storage: Add OfflineSession object to backend storage.

storage/storage.go

@@ -52,6 +52,7 @@ type Storage interface {
 	CreateAuthCode(c AuthCode) error
 	CreateRefresh(r RefreshToken) error
 	CreatePassword(p Password) error
+	CreateOfflineSessions(s OfflineSessions) error
 
 	// TODO(ericchiang): return (T, bool, error) so we can indicate not found
 	// requests that way instead of using ErrNotFound.
@@ -61,6 +62,7 @@ type Storage interface {
 	GetKeys() (Keys, error)
 	GetRefresh(id string) (RefreshToken, error)
 	GetPassword(email string) (Password, error)
+	GetOfflineSessions(userID string, connID string) (OfflineSessions, error)
 
 	ListClients() ([]Client, error)
 	ListRefreshTokens() ([]RefreshToken, error)
@@ -72,6 +74,7 @@ type Storage interface {
 	DeleteClient(id string) error
 	DeleteRefresh(id string) error
 	DeletePassword(email string) error
+	DeleteOfflineSessions(userID string, connID string) error
 
 	// Update methods take a function for updating an object then performs that update within
 	// a transaction. "updater" functions may be called multiple times by a single update call.
@@ -92,6 +95,7 @@ type Storage interface {
 	UpdateAuthRequest(id string, updater func(a AuthRequest) (AuthRequest, error)) error
 	UpdateRefreshToken(id string, updater func(r RefreshToken) (RefreshToken, error)) error
 	UpdatePassword(email string, updater func(p Password) (Password, error)) error
+	UpdateOfflineSessions(userID string, connID string, updater func(s OfflineSessions) (OfflineSessions, error)) error
 
 	// GarbageCollect deletes all expired AuthCodes and AuthRequests.
 	GarbageCollect(now time.Time) (GCResult, error)
@@ -241,6 +245,30 @@ type RefreshToken struct {
 	Nonce string
 }
 
+// RefreshTokenRef is a reference object that contains metadata about refresh tokens.
+type RefreshTokenRef struct {
+	ID string
+
+	// Client the refresh token is valid for.
+	ClientID string
+
+	CreatedAt time.Time
+	LastUsed  time.Time
+}
+
+// OfflineSessions objects are sessions pertaining to users with refresh tokens.
+type OfflineSessions struct {
+	// UserID of an end user who has logged in to the server.
+	UserID string
+
+	// The ID of the connector used to login the user.
+	ConnID string
+
+	// Refresh is a hash table of refresh token reference objects
+	// indexed by the ClientID of the refresh token.
+	Refresh map[string]*RefreshTokenRef
+}
+
 // Password is an email to password mapping managed by the storage.
 type Password struct {
 	// Email and identifying name of the password. Emails are assumed to be valid and