Introduce configuration for "Go to Symbol in Workspace"

src/OmniSharp.Abstractions/Models/v1/FindSymbols/FindSymbolsRequest.cs

@@ -7,5 +7,7 @@ public class FindSymbolsRequest : IRequest
     {
         public string Language { get; set; }
         public string Filter { get; set; }
+        public int MinFilterLength { get; set; }
+        public int MaxItemsToReturn { get; set; }
     }
 }

src/OmniSharp.Cake/Services/RequestHandlers/Navigation/FindSymbolsHandler.cs

@@ -21,12 +21,18 @@ public FindSymbolsHandler(OmniSharpWorkspace workspace)
 
         public override Task<QuickFixResponse> Handle(FindSymbolsRequest request)
         {
+            if (request != null && request.Filter != null && request.Filter.Length < request.MinFilterLength)
+            {
+                return Task.FromResult(new QuickFixResponse { QuickFixes = Array.Empty<QuickFix>() });
+            }
+
             Func<string, bool> isMatch =
                 candidate => request != null
                 ? candidate.IsValidCompletionFor(request.Filter)
                 : true;
 
-            return Workspace.CurrentSolution.FindSymbols(isMatch, LanguageNames.Cake);
+            int maxItemsToReturn = request == null ? 0 : request.MaxItemsToReturn;
+            return Workspace.CurrentSolution.FindSymbols(isMatch, LanguageNames.Cake, maxItemsToReturn);
         }
 
         protected override Task<QuickFixResponse> TranslateResponse(QuickFixResponse response, FindSymbolsRequest request)

src/OmniSharp.Roslyn.CSharp/Services/Navigation/FindSymbolsService.cs

@@ -23,13 +23,19 @@ public FindSymbolsService(OmniSharpWorkspace workspace)
 
         public async Task<QuickFixResponse> Handle(FindSymbolsRequest request = null)
         {
+            if (request != null && request.Filter != null && request.Filter.Length < request.MinFilterLength)
+            {
+                return new QuickFixResponse { QuickFixes = Array.Empty<QuickFix>() };
+            }
+
             Func<string, bool> isMatch =
                 candidate => request != null
                 ? candidate.IsValidCompletionFor(request.Filter)
                 : true;
 
-            var csprojSymbols = await _workspace.CurrentSolution.FindSymbols(isMatch, ".csproj");
-            var projectJsonSymbols = await _workspace.CurrentSolution.FindSymbols(isMatch, ".json");
+            int maxItemsToReturn = request == null ? 0 : request.MaxItemsToReturn;
+            var csprojSymbols = await _workspace.CurrentSolution.FindSymbols(isMatch, ".csproj", maxItemsToReturn);
+            var projectJsonSymbols = await _workspace.CurrentSolution.FindSymbols(isMatch, ".json", maxItemsToReturn);
             return new QuickFixResponse()
             {
                 QuickFixes = csprojSymbols.QuickFixes.Concat(projectJsonSymbols.QuickFixes)

src/OmniSharp.Roslyn/Extensions/SolutionExtensions.cs

@@ -12,7 +12,8 @@ public static class SolutionExtensions
     {
         public static async Task<QuickFixResponse> FindSymbols(this Solution solution,
             Func<string, bool> predicate,
-            string projectFileExtension)
+            string projectFileExtension,
+            int maxItemsToReturn)
         {
             var projects = solution.Projects.Where(p =>
                 (p.FilePath?.EndsWith(projectFileExtension, StringComparison.OrdinalIgnoreCase) ?? false) ||
@@ -37,12 +38,27 @@ public static async Task<QuickFixResponse> FindSymbols(this Solution solution,
                     {
                         symbolLocations.Add(ConvertSymbol(solution, symbol, location));
                     }
+
+                    if (ShouldStopSearching(maxItemsToReturn, symbolLocations))
+                    {
+                        break;
+                    }
+                }
+
+                if (ShouldStopSearching(maxItemsToReturn, symbolLocations))
+                {
+                    break;
                 }
             }
 
             return new QuickFixResponse(symbolLocations.Distinct().ToList());
         }
 
+        private static bool ShouldStopSearching(int maxItemsToReturn, List<QuickFix> symbolLocations)
+        {
+            return maxItemsToReturn > 0 && symbolLocations.Count >= maxItemsToReturn;
+        }
+
         private static QuickFix ConvertSymbol(Solution solution, ISymbol symbol, Location location)
         {
             var lineSpan = location.GetLineSpan();

tests/OmniSharp.Cake.Tests/FindSymbolsFacts.cs

@@ -1,4 +1,5 @@
-using System.Threading.Tasks;
+using System.Linq;
+using System.Threading.Tasks;
 using Microsoft.Extensions.Logging;
 using OmniSharp.Cake.Services.RequestHandlers.Navigation;
 using OmniSharp.Models;
@@ -23,25 +24,41 @@ public FindSymbolsFacts(ITestOutputHelper testOutput) : base(testOutput)
         [Fact]
         public async Task ShouldFindSymbolsInCakeProjects()
         {
-            var symbols = await FindSymbols("CakeProject");
+            var symbols = await FindSymbols("CakeProject", 0, 0);
             Assert.NotEmpty(symbols.QuickFixes);
         }
 
