// 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.Concurrent;
using System.Collections.Generic;
using System.Diagnostics;
using System.Diagnostics.CodeAnalysis;
using System.IO;
using System.Linq;
using System.Reflection;
using System.Reflection.Metadata;
using System.Reflection.Metadata.Ecma335;
using System.Reflection.PortableExecutable;
#if NET
using System.Runtime.CompilerServices;
#endif
using System.Runtime.InteropServices;
using System.Threading;
using Microsoft.Build.Eventing;
using Microsoft.Build.Framework;
using static Microsoft.Build.Shared.XMakeAttributes;
#nullable disable
namespace Microsoft.Build.Shared;
/// <summary>
/// This class is used to load types from their assemblies.
/// </summary>
internal class TypeLoader
{
#if NET && FEATURE_ASSEMBLYLOADCONTEXT
/// <summary>
/// AssemblyContextLoader used to load DLLs outside of msbuild.exe directory
/// </summary>
private static readonly CoreClrAssemblyLoader s_coreClrAssemblyLoader = new CoreClrAssemblyLoader();
#endif
/// <summary>
/// Assembly name that indicates .NET Core/5+ if present as a referenced assembly.
/// </summary>
private const string SystemRuntimeAssemblyName = "System.Runtime";
/// <summary>
/// NET target moniker name.
/// </summary>
private const string DotNetCoreIdentifier = ".NETCore";
/// <summary>
/// Assembly custom attribute name.
/// </summary>
private const string TargetFrameworkAttributeName = "TargetFrameworkAttribute";
/// <summary>
/// Versioning namespace name.
/// </summary>
private const string VersioningNamespaceName = "System.Runtime.Versioning";
/// <summary>
/// Cache to keep track of the assemblyLoadInfos based on the desired interface.
/// </summary>
private static readonly ConcurrentDictionary<Type, ConcurrentDictionary<AssemblyLoadInfo, AssemblyInfoToLoadedTypes>> s_cacheOfLoadedTypesByFilter = new ConcurrentDictionary<Type, ConcurrentDictionary<AssemblyLoadInfo, AssemblyInfoToLoadedTypes>>();
/// <summary>
/// Cache to keep track of the assemblyLoadInfos based on the desired interface for assemblies which are to be loaded for reflectionOnlyLoads.
/// </summary>
private static readonly ConcurrentDictionary<Type, ConcurrentDictionary<AssemblyLoadInfo, AssemblyInfoToLoadedTypes>> s_cacheOfReflectionOnlyLoadedTypesByFilter = new ConcurrentDictionary<Type, ConcurrentDictionary<AssemblyLoadInfo, AssemblyInfoToLoadedTypes>>();
/// <summary>
/// The interface that loaded types must implement. Stored as a <see cref="Type"/> so that construction is
/// trim-safe; the actual interface lookup happens by name inside the [RequiresUnreferencedCode] load methods.
/// </summary>
private readonly Type _desiredInterface;
private static readonly string[] runtimeAssemblies = findRuntimeAssembliesWithMicrosoftBuildFramework();
private static string microsoftBuildFrameworkPath;
// We need to append Microsoft.Build.Framework from next to the executing assembly first to make sure it's loaded before the runtime variant.
private static string[] findRuntimeAssembliesWithMicrosoftBuildFramework()
{
string msbuildDirectory = Path.GetDirectoryName(Assembly.GetExecutingAssembly().Location);
microsoftBuildFrameworkPath = Path.Combine(msbuildDirectory, "Microsoft.Build.Framework.dll");
string[] msbuildAssemblies = Directory.GetFiles(msbuildDirectory, "*.dll");
string[] runtimeAssemblies = Directory.GetFiles(RuntimeEnvironment.GetRuntimeDirectory(), "*.dll");
return [.. runtimeAssemblies, .. msbuildAssemblies];
}
#if NETFRAMEWORK
private static readonly Lazy<string[]> runtimeAssembliesCLR35_20 = new Lazy<string[]>(FindRuntimeAssembliesWithMicrosoftBuildFrameworkCLR2CLR35);
/// <summary>
/// Gathers a list of runtime assemblies for the <see cref="MetadataLoadContext"/>.
/// This includes assemblies from the MSBuild installation directory, the current .NET runtime directory,
/// and on .NET Framework, assemblies from older framework versions (2.0, 3.5).
/// The path to the current `Microsoft.Build.Framework.dll` is also stored to ensure it's prioritized
/// for resolving essential types like <see cref="ITaskItem"/>.
/// These paths are used to create a <see cref="PathAssemblyResolver"/> for the <see cref="MetadataLoadContext"/>.
/// </summary>
private static string[] FindRuntimeAssembliesWithMicrosoftBuildFrameworkCLR2CLR35()
{
string v20Path = FrameworkLocationHelper.PathToDotNetFrameworkV20;
string v35Path = FrameworkLocationHelper.PathToDotNetFrameworkV35;
string[] clr2Assemblies = !string.IsNullOrEmpty(v20Path) && Directory.Exists(v20Path)
? Directory.GetFiles(v20Path, "*.dll")
: [];
string[] clr35Assemblies = !string.IsNullOrEmpty(v35Path) && Directory.Exists(v35Path)
? Directory.GetFiles(v35Path, "*.dll")
: [];
// Deduplicate: CLR3.5 assemblies take priority over CLR2 assemblies
Dictionary<string, string> assembliesDictionary = new(StringComparer.OrdinalIgnoreCase);
AddAssembliesToDictionary(assembliesDictionary, clr2Assemblies, clr35Assemblies);
return [.. assembliesDictionary.Values];
}
#endif
/// <summary>
/// Constructor.
