// Copyright © Microsoft Corporation.
// This source file is subject to the Microsoft Permissive License.
// See http://www.microsoft.com/resources/sharedsource/licensingbasics/sharedsourcelicenses.mspx.
// All other rights reserved.

#if !ROTOR
using System;
using System.Collections;
using System.Diagnostics;
using System.IO;
using System.Runtime.InteropServices;
using System.Text;

#if CCINamespace
namespace Microsoft.Cci{
#else
namespace System.Compiler
{
#endif
#if !FxCop
    public
#endif
 class GlobalAssemblyCache
    {
        private GlobalAssemblyCache() { }
        private static readonly object Lock = new object();
        private static bool FusionLoaded;

        /// <param name="codeBaseUri">Uri pointing to the assembly</param>
        public static bool Contains(Uri codeBaseUri)
        {
            if (codeBaseUri == null) { Debug.Fail("codeBaseUri == null"); return false; }
            lock (GlobalAssemblyCache.Lock)
            {
                if (!GlobalAssemblyCache.FusionLoaded)
                {
                    GlobalAssemblyCache.FusionLoaded = true;
                    System.Reflection.Assembly systemAssembly = typeof(object).Assembly;
                    //^ assume systemAssembly != null && systemAssembly.Location != null;
                    string dir = Path.GetDirectoryName(systemAssembly.Location);
                    //^ assume dir != null;
                    GlobalAssemblyCache.LoadLibrary(Path.Combine(dir, "fusion.dll"));
                }
                IAssemblyEnum assemblyEnum;
                int rc = GlobalAssemblyCache.CreateAssemblyEnum(out assemblyEnum, null, null, ASM_CACHE.GAC, 0);
                if (rc < 0 || assemblyEnum == null) return false;
                IApplicationContext applicationContext;
                IAssemblyName currentName;
                while (assemblyEnum.GetNextAssembly(out applicationContext, out currentName, 0) == 0)
                {
                    //^ assume currentName != null;
                    AssemblyName assemblyName = new AssemblyName(currentName);
                    string scheme = codeBaseUri.Scheme;
                    if (scheme != null && assemblyName.CodeBase.StartsWith(scheme))
                    {
                        try
                        {
                            Uri foundUri = new Uri(assemblyName.CodeBase);
                            if (codeBaseUri.Equals(foundUri)) return true;
#if !FxCop
                        }
                        catch (Exception)
                        {
#else
            }finally{
#endif
                        }
                    }
                }
                return false;
            }
        }
        /// <summary>
        /// Returns the original location of the corresponding assembly if available, otherwise returns the location of the shadow copy.
        /// If the corresponding assembly is not in the GAC, null is returned.
        /// </summary>
        public static string GetLocation(AssemblyReference assemblyReference)
        {
            if (assemblyReference == null) { Debug.Fail("assemblyReference == null"); return null; }
            lock (GlobalAssemblyCache.Lock)
            {
                if (!GlobalAssemblyCache.FusionLoaded)
                {
                    GlobalAssemblyCache.FusionLoaded = true;
                    System.Reflection.Assembly systemAssembly = typeof(object).Assembly;
                    //^ assume systemAssembly != null && systemAssembly.Location != null;
                    string dir = Path.GetDirectoryName(systemAssembly.Location);
                    //^ assume dir != null;
                    GlobalAssemblyCache.LoadLibrary(Path.Combine(dir, "fusion.dll"));
                }
                IAssemblyEnum assemblyEnum;
                CreateAssemblyEnum(out assemblyEnum, null, null, ASM_CACHE.GAC, 0);
                if (assemblyEnum == null) return null;
                IApplicationContext applicationContext;
                IAssemblyName currentName;
                while (assemblyEnum.GetNextAssembly(out applicationContext, out currentName, 0) == 0)
                {
                    //^ assume currentName != null;
                    AssemblyName aName = new AssemblyName(currentName);
                    if (assemblyReference.Matches(aName.Name, aName.Version, aName.Culture, aName.PublicKeyToken))
                    {
                        string codeBase = aName.CodeBase;
                        if (codeBase != null && codeBase.StartsWith("file:///"))
                            return codeBase.Substring(8);
                        return aName.GetLocation();
                    }
                }
                return null;
            }
        }

