From 862cd8a0d74a8c38ac21bfe44788cc6671046ef0 Mon Sep 17 00:00:00 2001
From: Tulir Asokan <tulir@maunium.net>
Date: Thu, 29 Sep 2022 14:39:58 +0300
Subject: [PATCH] Add option to sync group members in parallel

---
 config/bridge.go    |  1 +
 config/upgrade.go   |  1 +
 example-config.yaml |  2 ++
 portal.go           | 38 +++++++++++++++++++++++++++++---------
 4 files changed, 33 insertions(+), 9 deletions(-)

diff --git a/config/bridge.go b/config/bridge.go
index 5828ee7..bb4fb86 100644
--- a/config/bridge.go
+++ b/config/bridge.go
@@ -94,6 +94,7 @@ type BridgeConfig struct {
 	LoginSharedSecretMap       map[string]string `yaml:"login_shared_secret_map"`
 
 	PrivateChatPortalMeta bool   `yaml:"private_chat_portal_meta"`
+	ParallelMemberSync    bool   `yaml:"parallel_member_sync"`
 	BridgeNotices         bool   `yaml:"bridge_notices"`
 	ResendBridgeInfo      bool   `yaml:"resend_bridge_info"`
 	MuteBridging          bool   `yaml:"mute_bridging"`
diff --git a/config/upgrade.go b/config/upgrade.go
index 562c8a1..2d83b58 100644
--- a/config/upgrade.go
+++ b/config/upgrade.go
@@ -73,6 +73,7 @@ func DoUpgrade(helper *up.Helper) {
 		helper.Copy(up.Map, "bridge", "login_shared_secret_map")
 	}
 	helper.Copy(up.Bool, "bridge", "private_chat_portal_meta")
+	helper.Copy(up.Bool, "bridge", "parallel_member_sync")
 	helper.Copy(up.Bool, "bridge", "bridge_notices")
 	helper.Copy(up.Bool, "bridge", "resend_bridge_info")
 	helper.Copy(up.Bool, "bridge", "mute_bridging")
diff --git a/example-config.yaml b/example-config.yaml
index 864b8c9..1b662f6 100644
--- a/example-config.yaml
+++ b/example-config.yaml
@@ -232,6 +232,8 @@ bridge:
         example.com: foobar
     # Should the bridge explicitly set the avatar and room name for private chat portal rooms?
     private_chat_portal_meta: false
+    # Should group members be synced in parallel? This makes member sync faster
+    parallel_member_sync: false
     # Should Matrix m.notice-type messages be bridged?
     bridge_notices: true
     # Set this to true to tell the bridge to re-send m.bridge events to all rooms on the next run.
diff --git a/portal.go b/portal.go
index 787ef60..4ae4361 100644
--- a/portal.go
+++ b/portal.go
@@ -32,6 +32,7 @@ import (
 	"math"
 	"mime"
 	"net/http"
+	"runtime/debug"
 	"strconv"
 	"strings"
 	"sync"
@@ -898,6 +899,25 @@ func (portal *Portal) kickExtraUsers(participantMap map[types.JID]bool) {
 //	portal.kickExtraUsers(participantMap)
 //}
 
+func (portal *Portal) syncParticipant(source *User, participant types.GroupParticipant, puppet *Puppet, user *User, wg *sync.WaitGroup) {
+	defer func() {
+		wg.Done()
+		if err := recover(); err != nil {
+			portal.log.Errorfln("Syncing participant %s panicked: %v\n%s", participant.JID, err, debug.Stack())
+		}
+	}()
+	puppet.SyncContact(source, true, false, "group participant")
+	if user != nil && user != source {
+		portal.ensureUserInvited(user)
+	}
+	if user == nil || !puppet.IntentFor(portal).IsCustomPuppet {
+		err := puppet.IntentFor(portal).EnsureJoined(portal.MXID)
+		if err != nil {
+			portal.log.Warnfln("Failed to make puppet of %s join %s: %v", participant.JID, portal.MXID, err)
+		}
+	}
+}
+
 func (portal *Portal) SyncParticipants(source *User, metadata *types.GroupInfo) {
 	changed := false
 	levels, err := portal.MainIntent().PowerLevels(portal.MXID)
@@ -906,20 +926,18 @@ func (portal *Portal) SyncParticipants(source *User, metadata *types.GroupInfo)
 		changed = true
 	}
 	changed = portal.applyPowerLevelFixes(levels) || changed
+	var wg sync.WaitGroup
+	wg.Add(len(metadata.Participants))
 	participantMap := make(map[types.JID]bool)
 	for _, participant := range metadata.Participants {
+		portal.log.Debugfln("Syncing participant %s (admin: %t)", participant.JID, participant.IsAdmin)
 		participantMap[participant.JID] = true
 		puppet := portal.bridge.GetPuppetByJID(participant.JID)
-		puppet.SyncContact(source, true, false, "group participant")
 		user := portal.bridge.GetUserByJID(participant.JID)
-		if user != nil && user != source {
-			portal.ensureUserInvited(user)
-		}
-		if user == nil || !puppet.IntentFor(portal).IsCustomPuppet {
-			err = puppet.IntentFor(portal).EnsureJoined(portal.MXID)
-			if err != nil {
-				portal.log.Warnfln("Failed to make puppet of %s join %s: %v", participant.JID, portal.MXID, err)
-			}
+		if portal.bridge.Config.Bridge.ParallelMemberSync {
+			go portal.syncParticipant(source, participant, puppet, user, &wg)
+		} else {
+			portal.syncParticipant(source, participant, puppet, user, &wg)
 		}
 
 		expectedLevel := 0
@@ -940,6 +958,8 @@ func (portal *Portal) SyncParticipants(source *User, metadata *types.GroupInfo)
 		}
 	}
 	portal.kickExtraUsers(participantMap)
+	wg.Wait()
+	portal.log.Debugln("Participant sync completed")
 }
 
 func reuploadAvatar(intent *appservice.IntentAPI, url string) (id.ContentURI, error) {