/// </summary>
private TypeLoader(Type desiredInterface)
{
_desiredInterface = desiredInterface;
}
/// <summary>
/// Creates a <see cref="TypeLoader"/> that selects concrete, public types implementing <typeparamref name="TInterface"/>
/// (for example <see cref="ITask"/> or <see cref="ILogger"/>).
/// </summary>
/// <remarks>
/// Capturing the interface as data (rather than a filter delegate) keeps construction trim-safe: no reflection
/// happens here, so callers in field initializers and other contexts that are not [RequiresUnreferencedCode] do
/// not produce trim warnings. The interface match runs later, by name, inside the load methods that are already
/// annotated [RequiresUnreferencedCode]; name matching is also the only test that works for types inspected
/// through a <see cref="MetadataLoadContext"/>.
/// </remarks>
internal static TypeLoader Create<TInterface>() where TInterface : class => new TypeLoader(typeof(TInterface));
/// <summary>
/// Delegate used to log warning messages with formatted string support.
/// </summary>
/// <param name="format">A composite format string for the warning message.</param>
/// <param name="args">An array of objects to format into the warning message.</param>
internal delegate void LogWarningDelegate(string format, params object[] args);
/// <summary>
/// Given two type names, looks for a partial match between them. A partial match is considered valid only if it occurs on
/// the right side (tail end) of the name strings, and at the start of a class or namespace name.
/// </summary>
/// <remarks>
/// 1) Matches are case-insensitive.
/// 2) .NET conventions regarding namespaces and nested classes are respected, including escaping of reserved characters.
/// </remarks>
/// <example>
/// "Csc" and "csc" ==> exact match
/// "Microsoft.Build.Tasks.Csc" and "Microsoft.Build.Tasks.Csc" ==> exact match
/// "Microsoft.Build.Tasks.Csc" and "Csc" ==> partial match
/// "Microsoft.Build.Tasks.Csc" and "Tasks.Csc" ==> partial match
/// "MyTasks.ATask+NestedTask" and "NestedTask" ==> partial match
/// "MyTasks.ATask\\+NestedTask" and "NestedTask" ==> partial match
/// "MyTasks.CscTask" and "Csc" ==> no match
/// "MyTasks.MyCsc" and "Csc" ==> no match
/// "MyTasks.ATask\.Csc" and "Csc" ==> no match
/// "MyTasks.ATask\\\.Csc" and "Csc" ==> no match
/// </example>
/// <returns>true, if the type names match exactly or partially; false, if there is no match at all</returns>
internal static bool IsPartialTypeNameMatch(string typeName1, string typeName2)
{
bool isPartialMatch = false;
// if the type names are the same length, a partial match is impossible
if (typeName1.Length != typeName2.Length)
{
string longerTypeName;
string shorterTypeName;
// figure out which type name is longer
if (typeName1.Length > typeName2.Length)
{
longerTypeName = typeName1;
shorterTypeName = typeName2;
}
else
{
longerTypeName = typeName2;
shorterTypeName = typeName1;
}
// if the shorter type name matches the end of the longer one
if (longerTypeName.EndsWith(shorterTypeName, StringComparison.OrdinalIgnoreCase))
{
int matchIndex = longerTypeName.Length - shorterTypeName.Length;
// if the matched sub-string looks like the start of a namespace or class name
if ((longerTypeName[matchIndex - 1] == '.') || (longerTypeName[matchIndex - 1] == '+'))
{
int precedingBackslashes = 0;
// confirm there are zero, or an even number of \'s preceding it...
for (int i = matchIndex - 2; i >= 0; i--)
{
if (longerTypeName[i] == '\\')
{
precedingBackslashes++;
}
else
{
break;
}
}
if ((precedingBackslashes % 2) == 0)
{
isPartialMatch = true;
}
}
}
}
else
{
isPartialMatch = (String.Equals(typeName1, typeName2, StringComparison.OrdinalIgnoreCase));
}
return isPartialMatch;
}
/// <summary>
/// Load an assembly given its AssemblyLoadInfo
/// </summary>
/// <param name="assemblyLoadInfo"></param>
/// <returns></returns>
[RequiresUnreferencedCode("Loads task and factory assemblies discovered at runtime, which is incompatible with trimming.")]
