feat: initial commit, limited implementation of the annotation processor

6 files changed, 224 insertions, 0 deletions

diff --git a/src/main/java/ftbsc/lll/processor/LilleroProcessor.java b/src/main/java/ftbsc/lll/processor/LilleroProcessor.java
new file mode 100644
index 0000000..851987f
--- /dev/null
+++ b/src/main/java/ftbsc/lll/processor/LilleroProcessor.java
@@ -0,0 +1,180 @@
+package ftbsc.lll.processor;
+
+import com.squareup.javapoet.*;
+import ftbsc.lll.IInjector;
+import ftbsc.lll.processor.annotations.Injector;
+import ftbsc.lll.processor.annotations.Patch;
+import ftbsc.lll.tools.DescriptorBuilder;
+import org.objectweb.asm.tree.ClassNode;
+import org.objectweb.asm.tree.MethodNode;
+
+import javax.annotation.processing.*;
+import javax.lang.model.SourceVersion;
+import javax.lang.model.element.ExecutableElement;
+import javax.lang.model.element.Modifier;
+import javax.lang.model.element.TypeElement;
+import javax.lang.model.type.ExecutableType;
+import javax.lang.model.type.TypeMirror;
+import javax.lang.model.util.Elements;
+import javax.lang.model.util.Types;
+import javax.tools.Diagnostic;
+import javax.tools.JavaFileObject;
+import java.io.IOException;
+import java.io.PrintWriter;
+import java.lang.annotation.Annotation;
+import java.lang.annotation.Target;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Set;
+
+@SupportedAnnotationTypes("ftbsc.lll.processor.annotations.Patch")
+@SupportedSourceVersion(SourceVersion.RELEASE_8)
+public class LilleroProcessor extends AbstractProcessor {
+
+	Types types = processingEnv.getTypeUtils();
+	Elements elements = processingEnv.getElementUtils();
+
+	@Override
+	public boolean process(Set<? extends TypeElement> annotations, RoundEnvironment roundEnv) {
+		Set<TypeElement> validInjectors = new HashSet<>();
+		for (TypeElement annotation : annotations) {
+			if(isValidInjector(annotation))
+				validInjectors.add(annotation);
+			else processingEnv.getMessager().printMessage(
+				Diagnostic.Kind.WARNING,
+				"Missing valid inject() method on @Injector class " + annotation.getQualifiedName() + "."
+			);
+		}
+
+		if(validInjectors.isEmpty())
+			return false;
+
+		validInjectors.forEach(this::generateInjector);
+		generateServiceProvider(validInjectors);
+		return true;
+	}
+
+	/** TODO: fancy class object ref in javadoc
+	 * This checks whether a given class contains the requirements to be parsed into a Lillero injector.
+	 * It must have at least one method annotated with @Target, and one method annotated with @Injector
+	 * that must be public, static and take in a ClassNode and a MethodNode.
+	 * @param elem the element to check.
+	 * @return whether it can be converted into a valid IInjector.
+	 */
+	private boolean isValidInjector(TypeElement elem) {
+		TypeMirror classNodeType = processingEnv.getElementUtils().getTypeElement("org.objectweb.asm.tree.ClassNode").asType();
+		TypeMirror methodNodeType = processingEnv.getElementUtils().getTypeElement("org.objectweb.asm.tree.MethodNode").asType();
+		return elem.getEnclosedElements().stream().anyMatch(e -> e.getAnnotation(Target.class) != null)
+			&& elem.getEnclosedElements().stream().anyMatch(e -> {
+			List<? extends TypeMirror> params = ((ExecutableType) e.asType()).getParameterTypes();
+			return e.getAnnotation(Injector.class) != null
+				&& e.getModifiers().contains(Modifier.PUBLIC)
+				&& e.getModifiers().contains(Modifier.STATIC)
+				&& params.size() == 2
+				&& processingEnv.getTypeUtils().isSameType(params.get(0), classNodeType)
+				&& processingEnv.getTypeUtils().isSameType(params.get(1), methodNodeType);
+		});
+	}
+
+	private MethodSpec findAnnotatedMethod(TypeElement cl, Class<? extends Annotation> ann) {
+		return MethodSpec.overriding(
+			(ExecutableElement) cl.getEnclosedElements()
+				.stream()
+				.filter(e -> e.getAnnotation(ann) != null)
+				.findFirst()
+				.get() //will never be null so can ignore warning
+		).build();
+	}
+
+	private String getClassOrString(TypeName n) { //jank but fuck you
+		return n.isPrimitive() ? n + ".class" : "\"" + n + "\"";
+	}
+
+	private String generateDescriptorBuilderString(MethodSpec m) {
+		StringBuilder sb = new StringBuilder();
+		sb.append("new $T().setReturnType(");
+		sb.append(getClassOrString(m.returnType)).append(")");
+		m.parameters.forEach(p -> sb.append(".addParameter(").append(getClassOrString(p.type)).append(")"));
+		sb.append(".build();");
+		return sb.toString();
+	}
+
+	private String getSrgName(MethodSpec m) {
+		return m.name; //TODO;
+	}
+
+	private void generateInjector(TypeElement cl) {
+		Patch ann = cl.getAnnotation(Patch.class);
+		MethodSpec targetMethod = findAnnotatedMethod(cl, Target.class);
+		MethodSpec injectorMethod = findAnnotatedMethod(cl, Injector.class);
