ASM-API: Implement java identifiers as helpers

The implementation contains class, method and field identifiers. The class identifier is extendable to provide flexibility for the architecture. The identifiers are helpers since they help us orgnaize what to transform. The identifiers support any class and they're not stricted to Minecraft classes only.

Author: iHDeveloper

asm-api/src/main/java/codes/biscuit/skyblockaddons/asm/api/helper/TransformClassHelper.java

@@ -0,0 +1,31 @@
+package codes.biscuit.skyblockaddons.asm.api.helper;
+
+import lombok.Getter;
+
+/**
+ * An identifier for a class to transform
+ *
+ * @author iHDeveloper
+ */
+public abstract class TransformClassHelper {
+
+    /**
+     * @return The name used for the owner of a field or method, or a field type.
+     */
+    public final String getNameAsOwner() {
+        return "L" + getName() + ";";
+    }
+
+    /**
+     * @return The name used to identify this class
+     */
+    public String getTransformerName() {
+        // The regex matches single slash or multiple and replace them with one dot
+        return getName().replaceAll("(\\/)+", ".");
+    }
+
+    /**
+     * @return The raw name of the class
+     */
+    public abstract String getName();
+}

asm-api/src/main/java/codes/biscuit/skyblockaddons/asm/api/helper/TransformFieldHelper.java

@@ -0,0 +1,77 @@
+package codes.biscuit.skyblockaddons.asm.api.helper;
+
+import lombok.Getter;
+import org.objectweb.asm.Opcodes;
+import org.objectweb.asm.tree.FieldInsnNode;
+
+/**
+ * An identifier for a field to transform
+ *
+ * @author iHDeveloper
+ */
+@Getter
+public class TransformFieldHelper {
+
+    private final TransformClassHelper owner;
+    private final String name;
+    private String type;
+
+    /**
+     * Create a field helper to help the transformation process
+     *
+     * @param owner The owner of the field
+     * @param name The name of the field
+     * @param type A non-class field type {@link TransformFieldTypes}
+     */
+    public TransformFieldHelper(TransformClassHelper owner, String name, char type) {
+        this(owner, name, "");
+        this.type = "" + type;
+    }
+
+    /**
+     * Create a field helper to help the transformation process
+     *
+     * @param owner The owner of the field
+     * @param name The name of the field
+     * @param type A class helper if the field type is class
+     */
+    public TransformFieldHelper(TransformClassHelper owner, String name, TransformClassHelper type) {
+        this(owner, name, type.getNameAsOwner());
+    }
+
+    /**
+     * Create a field helper to help the transformation process
+     *
+     * @param owner The owner of the field
+     * @param name The name of the field
+     * @param type The raw name of the class
+     */
+    public TransformFieldHelper(TransformClassHelper owner, String name, String type) {
+        this.owner = owner;
+        this.name = name;
+        this.type = "L" + type + ";";
+    }
+
+    /**
+     * Generate the get field instruction of the field
+     *
+     * @return An instruction node of the get field instruction
+     */
+    public FieldInsnNode createGetInstruction() {
+        return new FieldInsnNode(Opcodes.GETFIELD, owner.getNameAsOwner(), name, type);
+    }
+
+    /**
+     * Generate the put instruction of the field
+     *
+     * @return An instruction node of the put field instruction
+     */
+    public FieldInsnNode createPutInstruction() {
+        return new FieldInsnNode(Opcodes.PUTFIELD, owner.getNameAsOwner(), name, type);
+    }
+
+    public boolean equals(FieldInsnNode insnNode) {
+        return name.equals(insnNode.name) && type.equals(insnNode.desc);
+    }
+
+}

asm-api/src/main/java/codes/biscuit/skyblockaddons/asm/api/helper/TransformFieldTypes.java

