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// ==++==
//
// Copyright (c) Microsoft Corporation. All rights reserved.
//
// ==--==
// =+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+
//
// AggregateException.cs
//
// <OWNER>Microsoft</OWNER>
//
// Public type to communicate multiple failures to an end-user.
//
// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Diagnostics;
using System.Globalization;
using System.Runtime.ExceptionServices;
using System.Runtime.Serialization;
using System.Security;
using System.Threading;
namespace System
{
/// <summary>Represents one or more errors that occur during application execution.</summary>
/// <remarks>
/// <see cref="AggregateException"/> is used to consolidate multiple failures into a single, throwable
/// exception object.
/// </remarks>
[Serializable]
[DebuggerDisplay("Count = {InnerExceptionCount}")]
public class AggregateException : Exception
{
private ReadOnlyCollection<Exception> m_innerExceptions; // Complete set of exceptions.
/// <summary>
/// Initializes a new instance of the <see cref="AggregateException"/> class.
/// </summary>
public AggregateException()
: base(Environment.GetResourceString("AggregateException_ctor_DefaultMessage"))
{
m_innerExceptions = new ReadOnlyCollection<Exception>(new Exception[0]);
}
/// <summary>
/// Initializes a new instance of the <see cref="AggregateException"/> class with
/// a specified error message.
/// </summary>
/// <param name="message">The error message that explains the reason for the exception.</param>
public AggregateException(string message)
: base(message)
{
m_innerExceptions = new ReadOnlyCollection<Exception>(new Exception[0]);
}
/// <summary>
/// Initializes a new instance of the <see cref="AggregateException"/> class with a specified error
/// message and a reference to the inner exception that is the cause of this exception.
/// </summary>
/// <param name="message">The error message that explains the reason for the exception.</param>
/// <param name="innerException">The exception that is the cause of the current exception.</param>
/// <exception cref="T:System.ArgumentNullException">The <paramref name="innerException"/> argument
/// is null.</exception>
public AggregateException(string message, Exception innerException)
: base(message, innerException)
{
if (innerException == null)
{
throw new ArgumentNullException("innerException");
}
m_innerExceptions = new ReadOnlyCollection<Exception>(new Exception[] { innerException });
}
/// <summary>
/// Initializes a new instance of the <see cref="AggregateException"/> class with
/// references to the inner exceptions that are the cause of this exception.
/// </summary>
/// <param name="innerExceptions">The exceptions that are the cause of the current exception.</param>
/// <exception cref="T:System.ArgumentNullException">The <paramref name="innerExceptions"/> argument
/// is null.</exception>
/// <exception cref="T:System.ArgumentException">An element of <paramref name="innerExceptions"/> is
/// null.</exception>
public AggregateException(IEnumerable<Exception> innerExceptions) :
this(Environment.GetResourceString("AggregateException_ctor_DefaultMessage"), innerExceptions)
{
}
/// <summary>
/// Initializes a new instance of the <see cref="AggregateException"/> class with
/// references to the inner exceptions that are the cause of this exception.
/// </summary>
/// <param name="innerExceptions">The exceptions that are the cause of the current exception.</param>
/// <exception cref="T:System.ArgumentNullException">The <paramref name="innerExceptions"/> argument
/// is null.</exception>
/// <exception cref="T:System.ArgumentException">An element of <paramref name="innerExceptions"/> is
/// null.</exception>
public AggregateException(params Exception[] innerExceptions) :
this(Environment.GetResourceString("AggregateException_ctor_DefaultMessage"), innerExceptions)
{
}
/// <summary>
/// Initializes a new instance of the <see cref="AggregateException"/> class with a specified error
/// message and references to the inner exceptions that are the cause of this exception.
/// </summary>
/// <param name="message">The error message that explains the reason for the exception.</param>
/// <param name="innerExceptions">The exceptions that are the cause of the current exception.</param>
/// <exception cref="T:System.ArgumentNullException">The <paramref name="innerExceptions"/> argument
/// is null.</exception>
/// <exception cref="T:System.ArgumentException">An element of <paramref name="innerExceptions"/> is
/// null.</exception>
public AggregateException(string message, IEnumerable<Exception> innerExceptions)
// If it's already an IList, pass that along (a defensive copy will be made in the delegated ctor). If it's null, just pass along
// null typed correctly. Otherwise, create an IList from the enumerable and pass that along.
