Add the constructors of DirectByteBuffer for old Android

komamitsu · komamitsu · commit b922b87cec7e · 2015-01-31T22:04:40.000+09:00
diff --git a/msgpack-core/src/main/java/org/msgpack/core/buffer/MessageBuffer.java b/msgpack-core/src/main/java/org/msgpack/core/buffer/MessageBuffer.java
@@ -27,10 +27,18 @@ public class MessageBuffer {
     static final Constructor byteBufferConstructor;
 
     static final Class<?> directByteBufferClass;
-    static final boolean isByteBufferConstructorTakesBufferReference;
+    static final DirectBufferConstructorType directBufferConstructorType;
+    static final Method memoryBlockWrapFromJni;
     static final int ARRAY_BYTE_BASE_OFFSET;
     static final int ARRAY_BYTE_INDEX_SCALE;
 
+    enum DirectBufferConstructorType {
+        ARGS_LONG_INT_REF,
+        ARGS_LONG_INT,
+        ARGS_INT_INT,
+        ARGS_MB_INT_INT
+    }
+
     static {
         try {
             // Check java version
@@ -82,19 +90,35 @@ public class MessageBuffer {
             // Find the hidden constructor for DirectByteBuffer
             directByteBufferClass = ClassLoader.getSystemClassLoader().loadClass("java.nio.DirectByteBuffer");
             Constructor directByteBufferConstructor = null;
-            boolean isAcceptReference = true;
+            DirectBufferConstructorType constructorType = null;
+            Method mbWrap = null;
             try {
                 // TODO We should use MethodHandle for Java7, which can avoid the cost of boxing with JIT optimization
                 directByteBufferConstructor = directByteBufferClass.getDeclaredConstructor(long.class, int.class, Object.class);
+                constructorType = DirectBufferConstructorType.ARGS_LONG_INT_REF;
             }
-            catch(NoSuchMethodException e) {
-                // https://android.googlesource.com/platform/libcore/+/master/luni/src/main/java/java/nio/DirectByteBuffer.java
-                // DirectByteBuffer(long address, int capacity)
-                directByteBufferConstructor = directByteBufferClass.getDeclaredConstructor(long.class, int.class);
-                isAcceptReference = false;
+            catch(NoSuchMethodException e0) {
+                try {
+                    // https://android.googlesource.com/platform/libcore/+/master/luni/src/main/java/java/nio/DirectByteBuffer.java
+                    // DirectByteBuffer(long address, int capacity)
+                    directByteBufferConstructor = directByteBufferClass.getDeclaredConstructor(long.class, int.class);
+                    constructorType = DirectBufferConstructorType.ARGS_LONG_INT;
+                } catch (NoSuchMethodException e1) {
+                    try {
+                        directByteBufferConstructor = directByteBufferClass.getDeclaredConstructor(int.class, int.class);
+                        constructorType = DirectBufferConstructorType.ARGS_INT_INT;
+                    } catch (NoSuchMethodException e2) {
+                        Class<?> aClass = Class.forName("java.nio.MemoryBlock");
+                        mbWrap = aClass.getDeclaredMethod("wrapFromJni", int.class, long.class);
+                        mbWrap.setAccessible(true);
+                        directByteBufferConstructor = directByteBufferClass.getDeclaredConstructor(aClass, int.class, int.class);
+                        constructorType = DirectBufferConstructorType.ARGS_MB_INT_INT;
+                    }
+                }
             }
             byteBufferConstructor = directByteBufferConstructor;
-            isByteBufferConstructorTakesBufferReference = isAcceptReference;
+            directBufferConstructorType = constructorType;
+            memoryBlockWrapFromJni = mbWrap;
             if(byteBufferConstructor == null)
                 throw new RuntimeException("Constructor of DirectByteBuffer is not found");
 
@@ -510,10 +534,26 @@ public ByteBuffer toByteBuffer(int index, int length) {
             return ByteBuffer.wrap((byte[]) base, (int) ((address - ARRAY_BYTE_BASE_OFFSET) + index), length);
         }
         try {
-            if(isByteBufferConstructorTakesBufferReference)
-                return (ByteBuffer) byteBufferConstructor.newInstance(address + index, length, reference);
-            else
-                return (ByteBuffer) byteBufferConstructor.newInstance(address + index, length);
+            ByteBuffer bb = null;
+            switch (directBufferConstructorType) {
+                case ARGS_LONG_INT_REF:
+                    bb = (ByteBuffer) byteBufferConstructor.newInstance(address + index, length, reference);
+                    break;
+                case ARGS_LONG_INT:
+                    bb = (ByteBuffer) byteBufferConstructor.newInstance(address + index, length);
+                    break;
+                case ARGS_INT_INT:
+                    bb = (ByteBuffer) byteBufferConstructor.newInstance((int)address + index, length);
+                    break;
+                case ARGS_MB_INT_INT:
+                    bb = (ByteBuffer) byteBufferConstructor.newInstance(
+                            memoryBlockWrapFromJni.invoke(null, address + index, length),
+                            length, 0);
+                    break;
+                default:
+                    throw new IllegalStateException("Unexpected value");
+            }
+            return bb;
         }
         catch(Throwable e) {
             // Convert checked exception to unchecked exception
diff --git a/msgpack-core/src/test/scala/org/msgpack/core/buffer/MessageBufferTest.scala b/msgpack-core/src/test/scala/org/msgpack/core/buffer/MessageBufferTest.scala
@@ -112,6 +112,18 @@ class MessageBufferTest extends MessagePackSpec {
 
     }
 
+    "convert to ByteBuffer" in {
+      for (t <- Seq(
+        MessageBuffer.newBuffer(10),
+        MessageBuffer.newDirectBuffer(10),
+        MessageBuffer.newOffHeapBuffer(10))
+      ) {
+        val bb = t.toByteBuffer
+        bb.position shouldBe 0
+        bb.limit shouldBe 10
+        bb.capacity shouldBe 10
+      }
+    }
   }
 
 }

Original file line number	Diff line number	Diff line change
`@@ -112,6 +112,18 @@ class MessageBufferTest extends MessagePackSpec {`
`112`	`112`
`113`	`113`	`}`
`114`	`114`
	`115`	`+ "convert to ByteBuffer" in {`
	`116`	`+ for (t <- Seq(`
	`117`	`+ MessageBuffer.newBuffer(10),`
	`118`	`+ MessageBuffer.newDirectBuffer(10),`
	`119`	`+ MessageBuffer.newOffHeapBuffer(10))`
	`120`	`+ ) {`
	`121`	`+ val bb = t.toByteBuffer`
	`122`	`+ bb.position shouldBe 0`
	`123`	`+ bb.limit shouldBe 10`
	`124`	`+ bb.capacity shouldBe 10`
	`125`	`+ }`
	`126`	`+ }`
`115`	`127`	`}`
`116`	`128`
`117`	`129`	`}`