Remove AOT warnings for S.Drawing.Common (#61567)

* Remove AOT warnings for S.Drawing.Common
- `Marshal.SizeOf(Type)` replaced with `Marshal.SizeOt<T>()`
- `Marshal.PtrToStructure(IntrPtr, Type)` replaced with `Marshal.PtrToStructure<T>(IntPtr)`

* Use pointers where possible

* Ref return PRINTDLG

* Use GeneratedDllImport

Co-authored-by: Jan Kotas <jkotas@microsoft.com>

src/libraries/System.Drawing.Common/src/Interop/Windows/Interop.Comdlg32.cs

@@ -8,17 +8,14 @@ internal static partial class Interop
 {
     internal static partial class Comdlg32
     {
-#pragma warning disable DLLIMPORTGENANALYZER015 // Use 'GeneratedDllImportAttribute' instead of 'DllImportAttribute' to generate P/Invoke marshalling code at compile time
-        // TODO: [DllImportGenerator] Switch to use GeneratedDllImport once we support non-blittable structs.
-        [DllImport(Libraries.Comdlg32, CharSet = CharSet.Auto, SetLastError = true)]
-        internal static extern bool PrintDlg([In, Out] PRINTDLG lppd);
+        [GeneratedDllImport(Libraries.Comdlg32, CharSet = CharSet.Auto, SetLastError = true)]
+        internal static partial bool PrintDlg(ref PRINTDLG lppd);
 
-        [DllImport(Libraries.Comdlg32, CharSet = CharSet.Auto, SetLastError = true)]
-        internal static extern bool PrintDlg([In, Out] PRINTDLGX86 lppd);
-#pragma warning restore DLLIMPORTGENANALYZER015
+        [GeneratedDllImport(Libraries.Comdlg32, CharSet = CharSet.Auto, SetLastError = true)]
+        internal static partial bool PrintDlg(ref PRINTDLGX86 lppd);
 
-        [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Auto)]
-        internal sealed class PRINTDLG
+        [StructLayout(LayoutKind.Sequential)]
+        internal struct PRINTDLG
         {
             internal int lStructSize;
             internal IntPtr hwndOwner;
@@ -35,14 +32,14 @@ internal sealed class PRINTDLG
             internal IntPtr lCustData;
             internal IntPtr lpfnPrintHook;
             internal IntPtr lpfnSetupHook;
-            internal string? lpPrintTemplateName;
-            internal string? lpSetupTemplateName;
+            internal IntPtr lpPrintTemplateName;
+            internal IntPtr lpSetupTemplateName;
             internal IntPtr hPrintTemplate;
             internal IntPtr hSetupTemplate;
         }
 
-        [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Auto, Pack = 1)]
-        internal sealed class PRINTDLGX86
+        [StructLayout(LayoutKind.Sequential, Pack = 1)]
+        internal struct PRINTDLGX86
         {
             internal int lStructSize;
             internal IntPtr hwndOwner;
@@ -59,8 +56,8 @@ internal sealed class PRINTDLGX86
             internal IntPtr lCustData;
             internal IntPtr lpfnPrintHook;
             internal IntPtr lpfnSetupHook;
-            internal string? lpPrintTemplateName;
-            internal string? lpSetupTemplateName;
+            internal IntPtr lpPrintTemplateName;
+            internal IntPtr lpSetupTemplateName;
             internal IntPtr hPrintTemplate;
             internal IntPtr hSetupTemplate;
         }

src/libraries/System.Drawing.Common/src/System.Drawing.Common.csproj

@@ -174,6 +174,7 @@ Unix support is disabled by default. See https://aka.ms/systemdrawingnonwindows
     <Compile Include="System\Drawing\Imaging\ColorMatrix.cs" />
     <Compile Include="System\Drawing\Imaging\ColorPalette.cs" />
     <Compile Include="System\Drawing\Imaging\EncoderParameter.cs" />
+    <Compile Include="System\Drawing\Imaging\EncoderParameterPrivate.cs" />
     <Compile Include="System\Drawing\Imaging\EncoderParameters.cs" />
     <Compile Include="System\Drawing\Imaging\ImageAttributes.cs" />
     <Compile Include="System\Drawing\Imaging\ImageCodecInfo.cs" />

src/libraries/System.Drawing.Common/src/System/Drawing/Gdiplus.cs

@@ -367,14 +367,14 @@ public const int
         public const int ERROR_CANCELLED = 1223;
 
