fix EarlyConfig NPE from race conditions

src/main/java/com/falsepattern/lib/internal/config/EarlyConfig.java

@@ -24,14 +24,21 @@
 package com.falsepattern.lib.internal.config;
 
 import com.falsepattern.lib.StableAPI;
+import com.falsepattern.lib.internal.FalsePatternLib;
+import com.falsepattern.lib.internal.Tags;
 import com.falsepattern.lib.internal.core.LowLevelCallMultiplexer;
 import com.google.gson.Gson;
+import com.google.gson.GsonBuilder;
 import com.google.gson.annotations.Expose;
 import lombok.Data;
 import lombok.SneakyThrows;
 import lombok.experimental.Accessors;
 import lombok.val;
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.jetbrains.annotations.NotNull;
 
+import java.io.IOException;
 import java.nio.charset.StandardCharsets;
 import java.nio.file.Files;
 
@@ -43,22 +50,45 @@ public class EarlyConfig {
  @StableAPI.Expose(since = "__INTERNAL__")
  private boolean enableLibraryDownloads;
 
- private static EarlyConfig instance = null;
+ private static volatile EarlyConfig instance = null;
 
- @SneakyThrows
- public static EarlyConfig load() {
- if (instance != null)
- return instance;
- val configFile = LowLevelCallMultiplexer.gameDir().resolve("config").resolve("falsepatternlib-early.json");
- val gson = new Gson();
- EarlyConfig config;
- if (!Files.exists(configFile)) {
+ private static final Logger LOG = LogManager.getLogger(Tags.MODNAME + " Early Config");
+
+ public static @NotNull EarlyConfig getInstance() {
+ val config = instance;
+ if (config != null)
+ return config;
+ return loadFromDisk();
+ }
+
+ private static synchronized @NotNull EarlyConfig loadFromDisk() {
+ var config = instance;
+ if (config != null) {
+ return config;
+ }
+ val configDir = LowLevelCallMultiplexer.gameDir().resolve("config");
+ val configFile = configDir.resolve("falsepatternlib-early.json");
+ val gson = new GsonBuilder().setPrettyPrinting().create();
+ try {
+ if (!Files.exists(configDir)) {
+ Files.createDirectories(configDir);
+ }
+ if (Files.exists(configFile)) {
+ config = gson.fromJson(new String(Files.readAllBytes(configFile), StandardCharsets.UTF_8),
+ EarlyConfig.class);
+ }
+ } catch (IOException e) {
+ LOG.error("Failed to load from disk", e);
+ }
+ if (config == null) {
  config = new EarlyConfig();
  config.enableLibraryDownloads(true);
- } else {
- config = gson.fromJson(new String(Files.readAllBytes(configFile), StandardCharsets.UTF_8), EarlyConfig.class);
+ try {
+ Files.write(configFile, gson.toJson(config).getBytes(StandardCharsets.UTF_8));
+ } catch (IOException e) {
+ LOG.error("Failed to write to disk", e);
+ }
  }
- Files.write(configFile, gson.toJson(config).getBytes(StandardCharsets.UTF_8));
  instance = config;
  return config;
  }

src/main/java/com/falsepattern/lib/internal/core/LowLevelCallMultiplexer.java

@@ -25,6 +25,7 @@
 
 import com.gtnewhorizons.retrofuturabootstrap.RfbApiImpl;
 import lombok.experimental.UtilityClass;
+import org.jetbrains.annotations.NotNull;
 
 import net.minecraft.launchwrapper.Launch;
 
@@ -56,7 +57,7 @@ public static List<URL> getClassPathSources() {
  }
  }
 
- public static Path gameDir() {
+ public static @NotNull Path gameDir() {
  if (rfbDetected) {
  return RFBLowLevel.gameDir();
  } else {
@@ -76,7 +77,7 @@ static List<URL> getClassPathSources() {
  return RfbApiImpl.INSTANCE.compatClassLoader().getSources();
  }
 
- static Path gameDir() {
+ static @NotNull Path gameDir() {
  return RfbApiImpl.INSTANCE.gameDirectory();
  }
  }
@@ -90,7 +91,7 @@ static List<URL> getClassPathSources() {
  return Launch.classLoader.getSources();
  }
 
- static Path gameDir() {
+ static @NotNull Path gameDir() {
  return Launch.minecraftHome == null ? Paths.get(".") : Launch.minecraftHome.toPath();
  }
  }

src/main/java/com/falsepattern/lib/internal/impl/dependencies/DependencyLoaderImpl.java

@@ -805,7 +805,7 @@ private boolean tryLoadingExistingFile() {
  }
 
  private void validateDownloadsAllowed() {
- if (!EarlyConfig.load().enableLibraryDownloads()) {
+ if (!EarlyConfig.getInstance().enableLibraryDownloads()) {
  val errorMessage = "Failed to load library "
  + groupId
  + ":"