Allowing a Java object field to be null in a new JNI helper method.

webrtc/api/java/jni/jni_helpers.cc

 /*
  *  Copyright 2015 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 #include "webrtc/api/java/jni/jni_helpers.h"
@@ skipping 157 matching lines @@
 
 jclass GetObjectClass(JNIEnv* jni, jobject object) {
   jclass c = jni->GetObjectClass(object);
   CHECK_EXCEPTION(jni) << "error during GetObjectClass";
   RTC_CHECK(c) << "GetObjectClass returned NULL";
   return c;
 }
 
 jobject GetObjectField(JNIEnv* jni, jobject object, jfieldID id) {
   jobject o = jni->GetObjectField(object, id);
   CHECK_EXCEPTION(jni) << "error during GetObjectField";

[pthatcher1, 2016/04/11 19:39:29]

Can't you replace this with GetNullableObjectField?

[Taylor Brandstetter, 2016/04/11 23:13:38]

True.

-  RTC_CHECK(o) << "GetObjectField returned NULL";
+  RTC_CHECK(!IsNull(jni, o)) << "GetObjectField returned NULL";
   return o;
 }
 
+jobject GetNullableObjectField(JNIEnv* jni, jobject object, jfieldID id) {
+  jobject o = jni->GetObjectField(object, id);
+  CHECK_EXCEPTION(jni) << "error during GetObjectField";
+  return o;
+}
+
 jstring GetStringField(JNIEnv* jni, jobject object, jfieldID id) {
   return static_cast<jstring>(GetObjectField(jni, object, id));
 }
 
 jlong GetLongField(JNIEnv* jni, jobject object, jfieldID id) {
   jlong l = jni->GetLongField(object, id);
   CHECK_EXCEPTION(jni) << "error during GetLongField";
   return l;
 }
 
@@ skipping 142 matching lines @@
   RTC_CHECK(!AtEnd());
   return value_;
 }
 
 bool Iterable::Iterator::AtEnd() const {
   RTC_CHECK(thread_checker_.CalledOnValidThread());
   return jni_ == nullptr || IsNull(jni_, iterator_);
 }
 
 }  // namespace webrtc_jni