         [StructLayout(LayoutKind.Sequential)]
-        public class ENHMETAHEADER
+        public struct ENHMETAHEADER
         {
             /// The ENHMETAHEADER structure is defined natively as a union with WmfHeader.
             /// Extreme care should be taken if changing the layout of the corresponding managed
             /// structures to minimize the risk of buffer overruns.  The affected managed classes
             /// are the following: ENHMETAHEADER, MetaHeader, MetafileHeaderWmf, MetafileHeaderEmf.
             public int iType;
-            public int nSize = 40; // ndirect.DllLib.sizeOf( this )
+            public int nSize;
             // rclBounds was a by-value RECTL structure
             public int rclBounds_left;
             public int rclBounds_top;

src/libraries/System.Drawing.Common/src/System/Drawing/Graphics.Unix.cs

@@ -167,7 +167,7 @@ private void CopyFromScreenX11(int sourceX, int sourceY, int destinationX, int d
             /* Get XVisualInfo for this visual */
             visual.visualid = LibX11Functions.XVisualIDFromVisual(defvisual);
             vPtr = LibX11Functions.XGetVisualInfo(Gdip.Display, 0x1 /* VisualIDMask */, ref visual, ref nitems);
-            visual = (XVisualInfo)Marshal.PtrToStructure(vPtr, typeof(XVisualInfo))!;
+            visual = Marshal.PtrToStructure<XVisualInfo>(vPtr)!;
             image = LibX11Functions.XGetImage(Gdip.Display, window, sourceX, sourceY, blockRegionSize.Width,
                 blockRegionSize.Height, AllPlanes, 2 /* ZPixmap*/);
             if (image == IntPtr.Zero)

src/libraries/System.Drawing.Common/src/System/Drawing/Imaging/EncoderParameter.cs

@@ -9,9 +9,6 @@ namespace System.Drawing.Imaging
     [StructLayout(LayoutKind.Sequential)]
     public sealed unsafe class EncoderParameter : IDisposable
     {
-#pragma warning disable CS0618 // Legacy code: We don't care about using obsolete API's.
-        [MarshalAs(UnmanagedType.Struct)]
-#pragma warning restore CS0618
         private Guid _parameterGuid;                    // GUID of the parameter
         private readonly int _numberOfValues;                    // Number of the parameter values
         private readonly EncoderParameterValueType _parameterValueType;   // Value type, like ValueTypeLONG  etc.

src/libraries/System.Drawing.Common/src/System/Drawing/Imaging/EncoderParameterPrivate.cs

@@ -0,0 +1,16 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System.Runtime.InteropServices;
+
+namespace System.Drawing.Imaging
+{
+    [StructLayout(LayoutKind.Sequential)]
+    internal struct EncoderParameterPrivate
+    {
+        public Guid ParameterGuid;                    // GUID of the parameter
+        public int NumberOfValues;                    // Number of the parameter values
+        public EncoderParameterValueType ParameterValueType; // Value type, like ValueTypeLONG  etc.
+        public IntPtr ParameterValue;                 // A pointer to the parameter values
+    }
+}

src/libraries/System.Drawing.Common/src/System/Drawing/Imaging/EncoderParameters.cs

