Easily sync config values between server & client

src/main/java/com/gtnewhorizon/gtnhlib/config/Config.java

@@ -224,4 +224,21 @@
     @Retention(RetentionPolicy.RUNTIME)
     @Target(ElementType.TYPE)
     @interface ExcludeFromAutoGui {}
+
+    /**
+     * Fields or classes annotated with this will automatically be synced from server -> client. If applied to a class,
+     * all fields (including subcategories) in the class will be synced. All fields are restored to their original value
+     * when the player disconnects.
+     */
+    @Retention(RetentionPolicy.RUNTIME)
+    @Target({ ElementType.FIELD, ElementType.TYPE })
+    @interface Sync {
+
+        /**
+         * Can be used to overwrite the sync behavior for fields in classes annotated with {@link Sync}.
+         * 
+         * @return Whether the field should be synced. Defaults to true.
+         */
+        boolean value() default true;
+    }
 }

src/main/java/com/gtnewhorizon/gtnhlib/config/ConfigFieldParser.java

@@ -142,6 +142,39 @@ private static boolean isModDetected(Config.ModDetectedDefault modDefault) {
         });
     }
 
+    static String getValueAsString(@Nullable Object instance, Field field) throws ConfigException {
+        try {
+            val parser = getParser(field);
+            return parser.getAsString(instance, field);
+        } catch (Exception e) {
+            throw new ConfigException(
+                    "Failed to get value as string for field " + field.getName()
+                            + " of type "
+                            + field.getType().getSimpleName()
+                            + " in class "
+                            + field.getDeclaringClass().getName()
+                            + ". Caused by: "
+                            + e);
+        }
+    }
+
+    static void setValueFromString(@Nullable Object instance, Field field, String value) throws ConfigException {
+        try {
+            val parser = getParser(field);
+            parser.setFromString(instance, value, field);
+        } catch (Exception e) {
+            throw new ConfigException(
+                    "Failed to set value from string for field " + field.getName()
+                            + " of type "
+                            + field.getType().getSimpleName()
+                            + " in class "
+                            + field.getDeclaringClass().getName()
+                            + ". Caused by: "
+                            + e);
+        }
+
+    }
+
     @SneakyThrows
     private static Field extractField(Class<?> clazz, String field) {
         return clazz.getDeclaredField(field);
@@ -158,6 +191,10 @@ void load(@Nullable Object instance, @Nullable String defValueString, Field fiel
                 String category, String name, String comment, String langKey);
 
         void save(@Nullable Object instance, Field field, Configuration config, String category, String name);
+
+        void setFromString(@Nullable Object instance, String value, Field field);
+
+        String getAsString(@Nullable Object instance, Field field);
     }
 
     private static class BooleanParser implements Parser {
@@ -194,6 +231,25 @@ private boolean fromStringOrDefault(@Nullable Object instance, @Nullable String
 
             return Boolean.parseBoolean(defValueString);
         }
+
+        @Override
+        @SneakyThrows
+        public void setFromString(@Nullable Object instance, String value, Field field) {
+            val boxed = field.getType().equals(Boolean.class);
+            if (boxed) {
+                field.set(instance, Boolean.parseBoolean(value));
+                return;
+            }
+
+            field.setBoolean(instance, Boolean.parseBoolean(value));
+        }
+
+        @Override
+        @SneakyThrows
+        public String getAsString(@Nullable Object instance, Field field) {
+            val boxed = field.getType().equals(Boolean.class);
+            return Boolean.toString(boxed ? (Boolean) field.get(instance) : field.getBoolean(instance));
+        }
     }
 
     private static class IntParser implements Parser {
@@ -228,6 +284,25 @@ private int fromStringOrDefault(@Nullable Object instance, @Nullable String defV
 
             return Integer.parseInt(defValueString);
         }
+
+        @Override
+        @SneakyThrows
+        public void setFromString(@Nullable Object instance, String value, Field field) {
+            val boxed = field.getType().equals(Integer.class);
+            if (boxed) {
+                field.set(instance, Integer.parseInt(value));
+                return;
+            }
+
+            field.setInt(instance, Integer.parseInt(value));
+        }
+
+        @Override
+        @SneakyThrows
+        public String getAsString(@Nullable Object instance, Field field) {
+            val boxed = field.getType().equals(Integer.class);
+            return Integer.toString(boxed ? (Integer) field.get(instance) : field.getInt(instance));
+        }
     }
 