private static Assembly LoadAssembly(AssemblyLoadInfo assemblyLoadInfo)
{
try
{
if (assemblyLoadInfo.AssemblyName != null)
{
return Assembly.Load(assemblyLoadInfo.AssemblyName);
}
else if (assemblyLoadInfo.IsInlineTask)
{
// Load inline task assemblies from bytes and register the path
return TaskFactoryUtilities.LoadTaskAssembly(assemblyLoadInfo.AssemblyFile);
}
else
{
#if NET && FEATURE_ASSEMBLYLOADCONTEXT
string baseDir = Path.GetDirectoryName(assemblyLoadInfo.AssemblyFile);
s_coreClrAssemblyLoader.AddDependencyLocation(baseDir);
return s_coreClrAssemblyLoader.LoadFromPath(assemblyLoadInfo.AssemblyFile);
#else
return Assembly.UnsafeLoadFrom(assemblyLoadInfo.AssemblyFile);
#endif
}
}
catch (ArgumentException e)
{
// Assembly.Load() and Assembly.LoadFrom() will throw an ArgumentException if the assembly name is invalid
// convert to a FileNotFoundException because it's more meaningful
// NOTE: don't use ErrorUtilities.VerifyThrowFileExists() here because that will hit the disk again
throw new FileNotFoundException(null, assemblyLoadInfo.AssemblyLocation, e);
}
}
private static MetadataLoadContext CreateMetadataLoadContext(AssemblyLoadInfo assemblyLoadInfo)
{
string assemblyFilePath = assemblyLoadInfo.AssemblyFile;
if (string.IsNullOrEmpty(assemblyFilePath) || !File.Exists(assemblyFilePath))
{
throw new FileNotFoundException(null, assemblyLoadInfo.AssemblyLocation);
}
string assemblyDirectory = Path.GetDirectoryName(assemblyFilePath);
string[] dlls = Directory.GetFiles(assemblyDirectory, "*.dll");
string[] exes = Directory.GetFiles(assemblyDirectory, "*.exe");
string[] localAssemblies = [.. dlls, .. exes];
#if !NETFRAMEWORK
// Deduplicate between MSBuild assemblies and task dependencies.
Dictionary<string, string> assembliesDictionary = new(localAssemblies.Length + runtimeAssemblies.Length);
AddAssembliesToDictionary(assembliesDictionary, localAssemblies, runtimeAssemblies);
#else
// Merge all assembly tiers into one dictionary with priority:
// deduplicated CLR2 & CLR3.5 < Local < Runtime (later entries overwrite earlier ones)
Dictionary<string, string> assembliesDictionary = new(localAssemblies.Length + runtimeAssemblies.Length + runtimeAssembliesCLR35_20.Value.Length);
// Add assemblies in priority order (later entries overwrite earlier ones)
AddAssembliesToDictionary(
assembliesDictionary,
runtimeAssembliesCLR35_20.Value,
localAssemblies,
runtimeAssemblies);
#endif
return new MetadataLoadContext(new PathAssemblyResolver(assembliesDictionary.Values));
}
// MetadataLoadContext can expose a PropertyInfo even when resolving PropertyType fails because a
// dependency is absent. Reading the PropertySig blob from the declaring assembly avoids resolving that
// dependency. The result is only an MSBuild expansion surrogate plus a display name for diagnostics; it
// is not the property's executable Type and does not imply that a particular task host supports it.
// A default result means the signature could not be classified safely, although individual supported
// shapes can still return a declared name with no expansion surrogate.
private static (Type TypeForExpansion, string DeclaredTypeName) ReadParameterTypeInfo(PropertyInfo propertyInfo)
{
try
{
#if NET
string assemblyPath = RuntimeFeature.IsDynamicCodeSupported
? propertyInfo.DeclaringType?.Assembly.Location ?? string.Empty
: string.Empty;
#else
string assemblyPath = propertyInfo.DeclaringType?.Assembly.Location ?? string.Empty;
#endif
using FileStream stream = File.OpenRead(assemblyPath);
using var peReader = new PEReader(stream);
MetadataReader metadataReader = peReader.GetMetadataReader();
PropertyDefinition property = metadataReader.GetPropertyDefinition(
(PropertyDefinitionHandle)MetadataTokens.EntityHandle(propertyInfo.MetadataToken));
BlobReader signature = metadataReader.GetBlobReader(property.Signature);
return ReadParameterTypeInfo(ref signature, metadataReader);
}
catch (Exception e) when (!ExceptionHandling.IsCriticalException(e))
{
return default;
}
}
internal static Type ReadParameterTypeForExpansion(ref BlobReader signature, MetadataReader metadataReader) =>
ReadParameterTypeInfo(ref signature, metadataReader).TypeForExpansion;
private static (Type TypeForExpansion, string DeclaredTypeName) ReadParameterTypeInfo(
ref BlobReader signature,
MetadataReader metadataReader)
{
// ECMA-335 II.23.2.5 defines PropertySig as its calling-convention header, a compressed
// parameter count, the property type, and any index parameters. MSBuild task parameters are
// non-generic properties without index parameters; their return type follows the Type grammar
// in II.23.2.12.
