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// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
using System;
using System.Collections.Generic;
using System.IO;
using System.Numerics;
using System.Reflection.Metadata;
using System.Reflection.PortableExecutable;
using System.Runtime.InteropServices;
namespace Microsoft.Diagnostics.DataContractReader.Contracts;
internal sealed class EcmaMetadata_1(Target target) : IEcmaMetadata
{
private Dictionary<ModuleHandle, MetadataReaderProvider?> _metadata = new();
public void Flush()
{
_metadata.Clear();
}
public TargetSpan GetReadOnlyMetadataAddress(ModuleHandle handle)
{
ILoader loader = target.Contracts.Loader;
if (!loader.TryGetLoadedImageContents(handle, out TargetPointer baseAddress, out uint size, out uint imageFlags))
{
throw new InvalidOperationException("Module is not loaded.");
}
bool isMapped = (imageFlags & 0x1) != 0; // FLAG_MAPPED = 0x1
PEStreamOptions isLoaded = isMapped ? PEStreamOptions.IsLoadedImage : PEStreamOptions.Default;
TargetStream stream = new(target, baseAddress, size);
using PEReader peReader = new PEReader(stream, PEStreamOptions.PrefetchMetadata | isLoaded);
int metadataStartOffset = peReader.PEHeaders.MetadataStartOffset;
int metadataSize = peReader.PEHeaders.MetadataSize;
return new TargetSpan(baseAddress + (ulong)metadataStartOffset, (ulong)metadataSize);
}
public MetadataReader? GetMetadata(ModuleHandle handle)
{
if (_metadata.TryGetValue(handle, out MetadataReaderProvider? result))
{
return result?.GetMetadataReader();
}
else
{
MetadataReaderProvider? provider = GetMetadataProvider(handle);
_metadata.Add(handle, provider);
return provider?.GetMetadataReader();
}
}
private MetadataReaderProvider? GetMetadataProvider(ModuleHandle handle)
{
AvailableMetadataType type = GetAvailableMetadataType(handle);
switch (type)
{
case AvailableMetadataType.None:
return null;
case AvailableMetadataType.ReadOnly:
{
TargetSpan address = GetReadOnlyMetadataAddress(handle);
byte[] data = new byte[address.Size];
target.ReadBuffer(address.Address, data);
return MetadataReaderProvider.FromMetadataImage(ImmutableCollectionsMarshal.AsImmutableArray(data));
}
case AvailableMetadataType.ReadWriteSavedCopy:
{
TargetSpan address = GetReadWriteSavedMetadataAddress(handle);
byte[] data = new byte[address.Size];
target.ReadBuffer(address.Address, data);
return MetadataReaderProvider.FromMetadataImage(ImmutableCollectionsMarshal.AsImmutableArray(data));
}
case AvailableMetadataType.ReadWrite:
{
var targetEcmaMetadata = GetReadWriteMetadata(handle);
// From the multiple different target spans, we need to build a single
// contiguous ECMA-335 metadata blob.
BlobBuilder builder = new BlobBuilder();
builder.WriteUInt32(0x424A5342);
// major version
builder.WriteUInt16(1);
// minor version
builder.WriteUInt16(1);
// reserved
builder.WriteUInt32(0);
string version = targetEcmaMetadata.Schema.MetadataVersion;
builder.WriteInt32(AlignUp(version.Length, 4));
Write4ByteAlignedString(builder, version);
// reserved
builder.WriteUInt16(0);
// number of streams
ushort numStreams = 5; // #Strings, #US, #Blob, #GUID, #~ (metadata)
if (targetEcmaMetadata.Schema.VariableSizedColumnsAreAll4BytesLong)
{
// We direct MetadataReader to use 4-byte encoding for all variable-sized columns
// by providing the marker stream for a "minimal delta" image.
numStreams++;
}
builder.WriteUInt16(numStreams);
// Write Stream headers
if (targetEcmaMetadata.Schema.VariableSizedColumnsAreAll4BytesLong)
{
// Write the #JTD stream to indicate that all variable-sized columns are 4 bytes long.
