/*
 * Copyright (C) 2016-2023 Apple Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#pragma once

#include <wtf/Compiler.h>

WTF_ALLOW_UNSAFE_BUFFER_USAGE_BEGIN

#include <JavaScriptCore/VM.h>
#include <wtf/StackPointer.h>

WTF_ALLOW_UNSAFE_BUFFER_USAGE_END

namespace JSC {
    
class Exception;
    
#if ENABLE(EXCEPTION_SCOPE_VERIFICATION)

#define EXCEPTION_ASSERT(assertion) RELEASE_ASSERT(assertion)
#define EXCEPTION_ASSERT_UNUSED(variable, assertion) RELEASE_ASSERT(assertion)
#define EXCEPTION_ASSERT_WITH_MESSAGE(assertion, message) RELEASE_ASSERT_WITH_MESSAGE(assertion, message)

#if ENABLE(C_LOOP)
#define EXCEPTION_SCOPE_POSITION_FOR_ASAN(vm__) (vm__).currentCLoopStackPointer()
#elif ASAN_ENABLED
#define EXCEPTION_SCOPE_POSITION_FOR_ASAN(vm__) currentStackPointer()
#else
#define EXCEPTION_SCOPE_POSITION_FOR_ASAN(vm__) nullptr
#endif

class ExceptionScope {
public:
    VM& vm() const { return m_vm; }
    unsigned recursionDepth() const { return m_recursionDepth; }
    ALWAYS_INLINE Exception* exception() const { return m_vm.exception(); }

    ALWAYS_INLINE void assertNoException() { RELEASE_ASSERT_WITH_MESSAGE(!exception(), "%s", unexpectedExceptionMessage().data()); }
    ALWAYS_INLINE void releaseAssertNoException() { RELEASE_ASSERT_WITH_MESSAGE(!exception(), "%s", unexpectedExceptionMessage().data()); }
    ALWAYS_INLINE void assertNoExceptionExceptTermination() { RELEASE_ASSERT_WITH_MESSAGE(!exception() || m_vm.hasPendingTerminationException(), "%s", unexpectedExceptionMessage().data()); }
    ALWAYS_INLINE void releaseAssertNoExceptionExceptTermination() { RELEASE_ASSERT_WITH_MESSAGE(!exception() || m_vm.hasPendingTerminationException(), "%s", unexpectedExceptionMessage().data()); }

#if ASAN_ENABLED || ENABLE(C_LOOP)
    const void* stackPosition() const {  return m_location.stackPosition; }
#else
    const void* stackPosition() const {  return this; }
#endif

    [[nodiscard]] inline bool tryClearException();

protected:
    ExceptionScope(VM&, ExceptionEventLocation);
    ExceptionScope(const ExceptionScope&) = delete;
    ExceptionScope(ExceptionScope&&) = default;
    ~ExceptionScope();

    JS_EXPORT_PRIVATE CString unexpectedExceptionMessage();

    VM& m_vm;
    ExceptionScope* m_previousScope;
    ExceptionEventLocation m_location;
    unsigned m_recursionDepth;
};

#else // not ENABLE(EXCEPTION_SCOPE_VERIFICATION)
    
#define EXCEPTION_ASSERT(x) ASSERT(x)
#define EXCEPTION_ASSERT_UNUSED(variable, assertion) ASSERT_UNUSED(variable, assertion)
#define EXCEPTION_ASSERT_WITH_MESSAGE(assertion, message) ASSERT_WITH_MESSAGE(assertion, message)

class ExceptionScope {
public:
    ALWAYS_INLINE VM& vm() const { return m_vm; }
    ALWAYS_INLINE Exception* exception() const { return m_vm.exception(); }

    ALWAYS_INLINE void assertNoException() { ASSERT(!exception()); }
    ALWAYS_INLINE void releaseAssertNoException() { RELEASE_ASSERT(!exception()); }
    ALWAYS_INLINE void assertNoExceptionExceptTermination() { ASSERT(!exception() || m_vm.hasPendingTerminationException()); }
    ALWAYS_INLINE void releaseAssertNoExceptionExceptTermination() { RELEASE_ASSERT(!exception() || m_vm.hasPendingTerminationException()); }

    [[nodiscard]] ALWAYS_INLINE bool tryClearException();

protected:
    ALWAYS_INLINE ExceptionScope(VM& vm)
        : m_vm(vm)
    { }
    ExceptionScope(const ExceptionScope&) = delete;
    ExceptionScope(ExceptionScope&&) = default;

    ALWAYS_INLINE CString unexpectedExceptionMessage() { return { }; }

    VM& m_vm;
};

#endif // ENABLE(EXCEPTION_SCOPE_VERIFICATION)

bool ExceptionScope::tryClearException()
{
    SUPPRESS_FORWARD_DECL_ARG Exception* exception = this->exception();

    SUPPRESS_FORWARD_DECL_ARG if (exception && m_vm.isTerminationException(exception)) [[unlikely]]
        return false;

    m_vm.clearException();
    return true;
}

#define RETURN_IF_EXCEPTION(scope__, value__) do { \
        SUPPRESS_UNCOUNTED_LOCAL JSC::VM& vm = (scope__).vm(); \
        EXCEPTION_ASSERT(!!(scope__).exception() == vm.traps().needHandling(JSC::VMTraps::NeedExceptionHandling)); \
        if (vm.traps().maybeNeedHandling()) [[unlikely]] { \
            if (vm.hasExceptionsAfterHandlingTraps()) \
                return value__; \
        } \
    } while (false)


#define TRY_CLEAR_EXCEPTION(scope__, value__) do { \
        if (!(scope__).tryClearException()) [[unlikely]] \
            return value__; \
    } while (false)

#define RETURN_IF_EXCEPTION_WITH_TRAPS_DEFERRED(scope__, value__) do { \
        if ((scope__).exception()) [[unlikely]] \
            return value__; \
    } while (false)

#define RELEASE_AND_RETURN(scope__, expression__) do { \
        scope__.release(); \
        return expression__; \
    } while (false)

} // namespace JSC
