ResourcePart.cs source code in C# .NET

Source code for the .NET framework in C#

                        
Code:

                         / DotNET / DotNET / 8.0 / untmp / WIN_WINDOWS / lh_tools_devdiv_wpf / Windows / wcp / Framework / MS / Internal / AppModel / ResourcePart.cs / 1 / ResourcePart.cs
                        

                        
                            //------------------------------------------------------------------------------ 
//
// 
//    Copyright (C) Microsoft Corporation.  All rights reserved.
//  
//
// Description: 
// ResourcePart is an implementation of the abstract PackagePart class. It contains an override for GetStreamCore. 
//
// History: 
//  10/04/2004: [....]: Initial creation.
//
//-----------------------------------------------------------------------------
 
using System;
using System.IO.Packaging; 
using System.Windows; 
using System.Windows.Resources;
using System.IO; 
using System.Resources;
using System.Globalization;
using System.Security;
 
using MS.Internal.Resources;
using MS.Internal; 
 
//In order to avoid generating warnings about unknown message numbers and
//unknown pragmas when compiling your C# source code with the actual C# compiler, 
//you need to disable warnings 1634 and 1691. (Presharp Documentation)
#pragma warning disable 1634, 1691

 
namespace MS.Internal.AppModel
{ 
 
    /// 
    /// ResourcePart is an implementation of the abstract PackagePart class. It contains an override for GetStreamCore. 
    /// 
    internal class ResourcePart : System.IO.Packaging.PackagePart
    {
        //----------------------------------------------------- 
        //
        //  Public Constructors 
        // 
        //-----------------------------------------------------
 
        #region Public Constructors

        /// 
        ///     Critical - because _rmWrapper, which is being set, is marked SecurityCriticalDataForSet. 
        /// 
        [SecurityCritical] 
        public ResourcePart(Package container, Uri uri, string name, ResourceManagerWrapper rmWrapper) : 
            base(container, uri)
        { 
            _rmWrapper.Value = rmWrapper;
            _name = name;
        }
 
        #endregion
 
        //------------------------------------------------------ 
        //
        //  Protected Methods 
        //
        //-----------------------------------------------------

        #region Protected Methods 

        ///  
        ///     Critical - because creating a BamlStream is critical as it stores the assembly 
        ///                passed in to it the _assembly field, and this field is used by the
        ///                BamlRecordReader to allow legitimate internal types in Partial Trust. 
        ///     Safe - because the _rmWrapper from which the assembly is obtained is SecurityCriticalDataForSet,
        ///            and setting that when a ResourcePart is constructed is treated as safe by
        ///            ResourceContainer.GetPartCore(). The _rmWrapper is trated as safe as it guarantees
        ///            that any stream created by it is always from the assembly that it also holds on to. 
        ///            So to the BamlRecordReader, this Assembly that it uses is always guaranteed to be
        ///            the one from which the baml stream that it reads, was created from. 
        ///  
        [SecurityCritical, SecurityTreatAsSafe]
        protected override Stream GetStreamCore(FileMode mode, FileAccess access) 
        {
            Stream stream = null;

            stream = EnsureResourceLocationSet(); 
            // in order to find the resource we might have to open a stream.
            // rather than waste the stream it is returned here and we can use it. 
            if (stream == null) 
            {
                // Start looking for resources using the current ui culture. 
                // The resource manager will fall back to invariant culture automatically.
                stream = _rmWrapper.Value.GetStream(_name);

                if (stream == null) 
                {
                    throw new IOException(SR.Get(SRID.UnableToLocateResource, _name)); 
                } 
            }
 
            //
            // If this is a Baml stream, it will return BamlStream object, which contains
            // both raw stream and the host assembly.
            // 
            ContentType  curContent = new ContentType(ContentType);
 
            if (MimeTypeMapper.BamlMime.AreTypeAndSubTypeEqual(curContent)) 
            {
                BamlStream bamlStream = new BamlStream(stream, _rmWrapper.Value.Assembly); 

                stream = bamlStream;
            }
 
            return stream;
        } 
 
        protected override string GetContentTypeCore()
        { 
            EnsureResourceLocationSet();

            return MS.Internal.MimeTypeMapper.GetMimeTypeFromUri(new Uri(_name,UriKind.RelativeOrAbsolute)).ToString();
        } 

        #endregion 
 
        //------------------------------------------------------
        // 
        //  Private Methods
        //
        //------------------------------------------------------
 
        #region Private Methods
 
        private Stream EnsureResourceLocationSet() 
        {
            Stream stream = null; 

            lock (_globalLock)
            {
                // only need to do this once 
                if (_ensureResourceIsCalled)
                { 
                    return null; 
                }
                _ensureResourceIsCalled = true; 

                try
                {
                    // We do not allow the use of .baml in any Avalon public APIs. This is the code pass needed to go through for loading baml file. 
                    // Throw here we will catch all those cases.
                    if (String.Compare(Path.GetExtension(_name), ResourceContainer.BamlExt, StringComparison.OrdinalIgnoreCase) == 0) 
                    { 
                        throw new IOException(SR.Get(SRID.UnableToLocateResource, _name));
                    } 

                    if (String.Compare(Path.GetExtension(_name), ResourceContainer.XamlExt, StringComparison.OrdinalIgnoreCase) == 0)
                    {
                        // try baml extension first since it's our most common senario. 
                        string newName = Path.ChangeExtension(_name, ResourceContainer.BamlExt);
 
                        // Get resource from resource manager wrapper. 
                        stream = _rmWrapper.Value.GetStream(newName);
                        if (stream != null) 
                        {
                            // Remember that we have .baml for next time GetStreamCore is called.
                            _name = newName;
                            return stream; 
                        }
                    } 
                } 
#pragma warning disable 6502 // PRESharp - Catch statements should not have empty bodies
                catch (System.Resources.MissingManifestResourceException) 
                {
                    // When the main assembly doesn't contain any resource (all the resources must come from satellite assembly)
                    // then above GetStream( ) just throws exception. We should catch this exception here and let the code continue
                    // to try with the original file name. 

                    // If the main assembly does contain resource, but the resource with above _name does't exist, the above GetStream( ) 
                    // just returns null without exception. 
                }
#pragma warning restore 6502 

            }

            // Do not attempt to load the original file name here.  If the .baml does not exist or if this resource not 
            // .xaml or .baml then we will follow the normal code path to attempt to load the stream using the original name.
 
            return null; 
        }
 
        #endregion

        //-----------------------------------------------------
        // 
        //  Private Fields
        // 
        //------------------------------------------------------ 

        #region Private Members 

        private SecurityCriticalDataForSet _rmWrapper;
        private bool _ensureResourceIsCalled = false;
        private string _name; 
        private Object _globalLock = new Object();
 
        #endregion Private Members 
    }
} 


// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
// Copyright (c) Microsoft Corporation. All rights reserved.

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