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// Copyright (c) 2012 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.
#include "base/android/jni_android.h"
#include "base/at_exit.h"
#include "base/logging.h"
#include "testing/gtest/include/gtest/gtest.h"
namespace base {
namespace android {
namespace {
const char kJavaLangObject[] = "java/lang/Object";
const char kGetClass[] = "getClass";
const char kToString[] = "toString";
const char kReturningJavaLangClass[] = "()Ljava/lang/Class;";
const char kReturningJavaLangString[] = "()Ljava/lang/String;";
const char* g_last_method;
const char* g_last_jni_signature;
jmethodID g_last_method_id;
const JNINativeInterface* g_previous_functions;
jmethodID GetMethodIDWrapper(JNIEnv* env, jclass clazz, const char* method,
const char* jni_signature) {
g_last_method = method;
g_last_jni_signature = jni_signature;
g_last_method_id = g_previous_functions->GetMethodID(env, clazz, method,
jni_signature);
return g_last_method_id;
}
} // namespace
class JNIAndroidTest : public testing::Test {
protected:
virtual void SetUp() {
JNIEnv* env = AttachCurrentThread();
g_previous_functions = env->functions;
hooked_functions = *g_previous_functions;
env->functions = &hooked_functions;
hooked_functions.GetMethodID = &GetMethodIDWrapper;
}
virtual void TearDown() {
JNIEnv* env = AttachCurrentThread();
env->functions = g_previous_functions;
Reset();
}
void Reset() {
g_last_method = 0;
g_last_jni_signature = 0;
g_last_method_id = NULL;
}
// Needed to cleanup the cached method map in the implementation between
// runs (e.g. if using --gtest_repeat)
base::ShadowingAtExitManager exit_manager;
// From JellyBean release, the instance of this struct provided in JNIEnv is
// read-only, so we deep copy it to allow individual functions to be hooked.
JNINativeInterface hooked_functions;
};
TEST_F(JNIAndroidTest, GetMethodIDFromClassNameCaching) {
JNIEnv* env = AttachCurrentThread();
Reset();
jmethodID id1 = GetMethodIDFromClassName(env, kJavaLangObject, kGetClass,
kReturningJavaLangClass);
EXPECT_STREQ(kGetClass, g_last_method);
EXPECT_STREQ(kReturningJavaLangClass, g_last_jni_signature);
EXPECT_EQ(g_last_method_id, id1);
Reset();
jmethodID id2 = GetMethodIDFromClassName(env, kJavaLangObject, kGetClass,
kReturningJavaLangClass);
EXPECT_STREQ(0, g_last_method);
EXPECT_STREQ(0, g_last_jni_signature);
EXPECT_EQ(NULL, g_last_method_id);
EXPECT_EQ(id1, id2);
Reset();
jmethodID id3 = GetMethodIDFromClassName(env, kJavaLangObject, kToString,
kReturningJavaLangString);
EXPECT_STREQ(kToString, g_last_method);
EXPECT_STREQ(kReturningJavaLangString, g_last_jni_signature);
EXPECT_EQ(g_last_method_id, id3);
}
namespace {
base::subtle::AtomicWord g_atomic_id = 0;
int LazyMethodIDCall(JNIEnv* env, jclass clazz, int p) {
jmethodID id = base::android::MethodID::LazyGet<
base::android::MethodID::TYPE_STATIC>(
env, clazz,
"abs",
"(I)I",
&g_atomic_id);
return env->CallStaticIntMethod(clazz, id, p);
}
int MethodIDCall(JNIEnv* env, jclass clazz, jmethodID id, int p) {
return env->CallStaticIntMethod(clazz, id, p);
}
} // namespace
TEST(JNIAndroidMicrobenchmark, MethodId) {
JNIEnv* env = AttachCurrentThread();
ScopedJavaLocalRef<jclass> clazz(GetClass(env, "java/lang/Math"));
base::Time start_lazy = base::Time::Now();
int o = 0;
for (int i = 0; i < 1024; ++i)
o += LazyMethodIDCall(env, clazz.obj(), i);
base::Time end_lazy = base::Time::Now();
jmethodID id = reinterpret_cast<jmethodID>(g_atomic_id);
base::Time start = base::Time::Now();
for (int i = 0; i < 1024; ++i)
o += MethodIDCall(env, clazz.obj(), id, i);
base::Time end = base::Time::Now();
// On a Galaxy Nexus, results were in the range of:
// JNI LazyMethodIDCall (us) 1984
// JNI MethodIDCall (us) 1861
LOG(ERROR) << "JNI LazyMethodIDCall (us) " <<
base::TimeDelta(end_lazy - start_lazy).InMicroseconds();
LOG(ERROR) << "JNI MethodIDCall (us) " <<
base::TimeDelta(end - start).InMicroseconds();
LOG(ERROR) << "JNI " << o;
}
} // namespace android
} // namespace base
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