|
//---------------------------------------------------------------------
// <copyright file="MetadataAssemblyHelper.cs" company="Microsoft">
// Copyright (c) Microsoft Corporation. All rights reserved.
// </copyright>
//
// @owner Microsoft
// @backupOwner Microsoft
//---------------------------------------------------------------------
using System.Reflection;
using System.Collections.Generic;
using System.Diagnostics;
using System.Data.Common.Utils;
namespace System.Data.Metadata.Edm
{
internal static class MetadataAssemblyHelper
{
static byte [] EcmaPublicKeyToken = System.Data.EntityModel.SchemaObjectModel.ScalarType.ConvertToByteArray(AssemblyRef.EcmaPublicKey);
static byte [] MsPublicKeyToken = System.Data.EntityModel.SchemaObjectModel.ScalarType.ConvertToByteArray(AssemblyRef.MicrosoftPublicKey);
private static Memoizer<Assembly, bool> _filterAssemblyCacheByAssembly = new Memoizer<Assembly, bool>(MetadataAssemblyHelper.ComputeShouldFilterAssembly, EqualityComparer<Assembly>.Default);
internal static Assembly SafeLoadReferencedAssembly(AssemblyName assemblyName)
{
Assembly assembly = null;
try
{
assembly = Assembly.Load(assemblyName);
}
catch (System.IO.FileNotFoundException)
{
// See 552932: ObjectItemCollection: fails on referenced assemblies that are not available
}
return assembly;
}
private static bool ComputeShouldFilterAssembly(Assembly assembly)
{
AssemblyName assemblyName = new AssemblyName(assembly.FullName);
return ShouldFilterAssembly(assemblyName);
}
internal static bool ShouldFilterAssembly(Assembly assembly)
{
return _filterAssemblyCacheByAssembly.Evaluate(assembly);
}
/// <summary>Is the assembly and its referened assemblies not expected to have any metadata</summary>
private static bool ShouldFilterAssembly(AssemblyName assemblyName)
{
return (ArePublicKeyTokensEqual(assemblyName.GetPublicKeyToken(), EcmaPublicKeyToken) ||
ArePublicKeyTokensEqual(assemblyName.GetPublicKeyToken(), MsPublicKeyToken));
}
private static bool ArePublicKeyTokensEqual(byte [] left, byte [] right)
{
// some assemblies don't have public keys
if (left.Length != right.Length)
{
return false;
}
for (int i = 0; i < left.Length; i++)
{
if (left[i] != right[i])
{
return false;
}
}
return true;
}
internal static IEnumerable<Assembly> GetNonSystemReferencedAssemblies(Assembly assembly)
{
foreach (AssemblyName name in assembly.GetReferencedAssemblies())
{
if (!ShouldFilterAssembly(name))
{
Assembly referenceAssembly = SafeLoadReferencedAssembly(name);
if(referenceAssembly != null )
{
yield return referenceAssembly;
}
}
}
}
}
}
|