src/native/java_lang_Class.cc - platform/art - Git at Google

 /*
  * Copyright (C) 2008 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 "class_linker.h"
 #include "class_loader.h"
 #include "jni_internal.h"
 #include "nth_caller_visitor.h"
 #include "object.h"
 #include "object_utils.h"
 #include "scoped_thread_state_change.h"
 #include "ScopedLocalRef.h"
 #include "ScopedUtfChars.h"
 #include "well_known_classes.h"

 namespace art {

 static Class* DecodeClass(const ScopedObjectAccess& soa, jobject java_class)
     SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
   Class* c = soa.Decode<Class*>(java_class);
   DCHECK(c != NULL);
   DCHECK(c->IsClass());
   // TODO: we could EnsureInitialized here, rather than on every reflective get/set or invoke .
   // For now, we conservatively preserve the old dalvik behavior. A quick "IsInitialized" check
   // every time probably doesn't make much difference to reflection performance anyway.
   return c;
 }

 // "name" is in "binary name" format, e.g. "dalvik.system.Debug$1".
 static jclass Class_classForName(JNIEnv* env, jclass, jstring javaName, jboolean initialize, jobject javaLoader) {
   ScopedObjectAccess soa(env);
   ScopedUtfChars name(env, javaName);
   if (name.c_str() == NULL) {
     return NULL;
   }

   // We need to validate and convert the name (from x.y.z to x/y/z).  This
   // is especially handy for array types, since we want to avoid
   // auto-generating bogus array classes.
   if (!IsValidBinaryClassName(name.c_str())) {
     Thread::Current()->ThrowNewExceptionF("Ljava/lang/ClassNotFoundException;",
         "Invalid name: %s", name.c_str());
     return NULL;
   }

   std::string descriptor(DotToDescriptor(name.c_str()));
   ClassLoader* class_loader = soa.Decode<ClassLoader*>(javaLoader);
   ClassLinker* class_linker = Runtime::Current()->GetClassLinker();
   Class* c = class_linker->FindClass(descriptor.c_str(), class_loader);
   if (c == NULL) {
     ScopedLocalRef<jthrowable> cause(env, env->ExceptionOccurred());
     env->ExceptionClear();
     jthrowable cnfe = reinterpret_cast<jthrowable>(env->NewObject(WellKnownClasses::java_lang_ClassNotFoundException,
                                                                   WellKnownClasses::java_lang_ClassNotFoundException_init,
                                                                   javaName, cause.get()));
     env->Throw(cnfe);
     return NULL;
   }
   if (initialize) {
     class_linker->EnsureInitialized(c, true, true);
   }
   return soa.AddLocalReference<jclass>(c);
 }

 static jint Class_getAnnotationDirectoryOffset(JNIEnv* env, jclass javaClass) {
   ScopedObjectAccess soa(env);
   Class* c = DecodeClass(soa, javaClass);
   if (c->IsPrimitive() || c->IsArrayClass() || c->IsProxyClass()) {
     return 0;  // primitive, array and proxy classes don't have class definitions
   }
   const DexFile::ClassDef* class_def = ClassHelper(c).GetClassDef();
   if (class_def == NULL) {
     return 0;  // not found
   } else {
     return class_def->annotations_off_;
   }
 }

 // TODO: Remove this redundant struct when GCC annotalysis works correctly on top-level functions.
 struct WorkAroundGccAnnotalysisBug {
 template<typename T>
 static jobjectArray ToArray(const ScopedObjectAccessUnchecked& soa, const char* array_class_name,
                             const std::vector<T*>& objects)
     SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
   ScopedLocalRef<jclass> array_class(soa.Env(), soa.Env()->FindClass(array_class_name));
   jobjectArray result = soa.Env()->NewObjectArray(objects.size(), array_class.get(), NULL);
   for (size_t i = 0; i < objects.size(); ++i) {
     ScopedLocalRef<jobject> object(soa.Env(), soa.AddLocalReference<jobject>(objects[i]));
     soa.Env()->SetObjectArrayElement(result, i, object.get());
   }
   return result;
 }
 };
 #define ToArray(a, b, c) WorkAroundGccAnnotalysisBug::ToArray(a, b, c)

 static bool IsVisibleConstructor(AbstractMethod* m, bool public_only) {
   if (public_only && !m->IsPublic()) {
     return false;
   }
   if (m->IsStatic()) {
     return false;
   }
   return m->IsConstructor();
 }