: this(message, innerExceptions as IList<Exception> ?? (innerExceptions == null ? (List<Exception>)null : new List<Exception>(innerExceptions)))
{
}
/// <summary>
/// Initializes a new instance of the <see cref="AggregateException"/> class with a specified error
/// message and references to the inner exceptions that are the cause of this exception.
/// </summary>
/// <param name="message">The error message that explains the reason for the exception.</param>
/// <param name="innerExceptions">The exceptions that are the cause of the current exception.</param>
/// <exception cref="T:System.ArgumentNullException">The <paramref name="innerExceptions"/> argument
/// is null.</exception>
/// <exception cref="T:System.ArgumentException">An element of <paramref name="innerExceptions"/> is
/// null.</exception>
public AggregateException(string message, params Exception[] innerExceptions) :
this(message, (IList<Exception>)innerExceptions)
{
}
/// <summary>
/// Allocates a new aggregate exception with the specified message and list of inner exceptions.
/// </summary>
/// <param name="message">The error message that explains the reason for the exception.</param>
/// <param name="innerExceptions">The exceptions that are the cause of the current exception.</param>
/// <exception cref="T:System.ArgumentNullException">The <paramref name="innerExceptions"/> argument
/// is null.</exception>
/// <exception cref="T:System.ArgumentException">An element of <paramref name="innerExceptions"/> is
/// null.</exception>
private AggregateException(string message, IList<Exception> innerExceptions)
: base(message, innerExceptions != null && innerExceptions.Count > 0 ? innerExceptions[0] : null)
{
if (innerExceptions == null)
{
throw new ArgumentNullException("innerExceptions");
}
// Copy exceptions to our internal array and validate them. We must copy them,
// because we're going to put them into a ReadOnlyCollection which simply reuses
// the list passed in to it. We don't want callers subsequently mutating.
Exception[] exceptionsCopy = new Exception[innerExceptions.Count];
for (int i = 0; i < exceptionsCopy.Length; i++)
{
exceptionsCopy[i] = innerExceptions[i];
if (exceptionsCopy[i] == null)
{
throw new ArgumentException(Environment.GetResourceString("AggregateException_ctor_InnerExceptionNull"));
}
}
m_innerExceptions = new ReadOnlyCollection<Exception>(exceptionsCopy);
}
/// <summary>
/// Initializes a new instance of the <see cref="AggregateException"/> class with
/// references to the inner exception dispatch info objects that represent the cause of this exception.
/// </summary>
/// <param name="innerExceptionInfos">
/// Information about the exceptions that are the cause of the current exception.
/// </param>
/// <exception cref="T:System.ArgumentNullException">The <paramref name="innerExceptionInfos"/> argument
/// is null.</exception>
/// <exception cref="T:System.ArgumentException">An element of <paramref name="innerExceptionInfos"/> is
/// null.</exception>
internal AggregateException(IEnumerable<ExceptionDispatchInfo> innerExceptionInfos) :
this(Environment.GetResourceString("AggregateException_ctor_DefaultMessage"), innerExceptionInfos)
{
}
/// <summary>
/// Initializes a new instance of the <see cref="AggregateException"/> class with a specified error
/// message and references to the inner exception dispatch info objects that represent the cause of
/// this exception.
/// </summary>
/// <param name="message">The error message that explains the reason for the exception.</param>
/// <param name="innerExceptionInfos">
/// Information about the exceptions that are the cause of the current exception.
/// </param>
/// <exception cref="T:System.ArgumentNullException">The <paramref name="innerExceptionInfos"/> argument
/// is null.</exception>
/// <exception cref="T:System.ArgumentException">An element of <paramref name="innerExceptionInfos"/> is
/// null.</exception>
internal AggregateException(string message, IEnumerable<ExceptionDispatchInfo> innerExceptionInfos)
// If it's already an IList, pass that along (a defensive copy will be made in the delegated ctor). If it's null, just pass along
// null typed correctly. Otherwise, create an IList from the enumerable and pass that along.
: this(message, innerExceptionInfos as IList<ExceptionDispatchInfo> ??
(innerExceptionInfos == null ?
(List<ExceptionDispatchInfo>)null :
new List<ExceptionDispatchInfo>(innerExceptionInfos)))
{
}
/// <summary>
/// Allocates a new aggregate exception with the specified message and list of inner
/// exception dispatch info objects.
/// </summary>
/// <param name="message">The error message that explains the reason for the exception.</param>
/// <param name="innerExceptionInfos">
/// Information about the exceptions that are the cause of the current exception.
