//-------------------------------------------------------------
// GACWrap.cs
//
// This implements managed wrappers to GAC API Interfaces
//-------------------------------------------------------------

using System;
using System.Runtime.InteropServices;
using System.Text;

namespace System.GACManagedAccess
{
  //-------------------------------------------------------------
  // Interfaces defined by fusion
  //-------------------------------------------------------------
  [ComImport, InterfaceType(ComInterfaceType.InterfaceIsIUnknown), Guid("e707dcde-d1cd-11d2-bab9-00c04f8eceae")]
  internal interface IAssemblyCache
  {
    [PreserveSig()]
    int UninstallAssembly(
                        int flags,
                        [MarshalAs(UnmanagedType.LPWStr)]
                            String assemblyName,
                        InstallReference refData,
                        out AssemblyCacheUninstallDisposition disposition);

    [PreserveSig()]
    int QueryAssemblyInfo(
                        int flags,
                        [MarshalAs(UnmanagedType.LPWStr)]
                            String assemblyName,
                        ref AssemblyInfo assemblyInfo);
    [PreserveSig()]
    int Reserved(
                        int flags,
                        IntPtr pvReserved,
                        out Object ppAsmItem,
                        [MarshalAs(UnmanagedType.LPWStr)]
                            String assemblyName);
    [PreserveSig()]
    int Reserved(out Object ppAsmScavenger);

    [PreserveSig()]
    int InstallAssembly(
                        int flags,
                        [MarshalAs(UnmanagedType.LPWStr)]
                            String assemblyFilePath,
                        InstallReference refData);
  }// IAssemblyCache

  [ComImport, InterfaceType(ComInterfaceType.InterfaceIsIUnknown), Guid("CD193BC0-B4BC-11d2-9833-00C04FC31D2E")]
  internal interface IAssemblyName
  {
    [PreserveSig()]
    int SetProperty(
            int PropertyId,
            IntPtr pvProperty,
            int cbProperty);

    [PreserveSig()]
    int GetProperty(
            int PropertyId,
            IntPtr pvProperty,
            ref int pcbProperty);

    [PreserveSig()]
    int Finalize();

    [PreserveSig()]
    int GetDisplayName(
            StringBuilder pDisplayName,
            ref int pccDisplayName,
            int displayFlags);

    [PreserveSig()]
    int Reserved(ref Guid guid,
        Object obj1,
        Object obj2,
        String string1,
        Int64 llFlags,
        IntPtr pvReserved,
        int cbReserved,
        out IntPtr ppv);

    [PreserveSig()]
    int GetName(
            ref int pccBuffer,
            StringBuilder pwzName);

    [PreserveSig()]
    int GetVersion(
            out int versionHi,
            out int versionLow);
    [PreserveSig()]
    int IsEqual(
            IAssemblyName pAsmName,
            int cmpFlags);

    [PreserveSig()]
    int Clone(out IAssemblyName pAsmName);
  }// IAssemblyName

  [ComImport, InterfaceType(ComInterfaceType.InterfaceIsIUnknown), Guid("21b8916c-f28e-11d2-a473-00c04f8ef448")]
  internal interface IAssemblyEnum
  {
    [PreserveSig()]
    int GetNextAssembly(
            IntPtr pvReserved,
            out IAssemblyName ppName,
            int flags);
    [PreserveSig()]
    int Reset();
    [PreserveSig()]
    int Clone(out IAssemblyEnum ppEnum);
  }// IAssemblyEnum

  [ComImport, InterfaceType(ComInterfaceType.InterfaceIsIUnknown), Guid("582dac66-e678-449f-aba6-6faaec8a9394")]
  internal interface IInstallReferenceItem
  {
    // A pointer to a FUSION_INSTALL_REFERENCE structure. 
    // The memory is allocated by the GetReference method and is freed when 
    // IInstallReferenceItem is released. Callers must not hold a reference to this 
    // buffer after the IInstallReferenceItem object is released. 
    // This uses the InstallReferenceOutput object to avoid allocation 
    // issues with the interop layer. 
    // This cannot be marshaled directly - must use IntPtr 
    [PreserveSig()]
    int GetReference(
            out IntPtr pRefData,
            int flags,
            IntPtr pvReserced);
  }// IInstallReferenceItem