 static jobjectArray Class_getDeclaredConstructors(JNIEnv* env, jclass javaClass, jboolean publicOnly) {
   ScopedObjectAccess soa(env);
   Class* c = DecodeClass(soa, javaClass);
   std::vector<AbstractMethod*> constructors; // TODO: Use Constructor instead of AbstractMethod
   for (size_t i = 0; i < c->NumDirectMethods(); ++i) {
     AbstractMethod* m = c->GetDirectMethod(i);
     if (IsVisibleConstructor(m, publicOnly)) {
       constructors.push_back(m);
     }
   }

   return ToArray(soa, "java/lang/reflect/Constructor", constructors);
 }

 static bool IsVisibleField(Field* f, bool public_only) {
   if (public_only && !f->IsPublic()) {
     return false;
   }
   return true;
 }

 static jobjectArray Class_getDeclaredFields(JNIEnv* env, jclass javaClass, jboolean publicOnly) {
   ScopedObjectAccess soa(env);
   Class* c = DecodeClass(soa, javaClass);
   std::vector<Field*> fields;
   FieldHelper fh;
   for (size_t i = 0; i < c->NumInstanceFields(); ++i) {
     Field* f = c->GetInstanceField(i);
     fh.ChangeField(f);
     if (IsVisibleField(f, publicOnly)) {
       if (fh.GetType() == NULL) {
         DCHECK(env->ExceptionOccurred());
         return NULL;
       }
       fields.push_back(f);
     }
     if (env->ExceptionOccurred()) {
       return NULL;
     }
   }
   for (size_t i = 0; i < c->NumStaticFields(); ++i) {
     Field* f = c->GetStaticField(i);
     fh.ChangeField(f);
     if (IsVisibleField(f, publicOnly)) {
       if (fh.GetType() == NULL) {
         DCHECK(env->ExceptionOccurred());
         return NULL;
       }
       fields.push_back(f);
     }
     if (env->ExceptionOccurred()) {
       return NULL;
     }
   }

   return ToArray(soa, "java/lang/reflect/Field", fields);
 }

 static bool IsVisibleMethod(AbstractMethod* m, bool public_only) {
   if (public_only && !m->IsPublic()) {
     return false;
   }
   if (m->IsConstructor()) {
     return false;
   }
   if (m->IsMiranda()) {
     return false;
   }
   return true;
 }

 static jobjectArray Class_getDeclaredMethods(JNIEnv* env, jclass javaClass, jboolean publicOnly) {
   ScopedObjectAccess soa(env);
   Class* c = DecodeClass(soa, javaClass);
   if (c == NULL) {
     return NULL;
   }

   std::vector<AbstractMethod*> methods;
   MethodHelper mh;
   for (size_t i = 0; i < c->NumVirtualMethods(); ++i) {
     AbstractMethod* m = c->GetVirtualMethod(i);
     mh.ChangeMethod(m);
     if (IsVisibleMethod(m, publicOnly)) {
       // TODO: the use of GetParameterTypes creates an unused array here.
       if (mh.GetReturnType() == NULL || mh.GetParameterTypes(soa.Self()) == NULL) {
         DCHECK(env->ExceptionOccurred());
         return NULL;
       }
       methods.push_back(m);
     }
     if (env->ExceptionOccurred()) {
       return NULL;
     }
   }
   for (size_t i = 0; i < c->NumDirectMethods(); ++i) {
     AbstractMethod* m = c->GetDirectMethod(i);
     mh.ChangeMethod(m);
     if (IsVisibleMethod(m, publicOnly)) {
       // TODO: the use of GetParameterTypes creates an unused array here.
       if (mh.GetReturnType() == NULL || mh.GetParameterTypes(soa.Self()) == NULL) {
         DCHECK(env->ExceptionOccurred());
         return NULL;
       }
       methods.push_back(m);
     }
     if (env->ExceptionOccurred()) {
       return NULL;
     }
   }

   return ToArray(soa, "java/lang/reflect/Method", methods);
 }

 static jobject Class_getDex(JNIEnv* env, jobject javaClass) {
   ScopedObjectAccess soa(env);
   Class* c = DecodeClass(soa, javaClass);