@@ -51,9 +51,9 @@ public EncoderParameter[] Param
         /// Also, in 64-bit platforms, 'Count' is aligned in 8 bytes (4 extra padding bytes) so we use IntPtr instead of Int32 to account for
         /// that.
         /// </summary>
-        internal IntPtr ConvertToMemory()
+        internal unsafe IntPtr ConvertToMemory()
         {
-            int size = Marshal.SizeOf(typeof(EncoderParameter));
+            int size = sizeof(EncoderParameterPrivate);
 
             int length = _param.Length;
             IntPtr memory = Marshal.AllocHGlobal(checked(length * size + IntPtr.Size));
@@ -74,27 +74,21 @@ internal IntPtr ConvertToMemory()
         /// Copy the native GDI+ EncoderParameters data from a chunk of memory into a managed EncoderParameters object.
         /// See ConvertToMemory for more info.
         /// </summary>
-        internal static EncoderParameters ConvertFromMemory(IntPtr memory)
+        internal static unsafe EncoderParameters ConvertFromMemory(IntPtr memory)
         {
             if (memory == IntPtr.Zero)
             {
                 throw Gdip.StatusException(Gdip.InvalidParameter);
             }
 
-            int count = Marshal.ReadInt32(memory);
-
+            int count = *(int*)memory;
+            EncoderParameterPrivate* parameters = (EncoderParameterPrivate*)((byte*)memory + IntPtr.Size);
             EncoderParameters p = new EncoderParameters(count);
-            int size = Marshal.SizeOf(typeof(EncoderParameter));
-            long arrayOffset = (long)memory + IntPtr.Size;
-
             for (int i = 0; i < count; i++)
             {
-                Guid guid = (Guid)Marshal.PtrToStructure((IntPtr)(i * size + arrayOffset), typeof(Guid))!;
-                int numberOfValues = Marshal.ReadInt32((IntPtr)(i * size + arrayOffset + 16));
-                EncoderParameterValueType type = (EncoderParameterValueType)Marshal.ReadInt32((IntPtr)(i * size + arrayOffset + 20));
-                IntPtr value = Marshal.ReadIntPtr((IntPtr)(i * size + arrayOffset + 24));
+                ref readonly EncoderParameterPrivate param = ref parameters[i];
 
-                p._param[i] = new EncoderParameter(new Encoder(guid), numberOfValues, type, value);
+                p._param[i] = new EncoderParameter(new Encoder(param.ParameterGuid), param.NumberOfValues, param.ParameterValueType, param.ParameterValue);
             }
 
             return p;

src/libraries/System.Drawing.Common/src/System/Drawing/Imaging/ImageCodecInfo.cs

@@ -169,41 +169,38 @@ public static ImageCodecInfo[] GetImageEncoders()
             return imageCodecs;
         }
 
-        private static ImageCodecInfo[] ConvertFromMemory(IntPtr memoryStart, int numCodecs)
+        private static unsafe ImageCodecInfo[] ConvertFromMemory(IntPtr memoryStart, int numCodecs)
         {
             ImageCodecInfo[] codecs = new ImageCodecInfo[numCodecs];
 
             int index;
 
             for (index = 0; index < numCodecs; index++)
             {
-                IntPtr curcodec = (IntPtr)((long)memoryStart + (int)Marshal.SizeOf(typeof(ImageCodecInfoPrivate)) * index);
-                ImageCodecInfoPrivate codecp = new ImageCodecInfoPrivate();
-                Marshal.PtrToStructure(curcodec, codecp);
+                ref readonly ImageCodecInfoPrivate codecp = ref ((ImageCodecInfoPrivate*)memoryStart)[index];
 