     private static class FloatParser implements Parser {
@@ -262,6 +337,25 @@ private float fromStringOrDefault(@Nullable Object instance, @Nullable String de
 
             return Float.parseFloat(defValueString);
         }
+
+        @Override
+        @SneakyThrows
+        public void setFromString(@org.jetbrains.annotations.Nullable Object instance, String value, Field field) {
+            val boxed = field.getType().equals(Float.class);
+            if (boxed) {
+                field.set(instance, Float.parseFloat(value));
+                return;
+            }
+
+            field.setFloat(instance, Float.parseFloat(value));
+        }
+
+        @Override
+        @SneakyThrows
+        public String getAsString(@Nullable Object instance, Field field) {
+            val boxed = field.getType().equals(Float.class);
+            return Float.toString(boxed ? (Float) field.get(instance) : field.getFloat(instance));
+        }
     }
 
     private static class DoubleParser implements Parser {
@@ -301,6 +395,25 @@ private double fromStringOrDefault(@Nullable Object instance, @Nullable String d
 
             return Double.parseDouble(defValueString);
         }
+
+        @Override
+        @SneakyThrows
+        public void setFromString(@Nullable Object instance, String value, Field field) {
+            val boxed = field.getType().equals(Double.class);
+            if (boxed) {
+                field.set(instance, Double.parseDouble(value));
+                return;
+            }
+
+            field.setDouble(instance, Double.parseDouble(value));
+        }
+
+        @Override
+        @SneakyThrows
+        public String getAsString(@Nullable Object instance, Field field) {
+            val boxed = field.getType().equals(Double.class);
+            return Double.toString(boxed ? (Double) field.get(instance) : field.getDouble(instance));
+        }
     }
 
     private static class StringParser implements Parser {
@@ -331,6 +444,18 @@ private String fromStringOrDefault(@Nullable Object instance, @Nullable String d
 
             return defValueString;
         }
+
+        @Override
+        @SneakyThrows
+        public void setFromString(@Nullable Object instance, String value, Field field) {
+            field.set(instance, value);
+        }
+
+        @Override
+        @SneakyThrows
+        public String getAsString(@Nullable Object instance, Field field) {
+            return (String) field.get(instance);
+        }
     }
 
     private static class EnumParser implements Parser {
@@ -415,6 +540,22 @@ private Enum<?> fromStringOrDefault(@Nullable Object instance, @Nullable String
             }
             return null;
         }
+
+        @Override
+        @SneakyThrows
+        public void setFromString(@Nullable Object instance, String value, Field field) {
+            Field enumField = field.getType().getDeclaredField(value);
+            if (!enumField.isEnumConstant()) {
+                throw new NoSuchFieldException();
+            }
+            field.set(instance, enumField.get(instance));
+        }
+
+        @Override
+        @SneakyThrows
+        public String getAsString(@org.jetbrains.annotations.Nullable Object instance, Field field) {
+            return ((Enum<?>) field.get(instance)).name();
+        }
     }
 
     private static class StringArrayParser implements Parser {
@@ -446,6 +587,18 @@ private String[] fromStringOrDefault(@Nullable Object instance, @Nullable String
             }
             return value == null ? new String[0] : value;
         }
+
+        @Override
+        @SneakyThrows
+        public void setFromString(@Nullable Object instance, String value, Field field) {
+            field.set(instance, value.split("|||"));
+        }
+
+        @Override
+        @SneakyThrows
+        public String getAsString(@Nullable Object instance, Field field) {
+            return String.join("|||", (String[]) field.get(instance));
+        }
     }
 
     private static class DoubleArrayParser implements Parser {
@@ -486,6 +639,19 @@ private double[] fromStringOrDefault(@Nullable Object instance, @Nullable String
 
