Remove NextBatchStorer/FilterStorer. Replace with Storer

client.go

@@ -38,6 +38,7 @@ type Client struct {
 	syncingID     uint32       // Identifies the current Sync. Only one Sync can be active at any given time.
 	Client        *http.Client // The underlying HTTP client which will be used to make HTTP requests.
 	Syncer        Syncer       // The thing which can process /sync responses
+	Store         Storer       // The thing which can store rooms/tokens/ids
 }
 
 // HTTPError An HTTP Error response, which may wrap an underlying native Go Error.
@@ -96,16 +97,16 @@ func (cli *Client) Sync() error {
 	// We will keep syncing until the syncing state changes. Either because
 	// Sync is called or StopSync is called.
 	syncingID := cli.incrementSyncingID()
-	nextBatch := cli.Syncer.NextBatchStorer().LoadNextBatch(cli.UserID)
-	filterID := cli.Syncer.FilterStorer().LoadFilter(cli.UserID)
+	nextBatch := cli.Store.LoadNextBatch(cli.UserID)
+	filterID := cli.Store.LoadFilterID(cli.UserID)
 	if filterID == "" {
-		filterJSON := cli.Syncer.FilterStorer().GetFilterJSON(cli.UserID)
+		filterJSON := cli.Syncer.GetFilterJSON(cli.UserID)
 		resFilter, err := cli.CreateFilter(filterJSON)
 		if err != nil {
 			return err
 		}
 		filterID = resFilter.FilterID
-		cli.Syncer.FilterStorer().SaveFilter(cli.UserID, filterID)
+		cli.Store.SaveFilterID(cli.UserID, filterID)
 	}
 
 	for {
@@ -129,7 +130,7 @@ func (cli *Client) Sync() error {
 		// Save the token now *before* processing it. This means it's possible
 		// to not process some events, but it means that we won't get constantly stuck processing
 		// a malformed/buggy event which keeps making us panic.
-		cli.Syncer.NextBatchStorer().SaveNextBatch(cli.UserID, resSync.NextBatch)
+		cli.Store.SaveNextBatch(cli.UserID, resSync.NextBatch)
 		if err = cli.Syncer.ProcessResponse(resSync, nextBatch); err != nil {
 			return err
 		}
@@ -243,25 +244,17 @@ func NewClient(homeserverURL, userID, accessToken string) (*Client, error) {
 	if err != nil {
 		return nil, err
 	}
+	// By default, use an in-memory store which will never save filter ids / next batch tokens to disk.
+	// The client will work with this storer: it just won't remember across restarts.
+	// In practice, a database backend should be used.
+	store := NewInMemoryStore()
 	cli := Client{
 		AccessToken:   accessToken,
 		HomeserverURL: hsURL,
 		UserID:        userID,
 		Prefix:        "/_matrix/client/r0",
-		Syncer: NewDefaultSyncer(
-			userID,
-			// By default, use an in-memory next_batch storer which will never save tokens to disk.
-			// The client will work with this storer: it just won't
-			// remember the token across restarts. In practice, a database backend should be used.
-			&InMemoryNextBatchStore{make(map[string]string)},
-			// By default, use an in-memory filter storer which will never save the filter ID to disk.
-			// The client will work with this storer: it just won't remember the filter
-			// ID across restarts and hence request a new one. In practice, a database backend should be used.
-			&InMemoryFilterStore{
-				Filter:       json.RawMessage(`{"room":{"timeline":{"limit":50}}}`),
-				UserToFilter: make(map[string]string),
-			},
-		),
+		Syncer:        NewDefaultSyncer(userID, store),
+		Store:         store,
 	}
 	// By default, use the default HTTP client.
 	cli.Client = http.DefaultClient

store.go

@@ -0,0 +1,51 @@
+package gomatrix
+
+// Storer is an interface which must be satisfied to store client data.
+//
+// You can either write a struct which persists this data to disk, or you can use the
+// provided "InMemoryStore" which just keeps data around in-memory which is lost on
+// restarts.
+type Storer interface {
+	SaveFilterID(userID, filterID string)
+	LoadFilterID(userID string) string
+	SaveNextBatch(userID, nextBatchToken string)
+	LoadNextBatch(userID string) string
+}
+
+// InMemoryStore implements the Storer interface.
+//
+// Everything is persisted in-memory as maps. It is not safe to load/save filter IDs
+// or next batch tokens on any goroutine other than the syncing goroutine: the one
+// which called Client.Sync().
+type InMemoryStore struct {
+	Filters   map[string]string
+	NextBatch map[string]string
+}
+
+// SaveFilterID to memory.
+func (s *InMemoryStore) SaveFilterID(userID, filterID string) {
+	s.Filters[userID] = filterID
+}
+
+// LoadFilterID from memory.
+func (s *InMemoryStore) LoadFilterID(userID string) string {
+	return s.Filters[userID]
+}
+
+// SaveNextBatch to memory.
+func (s *InMemoryStore) SaveNextBatch(userID, nextBatchToken string) {
+	s.NextBatch[userID] = nextBatchToken
+}
+
+// LoadNextBatch from memory.
+func (s *InMemoryStore) LoadNextBatch(userID string) string {
+	return s.NextBatch[userID]
+}
+
+// NewInMemoryStore constructs a new InMemoryStore.
+func NewInMemoryStore() *InMemoryStore {
+	return &InMemoryStore{
+		Filters:   make(map[string]string),
+		NextBatch: make(map[string]string),
+	}
+}

sync.go

@@ -13,35 +13,31 @@ type Syncer interface {
 	// This is useful for detecting the very first sync (since=""). If an error is return, Syncing will be stopped
 	// permanently.
 	ProcessResponse(resp *RespSync, since string) error
-	// Interface for saving and loading the "next_batch" sync token.
-	NextBatchStorer() NextBatchStorer
-	// Interface for saving and loading the filter ID for sync.
-	FilterStorer() FilterStorer
 	// OnFailedSync returns either the time to wait before retrying or an error to stop syncing permanently.
 	OnFailedSync(res *RespSync, err error) (time.Duration, error)
+	// GetFilterJSON for the given user ID. NOT the filter ID.
+	GetFilterJSON(userID string) json.RawMessage
 }
 
