From 6098d4af9d4e3a639c6ad7f81059e16274fd6c89 Mon Sep 17 00:00:00 2001
From: Juliusz Chroboczek <jch@irif.fr>
Date: Thu, 14 Jan 2021 03:56:37 +0100
Subject: [PATCH] Implement autolock.

---
 README                   |  2 ++
 diskwriter/diskwriter.go |  4 +++
 group/client.go          |  1 +
 group/group.go           | 55 +++++++++++++++++++++++++++-------------
 rtpconn/webclient.go     |  4 +++
 5 files changed, 48 insertions(+), 18 deletions(-)

diff --git a/README b/README
index 01b0aa3..11bae08 100644
--- a/README
+++ b/README
@@ -235,6 +235,8 @@ the group.
  - `allow-anonymous`: if true, then users may connect with an empty username;
  - `allow-subgroups`: if true, then subgroups of the form `group/subgroup`
    are automatically created when first accessed;
+ - `autolock`: if true, the group will start locked and become locked
+   whenever there are no clients with operator privileges;
  - `redirect`: if set, then attempts to join the group will be redirected
    to the given URL; most other fields are ignored in this case;
  - `codecs`: this is a list of codecs allowed in this group.  The default
diff --git a/diskwriter/diskwriter.go b/diskwriter/diskwriter.go
index 725d737..52db542 100644
--- a/diskwriter/diskwriter.go
+++ b/diskwriter/diskwriter.go
@@ -67,6 +67,10 @@ func (client *Client) SetPermissions(perms group.ClientPermissions) {
 	return
 }
 
+func (client *Client) Permissions() group.ClientPermissions {
+	return group.ClientPermissions{}
+}
+
 func (client *Client) PushClient(id, username string, add bool) error {
 	return nil
 }
diff --git a/group/client.go b/group/client.go
index 67212a3..db51b87 100644
--- a/group/client.go
+++ b/group/client.go
@@ -96,6 +96,7 @@ type Client interface {
 	Group() *Group
 	Id() string
 	Challengeable
+	Permissions() ClientPermissions
 	SetPermissions(ClientPermissions)
 	OverridePermissions(*Group) bool
 	PushConn(g *Group, id string, conn conn.Up, tracks []conn.UpTrack) error
diff --git a/group/group.go b/group/group.go
index 16fa8ea..413e2fa 100644
--- a/group/group.go
+++ b/group/group.go
@@ -293,6 +293,7 @@ func Add(name string, desc *description) (*Group, error) {
 			timestamp:   time.Now(),
 			api:         APIFromNames(desc.Codecs),
 		}
+		autolock(g, g.getClientsUnlocked(nil))
 		groups.groups[name] = g
 		return g, nil
 	}
@@ -302,27 +303,24 @@ func Add(name string, desc *description) (*Group, error) {
 
 	if desc != nil {
 		g.description = desc
-		g.api = APIFromNames(desc.Codecs)
+	} else if time.Since(g.description.loadTime) < 5*time.Second {
+		return g, nil
+	} else if !descriptionChanged(name, g.description) {
+		g.description.loadTime = time.Now()
 		return g, nil
 	}
 
-	if time.Since(g.description.loadTime) > 5*time.Second {
-		if descriptionChanged(name, g.description) {
-			desc, err := GetDescription(name)
-			if err != nil {
-				if !os.IsNotExist(err) {
-					log.Printf("Reading group %v: %v",
-						name, err)
-				}
-				deleteUnlocked(g)
-				return nil, err
-			}
-			g.description = desc
-			g.api = APIFromNames(desc.Codecs)
-		} else {
-			g.description.loadTime = time.Now()
+	desc, err = GetDescription(name)
+	if err != nil {
+		if !os.IsNotExist(err) {
+			log.Printf("Reading group %v: %v", name, err)
 		}
+		deleteUnlocked(g)
+		return nil, err
 	}
+	g.description = desc
+	g.api = APIFromNames(desc.Codecs)
+	autolock(g, g.getClientsUnlocked(nil))
 
 	return g, nil
 }
@@ -451,7 +449,7 @@ func AddClient(group string, c Client) (*Group, error) {
 		if !perms.Op && g.locked != nil {
 			m := *g.locked
 			if m == "" {
-				m = "group is locked"
+				m = "this group is locked"
 			}
 			return nil, UserError(m)
 		}
@@ -483,6 +481,22 @@ func AddClient(group string, c Client) (*Group, error) {
 	return g, nil
 }
 
+// called locked
+func autolock(g *Group, clients []Client) {
+	if g.locked == nil && g.description.Autolock {
+		lock := true
+		for _, c := range clients {
+			if c.Permissions().Op {
+				lock = false
+			}
+		}
+		if lock {
+			m := "this group is locked"
+			g.locked = &m
+		}
+	}
+}
+
 func DelClient(c Client) {
 	g := c.Group()
 	if g == nil {
@@ -498,11 +512,15 @@ func DelClient(c Client) {
 	delete(g.clients, c.Id())
 	g.timestamp = time.Now()
 
+	clients := g.getClientsUnlocked(nil)
+
 	go func(clients []Client) {
 		for _, cc := range clients {
 			cc.PushClient(c.Id(), c.Username(), false)
 		}
-	}(g.getClientsUnlocked(nil))
+	}(clients)
+
+	autolock(g, clients)
 }
 
 func (g *Group) GetClients(except Client) []Client {
@@ -668,6 +686,7 @@ type description struct {
 	AllowAnonymous bool                `json:"allow-anonymous,omitempty"`
 	AllowRecording bool                `json:"allow-recording,omitempty"`
 	AllowSubgroups bool                `json:"allow-subgroups,omitempty"`
+	Autolock       bool                `json:"autolock,omitempty"`
 	Op             []ClientCredentials `json:"op,omitempty"`
 	Presenter      []ClientCredentials `json:"presenter,omitempty"`
 	Other          []ClientCredentials `json:"other,omitempty"`
diff --git a/rtpconn/webclient.go b/rtpconn/webclient.go
index 7842772..fada36c 100644
--- a/rtpconn/webclient.go
+++ b/rtpconn/webclient.go
@@ -93,6 +93,10 @@ func (c *webClient) Challenge(group string, creds group.ClientCredentials) bool
 	return m
 }
 
+func (c *webClient) Permissions() group.ClientPermissions {
+	return c.permissions
+}
+
 func (c *webClient) SetPermissions(perms group.ClientPermissions) {
 	c.permissions = perms
 }