libbinder_ndk: to/fromJavaBinder

This allows for a conversion between android.os.IBinder and AIBinder.

Bug: 111445392
Test: android.binder.cts

Change-Id: Icd3949d298bf602f7d24dc5ec92048df902095cb
diff --git a/libs/binder/ndk/ibinder_jni.cpp b/libs/binder/ndk/ibinder_jni.cpp
new file mode 100644
index 0000000..baea2e8
--- /dev/null
+++ b/libs/binder/ndk/ibinder_jni.cpp
@@ -0,0 +1,42 @@
+/*
+ * Copyright (C) 2018 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <android/binder_ibinder_jni.h>
+#include "ibinder_internal.h"
+
+#include <android_util_Binder.h>
+
+using ::android::IBinder;
+using ::android::ibinderForJavaObject;
+using ::android::javaObjectForIBinder;
+using ::android::sp;
+
+AIBinder* AIBinder_fromJavaBinder(JNIEnv* env, jobject binder) {
+    sp<IBinder> ibinder = ibinderForJavaObject(env, binder);
+
+    sp<AIBinder> cbinder = ABpBinder::lookupOrCreateFromBinder(ibinder);
+    AIBinder_incStrong(cbinder.get());
+
+    return cbinder.get();
+}
+
+jobject AIBinder_toJavaBinder(JNIEnv* env, AIBinder* binder) {
+    if (binder == nullptr) {
+        return nullptr;
+    }
+
+    return javaObjectForIBinder(env, binder->getBinder());
+}