 // DefaultSyncer is the default syncing implementation. You can either write your own syncer, or selectively
 // replace parts of this default syncer (e.g. the NextBatch/Filter storers, or the ProcessResponse method).
 type DefaultSyncer struct {
-	UserID         string
-	Rooms          map[string]*Room
-	NextBatchStore NextBatchStorer
-	FilterStore    FilterStorer
-	listeners      map[string][]OnEventListener // event type to listeners array
+	UserID    string
+	Rooms     map[string]*Room
+	Store     Storer
+	listeners map[string][]OnEventListener // event type to listeners array
 }
 
 // OnEventListener can be used with DefaultSyncer.OnEventType to be informed of incoming events.
 type OnEventListener func(*Event)
 
 // NewDefaultSyncer returns an instantiated DefaultSyncer
-func NewDefaultSyncer(userID string, nextBatch NextBatchStorer, filterStore FilterStorer) *DefaultSyncer {
+func NewDefaultSyncer(userID string, store Storer) *DefaultSyncer {
 	return &DefaultSyncer{
-		UserID:         userID,
-		Rooms:          make(map[string]*Room),
-		NextBatchStore: nextBatch,
-		FilterStore:    filterStore,
-		listeners:      make(map[string][]OnEventListener),
+		UserID:    userID,
+		Rooms:     make(map[string]*Room),
+		Store:     store,
+		listeners: make(map[string][]OnEventListener),
 	}
 }
 
@@ -148,71 +144,12 @@ func (s *DefaultSyncer) notifyListeners(event *Event) {
 	}
 }
 
-// NextBatchStorer returns the provided NextBatchStorer
-func (s *DefaultSyncer) NextBatchStorer() NextBatchStorer {
-	return s.NextBatchStore
-}
-
-// FilterStorer returns the provided FilterStorer
-func (s *DefaultSyncer) FilterStorer() FilterStorer {
-	return s.FilterStore
-}
-
 // OnFailedSync always returns a 10 second wait period between failed /syncs.
 func (s *DefaultSyncer) OnFailedSync(res *RespSync, err error) (time.Duration, error) {
 	return 10 * time.Second, nil
 }
 
-// NextBatchStorer controls loading/saving of next_batch tokens for users
-type NextBatchStorer interface {
-	// SaveNextBatch saves a next_batch token for a given user. Best effort.
-	SaveNextBatch(userID, nextBatch string)
-	// LoadNextBatch loads a next_batch token for a given user. Return an empty string if no token exists.
-	LoadNextBatch(userID string) string
-}
-
-// InMemoryNextBatchStore stores next batch tokens in memory.
-type InMemoryNextBatchStore struct {
-	UserToNextBatch map[string]string
-}
-
-// SaveNextBatch saves the mapping in-memory.
-func (s *InMemoryNextBatchStore) SaveNextBatch(userID, nextBatch string) {
-	s.UserToNextBatch[userID] = nextBatch
-}
-
-// LoadNextBatch loads an existing mapping. Returns an empty string if not found
-func (s *InMemoryNextBatchStore) LoadNextBatch(userID string) string {
-	return s.UserToNextBatch[userID]
-}
-
-// FilterStorer controls loading/saving of filter IDs for users
-type FilterStorer interface {
-	// SaveFilter saves a filter ID for a given user. Best effort.
-	SaveFilter(userID, filterID string)
-	// LoadFilter loads a filter ID for a given user. Return an empty string if no token exists.
-	LoadFilter(userID string) string
-	// GetFilterJSON for the given user ID.
-	GetFilterJSON(userID string) json.RawMessage
-}
-
-// InMemoryFilterStore stores filter IDs in memory. It always returns the filter JSON given in the struct.
-type InMemoryFilterStore struct {
-	Filter       json.RawMessage
-	UserToFilter map[string]string
-}
-
-// SaveFilter saves the user->filter ID mapping in memory
-func (s *InMemoryFilterStore) SaveFilter(userID, filterID string) {
-	s.UserToFilter[userID] = filterID
-}
-
-// LoadFilter loads a previously saved user->filter ID mapping from memory. Returns the empty string if not found.
-func (s *InMemoryFilterStore) LoadFilter(userID string) string {
-	return s.UserToFilter[userID]
-}
-
-// GetFilterJSON returns InMemoryFilterStore.Filter
-func (s *InMemoryFilterStore) GetFilterJSON(userID string) json.RawMessage {
-	return s.Filter
+// GetFilterJSON returns a filter with a timeline limit of 50.
+func (s *DefaultSyncer) GetFilterJSON(userID string) json.RawMessage {
+	return json.RawMessage(`{"room":{"timeline":{"limit":50}}}`)
 }