   DexCache* dex_cache = c->GetDexCache();
   if (dex_cache == NULL) {
     return NULL;
   }

   return Runtime::Current()->GetClassLinker()->FindDexFile(dex_cache).GetDexObject(env);
 }

 static bool MethodMatches(MethodHelper* mh, const std::string& name, ObjectArray<Class>* arg_array)
     SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
   if (name != mh->GetName()) {
     return false;
   }
   const DexFile::TypeList* m_type_list = mh->GetParameterTypeList();
   uint32_t m_type_list_size = m_type_list == NULL ? 0 : m_type_list->Size();
   uint32_t sig_length = arg_array->GetLength();

   if (m_type_list_size != sig_length) {
     return false;
   }

   for (uint32_t i = 0; i < sig_length; i++) {
     if (mh->GetClassFromTypeIdx(m_type_list->GetTypeItem(i).type_idx_) != arg_array->Get(i)) {
       return false;
     }
   }
   return true;
 }

 static AbstractMethod* FindConstructorOrMethodInArray(ObjectArray<AbstractMethod>* methods,
                                                       const std::string& name,
                                                       ObjectArray<Class>* arg_array)
     SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
   if (methods == NULL) {
     return NULL;
   }
   AbstractMethod* result = NULL;
   MethodHelper mh;
   for (int32_t i = 0; i < methods->GetLength(); ++i) {
     AbstractMethod* method = methods->Get(i);
     mh.ChangeMethod(method);
     if (method->IsMiranda() || !MethodMatches(&mh, name, arg_array)) {
       continue;
     }

     result = method;

     // Covariant return types permit the class to define multiple
     // methods with the same name and parameter types. Prefer to return
     // a non-synthetic method in such situations. We may still return
     // a synthetic method to handle situations like escalated visibility.
     if (!method->IsSynthetic()) {
         break;
     }
   }
   return result;
 }

 static jobject Class_getDeclaredConstructorOrMethod(JNIEnv* env, jclass javaClass, jstring javaName,
                                                     jobjectArray javaArgs) {
   ScopedObjectAccess soa(env);
   Class* c = DecodeClass(soa, javaClass);
   std::string name(soa.Decode<String*>(javaName)->ToModifiedUtf8());
   ObjectArray<Class>* arg_array = soa.Decode<ObjectArray<Class>*>(javaArgs);

   AbstractMethod* m = FindConstructorOrMethodInArray(c->GetDirectMethods(), name, arg_array);
   if (m == NULL) {
     m = FindConstructorOrMethodInArray(c->GetVirtualMethods(), name, arg_array);
   }

   if (m != NULL) {
     return soa.AddLocalReference<jobject>(m);
   } else {
     return NULL;
   }
 }

 static jobject Class_getDeclaredFieldNative(JNIEnv* env, jclass java_class, jobject jname) {
   ScopedObjectAccess soa(env);
   Class* c = DecodeClass(soa, java_class);
   String* name = soa.Decode<String*>(jname);
   DCHECK(name->GetClass()->IsStringClass());

   FieldHelper fh;
   for (size_t i = 0; i < c->NumInstanceFields(); ++i) {
     Field* f = c->GetInstanceField(i);
     fh.ChangeField(f);
     if (name->Equals(fh.GetName())) {
       if (fh.GetType() == NULL) {
         DCHECK(env->ExceptionOccurred());
         return NULL;
       }
       return soa.AddLocalReference<jclass>(f);
     }
   }
   for (size_t i = 0; i < c->NumStaticFields(); ++i) {
     Field* f = c->GetStaticField(i);
     fh.ChangeField(f);
     if (name->Equals(fh.GetName())) {
       if (fh.GetType() == NULL) {
         DCHECK(env->ExceptionOccurred());
         return NULL;
       }
       return soa.AddLocalReference<jclass>(f);
     }
   }
   return NULL;
 }

 static jstring Class_getNameNative(JNIEnv* env, jobject javaThis) {
   ScopedObjectAccess soa(env);
   Class* c = DecodeClass(soa, javaThis);
   return soa.AddLocalReference<jstring>(c->ComputeName());
 }

 static jobjectArray Class_getProxyInterfaces(JNIEnv* env, jobject javaThis) {
   ScopedObjectAccess soa(env);
   SynthesizedProxyClass* c = down_cast<SynthesizedProxyClass*>(DecodeClass(soa, javaThis));
   return soa.AddLocalReference<jobjectArray>(c->GetInterfaces()->Clone(soa.Self()));
 }

 static jboolean Class_isAssignableFrom(JNIEnv* env, jobject javaLhs, jclass javaRhs) {
   ScopedObjectAccess soa(env);
   Class* lhs = DecodeClass(soa, javaLhs);
   Class* rhs = soa.Decode<Class*>(javaRhs); // Can be null.
   if (rhs == NULL) {
     soa.Self()->ThrowNewException("Ljava/lang/NullPointerException;", "class == null");
     return JNI_FALSE;
   }
   return lhs->IsAssignableFrom(rhs) ? JNI_TRUE : JNI_FALSE;
 }

