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/*
* Copyright (C) 2018 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.
*/
#ifndef LIBTEXTCLASSIFIER_UTILS_JAVA_JNI_BASE_H_
#define LIBTEXTCLASSIFIER_UTILS_JAVA_JNI_BASE_H_
#include <jni.h>
#include <string>
#include "utils/base/statusor.h"
// When we use a macro as an argument for a macro, an additional level of
// indirection is needed, if the macro argument is used with # or ##.
#define TC3_ADD_QUOTES_HELPER(TOKEN) #TOKEN
#define TC3_ADD_QUOTES(TOKEN) TC3_ADD_QUOTES_HELPER(TOKEN)
#ifndef TC3_PACKAGE_NAME
#define TC3_PACKAGE_NAME com_google_android_textclassifier
#endif
#ifndef TC3_PACKAGE_PATH
#define TC3_PACKAGE_PATH \
"com/google/android/textclassifier/"
#endif
#define TC3_JNI_METHOD_NAME_INTERNAL(package_name, class_name, method_name) \
Java_##package_name##_##class_name##_##method_name
#define TC3_JNI_METHOD_PRIMITIVE(return_type, package_name, class_name, \
method_name) \
JNIEXPORT return_type JNICALL TC3_JNI_METHOD_NAME_INTERNAL( \
package_name, class_name, method_name)
// The indirection is needed to correctly expand the TC3_PACKAGE_NAME macro.
// See the explanation near TC3_ADD_QUOTES macro.
#define TC3_JNI_METHOD2(return_type, package_name, class_name, method_name) \
TC3_JNI_METHOD_PRIMITIVE(return_type, package_name, class_name, method_name)
#define TC3_JNI_METHOD(return_type, class_name, method_name) \
TC3_JNI_METHOD2(return_type, TC3_PACKAGE_NAME, class_name, method_name)
#define TC3_JNI_METHOD_NAME2(package_name, class_name, method_name) \
TC3_JNI_METHOD_NAME_INTERNAL(package_name, class_name, method_name)
#define TC3_JNI_METHOD_NAME(class_name, method_name) \
TC3_JNI_METHOD_NAME2(TC3_PACKAGE_NAME, class_name, method_name)
namespace libtextclassifier3 {
// Returns true if the requested capacity is available.
bool EnsureLocalCapacity(JNIEnv* env, int capacity);
// Returns true if there was an exception. Also it clears the exception.
bool JniExceptionCheckAndClear(JNIEnv* env,
bool print_exception_on_error = true);
// A deleter to be used with std::unique_ptr to delete JNI global references.
class GlobalRefDeleter {
public:
explicit GlobalRefDeleter(JavaVM* jvm) : jvm_(jvm) {}
GlobalRefDeleter(const GlobalRefDeleter& orig) = default;
// Copy assignment to allow move semantics in ScopedGlobalRef.
GlobalRefDeleter& operator=(const GlobalRefDeleter& rhs) {
TC3_CHECK_EQ(jvm_, rhs.jvm_);
return *this;
}
// The delete operator.
void operator()(jobject object) const {
JNIEnv* env;
if (object != nullptr && jvm_ != nullptr &&
JNI_OK ==
jvm_->GetEnv(reinterpret_cast<void**>(&env), JNI_VERSION_1_4)) {
env->DeleteGlobalRef(object);
}
}
private:
// The jvm_ stashed to use for deletion.
JavaVM* const jvm_;
};
// A deleter to be used with std::unique_ptr to delete JNI local references.
class LocalRefDeleter {
public:
explicit LocalRefDeleter(JNIEnv* env)
: env_(env) {} // NOLINT(runtime/explicit)
LocalRefDeleter(const LocalRefDeleter& orig) = default;
// Copy assignment to allow move semantics in ScopedLocalRef.
LocalRefDeleter& operator=(const LocalRefDeleter& rhs) {
env_ = rhs.env_;
return *this;
}
// The delete operator.
void operator()(jobject object) const {
if (env_) {
env_->DeleteLocalRef(object);
}
}
private:
// The env_ stashed to use for deletion. Thread-local, don't share!
JNIEnv* env_;
};
// A smart pointer that deletes a reference when it goes out of scope.
//
// Note that this class is not thread-safe since it caches JNIEnv in
// the deleter. Do not use the same jobject across different threads.
template <typename T, typename Env, typename Deleter>
class ScopedRef {
public:
ScopedRef() : ptr_(nullptr, Deleter(nullptr)) {}
ScopedRef(T value, Env* env) : ptr_(value, Deleter(env)) {}
T get() const { return ptr_.get(); }
T release() { return ptr_.release(); }
bool operator!() const { return !ptr_; }
bool operator==(void* value) const { return ptr_.get() == value; }
explicit operator bool() const { return ptr_ != nullptr; }
void reset(T value, Env* env) {
ptr_.reset(value);
ptr_.get_deleter() = Deleter(env);
}
private:
std::unique_ptr<typename std::remove_pointer<T>::type, Deleter> ptr_;
};
template <typename T, typename U, typename Env, typename Deleter>
inline bool operator==(const ScopedRef<T, Env, Deleter>& x,
const ScopedRef<U, Env, Deleter>& y) {
return x.get() == y.get();
}
template <typename T, typename Env, typename Deleter>
inline bool operator==(const ScopedRef<T, Env, Deleter>& x, std::nullptr_t) {
return x.get() == nullptr;
}
template <typename T, typename Env, typename Deleter>
inline bool operator==(std::nullptr_t, const ScopedRef<T, Env, Deleter>& x) {
return nullptr == x.get();
}
template <typename T, typename U, typename Env, typename Deleter>
inline bool operator!=(const ScopedRef<T, Env, Deleter>& x,
const ScopedRef<U, Env, Deleter>& y) {
return x.get() != y.get();
}
template <typename T, typename Env, typename Deleter>
inline bool operator!=(const ScopedRef<T, Env, Deleter>& x, std::nullptr_t) {
return x.get() != nullptr;
}
template <typename T, typename Env, typename Deleter>
inline bool operator!=(std::nullptr_t, const ScopedRef<T, Env, Deleter>& x) {
return nullptr != x.get();
}
template <typename T, typename U, typename Env, typename Deleter>
inline bool operator<(const ScopedRef<T, Env, Deleter>& x,
const ScopedRef<U, Env, Deleter>& y) {
return x.get() < y.get();
}
template <typename T, typename U, typename Env, typename Deleter>
inline bool operator>(const ScopedRef<T, Env, Deleter>& x,
const ScopedRef<U, Env, Deleter>& y) {
return x.get() > y.get();
}
// A smart pointer that deletes a JNI global reference when it goes out
// of scope. Usage is:
// ScopedGlobalRef<jobject> scoped_global(env->JniFunction(), jvm);
template <typename T>
using ScopedGlobalRef = ScopedRef<T, JavaVM, GlobalRefDeleter>;
// Ditto, but usage is:
// ScopedLocalRef<jobject> scoped_local(env->JniFunction(), env);
template <typename T>
using ScopedLocalRef = ScopedRef<T, JNIEnv, LocalRefDeleter>;
// A helper to create global references.
template <typename T>
ScopedGlobalRef<T> MakeGlobalRef(T object, JNIEnv* env, JavaVM* jvm) {
const jobject global_object = env->NewGlobalRef(object);
return ScopedGlobalRef<T>(reinterpret_cast<T>(global_object), jvm);
}
} // namespace libtextclassifier3
#endif // LIBTEXTCLASSIFIER_UTILS_JAVA_JNI_BASE_H_