eventmanager: add metadata check

Signed-off-by: Nicola Murino <nicola.murino@gmail.com>

internal/common/common.go

@@ -143,9 +143,11 @@ var (
 	// Connections is the list of active connections
 	Connections ActiveConnections
 	// QuotaScans is the list of active quota scans
-	QuotaScans         ActiveScans
-	transfersChecker   TransfersChecker
-	supportedProtocols = []string{ProtocolSFTP, ProtocolSCP, ProtocolSSH, ProtocolFTP, ProtocolWebDAV,
+	QuotaScans ActiveScans
+	// ActiveMetadataChecks holds the active metadata checks
+	ActiveMetadataChecks MetadataChecks
+	transfersChecker     TransfersChecker
+	supportedProtocols   = []string{ProtocolSFTP, ProtocolSCP, ProtocolSSH, ProtocolFTP, ProtocolWebDAV,
 		ProtocolHTTP, ProtocolHTTPShare, ProtocolOIDC}
 	disconnHookProtocols = []string{ProtocolSFTP, ProtocolSCP, ProtocolSSH, ProtocolFTP}
 	// the map key is the protocol, for each protocol we can have multiple rate limiters
@@ -1158,7 +1160,7 @@ func (c *ConnectionStatus) GetTransfersAsString() string {
 	return result
 }
 
-// ActiveQuotaScan defines an active quota scan for a user home dir
+// ActiveQuotaScan defines an active quota scan for a user
 type ActiveQuotaScan struct {
 	// Username to which the quota scan refers
 	Username string `json:"username"`
@@ -1181,7 +1183,7 @@ type ActiveScans struct {
 	FolderScans []ActiveVirtualFolderQuotaScan
 }
 
-// GetUsersQuotaScans returns the active quota scans for users home directories
+// GetUsersQuotaScans returns the active users quota scans
 func (s *ActiveScans) GetUsersQuotaScans() []ActiveQuotaScan {
 	s.RLock()
 	defer s.RUnlock()
@@ -1271,3 +1273,65 @@ func (s *ActiveScans) RemoveVFolderQuotaScan(folderName string) bool {
 
 	return false
 }
+
+// MetadataCheck defines an active metadata check
+type MetadataCheck struct {
+	// Username to which the metadata check refers
+	Username string `json:"username"`
+	// check start time as unix timestamp in milliseconds
+	StartTime int64 `json:"start_time"`
+}
+
+// MetadataChecks holds the active metadata checks
+type MetadataChecks struct {
+	sync.RWMutex
+	checks []MetadataCheck
+}
+
+// Get returns the active metadata checks
+func (c *MetadataChecks) Get() []MetadataCheck {
+	c.RLock()
+	defer c.RUnlock()
+
+	checks := make([]MetadataCheck, len(c.checks))
+	copy(checks, c.checks)
+
+	return checks
+}
+
+// Add adds a user to the ones with active metadata checks.
+// Return false if a metadata check is already active for the specified user
+func (c *MetadataChecks) Add(username string) bool {
+	c.Lock()
+	defer c.Unlock()
+
+	for idx := range c.checks {
+		if c.checks[idx].Username == username {
+			return false
+		}
+	}
+
+	c.checks = append(c.checks, MetadataCheck{
+		Username:  username,
+		StartTime: util.GetTimeAsMsSinceEpoch(time.Now()),
+	})
+
+	return true
+}
+
+// Remove removes a user from the ones with active metadata checks
+func (c *MetadataChecks) Remove(username string) bool {
+	c.Lock()
+	defer c.Unlock()
+
+	for idx := range c.checks {
+		if c.checks[idx].Username == username {
+			lastIdx := len(c.checks) - 1
+			c.checks[idx] = c.checks[lastIdx]
+			c.checks = c.checks[:lastIdx]
+			return true
+		}
+	}
+
+	return false
+}