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//------------------------------------------------------------------------------
//
// Copyright (c) Microsoft Corporation, 2005
//
// File: PreloadedPackages.cs
//
// Description: Collection of preloaded packages to be used with
// PackWebRequest.
//
//------------------------------------------------------------------------------
using System;
using System.Security;
using System.Security.Permissions;
using System.Collections;
using System.Collections.Specialized;
using System.Diagnostics;
using System.Globalization;
using System.IO;
using System.IO.Packaging;
using MS.Internal;
using MS.Internal.PresentationCore; // for ExceptionStringTable
namespace MS.Internal.IO.Packaging
{
/// <summary>
/// PreloadedPackages
/// </summary>
/// <remarks>Note: we purposely didn't make this class a dictionary since it is an internal
/// class and we won't be using even half of the dictionary functionalities.
/// If this class becomes a public class which is strongly discouraged, this class
/// needs to implement IDictionary.</remarks>
// <SecurityNote>
// Critical: This class serves as a depository of all well-known pre-populated
// packages. This class is marked as SecurityCritical to ensure that
// 1. only trusted code can add/get/remove trusted packages into the depository
// 2. a whole package will never be given out to the platform client
// Note: it is OK to give out a part stream from a package instance but
// the package related objects such as Package, PackagePart,
// PackageRelationship should NEVER be given out to a client.
// List of the trusted packages allowed:
// 1. ResourceContainer
// 2. SiteOfOriginContainer
// 3. ZipPackage that is only instantiated by XPS Viewer
// </SecurityNote>
[SecurityCritical(SecurityCriticalScope.Everything)]
[FriendAccessAllowed]
internal static class PreloadedPackages
{
//------------------------------------------------------
//
// Static Constructors
//
//------------------------------------------------------
static PreloadedPackages()
{
_globalLock = new Object();
}
//------------------------------------------------------
//
// Internal Methods
//
//------------------------------------------------------
#region Internal Methods
/// <summary>
/// GetPackage given a uri
/// </summary>
/// <param name="uri">uri to match on</param>
/// <returns>object if found - else null</returns>
/// <exception cref="ArgumentException">uri must be absolute</exception>
internal static Package GetPackage(Uri uri)
{
bool ignored;
return GetPackage(uri, out ignored);
}
/// <summary>
/// GetPackage given a uri
/// </summary>
/// <param name="uri">uri to match on</param>
/// <param name="threadSafe">true if the returned package is threadsafe - undefined if null is returned</param>
/// <returns>object if found - else null</returns>
/// <exception cref="ArgumentException">uri must be absolute</exception>
internal static Package GetPackage(Uri uri, out bool threadSafe)
{
ValidateUriKey(uri);
lock (_globalLock)
{
Package package = null;
threadSafe = false;
if (_packagePairs != null)
{
PackageThreadSafePair packagePair = _packagePairs[uri] as PackageThreadSafePair;
if (packagePair != null)
{
package = packagePair.Package;
threadSafe = packagePair.ThreadSafe;
}
}
return package;
}
}
/// <summary>
/// AddPackage - default to non-thread-safe
/// </summary>
/// <param name="uri">uri to use for matching</param>
/// <param name="package">package object to serve content from</param>
/// <remarks>Adds a uri, content pair to the cache. If the uri is already
/// in the cache, this removes the old content and replaces it.
/// The object will not be subject to automatic removal from the cache</remarks>
internal static void AddPackage(Uri uri, Package package)
{
AddPackage(uri, package, false);
}
/// <summary>
/// AddPackage
/// </summary>
/// <param name="uri">uri to use for matching</param>
/// <param name="package">package object to serve content from</param>
/// <param name="threadSafe">is package thread-safe?</param>
/// <remarks>Adds a uri, content pair to the cache. If the uri is already
/// in the cache, this removes the old content and replaces it.
/// The object will not be subject to automatic removal from the cache</remarks>
internal static void AddPackage(Uri uri, Package package, bool threadSafe)
{
ValidateUriKey(uri);
lock (_globalLock)
{
if (_packagePairs == null)
{
_packagePairs = new HybridDictionary(3);
}
_packagePairs.Add(uri, new PackageThreadSafePair(package, threadSafe));
}
}
/// <summary>
/// RemovePackage
/// </summary>
/// <param name="uri">uri of the package that needs to be removed </param>
/// <remarks>Removes the package corresponding to the uri from the cache. If a matching uri isn't found
/// the status of the cache doesn't change and no exception is throwen
/// </remarks>
internal static void RemovePackage(Uri uri)
{
ValidateUriKey(uri);
lock (_globalLock)
{
if (_packagePairs != null)
{
_packagePairs.Remove(uri);
}
}
}
// Null the instance. Similar to Dispose, but not quite.
internal static void Clear()
{
lock (_globalLock)
{
_packagePairs = null;
}
}
private static void ValidateUriKey(Uri uri)
{
if (uri == null)
{
throw new ArgumentNullException("uri");
}
if (!uri.IsAbsoluteUri)
{
throw new ArgumentException(SR.Get(SRID.UriMustBeAbsolute), "uri");
}
}
#endregion Internal Methods
/// <summary>
/// Package-bool pair where the bool represents the thread-safety status of the package
/// </summary>
private class PackageThreadSafePair
{
//------------------------------------------------------
//
// Internal Constructors
//
//------------------------------------------------------
internal PackageThreadSafePair(Package package, bool threadSafe)
{
Invariant.Assert(package != null);
_package = package;
_threadSafe = threadSafe;
}
//------------------------------------------------------
//
// Internal Properties
//
//------------------------------------------------------
/// <summary>
/// Package
/// </summary>
internal Package Package
{
get
{
return _package;
}
}
/// <summary>
/// True if package is thread-safe
/// </summary>
internal bool ThreadSafe
{
get
{
return _threadSafe;
}
}
//------------------------------------------------------
//
// Private Fields
//
//------------------------------------------------------
private readonly Package _package;
private readonly bool _threadSafe;
}
//------------------------------------------------------
//
// Private Fields
//
//------------------------------------------------------
#region Private Fields
// We are expect to have no more than 10 preloaded packages
// per AppDomain for our scenarios
// ListDictionary is the best fit for this scenarios; otherwise we should be using
// Hashtable. HybridDictionary already has functionality of switching between
// ListDictionary and Hashtable depending on the size of the collection
static private HybridDictionary _packagePairs;
static private Object _globalLock;
#endregion Private Fields
}
}
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