watchtower/wtmock/tower_db: move mock tower db to wtmock pkg

watchtower/wtmock/tower_db.go

@@ -0,0 +1,162 @@
+package wtmock
+
+import (
+	"sync"
+
+	"github.com/lightningnetwork/lnd/chainntnfs"
+	"github.com/lightningnetwork/lnd/watchtower/wtdb"
+)
+
+// TowerDB is a mock, in-memory implementation of a watchtower.DB.
+type TowerDB struct {
+	mu        sync.Mutex
+	lastEpoch *chainntnfs.BlockEpoch
+	sessions  map[wtdb.SessionID]*wtdb.SessionInfo
+	blobs     map[wtdb.BreachHint]map[wtdb.SessionID]*wtdb.SessionStateUpdate
+}
+
+// NewTowerDB initializes a fresh mock TowerDB.
+func NewTowerDB() *TowerDB {
+	return &TowerDB{
+		sessions: make(map[wtdb.SessionID]*wtdb.SessionInfo),
+		blobs:    make(map[wtdb.BreachHint]map[wtdb.SessionID]*wtdb.SessionStateUpdate),
+	}
+}
+
+// InsertStateUpdate stores an update sent by the client after validating that
+// the update is well-formed in the context of other updates sent for the same
+// session. This include verifying that the sequence number is incremented
+// properly and the last applied values echoed by the client are sane.
+func (db *TowerDB) InsertStateUpdate(update *wtdb.SessionStateUpdate) (uint16, error) {
+	db.mu.Lock()
+	defer db.mu.Unlock()
+
+	info, ok := db.sessions[update.ID]
+	if !ok {
+		return 0, wtdb.ErrSessionNotFound
+	}
+
+	err := info.AcceptUpdateSequence(update.SeqNum, update.LastApplied)
+	if err != nil {
+		return info.LastApplied, err
+	}
+
+	sessionsToUpdates, ok := db.blobs[update.Hint]
+	if !ok {
+		sessionsToUpdates = make(map[wtdb.SessionID]*wtdb.SessionStateUpdate)
+		db.blobs[update.Hint] = sessionsToUpdates
+	}
+	sessionsToUpdates[update.ID] = update
+
+	return info.LastApplied, nil
+}
+
+// GetSessionInfo retrieves the session for the passed session id. An error is
+// returned if the session could not be found.
+func (db *TowerDB) GetSessionInfo(id *wtdb.SessionID) (*wtdb.SessionInfo, error) {
+	db.mu.Lock()
+	defer db.mu.Unlock()
+
+	if info, ok := db.sessions[*id]; ok {
+		return info, nil
+	}
+
+	return nil, wtdb.ErrSessionNotFound
+}
+
+// InsertSessionInfo records a negotiated session in the tower database. An
+// error is returned if the session already exists.
+func (db *TowerDB) InsertSessionInfo(info *wtdb.SessionInfo) error {
+	db.mu.Lock()
+	defer db.mu.Unlock()
+
+	dbInfo, ok := db.sessions[info.ID]
+	if ok && dbInfo.LastApplied > 0 {
+		return wtdb.ErrSessionAlreadyExists
+	}
+
+	db.sessions[info.ID] = info
+
+	return nil
+}
+
+// DeleteSession removes all data associated with a particular session id from
+// the tower's database.
+func (db *TowerDB) DeleteSession(target wtdb.SessionID) error {
+	db.mu.Lock()
+	defer db.mu.Unlock()
+
+	// Fail if the session doesn't exit.
+	if _, ok := db.sessions[target]; !ok {
+		return wtdb.ErrSessionNotFound
+	}
+
+	// Remove the target session.
+	delete(db.sessions, target)
+
+	// Remove the state updates for any blobs stored under the target
+	// session identifier.
+	for hint, sessionUpdates := range db.blobs {
+		delete(sessionUpdates, target)
+
+		// If this was the last state update, we can also remove the
+		// hint that would map to an empty set.
+		if len(sessionUpdates) == 0 {
+			delete(db.blobs, hint)
+		}
+	}
+
+	return nil
+}
+
+// QueryMatches searches against all known state updates for any that match the
+// passed breachHints. More than one Match will be returned for a given hint if
+// they exist in the database.
+func (db *TowerDB) QueryMatches(
+	breachHints []wtdb.BreachHint) ([]wtdb.Match, error) {
+
+	db.mu.Lock()
+	defer db.mu.Unlock()
+
+	var matches []wtdb.Match
+	for _, hint := range breachHints {
+		sessionsToUpdates, ok := db.blobs[hint]
+		if !ok {
+			continue
+		}
+
+		for id, update := range sessionsToUpdates {
+			info, ok := db.sessions[id]
+			if !ok {
+				panic("session not found")
+			}
+
+			match := wtdb.Match{
+				ID:            id,
+				SeqNum:        update.SeqNum,
+				Hint:          hint,
+				EncryptedBlob: update.EncryptedBlob,
+				SessionInfo:   info,
+			}
+			matches = append(matches, match)
+		}
+	}
+
+	return matches, nil
+}
+
+// SetLookoutTip stores the provided epoch as the latest lookout tip epoch in
+// the tower database.
+func (db *TowerDB) SetLookoutTip(epoch *chainntnfs.BlockEpoch) error {
+	db.lastEpoch = epoch
+	return nil
+}
+
+// GetLookoutTip retrieves the current lookout tip block epoch from the tower
+// database.
+func (db *TowerDB) GetLookoutTip() (*chainntnfs.BlockEpoch, error) {
+	db.mu.Lock()
+	defer db.mu.Unlock()
+
+	return db.lastEpoch, nil
+}