        [DllImport("kernel32.dll", CharSet = CharSet.Ansi)]
        private static extern IntPtr LoadLibrary(string lpFileName);
        [DllImport("fusion.dll", CharSet = CharSet.Auto)]
        private static extern int CreateAssemblyEnum(out IAssemblyEnum ppEnum, IApplicationContext pAppCtx, IAssemblyName pName, uint dwFlags, int pvReserved);
        private class ASM_CACHE
        {
            private ASM_CACHE() { }
            public const uint ZAP = 1;
            public const uint GAC = 2;
            public const uint DOWNLOAD = 4;
        }
    }
    internal class AssemblyName
    {
        IAssemblyName/*!*/ assemblyName;

        internal AssemblyName(IAssemblyName/*!*/ assemblyName)
        {
            this.assemblyName = assemblyName;
            //^ base();
        }

        internal string/*!*/ Name
        {
            //set {this.WriteString(ASM_NAME.NAME, value);}
            get { return this.ReadString(ASM_NAME.NAME); }
        }
        internal Version Version
        {
            //set{
            //  if (value == null) throw new ArgumentNullException();
            //  this.WriteUInt16(ASM_NAME.MAJOR_VERSION, (ushort)value.Major);
            //  this.WriteUInt16(ASM_NAME.MINOR_VERSION, (ushort)value.Minor);
            //  this.WriteUInt16(ASM_NAME.BUILD_NUMBER, (ushort)value.Build);
            //  this.WriteUInt16(ASM_NAME.REVISION_NUMBER, (ushort)value.Revision);
            //}
            get
            {
                int major = this.ReadUInt16(ASM_NAME.MAJOR_VERSION);
                int minor = this.ReadUInt16(ASM_NAME.MINOR_VERSION);
                int build = this.ReadUInt16(ASM_NAME.BUILD_NUMBER);
                int revision = this.ReadUInt16(ASM_NAME.REVISION_NUMBER);
                return new Version(major, minor, build, revision);
            }
        }
        internal string/*!*/ Culture
        {
            //set {this.WriteString(ASM_NAME.CULTURE, value);}
            get { return this.ReadString(ASM_NAME.CULTURE); }
        }
        internal byte[]/*!*/ PublicKeyToken
        {
            //set {this.WriteBytes(ASM_NAME.PUBLIC_KEY_TOKEN, value); }
            get { return this.ReadBytes(ASM_NAME.PUBLIC_KEY_TOKEN); }
        }
        internal string StrongName
        {
            get
            {
                uint size = 0;
                this.assemblyName.GetDisplayName(null, ref size, (uint)AssemblyNameDisplayFlags.ALL);
                if (size == 0) return "";
                StringBuilder strongName = new StringBuilder((int)size);
                this.assemblyName.GetDisplayName(strongName, ref size, (uint)AssemblyNameDisplayFlags.ALL);
                return strongName.ToString();
            }
        }
        internal string/*!*/ CodeBase
        {
            //set {this.WriteString(ASM_NAME.CODEBASE_URL, value);}
            get { return this.ReadString(ASM_NAME.CODEBASE_URL); }
        }
        public override string ToString()
        {
            return this.StrongName;
        }
        internal string GetLocation()
        {
            IAssemblyCache assemblyCache;
            CreateAssemblyCache(out assemblyCache, 0);
            if (assemblyCache == null) return null;
            ASSEMBLY_INFO assemblyInfo = new ASSEMBLY_INFO();
            assemblyInfo.cbAssemblyInfo = (uint)Marshal.SizeOf(typeof(ASSEMBLY_INFO));
            assemblyCache.QueryAssemblyInfo(ASSEMBLYINFO_FLAG.VALIDATE | ASSEMBLYINFO_FLAG.GETSIZE, this.StrongName, ref assemblyInfo);
            if (assemblyInfo.cbAssemblyInfo == 0) return null;
            assemblyInfo.pszCurrentAssemblyPathBuf = new string(new char[assemblyInfo.cchBuf]);
            assemblyCache.QueryAssemblyInfo(ASSEMBLYINFO_FLAG.VALIDATE | ASSEMBLYINFO_FLAG.GETSIZE, this.StrongName, ref assemblyInfo);
            String value = assemblyInfo.pszCurrentAssemblyPathBuf;
            return value;
        }
        private string/*!*/ ReadString(uint assemblyNameProperty)
        {
            uint size = 0;
            this.assemblyName.GetProperty(assemblyNameProperty, IntPtr.Zero, ref size);
            if (size == 0 || size > Int16.MaxValue) return String.Empty;
            IntPtr ptr = Marshal.AllocHGlobal((int)size);
            this.assemblyName.GetProperty(assemblyNameProperty, ptr, ref size);
            String str = Marshal.PtrToStringUni(ptr);
            //^ assume str != null;
            Marshal.FreeHGlobal(ptr);
            return str;
        }
        private ushort ReadUInt16(uint assemblyNameProperty)
        {
            uint size = 0;
            this.assemblyName.GetProperty(assemblyNameProperty, IntPtr.Zero, ref size);
            IntPtr ptr = Marshal.AllocHGlobal((int)size);
            this.assemblyName.GetProperty(assemblyNameProperty, ptr, ref size);
            ushort value = (ushort)Marshal.ReadInt16(ptr);
            Marshal.FreeHGlobal(ptr);
            return value;
        }
        private byte[]/*!*/ ReadBytes(uint assemblyNameProperty)
        {
            uint size = 0;
            this.assemblyName.GetProperty(assemblyNameProperty, IntPtr.Zero, ref size);
            IntPtr ptr = Marshal.AllocHGlobal((int)size);
            this.assemblyName.GetProperty(assemblyNameProperty, ptr, ref size);
            byte[] value = new byte[(int)size];
            Marshal.Copy(ptr, value, 0, (int)size);
            Marshal.FreeHGlobal(ptr);
            return value;
        }

