From 20c7891c2fbc73031f60cf8d58d6fad009f75e2a Mon Sep 17 00:00:00 2001
From: Julian Krings <juliankrings6@gmail.com>
Date: Mon, 7 Jul 2025 22:54:35 +0200
Subject: [PATCH] add api generation task

---
 build.gradle.kts                         |   1 +
 buildSrc/build.gradle.kts                |  11 +++
 buildSrc/src/main/kotlin/ApiGenerator.kt | 101 +++++++++++++++++++++++
 3 files changed, 113 insertions(+)
 create mode 100644 buildSrc/build.gradle.kts
 create mode 100644 buildSrc/src/main/kotlin/ApiGenerator.kt

diff --git a/build.gradle.kts b/build.gradle.kts
index 5681a8cf4..733f6134e 100644
--- a/build.gradle.kts
+++ b/build.gradle.kts
@@ -35,6 +35,7 @@ plugins {
     id("xyz.jpenilla.run-paper") version "2.3.1"
     id("io.sentry.jvm.gradle") version "5.7.0"
 }
+apply<ApiGenerator>()
 
 version = "3.6.11-1.20.1-1.21.5"
 
diff --git a/buildSrc/build.gradle.kts b/buildSrc/build.gradle.kts
new file mode 100644
index 000000000..c94238170
--- /dev/null
+++ b/buildSrc/build.gradle.kts
@@ -0,0 +1,11 @@
+plugins {
+    kotlin("jvm") version "2.0.20"
+}
+
+repositories {
+    mavenCentral()
+}
+
+dependencies {
+    implementation("org.ow2.asm:asm:9.8")
+}
\ No newline at end of file
diff --git a/buildSrc/src/main/kotlin/ApiGenerator.kt b/buildSrc/src/main/kotlin/ApiGenerator.kt
new file mode 100644
index 000000000..f1bd334d5
--- /dev/null
+++ b/buildSrc/src/main/kotlin/ApiGenerator.kt
@@ -0,0 +1,101 @@
+import org.gradle.api.DefaultTask
+import org.gradle.api.Plugin
+import org.gradle.api.Project
+import org.gradle.api.provider.Provider
+import org.gradle.api.tasks.InputFile
+import org.gradle.api.tasks.OutputFile
+import org.gradle.api.tasks.TaskAction
+import org.gradle.jvm.tasks.Jar
+import org.objectweb.asm.*
+import java.io.File
+import java.util.jar.JarFile
+import java.util.jar.JarOutputStream
+
+class ApiGenerator : Plugin<Project> {
+    override fun apply(target: Project) {
+        target.tasks.register("generateApi", GenerateApiTask::class.java)
+    }
+}
+
+abstract class GenerateApiTask : DefaultTask() {
+    init {
+        group = "iris"
+        dependsOn("jar")
+    }
+
+    @InputFile
+    val inputFile: Provider<File> = project.tasks
+        .named("jar", Jar::class.java)
+        .flatMap { it.archiveFile }
+        .map { it.asFile }
+
+    @OutputFile
+    val outputFile: Provider<File> = inputFile.map { targetDirectory().resolve(it.name) }
+
+    @TaskAction
+    fun generate() {
+        JarFile(inputFile.get()).use { jar ->
+            JarOutputStream(outputFile.get().outputStream()).use { out ->
+                jar.stream()
+                    .parallel()
+                    .filter { !it.isDirectory }
+                    .filter { it.name.endsWith(".class") }
+                    .forEach {
+                        val bytes = jar.getInputStream(it).use { input ->
+                            val writer = ClassWriter(ClassWriter.COMPUTE_MAXS)
+                            val visitor = MethodClearingVisitor(writer)
+                            ClassReader(input).accept(visitor, 0)
+                            writer.toByteArray()
+                        }
+
+                        synchronized(out) {
+                            out.putNextEntry(it)
+                            out.write(bytes)
+                            out.closeEntry()
+                        }
+                    }
+            }
+        }
+    }
+
+    fun targetDirectory(): File {
+        val dir = System.getenv("DEPLOY_DIR") ?: return project.layout.buildDirectory.dir("api").get().asFile
+        return File(dir)
+    }
+}
+
+private class MethodClearingVisitor(
+    cv: ClassVisitor
+) : ClassVisitor(Opcodes.ASM9, cv) {
+
+    override fun visitMethod(
+        access: Int,
+        name: String?,
+        descriptor: String?,
+        signature: String?,
+        exceptions: Array<out String>?
+    ) = ExceptionThrowingMethodVisitor(super.visitMethod(access, name, descriptor, signature, exceptions))
+}
+
+private class ExceptionThrowingMethodVisitor(
+    mv: MethodVisitor
+) : MethodVisitor(Opcodes.ASM9, mv) {
+
+    override fun visitCode() {
+        if (mv == null) return
+        mv.visitCode()
+
+        mv.visitTypeInsn(Opcodes.NEW, "java/lang/IllegalStateException")
+        mv.visitInsn(Opcodes.DUP)
+        mv.visitLdcInsn("Only API")
+        mv.visitMethodInsn(
+            Opcodes.INVOKESPECIAL,
+            "java/lang/IllegalStateException",
+            "<init>", "(Ljava/lang/String;)V", false
+        )
+        mv.visitInsn(Opcodes.ATHROW)
+
+        mv.visitMaxs(0, 0)
+        mv.visitEnd()
+    }
+}
\ No newline at end of file