Add AutoJObject and AutoGlobalJObject

base/android/auto_jobject.h

+// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef BASE_ANDROID_AUTO_JOBJECT_H_
+#define BASE_ANDROID_AUTO_JOBJECT_H_
+
+#include <jni.h>
+
+namespace base {
+namespace android {
+
+// A helper class that automatically deletes the local reference to the jobject.

[brettw, 2011/08/01 16:03:54]

Basically the same comments from the other class.

+class AutoJObject {
+ public:
+  // Takes ownership of |obj|.
+  static AutoJObject FromLocalRef(JNIEnv* env, jobject obj);

[steveblock, 2011/08/02 15:05:46]

We could simplify the API by removing this method and making a new public
constructor AutoJObject(JNIEnv, jobject). Marcus, Sami, do you have a
preference?

[bulach, 2011/08/02 15:18:36]

no particular preference, happy to go with the simpler API (I think the original
idea was to have named factory functions rather than different ctors, but I
don't think we needed it in the end..)

[Sami (do not use), 2011/08/02 15:23:49]

I'd be fine with having a new constructor for AutoJObject. Just make sure to
document it well :)

+
+  AutoJObject(const AutoJObject& other);
+  ~AutoJObject();
+
+  JNIEnv* env() const;
+  jobject obj() const;
+  // Releases the local reference to the caller. The caller *must* delete the
+  // local reference when it is done with it.
+  jobject Release();
+
+ private:
+  AutoJObject();  // Not permitted.
+  AutoJObject(JNIEnv* env, jobject obj);
+
+  JNIEnv* env_;
+  jobject obj_;
+};
+
+}  // namespace android
+}  // namespace base
+
+#endif  // BASE_ANDROID_AUTO_JOBJECT_H_