 static jobject Class_newInstanceImpl(JNIEnv* env, jobject javaThis) {
   ScopedObjectAccess soa(env);
   Class* c = DecodeClass(soa, javaThis);
   if (c->IsPrimitive() || c->IsInterface() || c->IsArrayClass() || c->IsAbstract()) {
     soa.Self()->ThrowNewExceptionF("Ljava/lang/InstantiationException;",
         "Class %s can not be instantiated", PrettyDescriptor(ClassHelper(c).GetDescriptor()).c_str());
     return NULL;
   }

   if (!Runtime::Current()->GetClassLinker()->EnsureInitialized(c, true, true)) {
     return NULL;
   }

   AbstractMethod* init = c->FindDeclaredDirectMethod("<init>", "()V");
   if (init == NULL) {
     soa.Self()->ThrowNewExceptionF("Ljava/lang/InstantiationException;",
         "Class %s has no default <init>()V constructor", PrettyDescriptor(ClassHelper(c).GetDescriptor()).c_str());
     return NULL;
   }

   // Verify access from the call site.
   //
   // First, make sure the method invoking Class.newInstance() has permission
   // to access the class.
   //
   // Second, make sure it has permission to invoke the constructor.  The
   // constructor must be public or, if the caller is in the same package,
   // have package scope.

   NthCallerVisitor visitor(soa.Self()->GetManagedStack(), soa.Self()->GetTraceStack(), 2);
   visitor.WalkStack();
   Class* caller_class = visitor.caller->GetDeclaringClass();

   ClassHelper caller_ch(caller_class);
   if (!caller_class->CanAccess(c)) {
     soa.Self()->ThrowNewExceptionF("Ljava/lang/IllegalAccessException;",
         "Class %s is not accessible from class %s",
         PrettyDescriptor(ClassHelper(c).GetDescriptor()).c_str(),
         PrettyDescriptor(caller_ch.GetDescriptor()).c_str());
     return NULL;
   }
   if (!caller_class->CanAccessMember(init->GetDeclaringClass(), init->GetAccessFlags())) {
     soa.Self()->ThrowNewExceptionF("Ljava/lang/IllegalAccessException;",
         "%s is not accessible from class %s",
         PrettyMethod(init).c_str(),
         PrettyDescriptor(caller_ch.GetDescriptor()).c_str());
     return NULL;
   }

   Object* new_obj = c->AllocObject(soa.Self());
   if (new_obj == NULL) {
     DCHECK(soa.Self()->IsExceptionPending());
     return NULL;
   }

   // invoke constructor; unlike reflection calls, we don't wrap exceptions
   jclass java_class = soa.AddLocalReference<jclass>(c);
   jmethodID mid = soa.EncodeMethod(init);
   return env->NewObject(java_class, mid);
 }

 static JNINativeMethod gMethods[] = {
   NATIVE_METHOD(Class, classForName, "(Ljava/lang/String;ZLjava/lang/ClassLoader;)Ljava/lang/Class;"),
   NATIVE_METHOD(Class, getAnnotationDirectoryOffset, "()I"),
   NATIVE_METHOD(Class, getDeclaredConstructorOrMethod, "(Ljava/lang/String;[Ljava/lang/Class;)Ljava/lang/reflect/Member;"),
   NATIVE_METHOD(Class, getDeclaredConstructors, "(Z)[Ljava/lang/reflect/Constructor;"),
   NATIVE_METHOD(Class, getDeclaredFieldNative, "(Ljava/lang/String;)Ljava/lang/reflect/Field;"),
   NATIVE_METHOD(Class, getDeclaredFields, "(Z)[Ljava/lang/reflect/Field;"),
   NATIVE_METHOD(Class, getDeclaredMethods, "(Z)[Ljava/lang/reflect/Method;"),
   NATIVE_METHOD(Class, getDex, "()Lcom/android/dex/Dex;"),
   NATIVE_METHOD(Class, getNameNative, "()Ljava/lang/String;"),
   NATIVE_METHOD(Class, getProxyInterfaces, "()[Ljava/lang/Class;"),
   NATIVE_METHOD(Class, isAssignableFrom, "(Ljava/lang/Class;)Z"),
   NATIVE_METHOD(Class, newInstanceImpl, "()Ljava/lang/Object;"),
 };

 void register_java_lang_Class(JNIEnv* env) {
   REGISTER_NATIVE_METHODS("java/lang/Class");
 }