/// </param>
/// <exception cref="T:System.ArgumentNullException">The <paramref name="innerExceptionInfos"/> argument
/// is null.</exception>
/// <exception cref="T:System.ArgumentException">An element of <paramref name="innerExceptionInfos"/> is
/// null.</exception>
private AggregateException(string message, IList<ExceptionDispatchInfo> innerExceptionInfos)
: base(message, innerExceptionInfos != null && innerExceptionInfos.Count > 0 && innerExceptionInfos[0] != null ?
innerExceptionInfos[0].SourceException : null)
{
if (innerExceptionInfos == null)
{
throw new ArgumentNullException("innerExceptionInfos");
}
// Copy exceptions to our internal array and validate them. We must copy them,
// because we're going to put them into a ReadOnlyCollection which simply reuses
// the list passed in to it. We don't want callers subsequently mutating.
Exception[] exceptionsCopy = new Exception[innerExceptionInfos.Count];
for (int i = 0; i < exceptionsCopy.Length; i++)
{
var edi = innerExceptionInfos[i];
if (edi != null) exceptionsCopy[i] = edi.SourceException;
if (exceptionsCopy[i] == null)
{
throw new ArgumentException(Environment.GetResourceString("AggregateException_ctor_InnerExceptionNull"));
}
}
m_innerExceptions = new ReadOnlyCollection<Exception>(exceptionsCopy);
}
/// <summary>
/// Initializes a new instance of the <see cref="AggregateException"/> class with serialized data.
/// </summary>
/// <param name="info">The <see cref="T:System.Runtime.Serialization.SerializationInfo"/> that holds
/// the serialized object data about the exception being thrown.</param>
/// <param name="context">The <see cref="T:System.Runtime.Serialization.StreamingContext"/> that
/// contains contextual information about the source or destination. </param>
/// <exception cref="T:System.ArgumentNullException">The <paramref name="info"/> argument is null.</exception>
/// <exception cref="T:System.Runtime.Serialization.SerializationException">The exception could not be deserialized correctly.</exception>
[SecurityCritical]
protected AggregateException(SerializationInfo info, StreamingContext context) :
base(info, context)
{
if (info == null)
{
throw new ArgumentNullException("info");
}
Exception[] innerExceptions = info.GetValue("InnerExceptions", typeof(Exception[])) as Exception[];
if (innerExceptions == null)
{
throw new SerializationException(Environment.GetResourceString("AggregateException_DeserializationFailure"));
}
m_innerExceptions = new ReadOnlyCollection<Exception>(innerExceptions);
}
/// <summary>
/// Sets the <see cref="T:System.Runtime.Serialization.SerializationInfo"/> with information about
/// the exception.
/// </summary>
/// <param name="info">The <see cref="T:System.Runtime.Serialization.SerializationInfo"/> that holds
/// the serialized object data about the exception being thrown.</param>
/// <param name="context">The <see cref="T:System.Runtime.Serialization.StreamingContext"/> that
/// contains contextual information about the source or destination. </param>
/// <exception cref="T:System.ArgumentNullException">The <paramref name="info"/> argument is null.</exception>
[SecurityCritical]
public override void GetObjectData(SerializationInfo info, StreamingContext context)
{
if (info == null)
{
throw new ArgumentNullException("info");
}
base.GetObjectData(info, context);
Exception[] innerExceptions = new Exception[m_innerExceptions.Count];
m_innerExceptions.CopyTo(innerExceptions, 0);
info.AddValue("InnerExceptions", innerExceptions, typeof(Exception[]));
}
/// <summary>
/// Returns the <see cref="System.AggregateException"/> that is the root cause of this exception.
/// </summary>
public override Exception GetBaseException()
{
// Returns the first inner AggregateException that contains more or less than one inner exception
// Recursively traverse the inner exceptions as long as the inner exception of type AggregateException and has only one inner exception
Exception back = this;
AggregateException backAsAggregate = this;
while (backAsAggregate != null && backAsAggregate.InnerExceptions.Count == 1)
{
back = back.InnerException;
backAsAggregate = back as AggregateException;
}
return back;
}
/// <summary>
/// Gets a read-only collection of the <see cref="T:System.Exception"/> instances that caused the
/// current exception.
/// </summary>
public ReadOnlyCollection<Exception> InnerExceptions
{
get { return m_innerExceptions; }
}
/// <summary>
/// Invokes a handler on each <see cref="T:System.Exception"/> contained by this <see
/// cref="AggregateException"/>.
