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//------------------------------------------------------------------------------
// <copyright file="AssemblyCache.cs" company="Microsoft">
// Copyright (c) Microsoft Corporation. All rights reserved.
// </copyright>
//------------------------------------------------------------------------------
namespace System.Web.UI {
using System;
using System.Collections;
using System.Collections.Concurrent;
using System.Collections.Generic;
using System.Diagnostics;
using System.Diagnostics.CodeAnalysis;
using System.Reflection;
using System.Web.Configuration;
using System.Web.Script;
// Caches Assembly APIs to improve performance
internal static class AssemblyCache {
// PERF: Cache reference to System.Web.Extensions assembly. Use ScriptManager since it's guaranteed to be in S.W.E
public static readonly Assembly SystemWebExtensions = typeof(ScriptManager).Assembly;
public static readonly Assembly SystemWeb = typeof(Page).Assembly;
private static CompilationSection _compilationSection;
internal static bool _useCompilationSection = true;
// Maps string (assembly name) to Assembly
private static readonly Hashtable _assemblyCache = Hashtable.Synchronized(new Hashtable());
// Maps assembly to Version
// internal so it can be manipulated by the unit test suite
internal static readonly Hashtable _versionCache = Hashtable.Synchronized(new Hashtable());
// Maps an assembly to its ajax framework assembly attribute. If it doesn't have one, it maps it to a null value
private static readonly ConcurrentDictionary<Assembly, AjaxFrameworkAssemblyAttribute> _ajaxAssemblyAttributeCache =
new ConcurrentDictionary<Assembly, AjaxFrameworkAssemblyAttribute>();
private static CompilationSection CompilationSection {
get {
if (_compilationSection == null) {
_compilationSection = RuntimeConfig.GetAppConfig().Compilation;
}
return _compilationSection;
}
}
public static Version GetVersion(Assembly assembly) {
Debug.Assert(assembly != null);
Version version = (Version)_versionCache[assembly];
if (version == null) {
// use new AssemblyName() instead of assembly.GetName() so it works in medium trust
version = new AssemblyName(assembly.FullName).Version;
_versionCache[assembly] = version;
}
return version;
}
public static Assembly Load(string assemblyName) {
Debug.Assert(!String.IsNullOrEmpty(assemblyName));
Assembly assembly = (Assembly)_assemblyCache[assemblyName];
if (assembly == null) {
// _useCompilationSection must be set to false in a unit test environment since there
// is no http runtime, and therefore no trust level is set.
if (_useCompilationSection) {
assembly = CompilationSection.LoadAssembly(assemblyName, true);
}
else {
assembly = Assembly.Load(assemblyName);
}
_assemblyCache[assemblyName] = assembly;
}
return assembly;
}
public static bool IsAjaxFrameworkAssembly(Assembly assembly) {
return (GetAjaxFrameworkAssemblyAttribute(assembly) != null);
}
public static AjaxFrameworkAssemblyAttribute GetAjaxFrameworkAssemblyAttribute(Assembly assembly) {
Debug.Assert(assembly != null);
AjaxFrameworkAssemblyAttribute ajaxFrameworkAssemblyAttribute;
if (!_ajaxAssemblyAttributeCache.TryGetValue(assembly, out ajaxFrameworkAssemblyAttribute)) {
ajaxFrameworkAssemblyAttribute = SafeGetAjaxFrameworkAssemblyAttribute(assembly);
_ajaxAssemblyAttributeCache.TryAdd(assembly, ajaxFrameworkAssemblyAttribute);
}
return ajaxFrameworkAssemblyAttribute;
}
[SuppressMessage("Microsoft.Design", "CA1031:DoNotCatchGeneralExceptionTypes", Justification = "We do not want to throw from this method.")]
internal static AjaxFrameworkAssemblyAttribute SafeGetAjaxFrameworkAssemblyAttribute(ICustomAttributeProvider attributeProvider) {
try {
foreach (Attribute attribute in attributeProvider.GetCustomAttributes(inherit: false)) {
AjaxFrameworkAssemblyAttribute ajaxFrameworkAttribute = attribute as AjaxFrameworkAssemblyAttribute;
if (ajaxFrameworkAttribute != null) {
return ajaxFrameworkAttribute;
}
}
}
catch {
// Bug 34311: If we are unable to load the attribute, don't throw.
}
return null;
}
}
}
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