 }  // namespace art
	/*
	* Copyright (C) 2008 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 "class_linker.h"
	#include "class_loader.h"
	#include "jni_internal.h"
	#include "nth_caller_visitor.h"
	#include "object.h"
	#include "object_utils.h"
	#include "scoped_thread_state_change.h"
	#include "ScopedLocalRef.h"
	#include "ScopedUtfChars.h"
	#include "well_known_classes.h"

	namespace art {

	static Class* DecodeClass(const ScopedObjectAccess& soa, jobject java_class)
	SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
	Class* c = soa.Decode<Class*>(java_class);
	DCHECK(c != NULL);
	DCHECK(c->IsClass());
	// TODO: we could EnsureInitialized here, rather than on every reflective get/set or invoke .
	// For now, we conservatively preserve the old dalvik behavior. A quick "IsInitialized" check
	// every time probably doesn't make much difference to reflection performance anyway.
	return c;
	}

	// "name" is in "binary name" format, e.g. "dalvik.system.Debug$1".
	static jclass Class_classForName(JNIEnv* env, jclass, jstring javaName, jboolean initialize, jobject javaLoader) {
	ScopedObjectAccess soa(env);
	ScopedUtfChars name(env, javaName);
	if (name.c_str() == NULL) {
	return NULL;
	}

	// We need to validate and convert the name (from x.y.z to x/y/z). This
	// is especially handy for array types, since we want to avoid
	// auto-generating bogus array classes.
	if (!IsValidBinaryClassName(name.c_str())) {
	Thread::Current()->ThrowNewExceptionF("Ljava/lang/ClassNotFoundException;",
	"Invalid name: %s", name.c_str());
	return NULL;
	}

	std::string descriptor(DotToDescriptor(name.c_str()));
	ClassLoader* class_loader = soa.Decode<ClassLoader*>(javaLoader);
	ClassLinker* class_linker = Runtime::Current()->GetClassLinker();
	Class* c = class_linker->FindClass(descriptor.c_str(), class_loader);
	if (c == NULL) {
	ScopedLocalRef<jthrowable> cause(env, env->ExceptionOccurred());
	env->ExceptionClear();
	jthrowable cnfe = reinterpret_cast<jthrowable>(env->NewObject(WellKnownClasses::java_lang_ClassNotFoundException,
	WellKnownClasses::java_lang_ClassNotFoundException_init,
	javaName, cause.get()));
	env->Throw(cnfe);
	return NULL;
	}
	if (initialize) {
	class_linker->EnsureInitialized(c, true, true);
	}
	return soa.AddLocalReference<jclass>(c);
	}

	static jint Class_getAnnotationDirectoryOffset(JNIEnv* env, jclass javaClass) {
	ScopedObjectAccess soa(env);
	Class* c = DecodeClass(soa, javaClass);
	if (c->IsPrimitive() \|\| c->IsArrayClass() \|\| c->IsProxyClass()) {
	return 0; // primitive, array and proxy classes don't have class definitions
	}
	const DexFile::ClassDef* class_def = ClassHelper(c).GetClassDef();
	if (class_def == NULL) {
	return 0; // not found
	} else {
	return class_def->annotations_off_;
	}
	}

	// TODO: Remove this redundant struct when GCC annotalysis works correctly on top-level functions.
	struct WorkAroundGccAnnotalysisBug {
	template<typename T>
	static jobjectArray ToArray(const ScopedObjectAccessUnchecked& soa, const char* array_class_name,
	const std::vector<T*>& objects)
	SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
	ScopedLocalRef<jclass> array_class(soa.Env(), soa.Env()->FindClass(array_class_name));
	jobjectArray result = soa.Env()->NewObjectArray(objects.size(), array_class.get(), NULL);
	for (size_t i = 0; i < objects.size(); ++i) {
	ScopedLocalRef<jobject> object(soa.Env(), soa.AddLocalReference<jobject>(objects[i]));
	soa.Env()->SetObjectArrayElement(result, i, object.get());
	}
	return result;
	}
	};
	#define ToArray(a, b, c) WorkAroundGccAnnotalysisBug::ToArray(a, b, c)

	static bool IsVisibleConstructor(AbstractMethod* m, bool public_only) {
	if (public_only && !m->IsPublic()) {
	return false;
	}
	if (m->IsStatic()) {
	return false;
	}
	return m->IsConstructor();
	}

