(GH-793) Add support for Folding Range client settings

This commit uses the the client configuration settings to modify the behaviour
of the server. In particular the Enable and ShowLastLine setting.

* The enable setting will change the provider to return null when disabled
* The ShowLastLine setting emulates the behaviour in PowerShell/vscode-powershell#1557
  * Modifies conversion method for the internal region class to FoldingRange
    object to show/hide the last line based on the extension settings
  * Modifies the tests for the default value and adds tests for the show and hide
    scenarios

Author: glennsarti

src/PowerShellEditorServices.Protocol/Server/LanguageServer.cs

@@ -1303,10 +1303,13 @@ protected Task HandleEvaluateRequest(
         private FoldingRange[] Fold(
             string documentUri)
         {
+            // TODO Should I be using dynamic registrations?
+            if (this.currentSettings.CodeFolding.Enable != true) { return null; }
             // TODO Surely there's a better way to do type adapters?
             List<FoldingRange> result = new List<FoldingRange>();
             foreach (FoldingReference fold in TokenOperations.FoldableRegions(
-                editorSession.Workspace.GetFile(documentUri).ScriptTokens))
+                editorSession.Workspace.GetFile(documentUri).ScriptTokens,
+                this.currentSettings.CodeFolding.ShowLastLine ?? this.currentSettings.CodeFolding.DefaultShowLastLine))
             {
                 FoldingRange item = new FoldingRange();
                 item.endCharacter = fold.endCharacter;

src/PowerShellEditorServices.Protocol/Server/LanguageServerSettings.cs

@@ -20,10 +20,13 @@ public class LanguageServerSettings
 
         public CodeFormattingSettings CodeFormatting { get; set; }
 
+        public CodeFoldingSettings CodeFolding { get; set; }
+
         public LanguageServerSettings()
         {
             this.ScriptAnalysis = new ScriptAnalysisSettings();
             this.CodeFormatting = new CodeFormattingSettings();
+            this.CodeFolding = new CodeFoldingSettings();
         }
 
         public void Update(
@@ -39,6 +42,7 @@ public void Update(
                     workspaceRootPath,
                     logger);
                 this.CodeFormatting = new CodeFormattingSettings(settings.CodeFormatting);
+                this.CodeFolding.Update(settings.CodeFolding, logger);
             }
         }
     }
@@ -261,6 +265,60 @@ private Hashtable GetCustomPSSASettingsHashtable(int tabSize, bool insertSpaces)
         }
     }
 
+    /// <summary>
+    /// Code folding settings
+    /// </summary>
+    public class CodeFoldingSettings
+    {
+        /// <summary>
+        /// Whether the folding is enabled
+        /// </summary>
+        public bool? Enable { get; set; }
+
+        /// <summary>
+        /// Whether to show or hide the last line of a folding region
+        /// </summary>
+        public bool? ShowLastLine { get; set; }
+
+        /// <summary>
+        /// Default value for Enable property. Default is true as per VSCode
+        /// </summary>
+        public bool DefaultEnable { get { return true; }}
+
+        /// <summary>
+        ///  Default value for ShowLastLine property. Default is true as per VSCode
+        /// </summary>
+        public bool DefaultShowLastLine { get { return true; }}
+
+        /// <summary>
+        /// Settings constructor; including the default settings.
+        /// </summary>
+        public CodeFoldingSettings()
+        {
+            this.Enable = this.DefaultEnable;
+            this.ShowLastLine = this.DefaultShowLastLine;
+        }
+
+        /// <summary>
+        /// Update these settings from another settings object
+        /// </summary>
+        public void Update(
+            CodeFoldingSettings settings,
+            ILogger logger)
+        {
+            if (settings != null) {
+                if (settings.Enable != null) {
+                    this.Enable = settings.Enable;
+                    logger.Write(LogLevel.Verbose, $"Using Code Folding Enabled - '{this.Enable.ToString()}'");
+                }
+                if (settings.ShowLastLine != null) {
+                    this.ShowLastLine = settings.ShowLastLine;
+                    logger.Write(LogLevel.Verbose, $"Using Code Folding ShowLastLine - '{this.ShowLastLine.ToString()}'");
+                }
+            }
+        }
+    }
+
     public class LanguageServerSettingsWrapper
         {
             // NOTE: This property is capitalized as 'Powershell' because the

src/PowerShellEditorServices/Language/TokenOperations.cs

@@ -18,7 +18,10 @@ internal static class TokenOperations
         /// <summary>
         /// Extracts all of the unique foldable regions in a script given the list tokens
         /// </summary>
-        static public FoldingReference[] FoldableRegions(Token[] tokens) {
+        static public FoldingReference[] FoldableRegions(
+            Token[] tokens,
+            bool ShowLastLine)
+        {
             List<FoldingReference> foldableRegions = new List<FoldingReference>();
 
             // Find matching braces { -> }
@@ -89,6 +92,12 @@ static public FoldingReference[] FoldableRegions(Token[] tokens) {
                 return (item.startLine == foldableRegions[index - 1].startLine);
             });
 
