertMany") NoSourceUnpackedness NoSourceStrictness DecidedLazy) (Rec0 (Map ClientId a -> m (Map ClientId i))))))

processServerSyncCustom :: forall i a m. (Ord i, Ord a, Monad m) => ServerSyncProcessor i a m -> SyncRequest i a -> m (SyncResponse i a)

Process a server-side synchronisation request using a custom synchronisation processor

WARNING: The identifier generation function must produce newly unique identifiers such that each new item gets a unique identifier.

You can use this function with deterministically-random identifiers or incrementing identifiers.

Synchronisation with a simple central store

newtype ServerStore i a

A central store of items with identifiers of type i and values of type a

Constructors

ServerStore

Fields

• serverStoreItems :: Map i a

Instances

(Eq i, Eq a) => Eq (ServerStore i a)

Defined in Data.Mergeless.Collection

Methods

(==) :: ServerStore i a -> ServerStore i a -> Bool

(/=) :: ServerStore i a -> ServerStore i a -> Bool

(Ord i, Ord a) => Ord (ServerStore i a)

Defined in Data.Mergeless.Collection

Methods

compare :: ServerStore i a -> ServerStore i a -> Ordering

(<) :: ServerStore i a -> ServerStore i a -> Bool

(<=) :: ServerStore i a -> ServerStore i a -> Bool

(>) :: ServerStore i a -> ServerStore i a -> Bool

(>=) :: ServerStore i a -> ServerStore i a -> Bool

max :: ServerStore i a -> ServerStore i a -> ServerStore i a

min :: ServerStore i a -> ServerStore i a -> ServerStore i a

(Show i, Show a) => Show (ServerStore i a)

Defined in Data.Mergeless.Collection

Methods

showsPrec :: Int -> ServerStore i a -> ShowS

show :: ServerStore i a -> String

showList :: [ServerStore i a] -> ShowS

Generic (ServerStore i a)

Defined in Data.Mergeless.Collection

Associated Types

type Rep (ServerStore i a) :: Type -> Type

Methods

from :: ServerStore i a -> Rep (ServerStore i a) x

to :: Rep (ServerStore i a) x -> ServerStore i a

(ToJSON a, ToJSONKey i) => ToJSON (ServerStore i a)

Defined in Data.Mergeless.Collection

Methods

toJSON :: ServerStore i a -> Value

toEncoding :: ServerStore i a -> Encoding

toJSONList :: [ServerStore i a] -> Value

toEncodingList :: [ServerStore i a] -> Encoding

(FromJSONKey i, Ord i, FromJSON a) => FromJSON (ServerStore i a)

Defined in Data.Mergeless.Collection

Methods

parseJSON :: Value -> Parser (ServerStore i a)

parseJSONList :: Value -> Parser [ServerStore i a]

(NFData i, NFData a) => NFData (ServerStore i a)

Defined in Data.Mergeless.Collection

Methods

rnf :: ServerStore i a -> ()

(Validity i, Validity a, Show i, Show a, Ord i, Ord a) => Validity (ServerStore i a)

Defined in Data.Mergeless.Collection

Methods

validate :: ServerStore i a -> Validation

type Rep (ServerStore i a)

Defined in Data.Mergeless.Collection

type Rep (ServerStore i a) = D1 (MetaData "ServerStore" "Data.Mergeless.Collection" "mergeless-0.2.0.1-EJEJ0UxqAftGrZfjWZKWS3" True) (C1 (MetaCons "ServerStore" PrefixI True) (S1 (MetaSel (Just "serverStoreItems") NoSourceUnpackedness NoSourceStrictness DecidedLazy) (Rec0 (Map i a))))

emptyServerStore :: ServerStore i a

An empty central store to start with

processServerSync :: forall m i a. (Ord i, Ord a, Monad m) => m i -> ServerStore i a -> SyncRequest i a -> m (SyncResponse i a, ServerStore i a)

Process a server-side synchronisation request using getCurrentTime

see processSyncCustom