SubSystem work 1

src/DscSubsystem/CrossPlatformDsc.cs

@@ -0,0 +1,92 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
+#nullable enable
+
+using System;
+using System.Collections.ObjectModel;
+using System.Collections.Generic;
+using System.Management.Automation;
+using System.Management.Automation.Internal;
+using System.Management.Automation.Language;
+
+namespace System.Management.Automation.Subsystem
+{
+    /// <summary>
+    /// Interface for implementing a cross platform desired state configuration component.
+    /// </summary>
+    public class CrossPlatformDsc : ICrossPlatformDsc, IModuleAssemblyInitializer
+    {
+        /// <summary>
+        /// Gets the unique identifier for a subsystem implementation.
+        /// </summary>
+        public Guid Id { get {return Guid.NewGuid();} }
+
+        /// <summary>
+        /// Gets the name of a subsystem implementation.
+        /// </summary>
+        public string Name { get {return "Cross platform desired state configuration";} }
+
+        /// <summary>
+        /// Gets the description of a subsystem implementation.
+        /// </summary>
+        public string Description { get {return "Cross platform desired state configuration";} }
+
+        /// <summary>
+        /// Gets a dictionary that contains the functions to be defined at the global scope of a PowerShell session.
+        /// Key: function name; Value: function script.
+        /// </summary>
+        Dictionary<string, string>? ISubsystem.FunctionsToDefine => null;
+
+        /// <summary>
+        /// Test.
+        /// </summary>
+        public void LoadDefaultCimKeywords(Collection<Exception> errors)
+        {
+            Microsoft.PowerShell.DesiredStateConfiguration.Internal.CrossPlatform.DscClassCache.LoadDefaultCimKeywords(errors);
+        }
+
+        /// <summary>
+        /// Default summary.
+        /// </summary>
+        public void ClearCache()
+        {
+            Microsoft.PowerShell.DesiredStateConfiguration.Internal.CrossPlatform.DscClassCache.ClearCache();
+        }
+
+        /// <summary>
+        /// Default summary.
+        /// </summary>
+        public bool NewApiIsUsed
+        {
+            get
+            {
+                return Microsoft.PowerShell.DesiredStateConfiguration.Internal.CrossPlatform.DscClassCache.NewApiIsUsed;
+            }
+        }
+
+        /// <summary>
+        /// Default summary.
+        /// </summary>
+        public string GetDSCResourceUsageString(DynamicKeyword keyword)
+        {
+            return Microsoft.PowerShell.DesiredStateConfiguration.Internal.CrossPlatform.DscClassCache.GetDSCResourceUsageString(keyword);
+        }
+
+        /// <summary>
+        /// Test.
+        /// </summary>
+        public void RegisterSubsystemIfNotAlready()
+        {
+            if (SubsystemManager.GetSubsystem<ICrossPlatformDsc>() == null)
+            {
+                SubsystemManager.RegisterSubsystem(SubsystemKind.CrossPlatformDsc, this);
+            }
+        }
+
+        public void OnImport()
+        {
+            RegisterSubsystemIfNotAlready();
+        }
+    }
+}

src/DscSubsystem/JsonCimDSCParser.cs

@@ -0,0 +1,68 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
+using System;
+using System.Collections;
+using System.Collections.Generic;
+using System.Diagnostics.CodeAnalysis;
+using System.Globalization;
+using System.IO;
+using System.Management.Automation;
+using System.Security;
+
+namespace Microsoft.PowerShell.DesiredStateConfiguration.Internal.CrossPlatform
+{
+    /// <summary>
+    /// Class that does high level Cim schema parsing.
+    /// </summary>
+    internal class CimDSCParser
+    {
+        private readonly JsonDeserializer _jsonDeserializer;
+        
+        internal CimDSCParser()
+        {
+            _jsonDeserializer = JsonDeserializer.Create();
+        }
+
+        internal IEnumerable<PSObject> ParseSchemaJson(string filePath, bool useNewRunspace = false)
+        {
+            try
+            {
+                string json = File.ReadAllText(filePath);
+                string fileNameDefiningClass = Path.GetFileNameWithoutExtension(filePath);
+                int dotIndex = fileNameDefiningClass.IndexOf(".schema", StringComparison.InvariantCultureIgnoreCase);
+                if (dotIndex != -1)
+                {
+                    fileNameDefiningClass = fileNameDefiningClass.Substring(0, dotIndex);
+                }
+
+                IEnumerable<PSObject> result = _jsonDeserializer.DeserializeClasses(json, useNewRunspace);
+                foreach (dynamic classObject in result)
+                {
+                    string superClassName = classObject.SuperClassName;
+                    string className = classObject.ClassName;
+                    if (string.Equals(superClassName, "OMI_BaseResource", StringComparison.OrdinalIgnoreCase))
+                    {
+                        // Get the name of the file without schema.mof/json extension
+                        if (!className.Equals(fileNameDefiningClass, StringComparison.OrdinalIgnoreCase))
+                        {
+                            PSInvalidOperationException e = PSTraceSource.NewInvalidOperationException(
+                                ParserStrings.ClassNameNotSameAsDefiningFile, className, fileNameDefiningClass);
+                            throw e;
+                        }
+                    }
+                }
+
+                return result;
+            }
+            catch (Exception exception)
+            {
+                PSInvalidOperationException e = PSTraceSource.NewInvalidOperationException(
+                    exception, ParserStrings.CimDeserializationError, filePath);
+
+                e.SetErrorId("CimDeserializationError");
+                throw e;
+            }
+        }
+    }
+}