SignatureHeader header = signature.ReadSignatureHeader();
if (header.Kind != SignatureKind.Property || header.IsGeneric || signature.ReadCompressedInteger() != 0)
{
return default;
}
(Type TypeForExpansion, string DeclaredTypeName) parameterType =
ReadParameterTypeInfo(ref signature, metadataReader, depth: 0);
// A successful prefix is not enough: trailing bytes would mean an unsupported or malformed shape.
return signature.RemainingBytes == 0 ? parameterType : default;
}
private static (Type TypeForExpansion, string DeclaredTypeName) ReadParameterTypeInfo(
ref BlobReader signature,
MetadataReader metadataReader,
int depth)
{
// Bound Type nesting independently from the declaring-type walk below.
if (depth >= 16)
{
return default;
}
// This is the Type grammar's element-type tag. Class and value-type tags are followed by a
// separately encoded TypeDefOrRef handle, decoded below with ReadTypeHandle.
int typeCode = signature.ReadCompressedInteger();
if (typeCode == (int)SignatureTypeCode.SZArray)
{
// Only one-dimensional, zero-based arrays are expansion surrogates. Nested arrays and the
// multidimensional ARRAY form remain unsupported. Text-converted elements use string[],
// while typed task items retain ITaskItem[] so item identity and metadata survive transport.
(Type TypeForExpansion, string DeclaredTypeName) elementType =
ReadParameterTypeInfo(ref signature, metadataReader, depth + 1);
return (
elementType.TypeForExpansion == typeof(ITaskItem)
? typeof(ITaskItem[])
: elementType.TypeForExpansion?.IsArray == false
? LoadedType.GetArrayExpansionType(elementType.TypeForExpansion)
: null,
elementType.DeclaredTypeName is null ? null : $"{elementType.DeclaredTypeName}[]");
}
if (typeCode is >= (int)SignatureTypeCode.Boolean and <= (int)SignatureTypeCode.String)
{
// MSBuild expands intrinsic scalar values from text; the normal binder or task host performs
// the final conversion to the declared primitive type.
return (typeof(string), $"System.{(SignatureTypeCode)typeCode}");
}
if (metadataReader is not null && typeCode == (int)SignatureTypeCode.GenericTypeInstance)
{
// Per II.23.2.12, GENERICINST is followed by CLASS/VALUETYPE, a TypeDefOrRefEncoded generic
// definition, a compressed argument count, and the argument Types. Only the Framework's
// supported ITaskItem<T>/TaskItem<T> forms can use ordinary ITaskItem transport. Other generic
// forms are rejected; a supported Framework definition with an unsupported argument can still
// retain its declared name for the MSB4069 diagnostic.
int genericTypeKind = signature.ReadCompressedInteger();
if (genericTypeKind is not ((int)SignatureTypeKind.Class) and not ((int)SignatureTypeKind.ValueType))
{
return default;
}
EntityHandle genericTypeHandle = signature.ReadTypeHandle();
string genericTypeName = genericTypeHandle.Kind is HandleKind.TypeDefinition or HandleKind.TypeReference
? GetFullName(genericTypeHandle, depth: 0)
: null;
if (!IsFrameworkTaskItemType(genericTypeHandle, genericTypeName)
|| signature.ReadCompressedInteger() != 1)
{
return default;
}
(Type _, string DeclaredTypeName) argumentType =
ReadParameterTypeInfo(ref signature, metadataReader, depth + 1);
string declaredTypeName = argumentType.DeclaredTypeName is null
? null
: $"{genericTypeName}<{argumentType.DeclaredTypeName}>";
if (!IsSupportedTaskItemValueType(argumentType.DeclaredTypeName))
{
return (null, declaredTypeName);
}
return (typeof(ITaskItem), declaredTypeName);
}
if (metadataReader is null
|| typeCode is not ((int)SignatureTypeKind.Class) and not ((int)SignatureTypeKind.ValueType))
{
return default;
}
// CLASS and VALUETYPE are followed by a TypeDefOrRefEncoded handle. Named path types keep their
// path-aware expansion type; other value types expand from strings. Unsupported reference types
// have no surrogate, but their recoverable declared name is still useful diagnostically.
EntityHandle handle = signature.ReadTypeHandle();
if (handle.Kind is not HandleKind.TypeDefinition and not HandleKind.TypeReference)
{
return default;
}
string fullName = GetFullName(handle, depth: 0);
return (fullName switch
{
string name when name == typeof(AbsolutePath).FullName => typeof(AbsolutePath),
string name when name == typeof(FileInfo).FullName => typeof(FileInfo),
string name when name == typeof(DirectoryInfo).FullName => typeof(DirectoryInfo),
_ when typeCode == (int)SignatureTypeKind.ValueType => typeof(string),
_ => null,
}, fullName);
string GetFullName(EntityHandle typeHandle, int depth)
{
// Bound declaring-type traversal separately from Type nesting. Metadata represents nested
// declarations through their enclosing type; diagnostics use reflection's '+' spelling and
// omit a namespace prefix for global-namespace types.