	static jobjectArray Class_getDeclaredConstructors(JNIEnv* env, jclass javaClass, jboolean publicOnly) {
	ScopedObjectAccess soa(env);
	Class* c = DecodeClass(soa, javaClass);
	std::vector<AbstractMethod*> constructors; // TODO: Use Constructor instead of AbstractMethod
	for (size_t i = 0; i < c->NumDirectMethods(); ++i) {
	AbstractMethod* m = c->GetDirectMethod(i);
	if (IsVisibleConstructor(m, publicOnly)) {
	constructors.push_back(m);
	}
	}

	return ToArray(soa, "java/lang/reflect/Constructor", constructors);
	}

	static bool IsVisibleField(Field* f, bool public_only) {
	if (public_only && !f->IsPublic()) {
	return false;
	}
	return true;
	}

	static jobjectArray Class_getDeclaredFields(JNIEnv* env, jclass javaClass, jboolean publicOnly) {
	ScopedObjectAccess soa(env);
	Class* c = DecodeClass(soa, javaClass);
	std::vector<Field*> fields;
	FieldHelper fh;
	for (size_t i = 0; i < c->NumInstanceFields(); ++i) {
	Field* f = c->GetInstanceField(i);
	fh.ChangeField(f);
	if (IsVisibleField(f, publicOnly)) {
	if (fh.GetType() == NULL) {
	DCHECK(env->ExceptionOccurred());
	return NULL;
	}
	fields.push_back(f);
	}
	if (env->ExceptionOccurred()) {
	return NULL;
	}
	}
	for (size_t i = 0; i < c->NumStaticFields(); ++i) {
	Field* f = c->GetStaticField(i);
	fh.ChangeField(f);
	if (IsVisibleField(f, publicOnly)) {
	if (fh.GetType() == NULL) {
	DCHECK(env->ExceptionOccurred());
	return NULL;
	}
	fields.push_back(f);
	}
	if (env->ExceptionOccurred()) {
	return NULL;
	}
	}

	return ToArray(soa, "java/lang/reflect/Field", fields);
	}

	static bool IsVisibleMethod(AbstractMethod* m, bool public_only) {
	if (public_only && !m->IsPublic()) {
	return false;
	}
	if (m->IsConstructor()) {
	return false;
	}
	if (m->IsMiranda()) {
	return false;
	}
	return true;
	}

	static jobjectArray Class_getDeclaredMethods(JNIEnv* env, jclass javaClass, jboolean publicOnly) {
	ScopedObjectAccess soa(env);
	Class* c = DecodeClass(soa, javaClass);
	if (c == NULL) {
	return NULL;
	}

	std::vector<AbstractMethod*> methods;
	MethodHelper mh;
	for (size_t i = 0; i < c->NumVirtualMethods(); ++i) {
	AbstractMethod* m = c->GetVirtualMethod(i);
	mh.ChangeMethod(m);
	if (IsVisibleMethod(m, publicOnly)) {
	// TODO: the use of GetParameterTypes creates an unused array here.
	if (mh.GetReturnType() == NULL \|\| mh.GetParameterTypes(soa.Self()) == NULL) {
	DCHECK(env->ExceptionOccurred());
	return NULL;
	}
	methods.push_back(m);
	}
	if (env->ExceptionOccurred()) {
	return NULL;
	}
	}
	for (size_t i = 0; i < c->NumDirectMethods(); ++i) {
	AbstractMethod* m = c->GetDirectMethod(i);
	mh.ChangeMethod(m);
	if (IsVisibleMethod(m, publicOnly)) {
	// TODO: the use of GetParameterTypes creates an unused array here.
	if (mh.GetReturnType() == NULL \|\| mh.GetParameterTypes(soa.Self()) == NULL) {
	DCHECK(env->ExceptionOccurred());
	return NULL;
	}
	methods.push_back(m);
	}
	if (env->ExceptionOccurred()) {
	return NULL;
	}
	}

	return ToArray(soa, "java/lang/reflect/Method", methods);
	}

	static jobject Class_getDex(JNIEnv* env, jobject javaClass) {
	ScopedObjectAccess soa(env);
	Class* c = DecodeClass(soa, javaClass);