WriteStreamHeader(builder, "#JTD", 0).WriteInt32(builder.Count);
}
BlobWriter stringsOffset = WriteStreamHeader(builder, "#Strings", (int)AlignUp(targetEcmaMetadata.StringHeap.Size, 4ul));
BlobWriter blobOffset = WriteStreamHeader(builder, "#Blob", (int)targetEcmaMetadata.BlobHeap.Size);
BlobWriter guidOffset = WriteStreamHeader(builder, "#GUID", (int)targetEcmaMetadata.GuidHeap.Size);
BlobWriter userStringOffset = WriteStreamHeader(builder, "#US", (int)targetEcmaMetadata.UserStringHeap.Size);
// We'll use the "uncompressed" tables stream name as the runtime may have created the *Ptr tables
// that are only present in the uncompressed tables stream.
BlobWriter tablesOffset = WriteStreamHeader(builder, "#-", 0);
// Write the heap-style Streams
stringsOffset.WriteInt32(builder.Count);
WriteTargetSpan(builder, targetEcmaMetadata.StringHeap);
for (ulong i = targetEcmaMetadata.StringHeap.Size; i < AlignUp(targetEcmaMetadata.StringHeap.Size, 4ul); i++)
{
builder.WriteByte(0);
}
blobOffset.WriteInt32(builder.Count);
WriteTargetSpan(builder, targetEcmaMetadata.BlobHeap);
guidOffset.WriteInt32(builder.Count);
WriteTargetSpan(builder, targetEcmaMetadata.GuidHeap);
userStringOffset.WriteInt32(builder.Count);
WriteTargetSpan(builder, targetEcmaMetadata.UserStringHeap);
// Write tables stream
tablesOffset.WriteInt32(builder.Count);
// Write tables stream header
builder.WriteInt32(0); // reserved
builder.WriteByte(2); // major version
builder.WriteByte(0); // minor version
uint heapSizes =
(targetEcmaMetadata.Schema.LargeStringHeap ? 1u << 0 : 0) |
(targetEcmaMetadata.Schema.LargeBlobHeap ? 1u << 1 : 0) |
(targetEcmaMetadata.Schema.LargeGuidHeap ? 1u << 2 : 0);
builder.WriteByte((byte)heapSizes);
builder.WriteByte(1); // reserved
ulong validTables = 0;
for (int i = 0; i < targetEcmaMetadata.Schema.RowCount.Length; i++)
{
if (targetEcmaMetadata.Schema.RowCount[i] != 0)
{
validTables |= 1ul << i;
}
}
ulong sortedTables = 0;
for (int i = 0; i < targetEcmaMetadata.Schema.IsSorted.Length; i++)
{
if (targetEcmaMetadata.Schema.IsSorted[i])
{
sortedTables |= 1ul << i;
}
}
builder.WriteUInt64(validTables);
builder.WriteUInt64(sortedTables);
foreach (int rowCount in targetEcmaMetadata.Schema.RowCount)
{
if (rowCount > 0)
{
builder.WriteInt32(rowCount);
}
}
// Write the tables
foreach (TargetSpan span in targetEcmaMetadata.Tables)
{
WriteTargetSpan(builder, span);
}
MemoryStream metadataStream = new MemoryStream();
builder.WriteContentTo(metadataStream);
return MetadataReaderProvider.FromMetadataStream(metadataStream);
void WriteTargetSpan(BlobBuilder builder, TargetSpan span)
{
Blob blob = builder.ReserveBytes(checked((int)span.Size));
target.ReadBuffer(span.Address, blob.GetBytes().AsSpan());
}
static BlobWriter WriteStreamHeader(BlobBuilder builder, string name, int size)
{
BlobWriter offset = new(builder.ReserveBytes(4));
builder.WriteInt32(size);
Write4ByteAlignedString(builder, name);
return offset;
}
static void Write4ByteAlignedString(BlobBuilder builder, string value)
{
int bufferStart = builder.Count;
builder.WriteUTF8(value);
builder.WriteByte(0);
int stringEnd = builder.Count;
