Support SignatureHelp

src/PowerShellEditorServices.Engine/LanguageServer/OmnisharpLanguageServer.cs

@@ -112,6 +112,7 @@ public async Task StartAsync()
                     .WithHandler<InvokeExtensionCommandHandler>()
                     .WithHandler<CompletionHandler>()
                     .WithHandler<HoverHandler>()
+                    .WithHandler<SignatureHelpHandler>()
                     .OnInitialize(
                         async (languageServer, request) =>
                         {

src/PowerShellEditorServices.Engine/Services/Symbols/ParameterSetSignatures.cs

@@ -0,0 +1,151 @@
+//
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+//
+
+using System.Collections.Generic;
+using System.Management.Automation;
+using Microsoft.PowerShell.EditorServices.Symbols;
+
+namespace Microsoft.PowerShell.EditorServices
+{
+    /// <summary>
+    /// A class for containing the commandName, the command's
+    /// possible signatures, and the script extent of the command
+    /// </summary>
+    public class ParameterSetSignatures
+    {
+        #region Properties
+        /// <summary>
+        /// Gets the name of the command
+        /// </summary>
+        public string CommandName { get; internal set; }
+
+        /// <summary>
+        /// Gets the collection of signatures for the command
+        /// </summary>
+        public ParameterSetSignature[] Signatures { get; internal set; }
+
+        /// <summary>
+        /// Gets the script extent of the command
+        /// </summary>
+        public ScriptRegion ScriptRegion { get; internal set; }
+        #endregion
+
+        /// <summary>
+        /// Constructs an instance of a ParameterSetSignatures object
+        /// </summary>
+        /// <param name="commandInfoSet">Collection of parameter set info</param>
+        /// <param name="foundSymbol"> The SymbolReference of the command</param>
+        public ParameterSetSignatures(IEnumerable<CommandParameterSetInfo> commandInfoSet, SymbolReference foundSymbol)
+        {
+            List<ParameterSetSignature> paramSetSignatures = new List<ParameterSetSignature>();
+            foreach (CommandParameterSetInfo setInfo in commandInfoSet)
+            {
+                paramSetSignatures.Add(new ParameterSetSignature(setInfo));
+            }
+            Signatures = paramSetSignatures.ToArray();
+            CommandName = foundSymbol.ScriptRegion.Text;
+            ScriptRegion = foundSymbol.ScriptRegion;
+        }
+    }
+
+    /// <summary>
+    /// A class for containing the signature text and the collection of parameters for a signature
+    /// </summary>
+    public class ParameterSetSignature
+    {
+        private static HashSet<string> commonParameterNames =
+            new HashSet<string>
+            {
+                "Verbose",
+                "Debug",
+                "ErrorAction",
+                "WarningAction",
+                "InformationAction",
+                "ErrorVariable",
+                "WarningVariable",
+                "InformationVariable",
+                "OutVariable",
+                "OutBuffer",
+                "PipelineVariable",
+            };
+
+        #region Properties
+        /// <summary>
+        /// Gets the signature text
+        /// </summary>
+        public string SignatureText { get; internal set; }
+
+        /// <summary>
+        /// Gets the collection of parameters for the signature
+        /// </summary>
+        public IEnumerable<ParameterInfo> Parameters { get; internal set; }
+        #endregion
+
+        /// <summary>
+        /// Constructs an instance of a ParameterSetSignature
+        /// </summary>
+        /// <param name="commandParamInfoSet">Collection of parameter info</param>
+        public ParameterSetSignature(CommandParameterSetInfo commandParamInfoSet)
+        {
+            List<ParameterInfo> parameterInfo = new List<ParameterInfo>();
+            foreach (CommandParameterInfo commandParameterInfo in commandParamInfoSet.Parameters)
+            {
+                if (!commonParameterNames.Contains(commandParameterInfo.Name))
+                {
+                    parameterInfo.Add(new ParameterInfo(commandParameterInfo));
+                }
+            }
+
+            SignatureText = commandParamInfoSet.ToString();
+            Parameters = parameterInfo.ToArray();
+        }
+    }
+
+    /// <summary>
+    /// A class for containing the parameter info of a parameter
+    /// </summary>
+    public class ParameterInfo
+    {
+        #region Properties
+        /// <summary>
+        /// Gets the name of the parameter
+        /// </summary>
+        public string Name { get; internal set; }
+
+        /// <summary>
+        /// Gets the type of the parameter
+        /// </summary>
+        public string ParameterType { get; internal set; }
+
+        /// <summary>
+        /// Gets the position of the parameter
+        /// </summary>
+        public int Position { get; internal set; }
+
+        /// <summary>
+        /// Gets a boolean for whetheer or not the parameter is required
+        /// </summary>
+        public bool IsMandatory { get; internal set; }
+
+        /// <summary>
+        /// Gets the help message of the parameter
+        /// </summary>
+        public string HelpMessage { get; internal set; }
+        #endregion
+
+        /// <summary>
+        /// Constructs an instance of a ParameterInfo object
+        /// </summary>
+        /// <param name="parameterInfo">Parameter info of the parameter</param>
+        public ParameterInfo(CommandParameterInfo parameterInfo)
+        {
+            this.Name = "-" + parameterInfo.Name;
+            this.ParameterType = parameterInfo.ParameterType.FullName;
+            this.Position = parameterInfo.Position;
+            this.IsMandatory = parameterInfo.IsMandatory;
+            this.HelpMessage = parameterInfo.HelpMessage;
+        }
+    }
+}

