Logging.h

/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 2 -*-
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#ifndef MOZILLA_GFX_LOGGING_H_
#define MOZILLA_GFX_LOGGING_H_

#include <string>
#include <sstream>
#include <stdio.h>

#if defined(MOZ_WIDGET_GONK) || defined(MOZ_WIDGET_ANDROID)
#include "nsDebug.h"
#endif
#include "Point.h"
#include "BaseRect.h"
#include "Matrix.h"
#include "mozilla/TypedEnum.h"

#ifdef WIN32
// This file gets included from nsGlobalWindow.cpp, which doesn't like
// having windows.h included in it. Since OutputDebugStringA is the only
// thing we need from windows.h, we just declare it here directly.
// Note: the function's documented signature is
//  WINBASEAPI void WINAPI OutputDebugStringA(LPCSTR lpOutputString)
// but if we don't include windows.h, the macros WINBASEAPI, WINAPI, and 
// LPCSTR are not defined, so we need to replace them with their expansions.
extern "C" __declspec(dllimport) void __stdcall OutputDebugStringA(const char* lpOutputString);
#endif

#if defined(DEBUG) || defined(PR_LOGGING)
#include <prlog.h>

extern GFX2D_API PRLogModuleInfo *GetGFX2DLog();
#endif

namespace mozilla {
namespace gfx {

const int LOG_DEBUG = 1;
const int LOG_WARNING = 2;
const int LOG_CRITICAL = 3;

#if defined(DEBUG) || defined(PR_LOGGING)

inline PRLogModuleLevel PRLogLevelForLevel(int aLevel) {
  switch (aLevel) {
  case LOG_DEBUG:
    return PR_LOG_DEBUG;
  case LOG_WARNING:
    return PR_LOG_WARNING;
  }
  return PR_LOG_DEBUG;
}

#endif

extern GFX2D_API int sGfxLogLevel;

struct BasicLogger
{
  static void OutputMessage(const std::string &aString, int aLevel) {
#if defined(WIN32) && !defined(PR_LOGGING)
    if (aLevel >= sGfxLogLevel) {
      ::OutputDebugStringA(aString.c_str());
    }
#elif defined(PR_LOGGING) && !(defined(MOZ_WIDGET_GONK) || defined(MOZ_WIDGET_ANDROID))
    if (PR_LOG_TEST(GetGFX2DLog(), PRLogLevelForLevel(aLevel))) {
      PR_LogPrint(aString.c_str());
    }
#else
    if (aLevel >= sGfxLogLevel) {
#if defined(MOZ_WIDGET_GONK) || defined(MOZ_WIDGET_ANDROID)
      printf_stderr("%s", aString.c_str());
#else
      printf("%s", aString.c_str());
#endif
    }
#endif
  }
};

struct CriticalLogger {
  static void OutputMessage(const std::string &aString, int aLevel);
};

// Implement this interface and init the Factory with an instance to
// forward critical logs.
class LogForwarder {
public:
  virtual ~LogForwarder() {}
  virtual void Log(const std::string &aString) = 0;
};

class NoLog
{
public:
  NoLog() {}
  ~NoLog() {}

  template<typename T>
  NoLog &operator <<(const T &aLogText) { return *this; }
};

MOZ_BEGIN_ENUM_CLASS(LogOptions, int)
  NoNewline = 0x01
MOZ_END_ENUM_CLASS(LogOptions)

template<int L, typename Logger = BasicLogger>
class Log
{
public:
  explicit Log(LogOptions aOptions = LogOptions(0)) : mOptions(aOptions) {}
  ~Log() {
    Flush();
  }

  void Flush() {
    if (!(int(mOptions) & int(LogOptions::NoNewline))) {
      mMessage << '\n';
    }
    std::string str = mMessage.str();
    if (!str.empty()) {
      WriteLog(str);
    }
    mMessage.str("");
    mMessage.clear();
  }

