From 430efe56334e2d3b3892edaf13c9a5e5a71df81f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Florian=20N=C3=BCcke?= <florian@nuecke.de>
Date: Tue, 15 Sep 2020 18:47:12 +0200
Subject: [PATCH] Moved Unsafe access into utility class.

---
 .../java/li/cil/circuity/vm/UnsafeGetter.java | 30 +++++++++++++
 .../vm/device/memory/UnsafeMemory.java        | 43 ++++++-------------
 2 files changed, 42 insertions(+), 31 deletions(-)
 create mode 100644 src/main/java/li/cil/circuity/vm/UnsafeGetter.java

diff --git a/src/main/java/li/cil/circuity/vm/UnsafeGetter.java b/src/main/java/li/cil/circuity/vm/UnsafeGetter.java
new file mode 100644
index 00000000..e6f56e1e
--- /dev/null
+++ b/src/main/java/li/cil/circuity/vm/UnsafeGetter.java
@@ -0,0 +1,30 @@
+package li.cil.circuity.vm;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import sun.misc.Unsafe;
+
+import java.lang.reflect.Field;
+
+public final class UnsafeGetter {
+    private static final Logger LOGGER = LogManager.getLogger();
+    private static final Unsafe UNSAFE;
+
+    static {
+        Unsafe instance = null;
+        final Field field;
+        try {
+            field = Unsafe.class.getDeclaredField("theUnsafe");
+            field.setAccessible(true);
+            instance = (Unsafe) field.get(null);
+        } catch (final NoSuchFieldException | IllegalAccessException e) {
+            LOGGER.error(e);
+        }
+
+        UNSAFE = instance;
+    }
+
+    public static Unsafe get() {
+        return UNSAFE;
+    }
+}
diff --git a/src/main/java/li/cil/circuity/vm/device/memory/UnsafeMemory.java b/src/main/java/li/cil/circuity/vm/device/memory/UnsafeMemory.java
index 5fd8afa3..cec9b4f1 100644
--- a/src/main/java/li/cil/circuity/vm/device/memory/UnsafeMemory.java
+++ b/src/main/java/li/cil/circuity/vm/device/memory/UnsafeMemory.java
@@ -2,32 +2,13 @@ package li.cil.circuity.vm.device.memory;
 
 import li.cil.circuity.api.vm.device.memory.PhysicalMemory;
 import li.cil.circuity.api.vm.device.memory.Sizes;
-import org.apache.logging.log4j.LogManager;
-import org.apache.logging.log4j.Logger;
+import li.cil.circuity.vm.UnsafeGetter;
 import sun.misc.Cleaner;
 import sun.misc.Unsafe;
 import sun.misc.VM;
 
-import java.lang.reflect.Field;
-
 public final class UnsafeMemory implements PhysicalMemory {
-    private static final Logger LOGGER = LogManager.getLogger();
-
-    private static final Unsafe unsafe;
-
-    static {
-        Unsafe instance = null;
-        final Field field;
-        try {
-            field = Unsafe.class.getDeclaredField("theUnsafe");
-            field.setAccessible(true);
-            instance = (Unsafe) field.get(null);
-        } catch (final NoSuchFieldException | IllegalAccessException e) {
-            LOGGER.error(e);
-        }
-
-        unsafe = instance;
-    }
+    private static final Unsafe UNSAFE = UnsafeGetter.get();
 
     private final long address;
     private final long size;
@@ -40,13 +21,13 @@ public final class UnsafeMemory implements PhysicalMemory {
         // Handling for page aligned memory taken from DirectByteBuffer.
 
         final boolean isAligned = VM.isDirectMemoryPageAligned();
-        final int pageSize = unsafe.pageSize();
+        final int pageSize = UNSAFE.pageSize();
 
         this.size = Math.max(4L, (long) size + (isAligned ? pageSize : 0));
 
-        final long base = unsafe.allocateMemory(this.size);
+        final long base = UNSAFE.allocateMemory(this.size);
 
-        unsafe.setMemory(base, this.size, (byte) 0);
+        UNSAFE.setMemory(base, this.size, (byte) 0);
 
         if (isAligned && (base % pageSize != 0)) {
             address = base + pageSize - (base & (pageSize - 1));
@@ -71,13 +52,13 @@ public final class UnsafeMemory implements PhysicalMemory {
         assert offset >= 0 && offset < size;
         switch (sizeLog2) {
             case Sizes.SIZE_8_LOG2:
-                return unsafe.getByte(address + offset);
+                return UNSAFE.getByte(address + offset);
             case Sizes.SIZE_16_LOG2:
                 assert (offset & 0b1) == 0;
-                return unsafe.getShort(address + offset);
+                return UNSAFE.getShort(address + offset);
             case Sizes.SIZE_32_LOG2:
                 assert (offset & 0b11) == 0;
-                return unsafe.getInt(address + offset);
+                return UNSAFE.getInt(address + offset);
             default:
                 throw new IllegalArgumentException();
         }
@@ -88,15 +69,15 @@ public final class UnsafeMemory implements PhysicalMemory {
         assert offset >= 0 && offset < size;
         switch (sizeLog2) {
             case Sizes.SIZE_8_LOG2:
-                unsafe.putByte(address + offset, (byte) value);
+                UNSAFE.putByte(address + offset, (byte) value);
                 break;
             case Sizes.SIZE_16_LOG2:
                 assert (offset & 0b1) == 0;
-                unsafe.putShort(address + offset, (short) value);
+                UNSAFE.putShort(address + offset, (short) value);
                 break;
             case Sizes.SIZE_32_LOG2:
                 assert (offset & 0b11) == 0;
-                unsafe.putInt(address + offset, value);
+                UNSAFE.putInt(address + offset, value);
                 break;
             default:
                 throw new IllegalArgumentException();
@@ -113,7 +94,7 @@ public final class UnsafeMemory implements PhysicalMemory {
         @Override
         public void run() {
             if (address != 0) {
-                unsafe.freeMemory(address);
+                UNSAFE.freeMemory(address);
                 address = 0;
             }
         }