if (depth >= 16)
{
return null;
}
StringHandle namespaceHandle;
StringHandle nameHandle;
EntityHandle declaringType = default;
if (typeHandle.Kind == HandleKind.TypeDefinition)
{
TypeDefinition type = metadataReader.GetTypeDefinition((TypeDefinitionHandle)typeHandle);
namespaceHandle = type.Namespace;
nameHandle = type.Name;
declaringType = type.GetDeclaringType();
}
else
{
TypeReference type = metadataReader.GetTypeReference((TypeReferenceHandle)typeHandle);
namespaceHandle = type.Namespace;
nameHandle = type.Name;
if (type.ResolutionScope.Kind == HandleKind.TypeReference)
{
declaringType = (TypeReferenceHandle)type.ResolutionScope;
}
}
string name = metadataReader.GetString(nameHandle);
if (!declaringType.IsNil)
{
string declaringTypeName = GetFullName(declaringType, depth + 1);
return declaringTypeName is null ? null : $"{declaringTypeName}+{name}";
}
string @namespace = metadataReader.GetString(namespaceHandle);
return @namespace.Length == 0 ? name : $"{@namespace}.{name}";
}
bool IsFrameworkTaskItemType(EntityHandle typeHandle, string fullName)
{
if (typeHandle.Kind != HandleKind.TypeReference
|| (fullName != typeof(ITaskItem<>).FullName && fullName != typeof(TaskItem<>).FullName))
{
return false;
}
TypeReference typeReference = metadataReader.GetTypeReference((TypeReferenceHandle)typeHandle);
if (typeReference.ResolutionScope.Kind != HandleKind.AssemblyReference)
{
return false;
}
AssemblyReference assemblyReference =
metadataReader.GetAssemblyReference((AssemblyReferenceHandle)typeReference.ResolutionScope);
AssemblyName frameworkAssembly = typeof(ITaskItem).Assembly.GetName();
if (!metadataReader.StringComparer.Equals(assemblyReference.Name, frameworkAssembly.Name))
{
return false;
}
byte[] expectedToken = frameworkAssembly.GetPublicKeyToken();
BlobReader token = metadataReader.GetBlobReader(assemblyReference.PublicKeyOrToken);
return expectedToken is not null
&& token.Length == expectedToken.Length
&& token.ReadBytes(token.Length).SequenceEqual(expectedToken);
}
static bool IsSupportedTaskItemValueType(string fullName)
{
if (fullName is null)
{
return false;
}
Type type = TaskParameterTypeRegistry.TryGetType(fullName)
?? (fullName == typeof(AbsolutePath).FullName ? typeof(AbsolutePath) :
fullName == typeof(FileInfo).FullName ? typeof(FileInfo) :
fullName == typeof(DirectoryInfo).FullName ? typeof(DirectoryInfo) :
null);
return type is not null && ValueTypeParser.IsSupportedType(type);
}
}
/// <summary>
/// Adds assembly paths to a dictionary, keyed by file name.
/// Later arrays in the parameter list take priority over earlier ones,
/// as duplicate file names will overwrite existing entries.
/// </summary>
/// <param name="assembliesDictionary">The dictionary to populate with assembly paths, keyed by file name.</param>
/// <param name="assemblyPathArrays">Arrays of assembly file paths to add, in order of increasing priority.</param>
private static void AddAssembliesToDictionary(Dictionary<string, string> assembliesDictionary, params string[][] assemblyPathArrays)
{
foreach (string[] assemblyPaths in assemblyPathArrays)
{
foreach (string path in assemblyPaths)
{
assembliesDictionary[Path.GetFileName(path)] = path;
}
}
}
/// <summary>
/// Loads the specified type if it exists in the given assembly. If the type name is fully qualified, then a match (if
/// any) is unambiguous; otherwise, if there are multiple types with the same name in different namespaces, the first type
/// found will be returned.
/// </summary>
[RequiresUnreferencedCode("Loads types by reflecting over assemblies discovered at runtime, which is incompatible with trimming.")]
internal LoadedType Load(
string typeName,
AssemblyLoadInfo assembly,
LogWarningDelegate logWarning,
bool useTaskHost = false,
bool taskHostParamsMatchCurrentProc = true)
{
return GetLoadedType(s_cacheOfLoadedTypesByFilter, typeName, assembly, useTaskHost, taskHostParamsMatchCurrentProc, logWarning);
}
/// <summary>
/// Loads the specified type if it exists in the given assembly. If the type name is fully qualified, then a match (if
/// any) is unambiguous; otherwise, if there are multiple types with the same name in different namespaces, the first type
/// found will be returned.
/// </summary>
/// <returns>The loaded type, or null if the type was not found.</returns>
[RequiresUnreferencedCode("Loads types by reflecting over assemblies discovered at runtime, which is incompatible with trimming.")]
internal LoadedType ReflectionOnlyLoad(
string typeName,
AssemblyLoadInfo assembly) => GetLoadedType(s_cacheOfReflectionOnlyLoadedTypesByFilter, typeName, assembly, useTaskHost: false, taskHostParamsMatchCurrentProc: true, logWarning: (format, args) => { });
/// <summary>
/// Loads the specified type if it exists in the given assembly. If the type name is fully qualified, then a match (if
/// any) is unambiguous; otherwise, if there are multiple types with the same name in different namespaces, the first type
/// found will be returned.
/// </summary>
[RequiresUnreferencedCode("Loads types by reflecting over assemblies discovered at runtime, which is incompatible with trimming.")]
private LoadedType GetLoadedType(
ConcurrentDictionary<Type, ConcurrentDictionary<AssemblyLoadInfo, AssemblyInfoToLoadedTypes>> cache,
string typeName,
AssemblyLoadInfo assembly,
bool useTaskHost,
bool taskHostParamsMatchCurrentProc,
LogWarningDelegate logWarning)
{
// A given interface has been used on a number of assemblies. Based on the interface we will get another dictionary which
// will map a specific AssemblyLoadInfo to a AssemblyInfoToLoadedTypes class which knows how to find a typeName in a given assembly.