@@ -0,0 +1,12 @@
+package codes.biscuit.skyblockaddons.asm.api.helper;
+
+public final class TransformFieldTypes {
+    public static final char BYTE = 'B';
+    public static final char CHAR = 'C';
+    public static final char DOUBLE = 'D';
+    public static final char FLOAT = 'F';
+    public static final char INT = 'I';
+    public static final char LONG = 'j';
+    public static final char SHORT = 'S';
+    public static final char BOOLEAN = 'Z';
+}

asm-api/src/main/java/codes/biscuit/skyblockaddons/asm/api/helper/TransformMethodHelper.java

@@ -0,0 +1,125 @@
+package codes.biscuit.skyblockaddons.asm.api.helper;
+
+import lombok.Getter;
+import org.objectweb.asm.Opcodes;
+import org.objectweb.asm.tree.MethodInsnNode;
+import org.objectweb.asm.tree.MethodNode;
+
+/**
+ * An identifier for a method to transform
+ *
+ * @author iHDeveloper
+ */
+@Getter
+public class TransformMethodHelper {
+
+    /**
+     * Represents the constructor of the class
+     */
+    public static final TransformMethodHelper INIT = new TransformMethodHelper("<init>", "<init>");
+
+    private final String name;
+    private String type;
+    private final String[] parameters;
+    private final boolean ioException;
+
+    /**
+     * Create a method with name and void as return type
+     *
+     * @param name The name of the method
+     */
+    public TransformMethodHelper(String name) {
+        this(name, null);
+    }
+
+    /**
+     * Create a method with name and non-class return type
+     *
+     * @param name The name of the method
+     * @param type A non-class field type {@link TransformFieldTypes}
+     */
+    public TransformMethodHelper(String name, char type) {
+        this(name, "");
+        this.type = "" + type;
+    }
+
+    /**
+     * Create a method with name and class as return type
+     *
+     * @param name The name of the method
+     * @param type A class as return type
+     */
+    public TransformMethodHelper(String name, String type) {
+        this(name, type, new String[0]);
+    }
+
+    /**
+     * Create a method with name, class as return type and parameters
+     *
+     * @param name The name of the method
+     * @param type A class as return type
+     * @param parameters The parameters of the method
+     */
+    public TransformMethodHelper(String name, String type, String[] parameters) {
+        this(name, type, parameters, false);
+    }
+
+    /**
+     * Create a method with name, class as return type and parameters
+     *
+     * @param name The name of the method
+     * @param type A class as return type
+     * @param parameters The parameters of the method
+     * @param ioException Does the method throw an IO exception
+     */
+    public TransformMethodHelper(String name, String type, String[] parameters, boolean ioException) {
+        this.name = name;
+        this.type = type == null ? null : "L" + type + ";";
+        this.parameters = parameters;
+        this.ioException = ioException;
+    }
+
+    /**
+     * Generate a assembly method node of the method
+     *
+     * @return The generated node of the method
+     */
+    public final MethodNode createMethodNode() {
+        return new MethodNode(Opcodes.ACC_PUBLIC, name, getDescriptor(), null, getExceptions());
+    }
+
+    public boolean equals(MethodInsnNode insnNode) {
+        return name.equals(insnNode.name) && getDescriptor().equals(insnNode.desc);
+    }
+
+    public boolean equals(MethodNode node) {
+        return name.equals(node.name) && (getDescriptor().equals(node.desc) || this == INIT);
+    }
+
+    /**
+     * Build a descriptor from the method parameters and result
+     *
+     * @return Method Descriptor
+     */
+    public String getDescriptor() {
+        StringBuilder builder = new StringBuilder();
+        builder.append("(");
+        for (String param : parameters) {
+            builder.append(param);
+        }
+        builder.append(")");
+        if (type == null) builder.append("V");
+        else builder.append(type);
+        return builder.toString();
+    }
+
+    /**
+     * Exceptions thrown by the method
+     *
+     * @return A list of exceptions
+     */
+    public String[] getExceptions() {
+        if (ioException) return new String[0];
+        return new String[] { "java/io/IOException" };
+    }
+}