        [DllImport("fusion.dll", CharSet = CharSet.Auto)]
        private static extern int CreateAssemblyCache(out IAssemblyCache ppAsmCache, uint dwReserved);
        private class CREATE_ASM_NAME_OBJ_FLAGS
        {
            private CREATE_ASM_NAME_OBJ_FLAGS() { }
            public const uint CANOF_PARSE_DISPLAY_NAME = 0x1;
            public const uint CANOF_SET_DEFAULT_VALUES = 0x2;
        }
        private class ASM_NAME
        {
            private ASM_NAME() { }
            public const uint PUBLIC_KEY = 0;
            public const uint PUBLIC_KEY_TOKEN = 1;
            public const uint HASH_VALUE = 2;
            public const uint NAME = 3;
            public const uint MAJOR_VERSION = 4;
            public const uint MINOR_VERSION = 5;
            public const uint BUILD_NUMBER = 6;
            public const uint REVISION_NUMBER = 7;
            public const uint CULTURE = 8;
            public const uint PROCESSOR_ID_ARRAY = 9;
            public const uint OSINFO_ARRAY = 10;
            public const uint HASH_ALGID = 11;
            public const uint ALIAS = 12;
            public const uint CODEBASE_URL = 13;
            public const uint CODEBASE_LASTMOD = 14;
            public const uint NULL_PUBLIC_KEY = 15;
            public const uint NULL_PUBLIC_KEY_TOKEN = 16;
            public const uint CUSTOM = 17;
            public const uint NULL_CUSTOM = 18;
            public const uint MVID = 19;
            public const uint _32_BIT_ONLY = 20;
        }
        [Flags]
        internal enum AssemblyNameDisplayFlags
        {
            VERSION = 0x01,
            CULTURE = 0x02,
            PUBLIC_KEY_TOKEN = 0x04,
            PROCESSORARCHITECTURE = 0x20,
            RETARGETABLE = 0x80,
            ALL = VERSION | CULTURE | PUBLIC_KEY_TOKEN | PROCESSORARCHITECTURE | RETARGETABLE
        }
        private class ASSEMBLYINFO_FLAG
        {
            private ASSEMBLYINFO_FLAG() { }
            public const uint VALIDATE = 1;
            public const uint GETSIZE = 2;
        }
        [StructLayout(LayoutKind.Sequential)]
        private struct ASSEMBLY_INFO
        {
            public uint cbAssemblyInfo;
            public uint dwAssemblyFlags;
            public ulong uliAssemblySizeInKB;
            [MarshalAs(UnmanagedType.LPWStr)]
            public string pszCurrentAssemblyPathBuf;
            public uint cchBuf;
        }
        [ComImport(), Guid("E707DCDE-D1CD-11D2-BAB9-00C04F8ECEAE"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
        private interface IAssemblyCache
        {
            [PreserveSig()]
            int UninstallAssembly(uint dwFlags, [MarshalAs(UnmanagedType.LPWStr)] string pszAssemblyName, IntPtr pvReserved, int pulDisposition);