ConcurrentDictionary<AssemblyLoadInfo, AssemblyInfoToLoadedTypes> loadInfoToType =
cache.GetOrAdd(_desiredInterface, (_) => new ConcurrentDictionary<AssemblyLoadInfo, AssemblyInfoToLoadedTypes>());
// Get an object which is able to take a typename and determine if it is in the assembly pointed to by the AssemblyInfo.
AssemblyInfoToLoadedTypes typeNameToType =
loadInfoToType.GetOrAdd(assembly, (_) => new AssemblyInfoToLoadedTypes(_desiredInterface, _));
return typeNameToType.GetLoadedTypeByTypeName(typeName, useTaskHost, taskHostParamsMatchCurrentProc, logWarning);
}
/// <summary>
/// Given a type filter and an asssemblyInfo object keep track of what types in a given assembly which match the type filter.
/// Also, use this information to determine if a given TypeName is in the assembly which is pointed to by the AssemblyLoadInfo object.
///
/// This type represents a combination of a type filter and an assemblyInfo object.
/// </summary>
[DebuggerDisplay("Types in {_assemblyLoadInfo} matching {_desiredInterface}")]
private class AssemblyInfoToLoadedTypes
{
/// <summary>
/// Lock to prevent two threads from using this object at the same time.
/// Since we fill up internal structures with what is in the assembly
/// </summary>
private readonly LockType _lockObject = new();
/// <summary>
/// The interface that selected types must implement.
/// </summary>
private readonly Type _desiredInterface;
/// <summary>
/// The full name of <see cref="_desiredInterface"/>, cached for the by-name interface lookup.
/// </summary>
private readonly string _desiredInterfaceName;
/// <summary>
/// Assembly load information so we can load an assembly
/// </summary>
private AssemblyLoadInfo _assemblyLoadInfo;
/// <summary>
/// What is the type for the given type name, this may be null if the typeName does not map to a type.
/// </summary>
private ConcurrentDictionary<string, Type> _typeNameToType;
/// <summary>
/// List of public types in the assembly which match the type filter and their corresponding types
/// </summary>
private Dictionary<string, Type> _publicTypeNameToType;
private ConcurrentDictionary<string, LoadedType> _publicTypeNameToLoadedType;
/// <summary>
/// Have we scanned the public types for this assembly yet.
/// </summary>
private long _haveScannedPublicTypes;
/// <summary>
/// Assembly, if any, that we loaded for this type.
/// We use this information to set the LoadedType.LoadedAssembly so that this object can be used
/// to help created AppDomains to resolve those that it could not load successfully
/// </summary>
private Assembly _loadedAssembly;
/// <summary>
/// The architecture requirement of the assembly.
/// </summary>
private string _architecture;
/// <summary>
/// The runtime requirement of the assembly.
/// Detected by examining referenced assemblies for System.Runtime (indicates .NET Core/5+).
/// </summary>
private string _runtime;
/// <summary>
/// Flag to track if we've already attempted to get assembly runtime/architecture.
/// This prevents repeated expensive PE header reads.
/// </summary>
private volatile bool _hasReadRuntimeAndArchitecture;
/// <summary>
/// Given a desired interface, and an assembly to load the type information from determine if a given type name is in the assembly or not.
/// </summary>
internal AssemblyInfoToLoadedTypes(Type desiredInterface, AssemblyLoadInfo loadInfo)
{
ArgumentNullException.ThrowIfNull(desiredInterface);
ArgumentNullException.ThrowIfNull(loadInfo);
_desiredInterface = desiredInterface;
_desiredInterfaceName = desiredInterface.FullName;
_assemblyLoadInfo = loadInfo;
_typeNameToType = new(StringComparer.OrdinalIgnoreCase);
_publicTypeNameToType = new Dictionary<string, Type>(StringComparer.OrdinalIgnoreCase);
_publicTypeNameToLoadedType = new(StringComparer.OrdinalIgnoreCase);
}
/// <summary>
/// Determines whether <paramref name="type"/> is a concrete, public class that implements the desired interface.
/// </summary>
/// <remarks>
/// The interface is matched by name rather than with <c>typeof(...).IsAssignableFrom</c> because the candidate
/// type may have been inspected through a <see cref="MetadataLoadContext"/>, whose reflection universe is
/// separate from the running one (so <c>IsAssignableFrom</c> would always be false). The
/// <see cref="Type.GetInterface(string)"/> call is trim-unsafe, but this method is only reachable from the
/// [RequiresUnreferencedCode] load paths, which load task and logger assemblies discovered at runtime.
/// </remarks>
[RequiresUnreferencedCode("Matches a runtime-discovered type against the desired interface by reflecting over its interface list, which is incompatible with trimming.")]
private bool IsDesiredType(Type type) =>
type.IsClass && !type.IsAbstract && type.GetInterface(_desiredInterfaceName) is not null;
/// <summary>
/// Determine if a given type name is in the assembly or not. Return null if the type is not in the assembly.