  [ComImport, InterfaceType(ComInterfaceType.InterfaceIsIUnknown), Guid("56b1a988-7c0c-4aa2-8639-c3eb5a90226f")]
  internal interface IInstallReferenceEnum
  {
    [PreserveSig()]
    int GetNextInstallReferenceItem(
            out IInstallReferenceItem ppRefItem,
            int flags,
            IntPtr pvReserced);
  }// IInstallReferenceEnum

  public enum AssemblyCommitFlags
  {
    Default = 1,
    Force = 2
  }// enum AssemblyCommitFlags

  public enum AssemblyCacheUninstallDisposition
  {
    Unknown = 0,
    Uninstalled = 1,
    StillInUse = 2,
    AlreadyUninstalled = 3,
    DeletePending = 4,
    HasInstallReference = 5,
    ReferenceNotFound = 6
  }

  [Flags]
  internal enum AssemblyCacheFlags
  {
    GAC = 2,
  }

  internal enum CreateAssemblyNameObjectFlags
  {
    CANOF_DEFAULT = 0,
    CANOF_PARSE_DISPLAY_NAME = 1,
  }

  [Flags]
  internal enum AssemblyNameDisplayFlags
  {
    VERSION = 0x01,
    CULTURE = 0x02,
    PUBLIC_KEY_TOKEN = 0x04,
    PROCESSORARCHITECTURE = 0x20,
    RETARGETABLE = 0x80,
    // This enum will change in the future to include
    // more attributes.
    ALL = VERSION
                                | CULTURE
                                | PUBLIC_KEY_TOKEN
                                | PROCESSORARCHITECTURE
                                | RETARGETABLE
  }

  [StructLayout(LayoutKind.Sequential)]
  public class InstallReference
  {
    public InstallReference(Guid guid, String id, String data)
    {
      cbSize = (int)(2 * IntPtr.Size + 16 + (id.Length + data.Length) * 2);
      flags = 0;
      // quiet compiler warning 
      if (flags == 0) { }
      guidScheme = guid;
      identifier = id;
      description = data;
    }

    public Guid GuidScheme
    {
      get { return guidScheme; }
    }

    public String Identifier
    {
      get { return identifier; }
    }

    public String Description
    {
      get { return description; }
    }

    int cbSize;
    int flags;
    Guid guidScheme;
    [MarshalAs(UnmanagedType.LPWStr)]
    String identifier;
    [MarshalAs(UnmanagedType.LPWStr)]
    String description;
  }

  [StructLayout(LayoutKind.Sequential)]
  internal struct AssemblyInfo
  {
    public int cbAssemblyInfo; // size of this structure for future expansion
    public int assemblyFlags;
    public long assemblySizeInKB;
    [MarshalAs(UnmanagedType.LPWStr)]
    public String currentAssemblyPath;
    public int cchBuf; // size of path buf.
  }

  [ComVisible(false)]
  public class InstallReferenceGuid
  {
    public static bool IsValidGuidScheme(Guid guid)
    {
      return (guid.Equals(UninstallSubkeyGuid) ||
              guid.Equals(FilePathGuid) ||
              guid.Equals(OpaqueGuid) ||
              guid.Equals(Guid.Empty));
    }

    public readonly static Guid UninstallSubkeyGuid = new Guid("8cedc215-ac4b-488b-93c0-a50a49cb2fb8");
    public readonly static Guid FilePathGuid = new Guid("b02f9d65-fb77-4f7a-afa5-b391309f11c9");
    public readonly static Guid OpaqueGuid = new Guid("2ec93463-b0c3-45e1-8364-327e96aea856");
    // these GUID cannot be used for installing into GAC.
    public readonly static Guid MsiGuid = new Guid("25df0fc1-7f97-4070-add7-4b13bbfd7cb8");
    public readonly static Guid OsInstallGuid = new Guid("d16d444c-56d8-11d5-882d-0080c847b195");
  }

