base/android/scoped_java_ref_unittest.cc

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "base/android/scoped_java_ref.h"
   6
   7 #include "base/android/jni_android.h"
   8 #include "base/android/jni_string.h"
   9 #include "testing/gtest/include/gtest/gtest.h"
  10
  11 namespace base {
  12 namespace android {
  13
  14 namespace {
  15 int g_local_refs = 0;
  16 int g_global_refs = 0;
  17
  18 const JNINativeInterface* g_previous_functions;
  19
  20 jobject NewGlobalRef(JNIEnv* env, jobject obj) {
  21   ++g_global_refs;
  22   return g_previous_functions->NewGlobalRef(env, obj);
  23 }
  24
  25 void DeleteGlobalRef(JNIEnv* env, jobject obj) {
  26   --g_global_refs;
  27   return g_previous_functions->DeleteGlobalRef(env, obj);
  28 }
  29
  30 jobject NewLocalRef(JNIEnv* env, jobject obj) {
  31   ++g_local_refs;
  32   return g_previous_functions->NewLocalRef(env, obj);
  33 }
  34
  35 void DeleteLocalRef(JNIEnv* env, jobject obj) {
  36   --g_local_refs;
  37   return g_previous_functions->DeleteLocalRef(env, obj);
  38 }
  39 }  // namespace
  40
  41 class ScopedJavaRefTest : public testing::Test {
  42  protected:
  43   void SetUp() override {
  44     g_local_refs = 0;
  45     g_global_refs = 0;
  46     JNIEnv* env = AttachCurrentThread();
  47     g_previous_functions = env->functions;
  48     hooked_functions = *g_previous_functions;
  49     env->functions = &hooked_functions;
  50     // We inject our own functions in JNINativeInterface so we can keep track
  51     // of the reference counting ourselves.
  52     hooked_functions.NewGlobalRef = &NewGlobalRef;
  53     hooked_functions.DeleteGlobalRef = &DeleteGlobalRef;
  54     hooked_functions.NewLocalRef = &NewLocalRef;
  55     hooked_functions.DeleteLocalRef = &DeleteLocalRef;
  56   }
  57
  58   void TearDown() override {
  59     JNIEnv* env = AttachCurrentThread();
  60     env->functions = g_previous_functions;
  61   }
  62   // From JellyBean release, the instance of this struct provided in JNIEnv is
  63   // read-only, so we deep copy it to allow individual functions to be hooked.
  64   JNINativeInterface hooked_functions;
  65 };
  66
  67 // The main purpose of this is testing the various conversions compile.
  68 TEST_F(ScopedJavaRefTest, Conversions) {
  69   JNIEnv* env = AttachCurrentThread();
  70   ScopedJavaLocalRef<jstring> str = ConvertUTF8ToJavaString(env, "string");
  71   ScopedJavaGlobalRef<jstring> global(str);
  72   {
  73     ScopedJavaGlobalRef<jobject> global_obj(str);
  74     ScopedJavaLocalRef<jobject> local_obj(global);
  75     const JavaRef<jobject>& obj_ref1(str);
  76     const JavaRef<jobject>& obj_ref2(global);
  77     EXPECT_TRUE(env->IsSameObject(obj_ref1.obj(), obj_ref2.obj()));
  78     EXPECT_TRUE(env->IsSameObject(global_obj.obj(), obj_ref2.obj()));
  79   }
  80   global.Reset(str);
  81   const JavaRef<jstring>& str_ref = str;
  82   EXPECT_EQ("string", ConvertJavaStringToUTF8(str_ref));
  83   str.Reset();
  84 }
  85
  86 TEST_F(ScopedJavaRefTest, RefCounts) {
  87   JNIEnv* env = AttachCurrentThread();
  88   ScopedJavaLocalRef<jstring> str;
  89   // The ConvertJavaStringToUTF8 below creates a new string that would normally
  90   // return a local ref. We simulate that by starting the g_local_refs count at
  91   // 1.
  92   g_local_refs = 1;
  93   str.Reset(ConvertUTF8ToJavaString(env, "string"));
  94   EXPECT_EQ(1, g_local_refs);
  95   EXPECT_EQ(0, g_global_refs);
  96   {
  97     ScopedJavaGlobalRef<jstring> global_str(str);
  98     ScopedJavaGlobalRef<jobject> global_obj(global_str);
  99     EXPECT_EQ(1, g_local_refs);
 100     EXPECT_EQ(2, g_global_refs);
 101
 102     ScopedJavaLocalRef<jstring> str2(env, str.Release());
 103     EXPECT_EQ(1, g_local_refs);
 104     {
 105       ScopedJavaLocalRef<jstring> str3(str2);
 106       EXPECT_EQ(2, g_local_refs);
 107     }
 108     EXPECT_EQ(1, g_local_refs);
 109     str2.Reset();
 110     EXPECT_EQ(0, g_local_refs);
 111     global_str.Reset();
 112     EXPECT_EQ(1, g_global_refs);
 113     ScopedJavaGlobalRef<jobject> global_obj2(global_obj);
 114     EXPECT_EQ(2, g_global_refs);
 115   }
 116
 117   EXPECT_EQ(0, g_local_refs);
 118   EXPECT_EQ(0, g_global_refs);
 119 }
 120
 121 }  // namespace android
 122 }  // namespace base