private static unsafe void SetWindowsGraphicalUserInterfaceBit()

in src/Tasks/Microsoft.NET.Build.Tasks/AppHost.cs [275:313]

29 lines of code
4 McCabe index (conditional complexity)


        private static unsafe void SetWindowsGraphicalUserInterfaceBit(
            MemoryMappedViewAccessor accessor,
            string appHostSourcePath)
        {
            byte* pointer = null;

            try
            {
                accessor.SafeMemoryMappedViewHandle.AcquirePointer(ref pointer);
                byte* bytes = pointer + accessor.PointerOffset;

                // https://en.wikipedia.org/wiki/Portable_Executable
                UInt32 peHeaderOffset = ((UInt32*)(bytes + PEHeaderPointerOffset))[0];

                if (accessor.Capacity < peHeaderOffset + SubsystemOffset + sizeof(UInt16))
                {
                    throw new BuildErrorException(Strings.AppHostNotWindows, appHostSourcePath);
                }

                UInt16* subsystem = ((UInt16*)(bytes + peHeaderOffset + SubsystemOffset));

                // https://docs.microsoft.com/en-us/windows/desktop/Debug/pe-format#windows-subsystem
                // The subsystem of the prebuilt apphost should be set to CUI
                if (subsystem[0] != WindowsCUISubsystem)
                {
                    throw new BuildErrorException(Strings.AppHostNotWindowsCLI, appHostSourcePath);
                }

                // Set the subsystem to GUI
                subsystem[0] = WindowsGUISubsystem;
            }
            finally
            {
                if (pointer != null)
                {
                    accessor.SafeMemoryMappedViewHandle.ReleasePointer();
                }
            }
        }