+
+		String packageName = cl.getQualifiedName().toString().replace("." + cl.getSimpleName().toString(), "");
+
+		String className = cl.getQualifiedName().toString();
+		String simpleClassName = cl.getSimpleName().toString();
+
+		String injectorClassName = className + "Injector";
+		String injectorSimpleClassName = simpleClassName + "Injector";
+
+		MethodSpec name = MethodSpec.methodBuilder("name")
+			.addModifiers(Modifier.PUBLIC)
+			.returns(String.class)
+			.addStatement("return $S", simpleClassName)
+			.build();
+
+		MethodSpec reason = MethodSpec.methodBuilder("reason")
+			.addModifiers(Modifier.PUBLIC)
+			.returns(String.class)
+			.addStatement("return $S", ann.reason())
+			.build();
+
+		MethodSpec targetClass = MethodSpec.methodBuilder("targetClass")
+			.addModifiers(Modifier.PUBLIC)
+			.returns(String.class)
+			.addStatement("return $S", ann.value().getName())
+			.build();
+
+		MethodSpec methodName = MethodSpec.methodBuilder("methodName")
+			.addModifiers(Modifier.PUBLIC)
+			.returns(String.class)
+			.addStatement("return $S", getSrgName(targetMethod))
+			.build();
+
+		MethodSpec methodDesc = MethodSpec.methodBuilder("methodDesc")
+			.addModifiers(Modifier.PUBLIC)
+			.returns(String.class)
+			.addCode(generateDescriptorBuilderString(targetMethod), DescriptorBuilder.class)
+			.build();
+
+		MethodSpec inject = MethodSpec.methodBuilder("inject")
+			.addModifiers(Modifier.PUBLIC)
+			.returns(void.class)
+			.addParameter(ParameterSpec.builder(ClassNode.class, "clazz").build())
+			.addParameter(ParameterSpec.builder(MethodNode.class, "main").build())
+			.addStatement("$S.$S(clazz, main)", className, injectorMethod.name)
+			.build();
+
+		TypeSpec injectorClass = TypeSpec.classBuilder(injectorSimpleClassName)
+			.addModifiers(Modifier.PUBLIC)
+			.addSuperinterface(ClassName.get(IInjector.class))
+			.addMethod(name)
+			.addMethod(reason)
+			.addMethod(targetClass)
+			.addMethod(methodName)
+			.addMethod(methodDesc)
+			.addMethod(inject)
+			.build();
+
+		try {
+			JavaFileObject builderFile = processingEnv.getFiler().createSourceFile(injectorClassName);
+			PrintWriter out = new PrintWriter(builderFile.openWriter());
+
+			JavaFile javaFile = JavaFile.builder(packageName, injectorClass).build();
+			javaFile.writeTo(out);
+		} catch(IOException e) {}
+	}
+
+	private void generateServiceProvider(Set<TypeElement> inj) {
+		//todo generate the services file
+	}
+}
\ No newline at end of file
diff --git a/src/main/java/ftbsc/lll/processor/Main.java b/src/main/java/ftbsc/lll/processor/Main.java
new file mode 100644
index 0000000..54de47b
--- /dev/null
+++ b/src/main/java/ftbsc/lll/processor/Main.java
@@ -0,0 +1,11 @@
+package ftbsc.lll.processor;
+
+import org.gradle.api.Plugin;
+import org.gradle.api.Project;
+
+public class Main implements Plugin<Project> {
+	@Override
+	public void apply(Project project) {
+
+	}
+}
diff --git a/src/main/java/ftbsc/lll/processor/annotations/Injector.java b/src/main/java/ftbsc/lll/processor/annotations/Injector.java
new file mode 100644
index 0000000..6184610
--- /dev/null
+++ b/src/main/java/ftbsc/lll/processor/annotations/Injector.java
@@ -0,0 +1,10 @@
+package ftbsc.lll.processor.annotations;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+@Retention(RetentionPolicy.SOURCE)
+@Target(ElementType.METHOD)
+public @interface Injector {}
diff --git a/src/main/java/ftbsc/lll/processor/annotations/Patch.java b/src/main/java/ftbsc/lll/processor/annotations/Patch.java
new file mode 100644
index 0000000..adbb674
--- /dev/null
+++ b/src/main/java/ftbsc/lll/processor/annotations/Patch.java
@@ -0,0 +1,13 @@
+package ftbsc.lll.processor.annotations;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+@Retention(RetentionPolicy.SOURCE)
+@Target(ElementType.TYPE)
+public @interface Patch {
+	Class<?> value();
+	String reason() default "No reason specified.";
+}
diff --git a/src/main/java/ftbsc/lll/processor/annotations/Target.java b/src/main/java/ftbsc/lll/processor/annotations/Target.java
new file mode 100644
index 0000000..e408755
--- /dev/null
+++ b/src/main/java/ftbsc/lll/processor/annotations/Target.java
@@ -0,0 +1,9 @@
+package ftbsc.lll.processor.annotations;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+
+@Retention(RetentionPolicy.SOURCE)
+@java.lang.annotation.Target(ElementType.METHOD)
+public @interface Target {}
diff --git a/src/main/resources/META-INF/services/javax.annotation.processing.Processor b/src/main/resources/META-INF/services/javax.annotation.processing.Processor
new file mode 100644
index 0000000..508214e
--- /dev/null
+++ b/src/main/resources/META-INF/services/javax.annotation.processing.Processor
@@ -0,0 +1 @@
+ftbsc.lll.processor.LilleroProcessor
\ No newline at end of file