From 27c1452fae386801eb8ad4c123a20e5d97591979 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Niels=20M=C3=B6ller?= <nisse@webrtc.org>
Date: Mon, 7 Feb 2022 16:44:21 +0100
Subject: [PATCH] Refactor BasicNetworkManager to use TQ methods and
 PendingTaskSafetyFlag.

Bug: webrtc:11988
Change-Id: I29a1023297510cc57fe81f02bc4ce06fcde614ea
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/251042
Reviewed-by: Jonas Oreland <jonaso@webrtc.org>
Reviewed-by: Tomas Gunnarsson <tommi@webrtc.org>
Commit-Queue: Niels Moller <nisse@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#35951}
---
 rtc_base/network.cc | 49 ++++++++++++++++++++++-----------------------
 rtc_base/network.h  |  6 ++----
 2 files changed, 26 insertions(+), 29 deletions(-)

diff --git a/rtc_base/network.cc b/rtc_base/network.cc
index 24c1993d0f..295d39c5d9 100644
--- a/rtc_base/network.cc
+++ b/rtc_base/network.cc
@@ -34,6 +34,7 @@
 #include "rtc_base/string_encode.h"
 #include "rtc_base/string_utils.h"
 #include "rtc_base/strings/string_builder.h"
+#include "rtc_base/task_utils/to_queued_task.h"
 #include "rtc_base/thread.h"
 #include "system_wrappers/include/field_trial.h"
 
@@ -48,9 +49,6 @@ constexpr uint8_t kVpns[2][6] = {
     {0x2, 0x50, 0x41, 0x0, 0x0, 0x1},
 };
 
-const uint32_t kUpdateNetworksMessage = 1;
-const uint32_t kSignalNetworksMessage = 2;
-
 // Fetch list of networks every two seconds.
 const int kNetworksUpdateIntervalMs = 2000;
 
@@ -528,7 +526,11 @@ BasicNetworkManager::BasicNetworkManager(
       bind_using_ifname_(
           !webrtc::field_trial::IsDisabled("WebRTC-BindUsingInterfaceName")) {}
 
-BasicNetworkManager::~BasicNetworkManager() {}
+BasicNetworkManager::~BasicNetworkManager() {
+  if (task_safety_flag_) {
+    task_safety_flag_->SetNotAlive();
+  }
+}
 
 void BasicNetworkManager::OnNetworksChanged() {
   RTC_DCHECK_RUN_ON(thread_);
@@ -897,9 +899,17 @@ void BasicNetworkManager::StartUpdating() {
     // we should trigger network signal immediately for the new clients
     // to start allocating ports.
     if (sent_first_update_)
-      thread_->Post(RTC_FROM_HERE, this, kSignalNetworksMessage);
+      thread_->PostTask(ToQueuedTask(task_safety_flag_, [this] {
+        RTC_DCHECK_RUN_ON(thread_);
+        SignalNetworksChanged();
+      }));
   } else {
-    thread_->Post(RTC_FROM_HERE, this, kUpdateNetworksMessage);
+    RTC_DCHECK(task_safety_flag_ == nullptr);
+    task_safety_flag_ = webrtc::PendingTaskSafetyFlag::Create();
+    thread_->PostTask(ToQueuedTask(task_safety_flag_, [this] {
+      RTC_DCHECK_RUN_ON(thread_);
+      UpdateNetworksContinually();
+    }));
     StartNetworkMonitor();
   }
   ++start_count_;
@@ -912,7 +922,8 @@ void BasicNetworkManager::StopUpdating() {
 
   --start_count_;
   if (!start_count_) {
-    thread_->Clear(this);
+    task_safety_flag_->SetNotAlive();
+    task_safety_flag_ = nullptr;
     sent_first_update_ = false;
     StopNetworkMonitor();
   }
@@ -956,22 +967,6 @@ void BasicNetworkManager::StopNetworkMonitor() {
   }
 }
 
-void BasicNetworkManager::OnMessage(Message* msg) {
-  RTC_DCHECK_RUN_ON(thread_);
-  switch (msg->message_id) {
-    case kUpdateNetworksMessage: {
-      UpdateNetworksContinually();
-      break;
-    }
-    case kSignalNetworksMessage: {
-      SignalNetworksChanged();
-      break;
-    }
-    default:
-      RTC_DCHECK_NOTREACHED();
-  }
-}
-
 IPAddress BasicNetworkManager::QueryDefaultLocalAddress(int family) const {
   RTC_DCHECK(family == AF_INET || family == AF_INET6);
 
@@ -1026,8 +1021,12 @@ void BasicNetworkManager::UpdateNetworksOnce() {
 
 void BasicNetworkManager::UpdateNetworksContinually() {
   UpdateNetworksOnce();
-  thread_->PostDelayed(RTC_FROM_HERE, kNetworksUpdateIntervalMs, this,
-                       kUpdateNetworksMessage);
+  thread_->PostDelayedTask(ToQueuedTask(task_safety_flag_,
+                                        [this] {
+                                          RTC_DCHECK_RUN_ON(thread_);
+                                          UpdateNetworksContinually();
+                                        }),
+                           kNetworksUpdateIntervalMs);
 }
 
 void BasicNetworkManager::DumpNetworks() {
diff --git a/rtc_base/network.h b/rtc_base/network.h
index 5a64c34cd4..83a2f7d272 100644
--- a/rtc_base/network.h
+++ b/rtc_base/network.h
@@ -23,11 +23,11 @@
 #include "api/sequence_checker.h"
 #include "rtc_base/ip_address.h"
 #include "rtc_base/mdns_responder_interface.h"
-#include "rtc_base/message_handler.h"
 #include "rtc_base/network_monitor.h"
 #include "rtc_base/network_monitor_factory.h"
 #include "rtc_base/socket_factory.h"
 #include "rtc_base/system/rtc_export.h"
+#include "rtc_base/task_utils/pending_task_safety_flag.h"
 #include "rtc_base/third_party/sigslot/sigslot.h"
 #include "rtc_base/thread_annotations.h"
 
@@ -251,7 +251,6 @@ class RTC_EXPORT NetworkManagerBase : public NetworkManager {
 // Basic implementation of the NetworkManager interface that gets list
 // of networks using OS APIs.
 class RTC_EXPORT BasicNetworkManager : public NetworkManagerBase,
-                                       public MessageHandlerAutoCleanup,
                                        public NetworkBinderInterface,
                                        public sigslot::has_slots<> {
  public:
@@ -271,8 +270,6 @@ class RTC_EXPORT BasicNetworkManager : public NetworkManagerBase,
 
   void DumpNetworks() override;
 
-  // MessageHandler interface.
-  void OnMessage(Message* msg) override;
   bool started() { return start_count_ > 0; }
 
   // Sets the network ignore list, which is empty by default. Any network on the
@@ -347,6 +344,7 @@ class RTC_EXPORT BasicNetworkManager : public NetworkManagerBase,
   bool bind_using_ifname_ RTC_GUARDED_BY(thread_) = false;
 
   std::vector<NetworkMask> vpn_;
+  rtc::scoped_refptr<webrtc::PendingTaskSafetyFlag> task_safety_flag_;
 };
 
 // Represents a Unix-type network interface, with a name and single address.