fix(connectivity_plus): use Windows list manager events (#3829)

Author: edde746

packages/connectivity_plus/connectivity_plus/windows/connectivity_plus_plugin.cpp

@@ -10,7 +10,9 @@
 #include <flutter/plugin_registrar_windows.h>
 #include <flutter/standard_method_codec.h>
 
+#include <algorithm>
 #include <functional>
+#include <map>
 #include <memory>
 
 namespace {
@@ -56,10 +58,24 @@ class ConnectivityStreamHandler : public FlStreamHandler {
   OnCancelInternal(const flutter::EncodableValue *arguments) override;
 
 private:
+  bool TryStartListen();
+  void ScheduleStartListenRetry();
+  void CancelStartListenRetry();
+  static void CALLBACK RetryTimerProc(HWND hwnd, UINT message, UINT_PTR id,
+                                      DWORD time);
+
+  // Thread-affine (platform thread), like the stream handler itself.
+  static std::map<UINT_PTR, ConnectivityStreamHandler *> retry_handlers_;
+
   std::shared_ptr<NetworkManager> manager;
   std::unique_ptr<FlEventSink> sink;
+  UINT_PTR retry_timer_id_ = 0;
+  int retry_attempts_ = 0;
 };
 
+std::map<UINT_PTR, ConnectivityStreamHandler *>
+    ConnectivityStreamHandler::retry_handlers_;
+
 ConnectivityPlusWindowsPlugin::ConnectivityPlusWindowsPlugin() {
   manager = std::make_shared<NetworkManager>();
   manager->Init();
@@ -146,25 +162,92 @@ ConnectivityStreamHandler::ConnectivityStreamHandler(
     std::shared_ptr<NetworkManager> manager)
     : manager(manager) {}
 
-ConnectivityStreamHandler::~ConnectivityStreamHandler() {}
+ConnectivityStreamHandler::~ConnectivityStreamHandler() {
+  CancelStartListenRetry();
+}
 
 void ConnectivityStreamHandler::AddConnectivityEvent() {
   sink->Success(EncodeConnectivityTypes(manager->GetConnectivityTypes()));
 }
 
+bool ConnectivityStreamHandler::TryStartListen() {
+  auto callback =
+      std::bind(&ConnectivityStreamHandler::AddConnectivityEvent, this);
+  return manager->StartListen(callback);
+}
+
+void ConnectivityStreamHandler::ScheduleStartListenRetry() {
+  // 100ms, 200ms, 400ms, ... — enough to escape whatever input-synchronous
+  // window the platform thread was inside.
+  UINT delay = 100u << (std::min)(retry_attempts_, 4);
+  retry_timer_id_ = SetTimer(nullptr, 0, delay, RetryTimerProc);
+  if (retry_timer_id_ != 0) {
+    retry_handlers_[retry_timer_id_] = this;
+  }
+}
+
+void ConnectivityStreamHandler::CancelStartListenRetry() {
+  if (retry_timer_id_ != 0) {
+    KillTimer(nullptr, retry_timer_id_);
+    retry_handlers_.erase(retry_timer_id_);
+    retry_timer_id_ = 0;
+  }
+}
+
+void CALLBACK ConnectivityStreamHandler::RetryTimerProc(HWND hwnd,
+                                                        UINT message,
+                                                        UINT_PTR id,
+                                                        DWORD time) {
+  KillTimer(hwnd, id);
+  auto it = retry_handlers_.find(id);
+  if (it == retry_handlers_.end()) {
+    return;
+  }
+  ConnectivityStreamHandler *self = it->second;
+  retry_handlers_.erase(it);
+  self->retry_timer_id_ = 0;
+
+  if (!self->sink) {
+    return; // Cancelled while the retry was pending.
+  }
+
+  if (self->TryStartListen()) {
+    self->AddConnectivityEvent();
+    return;
+  }
+
+  if (self->manager->GetError() == RPC_E_CANTCALLOUT_ININPUTSYNCCALL &&
+      ++self->retry_attempts_ < 5) {
+    self->ScheduleStartListenRetry();
+    return;
+  }
+
+  // Persistent failure: report through the sink, where Dart-side stream
+  // onError handlers can observe it (unlike an OnListen error, which the
+  // framework can only surface as an uncatchable FlutterError).
+  self->sink->Error(std::to_string(self->manager->GetError()),
+                    "NetworkManager::StartListen", nullptr);
+}
+
 std::unique_ptr<FlStreamHandlerError>
 ConnectivityStreamHandler::OnListenInternal(
     const flutter::EncodableValue *arguments,
     std::unique_ptr<FlEventSink> &&events) {
   sink = std::move(events);
 
-  auto callback =
-      std::bind(&ConnectivityStreamHandler::AddConnectivityEvent, this);
-
-  if (!manager->StartListen(callback)) {
-    return std::make_unique<FlStreamHandlerError>(
-        std::to_string(manager->GetError()), "NetworkManager::StartListen",
-        nullptr);
+  if (!TryStartListen()) {
+    if (manager->GetError() == RPC_E_CANTCALLOUT_ININPUTSYNCCALL) {
+      // The platform thread is inside an input-synchronous call (e.g. a
+      // SendMessage-driven window callback), where COM rejects the outgoing
+      // Advise. The subscription itself is fine — retry once the message
+      // loop spins, and still emit the initial snapshot below.
+      retry_attempts_ = 0;
+      ScheduleStartListenRetry();
+    } else {
+      return std::make_unique<FlStreamHandlerError>(
+          std::to_string(manager->GetError()), "NetworkManager::StartListen",
+          nullptr);
+    }
   }
 