-                codecs[index] = new ImageCodecInfo();
-                codecs[index].Clsid = codecp.Clsid;
-                codecs[index].FormatID = codecp.FormatID;
-                codecs[index].CodecName = Marshal.PtrToStringUni(codecp.CodecName);
-                codecs[index].DllName = Marshal.PtrToStringUni(codecp.DllName);
-                codecs[index].FormatDescription = Marshal.PtrToStringUni(codecp.FormatDescription);
-                codecs[index].FilenameExtension = Marshal.PtrToStringUni(codecp.FilenameExtension);
-                codecs[index].MimeType = Marshal.PtrToStringUni(codecp.MimeType);
+                var codec = new ImageCodecInfo();
+                codec.Clsid = codecp.Clsid;
+                codec.FormatID = codecp.FormatID;
+                codec.CodecName = Marshal.PtrToStringUni(codecp.CodecName);
+                codec.DllName = Marshal.PtrToStringUni(codecp.DllName);
+                codec.FormatDescription = Marshal.PtrToStringUni(codecp.FormatDescription);
+                codec.FilenameExtension = Marshal.PtrToStringUni(codecp.FilenameExtension);
+                codec.MimeType = Marshal.PtrToStringUni(codecp.MimeType);
 
-                codecs[index].Flags = (ImageCodecFlags)codecp.Flags;
-                codecs[index].Version = (int)codecp.Version;
+                codec.Flags = (ImageCodecFlags)codecp.Flags;
+                codec.Version = (int)codecp.Version;
 
-                codecs[index].SignaturePatterns = new byte[codecp.SigCount][];
-                codecs[index].SignatureMasks = new byte[codecp.SigCount][];
+                codec.SignaturePatterns = new byte[codecp.SigCount][];
+                codec.SignatureMasks = new byte[codecp.SigCount][];
 
                 for (int j = 0; j < codecp.SigCount; j++)
                 {
-                    codecs[index].SignaturePatterns![j] = new byte[codecp.SigSize];
-                    codecs[index].SignatureMasks![j] = new byte[codecp.SigSize];
-
-                    Marshal.Copy((IntPtr)((long)codecp.SigMask + j * codecp.SigSize), codecs[index].SignatureMasks![j], 0, codecp.SigSize);
-                    Marshal.Copy((IntPtr)((long)codecp.SigPattern + j * codecp.SigSize), codecs[index].SignaturePatterns![j], 0, codecp.SigSize);
+                    codec.SignaturePatterns[j] = new ReadOnlySpan<byte>((byte*)codecp.SigPattern + j * codecp.SigSize, codecp.SigSize).ToArray();
+                    codec.SignatureMasks[j] = new ReadOnlySpan<byte>((byte*)codecp.SigMask + j * codecp.SigSize, codecp.SigSize).ToArray();
                 }
+
+                codecs[index] = codec;
             }
 
             return codecs;

src/libraries/System.Drawing.Common/src/System/Drawing/Imaging/ImageCodecInfoPrivate.cs

@@ -7,29 +7,24 @@ namespace System.Drawing.Imaging
 
     // sdkinc\imaging.h
     [StructLayout(LayoutKind.Sequential, Pack = 8)]
-    internal sealed class ImageCodecInfoPrivate
+    internal struct ImageCodecInfoPrivate
     {
-#pragma warning disable CS0618 // Legacy code: We don't care about using obsolete API's.
-        [MarshalAs(UnmanagedType.Struct)]
-#pragma warning restore CS0618
         public Guid Clsid;
-#pragma warning disable CS0618 // Legacy code: We don't care about using obsolete API's.
-        [MarshalAs(UnmanagedType.Struct)]
-#pragma warning restore CS0618
+
         public Guid FormatID;
 
-        public IntPtr CodecName = IntPtr.Zero;
-        public IntPtr DllName = IntPtr.Zero;
-        public IntPtr FormatDescription = IntPtr.Zero;
-        public IntPtr FilenameExtension = IntPtr.Zero;
-        public IntPtr MimeType = IntPtr.Zero;
+        public IntPtr CodecName;
+        public IntPtr DllName;
+        public IntPtr FormatDescription;
+        public IntPtr FilenameExtension;
+        public IntPtr MimeType;
 
         public int Flags;
         public int Version;
         public int SigCount;
         public int SigSize;
 
