capture.h

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// Copyright (c) Microsoft Corporation. All rights reserved.
// Licensed under the MIT License.

#pragma once

#include <cstdarg>
#include "core/common/gsl.h"
#include "core/common/common.h"
#include "core/common/code_location.h"
#include "core/common/logging/severity.h"

namespace onnxruntime {
namespace logging {

class Logger;
enum class DataType;

/**
   Class to capture the details of a log message.
*/
class Capture {
 public:
  /**
     Initializes a new instance of the Capture class.
     @param logger The logger.
     @param severity The severity.
     @param category The category.
     @param dataType Type of the data.
     @param location The file location the log message is coming from.
  */
  Capture(const Logger& logger, logging::Severity severity, const char* category,
          logging::DataType dataType, const CodeLocation& location)
      : logger_{&logger}, severity_{severity}, category_{category}, data_type_{dataType}, location_{location} {
  }

  /**
     The stream that can capture the message via operator<<.
     @returns Output stream.
  */
  std::ostream& Stream() noexcept {
    return stream_;
  }

#ifdef _MSC_VER
// add SAL annotation for printf format string. requires Code Analysis to run to validate usage.
#define msvc_printf_check _Printf_format_string_
#define __attribute__(x)  // Disable for MSVC. Supported by GCC and CLang.
#else
#define msvc_printf_check
#endif

  /**
     Captures a printf style log message.
     @param name="format">The printf format.
     @param name="">Arguments to the printf format if needed.
     @remarks
     A maximum of 2K of output will be captured currently.
     Non-static method, so 'this' is implicit first arg, and we use format(printf(2,3)
  */
  void CapturePrintf(msvc_printf_check const char* format, ...) __attribute__((format(printf, 2, 3)));

  /**
     Process a printf style log message.
     @param format The printf format.
     @param ... Arguments to the printf format if needed.
     @remarks
     A maximum of 2K of output will be captured currently.
     Note: As va_list is 'char *', we have to disambiguate this from CapturePrintf
     so that something like "One string: %s", "the string" does not consider "the string"
     to be the va_list.
  */
  void ProcessPrintf(msvc_printf_check const char* format, va_list args);

  logging::Severity Severity() const noexcept {
    return severity_;
  }

  char SeverityPrefix() const noexcept {
    // Carefully setup so severity_ is a valid index
    GSL_SUPPRESS(bounds .2) {
      return logging::SEVERITY_PREFIX[static_cast<int>(severity_)];
    }
  }

  const char* Category() const noexcept {
    return category_;
  }

  logging::DataType DataType() const noexcept {
    return data_type_;
  }

  const CodeLocation& Location() const noexcept {
    return location_;
  }

  std::string Message() const noexcept {
    return stream_.str();
  }

  ~Capture();

 private:
  ORT_DISALLOW_COPY_ASSIGNMENT_AND_MOVE(Capture);

  const Logger* logger_;
  const logging::Severity severity_;
  const char* category_;
  const logging::DataType data_type_;
  const CodeLocation location_;

  std::ostringstream stream_;
};
}  // namespace logging
}  // namespace onnxruntime