src/PowerShellEditorServices.Engine/Services/Symbols/SymbolsService.cs

@@ -7,6 +7,7 @@
 using System.Collections.Generic;
 using System.Collections.Specialized;
 using System.Linq;
+using System.Management.Automation;
 using System.Runtime.InteropServices;
 using System.Threading.Tasks;
 using Microsoft.Extensions.Logging;
@@ -262,5 +263,62 @@ public async Task<SymbolDetails> FindSymbolDetailsAtLocationAsync(
 
             return symbolDetails;
         }
+
+        /// <summary>
+        /// Finds the parameter set hints of a specific command (determined by a given file location)
+        /// </summary>
+        /// <param name="file">The details and contents of a open script file</param>
+        /// <param name="lineNumber">The line number of the cursor for the given script</param>
+        /// <param name="columnNumber">The coulumn number of the cursor for the given script</param>
+        /// <returns>ParameterSetSignatures</returns>
+        public async Task<ParameterSetSignatures> FindParameterSetsInFileAsync(
+            ScriptFile file,
+            int lineNumber,
+            int columnNumber,
+            PowerShellContextService powerShellContext)
+        {
+            SymbolReference foundSymbol =
+                AstOperations.FindCommandAtPosition(
+                    file.ScriptAst,
+                    lineNumber,
+                    columnNumber);
+
+            if (foundSymbol == null)
+            {
+                return null;
+            }
+
+            CommandInfo commandInfo =
+                await CommandHelpers.GetCommandInfoAsync(
+                    foundSymbol.SymbolName,
+                    powerShellContext);
+
+            if (commandInfo == null)
+            {
+                return null;
+            }
+
+            try
+            {
+                IEnumerable<CommandParameterSetInfo> commandParamSets = commandInfo.ParameterSets;
+                return new ParameterSetSignatures(commandParamSets, foundSymbol);
+            }
+            catch (RuntimeException e)
+            {
+                // A RuntimeException will be thrown when an invalid attribute is
+                // on a parameter binding block and then that command/script has
+                // its signatures resolved by typing it into a script.
+                _logger.LogException("RuntimeException encountered while accessing command parameter sets", e);
+
+                return null;
+            }
+            catch (InvalidOperationException)
+            {
+                // For some commands there are no paramsets (like applications).  Until
+                // the valid command types are better understood, catch this exception
+                // which gets raised when there are no ParameterSets for the command type.
+                return null;
+            }
+        }
     }
 }

src/PowerShellEditorServices.Engine/Services/TextDocument/Handlers/SignatureHelpHandler.cs

