// Copyright (c) 2013-2014 Sandstorm Development Group, Inc. and contributors
// Licensed under the MIT License:
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.

#include "exception.h"
#include "debug.h"
#include <kj/compat/gtest.h>
#include <stdexcept>

namespace kj {
namespace _ {  // private
namespace {

TEST(Exception, TrimSourceFilename) {
#if _WIN32
  EXPECT_TRUE(trimSourceFilename(__FILE__) == "kj/exception-test.c++" ||
              trimSourceFilename(__FILE__) == "kj\\exception-test.c++");
#else
  EXPECT_EQ(trimSourceFilename(__FILE__), "kj/exception-test.c++");
#endif
}

TEST(Exception, RunCatchingExceptions) {
  bool recovered = false;
  Maybe<Exception> e = kj::runCatchingExceptions([&]() {
    KJ_FAIL_ASSERT("foo") {
      break;
    }
    recovered = true;
  });

#if KJ_NO_EXCEPTIONS
  EXPECT_TRUE(recovered);
#else
  EXPECT_FALSE(recovered);
#endif

  KJ_IF_MAYBE(ex, e) {
    EXPECT_EQ("foo", ex->getDescription());
  } else {
    ADD_FAILURE() << "Expected exception";
  }
}

#if !KJ_NO_EXCEPTIONS
TEST(Exception, RunCatchingExceptionsStdException) {
  Maybe<Exception> e = kj::runCatchingExceptions([&]() {
    throw std::logic_error("foo");
  });

  KJ_IF_MAYBE(ex, e) {
    EXPECT_EQ("std::exception: foo", ex->getDescription());
  } else {
    ADD_FAILURE() << "Expected exception";
  }
}

TEST(Exception, RunCatchingExceptionsOtherException) {
  Maybe<Exception> e = kj::runCatchingExceptions([&]() {
    throw 123;
  });

  KJ_IF_MAYBE(ex, e) {
#if __GNUC__ && !KJ_NO_RTTI
    EXPECT_EQ("unknown non-KJ exception of type: int", ex->getDescription());
#else
    EXPECT_EQ("unknown non-KJ exception", ex->getDescription());
#endif
  } else {
    ADD_FAILURE() << "Expected exception";
  }
}
#endif

#if !KJ_NO_EXCEPTIONS
// We skip this test when exceptions are disabled because making it no-exceptions-safe defeats
// the purpose of the test: recoverable exceptions won't throw inside a destructor in the first
// place.

class ThrowingDestructor: public UnwindDetector {
public:
  ~ThrowingDestructor() noexcept(false) {
    catchExceptionsIfUnwinding([]() {
      KJ_FAIL_ASSERT("this is a test, not a real bug");
    });
  }
};

TEST(Exception, UnwindDetector) {
  // If no other exception is happening, ThrowingDestructor's destructor throws one.
  Maybe<Exception> e = kj::runCatchingExceptions([&]() {
    ThrowingDestructor t;
  });

  KJ_IF_MAYBE(ex, e) {
    EXPECT_EQ("this is a test, not a real bug", ex->getDescription());
  } else {
    ADD_FAILURE() << "Expected exception";
  }

  // If another exception is happening, ThrowingDestructor's destructor's exception is squelched.
  e = kj::runCatchingExceptions([&]() {
    ThrowingDestructor t;
    KJ_FAIL_ASSERT("baz") {
      break;
    }
  });

  KJ_IF_MAYBE(ex, e) {
    EXPECT_EQ("baz", ex->getDescription());
  } else {
    ADD_FAILURE() << "Expected exception";
  }
}
#endif

#if !__MINGW32__  // Inexplicably crashes when exception is thrown from constructor.
TEST(Exception, ExceptionCallbackMustBeOnStack) {
  KJ_EXPECT_THROW_MESSAGE("must be allocated on the stack", new ExceptionCallback);
}
#endif  // !__MINGW32__

#if !KJ_NO_EXCEPTIONS
TEST(Exception, ScopeSuccessFail) {
  bool success = false;
  bool failure = false;

  {
    KJ_ON_SCOPE_SUCCESS(success = true);
    KJ_ON_SCOPE_FAILURE(failure = true);

    EXPECT_FALSE(success);
    EXPECT_FALSE(failure);
  }

  EXPECT_TRUE(success);
  EXPECT_FALSE(failure);

  success = false;
  failure = false;

  try {
    KJ_ON_SCOPE_SUCCESS(success = true);
    KJ_ON_SCOPE_FAILURE(failure = true);

    EXPECT_FALSE(success);
    EXPECT_FALSE(failure);

    throw 1;
  } catch (int) {}

  EXPECT_FALSE(success);
  EXPECT_TRUE(failure);
}
#endif

#if __GNUG__
kj::String testStackTrace() __attribute__((noinline));
#elif _MSC_VER
__declspec(noinline) kj::String testStackTrace();
#endif

kj::String testStackTrace() {
  // getStackTrace() normally skips its immediate caller, so we wrap it in another layer.
  return getStackTrace();
}

KJ_TEST("getStackTrace() returns correct line number, not line + 1") {
  // Backtraces normally produce the return address of each stack frame, but that's usually the
  // address immediately after the one that made the call. As a result, it used to be that stack
  // traces often pointed to the line after the one that made a call, which was confusing. This
  // checks that this bug is fixed.
  //
  // This is not a very robust test, because:
  // 1) Since symbolic stack traces are not available in many situations (e.g. release builds
  //    lacking debug symbols, systems where addr2line isn't present, etc.), we only check that
  //    the stack trace does *not* contain the *wrong* value, rather than checking that it does
  //    contain the right one.
  // 2) This test only detects the problem if the call instruction to testStackTrace() is the
  //    *last* instruction attributed to its line of code. Whether or not this is true seems to be
  //    dependent on obscure complier behavior. For example, below, it could only be the case if
  //    RVO is applied -- but in my testing, RVO does seem to be applied here. I tried several
  //    variations involving passing via an output parameter or a global variable rather than
  //    returning, but found some variations detected the problem and others didn't, essentially
  //    at random.

  auto trace = testStackTrace();
  auto wrong = kj::str("exception-test.c++:", __LINE__);

  KJ_ASSERT(strstr(trace.cStr(), wrong.cStr()) == nullptr, trace, wrong);
}

}  // namespace
}  // namespace _ (private)
}  // namespace kj
