Fix discovery of capabilities WinPSAdapter

Author: Gijsreyn

powershell-adapter/Tests/win_powershellgroup.tests.ps1

@@ -373,6 +373,7 @@ class PSClassResource {
     $LASTEXITCODE | Should -Be 0
     $out.type | Should -Contain 'PSClassResource/PSClassResource'
     $out | Where-Object -Property type -EQ PSClassResource/PSClassResource | Select-Object -ExpandProperty implementedAs | Should -Be 1 # Class-based
+    ($out | Where-Object -Property type -EQ 'PSClassResource/PSClassResource').capabilities | Should -BeIn @('get', 'test', 'set', 'export')
   }
 
   It 'Get works with class-based PS DSC resources' -Skip:(!$IsWindows) {

powershell-adapter/psDscAdapter/win_psDscAdapter.psm1

@@ -1,7 +1,7 @@
 # Copyright (c) Microsoft Corporation.
 # Licensed under the MIT License.
 
-$script:CurrentCacheSchemaVersion = 1
+$script:CurrentCacheSchemaVersion = 2
 
 function Write-DscTrace {
     param(
@@ -230,6 +230,7 @@ function Invoke-DscCacheRefresh {
             if ($classBased -and ($classBased.CustomAttributes.AttributeType.Name -eq 'DscResourceAttribute')) {
                 "Detected class-based resource: $($dscResource.Name) => Type: $($classBased.BaseType.FullName)" | Write-DscTrace
                 $dscResourceInfo.ImplementationDetail = 'ClassBased'
+                $dscResourceInfo.Methods = GetClassBasedCapabilities -filePath $dscResource.Path
             }
 
             # fill in resource files (and their last-write-times) that will be used for up-do-date checks
@@ -239,10 +240,10 @@ function Invoke-DscCacheRefresh {
             }
 
             $dscResourceCacheEntries.Add([dscResourceCacheEntry]@{
-                Type            = "$moduleName/$($dscResource.Name)"
-                DscResourceInfo = $DscResourceInfo
-                LastWriteTimes  = $lastWriteTimes
-            })
+                    Type            = "$moduleName/$($dscResource.Name)"
+                    DscResourceInfo = $DscResourceInfo
+                    LastWriteTimes  = $lastWriteTimes
+                })
         }
 
         if ($namedModules.Count -gt 0) {
@@ -584,6 +585,61 @@ function ValidateMethod {
     return $method
 }
 
+function GetClassBasedCapabilities {
+    param (
+        [Parameter(Mandatory = $true)]
+        [string] $filePath
+    )
+
+    if (".psd1" -notcontains ([System.IO.Path]::GetExtension($filePath))) {
+        return @('get', 'set', 'test')
+    }
+
+    $module = $filePath.Replace('.psd1', '.psm1')
+
+    if (Test-Path $module -ErrorAction Ignore) {
+        [System.Management.Automation.Language.Token[]] $tokens = $null
+        [System.Management.Automation.Language.ParseError[]] $errors = $null
+        $ast = [System.Management.Automation.Language.Parser]::ParseFile($module, [ref]$tokens, [ref]$errors)
+        foreach ($e in $errors) {
+            $e | Out-String | Write-DscTrace -Operation Error
+        }
+
+        $typeDefinitions = $ast.FindAll(
+            {
+                $typeAst = $args[0] -as [System.Management.Automation.Language.TypeDefinitionAst]
+                return $null -ne $typeAst;
+            },
+            $false);
+
+        
+        $capabilities = @()
+        $availableMethods = @('get', 'set', 'setHandlesExist', 'whatIf', 'test', 'delete', 'export')
+        foreach ($typeDefinitionAst in $typeDefinitions) {
+            foreach ($a in $typeDefinitionAst.Attributes) {
+                if ($a.TypeName.Name -eq 'DscResource') {
+                    $methods = $typeDefinitionAst.Members | Where-Object { $_ -is [System.Management.Automation.Language.FunctionMemberAst] -and $_.Name -in $availableMethods }
+
+                    foreach ($method in $methods.Name) {
+                        # We go through each method to properly case handle the method names.
+                        switch ($method) {
+                            'Get' { $capabilities += 'get' }
+                            'Set' { $capabilities += 'set' }
+                            'Test' { $capabilities += 'test' }
+                            'WhatIf' { $capabilities += 'whatIf' }
+                            'SetHandlesExist' { $capabilities += 'setHandlesExist' }
+                            'Delete' { $capabilities += 'delete' }
+                            'Export' { $capabilities += 'export' }
+                        }
+                    }
+                }
+            }
+        }
+
+        return $capabilities
+    }
+}
+
 # cached resource
 class dscResourceCacheEntry {
     [string] $Type
@@ -626,4 +682,5 @@ class DscResourceInfo {
     [string] $ImplementedAs
     [string] $CompanyName
     [psobject[]] $Properties
+    [string[]] $Methods
 }