Fix is_regular_file again (#1218)

src/AspNetCoreModuleV2/AspNetCore/AppOfflineApplication.cpp

@@ -57,5 +57,5 @@ HRESULT AppOfflineApplication::OnAppOfflineFound()
 
 bool AppOfflineApplication::ShouldBeStarted(IHttpApplication& pApplication)
 {
-    return is_regular_file(GetAppOfflineLocation(pApplication));
+    return FileExists(GetAppOfflineLocation(pApplication));
 }

src/AspNetCoreModuleV2/AspNetCore/PollingAppOfflineApplication.cpp

@@ -28,20 +28,12 @@ PollingAppOfflineApplication::CheckAppOffline()
         SRWExclusiveLock lock(m_statusLock);
         if (ulCurrentTime - m_ulLastCheckTime > c_appOfflineRefreshIntervalMS)
         {
-            try
+            m_fAppOfflineFound = FileExists(m_appOfflineLocation);
+            if(m_fAppOfflineFound)
             {
-                m_fAppOfflineFound = is_regular_file(m_appOfflineLocation);
+                LOG_IF_FAILED(OnAppOfflineFound());
-                if(m_fAppOfflineFound)
-                {
-                    LOG_IF_FAILED(OnAppOfflineFound());
-                }
-                m_ulLastCheckTime = ulCurrentTime;
-            }
-            catch (...)
-            {
-                // is_regular_file might throw in very rare cases
-                OBSERVE_CAUGHT_EXCEPTION();
             }
+            m_ulLastCheckTime = ulCurrentTime;
         }
     }
 
@@ -56,3 +48,9 @@ std::filesystem::path PollingAppOfflineApplication::GetAppOfflineLocation(IHttpA
 {
     return std::filesystem::path(pApplication.GetApplicationPhysicalPath()) / "app_offline.htm";
 }
+
+bool PollingAppOfflineApplication::FileExists(const std::filesystem::path& path)
+{
+    std::error_code ec;
+    return is_regular_file(path, ec) || ec.value() == ERROR_SHARING_VIOLATION;
+}

src/AspNetCoreModuleV2/AspNetCore/PollingAppOfflineApplication.h

@@ -32,7 +32,7 @@ public:
 protected:
     std::filesystem::path m_appOfflineLocation;
     static std::filesystem::path GetAppOfflineLocation(IHttpApplication& pApplication);
-
+    static bool FileExists(const std::filesystem::path& path);
 private:
     static const int c_appOfflineRefreshIntervalMS = 200;
     std::string m_strAppOfflineContent;