            [PreserveSig()]
            int QueryAssemblyInfo(uint dwFlags, [MarshalAs(UnmanagedType.LPWStr)] string pszAssemblyName, ref ASSEMBLY_INFO pAsmInfo);
            [PreserveSig()]
            int CreateAssemblyCacheItem(uint dwFlags, IntPtr pvReserved, out object ppAsmItem, [MarshalAs(UnmanagedType.LPWStr)] string pszAssemblyName);
            [PreserveSig()]
            int CreateAssemblyScavenger(out object ppAsmScavenger);
            [PreserveSig()]
            int InstallAssembly(uint dwFlags, [MarshalAs(UnmanagedType.LPWStr)] string pszManifestFilePath, IntPtr pvReserved);
        }
    }
    [ComImport(), Guid("CD193BC0-B4BC-11D2-9833-00C04FC31D2E"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
    interface IAssemblyName
    {
        [PreserveSig()]
        int SetProperty(uint PropertyId, IntPtr pvProperty, uint cbProperty);
        [PreserveSig()]
        int GetProperty(uint PropertyId, IntPtr pvProperty, ref uint pcbProperty);
        [PreserveSig()]
        int Finalize();
        [PreserveSig()]
        int GetDisplayName(StringBuilder szDisplayName, ref uint pccDisplayName, uint dwDisplayFlags);
        [PreserveSig()]
        int BindToObject(object refIID, object pAsmBindSink, IApplicationContext pApplicationContext, [MarshalAs(UnmanagedType.LPWStr)] string szCodeBase, long llFlags, int pvReserved, uint cbReserved, out int ppv);
        [PreserveSig()]
        int GetName(out uint lpcwBuffer, out int pwzName);
        [PreserveSig()]
        int GetVersion(out uint pdwVersionHi, out uint pdwVersionLow);
        [PreserveSig()]
        int IsEqual(IAssemblyName pName, uint dwCmpFlags);
        [PreserveSig()]
        int Clone(out IAssemblyName pName);
    }
    [ComImport(), Guid("7C23FF90-33AF-11D3-95DA-00A024A85B51"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
    interface IApplicationContext
    {
        void SetContextNameObject(IAssemblyName pName);
        void GetContextNameObject(out IAssemblyName ppName);
        void Set([MarshalAs(UnmanagedType.LPWStr)] string szName, int pvValue, uint cbValue, uint dwFlags);
        void Get([MarshalAs(UnmanagedType.LPWStr)] string szName, out int pvValue, ref uint pcbValue, uint dwFlags);
        void GetDynamicDirectory(out int wzDynamicDir, ref uint pdwSize);
    }
    [ComImport(), Guid("21B8916C-F28E-11D2-A473-00C04F8EF448"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
    interface IAssemblyEnum
    {
        [PreserveSig()]
        int GetNextAssembly(out IApplicationContext ppAppCtx, out IAssemblyName ppName, uint dwFlags);
        [PreserveSig()]
        int Reset();
        [PreserveSig()]
        int Clone(out IAssemblyEnum ppEnum);
    }
}
#else
//TODO: provide a way to query ROTOR GAC
#endif