  Log &operator <<(char aChar) { mMessage << aChar; return *this; }
  Log &operator <<(const std::string &aLogText) { mMessage << aLogText; return *this; }
  Log &operator <<(const char aStr[]) { mMessage << static_cast<const char*>(aStr); return *this; }
  Log &operator <<(bool aBool) { mMessage << (aBool ? "true" : "false"); return *this; }
  Log &operator <<(int aInt) { mMessage << aInt; return *this; }
  Log &operator <<(unsigned int aInt) { mMessage << aInt; return *this; }
  Log &operator <<(long aLong) { mMessage << aLong; return *this; }
  Log &operator <<(unsigned long aLong) { mMessage << aLong; return *this; }
  Log &operator <<(long long aLong) { mMessage << aLong; return *this; }
  Log &operator <<(unsigned long long aLong) { mMessage << aLong; return *this; }
  Log &operator <<(Float aFloat) { mMessage << aFloat; return *this; }
  Log &operator <<(double aDouble) { mMessage << aDouble; return *this; }
  template <typename T, typename Sub>
  Log &operator <<(const BasePoint<T, Sub>& aPoint)
    { mMessage << "Point" << aPoint; return *this; }
  template <typename T, typename Sub>
  Log &operator <<(const BaseSize<T, Sub>& aSize)
    { mMessage << "Size(" << aSize.width << "," << aSize.height << ")"; return *this; }
  template <typename T, typename Sub, typename Point, typename SizeT, typename Margin>
  Log &operator <<(const BaseRect<T, Sub, Point, SizeT, Margin>& aRect)
    { mMessage << "Rect" << aRect; return *this; }
  Log &operator<<(const Matrix& aMatrix)
    { mMessage << "Matrix(" << aMatrix._11 << " " << aMatrix._12 << " ; " << aMatrix._21 << " " << aMatrix._22 << " ; " << aMatrix._31 << " " << aMatrix._32 << ")"; return *this; }


private:

  void WriteLog(const std::string &aString) {
    Logger::OutputMessage(aString, L);
  }

  std::stringstream mMessage;
  LogOptions mOptions;
};

typedef Log<LOG_DEBUG> DebugLog;
typedef Log<LOG_WARNING> WarningLog;
typedef Log<LOG_CRITICAL, CriticalLogger> CriticalLog;

#ifdef GFX_LOG_DEBUG
#define gfxDebug DebugLog
#else
#define gfxDebug if (1) ; else NoLog
#endif
#ifdef GFX_LOG_WARNING
#define gfxWarning WarningLog
#else
#define gfxWarning if (1) ; else NoLog
#endif

// This log goes into crash reports, use with care.
#define gfxCriticalError CriticalLog

// See nsDebug.h and the NS_WARN_IF macro

#ifdef __cplusplus
#ifdef DEBUG
inline bool MOZ2D_warn_if_impl(bool aCondition, const char* aExpr,
                               const char* aFile, int32_t aLine)
{
  if (MOZ_UNLIKELY(aCondition)) {
    gfxWarning() << aExpr << " at " << aFile << ":" << aLine;
  }
  return aCondition;
}
#define MOZ2D_WARN_IF(condition) \
  MOZ2D_warn_if_impl(condition, #condition, __FILE__, __LINE__)
#else
#define MOZ2D_WARN_IF(condition) (bool)(condition)
#endif
#endif

const int INDENT_PER_LEVEL = 2;

class TreeLog
{
public:
  explicit TreeLog(const std::string& aPrefix = "")
        : mLog(LogOptions::NoNewline),
          mPrefix(aPrefix),
          mDepth(0),
          mStartOfLine(true),
          mConditionedOnPref(false),
          mPrefFunction(nullptr) {}

  template <typename T>
  TreeLog& operator<<(const T& aObject) {
    if (mConditionedOnPref && !mPrefFunction()) {
      return *this;
    }
    if (mStartOfLine) {
      mLog << '[' << mPrefix << "] " << std::string(mDepth * INDENT_PER_LEVEL, ' ');
      mStartOfLine = false;
    }
    mLog << aObject;
    if (EndsInNewline(aObject)) {
      // Don't indent right here as the user may change the indent
      // between now and the first output to the next line.
      mLog.Flush();
      mStartOfLine = true;
    }
    return *this;
  }

  void IncreaseIndent() { ++mDepth; }
  void DecreaseIndent() { --mDepth; }

  void ConditionOnPrefFunction(bool(*aPrefFunction)()) {
    mConditionedOnPref = true;
    mPrefFunction = aPrefFunction;
  }
private:
  Log<LOG_DEBUG> mLog;
  std::string mPrefix;
  uint32_t mDepth;
  bool mStartOfLine;
  bool mConditionedOnPref;
  bool (*mPrefFunction)();

  template <typename T>
  static bool EndsInNewline(const T& aObject) {
    return false;
  }

  static bool EndsInNewline(const std::string& aString) {
    return !aString.empty() && aString[aString.length() - 1] == '\n';
  }

  static bool EndsInNewline(char aChar) {
    return aChar == '\n';
  }

  static bool EndsInNewline(const char* aString) {
    return EndsInNewline(std::string(aString));
  }
};

class TreeAutoIndent
{
public:
  explicit TreeAutoIndent(TreeLog& aTreeLog) : mTreeLog(aTreeLog) {
    mTreeLog.IncreaseIndent();
  }
  ~TreeAutoIndent() {
    mTreeLog.DecreaseIndent();
  }
private:
  TreeLog& mTreeLog;
};

}
}

#endif /* MOZILLA_GFX_LOGGING_H_ */