MetaDataInfo.cs source code in C# .NET

                        Code:
                         / 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / fx / src / Wmi / managed / System / Management / Instrumentation / MetaDataInfo.cs / 1305376 / MetaDataInfo.cs
                        
                        
                            //------------------------------------------------------------------------------
// 
//    Copyright (c) Microsoft Corporation. All Rights Reserved.
//    Information Contained Herein is Proprietary and Confidential. 
// 
//----------------------------------------------------------------------------- 
 
namespace System.Management.Instrumentation
{ 
    using System;
    using System.Reflection;
    using System.Runtime.InteropServices;
    using System.Runtime.CompilerServices; 
    using System.Text;
    using System.Runtime.Versioning; 
 
    /// 
    /// CoClass for getting an IMetaDataDispenser 
    /// 
    [ComImport]
    [Guid("E5CB7A31-7512-11d2-89CE-0080C792E5D8")]
    [TypeLibType(TypeLibTypeFlags.FCanCreate) /*0x0002*/] 
    [ClassInterface(ClassInterfaceType.None  /*(short)0x0000*/)]
    class CorMetaDataDispenser 
    { 
    }
 
    /// 
    /// This version of the IMetaDataDispenser interface defines
    /// the interfaces so that the last parameter from cor.h
    /// is the return value of the methods.  The 'raw' way to 
    /// implement these methods is as follows:
    ///    void OpenScope( 
    ///        [In][MarshalAs(UnmanagedType.LPWStr)]  string   szScope, 
    ///        [In] UInt32 dwOpenFlags,
    ///        [In] ref Guid riid, 
    ///        [Out] out IntPtr ppIUnk);
    /// The way to call this other version is as follows
    ///    IntPtr unk;
    ///    dispenser.OpenScope(assemblyName, 0, ref guidIMetaDataImport, out unk); 
    ///    importInterface = (IMetaDataImport)Marshal.GetObjectForIUnknown(unk);
    ///    Marshal.Release(unk); 
    ///  
    [ComImport]
    [Guid("809c652e-7396-11d2-9771-00a0c9b4d50c")] 
    [InterfaceType(ComInterfaceType.InterfaceIsIUnknown /*0x0001*/)]
    [TypeLibType(TypeLibTypeFlags.FRestricted /*0x0200*/)]
    interface IMetaDataDispenser
    { 
        [return:MarshalAs(UnmanagedType.Interface)]
        object DefineScope( 
            [In] ref Guid rclsid, 
            [In] UInt32  dwCreateFlags,
            [In] ref Guid riid); 

        [return:MarshalAs(UnmanagedType.Interface)]
        object OpenScope(
            [In][MarshalAs(UnmanagedType.LPWStr)]  string   szScope, 
            [In] UInt32 dwOpenFlags,
            [In] ref Guid riid); 
 
        [return:MarshalAs(UnmanagedType.Interface)]
        object OpenScopeOnMemory( 
            [In] IntPtr pData,
            [In] UInt32 cbData,
            [In] UInt32 dwOpenFlags,
            [In] ref Guid riid); 
    }
 
 
    /// 
    /// This class is an INCOMPLETE IMPLEMENTATION OF IMetaDataImport.  For the purposes of 
    /// System.Management.dll, we only needed to call one method, GetScopeProps
    /// 
    [ComImport]
    [Guid("7DAC8207-D3AE-4c75-9B67-92801A497D44")] 
    [InterfaceType(ComInterfaceType.InterfaceIsIUnknown /*0x0001*/)]
    [TypeLibType(TypeLibTypeFlags.FRestricted /*0x0200*/)] 
    interface IMetaDataImportInternalOnly 
    {
        void f1(); 
        void f2();
        void f3();
        void f4();
        void f5(); 
        void f6();
        void f7(); 
        void GetScopeProps( 
            [Out][MarshalAs(UnmanagedType.LPWStr)] StringBuilder szName,
            [In] UInt32 cchName, 
            [Out] out UInt32 pchName,
            [Out] out Guid pmvid);
    }
 

    ///  
    /// This class wraps the functionality of IMetaDataImport.  It abstracts the 
    /// details of working directly with the interface.
    ///  
    class MetaDataInfo : IDisposable
    {
        [ResourceExposure(ResourceScope.None),ResourceConsumption(ResourceScope.Machine,ResourceScope.Machine)]
        public MetaDataInfo(Assembly assembly) : this(assembly.Location) {} 

        public MetaDataInfo(string assemblyName) 
        { 
            // Get guid for IMetaDataImport
            Guid guidIMetaDataImport = new Guid(((GuidAttribute)Attribute.GetCustomAttribute(typeof(IMetaDataImportInternalOnly), typeof(GuidAttribute), false)).Value); 

            // Get an IMetaDataImport for the assembly from a dispenser
            IMetaDataDispenser dispenser = (IMetaDataDispenser)new CorMetaDataDispenser();
            importInterface = (IMetaDataImportInternalOnly)dispenser.OpenScope(assemblyName, 0, ref guidIMetaDataImport); 
            Marshal.ReleaseComObject(dispenser);
        } 
 
        IMetaDataImportInternalOnly importInterface;
 
        // These two fields are initialized the first time either is requested
        // They are both retrieved through IMetaDataImport GetScopeProps
        string name = null;
        Guid mvid; 

        void InitNameAndMvid() 
        { 
            // If we have never retrieved the name and MVID, get them now
            if(null==name) 
            {
                UInt32 cchName;
                StringBuilder sb = new StringBuilder();
                sb.Capacity = 0; 
                importInterface.GetScopeProps(sb, (UInt32)sb.Capacity, out cchName, out mvid);
                sb.Capacity = (int)cchName; 
                importInterface.GetScopeProps(sb, (UInt32)sb.Capacity, out cchName, out mvid); 
                name = sb.ToString();
            } 
        }

        public string Name
        { 
            get
            { 
                InitNameAndMvid(); 
                return name;
            } 
        }

        public Guid Mvid
        { 
            get
            { 
                InitNameAndMvid(); 
                return mvid;
            } 
        }

        public void Dispose()
        { 
            // We implement IDisposable on this class because the IMetaDataImport
            // can be an expensive object to keep in memory. 
            if(importInterface == null) 
                Marshal.ReleaseComObject(importInterface);
            importInterface = null; 
            GC.SuppressFinalize(this);
        }

        ~MetaDataInfo() 
        {
            Dispose(); 
        } 

        public static Guid GetMvid(Assembly assembly) 
        {
            using(MetaDataInfo info = new MetaDataInfo(assembly))
            {
                return info.Mvid; 
            }
        } 
    } 
}
 

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
// Copyright (c) Microsoft Corporation. All rights reserved.
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MetaDataInfo.cs source code in C# .NET

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