  [ComVisible(false)]
  public static class AssemblyCache
  {
    public static void InstallAssembly(String assemblyPath, InstallReference reference, AssemblyCommitFlags flags)
    {
      if (reference != null)
      {
        if (!InstallReferenceGuid.IsValidGuidScheme(reference.GuidScheme))
          throw new ArgumentException("Invalid reference guid.", "guid");
      }

      IAssemblyCache ac = null;

      int hr = 0;

      hr = Utils.CreateAssemblyCache(out ac, 0);
      if (hr >= 0)
      {
        hr = ac.InstallAssembly((int)flags, assemblyPath, reference);
      }

      if (hr < 0)
      {
        Marshal.ThrowExceptionForHR(hr);
      }
    }

    // assemblyName has to be fully specified name. 
    // A.k.a, for v1.0/v1.1 assemblies, it should be "name, Version=xx, Culture=xx, PublicKeyToken=xx".
    // For v2.0 assemblies, it should be "name, Version=xx, Culture=xx, PublicKeyToken=xx, ProcessorArchitecture=xx".
    // If assemblyName is not fully specified, a random matching assembly will be uninstalled. 
    public static void UninstallAssembly(String assemblyName, InstallReference reference, out AssemblyCacheUninstallDisposition disp)
    {
      AssemblyCacheUninstallDisposition dispResult = AssemblyCacheUninstallDisposition.Uninstalled;
      if (reference != null)
      {
        if (!InstallReferenceGuid.IsValidGuidScheme(reference.GuidScheme))
          throw new ArgumentException("Invalid reference guid.", "guid");
      }

      IAssemblyCache ac = null;

      int hr = Utils.CreateAssemblyCache(out ac, 0);
      if (hr >= 0)
      {
        hr = ac.UninstallAssembly(0, assemblyName, reference, out dispResult);
      }

      if (hr < 0)
      {
        Marshal.ThrowExceptionForHR(hr);
      }

      disp = dispResult;
    }

    // See comments in UninstallAssembly
    public static String QueryAssemblyInfo(String assemblyName)
    {
      if (assemblyName == null)
      {
        throw new ArgumentException("Invalid name", "assemblyName");
      }

      AssemblyInfo aInfo = new AssemblyInfo();

      aInfo.cchBuf = 1024;
      // Get a string with the desired length
      aInfo.currentAssemblyPath = new String('\0', aInfo.cchBuf);

      IAssemblyCache ac = null;
      int hr = Utils.CreateAssemblyCache(out ac, 0);
      if (hr >= 0)
      {
        hr = ac.QueryAssemblyInfo(0, assemblyName, ref aInfo);
      }
      if (hr < 0)
      {
        Marshal.ThrowExceptionForHR(hr);
      }

      return aInfo.currentAssemblyPath;
    }
  }

  [ComVisible(false)]
  public class AssemblyCacheEnum
  {
    // null means enumerate all the assemblies
    public AssemblyCacheEnum(String assemblyName)
    {
      IAssemblyName fusionName = null;
      int hr = 0;

      if (assemblyName != null)
      {
        hr = Utils.CreateAssemblyNameObject(
                out fusionName,
                assemblyName,
                CreateAssemblyNameObjectFlags.CANOF_PARSE_DISPLAY_NAME,
                IntPtr.Zero);
      }

      if (hr >= 0)
      {
        hr = Utils.CreateAssemblyEnum(
                out m_AssemblyEnum,
                IntPtr.Zero,
                fusionName,
                AssemblyCacheFlags.GAC,
                IntPtr.Zero);
      }

