(OmniSharpGH-1205) Adds support for code actions in .cake files

-Fixes OmniSharp#1205

src/OmniSharp.Cake/Extensions/ResponseExtensions.cs

@@ -7,6 +7,7 @@
 using OmniSharp.Models.Navigate;
 using OmniSharp.Models.MembersTree;
 using OmniSharp.Models.Rename;
+using OmniSharp.Models.V2;
 
 namespace OmniSharp.Cake.Extensions
 {
@@ -85,6 +86,44 @@ public static async Task<RenameResponse> TranslateAsync(this RenameResponse resp
             return response;
         }
 
+        public static async Task<RunCodeActionResponse> TranslateAsync(this RunCodeActionResponse response, OmniSharpWorkspace workspace)
+        {
+            if (response?.Changes == null)
+            {
+                return response;
+            }
+
+            var fileOperations = new List<FileOperationResponse>();
+            var changes = new Dictionary<string, List<LinePositionSpanTextChange>>();
+
+            foreach (var fileOperation in response.Changes)
+            {
+                if (fileOperation.ModificationType == FileModificationType.Modified &&
+                    fileOperation is ModifiedFileResponse modifiedFile)
+                {
+                    await PopulateModificationsAsync(modifiedFile, workspace, changes);
+                }
+
+                fileOperations.Add(fileOperation);
+            }
+
+            foreach (var change in changes)
+            {
+
+                if (!(fileOperations.FirstOrDefault(x => x.FileName == change.Key &&
+                                                         x.ModificationType == FileModificationType.Modified)
+                    is ModifiedFileResponse modifiedFile))
+                {
+                    continue;
+                }
+
+                modifiedFile.Changes = change.Value;
+            }
+
+            response.Changes = fileOperations;
+            return response;
+        }
+
         private static async Task<FileMemberElement> TranslateAsync(this FileMemberElement element, OmniSharpWorkspace workspace, Request request)
         {
             element.Location = await element.Location.TranslateAsync(workspace, request);

src/OmniSharp.Cake/Services/RequestHandlers/CakeRequestHandler.cs

@@ -61,7 +61,7 @@ public virtual async Task<TResponse> Handle(TRequest request)
             return await TranslateResponse(response, request);
         }
 
-        public virtual bool IsValid(TRequest request) => true;
+        protected virtual bool IsValid(TRequest request) => true;
 
         protected virtual async Task<TRequest> TranslateRequestAsync(TRequest req)
         {

src/OmniSharp.Cake/Services/RequestHandlers/Diagnostics/CodeCheckHandler.cs

@@ -20,7 +20,7 @@ public CodeCheckHandler(
         {
         }
 
-        public override bool IsValid(CodeCheckRequest request) =>
+        protected override bool IsValid(CodeCheckRequest request) =>
             !string.IsNullOrEmpty(request.FileName);
 
         protected override Task<QuickFixResponse> TranslateResponse(QuickFixResponse response, CodeCheckRequest request)

src/OmniSharp.Cake/Services/RequestHandlers/Refactoring/V2/BaseCodeActionHandler.cs

@@ -0,0 +1,32 @@
+using System.Composition;
+using System.Threading.Tasks;
+using OmniSharp.Cake.Utilities;
+using OmniSharp.Mef;
+using OmniSharp.Models.V2;
+
+namespace OmniSharp.Cake.Services.RequestHandlers.Refactoring.V2
+{
+    public abstract class BaseCodeActionsHandler<TRequest, TResponse> : CakeRequestHandler<TRequest, TResponse>
+        where TRequest : ICodeActionRequest
+    {
+        protected BaseCodeActionsHandler(
+            OmniSharpWorkspace workspace)
+            : base(workspace)
+        {
+        }
+
+        protected override async Task<TRequest> TranslateRequestAsync(TRequest request)
+        {
+            if (request.Selection != null)
+            {
+                var startLine = await LineIndexHelper.TranslateToGenerated(request.FileName, request.Selection.Start.Line, Workspace);
+                request.Selection.End.Line = request.Selection.Start.Line != request.Selection.End.Line
+                    ? await LineIndexHelper.TranslateToGenerated(request.FileName, request.Selection.End.Line, Workspace)
+                    : startLine;
+                request.Selection.Start.Line = startLine;
+            }
+
+            return await base.TranslateRequestAsync(request);
+        }
+    }
+}

src/OmniSharp.Cake/Services/RequestHandlers/Refactoring/V2/GetCodeActionsHandler.cs

@@ -1,17 +1,37 @@
 using System.Composition;
+using System.Linq;
+using System.Threading.Tasks;
+using OmniSharp.Cake.Utilities;
 using OmniSharp.Mef;
 using OmniSharp.Models.V2;
 
 namespace OmniSharp.Cake.Services.RequestHandlers.Refactoring.V2
 {
     [OmniSharpHandler(OmniSharpEndpoints.V2.GetCodeActions, Constants.LanguageNames.Cake), Shared]
-    public class GetCodeActionsHandler : CakeRequestHandler<GetCodeActionsRequest, GetCodeActionsResponse>
+    public class GetCodeActionsHandler : BaseCodeActionsHandler<GetCodeActionsRequest, GetCodeActionsResponse>
     {
         [ImportingConstructor]
         public GetCodeActionsHandler(
             OmniSharpWorkspace workspace) 
             : base(workspace)
         {
         }
+
+        protected override Task<GetCodeActionsResponse> TranslateResponse(GetCodeActionsResponse response, GetCodeActionsRequest request)
+        {
+            if (response?.CodeActions == null)
+            {
+                return Task.FromResult(response);
+            }
+
+            // At this point, we remove the "Rename file to.." code actions as these will
+            // return the buffer as known to Roslyn to the client. Currently we don't store
+            // the buffer as seen by the client and it's next to impossible to reverse it.
+            response.CodeActions = response.CodeActions
+                .Where(x => !x.Identifier.StartsWith("Rename file to"))
+                .ToList();
+
+            return Task.FromResult(response);
+        }
     }
 }

src/OmniSharp.Cake/Services/RequestHandlers/Refactoring/V2/RunCodeActionsHandler.cs

@@ -0,0 +1,29 @@
+using System.Collections.Generic;
+using System.Composition;
+using System.Threading.Tasks;
+using OmniSharp.Cake.Extensions;
+using OmniSharp.Mef;
+using OmniSharp.Models;
+using OmniSharp.Models.FileOpen;
+using OmniSharp.Models.V2;
+
+namespace OmniSharp.Cake.Services.RequestHandlers.Refactoring.V2
+{
+    [OmniSharpHandler(OmniSharpEndpoints.V2.RunCodeAction, Constants.LanguageNames.Cake), Shared]
+    public class RunCodeActionsHandler : BaseCodeActionsHandler<RunCodeActionRequest, RunCodeActionResponse>
+    {
+        [ImportingConstructor]
+        public RunCodeActionsHandler(
+            OmniSharpWorkspace workspace)
+            : base(workspace)
+        {
+        }
+
+        protected override bool IsValid(RunCodeActionRequest request) => request.WantsTextChanges;
+
+        protected override Task<RunCodeActionResponse> TranslateResponse(RunCodeActionResponse response, RunCodeActionRequest request)
+        {
+            return response.TranslateAsync(Workspace);
+        }
+    }
+}