Add documentation

1 files changed, 44 insertions, 0 deletions

diff --git a/src/main/java/moe/nea/modernjava/launch/util/ObjectHolderRefCompanion.java b/src/main/java/moe/nea/modernjava/launch/util/ObjectHolderRefCompanion.java
new file mode 100644
index 0000000..15f9450
--- /dev/null
+++ b/src/main/java/moe/nea/modernjava/launch/util/ObjectHolderRefCompanion.java
@@ -0,0 +1,44 @@
+package moe.nea.modernjava.launch.util;
+
+import moe.nea.modernjava.launch.transform.TransObjectHolderRef;
+import sun.misc.Unsafe;
+
+import java.lang.reflect.Field;
+
+/**
+ * A companion to my transformations from {@link TransObjectHolderRef} to avoid
+ * having to write all of this out in bytecode.
+ */
+public class ObjectHolderRefCompanion {
+    private static Unsafe unsafe;
+
+    static {
+        try {
+            final Field unsafeField = Unsafe.class.getDeclaredField("theUnsafe");
+            unsafeField.setAccessible(true);
+            unsafe = (Unsafe) unsafeField.get(null);
+        } catch (Exception ex) {
+            ex.printStackTrace();
+        }
+    }
+
+    /**
+     * A noop to have a jump target for the reflection factories.
+     */
+    public static void makeFieldWritable(Field f) {
+        String s = "Doing nothing. We will use unsafe to set the value instead, if possible";
+    }
+
+    /**
+     * Write a value to a static final field.
+     */
+    public static void doFieldWrite(Field field, Object object) throws IllegalAccessException {
+        if (unsafe == null) {
+            field.set(null, object);
+        } else {
+            Object o = unsafe.staticFieldBase(field);
+            long l = unsafe.staticFieldOffset(field);
+            unsafe.putObject(o, l, object);
+        }
+    }
+}