(GH-879) Capture the editor settings and enforce file exclusions

Previously the EnumeratePSFiles method was modified to be able to use globbing
patterns to filter workspace files. This commit

* Modifies the LanguageServerSettings class to capture the 'files' and 'search'
  Settings in order to determine the correct list of glob patterns to use when
  searching.  Currently the 'files.exclude' and 'search.exclude' are merged
  together to generate the list of globs and then set the Workspace settings
  appropriately
* Uses the 'search.followSymlinks' setting to determine whether to ignore
  reparse points

Note that the LanguageClient must be configured to send these settings during
the didChangeConfiguration events otherwise it will default to include
everything.

Author: glennsarti

Diff for: src/PowerShellEditorServices.Protocol/Server/LanguageServer.cs

@@ -726,6 +726,35 @@ await this.RunScriptDiagnosticsAsync(
                     this.editorSession,
                     eventContext);
             }
+
+            // Convert the editor file glob patterns into an array for the Workspace
+            // TODO Is this thread-safe? this is hardly an atomic operation. But intermediate objects
+            // are costly. Given it's a config only change maybe a race condition won't occur?
+            editorSession.Workspace.ExcludeFilesGlob.Clear();
+            if (configChangeParams.Settings.Files != null && configChangeParams.Settings.Files.Exclude != null)
+            {
+                foreach(string pattern in configChangeParams.Settings.Files.Exclude.Keys)
+                {
+                    if (configChangeParams.Settings.Files.Exclude[pattern] && !editorSession.Workspace.ExcludeFilesGlob.Contains(pattern))
+                    {
+                        editorSession.Workspace.ExcludeFilesGlob.Add(pattern);
+                    }
+                }
+            }
+            if (configChangeParams.Settings.Search != null && configChangeParams.Settings.Search.Exclude != null)
+            {
+                foreach(string pattern in configChangeParams.Settings.Search.Exclude.Keys)
+                {
+                    if (configChangeParams.Settings.Search.Exclude[pattern] && !editorSession.Workspace.ExcludeFilesGlob.Contains(pattern))
+                    {
+                        editorSession.Workspace.ExcludeFilesGlob.Add(pattern);
+                    }
+                }
+            }
+            if (configChangeParams.Settings.Search != null && configChangeParams.Settings.Search.FollowSymlinks != null)
+            {
+                editorSession.Workspace.FollowSymlinks = configChangeParams.Settings.Search.FollowSymlinks;
+            }
         }
 
         protected async Task HandleDefinitionRequestAsync(

Diff for: src/PowerShellEditorServices.Protocol/Server/LanguageServerSettings.cs

@@ -300,12 +300,51 @@ public void Update(
         }
     }
 
-    public class LanguageServerSettingsWrapper
-        {
-            // NOTE: This property is capitalized as 'Powershell' because the
-            // mode name sent from the client is written as 'powershell' and
-            // JSON.net is using camelCasing.
+    /// <summary>
+    /// Additional settings from the Language Client that affect Language Server operations but
+    /// do not exist under the 'powershell' section
+    /// </summary>
+    public class EditorFileSettings
+    {
+        /// <summary>
+        /// Exclude files globs consists of hashtable with the key as the glob and a boolean value to indicate if the
+        /// the glob is in effect.
+        /// </summary>
+        public System.Collections.Generic.Dictionary<string, Boolean> Exclude { get; set; }
+    }
 
-            public LanguageServerSettings Powershell { get; set; }
-        }
+    /// <summary>
+    /// Additional settings from the Language Client that affect Language Server operations but
+    /// do not exist under the 'powershell' section
+    /// </summary>
+    public class EditorSearchSettings
+    {
+        /// <summary>
+        /// Exclude files globs consists of hashtable with the key as the glob and a boolean value to indicate if the
+        /// the glob is in effect.
+        /// </summary>
+        public System.Collections.Generic.Dictionary<string, Boolean> Exclude { get; set; }
+        /// <summary>
+        /// Whether to follow symlinks when searching
+        /// </summary>
+        public bool FollowSymlinks { get; set; } = true;
+    }
+
+    public class LanguageServerSettingsWrapper
+    {
+        // NOTE: This property is capitalized as 'Powershell' because the
+        // mode name sent from the client is written as 'powershell' and
+        // JSON.net is using camelCasing.
+        public LanguageServerSettings Powershell { get; set; }
+
+        // NOTE: This property is capitalized as 'Files' because the
+        // mode name sent from the client is written as 'files' and
+        // JSON.net is using camelCasing.
+        public EditorFileSettings Files { get; set; }
+
+        // NOTE: This property is capitalized as 'Search' because the
+        // mode name sent from the client is written as 'search' and
+        // JSON.net is using camelCasing.
+        public EditorSearchSettings Search { get; set; }
     }
+}