feat: added ClassProxy

1 files changed, 174 insertions, 0 deletions

diff --git a/src/main/java/ftbsc/lll/proxies/ClassProxy.java b/src/main/java/ftbsc/lll/proxies/ClassProxy.java
new file mode 100644
index 0000000..c369231
--- /dev/null
+++ b/src/main/java/ftbsc/lll/proxies/ClassProxy.java
@@ -0,0 +1,174 @@
+package ftbsc.lll.proxies;
+
+import org.objectweb.asm.Type;
+
+/**
+ * A container for information about classes to be used
+ * in ASM patching.
+ * @since 0.4.0
+ */
+public class ClassProxy extends AbstractProxy {
+
+	/**
+	 * The fully-qualified name of the class represented by this proxy.
+	 */
+	public final String fqn;
+
+	/**
+	 * The {@link ClassProxy} representing the class which contains the
+	 * class represented by this proxy. May be null if the class represented
+	 * by this proxy is not an inner class.
+	 */
+	public final ClassProxy containerClass;
+
+	/**
+	 * Protected constructor, called only from the builder.
+	 * @param name the name of the class
+	 * @param type the {@link Type} of the class
+	 * @param modifiers the modifiers of the class
+	 * @param parent the FQN of the parent class of the class
+	 */
+	protected ClassProxy(String name, Type type, int modifiers, String parent) {
+		super(name, type, modifiers, parent);
+		this.fqn = String.format("%s.%s", name, parent);
+		this.containerClass = null;
+	}
+
+	/**
+	 * Protected constructor, called only from the builder.
+	 * @param name the name of the class
+	 * @param type the {@link Type} of the class
+	 * @param modifiers the modifiers of the class
+	 * @param containerClass the FQN of the parent class of the class
+	 */
+	protected ClassProxy(String name, Type type, int modifiers, ClassProxy containerClass) {
+		super(name, type, modifiers, containerClass.fqn);
+		this.fqn = String.format("%s$%s", name, parent);
+		this.containerClass = containerClass;
+	}
+
+	/**
+	 * Builds a {@link ClassProxy} given only the fully-qualified name and modifiers.
+	 * @param fqn the fully qualified name of the desired class
+	 * @param modifiers the access modifiers of the desired class
+	 * @return the built {@link ClassProxy}
+	 */
+	protected static ClassProxy from(String fqn, int modifiers) {
+		Type type = Type.getObjectType(fqn.replace('.', '/'));
+		if(fqn.contains("$")) {
+			String[] split = fqn.split("\\$");
+			String simpleName = split[split.length - 1];
+			ClassProxy parentClass = from(fqn.replace("$" + simpleName, ""), 0);
+			return new ClassProxy(simpleName, type, modifiers, parentClass);
+		} else {
+			String[] split = fqn.split("\\.");
+			String simpleName = split[split.length - 1];
+			String parent = fqn.replace("." + simpleName, "");
+			return new ClassProxy(simpleName, type, modifiers, parent);
+		}
+	}
+
+	/**
+	 * Builds a {@link ClassProxy} from a {@link Class} object.
+	 * @param clazz the {@link Class} object representing the target class
+	 * @return the built {@link ClassProxy}
+	 */
+	protected static ClassProxy from(Class<?> clazz) {
+		if(clazz.getEnclosingClass() == null)
+			return new ClassProxy(
+				clazz.getSimpleName(),
+				Type.getType(clazz),
+				clazz.getModifiers(),
+				clazz.getPackage().getName()
+			);
+		else
+			return new ClassProxy(
+				clazz.getSimpleName(),
+				Type.getType(clazz),
+				clazz.getModifiers(),
+				from(clazz.getEnclosingClass())
+			);
+	}
+
+	/**
+	 * Returns a new instance of {@link ClassProxy.Builder}.
+	 * @param name the name of the class
+	 * @return the builder object for class proxies
+	 */
+	public static Builder builder(String name) {
+		return new Builder(name);
+	}
+
+	/**
+	 * A builder object for {@link ClassProxy}.
+	 */
+	public static class Builder extends AbstractProxy.Builder<ClassProxy> {
+		
+		private ClassProxy containerClass;
+		
+		/**
+		 * The constructor of the builder, used only internally.
+		 * @param name the "simple name" of the class
+		 */
+		Builder(String name) {
+			super(name);
+			this.containerClass = null;
+		}
+
+		/**
+		 * Sets this class as an inner class and sets the containing
+		 * class to the given class object.
+		 * @param containerClass the {@link Class} representing the
+		 *                       container class
+		 * @return the builder's state after the change
+		 */
+		public Builder setContainerClass(Class<?> containerClass) {
+			this.containerClass = ClassProxy.from(containerClass);
+			return this;
+		}
+
+		/**
+		 * Sets this class as an inner class and sets the containing
+		 * class to the given proxy.
+		 * @param containerClass the {@link ClassProxy} representing
+		 *                         the container class
+		 * @return the builder's state after the change
+		 */
+		public Builder setContainerClass(ClassProxy containerClass) {
+			this.containerClass = containerClass;
+			return this;
+		}
+
+		/**
+		 * Sets this class as an inner class and builds a {@link ClassProxy}
+		 * from the given parent and modifiers.
+		 * @param parentFQN  the fully qualified name of the parent
+		 * @return the builder's state after the change
+		 */
+		public Builder setParent(String parentFQN, int modifiers) {
+			return this.setContainerClass(ClassProxy.from(parentFQN, modifiers));
+		}
+
+		/**
+		 * Sets this class as an inner class and builds a {@link ClassProxy}
+		 * from the given parent.
+		 * @param parentFQN  the fully qualified name of the parent
+		 * @return the builder's state after the change
+		 */
+		@Override
+		public Builder setParent(String parentFQN) {
+			return this.setParent(parentFQN, 0);
+		}
+
+		/**
+		 * Builds a {@link ClassProxy} of the given kind.
+		 * @return the built {@link ClassProxy}
+		 */
+		@Override
+		public ClassProxy build() {
+			if(this.containerClass == null)
+				return new ClassProxy(this.name, this.type, this.modifiers, this.parent);
+			else return new ClassProxy(this.name, this.type, this.modifiers, this.containerClass);
+		}
+	}
+}
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