	DexCache* dex_cache = c->GetDexCache();
	if (dex_cache == NULL) {
	return NULL;
	}

	return Runtime::Current()->GetClassLinker()->FindDexFile(dex_cache).GetDexObject(env);
	}

	static bool MethodMatches(MethodHelper* mh, const std::string& name, ObjectArray<Class>* arg_array)
	SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
	if (name != mh->GetName()) {
	return false;
	}
	const DexFile::TypeList* m_type_list = mh->GetParameterTypeList();
	uint32_t m_type_list_size = m_type_list == NULL ? 0 : m_type_list->Size();
	uint32_t sig_length = arg_array->GetLength();

	if (m_type_list_size != sig_length) {
	return false;
	}

	for (uint32_t i = 0; i < sig_length; i++) {
	if (mh->GetClassFromTypeIdx(m_type_list->GetTypeItem(i).type_idx_) != arg_array->Get(i)) {
	return false;
	}
	}
	return true;
	}

	static AbstractMethod* FindConstructorOrMethodInArray(ObjectArray<AbstractMethod>* methods,
	const std::string& name,
	ObjectArray<Class>* arg_array)
	SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
	if (methods == NULL) {
	return NULL;
	}
	AbstractMethod* result = NULL;
	MethodHelper mh;
	for (int32_t i = 0; i < methods->GetLength(); ++i) {
	AbstractMethod* method = methods->Get(i);
	mh.ChangeMethod(method);
	if (method->IsMiranda() \|\| !MethodMatches(&mh, name, arg_array)) {
	continue;
	}

	result = method;

	// Covariant return types permit the class to define multiple
	// methods with the same name and parameter types. Prefer to return
	// a non-synthetic method in such situations. We may still return
	// a synthetic method to handle situations like escalated visibility.
	if (!method->IsSynthetic()) {
	break;
	}
	}
	return result;
	}

	static jobject Class_getDeclaredConstructorOrMethod(JNIEnv* env, jclass javaClass, jstring javaName,
	jobjectArray javaArgs) {
	ScopedObjectAccess soa(env);
	Class* c = DecodeClass(soa, javaClass);
	std::string name(soa.Decode<String*>(javaName)->ToModifiedUtf8());
	ObjectArray<Class>* arg_array = soa.Decode<ObjectArray<Class>*>(javaArgs);

	AbstractMethod* m = FindConstructorOrMethodInArray(c->GetDirectMethods(), name, arg_array);
	if (m == NULL) {
	m = FindConstructorOrMethodInArray(c->GetVirtualMethods(), name, arg_array);
	}

	if (m != NULL) {
	return soa.AddLocalReference<jobject>(m);
	} else {
	return NULL;
	}
	}

	static jobject Class_getDeclaredFieldNative(JNIEnv* env, jclass java_class, jobject jname) {
	ScopedObjectAccess soa(env);
	Class* c = DecodeClass(soa, java_class);
	String* name = soa.Decode<String*>(jname);
	DCHECK(name->GetClass()->IsStringClass());

	FieldHelper fh;
	for (size_t i = 0; i < c->NumInstanceFields(); ++i) {
	Field* f = c->GetInstanceField(i);
	fh.ChangeField(f);
	if (name->Equals(fh.GetName())) {
	if (fh.GetType() == NULL) {
	DCHECK(env->ExceptionOccurred());
	return NULL;
	}
	return soa.AddLocalReference<jclass>(f);
	}
	}
	for (size_t i = 0; i < c->NumStaticFields(); ++i) {
	Field* f = c->GetStaticField(i);
	fh.ChangeField(f);
	if (name->Equals(fh.GetName())) {
	if (fh.GetType() == NULL) {
	DCHECK(env->ExceptionOccurred());
	return NULL;
	}
	return soa.AddLocalReference<jclass>(f);
	}
	}
	return NULL;
	}

	static jstring Class_getNameNative(JNIEnv* env, jobject javaThis) {
	ScopedObjectAccess soa(env);
	Class* c = DecodeClass(soa, javaThis);
	return soa.AddLocalReference<jstring>(c->ComputeName());
	}

	static jobjectArray Class_getProxyInterfaces(JNIEnv* env, jobject javaThis) {
	ScopedObjectAccess soa(env);
	SynthesizedProxyClass* c = down_cast<SynthesizedProxyClass*>(DecodeClass(soa, javaThis));
	return soa.AddLocalReference<jobjectArray>(c->GetInterfaces()->Clone(soa.Self()));
	}

	static jboolean Class_isAssignableFrom(JNIEnv* env, jobject javaLhs, jclass javaRhs) {
	ScopedObjectAccess soa(env);
	Class* lhs = DecodeClass(soa, javaLhs);
	Class* rhs = soa.Decode<Class*>(javaRhs); // Can be null.
	if (rhs == NULL) {
	soa.Self()->ThrowNewException("Ljava/lang/NullPointerException;", "class == null");
	return JNI_FALSE;
	}
	return lhs->IsAssignableFrom(rhs) ? JNI_TRUE : JNI_FALSE;
	}

