win32: DeviceLister: don't use wchar_t string if they are NULL

src/filesystem/win32/DeviceLister.cpp

@@ -74,8 +74,13 @@ std::vector<CommonDeviceLister::Device> DeviceLister::networkDevices() const
             ss << "WNetEnumResource error: #" << GetLastError();
             throw fs::errors::DeviceListing{ ss.str() };
         }
-        std::string mountpoint = charset::FromWide( netResources->lpLocalName ).get();
-        std::string uuid = charset::FromWide( netResources->lpRemoteName ).get();
+        auto utf8_local = charset::FromWide( netResources->lpLocalName );
+        auto utf8_remote = charset::FromWide( netResources->lpRemoteName );
+        if ( !utf8_local || !utf8_remote )
+            continue;
+
+        std::string mountpoint = utf8_local.get();
+        std::string uuid = utf8_remote.get();
         devs.emplace_back( std::move( uuid ),
             std::vector<std::string>{ utils::file::toMrl( mountpoint ) }, true );
     } while ( true );
@@ -118,7 +123,10 @@ std::vector<CommonDeviceLister::Device> DeviceLister::localDevices() const
 
         if ( GetVolumePathNamesForVolumeName( volumeName, buffer, buffLength, &buffLength ) == 0 )
             continue;
-        std::string mountpoint = charset::FromWide( buffer ).get();
+        auto utf8_buffer = charset::FromWide( buffer );
+        if ( !utf8_buffer )
+            continue;
+        std::string mountpoint = utf8_buffer.get();
 
         // Filter out anything which isn't a removable or fixed drive. We don't care about network
         // drive here.
@@ -126,7 +134,10 @@ std::vector<CommonDeviceLister::Device> DeviceLister::localDevices() const
         if ( type != DRIVE_REMOVABLE && type != DRIVE_FIXED && type != DRIVE_REMOTE )
             continue;
 
-        std::string uuid =  charset::FromWide( volumeName ).get();
+        auto utf8_volume = charset::FromWide( volumeName );
+        if ( !utf8_volume )
+            continue;
+        std::string uuid =  utf8_volume.get();
 
         LOG_INFO( "Discovered device ", uuid, "; mounted on ", mountpoint, "; removable: ",
                   type == DRIVE_REMOVABLE ? "yes" : "no" );