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Streamlines TypeFinder with better lock and an error check on app_cod…
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…e which could otherwise bring down the app
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@Shazwazza
Shazwazza committed Sep 25, 2015
1 parent b384f1b commit 407cd0c
Showing 1 changed file with 81 additions and 146 deletions.
227 changes: 81 additions & 146 deletions src/Umbraco.Core/TypeFinder.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -26,11 +26,8 @@ namespace Umbraco.Core
/// </summary>
public static class TypeFinder
{
private static readonly HashSet<Assembly> LocalFilteredAssemblyCache = new HashSet<Assembly>();
private static readonly ReaderWriterLockSlim LocalFilteredAssemblyCacheLocker = new ReaderWriterLockSlim();
private static HashSet<Assembly> _allAssemblies = null;
private static HashSet<Assembly> _binFolderAssemblies = null;
private static readonly ReaderWriterLockSlim Locker = new ReaderWriterLockSlim();
private static volatile HashSet<Assembly> _localFilteredAssemblyCache = null;
private static readonly object LocalFilteredAssemblyCacheLocker = new object();

/// <summary>
/// lazily load a reference to all assemblies and only local assemblies.
Expand All @@ -46,162 +43,97 @@ public static class TypeFinder
/// </remarks>
internal static HashSet<Assembly> GetAllAssemblies()
{
using (var lck = new UpgradeableReadLock(Locker))
{
if (_allAssemblies == null)
{
return AllAssemblies.Value;
}

lck.UpgradeToWriteLock();
//Lazy access to the all assemblies list
private static readonly Lazy<HashSet<Assembly>> AllAssemblies = new Lazy<HashSet<Assembly>>(() =>
{
HashSet<Assembly> assemblies = null;
try
{
var isHosted = HttpContext.Current != null;

HashSet<Assembly> assemblies = null;
try
try
{
if (isHosted)
{
var isHosted = HttpContext.Current != null;
assemblies = new HashSet<Assembly>(BuildManager.GetReferencedAssemblies().Cast<Assembly>());
}
}
catch (InvalidOperationException e)
{
if (!(e.InnerException is SecurityException))
throw;
}

if (assemblies == null)
{
//NOTE: we cannot use AppDomain.CurrentDomain.GetAssemblies() because this only returns assemblies that have
// already been loaded in to the app domain, instead we will look directly into the bin folder and load each one.
var binFolder = IOHelper.GetRootDirectoryBinFolder();
var binAssemblyFiles = Directory.GetFiles(binFolder, "*.dll", SearchOption.TopDirectoryOnly).ToList();
//var binFolder = Assembly.GetExecutingAssembly().GetAssemblyFile().Directory;
//var binAssemblyFiles = Directory.GetFiles(binFolder.FullName, "*.dll", SearchOption.TopDirectoryOnly).ToList();
assemblies = new HashSet<Assembly>();
foreach (var a in binAssemblyFiles)
{
try
{
if (isHosted)
{
assemblies = new HashSet<Assembly>(BuildManager.GetReferencedAssemblies().Cast<Assembly>());
}
}
catch (InvalidOperationException e)
{
if (!(e.InnerException is SecurityException))
throw;
var assName = AssemblyName.GetAssemblyName(a);
var ass = Assembly.Load(assName);
assemblies.Add(ass);
}


if (assemblies == null)
catch (Exception e)
{
//NOTE: we cannot use AppDomain.CurrentDomain.GetAssemblies() because this only returns assemblies that have
// already been loaded in to the app domain, instead we will look directly into the bin folder and load each one.
var binFolder = IOHelper.GetRootDirectoryBinFolder();
var binAssemblyFiles = Directory.GetFiles(binFolder, "*.dll", SearchOption.TopDirectoryOnly).ToList();
//var binFolder = Assembly.GetExecutingAssembly().GetAssemblyFile().Directory;
//var binAssemblyFiles = Directory.GetFiles(binFolder.FullName, "*.dll", SearchOption.TopDirectoryOnly).ToList();
assemblies = new HashSet<Assembly>();
foreach (var a in binAssemblyFiles)
if (e is SecurityException || e is BadImageFormatException)
{
try
{
var assName = AssemblyName.GetAssemblyName(a);
var ass = Assembly.Load(assName);
assemblies.Add(ass);
}
catch (Exception e)
{
if (e is SecurityException || e is BadImageFormatException)
{
//swallow these exceptions
}
else
{
throw;
}
}
//swallow these exceptions
}
}

//if for some reason they are still no assemblies, then use the AppDomain to load in already loaded assemblies.
if (!assemblies.Any())
{
foreach (var a in AppDomain.CurrentDomain.GetAssemblies())
else
{
assemblies.Add(a);
throw;
}
}

//here we are trying to get the App_Code assembly
var fileExtensions = new[] { ".cs", ".vb" }; //only vb and cs files are supported
var appCodeFolder = new DirectoryInfo(IOHelper.MapPath(IOHelper.ResolveUrl("~/App_code")));
//check if the folder exists and if there are any files in it with the supported file extensions
if (appCodeFolder.Exists && (fileExtensions.Any(x => appCodeFolder.GetFiles("*" + x).Any())))
{
var appCodeAssembly = Assembly.Load("App_Code");
if (!assemblies.Contains(appCodeAssembly)) // BuildManager will find App_Code already
assemblies.Add(appCodeAssembly);
}

