public static void TryAdd_ConditionallyAdds()
{
var cwt = new ConditionalWeakTable <object, object>();
object value1 = new object();
object value2 = new object();
object found;
object key1 = new object();
Assert.True(cwt.TryAdd(key1, value1));
Assert.False(cwt.TryAdd(key1, value2));
Assert.True(cwt.TryGetValue(key1, out found));
Assert.Same(value1, found);
Assert.Equal(1, cwt.Count());
object key2 = new object();
Assert.True(cwt.TryAdd(key2, value1));
Assert.False(cwt.TryAdd(key2, value2));
Assert.True(cwt.TryGetValue(key2, out found));
Assert.Same(value1, found);
Assert.Equal(2, cwt.Count());
GC.KeepAlive(key1);
GC.KeepAlive(key2);
}
/// <summary>
/// Returns the portable PDB reader for the assembly path
/// </summary>
/// <param name="assembly">Managed Assembly to be used as a cache key</param>
/// <param name="assemblyPath">
/// File path of the assembly or null if the module is dynamic (generated by Reflection.Emit).
/// </param>
/// <param name="loadedPeAddress">
/// Loaded PE image address or zero if the module is dynamic (generated by Reflection.Emit).
/// Dynamic modules have their PDBs (if any) generated to an in-memory stream
/// (pointed to by <paramref name="inMemoryPdbAddress"/> and <paramref name="inMemoryPdbSize"/>).
/// </param>
/// <param name="loadedPeSize">loaded PE image size</param>
/// <param name="isFileLayout">if true, the PE image is file layout, false it is loaded layout</param>
/// <param name="inMemoryPdbAddress">in memory PDB address or zero</param>
/// <param name="inMemoryPdbSize">in memory PDB size</param>
/// <returns>reader</returns>
/// <remarks>
/// Accounts for unloadable and dynamic types by keying the cache on the managed Assembly. The
/// underlying ConditionalWeakTable doesn't keep the assembly alive, so cached types will be
/// correctly invalidated when the Assembly is unloaded by the GC.
/// </remarks>
private unsafe MetadataReader?TryGetReader(Assembly assembly, string assemblyPath, IntPtr loadedPeAddress, int loadedPeSize, bool isFileLayout, IntPtr inMemoryPdbAddress, int inMemoryPdbSize)
{
if ((loadedPeAddress == IntPtr.Zero || assemblyPath == null) && inMemoryPdbAddress == IntPtr.Zero)
{
// Dynamic or in-memory module without symbols (they would be in-memory if they were available).
return(null);
}
MetadataReaderProvider?provider;
while (!_metadataCache.TryGetValue(assembly, out provider))
{
provider = inMemoryPdbAddress != IntPtr.Zero ?
TryOpenReaderForInMemoryPdb(inMemoryPdbAddress, inMemoryPdbSize) :
TryOpenReaderFromAssemblyFile(assemblyPath !, loadedPeAddress, loadedPeSize, isFileLayout);
if (_metadataCache.TryAdd(assembly, provider))
{
break;
}
provider?.Dispose();
}
// The reader has already been open, so this doesn't throw.
return(provider?.GetMetadataReader());
}
public static void Add(int numObjects, bool tryAdd)
{
// Isolated to ensure we drop all references even in debug builds where lifetime is extended by the JIT to the end of the method
Func <int, Tuple <ConditionalWeakTable <object, object>, WeakReference[], WeakReference[]> > body = count =>
{
object[] keys = Enumerable.Range(0, count).Select(_ => new object()).ToArray();
object[] values = Enumerable.Range(0, count).Select(_ => new object()).ToArray();
var cwt = new ConditionalWeakTable <object, object>();
for (int i = 0; i < count; i++)
{
if (tryAdd)
{
Assert.True(cwt.TryAdd(keys[i], values[i]));
}
else
{
cwt.Add(keys[i], values[i]);
}
}
for (int i = 0; i < count; i++)
{
object value;
Assert.True(cwt.TryGetValue(keys[i], out value));
Assert.Same(values[i], value);
Assert.Same(value, cwt.GetOrCreateValue(keys[i]));
Assert.Same(value, cwt.GetValue(keys[i], _ => new object()));
}
return(Tuple.Create(cwt, keys.Select(k => new WeakReference(k)).ToArray(), values.Select(v => new WeakReference(v)).ToArray()));
};
Tuple <ConditionalWeakTable <object, object>, WeakReference[], WeakReference[]> result = body(numObjects);
GC.Collect();
Assert.NotNull(result.Item1);
for (int i = 0; i < numObjects; i++)
{
Assert.False(result.Item2[i].IsAlive, $"Expected not to find key #{i}");
Assert.False(result.Item3[i].IsAlive, $"Expected not to find value #{i}");
}
}
/// <summary>
/// Set a callback for resolving native library imports from an assembly.
/// This per-assembly resolver is the first attempt to resolve native library loads
/// initiated by this assembly.
///
/// Only one resolver can be registered per assembly.
/// Trying to register a second resolver fails with InvalidOperationException.
/// </summary>
/// <param name="assembly">The assembly for which the resolver is registered</param>
/// <param name="resolver">The resolver callback to register</param>
/// <exception cref="System.ArgumentNullException">If assembly or resolver is null</exception>
/// <exception cref="System.ArgumentException">If a resolver is already set for this assembly</exception>
public static void SetDllImportResolver(Assembly assembly, DllImportResolver resolver)
{
ArgumentNullException.ThrowIfNull(assembly);
ArgumentNullException.ThrowIfNull(resolver);
if (assembly is not RuntimeAssembly)
{
throw new ArgumentException(SR.Argument_MustBeRuntimeAssembly);
}
if (s_nativeDllResolveMap == null)
{
Interlocked.CompareExchange(ref s_nativeDllResolveMap,
new ConditionalWeakTable <Assembly, DllImportResolver>(), null);
}
if (!s_nativeDllResolveMap.TryAdd(assembly, resolver))
{
throw new InvalidOperationException(SR.InvalidOperation_CannotRegisterSecondResolver);
}
}
