src/native/java_lang_Class.cc

/*
 * 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_;
  }
}

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;
  }
  const DexFile* dex_file = dex_cache->GetDexFile();
  if (dex_file == NULL) {
    return NULL;
  }
  return dex_file->GetDexObject(env);
}

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 JNINativeMethod gMethods[] = {
  NATIVE_METHOD(Class, classForName, "(Ljava/lang/String;ZLjava/lang/ClassLoader;)Ljava/lang/Class;"),
  NATIVE_METHOD(Class, getAnnotationDirectoryOffset, "()I"),
  NATIVE_METHOD(Class, getDex, "()Lcom/android/dex/Dex;"),
  NATIVE_METHOD(Class, getNameNative, "()Ljava/lang/String;"),
  NATIVE_METHOD(Class, getProxyInterfaces, "()[Ljava/lang/Class;"),
};

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

}  // namespace art