for (int i = stringEnd; i < bufferStart + AlignUp(value.Length, 4); i++)
{
builder.WriteByte(0);
}
}
}
default:
throw new NotImplementedException();
}
}
private struct EcmaMetadataSchema
{
public EcmaMetadataSchema(string metadataVersion, bool largeStringHeap, bool largeBlobHeap, bool largeGuidHeap, int[] rowCount, bool[] isSorted, bool variableSizedColumnsAre4BytesLong)
{
MetadataVersion = metadataVersion;
LargeStringHeap = largeStringHeap;
LargeBlobHeap = largeBlobHeap;
LargeGuidHeap = largeGuidHeap;
_rowCount = rowCount;
_isSorted = isSorted;
VariableSizedColumnsAreAll4BytesLong = variableSizedColumnsAre4BytesLong;
}
public readonly string MetadataVersion;
public readonly bool LargeStringHeap;
public readonly bool LargeBlobHeap;
public readonly bool LargeGuidHeap;
// Table data, these structures hold MetadataTable.Count entries
private readonly int[] _rowCount;
public readonly ReadOnlySpan<int> RowCount => _rowCount;
private readonly bool[] _isSorted;
public readonly ReadOnlySpan<bool> IsSorted => _isSorted;
// In certain scenarios the size of the tables is forced to be the maximum size
// Otherwise the size of columns should be computed based on RowSize/the various heap flags
public readonly bool VariableSizedColumnsAreAll4BytesLong;
}
private sealed class TargetEcmaMetadata
{
public TargetEcmaMetadata(EcmaMetadataSchema schema,
TargetSpan[] tables,
TargetSpan stringHeap,
TargetSpan userStringHeap,
TargetSpan blobHeap,
TargetSpan guidHeap)
{
Schema = schema;
_tables = tables;
StringHeap = stringHeap;
UserStringHeap = userStringHeap;
BlobHeap = blobHeap;
GuidHeap = guidHeap;
}
public EcmaMetadataSchema Schema { get; init; }
private TargetSpan[] _tables;
public ReadOnlySpan<TargetSpan> Tables => _tables;
public TargetSpan StringHeap { get; init; }
public TargetSpan UserStringHeap { get; init; }
public TargetSpan BlobHeap { get; init; }
public TargetSpan GuidHeap { get; init; }
}
[Flags]
private enum AvailableMetadataType
{
None = 0,
ReadOnly = 1,
ReadWriteSavedCopy = 2,
ReadWrite = 4
}
private AvailableMetadataType GetAvailableMetadataType(ModuleHandle handle)
{
Data.Module module = target.ProcessedData.GetOrAdd<Data.Module>(handle.Address);
AvailableMetadataType flags = AvailableMetadataType.None;
if (module.DynamicMetadata != TargetPointer.Null)
flags |= AvailableMetadataType.ReadWriteSavedCopy;
else
flags |= AvailableMetadataType.ReadOnly;
// TODO(cdac) implement direct reading of unsaved ReadWrite metadata
return flags;
}
private TargetSpan GetReadWriteSavedMetadataAddress(ModuleHandle handle)
{
Data.Module module = target.ProcessedData.GetOrAdd<Data.Module>(handle.Address);
Data.DynamicMetadata dynamicMetadata = target.ProcessedData.GetOrAdd<Data.DynamicMetadata>(module.DynamicMetadata);
return new TargetSpan(dynamicMetadata.Data, dynamicMetadata.Size);
}
private TargetEcmaMetadata GetReadWriteMetadata(ModuleHandle handle)
{
throw new NotImplementedException();
}
private static T AlignUp<T>(T input, T alignment)
where T : IBinaryInteger<T>
{
return input + (alignment - T.One) & ~(alignment - T.One);
}
}
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