//now set the _allAssemblies
_allAssemblies = new HashSet<Assembly>(assemblies);

}
catch (InvalidOperationException e)
{
if (!(e.InnerException is SecurityException))
throw;
}

_binFolderAssemblies = _allAssemblies;
//if for some reason they are still no assemblies, then use the AppDomain to load in already loaded assemblies.
if (!assemblies.Any())
{
foreach (var a in AppDomain.CurrentDomain.GetAssemblies())
{
assemblies.Add(a);
}
}

return _allAssemblies;
}
}

/// <summary>
/// Returns only assemblies found in the bin folder that have been loaded into the app domain.
/// </summary>
/// <returns></returns>
/// <remarks>
/// This will be used if we implement App_Plugins from Umbraco v5 but currently it is not used.
/// </remarks>
internal static HashSet<Assembly> GetBinAssemblies()
{

if (_binFolderAssemblies == null)
{
using (new WriteLock(Locker))
//here we are trying to get the App_Code assembly
var fileExtensions = new[] { ".cs", ".vb" }; //only vb and cs files are supported
var appCodeFolder = new DirectoryInfo(IOHelper.MapPath(IOHelper.ResolveUrl("~/App_code")));
//check if the folder exists and if there are any files in it with the supported file extensions
if (appCodeFolder.Exists && (fileExtensions.Any(x => appCodeFolder.GetFiles("*" + x).Any())))
{
var assemblies = GetAssembliesWithKnownExclusions().ToArray();
var binFolder = Assembly.GetExecutingAssembly().GetAssemblyFile().Directory;
var binAssemblyFiles = Directory.GetFiles(binFolder.FullName, "*.dll", SearchOption.TopDirectoryOnly).ToList();
var domainAssemblyNames = binAssemblyFiles.Select(AssemblyName.GetAssemblyName);
var safeDomainAssemblies = new HashSet<Assembly>();
var binFolderAssemblies = new HashSet<Assembly>();

foreach (var a in assemblies)
try
{
try
{
//do a test to see if its queryable in med trust
var assemblyFile = a.GetAssemblyFile();
safeDomainAssemblies.Add(a);
}
catch (SecurityException)
{
//we will just ignore this because this will fail
//in medium trust for system assemblies, we get an exception but we just want to continue until we get to
//an assembly that is ok.
}
var appCodeAssembly = Assembly.Load("App_Code");
if (!assemblies.Contains(appCodeAssembly)) // BuildManager will find App_Code already
assemblies.Add(appCodeAssembly);
}

foreach (var assemblyName in domainAssemblyNames)
catch (FileNotFoundException ex)
{
try
{
var foundAssembly =
safeDomainAssemblies.FirstOrDefault(a => a.GetAssemblyFile() == assemblyName.GetAssemblyFile());
if (foundAssembly != null)
{
binFolderAssemblies.Add(foundAssembly);
}
}
catch (SecurityException)
{
//we will just ignore this because if we are trying to do a call to:
// AssemblyName.ReferenceMatchesDefinition(a.GetName(), assemblyName)))
//in medium trust for system assemblies, we get an exception but we just want to continue until we get to
//an assembly that is ok.
}
//this will occur if it cannot load the assembly
LogHelper.Error(typeof(TypeFinder), "Could not load assembly App_Code", ex);
}

_binFolderAssemblies = new HashSet<Assembly>(binFolderAssemblies);
}
}
return _binFolderAssemblies;
}
catch (InvalidOperationException e)
{
if (!(e.InnerException is SecurityException))
throw;
}

return assemblies;
});

/// <summary>
/// Return a list of found local Assemblies excluding the known assemblies we don't want to scan
Expand All @@ -213,20 +145,23 @@ internal static HashSet<Assembly> GetBinAssemblies()
internal static HashSet<Assembly> GetAssembliesWithKnownExclusions(
IEnumerable<Assembly> excludeFromResults = null)
{
using (var lck = new UpgradeableReadLock(LocalFilteredAssemblyCacheLocker))
if (_localFilteredAssemblyCache == null)
{
if (LocalFilteredAssemblyCache.Any()) return LocalFilteredAssemblyCache;

lck.UpgradeToWriteLock();

var assemblies = GetFilteredAssemblies(excludeFromResults, KnownAssemblyExclusionFilter);
foreach (var a in assemblies)
lock (LocalFilteredAssemblyCacheLocker)
{
LocalFilteredAssemblyCache.Add(a);
//double check
if (_localFilteredAssemblyCache == null)
{
_localFilteredAssemblyCache = new HashSet<Assembly>();
var assemblies = GetFilteredAssemblies(excludeFromResults, KnownAssemblyExclusionFilter);
foreach (var a in assemblies)
{
_localFilteredAssemblyCache.Add(a);
}
}
}

return LocalFilteredAssemblyCache;
}
return _localFilteredAssemblyCache;
}

/// <summary>
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