From 9e247bee7b3a4b5109c94570b4bca52d87b35a5c Mon Sep 17 00:00:00 2001
From: Anna <microsoft@annaclemens.io>
Date: Sun, 31 Jan 2021 23:59:04 -0500
Subject: [PATCH] fix: kill old classifiers

---
 NoSoliciting/Ml/MlFilter.cs | 63 ++++++++++++++++++++++++++++++-------
 1 file changed, 51 insertions(+), 12 deletions(-)

diff --git a/NoSoliciting/Ml/MlFilter.cs b/NoSoliciting/Ml/MlFilter.cs
index cc7b5b3..e9fed84 100644
--- a/NoSoliciting/Ml/MlFilter.cs
+++ b/NoSoliciting/Ml/MlFilter.cs
@@ -74,20 +74,22 @@ namespace NoSoliciting.Ml {
             UpdateCachedFile(plugin, ModelName, data);
             UpdateCachedFile(plugin, ManifestName, Encoding.UTF8.GetBytes(manifest.Item2));
 
-            using var exe = Resource.AsStream("NoSoliciting.NoSoliciting.MessageClassifier.exe");
             var pluginFolder = Util.PluginFolder(plugin);
-            Directory.CreateDirectory(pluginFolder);
-            var exePath = Path.Combine(pluginFolder, "NoSoliciting.MessageClassifier.exe");
-            using (var exeFile = File.Create(exePath)) {
-                await exe.CopyToAsync(exeFile);
-            }
 
-            var startInfo = new ProcessStartInfo(exePath) {
-                CreateNoWindow = true,
-                UseShellExecute = false,
-            };
-            var process = Process.Start(startInfo);
+            var pidPath = Path.Combine(pluginFolder, "classifier.pid");
 
+            // close the old classifier if it's still open
+            CloseOldClassifier(pidPath);
+
+            var exePath = await ExtractClassifier(pluginFolder);
+
+            var process = StartClassifier(exePath, pidPath);
+            var client = await CreateClassifierClient(data);
+
+            return new MlFilter(manifest.Item1.Version, process!, client);
+        }
+
+        private static async Task<IIpcClient<IClassifier>> CreateClassifierClient(byte[] data) {
             var serviceProvider = new ServiceCollection()
                 .AddNamedPipeIpcClient<IClassifier>("client", (_, options) => {
                     options.PipeName = "NoSoliciting.MessageClassifier";
@@ -99,8 +101,45 @@ namespace NoSoliciting.Ml {
             var client = clientFactory.CreateClient("client");
 
             await client.InvokeAsync(classifier => classifier.Initialise(data));
+            return client;
+        }
 
-            return new MlFilter(manifest.Item1.Version, process!, client);
+        private static Process StartClassifier(string exePath, string pidPath) {
+            var startInfo = new ProcessStartInfo(exePath) {
+                CreateNoWindow = true,
+                UseShellExecute = false,
+            };
+            var process = Process.Start(startInfo);
+            File.WriteAllText(pidPath, process!.Id.ToString());
+            return process;
+        }
+
+        private static async Task<string> ExtractClassifier(string pluginFolder) {
+            using var exe = Resource.AsStream("NoSoliciting.NoSoliciting.MessageClassifier.exe");
+            Directory.CreateDirectory(pluginFolder);
+            var exePath = Path.Combine(pluginFolder, "NoSoliciting.MessageClassifier.exe");
+            using var exeFile = File.Create(exePath);
+            await exe.CopyToAsync(exeFile);
+
+            return exePath;
+        }
+
+        private static void CloseOldClassifier(string pidPath) {
+            if (!File.Exists(pidPath)) {
+                return;
+            }
+
+            if (!int.TryParse(File.ReadAllText(pidPath).Trim(), out var pid)) {
+                return;
+            }
+
+            try {
+                var old = Process.GetProcessById(pid);
+                old.Kill();
+                old.WaitForExit();
+            } catch (ArgumentException) {
+                // ignore
+            }
         }
 
         private static async Task<byte[]?> DownloadModel(Uri url) {