add safety measures

bukkit/src/main/java/revxrsal/commands/bukkit/brigadier/BukkitVersion.java

@@ -0,0 +1,170 @@
+package revxrsal.commands.bukkit.brigadier;
+
+import lombok.SneakyThrows;
+import org.bukkit.Bukkit;
+import org.bukkit.Server;
+import org.jetbrains.annotations.NotNull;
+
+import java.util.regex.Pattern;
+
+/**
+ * A utility for providing information about the server implementation
+ * and version
+ */
+final class BukkitVersion {
+
+    private static final boolean IS_PAPER;
+
+    private static final int MAJOR_VERSION, MINOR_VERSION, PATCH_NUMBER;
+
+    /**
+     * The current version string, for example 1_17_R1
+     */
+    private static final String VERSION = fetchVersion();
+
+    /**
+     * The version where NMS no longer uses versions in the package names
+     */
+    private static final int UNVERSION_NMS = 17;
+
+    /**
+     * The CraftBukkit package
+     */
+    private static final String CB_PACKAGE = Bukkit.getServer().getClass().getPackage().getName();
+
+    static {
+        Pattern dot = Pattern.compile(".", Pattern.LITERAL);
+        String[] version;
+        String bukkitVersion = Bukkit.getServer().getBukkitVersion();
+        if (bukkitVersion.indexOf('-') == -1)
+            version = dot.split(bukkitVersion);
+        else
+            version = dot.split(bukkitVersion.substring(0, bukkitVersion.indexOf('-')));
+
+        if (version.length == 2)
+            version = new String[]{version[0], version[1], "0"};
+        MAJOR_VERSION = Integer.parseInt(version[0]);
+        MINOR_VERSION = Integer.parseInt(version[1]);
+        String minorSlice = version[2];
+        if (minorSlice.indexOf('-') != -1)
+            minorSlice = minorSlice.substring(0, minorSlice.indexOf('-'));
+        PATCH_NUMBER = Integer.parseInt(minorSlice);
+
+        IS_PAPER = isClassPresent("com.destroystokyo.paper.PaperConfig");
+    }
+
+    private BukkitVersion() {
+    }
+
+    /**
+     * Returns the version of the server, e.g. v1_16_R2
+     *
+     * @return The server version
+     */
+    private static @NotNull String fetchVersion() {
+        Server server = Bukkit.getServer();
+        try {
+            String packageName = server.getClass().getPackage().getName();
+            return packageName.substring(packageName.lastIndexOf('.') + 1);
+        } catch (Throwable throwable) {
+            return "";
+        }
+    }
+
+    /**
+     * Tests whether is the given version supported by this server
+     */
+    public static boolean supports(int major, int minor) {
+        return supports(major, minor, 0);
+    }
+
+    /**
+     * Tests whether is the given version supported by this server
+     */
+    public static boolean supports(int major, int minor, int patch) {
+        if (MAJOR_VERSION > major) {
+            return true;
+        } else if (MAJOR_VERSION == major) {
+            if (MINOR_VERSION > minor) {
+                return true;
+            } else if (MINOR_VERSION == minor) {
+                return PATCH_NUMBER >= patch;
+            }
+        }
+        return false;
+    }
+
+    /**
+     * Returns the major version for the current server. For example,
+     * in 1.11.2 this would be 11.
+     *
+     * @return The current version.
+     */
+    public static int minorVersion() {
+        return MINOR_VERSION;
+    }
+
+    /**
+     * Returns the patch number for the current server. For example,
+     * in 1.11.2 this would be 2.
+     *
+     * @return The current version.
+     */
+    public static int patchNumber() {
+        return PATCH_NUMBER;
+    }
+
+    /**
+     * Returns the NMS class with the given name. The name must not contain
+     * the net.minecraft.server prefix.
+     */
+    @SneakyThrows
+    public static @NotNull Class<?> findNmsClass(@NotNull String name) {
+        if (supports(1, UNVERSION_NMS)) {
+            return Class.forName("net.minecraft.server." + name);
+        }
+        return Class.forName("net.minecraft.server." + VERSION + "." + name);
+    }
+
+    /**
+     * Finds and returns the specified class from the CraftBukkit implementation.
+     *
+     * @param name The name of the class to find.
+     * @return The found class.
+     * @throws ClassNotFoundException If the class cannot be found.
+     */
+    @SneakyThrows
+    public static @NotNull Class<?> findOcbClass(@NotNull String name) {
+        return Class.forName(CB_PACKAGE + '.' + name);
+    }
+
+    /**
+     * Tests whether this version is running PaperSpigot
+     *
+     * @return If this is PaperSpigot
+     */
+    public static boolean isPaper() {
+        return IS_PAPER;
+    }
+
+    /**
+     * Tests whether is brigadier supported or not
+     *
+     * @return if brigadier is supported or not
+     */
+    public static boolean isBrigadierSupported() {
+        if (supports(1, 19, 1))
+            return isPaper();
+        else
+            return supports(1, 13);
+    }
+
+    private static boolean isClassPresent(String name) {
+        try {
+            Class.forName(name);
+            return true;
+        } catch (ClassNotFoundException e) {
+            return false;
+        }
+    }
+}

bukkit/src/main/java/revxrsal/commands/bukkit/brigadier/CommodoreProvider.java

@@ -30,6 +30,8 @@
 import java.util.Objects;
 import java.util.function.Function;
 
+import static revxrsal.commands.bukkit.brigadier.BukkitVersion.*;
+
 /**
  * Factory for obtaining instances of {@link Commodore}.
  */
@@ -43,44 +45,19 @@ private CommodoreProvider() {
 
     @SuppressWarnings("Convert2MethodRef")
     private static Function<BukkitCommandHandler, Commodore> checkSupported() {
-        try {
-            Class.forName("com.mojang.brigadier.CommandDispatcher");
-        } catch (Throwable e) {
-            printDebugInfo(e);
+        if (!isBrigadierSupported()) {
             return null;
         }
 
-        // try the reflection impl
-        try {
-            ReflectionCommodore.ensureSetup();
-            return plugin -> new ReflectionCommodore(plugin);
-        } catch (Throwable e) {
-            printDebugInfo(e);
-        }
-
-        try {
-            PaperLifecycleEvents.ensureSetup();
-            return plugin -> new PaperLifecycleEvents(plugin);
-        } catch (Throwable e) {
-            printDebugInfo(e);
-        }
-
-        // try the paper impl
-        try {
-            PaperCommodore.ensureSetup();
-            return plugin -> new PaperCommodore(plugin);
-        } catch (Throwable e) {
-            printDebugInfo(e);
-        }
-
-        return null;
-    }
-
-    private static void printDebugInfo(Throwable e) {
-        if (System.getProperty("commodore.debug") != null) {
-            System.err.println("Exception while initialising commodore:");
-            e.printStackTrace(System.err);
+        if (isPaper()) {
+            if (supports(1, 20, 6)) {
+                return plugin -> new PaperLifecycleEvents(plugin);
+            }
+            if (supports(1, 19)) {
+                return plugin -> new PaperCommodore(plugin);
+            }
         }
+        return plugin -> new ReflectionCommodore(plugin);
     }
 
     /**