From b85302f928965da320c5f9d50f0547010e132ec5 Mon Sep 17 00:00:00 2001
From: levlam <levlam@telegram.org>
Date: Mon, 23 Dec 2019 18:37:11 +0300
Subject: [PATCH] Add direct cache for linked channels.

GitOrigin-RevId: 1d994bd0aef96c379312a4be776b7a107cd175da
---
 td/telegram/ContactsManager.cpp | 40 ++++++++++++++++++++++++++++++---
 td/telegram/ContactsManager.h   |  5 +++++
 2 files changed, 42 insertions(+), 3 deletions(-)

diff --git a/td/telegram/ContactsManager.cpp b/td/telegram/ContactsManager.cpp
index 85a6ead0d..6b164bb23 100644
--- a/td/telegram/ContactsManager.cpp
+++ b/td/telegram/ContactsManager.cpp
@@ -3722,9 +3722,9 @@ bool ContactsManager::have_input_peer_channel(const Channel *c, ChannelId channe
       return true;
     }
     if (!from_linked && c->has_linked_channel) {
-      auto channel_full = get_channel_full(channel_id);
-      if (channel_full == nullptr || have_input_peer_channel(get_channel(channel_full->linked_channel_id),
-                                                             channel_full->linked_channel_id, access_rights, true)) {
+      auto linked_channel_id = get_linked_channel_id(channel_id);
+      if (linked_channel_id.is_valid() &&
+          have_input_peer_channel(get_channel(linked_channel_id), linked_channel_id, access_rights, true)) {
         return true;
       }
     }
@@ -9866,8 +9866,42 @@ void ContactsManager::on_update_channel_full_invite_link(
   }
 }
 
+void ContactsManager::remove_linked_channel_id(ChannelId channel_id) {
+  if (!channel_id.is_valid()) {
+    return;
+  }
+
+  auto it = linked_channel_ids_.find(channel_id);
+  if (it != linked_channel_ids_.end()) {
+    auto channel_id = it->second;
+    linked_channel_ids_.erase(it);
+    linked_channel_ids_.erase(channel_id);
+  }
+}
+
+ChannelId ContactsManager::get_linked_channel_id(ChannelId channel_id) const {
+  auto channel_full = get_channel_full(channel_id);
+  if (channel_full != nullptr) {
+    return channel_full->linked_channel_id;
+  }
+
+  auto it = linked_channel_ids_.find(channel_id);
+  if (it != linked_channel_ids_.end()) {
+    return it->second;
+  }
+
+  return ChannelId();
+}
+
 void ContactsManager::on_update_channel_full_linked_channel_id(ChannelFull *channel_full, ChannelId channel_id,
                                                                ChannelId linked_channel_id) {
+  remove_linked_channel_id(channel_id);
+  remove_linked_channel_id(linked_channel_id);
+  if (channel_id.is_valid() && linked_channel_id.is_valid()) {
+    linked_channel_ids_[channel_id] = linked_channel_id;
+    linked_channel_ids_[linked_channel_id] = channel_id;
+  }
+
   if (channel_full != nullptr && channel_full->linked_channel_id != linked_channel_id) {
     if (channel_full->linked_channel_id.is_valid()) {
       // remove link from a previously linked channel_full
diff --git a/td/telegram/ContactsManager.h b/td/telegram/ContactsManager.h
index 7f742ef81..ca037bd3d 100644
--- a/td/telegram/ContactsManager.h
+++ b/td/telegram/ContactsManager.h
@@ -1102,6 +1102,9 @@ class ContactsManager : public Actor {
   void on_update_channel_full_bot_user_ids(ChannelFull *channel_full, ChannelId channel_id,
                                            vector<UserId> &&bot_user_ids);
 
+  void remove_linked_channel_id(ChannelId channel_id);
+  ChannelId get_linked_channel_id(ChannelId channel_id) const;
+
   static bool speculative_add_count(int32 &count, int32 new_count);
 
   void speculative_add_channel_participants(ChannelId channel_id, int32 new_participant_count, bool by_me);
@@ -1420,6 +1423,8 @@ class ContactsManager : public Actor {
   vector<DialogNearby> users_nearby_;
   vector<DialogNearby> channels_nearby_;
 
+  std::unordered_map<ChannelId, ChannelId, ChannelIdHash> linked_channel_ids_;
+
   std::unordered_set<UserId, UserIdHash> restricted_user_ids_;
   std::unordered_set<ChannelId, ChannelIdHash> restricted_channel_ids_;