Added support for a global omnisharp.json

src/OmniSharp.Abstractions/Services/IOmniSharpEnvironment.cs

@@ -9,6 +9,7 @@ public interface IOmniSharpEnvironment
         int HostPID { get; }
         string Path { get; }
         string SolutionFilePath { get; }
+        string SharedDirectoryPath { get; }
         TransportType TransportType { get; }
         string[] OtherArgs { get; }
     }

src/OmniSharp.Host/Internal/CommandOptionExtensions.cs

@@ -15,4 +15,4 @@ internal static T GetValueOrDefault<T>(this CommandOption opt, T defaultValue)
             return defaultValue;
         }
     }
-}
+}

src/OmniSharp.Host/Internal/ConfigurationBuilderExtensions.cs

@@ -0,0 +1,36 @@
+using Microsoft.Extensions.Configuration;
+using Microsoft.Extensions.FileProviders;
+using OmniSharp.Services;
+using System;
+using System.IO;
+
+namespace OmniSharp.Host.Internal
+{
+    internal static class ConfigurationBuilderExtensions
+    {
+        internal static void CreateAndAddGlobalOptionsFile(this IConfigurationBuilder configBuilder, IOmniSharpEnvironment env)
+        {
+            if (env?.SharedDirectoryPath == null) return;
+
+            try
+            {
+                if (!Directory.Exists(env.SharedDirectoryPath))
+                {
+                    Directory.CreateDirectory(env.SharedDirectoryPath);
+                }
+
+                var omnisharpGlobalFilePath = Path.Combine(env.SharedDirectoryPath, Constants.OptionsFile);
+                configBuilder.AddJsonFile(
+                    new PhysicalFileProvider(env.SharedDirectoryPath),
+                    Constants.OptionsFile,
+                    optional: true,
+                    reloadOnChange: true);
+            }
+            catch (Exception e)
+            {
+                // at this point we have no ILogger yet
+                Console.Error.WriteLine($"There was an error when trying to create a global '{Constants.OptionsFile}' file in '{env.SharedDirectoryPath}'. {e.ToString()}");
+            }
+        }
+    }
+}

src/OmniSharp.Host/Internal/OmniSharpConstants.cs

@@ -0,0 +1,8 @@
+namespace OmniSharp.Host.Internal
+{
+    internal static class Constants
+    {
+        internal const string ConfigFile = "config.json";
+        internal const string OptionsFile = "omnisharp.json";
+    }
+}

src/OmniSharp.Host/Services/OmniSharpEnvironment.cs

@@ -7,6 +7,7 @@ public class OmniSharpEnvironment : IOmniSharpEnvironment
     {
         public string Path { get; }
         public string SolutionFilePath { get; }
+        public string SharedDirectoryPath { get; }
         public int Port { get; }
         public int HostPID { get; }
         public LogLevel TraceType { get; }
@@ -38,6 +39,16 @@ public OmniSharpEnvironment(
             TraceType = traceType;
             TransportType = transportType;
             OtherArgs = otherArgs;
+
+            // On Windows: %APPDATA%\.omnisharp\omnisharp.json
+            // On Mac/Linux: ~/.omnisharp/omnisharp.json
+            var root = Environment.GetEnvironmentVariable("USERPROFILE") ??
+                Environment.GetEnvironmentVariable("HOME");
+
+            if (root != null)
+            {
+                SharedDirectoryPath = System.IO.Path.Combine(root, ".omnisharp");
+            }
         }
     }
 }

src/OmniSharp.Host/Startup.cs

@@ -12,6 +12,7 @@
 using Microsoft.Extensions.FileProviders;
 using Microsoft.Extensions.Logging;
 using Microsoft.Extensions.Options;
+using OmniSharp.Host.Internal;
 using OmniSharp.Mef;
 using OmniSharp.Middleware;
 using OmniSharp.Options;
@@ -36,18 +37,21 @@ public Startup(IOmniSharpEnvironment env)
 
             var configBuilder = new ConfigurationBuilder()
                 .SetBasePath(AppContext.BaseDirectory)
-                .AddJsonFile("config.json", optional: true)
+                .AddJsonFile(Constants.ConfigFile, optional: true)
                 .AddEnvironmentVariables();
 
             if (env.OtherArgs?.Length > 0)
             {
                 configBuilder.AddCommandLine(env.OtherArgs);
             }
 
+            // Use the global omnisharp config if there's any in the shared path
+            configBuilder.CreateAndAddGlobalOptionsFile(env);
+
             // Use the local omnisharp config if there's any in the root path
             configBuilder.AddJsonFile(
                 new PhysicalFileProvider(env.Path),
-                "omnisharp.json",
+                Constants.OptionsFile,
                 optional: true,
                 reloadOnChange: true);