-        public IntPtr SigPattern = IntPtr.Zero;
-        public IntPtr SigMask = IntPtr.Zero;
+        public IntPtr SigPattern;
+        public IntPtr SigMask;
     }
 }

src/libraries/System.Drawing.Common/src/System/Drawing/Imaging/Metafile.Unix.cs

@@ -255,7 +255,7 @@ public IntPtr GetHenhmetafile()
 
         public MetafileHeader GetMetafileHeader()
         {
-            IntPtr header = Marshal.AllocHGlobal(Marshal.SizeOf(typeof(MetafileHeader)));
+            IntPtr header = Marshal.AllocHGlobal(Marshal.SizeOf<MetafileHeader>());
             try
             {
                 int status = Gdip.GdipGetMetafileHeaderFromMetafile(nativeImage, header);
@@ -270,7 +270,7 @@ public MetafileHeader GetMetafileHeader()
 
         public static MetafileHeader GetMetafileHeader(IntPtr henhmetafile)
         {
-            IntPtr header = Marshal.AllocHGlobal(Marshal.SizeOf(typeof(MetafileHeader)));
+            IntPtr header = Marshal.AllocHGlobal(Marshal.SizeOf<MetafileHeader>());
             try
             {
                 int status = Gdip.GdipGetMetafileHeaderFromEmf(henhmetafile, header);
@@ -288,7 +288,7 @@ public static MetafileHeader GetMetafileHeader(Stream stream)
             if (stream == null)
                 throw new NullReferenceException(nameof(stream));
 
-            IntPtr header = Marshal.AllocHGlobal(Marshal.SizeOf(typeof(MetafileHeader)));
+            IntPtr header = Marshal.AllocHGlobal(Marshal.SizeOf<MetafileHeader>());
             try
             {
                 // With libgdiplus we use a custom API for this, because there's no easy way
@@ -315,7 +315,7 @@ public static MetafileHeader GetMetafileHeader(string fileName)
             // Called in order to emulate exception behavior from .NET Framework related to invalid file paths.
             Path.GetFullPath(fileName);
 
-            IntPtr header = Marshal.AllocHGlobal(Marshal.SizeOf(typeof(MetafileHeader)));
+            IntPtr header = Marshal.AllocHGlobal(Marshal.SizeOf<MetafileHeader>());
             try
             {
                 int status = Gdip.GdipGetMetafileHeaderFromFile(fileName, header);
@@ -330,7 +330,7 @@ public static MetafileHeader GetMetafileHeader(string fileName)
 
         public static MetafileHeader GetMetafileHeader(IntPtr hmetafile, WmfPlaceableFileHeader wmfHeader)
         {
-            IntPtr header = Marshal.AllocHGlobal(Marshal.SizeOf(typeof(MetafileHeader)));
+            IntPtr header = Marshal.AllocHGlobal(Marshal.SizeOf<MetafileHeader>());
             try
             {
                 int status = Gdip.GdipGetMetafileHeaderFromEmf(hmetafile, header);

src/libraries/System.Drawing.Common/src/System/Drawing/Imaging/Metafile.Windows.cs

@@ -257,7 +257,7 @@ public static MetafileHeader GetMetafileHeader(string fileName)
 
             MetafileHeader header = new MetafileHeader();
 
-            IntPtr memory = Marshal.AllocHGlobal(Marshal.SizeOf(typeof(MetafileHeaderEmf)));
+            IntPtr memory = Marshal.AllocHGlobal(Marshal.SizeOf<MetafileHeaderEmf>());
 
             try
             {
@@ -273,14 +273,14 @@ public static MetafileHeader GetMetafileHeader(string fileName)
                     metafileType == MetafileType.WmfPlaceable)
                 {
                     // WMF header
-                    header.wmf = (MetafileHeaderWmf)Marshal.PtrToStructure(memory, typeof(MetafileHeaderWmf))!;
+                    header.wmf = Marshal.PtrToStructure<MetafileHeaderWmf>(memory)!;
                     header.emf = null;
                 }
                 else
                 {
                     // EMF header
                     header.wmf = null;
-                    header.emf = (MetafileHeaderEmf)Marshal.PtrToStructure(memory, typeof(MetafileHeaderEmf))!;
+                    header.emf = Marshal.PtrToStructure<MetafileHeaderEmf>(memory)!;
                 }
             }
             finally
@@ -298,7 +298,7 @@ public static MetafileHeader GetMetafileHeader(Stream stream)
         {
             MetafileHeader header;
 