src/DscSubsystem/JsonDeserializer.cs

@@ -0,0 +1,72 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
+using System;
+using System.Collections;
+using System.Collections.Generic;
+using System.Management.Automation;
+using System.Management.Automation.Runspaces;
+
+namespace Microsoft.PowerShell.DesiredStateConfiguration.Internal.CrossPlatform
+{
+    internal class JsonDeserializer
+    {
+        #region Constructors
+
+        /// <summary>
+        /// Instantiates a default deserializer.
+        /// </summary>
+        /// <returns>Default deserializer.</returns>
+        public static JsonDeserializer Create()
+        {
+            return new JsonDeserializer();
+        }
+
+        #endregion Constructors
+
+        #region Methods
+
+        /// <summary>
+        /// Returns schema of Cim classes from specified json file.
+        /// </summary>
+        /// <param name="json">Json text to deserialize.</param>
+        /// <param name="useNewRunspace">If a new runspace should be used.</param>
+        /// <returns>Deserialized PSObjects.</returns>
+        public IEnumerable<PSObject> DeserializeClasses(string json, bool useNewRunspace = false)
+        {
+            if (string.IsNullOrEmpty(json))
+            {
+                throw new ArgumentNullException(nameof(json));
+            }
+
+            System.Management.Automation.PowerShell powerShell = null;
+
+            if (useNewRunspace)
+            {
+                // currently using RunspaceMode.NewRunspace will reset PSModulePath env var for the entire process
+                // this is something we want to avoid in DSC GuestConfigAgent scenario, so we use following workaround
+                var s_iss = InitialSessionState.CreateDefault();
+                s_iss.EnvironmentVariables.Add(
+                    new SessionStateVariableEntry(
+                        "PSModulePath",
+                        Environment.GetEnvironmentVariable("PSModulePath"),
+                        description: null));
+                powerShell = System.Management.Automation.PowerShell.Create(s_iss);
+            }
+            else
+            {
+                powerShell = System.Management.Automation.PowerShell.Create(RunspaceMode.CurrentRunspace);
+            }
+
+            using (powerShell)
+            {
+                return powerShell.AddCommand("Microsoft.PowerShell.Utility\\ConvertFrom-Json")
+                    .AddParameter("InputObject", json)
+                    .AddParameter("Depth", 100) // maximum supported by cmdlet
+                    .Invoke();
+            }
+        }
+
+        #endregion Methods
+    }
+}

src/DscSubsystem/Microsoft.PowerShell.DscSubsystem.csproj

@@ -0,0 +1,15 @@
+<Project Sdk="Microsoft.NET.Sdk" ToolsVersion="15.0">
+  <PropertyGroup>
+    <TargetFramework>net6.0</TargetFramework>
+    <AssemblyName>Microsoft.PowerShell.DscSubsystem</AssemblyName>
+    
+    <DelaySign>true</DelaySign>
+    <AssemblyOriginatorKeyFile>visualstudiopublic.snk</AssemblyOriginatorKeyFile>
+    <SignAssembly>true</SignAssembly>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <Reference Include="C:\anmenaga-PowerShell\src\powershell-win-core\bin\Debug\net6.0\win7-x64\publish\System.Management.Automation.dll"></Reference>
+  </ItemGroup>
+  
+</Project>

src/PSDesiredStateConfiguration/PSDesiredStateConfiguration.psd1

@@ -48,7 +48,7 @@ PowerShellVersion = '7.1'
 # ProcessorArchitecture = ''
 
 # Modules that must be imported into the global environment prior to importing this module
-# RequiredModules = @()
+ #RequiredModules = @()
 
 # Assemblies that must be loaded prior to importing this module
 # RequiredAssemblies = @()
@@ -63,7 +63,7 @@ PowerShellVersion = '7.1'
 # FormatsToProcess = @()
 
 # Modules to import as nested modules of the module specified in RootModule/ModuleToProcess
-# NestedModules = @()
+ NestedModules = @('Microsoft.PowerShell.DscSubsystem.dll')
 
 # Functions to export from this module, for best performance, do not use wildcards and do not delete the entry, use an empty array if there are no functions to export.
 FunctionsToExport = @(