+        [Fact]
+        public async Task ShouldNotFindSymbolsInCakeProjectsDueToEmptyFilter()
+        {
+            var symbols = await FindSymbols("CakeProject", 1, 0);
+            Assert.Empty(symbols.QuickFixes);
+        }
+
+        [Fact]
+        public async Task ShouldFindLimitedNumberOfSymbolsInCakeProjects()
+        {
+            var symbols = await FindSymbols("CakeProject", 0, 100);
+            Assert.Equal(100, symbols.QuickFixes.Count());
+        }
+
         [Fact]
         public async Task ShouldNotFindSymbolsInCSharpProjects()
         {
-            var symbols = await FindSymbols("ProjectAndSolution");
+            var symbols = await FindSymbols("ProjectAndSolution", 0, 0);
             Assert.Empty(symbols.QuickFixes);
         }
 
-        private async Task<QuickFixResponse> FindSymbols(string projectName)
+        private async Task<QuickFixResponse> FindSymbols(string projectName, int minFilterLength, int maxItemsToReturn)
         {
             using (var testProject = await TestAssets.Instance.GetTestProjectAsync(projectName, shadowCopy : false))
             using (var host = CreateOmniSharpHost(testProject.Directory))
             {
                 var request = new FindSymbolsRequest
                 {
-                    Filter = ""
+                    Filter = "",
+                    MinFilterLength = minFilterLength,
+                    MaxItemsToReturn = maxItemsToReturn
                 };
 
                 var requestHandler = GetRequestHandler(host);

tests/OmniSharp.Roslyn.CSharp.Tests/FindSymbolsFacts.cs

@@ -215,7 +215,7 @@ private string NestedMethod() {}
                     }
                 }";
 
-            var usages = await FindSymbolsWithFilterAsync(code, "meth");
+            var usages = await FindSymbolsWithFilterAsync(code, "meth", 0, 0);
             var symbols = usages.QuickFixes.Select(q => q.Text);
 
             var expected = new[]
@@ -240,7 +240,7 @@ public interface IConfigurationOptions { }
                     public class ConfigurationOptions : IConfigurationOptions { }
                 }";
 
-            var usages = await FindSymbolsWithFilterAsync(code, "opti");
+            var usages = await FindSymbolsWithFilterAsync(code, "opti", 0, 0);
             var symbols = usages.QuickFixes.Select(q => q.Text);
 
             var expected = new[]
@@ -253,6 +253,37 @@ public class ConfigurationOptions : IConfigurationOptions { }
             Assert.Equal(expected, symbols);
         }
 
+        [Fact]
+        public async Task no_symbols_returned_when_filter_too_short()
+        {
+            const string code = @"
+                namespace Some.Namespace
+                {
+                    public class Options {}
+                }";
+
+            var usages = await FindSymbolsWithFilterAsync(code, "op", 3, 0);
+            var symbols = usages.QuickFixes.Select(q => q.Text);
+
+            Assert.Empty(symbols);
+        }
+
+        [Fact]
+        public async Task limit_number_of_returned_symbols()
+        {
+            const string code = @"
+                namespace Some.Namespace
+                {
+                    public class Options1 {}
+                    public class Options2 {}
+                    public class Options3 {}
+                }";
+
+            var usages = await FindSymbolsWithFilterAsync(code, "op", 0, 2);
+            var symbols = usages.QuickFixes.Select(q => q.Text);
+
+            Assert.Equal(2, symbols.Count());
+        }
 
         private async Task<QuickFixResponse> FindSymbolsAsync(string code)
         {
@@ -263,13 +294,17 @@ private async Task<QuickFixResponse> FindSymbolsAsync(string code)
             return await requestHandler.Handle(null);
         }
 
-        private async Task<QuickFixResponse> FindSymbolsWithFilterAsync(string code, string filter)
+        private async Task<QuickFixResponse> FindSymbolsWithFilterAsync(string code, string filter, int minFilterLength, int maxItemsToReturn)
         {
             var testFile = new TestFile("dummy.cs", code);
             SharedOmniSharpTestHost.AddFilesToWorkspace(testFile);
             var requestHandler = GetRequestHandler(SharedOmniSharpTestHost);
 
-            return await requestHandler.Handle(new FindSymbolsRequest { Filter = filter });
+            return await requestHandler.Handle(new FindSymbolsRequest {
+                Filter = filter,
+                MinFilterLength = minFilterLength,
+                MaxItemsToReturn = maxItemsToReturn
+            });
         }
     }
 }