	static jobject Class_newInstanceImpl(JNIEnv* env, jobject javaThis) {
	ScopedObjectAccess soa(env);
	Class* c = DecodeClass(soa, javaThis);
	if (c->IsPrimitive() \|\| c->IsInterface() \|\| c->IsArrayClass() \|\| c->IsAbstract()) {
	soa.Self()->ThrowNewExceptionF("Ljava/lang/InstantiationException;",
	"Class %s can not be instantiated", PrettyDescriptor(ClassHelper(c).GetDescriptor()).c_str());
	return NULL;
	}

	if (!Runtime::Current()->GetClassLinker()->EnsureInitialized(c, true, true)) {
	return NULL;
	}

	AbstractMethod* init = c->FindDeclaredDirectMethod("<init>", "()V");
	if (init == NULL) {
	soa.Self()->ThrowNewExceptionF("Ljava/lang/InstantiationException;",
	"Class %s has no default <init>()V constructor", PrettyDescriptor(ClassHelper(c).GetDescriptor()).c_str());
	return NULL;
	}

	// Verify access from the call site.
	//
	// First, make sure the method invoking Class.newInstance() has permission
	// to access the class.
	//
	// Second, make sure it has permission to invoke the constructor. The
	// constructor must be public or, if the caller is in the same package,
	// have package scope.

	NthCallerVisitor visitor(soa.Self()->GetManagedStack(), soa.Self()->GetTraceStack(), 2);
	visitor.WalkStack();
	Class* caller_class = visitor.caller->GetDeclaringClass();

	ClassHelper caller_ch(caller_class);
	if (!caller_class->CanAccess(c)) {
	soa.Self()->ThrowNewExceptionF("Ljava/lang/IllegalAccessException;",
	"Class %s is not accessible from class %s",
	PrettyDescriptor(ClassHelper(c).GetDescriptor()).c_str(),
	PrettyDescriptor(caller_ch.GetDescriptor()).c_str());
	return NULL;
	}
	if (!caller_class->CanAccessMember(init->GetDeclaringClass(), init->GetAccessFlags())) {
	soa.Self()->ThrowNewExceptionF("Ljava/lang/IllegalAccessException;",
	"%s is not accessible from class %s",
	PrettyMethod(init).c_str(),
	PrettyDescriptor(caller_ch.GetDescriptor()).c_str());
	return NULL;
	}

	Object* new_obj = c->AllocObject(soa.Self());
	if (new_obj == NULL) {
	DCHECK(soa.Self()->IsExceptionPending());
	return NULL;
	}

	// invoke constructor; unlike reflection calls, we don't wrap exceptions
	jclass java_class = soa.AddLocalReference<jclass>(c);
	jmethodID mid = soa.EncodeMethod(init);
	return env->NewObject(java_class, mid);
	}

	static JNINativeMethod gMethods[] = {
	NATIVE_METHOD(Class, classForName, "(Ljava/lang/String;ZLjava/lang/ClassLoader;)Ljava/lang/Class;"),
	NATIVE_METHOD(Class, getAnnotationDirectoryOffset, "()I"),
	NATIVE_METHOD(Class, getDeclaredConstructorOrMethod, "(Ljava/lang/String;[Ljava/lang/Class;)Ljava/lang/reflect/Member;"),
	NATIVE_METHOD(Class, getDeclaredConstructors, "(Z)[Ljava/lang/reflect/Constructor;"),
	NATIVE_METHOD(Class, getDeclaredFieldNative, "(Ljava/lang/String;)Ljava/lang/reflect/Field;"),
	NATIVE_METHOD(Class, getDeclaredFields, "(Z)[Ljava/lang/reflect/Field;"),
	NATIVE_METHOD(Class, getDeclaredMethods, "(Z)[Ljava/lang/reflect/Method;"),
	NATIVE_METHOD(Class, getDex, "()Lcom/android/dex/Dex;"),
	NATIVE_METHOD(Class, getNameNative, "()Ljava/lang/String;"),
	NATIVE_METHOD(Class, getProxyInterfaces, "()[Ljava/lang/Class;"),
	NATIVE_METHOD(Class, isAssignableFrom, "(Ljava/lang/Class;)Z"),
	NATIVE_METHOD(Class, newInstanceImpl, "()Ljava/lang/Object;"),
	};

	void register_java_lang_Class(JNIEnv* env) {
	REGISTER_NATIVE_METHODS("java/lang/Class");
	}

	} // namespace art