-            IntPtr memory = Marshal.AllocHGlobal(Marshal.SizeOf(typeof(MetafileHeaderEmf)));
+            IntPtr memory = Marshal.AllocHGlobal(Marshal.SizeOf<MetafileHeaderEmf>());
 
             try
             {
@@ -317,14 +317,14 @@ public static MetafileHeader GetMetafileHeader(Stream stream)
                     metafileType == MetafileType.WmfPlaceable)
                 {
                     // WMF header
-                    header.wmf = (MetafileHeaderWmf)Marshal.PtrToStructure(memory, typeof(MetafileHeaderWmf))!;
+                    header.wmf = Marshal.PtrToStructure<MetafileHeaderWmf>(memory)!;
                     header.emf = null;
                 }
                 else
                 {
                     // EMF header
                     header.wmf = null;
-                    header.emf = (MetafileHeaderEmf)Marshal.PtrToStructure(memory, typeof(MetafileHeaderEmf))!;
+                    header.emf = Marshal.PtrToStructure<MetafileHeaderEmf>(memory)!;
                 }
             }
             finally
@@ -342,7 +342,7 @@ public MetafileHeader GetMetafileHeader()
         {
             MetafileHeader header;
 
-            IntPtr memory = Marshal.AllocHGlobal(Marshal.SizeOf(typeof(MetafileHeaderEmf)));
+            IntPtr memory = Marshal.AllocHGlobal(Marshal.SizeOf<MetafileHeaderEmf>());
 
             try
             {
@@ -360,14 +360,14 @@ public MetafileHeader GetMetafileHeader()
                     metafileType == MetafileType.WmfPlaceable)
                 {
                     // WMF header
-                    header.wmf = (MetafileHeaderWmf)Marshal.PtrToStructure(memory, typeof(MetafileHeaderWmf))!;
+                    header.wmf = Marshal.PtrToStructure<MetafileHeaderWmf>(memory)!;
                     header.emf = null;
                 }
                 else
                 {
                     // EMF header
                     header.wmf = null;
-                    header.emf = (MetafileHeaderEmf)Marshal.PtrToStructure(memory, typeof(MetafileHeaderEmf))!;
+                    header.emf = Marshal.PtrToStructure<MetafileHeaderEmf>(memory)!;
                 }
             }
             finally

src/libraries/System.Drawing.Common/src/System/Drawing/Imaging/MetafileHeader.Unix.cs

@@ -103,7 +103,7 @@ public sealed class MetafileHeader
 
         internal MetafileHeader(IntPtr henhmetafile)
         {
-            Marshal.PtrToStructure(henhmetafile, this);
+            Marshal.PtrToStructure<MetafileHeader>(henhmetafile, this);
         }
 
         // methods

src/libraries/System.Drawing.Common/src/System/Drawing/Imaging/MetafileHeaderWmf.cs

@@ -13,7 +13,7 @@ internal sealed class MetafileHeaderWmf
         /// structures to minimize the risk of buffer overruns.  The affected managed classes
         /// are the following: ENHMETAHEADER, MetaHeader, MetafileHeaderWmf, MetafileHeaderEmf.
         public MetafileType type = MetafileType.Invalid;
-        public int size = Marshal.SizeOf(typeof(MetafileHeaderWmf));
+        public int size = Marshal.SizeOf<MetafileHeaderWmf>();
         public int version;
         public EmfPlusFlags emfPlusFlags;
         public float dpiX;