/// </summary>
/// <param name="predicate">The predicate to execute for each exception. The predicate accepts as an
/// argument the <see cref="T:System.Exception"/> to be processed and returns a Boolean to indicate
/// whether the exception was handled.</param>
/// <remarks>
/// Each invocation of the <paramref name="predicate"/> returns true or false to indicate whether the
/// <see cref="T:System.Exception"/> was handled. After all invocations, if any exceptions went
/// unhandled, all unhandled exceptions will be put into a new <see cref="AggregateException"/>
/// which will be thrown. Otherwise, the <see cref="Handle"/> method simply returns. If any
/// invocations of the <paramref name="predicate"/> throws an exception, it will halt the processing
/// of any more exceptions and immediately propagate the thrown exception as-is.
/// </remarks>
/// <exception cref="AggregateException">An exception contained by this <see
/// cref="AggregateException"/> was not handled.</exception>
/// <exception cref="T:System.ArgumentNullException">The <paramref name="predicate"/> argument is
/// null.</exception>
public void Handle(Func<Exception, bool> predicate)
{
if (predicate == null)
{
throw new ArgumentNullException("predicate");
}
List<Exception> unhandledExceptions = null;
for (int i = 0; i < m_innerExceptions.Count; i++)
{
// If the exception was not handled, lazily allocate a list of unhandled
// exceptions (to be rethrown later) and add it.
if (!predicate(m_innerExceptions[i]))
{
if (unhandledExceptions == null)
{
unhandledExceptions = new List<Exception>();
}
unhandledExceptions.Add(m_innerExceptions[i]);
}
}
// If there are unhandled exceptions remaining, throw them.
if (unhandledExceptions != null)
{
throw new AggregateException(Message, unhandledExceptions);
}
}
/// <summary>
/// Flattens an <see cref="AggregateException"/> instances into a single, new instance.
/// </summary>
/// <returns>A new, flattened <see cref="AggregateException"/>.</returns>
/// <remarks>
/// If any inner exceptions are themselves instances of
/// <see cref="AggregateException"/>, this method will recursively flatten all of them. The
/// inner exceptions returned in the new <see cref="AggregateException"/>
/// will be the union of all of the the inner exceptions from exception tree rooted at the provided
/// <see cref="AggregateException"/> instance.
/// </remarks>
public AggregateException Flatten()
{
// Initialize a collection to contain the flattened exceptions.
List<Exception> flattenedExceptions = new List<Exception>();
// Create a list to remember all aggregates to be flattened, this will be accessed like a FIFO queue
List<AggregateException> exceptionsToFlatten = new List<AggregateException>();
exceptionsToFlatten.Add(this);
int nDequeueIndex = 0;
// Continue removing and recursively flattening exceptions, until there are no more.
while (exceptionsToFlatten.Count > nDequeueIndex)
{
// dequeue one from exceptionsToFlatten
IList<Exception> currentInnerExceptions = exceptionsToFlatten[nDequeueIndex++].InnerExceptions;
for (int i = 0; i < currentInnerExceptions.Count; i++)
{
Exception currentInnerException = currentInnerExceptions[i];
if (currentInnerException == null)
{
continue;
}
AggregateException currentInnerAsAggregate = currentInnerException as AggregateException;
// If this exception is an aggregate, keep it around for later. Otherwise,
// simply add it to the list of flattened exceptions to be returned.
if (currentInnerAsAggregate != null)
{
exceptionsToFlatten.Add(currentInnerAsAggregate);
}
else
{
flattenedExceptions.Add(currentInnerException);
}
}
}
return new AggregateException(Message, flattenedExceptions);
}
/// <summary>
/// Creates and returns a string representation of the current <see cref="AggregateException"/>.
/// </summary>
/// <returns>A string representation of the current exception.</returns>
public override string ToString()
{
string text = base.ToString();
for (int i = 0; i < m_innerExceptions.Count; i++)
{
text = String.Format(
CultureInfo.InvariantCulture,
Environment.GetResourceString("AggregateException_ToString"),
text, Environment.NewLine, i, m_innerExceptions[i].ToString(), "<---", Environment.NewLine);
}
return text;
}
/// <summary>
/// This helper property is used by the DebuggerDisplay.
///
/// Note that we don't want to remove this property and change the debugger display to {InnerExceptions.Count}
/// because DebuggerDisplay should be a single property access or parameterless method call, so that the debugger
/// can use a fast path without using the expression evaluator.
///
/// See http://msdn.microsoft.com/en-us/library/x810d419.aspx
/// </summary>
private int InnerExceptionCount
{
get
{
return InnerExceptions.Count;
}
}
}
}
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