Expose server build information

Co-authored-by: Professor Bloodstone <git@bloodstone.dev>
Co-authored-by: Mark Vainomaa <mikroskeem@mikroskeem.eu>
Co-authored-by: masmc05 <masmc05@gmail.com>
Co-authored-by: Riley Park <rileysebastianpark@gmail.com>

paper-api/src/main/java/io/papermc/paper/ServerBuildInfo.java

@@ -0,0 +1,122 @@
+package io.papermc.paper;
+
+import java.time.Instant;
+import java.util.Optional;
+import java.util.OptionalInt;
+import net.kyori.adventure.key.Key;
+import net.kyori.adventure.util.Services;
+import org.jetbrains.annotations.ApiStatus;
+import org.jspecify.annotations.NullMarked;
+
+/**
+ * Information about the current server build.
+ */
+@NullMarked
+@ApiStatus.NonExtendable
+public interface ServerBuildInfo {
+    /**
+     * The brand id for Paper.
+     */
+    Key BRAND_PAPER_ID = Key.key("papermc", "paper");
+
+    /**
+     * Gets the {@code ServerBuildInfo}.
+     *
+     * @return the {@code ServerBuildInfo}
+     */
+    static ServerBuildInfo buildInfo() {
+        //<editor-fold defaultstate="collapsed" desc="Holder">
+        final class Holder {
+            static final Optional<ServerBuildInfo> INSTANCE = Services.service(ServerBuildInfo.class);
+        }
+        //</editor-fold>
+        return Holder.INSTANCE.orElseThrow();
+    }
+
+    /**
+     * Gets the brand id of the server.
+     *
+     * @return the brand id of the server (e.g. "papermc:paper")
+     */
+    Key brandId();
+
+    /**
+     * Checks if the current server supports the specified brand.
+     *
+     * @param brandId the brand to check (e.g. "papermc:folia")
+     * @return {@code true} if the server supports the specified brand
+     */
+    @ApiStatus.Experimental
+    boolean isBrandCompatible(final Key brandId);
+
+    /**
+     * Gets the brand name of the server.
+     *
+     * @return the brand name of the server (e.g. "Paper")
+     */
+    String brandName();
+
+    /**
+     * Gets the Minecraft version id.
+     *
+     * @return the Minecraft version id (e.g. "1.20.4", "1.20.2-pre2", "23w31a")
+     */
+    String minecraftVersionId();
+
+    /**
+     * Gets the Minecraft version name.
+     *
+     * @return the Minecraft version name (e.g. "1.20.4", "1.20.2 Pre-release 2", "23w31a")
+     */
+    String minecraftVersionName();
+
+    /**
+     * Gets the build number.
+     *
+     * @return the build number
+     */
+    OptionalInt buildNumber();
+
+    /**
+     * Gets the build time.
+     *
+     * @return the build time
+     */
+    Instant buildTime();
+
+    /**
+     * Gets the git commit branch.
+     *
+     * @return the git commit branch
+     */
+    Optional<String> gitBranch();
+
+    /**
+     * Gets the git commit hash.
+     *
+     * @return the git commit hash
+     */
+    Optional<String> gitCommit();
+
+    /**
+     * Creates a string representation of the server build information.
+     *
+     * @param representation the type of representation
+     * @return a string
+     */
+    String asString(final StringRepresentation representation);
+
+    /**
+     * String representation types.
+     */
+    enum StringRepresentation {
+        /**
+         * A simple version string, in format {@code <minecraftVersionId>-<buildNumber>-<gitCommit>}.
+         */
+        VERSION_SIMPLE,
+        /**
+         * A simple version string, in format {@code <minecraftVersionId>-<buildNumber>-<gitBranch>@<gitCommit> (<buildTime>)}.
+         */
+        VERSION_FULL,
+    }
+}

paper-api/src/main/java/io/papermc/paper/util/JarManifests.java

@@ -0,0 +1,38 @@
+package io.papermc.paper.util;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.net.URL;
+import java.util.Collections;
+import java.util.Map;
+import java.util.WeakHashMap;
+import java.util.jar.Manifest;
+import org.jetbrains.annotations.ApiStatus;
+import org.jspecify.annotations.NullMarked;
+import org.jspecify.annotations.Nullable;
+
+@NullMarked
+@ApiStatus.Internal
+public final class JarManifests {
+    private JarManifests() {
+    }
+
+    private static final Map<ClassLoader, Manifest> MANIFESTS = Collections.synchronizedMap(new WeakHashMap<>());
+
+    public static @Nullable Manifest manifest(final Class<?> clazz) {
+        return MANIFESTS.computeIfAbsent(clazz.getClassLoader(), classLoader -> {
+            final String classLocation = "/" + clazz.getName().replace(".", "/") + ".class";
+            final URL resource = clazz.getResource(classLocation);
+            if (resource == null) {
+                return null;
+            }
+            final String classFilePath = resource.toString().replace("\\", "/");
+            final String archivePath = classFilePath.substring(0, classFilePath.length() - classLocation.length());
+            try (final InputStream stream = new URL(archivePath + "/META-INF/MANIFEST.MF").openStream()) {
+                return new Manifest(stream);
+            } catch (final IOException ex) {
+                return null;
+            }
+        });
+    }
+}