             return value == null ? new double[0] : value;
         }
+
+        @Override
+        @SneakyThrows
+        public void setFromString(@Nullable Object instance, String value, Field field) {
+            field.set(instance, Arrays.stream(value.split(",")).mapToDouble(Double::parseDouble).toArray());
+        }
+
+        @Override
+        @SneakyThrows
+        public String getAsString(@Nullable Object instance, Field field) {
+            return Arrays.stream((double[]) field.get(instance)).mapToObj(Double::toString)
+                    .collect(Collectors.joining(","));
+        }
     }
 
     private static class IntArrayParser implements Parser {
@@ -524,5 +690,18 @@ private int[] fromStringOrDefault(@Nullable Object instance, @Nullable String de
 
             return value == null ? new int[0] : value;
         }
+
+        @Override
+        @SneakyThrows
+        public void setFromString(@Nullable Object instance, String value, Field field) {
+            field.set(instance, Arrays.stream(value.split(",")).mapToInt(Integer::parseInt).toArray());
+        }
+
+        @Override
+        @SneakyThrows
+        public String getAsString(@Nullable Object instance, Field field) {
+            return Arrays.stream((int[]) field.get(instance)).mapToObj(Integer::toString)
+                    .collect(Collectors.joining(","));
+        }
     }
 }

src/main/java/com/gtnewhorizon/gtnhlib/config/ConfigSyncHandler.java

@@ -0,0 +1,67 @@
+package com.gtnewhorizon.gtnhlib.config;
+
+import static com.gtnewhorizon.gtnhlib.config.ConfigurationManager.LOGGER;
+
+import java.util.Map;
+
+import net.minecraft.entity.player.EntityPlayerMP;
+import net.minecraft.server.MinecraftServer;
+import net.minecraft.server.integrated.IntegratedServer;
+
+import com.gtnewhorizon.gtnhlib.network.NetworkHandler;
+
+import cpw.mods.fml.common.FMLCommonHandler;
+import cpw.mods.fml.common.eventhandler.SubscribeEvent;
+import cpw.mods.fml.common.gameevent.PlayerEvent;
+import cpw.mods.fml.common.network.FMLNetworkEvent;
+import it.unimi.dsi.fastutil.objects.Object2ObjectMap;
+import it.unimi.dsi.fastutil.objects.Object2ObjectOpenHashMap;
+
+@SuppressWarnings("unused")
+public final class ConfigSyncHandler {
+
+    static final Map<String, SyncedConfigElement> syncedElements = new Object2ObjectOpenHashMap<>();
+    private static boolean hasSyncedValues = false;
+
+    static {
+        FMLCommonHandler.instance().bus().register(new ConfigSyncHandler());
+    }
+
+    @SubscribeEvent
+    public void onPlayerLogin(PlayerEvent.PlayerLoggedInEvent event) {
+        if (!(event.player instanceof EntityPlayerMP playerMP)) return;
+        MinecraftServer server = MinecraftServer.getServer();
+        // no point in syncing in from client -> client.
+        if (server.isSinglePlayer() && !((IntegratedServer) server).getPublic()) {
+            return;
+        }
+        NetworkHandler.instance.sendTo(new PacketSyncConfig(syncedElements.values()), playerMP);
+    }
+
+    @SubscribeEvent
+    public void onClientDisconnect(FMLNetworkEvent.ClientDisconnectionFromServerEvent event) {
+        if (!hasSyncedValues) return;
+        hasSyncedValues = false;
+        for (SyncedConfigElement element : syncedElements.values()) {
+            element.restoreValue();
+        }
+    }
+
+    static void onSync(PacketSyncConfig packet) {
+        for (Object2ObjectMap.Entry<String, String> entry : packet.syncedElements.object2ObjectEntrySet()) {
+            SyncedConfigElement element = syncedElements.get(entry.getKey());
+            if (element != null) {
+                try {
+                    hasSyncedValues = true;
+                    element.setSyncValue(entry.getValue());
+                } catch (ConfigException e) {
+                    LOGGER.error("Failed to sync element {}", element, e);
+                }
+            }
+        }
+    }
+
+    static boolean hasSyncedValues() {
+        return hasSyncedValues;
+    }
+}