arangodb/lib/Basics/Exceptions.cpp

////////////////////////////////////////////////////////////////////////////////
/// DISCLAIMER
///
/// Copyright 2014-2016 ArangoDB GmbH, Cologne, Germany
/// Copyright 2004-2014 triAGENS GmbH, Cologne, Germany
///
/// 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.
///
/// Copyright holder is ArangoDB GmbH, Cologne, Germany
///
/// @author Dr. Frank Celler
////////////////////////////////////////////////////////////////////////////////

#include "Exceptions.h"
#include "Logger/Logger.h"

#include <cstdarg>

#ifdef ARANGODB_ENABLE_MAINTAINER_MODE
#include <cstring>
#endif

using namespace arangodb;
using namespace arangodb::basics;

/// @brief controls if backtraces are printed with exceptions
static bool WithBackTrace = false;

/// @brief controls whether a backtrace is created for each exception
void Exception::SetVerbose(bool verbose) { WithBackTrace = verbose; }

/// @brief constructor, without format string
Exception::Exception(int code, char const* file, int line)
    : _errorMessage(TRI_errno_string(code)), _file(file), _line(line), _code(code) {
  appendLocation();
}

Exception::Exception(arangodb::Result const& result, char const* file, int line)
    : _errorMessage(result.errorMessage()),
      _file(file),
      _line(line),
      _code(result.errorNumber()) {
  appendLocation();
}

Exception::Exception(arangodb::Result&& result, char const* file, int line)
    : _errorMessage(std::move(result).errorMessage()),  // cast to rvalueref so the error
                                                        // string gets moved out
      _file(file),
      _line(line),
      _code(result.errorNumber()) {
  appendLocation();
}

/// @brief constructor, for creating an exception with an already created
/// error message (normally based on error templates containing %s, %d etc.)
Exception::Exception(int code, std::string const& errorMessage, char const* file, int line)
    : _errorMessage(errorMessage), _file(file), _line(line), _code(code) {
  appendLocation();
}

/// @brief constructor, for creating an exception with an already created
/// error message (normally based on error templates containing %s, %d etc.)
Exception::Exception(int code, std::string&& errorMessage, char const* file, int line)
    : _errorMessage(std::move(errorMessage)), _file(file), _line(line), _code(code) {
  appendLocation();
}

/// @brief constructor, for creating an exception with an already created
/// error message (normally based on error templates containing %s, %d etc.)
Exception::Exception(int code, char const* errorMessage, char const* file, int line)
    : _errorMessage(errorMessage), _file(file), _line(line), _code(code) {
  appendLocation();
}

Exception::~Exception() {}

/// @brief returns the error message
std::string const& Exception::message() const noexcept { return _errorMessage; }

/// @brief returns the error code
int Exception::code() const noexcept { return _code; }

/// @brief adds to the message
void Exception::addToMessage(std::string const& more) { _errorMessage += more; }

/// @brief return exception message
char const* Exception::what() const noexcept { return _errorMessage.c_str(); }

/// @brief append original error location to message
void Exception::appendLocation() noexcept {
  try {
    if (_code == TRI_ERROR_INTERNAL) {
      _errorMessage += std::string(" (exception location: ") + _file + ":" +
                       std::to_string(_line) +
                       "). Please report this error to arangodb.com";
    } else if (_code == TRI_ERROR_OUT_OF_MEMORY || _code == TRI_ERROR_NOT_IMPLEMENTED) {
      _errorMessage += std::string(" (exception location: ") + _file + ":" +
                       std::to_string(_line) + ")";
    }

#ifdef ARANGODB_ENABLE_MAINTAINER_MODE
#if ARANGODB_ENABLE_BACKTRACE
    if (WithBackTrace) {
      _errorMessage += std::string("\n\n");
      TRI_GetBacktrace(_errorMessage);
      _errorMessage += std::string("\n\n");
    }
#endif
#endif
  } catch (...) {
    // this function is called from the exception constructor, so it should
    // not itself throw another exception
  }
}

/// @brief construct an error message from a template string
std::string Exception::FillExceptionString(int code, ...) {
  char const* format = TRI_errno_string(code);
  TRI_ASSERT(format != nullptr);

#ifdef ARANGODB_ENABLE_MAINTAINER_MODE
  // Obviously the formatstring of the error code has to support parameters.
  TRI_ASSERT(strchr(format, '%') != nullptr);
#endif

  char buffer[1024];
  va_list ap;
  va_start(ap, code);
  int length = vsnprintf(buffer, sizeof(buffer) - 1, format, ap);
  va_end(ap);
  buffer[sizeof(buffer) - 1] = '\0';  // Windows

  if (length < 0) {
    // error in vsnprintf
    return std::string(format);
  }

  return std::string(buffer, size_t(length));
}

/// @brief construct an error message from a template string
std::string Exception::FillFormatExceptionString(char const* format, ...) {
  TRI_ASSERT(format != nullptr);

#ifdef ARANGODB_ENABLE_MAINTAINER_MODE
  // Format #1 should come from the macro...
  TRI_ASSERT(strchr(format, '%') != nullptr);
  // Obviously the user has to give us a format string.
  TRI_ASSERT(strchr(strchr(format, '%'), '%') != nullptr);
#endif

  char buffer[1024];
  va_list ap;
  va_start(ap, format);
  int length = vsnprintf(buffer, sizeof(buffer) - 1, format, ap);
  va_end(ap);
  buffer[sizeof(buffer) - 1] = '\0';  // Windows

  if (length < 0) {
    // error in vsnprintf
    return std::string(format);
  }

  return std::string(buffer, size_t(length));
}