lib/model: Use factories for creating folders

GitHub-Pull-Request: https://github.com/syncthing/syncthing/pull/3029

lib/model/model.go

@@ -100,8 +100,11 @@ type Model struct {
 	pmut              sync.RWMutex // protects the above
 }
 
+type folderFactory func(*Model, config.FolderConfiguration, versioner.Versioner) service
+
 var (
-	symlinkWarning = stdsync.Once{}
+	symlinkWarning  = stdsync.Once{}
+	folderFactories = make(map[string]folderFactory, 0)
 )
 
 // NewModel creates and starts a new model. The model starts in read-only mode,
@@ -158,10 +161,8 @@ func (m *Model) StartDeadlockDetector(timeout time.Duration) {
 	deadlockDetect(m.pmut, timeout)
 }
 
-// StartFolderRW starts read/write processing on the current model. When in
-// read/write mode the model will attempt to keep in sync with the cluster by
-// pulling needed files from peer devices.
-func (m *Model) StartFolderRW(folder string) {
+// StartFolder constrcuts the folder service and starts it.
+func (m *Model) StartFolder(folder string) {
 	m.fmut.Lock()
 	cfg, ok := m.folderCfgs[folder]
 	if !ok {
@@ -172,37 +173,43 @@ func (m *Model) StartFolderRW(folder string) {
 	if ok {
 		panic("cannot start already running folder " + folder)
 	}
-	p := newRWFolder(m, cfg)
-	m.folderRunners[folder] = p
 
+	folderFactory, ok := folderFactories[cfg.Type]
+	if !ok {
+		panic("unknown folder type " + cfg.Type)
+	}
+
+	var ver versioner.Versioner
 	if len(cfg.Versioning.Type) > 0 {
-		factory, ok := versioner.Factories[cfg.Versioning.Type]
+		versionerFactory, ok := versioner.Factories[cfg.Versioning.Type]
 		if !ok {
 			l.Fatalf("Requested versioning type %q that does not exist", cfg.Versioning.Type)
 		}
 
-		versioner := factory(folder, cfg.Path(), cfg.Versioning.Params)
-		if service, ok := versioner.(suture.Service); ok {
+		ver = versionerFactory(folder, cfg.Path(), cfg.Versioning.Params)
+		if service, ok := ver.(suture.Service); ok {
 			// The versioner implements the suture.Service interface, so
 			// expects to be run in the background in addition to being called
 			// when files are going to be archived.
 			token := m.Add(service)
 			m.folderRunnerTokens[folder] = append(m.folderRunnerTokens[folder], token)
 		}
-		p.versioner = versioner
 	}
 
+	p := folderFactory(m, cfg, ver)
+	m.folderRunners[folder] = p
+
 	m.warnAboutOverwritingProtectedFiles(folder)
 
 	token := m.Add(p)
 	m.folderRunnerTokens[folder] = append(m.folderRunnerTokens[folder], token)
 	m.fmut.Unlock()
 
-	l.Infoln("Ready to synchronize", folder, "(read-write)")
+	l.Infoln("Ready to synchronize", folder, fmt.Sprintf("(%s)", cfg.Type))
 }
 
 func (m *Model) warnAboutOverwritingProtectedFiles(folder string) {
-	if m.folderCfgs[folder].ReadOnly {
+	if m.folderCfgs[folder].Type == config.FolderTypeReadOnly {
 		return
 	}
 
@@ -229,30 +236,6 @@ func (m *Model) warnAboutOverwritingProtectedFiles(folder string) {
 	}
 }
 
-// StartFolderRO starts read only processing on the current model. When in
-// read only mode the model will announce files to the cluster but not pull in
-// any external changes.
-func (m *Model) StartFolderRO(folder string) {
-	m.fmut.Lock()
-	cfg, ok := m.folderCfgs[folder]
-	if !ok {
-		panic("cannot start nonexistent folder " + folder)
-	}
-
-	_, ok = m.folderRunners[folder]
-	if ok {
-		panic("cannot start already running folder " + folder)
-	}
-	s := newROFolder(m, cfg)
-	m.folderRunners[folder] = s
-
-	token := m.Add(s)
-	m.folderRunnerTokens[folder] = append(m.folderRunnerTokens[folder], token)
-	m.fmut.Unlock()
-
-	l.Infoln("Ready to synchronize", folder, "(read only; no external updates accepted)")
-}
-
 func (m *Model) RemoveFolder(folder string) {
 	m.fmut.Lock()
 	m.pmut.Lock()
@@ -1093,7 +1076,7 @@ func (m *Model) DownloadProgress(device protocol.DeviceID, folder string, update
 	cfg, ok := m.folderCfgs[folder]
 	m.fmut.RUnlock()
 
-	if !ok || cfg.ReadOnly || cfg.DisableTempIndexes {
+	if !ok || cfg.Type == config.FolderTypeReadOnly || cfg.DisableTempIndexes {
 		return
 	}
 
@@ -1606,7 +1589,7 @@ func (m *Model) generateClusterConfig(device protocol.DeviceID) protocol.Cluster
 			Label: folderCfg.Label,
 		}
 		var flags uint32
-		if folderCfg.ReadOnly {
+		if folderCfg.Type == config.FolderTypeReadOnly {
 			flags |= protocol.FlagFolderReadOnly
 		}
 		if folderCfg.IgnorePerms {
@@ -1874,7 +1857,7 @@ func (m *Model) CheckFolderHealth(id string) error {
 		case !folder.HasMarker():
 			err = errors.New("folder marker missing")
 
-		case !folder.ReadOnly:
+		case folder.Type != config.FolderTypeReadOnly:
 			// Check for free space, if it isn't a master folder. We aren't
 			// going to change the contents of master folders, so we don't
 			// care about the amount of free space there.
@@ -1951,11 +1934,7 @@ func (m *Model) CommitConfiguration(from, to config.Configuration) bool {
 			// A folder was added.
 			l.Debugln(m, "adding folder", folderID)
 			m.AddFolder(cfg)
-			if cfg.ReadOnly {
-				m.StartFolderRO(folderID)
-			} else {
-				m.StartFolderRW(folderID)
-			}
+			m.StartFolder(folderID)
 
 			// Drop connections to all devices that can now share the new
 			// folder.