   AddConnectivityEvent();
@@ -174,6 +257,7 @@ ConnectivityStreamHandler::OnListenInternal(
 std::unique_ptr<FlStreamHandlerError>
 ConnectivityStreamHandler::OnCancelInternal(
     const flutter::EncodableValue *arguments) {
+  CancelStartListenRetry();
   manager->StopListen();
   sink.reset();
   return nullptr;

packages/connectivity_plus/connectivity_plus/windows/include/connectivity_plus/network_manager.h

@@ -45,6 +45,7 @@ class NetworkManager {
   IConnectionPointContainer *pCPContainer = NULL;
   IConnectionPoint *pConnectPoint = NULL;
   NetworkListener *pListener = NULL;
+  HRESULT lastError = S_OK;
 };
 
 #endif // NETWORK_MANAGER_H

packages/connectivity_plus/connectivity_plus/windows/network_manager.cpp

@@ -18,22 +18,26 @@
 #include <cassert>
 #include <set>
 
-class NetworkListener final : public INetworkEvents {
+class NetworkListener final : public INetworkListManagerEvents {
 public:
   NetworkListener(NetworkCallback pCb) : pCallback(pCb) {}
 
   HRESULT STDMETHODCALLTYPE QueryInterface(REFIID riid, void **ppvObject) {
-    AddRef();
+    if (!ppvObject) {
+      return E_POINTER;
+    }
 
-    HRESULT hr = S_OK;
     if (IsEqualIID(riid, IID_IUnknown)) {
-      *ppvObject = (IUnknown *)this;
-    } else if (IsEqualIID(riid, IID_INetworkEvents)) {
-      *ppvObject = (INetworkEvents *)this;
+      *ppvObject = static_cast<IUnknown *>(this);
+    } else if (IsEqualIID(riid, IID_INetworkListManagerEvents)) {
+      *ppvObject = static_cast<INetworkListManagerEvents *>(this);
     } else {
-      hr = E_NOINTERFACE;
+      *ppvObject = nullptr;
+      return E_NOINTERFACE;
     }
-    return hr;
+
+    AddRef();
+    return S_OK;
   }
 
   ULONG STDMETHODCALLTYPE AddRef() { return InterlockedIncrement(&lRef); }
@@ -46,24 +50,11 @@ class NetworkListener final : public INetworkEvents {
     return lAddend;
   }
 
-  HRESULT STDMETHODCALLTYPE NetworkAdded(GUID networkId) { return S_OK; }
-
-  HRESULT STDMETHODCALLTYPE
-  NetworkConnectivityChanged(GUID networkId, NLM_CONNECTIVITY newConnectivity) {
+  HRESULT STDMETHODCALLTYPE ConnectivityChanged(NLM_CONNECTIVITY) {
     Callback();
     return S_OK;
   }
 
-  HRESULT STDMETHODCALLTYPE NetworkDeleted(GUID networkId) { return S_OK; }
-
-  HRESULT STDMETHODCALLTYPE
-  NetworkPropertyChanged(GUID networkId, NLM_NETWORK_PROPERTY_CHANGE flags) {
-    if (flags & NLM_NETWORK_PROPERTY_CHANGE_CONNECTION) {
-      Callback();
-    }
-    return S_OK;
-  }
-
   void Callback() {
     assert(pCallback);
     pCallback();
@@ -209,14 +200,25 @@ std::set<ConnectivityType> NetworkManager::GetConnectivityTypes() const {
 }
 
 bool NetworkManager::StartListen(NetworkCallback pCallback) {
-  if (!pCallback || pListener) {
+  lastError = S_OK;
+  if (!pCallback) {
+    lastError = E_INVALIDARG;
+    return false;
+  }
+  if (pListener) {
+    lastError = HRESULT_FROM_WIN32(ERROR_ALREADY_EXISTS);
+    return false;
+  }
+  if (!pNetworkListManager) {
+    lastError = E_POINTER;
     return false;
   }
 
   HRESULT hr = pNetworkListManager->QueryInterface(
       IID_IConnectionPointContainer, (void **)&pCPContainer);
   if (SUCCEEDED(hr)) {
-    hr = pCPContainer->FindConnectionPoint(IID_INetworkEvents, &pConnectPoint);
+    hr = pCPContainer->FindConnectionPoint(IID_INetworkListManagerEvents,
+                                           &pConnectPoint);
     if (SUCCEEDED(hr)) {
       pListener = new NetworkListener(pCallback);
       hr = pConnectPoint->Advise((IUnknown *)pListener, &dwCookie);
@@ -225,12 +227,29 @@ bool NetworkManager::StartListen(NetworkCallback pCallback) {
       }
     }
   }
+
+  lastError = hr;
+  if (pListener) {
+    pListener->Release();
+    pListener = NULL;
+  }
+  if (pConnectPoint) {
+    pConnectPoint->Release();
+    pConnectPoint = NULL;
+  }
+  if (pCPContainer) {
+    pCPContainer->Release();
+    pCPContainer = NULL;
+  }
+  dwCookie = 0;
   return false;
 }
 
 void NetworkManager::StopListen() {
   if (pConnectPoint) {
-    pConnectPoint->Unadvise(dwCookie);
+    if (dwCookie != 0) {
+      pConnectPoint->Unadvise(dwCookie);
+    }
     pConnectPoint->Release();
     pConnectPoint = NULL;
     dwCookie = 0;
@@ -247,6 +266,6 @@ void NetworkManager::StopListen() {
   }
 }
 
-bool NetworkManager::HasError() const { return GetLastError() != 0; }
+bool NetworkManager::HasError() const { return FAILED(lastError); }
 
-int NetworkManager::GetError() const { return GetLastError(); }
+int NetworkManager::GetError() const { return static_cast<int>(lastError); }