@@ -0,0 +1,116 @@
+//
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+//
+
+using System.Linq;
+using System.Threading;
+using System.Threading.Tasks;
+using Microsoft.Extensions.Logging;
+using Microsoft.PowerShell.EditorServices;
+using OmniSharp.Extensions.LanguageServer.Protocol.Client.Capabilities;
+using OmniSharp.Extensions.LanguageServer.Protocol.Models;
+using OmniSharp.Extensions.LanguageServer.Protocol.Server;
+
+namespace PowerShellEditorServices.Engine.Services.Handlers
+{
+    public class SignatureHelpHandler : ISignatureHelpHandler
+    {
+        private static readonly SignatureInformation[] s_emptySignatureResult = new SignatureInformation[0];
+
+        private readonly DocumentSelector _documentSelector = new DocumentSelector(
+            new DocumentFilter()
+            {
+                Pattern = "**/*.ps*1"
+            }
+        );
+
+        private readonly ILogger _logger;
+        private readonly SymbolsService _symbolsService;
+        private readonly WorkspaceService _workspaceService;
+        private readonly PowerShellContextService _powerShellContextService;
+
+        private SignatureHelpCapability _capability;
+
+        public SignatureHelpHandler(
+            ILoggerFactory factory,
+            SymbolsService symbolsService,
+            WorkspaceService workspaceService,
+            PowerShellContextService powerShellContextService)
+        {
+            _logger = factory.CreateLogger<HoverHandler>();
+            _symbolsService = symbolsService;
+            _workspaceService = workspaceService;
+            _powerShellContextService = powerShellContextService;
+        }
+
+        public SignatureHelpRegistrationOptions GetRegistrationOptions()
+        {
+            return new SignatureHelpRegistrationOptions
+            {
+                DocumentSelector = _documentSelector,
+                // A sane default of " ". We may be able to include others like "-".
+                TriggerCharacters = new Container<string>(" ")
+            };
+        }
+
+        public async Task<SignatureHelp> Handle(SignatureHelpParams request, CancellationToken cancellationToken)
+        {
+            ScriptFile scriptFile =
+                _workspaceService.GetFile(
+                    request.TextDocument.Uri.ToString());
+
+            ParameterSetSignatures parameterSets =
+                await _symbolsService.FindParameterSetsInFileAsync(
+                    scriptFile,
+                    (int) request.Position.Line + 1,
+                    (int) request.Position.Character + 1,
+                    _powerShellContextService);
+
+            SignatureInformation[] signatures = s_emptySignatureResult;
+
+            if (parameterSets != null)
+            {
+                signatures = new SignatureInformation[parameterSets.Signatures.Length];
+                for (int i = 0; i < signatures.Length; i++)
+                {
+                    var parameters = new ParameterInformation[parameterSets.Signatures[i].Parameters.Count()];
+                    int j = 0;
+                    foreach (ParameterInfo param in parameterSets.Signatures[i].Parameters)
+                    {
+                        parameters[j] = CreateParameterInfo(param);
+                        j++;
+                    }
+
+                    signatures[i] = new SignatureInformation
+                    {
+                        Label = parameterSets.CommandName + " " + parameterSets.Signatures[i].SignatureText,
+                        Documentation = null,
+                        Parameters = parameters,
+                    };
+                }
+            }
+
+            return new SignatureHelp
+            {
+                Signatures = signatures,
+                ActiveParameter = null,
+                ActiveSignature = 0
+            };
+        }
+
+        public void SetCapability(SignatureHelpCapability capability)
+        {
+            _capability = capability;
+        }
+
+        private static ParameterInformation CreateParameterInfo(ParameterInfo parameterInfo)
+        {
+            return new ParameterInformation
+            {
+                Label = parameterInfo.Name,
+                Documentation = string.Empty
+            };
+        }
+    }
+}

test/PowerShellEditorServices.Test.E2E/LanguageServerProtocolMessageTests.cs

@@ -1,4 +1,9 @@
-using System;
+//
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+//
+
+using System;
 using System.Collections.Generic;
 using System.Diagnostics;
 using System.IO;
@@ -664,5 +669,28 @@ public async Task CanSendHoverRequest()
                     Assert.Equal("Writes customized output to a host.", str2.Value);
                 });
         }
+
+        [Fact]
+        public async Task CanSendSignatureHelpRequest()
+        {
+            string filePath = NewTestFile("Get-Date ");
+
+            SignatureHelp signatureHelp = await LanguageClient.SendRequest<SignatureHelp>(
+                "textDocument/signatureHelp",
+                new SignatureHelpParams
+                {
+                    TextDocument = new TextDocumentIdentifier
+                    {
+                        Uri = new Uri(filePath)
+                    },
+                    Position = new Position
+                    {
+                        Line = 0,
+                        Character = 9
+                    }
+                });
+
+            Assert.Contains("Get-Date", signatureHelp.Signatures.First().Label);
+        }
     }
 }