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flipper/libs/fbjni/cxx/fbjni/detail/Exceptions.h
Pritesh Nandgaonkar 72045da4be Use the latest fbjni
2018-06-15 15:55:10 +01:00

141 lines
4.5 KiB
C++

/**
* Copyright 2018-present, Facebook, Inc.
*
* 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.
*/
/**
* @file Exceptions.h
*
* After invoking a JNI function that can throw a Java exception, the macro
* @ref FACEBOOK_JNI_THROW_PENDING_EXCEPTION() or @ref FACEBOOK_JNI_THROW_EXCEPTION_IF()
* should be invoked.
*
* IMPORTANT! IMPORTANT! IMPORTANT! IMPORTANT! IMPORTANT! IMPORTANT! IMPORTANT! IMPORTANT!
* To use these methods you MUST call initExceptionHelpers() when your library is loaded.
*/
#pragma once
#include <alloca.h>
#include <stdexcept>
#include <string>
#include <jni.h>
#include "Common.h"
#include "References.h"
#include "CoreClasses.h"
#if defined(__ANDROID__) && defined(__ARM_ARCH_5TE__) && !defined(FBJNI_NO_EXCEPTION_PTR)
// ARMv5 NDK does not support exception_ptr so we cannot use that when building for it.
#define FBJNI_NO_EXCEPTION_PTR
#endif
namespace facebook {
namespace jni {
class JThrowable;
class JCppException : public JavaClass<JCppException, JThrowable> {
public:
static auto constexpr kJavaDescriptor = "Lcom/facebook/jni/CppException;";
static local_ref<JCppException> create(const char* str) {
return newInstance(make_jstring(str));
}
static local_ref<JCppException> create(const std::exception& ex) {
return newInstance(make_jstring(ex.what()));
}
};
// JniException ////////////////////////////////////////////////////////////////////////////////////
/**
* This class wraps a Java exception into a C++ exception; if the exception is routed back
* to the Java side, it can be unwrapped and just look like a pure Java interaction. The class
* is resilient to errors while creating the exception, falling back to some pre-allocated
* exceptions if a new one cannot be allocated or populated.
*
* Note: the what() method of this class is not thread-safe (t6900503).
*/
class JniException : public std::exception {
public:
JniException();
~JniException();
explicit JniException(alias_ref<jthrowable> throwable);
JniException(JniException &&rhs);
JniException(const JniException &other);
local_ref<JThrowable> getThrowable() const noexcept;
virtual const char* what() const noexcept;
void setJavaException() const noexcept;
private:
global_ref<JThrowable> throwable_;
mutable std::string what_;
mutable bool isMessageExtracted_;
const static std::string kExceptionMessageFailure_;
void populateWhat() const noexcept;
};
// Exception throwing & translating functions //////////////////////////////////////////////////////
// Functions that throw C++ exceptions
static const int kMaxExceptionMessageBufferSize = 512;
// These methods are the preferred way to throw a Java exception from
// a C++ function. They create and throw a C++ exception which wraps
// a Java exception, so the C++ flow is interrupted. Then, when
// translatePendingCppExceptionToJavaException is called at the
// topmost level of the native stack, the wrapped Java exception is
// thrown to the java caller.
template<typename... Args>
[[noreturn]] void throwNewJavaException(const char* throwableName, const char* fmt, Args... args) {
int msgSize = snprintf(nullptr, 0, fmt, args...);
char *msg = (char*) alloca(msgSize + 1);
snprintf(msg, kMaxExceptionMessageBufferSize, fmt, args...);
throwNewJavaException(throwableName, msg);
}
// Identifies any pending C++ exception and throws it as a Java exception. If the exception can't
// be thrown, it aborts the program.
void translatePendingCppExceptionToJavaException();
#ifndef FBJNI_NO_EXCEPTION_PTR
local_ref<JThrowable> getJavaExceptionForCppException(std::exception_ptr ptr);
#endif
/***
* The stack returned may include build ids. It may be beneficial to
* call lyra::setLibraryIdentifierFunction before calling this if
* build ids are desirable.
*/
local_ref<JThrowable> getJavaExceptionForCppBackTrace();
local_ref<JThrowable> getJavaExceptionForCppBackTrace(const char* msg);
// For convenience, some exception names in java.lang are available here.
const char* const gJavaLangIllegalArgumentException = "java/lang/IllegalArgumentException";
}}