From 5ae556499bb7f2ff1cd196b69025f6f623c8d82d Mon Sep 17 00:00:00 2001
From: Guogang Li <guogang@google.com>
Date: Wed, 14 Jun 2023 08:52:00 -0700
Subject: [PATCH] Fixed the deadlock issue in hotspot

PiperOrigin-RevId: 540283852
---
 .../implementation/windows/wifi_direct_medium.cc | 16 ++++++++--------
 .../windows/wifi_hotspot_medium.cc               | 15 ++++++++-------
 .../windows/wifi_hotspot_server_socket.cc        |  8 ++++----
 3 files changed, 20 insertions(+), 19 deletions(-)

diff --git a/internal/platform/implementation/windows/wifi_direct_medium.cc b/internal/platform/implementation/windows/wifi_direct_medium.cc
index c27595d0..7ced0f48 100644
--- a/internal/platform/implementation/windows/wifi_direct_medium.cc
+++ b/internal/platform/implementation/windows/wifi_direct_medium.cc
@@ -175,16 +175,16 @@ std::unique_ptr<api::WifiDirectServerSocket> WifiDirectMedium::ListenForService(
   auto server_socket = std::make_unique<WifiDirectServerSocket>(port);
   server_socket_ptr_ = server_socket.get();
 
-  server_socket->SetCloseNotifier([this]() {
-    absl::MutexLock lock(&mutex_);
-    NEARBY_LOGS(INFO) << "server socket was closed on port "
-                      << server_socket_ptr_->GetPort();
-    medium_status_ &= (~kMediumStatusAccepting);
-    server_socket_ptr_ = nullptr;
-  });
-
   if (server_socket->listen()) {
     medium_status_ |= kMediumStatusAccepting;
+    server_socket->SetCloseNotifier([this]() {
+      absl::MutexLock lock(&mutex_);
+      NEARBY_LOGS(INFO) << "server socket was closed on port "
+                        << server_socket_ptr_->GetPort();
+      medium_status_ &= (~kMediumStatusAccepting);
+      server_socket_ptr_ = nullptr;
+    });
+
     NEARBY_LOGS(INFO) << "started to listen serive on port "
                       << server_socket_ptr_->GetPort();
     return server_socket;
diff --git a/internal/platform/implementation/windows/wifi_hotspot_medium.cc b/internal/platform/implementation/windows/wifi_hotspot_medium.cc
index 8a3532f7..80c2fe3e 100644
--- a/internal/platform/implementation/windows/wifi_hotspot_medium.cc
+++ b/internal/platform/implementation/windows/wifi_hotspot_medium.cc
@@ -192,15 +192,16 @@ WifiHotspotMedium::ListenForService(int port) {
   auto server_socket = std::make_unique<WifiHotspotServerSocket>(port);
   server_socket_ptr_ = server_socket.get();
 
-  server_socket->SetCloseNotifier([this]() {
-    absl::MutexLock lock(&mutex_);
-    NEARBY_LOGS(INFO) << "Server socket was closed.";
-    medium_status_ &= (~kMediumStatusAccepting);
-    server_socket_ptr_ = nullptr;
-  });
-
   if (server_socket->listen()) {
     medium_status_ |= kMediumStatusAccepting;
+
+    // Setup close notifier after listen started.
+    server_socket->SetCloseNotifier([this]() {
+      absl::MutexLock lock(&mutex_);
+      NEARBY_LOGS(INFO) << "Server socket was closed.";
+      medium_status_ &= (~kMediumStatusAccepting);
+      server_socket_ptr_ = nullptr;
+    });
     NEARBY_LOGS(INFO) << "Started to listen serive on port "
                       << server_socket_ptr_->GetPort();
     return server_socket;
diff --git a/internal/platform/implementation/windows/wifi_hotspot_server_socket.cc b/internal/platform/implementation/windows/wifi_hotspot_server_socket.cc
index 3b742a2f..4a49ed82 100644
--- a/internal/platform/implementation/windows/wifi_hotspot_server_socket.cc
+++ b/internal/platform/implementation/windows/wifi_hotspot_server_socket.cc
@@ -123,6 +123,10 @@ Exception WifiHotspotServerSocket::Close() {
     absl::MutexLock lock(&mutex_);
     NEARBY_LOGS(INFO) << __func__ << ": Close is called.";
 
+    if (closed_) {
+      return {Exception::kSuccess};
+    }
+
     if (NearbyFlags::GetInstance().GetBoolFlag(
             platform::config_package_nearby::nearby_platform_feature::
                 kEnableHotspotWin32Socket)) {
@@ -154,10 +158,6 @@ Exception WifiHotspotServerSocket::Close() {
       }
     }
 
-    if (closed_) {
-      return {Exception::kSuccess};
-    }
-
     closed_ = true;
     cond_.SignalAll();
     if (close_notifier_ != nullptr) {