/// </summary>
[RequiresUnreferencedCode("Loads types by reflecting over assemblies discovered at runtime, which is incompatible with trimming.")]
internal LoadedType GetLoadedTypeByTypeName(
string typeName,
bool useTaskHost,
bool taskHostParamsMatchCurrentProc,
LogWarningDelegate logWarning)
{
ArgumentNullException.ThrowIfNull(typeName);
if (ShouldUseMetadataLoadContext(useTaskHost, taskHostParamsMatchCurrentProc))
{
return GetTypeForOutOfProcExecution(typeName);
}
LoadedType loadedType;
try
{
loadedType = LoadInProc(typeName);
}
catch
{
// The assembly can't be loaded in-proc due to architecture or runtime mismatch that was discovered during in-proc load.
// Fall back to metadata load context. It will prepare prerequisites for out of proc execution.
MSBuildEventSource.Log.FallbackAssemblyLoadStart(typeName);
loadedType = GetTypeForOutOfProcExecution(typeName);
logWarning("AssemblyLoad_Warning", loadedType?.LoadedAssemblyName?.Name);
MSBuildEventSource.Log.FallbackAssemblyLoadStop(typeName);
}
return loadedType;
}
/// <summary>
/// Normal in-proc loading path.
/// Only one thread should be doing operations on this instance of the object at a time
/// This loads the assembly for actual execution (not metadata-only).
/// </summary>
/// <param name="typeName">The type to be loaded.</param>
[RequiresUnreferencedCode("Loads types by reflecting over assemblies discovered at runtime, which is incompatible with trimming.")]
private LoadedType LoadInProc(string typeName)
{
Type type = _typeNameToType.GetOrAdd(typeName, (key) =>
{
if ((_assemblyLoadInfo.AssemblyName != null) && (typeName.Length > 0))
{
try
{
// try to load the type using its assembly qualified name
Type t2 = Type.GetType(typeName + "," + _assemblyLoadInfo.AssemblyName, false /* don't throw on error */, true /* case-insensitive */);
if (t2 != null)
{
return !IsDesiredType(t2) ? null : t2;
}
}
catch (ArgumentException)
{
// Type.GetType() will throw this exception if the type name is invalid -- but we have no idea if it's the
// type or the assembly name that's the problem -- so just ignore the exception, because we're going to
// check the existence/validity of the assembly and type respectively, below anyway
}
}
if (Interlocked.Read(ref _haveScannedPublicTypes) == 0)
{
lock (_lockObject)
{
if (Interlocked.Read(ref _haveScannedPublicTypes) == 0)
{
ScanAssemblyForPublicTypes();
Interlocked.Exchange(ref _haveScannedPublicTypes, ~0);
}
}
}
foreach (KeyValuePair<string, Type> desiredTypeInAssembly in _publicTypeNameToType)
{
// if type matches partially on its name
if (typeName.Length == 0 || IsPartialTypeNameMatch(desiredTypeInAssembly.Key, typeName))
{
return desiredTypeInAssembly.Value;
}
}
return null;
});
return type != null
? LoadedType.CreateWithParameterTypeInfoResolver(
type,
_assemblyLoadInfo,
_loadedAssembly ?? type.Assembly,
typeof(ITaskItem),
runtime: null,
architecture: null,
loadedViaMetadataLoadContext: false,
parameterTypeInfoResolver: ReadParameterTypeInfo)
: null;
}
/// <summary>
/// Determine whether an assembly is likely to be used out of process and thus loaded with a <see cref="MetadataLoadContext"/>.
/// </summary>
/// <param name="useTaskHost">Task Host Parameter was specified explicitly in XML or through environment variable.</param>
/// <param name="taskHostParamsMatchCurrentProc">The parameter defines if Runtime/Architecture explicitly defined in XML match current process.</param>
private bool ShouldUseMetadataLoadContext(bool useTaskHost, bool taskHostParamsMatchCurrentProc) =>
(useTaskHost || !taskHostParamsMatchCurrentProc) && _assemblyLoadInfo.AssemblyFile is not null;
[RequiresUnreferencedCode("Loads types by reflecting over assemblies discovered at runtime, which is incompatible with trimming.")]
private LoadedType GetTypeForOutOfProcExecution(string typeName) => _publicTypeNameToLoadedType
.GetOrAdd(typeName, typeName =>
{
MSBuildEventSource.Log.LoadAssemblyAndFindTypeStart();
using MetadataLoadContext context = CreateMetadataLoadContext(_assemblyLoadInfo);
Assembly loadedAssembly = context.LoadFromAssemblyPath(_assemblyLoadInfo.AssemblyFile);
SetArchitectureAndRuntime(loadedAssembly);
Type foundType = null;
int numberOfTypesSearched = 0;
// Try direct type lookup first (fastest)
if (!string.IsNullOrEmpty(typeName))
{
foundType = loadedAssembly.GetType(typeName, throwOnError: false);
if (foundType != null && foundType.IsPublic && IsDesiredType(foundType))
{
numberOfTypesSearched = 1;
}
}
// Fallback: enumerate all types for partial matching
if (foundType == null)
{
foreach (Type publicType in loadedAssembly.GetExportedTypes())
{
numberOfTypesSearched++;
try
{
if (IsDesiredType(publicType) && (typeName.Length == 0 || IsPartialTypeNameMatch(publicType.FullName, typeName)))
{
foundType = publicType;
break;
}
}
catch
{
// Ignore types that can't be loaded/reflected upon.
