From d80825733465db5ae45339c841041682e864cda3 Mon Sep 17 00:00:00 2001
From: Keuin <keuinx@gmail.com>
Date: Sat, 12 Mar 2022 21:50:58 +0800
Subject: Fix config reloading.

---
 .../crosslink/config/GlobalConfigManager.java      | 36 ++++++++++++++++------
 .../keuin/crosslink/plugin/common/PluginMain.java  |  6 ++--
 2 files changed, 29 insertions(+), 13 deletions(-)

diff --git a/src/main/java/com/keuin/crosslink/config/GlobalConfigManager.java b/src/main/java/com/keuin/crosslink/config/GlobalConfigManager.java
index fcc0321..a09fc05 100644
--- a/src/main/java/com/keuin/crosslink/config/GlobalConfigManager.java
+++ b/src/main/java/com/keuin/crosslink/config/GlobalConfigManager.java
@@ -20,8 +20,11 @@ public class GlobalConfigManager {
     private JsonNode configMessaging; // mutable root node of file "messaging.json"
     private JsonNode configApi; // mutable root node of file "api.json"
 
-    private GlobalConfigManager() {
+    private final File configFileDirectory;
+
+    private GlobalConfigManager(File configFileDirectory) {
         mapper.configure(JsonParser.Feature.ALLOW_COMMENTS, true);
+        this.configFileDirectory = configFileDirectory;
     }
 
     /**
@@ -30,24 +33,37 @@ public class GlobalConfigManager {
      *
      * @throws ConfigLoadException failed to load. The 'loaded' status will be set to false.
      */
-    public static void initializeGlobalManager(@NotNull File configFile) throws ConfigLoadException, IOException {
-        Objects.requireNonNull(configFile);
+    public static void initializeGlobalManager(@NotNull File configFileDirectory) throws ConfigLoadException, IOException {
+        Objects.requireNonNull(configFileDirectory);
         synchronized (lock) {
             if (instance == null) {
                 throw new IllegalStateException("already initialized");
             }
-            instance = new GlobalConfigManager();
+            instance = new GlobalConfigManager(configFileDirectory);
         }
-        instance.loadConfig(configFile);
+        instance.loadConfig();
     }
 
-    private void loadConfig(File configDirectory) throws IOException {
-        try (var fis = new FileInputStream(new File(configDirectory, "messaging.json"))) {
-            configMessaging = Optional.ofNullable(mapper.readTree(fis)).orElse(mapper.readTree("{}"));
+    public static void destroyGlobalInstance() {
+        synchronized (lock) {
+            instance = null;
+        }
+    }
+
+    /**
+     * Load config from file.
+     */
+    public void loadConfig() throws IOException {
+        JsonNode newConfigMessaging, newConfigApi;
+        try (var fis = new FileInputStream(new File(configFileDirectory, "messaging.json"))) {
+            newConfigMessaging = Optional.ofNullable(mapper.readTree(fis)).orElse(mapper.readTree("{}"));
         }
-        try (var fis = new FileInputStream(new File(configDirectory, "api.json"))) {
-            configApi = Optional.ofNullable(mapper.readTree(fis)).orElse(mapper.readTree("{}"));
+        try (var fis = new FileInputStream(new File(configFileDirectory, "api.json"))) {
+            newConfigApi = Optional.ofNullable(mapper.readTree(fis)).orElse(mapper.readTree("{}"));
         }
+        // make those two updates atomic (if any exception appeared)
+        configMessaging = newConfigMessaging;
+        configApi = newConfigApi;
     }
 
     public static @NotNull GlobalConfigManager getInstance() {
diff --git a/src/main/java/com/keuin/crosslink/plugin/common/PluginMain.java b/src/main/java/com/keuin/crosslink/plugin/common/PluginMain.java
index aa97a0d..9b0d012 100644
--- a/src/main/java/com/keuin/crosslink/plugin/common/PluginMain.java
+++ b/src/main/java/com/keuin/crosslink/plugin/common/PluginMain.java
@@ -134,8 +134,7 @@ public final class PluginMain {
         // TODO refactor setup and teardown routine, split into hooks
         logger.info("Loading config from disk...");
         try {
-            GlobalConfigManager.initializeGlobalManager(new File(
-                    environment.pluginDataPath().toFile(), "messaging.json"));
+            GlobalConfigManager.initializeGlobalManager(environment.pluginDataPath().toFile());
         } catch (ConfigLoadException | IOException ex) {
             logger.error("Failed to load configuration", ex);
             throw new RuntimeException(ex);
@@ -149,12 +148,13 @@ public final class PluginMain {
         logger.info("Stopping API server.");
         apiServer.shutdown();
         logger.info("CrossLink is disabled.");
+        GlobalConfigManager.destroyGlobalInstance();
     }
 
     // may throw unchecked exception
     public void reload() {
         disable();
-        initialize();
+        enable();
     }
 
     private String capital(String s) {
-- 
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