      if (hr < 0)
      {
        Marshal.ThrowExceptionForHR(hr);
      }
    }

    public String GetNextAssembly()
    {
      int hr = 0;
      IAssemblyName fusionName = null;

      if (done)
      {
        return null;
      }

      // Now get next IAssemblyName from m_AssemblyEnum
      hr = m_AssemblyEnum.GetNextAssembly((IntPtr)0, out fusionName, 0);

      if (hr < 0)
      {
        Marshal.ThrowExceptionForHR(hr);
      }

      if (fusionName != null)
      {
        return GetFullName(fusionName);
      }
      else
      {
        done = true;
        return null;
      }
    }

    private String GetFullName(IAssemblyName fusionAsmName)
    {
      StringBuilder sDisplayName = new StringBuilder(1024);
      int iLen = 1024;

      int hr = fusionAsmName.GetDisplayName(sDisplayName, ref iLen, (int)AssemblyNameDisplayFlags.ALL);
      if (hr < 0)
      {
        Marshal.ThrowExceptionForHR(hr);
      }

      return sDisplayName.ToString();
    }

    private IAssemblyEnum m_AssemblyEnum = null;
    private bool done;
  }// class AssemblyCacheEnum

  public class AssemblyCacheInstallReferenceEnum
  {
    public AssemblyCacheInstallReferenceEnum(String assemblyName)
    {
      IAssemblyName fusionName = null;

      int hr = Utils.CreateAssemblyNameObject(
                  out fusionName,
                  assemblyName,
                  CreateAssemblyNameObjectFlags.CANOF_PARSE_DISPLAY_NAME,
                  IntPtr.Zero);

      if (hr >= 0)
      {
        hr = Utils.CreateInstallReferenceEnum(out refEnum, fusionName, 0, IntPtr.Zero);
      }

      if (hr < 0)
      {
        Marshal.ThrowExceptionForHR(hr);
      }
    }

    public InstallReference GetNextReference()
    {
      IInstallReferenceItem item = null;
      int hr = refEnum.GetNextInstallReferenceItem(out item, 0, IntPtr.Zero);
      if ((uint)hr == 0x80070103)
      {   // ERROR_NO_MORE_ITEMS
        return null;
      }

      if (hr < 0)
      {
        Marshal.ThrowExceptionForHR(hr);
      }

      IntPtr refData;
      InstallReference instRef = new InstallReference(Guid.Empty, String.Empty, String.Empty);

      hr = item.GetReference(out refData, 0, IntPtr.Zero);
      if (hr < 0)
      {
        Marshal.ThrowExceptionForHR(hr);
      }

      Marshal.PtrToStructure(refData, instRef);
      return instRef;
    }

    private IInstallReferenceEnum refEnum;
  }

  internal class Utils
  {
    [DllImport("fusion.dll")]
    internal static extern int CreateAssemblyEnum(
            out IAssemblyEnum ppEnum,
            IntPtr pUnkReserved,
            IAssemblyName pName,
            AssemblyCacheFlags flags,
            IntPtr pvReserved);

    [DllImport("fusion.dll")]
    internal static extern int CreateAssemblyNameObject(
            out IAssemblyName ppAssemblyNameObj,
            [MarshalAs(UnmanagedType.LPWStr)]
                String szAssemblyName,
            CreateAssemblyNameObjectFlags flags,
            IntPtr pvReserved);

    [DllImport("fusion.dll")]
    internal static extern int CreateAssemblyCache(
            out IAssemblyCache ppAsmCache,
            int reserved);

    [DllImport("fusion.dll")]
    internal static extern int CreateInstallReferenceEnum(
            out IInstallReferenceEnum ppRefEnum,
            IAssemblyName pName,
            int dwFlags,
            IntPtr pvReserved);
  }
}