+            // Some editors have different folding UI, sometimes the lastline should be displayed
+            // If we do want to show the last line, just change the region to be one line less
+            if (ShowLastLine) {
+                foldableRegions.ForEach( item => { item.endLine--; });
+            }
+
             return foldableRegions.ToArray();
         }
 

test/PowerShellEditorServices.Test/Language/TokenOperationsTests.cs

@@ -13,13 +13,13 @@ public class TokenOperationsTests
         /// <summary>
         /// Helper methiod to create a stub script file and then call FoldableRegions
         /// </summary>
-        private FoldingReference[] GetRegions(string text) {
+        private FoldingReference[] GetRegions(string text, bool showLastLine = true) {
             ScriptFile scriptFile = new ScriptFile(
                 "testfile",
                 "clienttestfile",
                 text,
                 Version.Parse("5.0"));
-            return Microsoft.PowerShell.EditorServices.TokenOperations.FoldableRegions(scriptFile.ScriptTokens);
+            return Microsoft.PowerShell.EditorServices.TokenOperations.FoldableRegions(scriptFile.ScriptTokens, showLastLine);
         }
 
         // This PowerShell script will exercise all of the
@@ -100,21 +100,21 @@ double quoted herestrings should also fold
 $something = $true
 #endregion Comment Block 3";
         private FoldingReference[] expectedAllInOneScriptFolds = {
-            new FoldingReference(0,   0,  4, 10, "region"),
-            new FoldingReference(1,   0,  3,  2, "comment"),
-            new FoldingReference(10,  0, 15,  2, "comment"),
-            new FoldingReference(16, 30, 60,  1, null),
-            new FoldingReference(17,  0, 22,  2, "comment"),
-            new FoldingReference(23,  7, 26,  2, null),
-            new FoldingReference(28,  5, 31,  2, null),
-            new FoldingReference(35,  2, 37,  0, "comment"),
-            new FoldingReference(39,  2, 49, 14, "region"),
-            new FoldingReference(41,  4, 45, 14, "region"),
-            new FoldingReference(51,  7, 53,  3, null),
-            new FoldingReference(56,  7, 59,  3, null),
-            new FoldingReference(64,  0, 66,  0, "comment"),
-            new FoldingReference(67,  0, 72, 26, "region"),
-            new FoldingReference(68,  0, 70,  0, "comment")
+            new FoldingReference(0,   0,  3, 10, "region"),
+            new FoldingReference(1,   0,  2,  2, "comment"),
+            new FoldingReference(10,  0, 14,  2, "comment"),
+            new FoldingReference(16, 30, 59,  1, null),
+            new FoldingReference(17,  0, 21,  2, "comment"),
+            new FoldingReference(23,  7, 25,  2, null),
+            new FoldingReference(28,  5, 30,  2, null),
+            new FoldingReference(35,  2, 36,  0, "comment"),
+            new FoldingReference(39,  2, 48, 14, "region"),
+            new FoldingReference(41,  4, 44, 14, "region"),
+            new FoldingReference(51,  7, 52,  3, null),
+            new FoldingReference(56,  7, 58,  3, null),
+            new FoldingReference(64,  0, 65,  0, "comment"),
+            new FoldingReference(67,  0, 71, 26, "region"),
+            new FoldingReference(68,  0, 69,  0, "comment")
         };
 
         /// <summary>
@@ -155,6 +155,19 @@ public void LaguageServiceFindsFoldablRegionsWithCRLF() {
             AssertFoldingReferenceArrays(expectedAllInOneScriptFolds, result);
         }
 
+        [Fact]
+        public void LaguageServiceFindsFoldablRegionsWithoutLastLine() {
+            FoldingReference[] result = GetRegions(allInOneScript, false);
+            // Incrememnt the end line of the expected regions by one as we will
+            // be hiding the last line
+            FoldingReference[] expectedFolds = expectedAllInOneScriptFolds.Clone() as FoldingReference[];
+            for (int index = 0; index < expectedFolds.Length; index++)
+            {
+                expectedFolds[index].endLine++;
+            }
+            AssertFoldingReferenceArrays(expectedFolds, result);
+        }
+
         [Fact]
         public void LaguageServiceFindsFoldablRegionsWithMismatchedRegions() {
             string testString =
@@ -167,7 +180,7 @@ public void LaguageServiceFindsFoldablRegionsWithMismatchedRegions() {
 #region should not fold - mismatched
 ";
             FoldingReference[] expectedFolds = {
-                new FoldingReference(2, 0, 4, 10, "region")
+                new FoldingReference(2, 0, 3, 10, "region")
             };
 
             FoldingReference[] result = GetRegions(testString);
@@ -184,8 +197,8 @@ public void LaguageServiceFindsFoldablRegionsWithDuplicateRegions() {
 })
 ";
             FoldingReference[] expectedFolds = {
-                new FoldingReference(1, 64, 2, 27, null),
-                new FoldingReference(2, 35, 4,  2, null)
+                new FoldingReference(1, 64, 1, 27, null),
+                new FoldingReference(2, 35, 3,  2, null)
             };
 
             FoldingReference[] result = GetRegions(testString);