From 9adc1a3526d58f7123a0837d4c5c68eb6a7099dd Mon Sep 17 00:00:00 2001
From: LiuChuliang 刘楚梁 <chuliang.liu@smil.com>
Date: Thu, 18 Jan 2024 16:11:16 +0800
Subject: support bootstrap method coping when using code coping

---
 .../bytecode/BootstrapMethodsAttribute.java        | 103 ++++++++++++++++-----
 1 file changed, 81 insertions(+), 22 deletions(-)

(limited to 'src/main/javassist/bytecode/BootstrapMethodsAttribute.java')

diff --git a/src/main/javassist/bytecode/BootstrapMethodsAttribute.java b/src/main/javassist/bytecode/BootstrapMethodsAttribute.java
index 94a0481f..0fd04cf8 100644
--- a/src/main/javassist/bytecode/BootstrapMethodsAttribute.java
+++ b/src/main/javassist/bytecode/BootstrapMethodsAttribute.java
@@ -2,6 +2,7 @@ package javassist.bytecode;
 
 import java.io.DataInputStream;
 import java.io.IOException;
+import java.util.Arrays;
 import java.util.Map;
 
 public class BootstrapMethodsAttribute extends AttributeInfo {
@@ -35,6 +36,26 @@ public class BootstrapMethodsAttribute extends AttributeInfo {
          * <code>bootstrap_arguments</code>.
          */
         public int[] arguments;
+
+        /**
+         * Makes a copy.  Class names are replaced according to the
+         *          * given <code>Map</code> object.
+         *
+         * @param srcCp     the constant pool table from the source
+         * @param destCp    the constant pool table used bt new copy
+         * @param classnames    pairs of replaced and substituted class names.
+         *
+         * @return new BootstrapMethod
+         */
+        protected BootstrapMethod copy(ConstPool srcCp, ConstPool destCp, Map<String,String> classnames) {
+            int newMethodRef = srcCp.copy(methodRef, destCp, classnames);
+            int[] newArguments = new int[arguments.length];
+
+            for (int i = 0; i < arguments.length; i++)
+                newArguments[i] = srcCp.copy(arguments[i], destCp, classnames);
+
+            return new BootstrapMethod(newMethodRef, newArguments);
+        }
     }
 
     BootstrapMethodsAttribute(ConstPool cp, int n, DataInputStream in)
@@ -51,25 +72,8 @@ public class BootstrapMethodsAttribute extends AttributeInfo {
      */
     public BootstrapMethodsAttribute(ConstPool cp, BootstrapMethod[] methods) {
         super(cp, tag);
-        int size = 2;
-        for (int i = 0; i < methods.length; i++)
-            size += 4 + methods[i].arguments.length * 2;
-
-        byte[] data = new byte[size];
-        ByteArray.write16bit(methods.length, data, 0);    // num_bootstrap_methods
-        int pos = 2;
-        for (int i = 0; i < methods.length; i++) {
-            ByteArray.write16bit(methods[i].methodRef, data, pos);
-            ByteArray.write16bit(methods[i].arguments.length, data, pos + 2);
-            int[] args = methods[i].arguments;
-            pos += 4;
-            for (int k = 0; k < args.length; k++) {
-                ByteArray.write16bit(args[k], data, pos);
-                pos += 2;
-            }
-        }
 
-        set(data);
+        set(convertMethodsToBytes(methods));
     }
 
     /**
@@ -113,12 +117,67 @@ public class BootstrapMethodsAttribute extends AttributeInfo {
         BootstrapMethod[] methods = getMethods();
         ConstPool thisCp = getConstPool();
         for (int i = 0; i < methods.length; i++) {
-            BootstrapMethod m = methods[i];
-            m.methodRef = thisCp.copy(m.methodRef, newCp, classnames);
-            for (int k = 0; k < m.arguments.length; k++)
-                m.arguments[k] = thisCp.copy(m.arguments[k], newCp, classnames);
+            methods[i] = methods[i].copy(thisCp, newCp, classnames);
         }
 
         return new BootstrapMethodsAttribute(newCp, methods);
     }
+
+    /**
+     * add bootstrap method from given <code>ConstPool</code> and <code>BootstrapMethod</code>,
+     * and add it to the specified index. Class names are replaced according to the
+     * given <code>Map</code> object.
+     *
+     * <p>
+     *      if the index less than 0 or large than the origin method length, then throw <code>RuntimeException</code>;<br>
+     *      if the index large or equals to 0 and less or equals to the origin method length,
+     *          then replace the origin method with the new <code>BootstrapMethod srcBm</code> ;<br>
+     *      if the index equals to the origin method length, then append the new <code>BootstrapMethod srcBm</code> at
+     *          the origin methods tail.
+     * </p>
+     *
+     * @param srcCp     the constant pool table of source.
+     * @param srcBm     the bootstrap method of source
+     * @param index     the new method index on bootstrap methods
+     * @param classnames        pairs of replaced and substituted
+     *                          class names.
+     */
+    public void addMethod(ConstPool srcCp, BootstrapMethod srcBm, int index, Map<String,String> classnames) {
+        BootstrapMethod[] methods = getMethods();
+
+        if (index < 0 || index > methods.length) {
+            throw new RuntimeException("index out of range");
+        }
+
+        if (index == methods.length) {
+            BootstrapMethod[] newBmArray = new BootstrapMethod[methods.length + 1];
+            System.arraycopy(methods, 0, newBmArray, 0, methods.length);
+            methods = newBmArray;
+        }
+
+        methods[index] = srcBm.copy(srcCp, getConstPool(), classnames);
+        set(convertMethodsToBytes(methods));
+    }
+
+    private static byte[] convertMethodsToBytes(BootstrapMethod[] methods) {
+        int size = 2;
+        for (int i = 0; i < methods.length; i++)
+            size += 4 + methods[i].arguments.length * 2;
+
+        byte[] data = new byte[size];
+        ByteArray.write16bit(methods.length, data, 0);    // num_bootstrap_methods
+        int pos = 2;
+        for (int i = 0; i < methods.length; i++) {
+            ByteArray.write16bit(methods[i].methodRef, data, pos);
+            ByteArray.write16bit(methods[i].arguments.length, data, pos + 2);
+            int[] args = methods[i].arguments;
+            pos += 4;
+            for (int k = 0; k < args.length; k++) {
+                ByteArray.write16bit(args[k], data, pos);
+                pos += 2;
+            }
+        }
+
+        return data;
+    }
 }
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