// These types might be needed out of proc and be resolved there.
}
}
}
if (foundType != null)
{
MSBuildEventSource.Log.CreateLoadedTypeStart(loadedAssembly.FullName);
var taskItemType = context.LoadFromAssemblyPath(microsoftBuildFrameworkPath).GetType(typeof(ITaskItem).FullName);
LoadedType loadedType = LoadedType.CreateWithParameterTypeInfoResolver(
foundType,
_assemblyLoadInfo,
loadedAssembly,
taskItemType,
_runtime,
_architecture,
loadedViaMetadataLoadContext: true,
parameterTypeInfoResolver: ReadParameterTypeInfo);
MSBuildEventSource.Log.CreateLoadedTypeStop(loadedAssembly.FullName);
return loadedType;
}
MSBuildEventSource.Log.LoadAssemblyAndFindTypeStop(_assemblyLoadInfo.AssemblyFile, numberOfTypesSearched);
return null;
});
/// <summary>
/// Gets architecture and runtime from the assembly using MetadataLoadContext.
/// </summary>
[RequiresUnreferencedCode("Reflects over a runtime-loaded assembly to determine its target runtime and architecture, which is incompatible with trimming.")]
private void SetArchitectureAndRuntime(Assembly assembly)
{
if (_hasReadRuntimeAndArchitecture)
{
return;
}
try
{
SetRuntime();
SetArchitecture();
_hasReadRuntimeAndArchitecture = true;
}
catch
{
// If we fail to read the assembly for any reason don't throw, just reset the values.
_architecture = null;
_runtime = null;
_hasReadRuntimeAndArchitecture = false;
}
void SetRuntime()
{
string targetFramework = null;
try
{
CustomAttributeData targetFrameworkAttr = assembly?
.GetCustomAttributesData()?
.FirstOrDefault(a => a.AttributeType.Name == TargetFrameworkAttributeName && a.AttributeType.Namespace == VersioningNamespaceName);
if (targetFrameworkAttr != null && targetFrameworkAttr.ConstructorArguments.Count > 0)
{
// the final value looks like: ".NETFramework,Version=v3.5"
targetFramework = targetFrameworkAttr.ConstructorArguments[0].Value as string ?? string.Empty;
_runtime = targetFramework.StartsWith(DotNetCoreIdentifier, StringComparison.Ordinal) ? MSBuildRuntimeValues.net : MSBuildRuntimeValues.clr4;
}
}
catch
{
// something went wrong with reading the custom attribute!
}
if (targetFramework == null && _runtime == null)
{
bool hasSystemRuntime = assembly.GetReferencedAssemblies().Any(a => string.Equals(a.Name, SystemRuntimeAssemblyName, StringComparison.OrdinalIgnoreCase));
if (hasSystemRuntime)
{
_runtime = MSBuildRuntimeValues.net;
}
}
}
void SetArchitecture()
{
Module module = assembly?.Modules?.FirstOrDefault();
if (module == null)
{
return;
}
module.GetPEKind(out PortableExecutableKinds peKind, out ImageFileMachine machine);
bool isILOnly = (peKind & PortableExecutableKinds.ILOnly) != 0;
bool requires32Bit = (peKind & PortableExecutableKinds.Required32Bit) != 0;
bool prefers32Bit = (peKind & PortableExecutableKinds.Preferred32Bit) != 0;
if (requires32Bit || prefers32Bit)
{
_architecture = MSBuildArchitectureValues.x86;
return;
}
if (isILOnly && machine == ImageFileMachine.I386)
{
_architecture = MSBuildArchitectureValues.any;
return;
}
_architecture = machine switch
{
ImageFileMachine.I386 => MSBuildArchitectureValues.x86,
ImageFileMachine.AMD64 => MSBuildArchitectureValues.x64,
(ImageFileMachine)0xAA64 => MSBuildArchitectureValues.arm64,
_ => MSBuildArchitectureValues.any,
};
}
}
/// <summary>
/// Scan the assembly pointed to by the assemblyLoadInfo for public types. We will use these public types to do partial name matching on
/// to find tasks, loggers, and task factories.
/// </summary>
[RequiresUnreferencedCode("Loads and reflects over a runtime-discovered assembly's public types, which is incompatible with trimming.")]
private void ScanAssemblyForPublicTypes()
{
// we need to search the assembly for the type...
_loadedAssembly = LoadAssembly(_assemblyLoadInfo);
// only look at public types
Type[] allPublicTypesInAssembly = _loadedAssembly.GetExportedTypes();
foreach (Type publicType in allPublicTypesInAssembly)
{
if (IsDesiredType(publicType))
{
_publicTypeNameToType.Add(publicType.FullName, publicType);
}
}
}
}
}