path: root/gfx/2d/Logging.h

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* 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>
#include <vector>

#ifdef MOZ_LOGGING
#  include "mozilla/Logging.h"
#endif

#if defined(MOZ_WIDGET_ANDROID)
#  include "nsDebug.h"
#endif
#include "2D.h"
#include "mozilla/Atomics.h"
#include "mozilla/StaticPrefs_gfx.h"
#include "Point.h"
#include "BaseRect.h"
#include "Matrix.h"
#include "LoggingConstants.h"

#if defined(MOZ_LOGGING)
extern GFX2D_API mozilla::LogModule* GetGFX2DLog();
#endif

namespace mozilla {
namespace gfx {

#if defined(MOZ_LOGGING)
inline mozilla::LogLevel PRLogLevelForLevel(int aLevel) {
  switch (aLevel) {
    case LOG_CRITICAL:
      return LogLevel::Error;
    case LOG_WARNING:
      return LogLevel::Warning;
    case LOG_DEBUG:
      return LogLevel::Debug;
    case LOG_DEBUG_PRLOG:
      return LogLevel::Debug;
    case LOG_EVERYTHING:
      return LogLevel::Error;
  }
  return LogLevel::Debug;
}
#endif

/// Graphics logging is available in both debug and release builds and is
/// controlled with a gfx.logging.level preference. If not set, the default
/// for the preference is 5 in the debug builds, 1 in the release builds.
///
/// gfxDebug only works in the debug builds, and is used for information
/// level messages, helping with debugging.  In addition to only working
/// in the debug builds, the value of the above preference of 3 or higher
/// is required.
///
/// gfxWarning messages are available in both debug and release builds,
/// on by default in the debug builds, and off by default in the release builds.
/// Setting the preference gfx.logging.level to a value of 2 or higher will
/// show the warnings.
///
/// gfxCriticalError is available in debug and release builds by default.
/// It is only unavailable if gfx.logging.level is set to 0 (or less.)
/// It outputs the message to stderr or equivalent, like gfxWarning.
/// In the event of a crash, the crash report is annotated with first and
/// the last few of these errors, under the key GraphicsCriticalError.
/// The total number of errors stored in the crash report is controlled
/// by preference gfx.logging.crash.length.
///
/// On platforms that support MOZ_LOGGING, the story is slightly more involved.
/// In that case, unless gfx.logging.level is set to 4 or higher, the output
/// is further controlled by the "gfx2d" logging module.  However, in the case
/// where such module would disable the output, in all but gfxDebug cases,
/// we will still send a printf.

// The range is due to the values set in Histograms.json
enum class LogReason : int {
  MustBeMoreThanThis = -1,
  // Start.  Do not insert, always add at end.  If you remove items,
  // make sure the other items retain their values.
  D3D11InvalidCallDeviceRemoved = 0,
  D3D11InvalidCall,
  D3DLockTimeout,
  D3D10FinalizeFrame,
  D3D11FinalizeFrame,
  D3D10SyncLock,
  D3D11SyncLock,
  D2D1NoWriteMap,
  JobStatusError,
  FilterInputError,
  FilterInputData,  // 10
  FilterInputRect,
  FilterInputSet,
  FilterInputFormat,
  FilterNodeD2D1Target,
  FilterNodeD2D1Backend,
  SourceSurfaceIncompatible,
  GlyphAllocFailedCairo,
  GlyphAllocFailedCG,
  InvalidRect,
  CannotDraw3D,  // 20
  IncompatibleBasicTexturedEffect,
  InvalidFont,
  PAllocTextureBackendMismatch,
  GetFontFileDataFailed,
  MessageChannelCloseFailure,
  MessageChannelInvalidHandle,
  TextureAliveAfterShutdown,
  InvalidContext,
  InvalidCommandList,
  AsyncTransactionTimeout,  // 30
  TextureCreation,
  InvalidCacheSurface,
  AlphaWithBasicClient,
  UnbalancedClipStack,
  ProcessingError,
  InvalidDrawTarget,
  NativeFontResourceNotFound,
  UnscaledFontNotFound,
  ScaledFontNotFound,
  InvalidLayerType,  // 40
  // End
  MustBeLessThanThis = 101,
};

struct BasicLogger {
  // For efficiency, this method exists and copies the logic of the
  // OutputMessage below.  If making any changes here, also make it
  // in the appropriate places in that method.
  static bool ShouldOutputMessage(int aLevel) {
    if (StaticPrefs::gfx_logging_level() >= aLevel) {
#if defined(MOZ_WIDGET_ANDROID)
      return true;
#else
#  if defined(MOZ_LOGGING)
      if (MOZ_LOG_TEST(GetGFX2DLog(), PRLogLevelForLevel(aLevel))) {
        return true;
      } else
#  endif
          if ((StaticPrefs::gfx_logging_level() >= LOG_DEBUG_PRLOG) ||
              (aLevel < LOG_DEBUG)) {
        return true;
      }
#endif
    }
    return false;
  }

  // Only for really critical errors.
  static void CrashAction(LogReason aReason) {}

  static void OutputMessage(const std::string& aString, int aLevel,
                            bool aNoNewline) {
    // This behavior (the higher the preference, the more we log)
    // is consistent with what prlog does in general.  Note that if prlog
    // is in the build, but disabled, we will printf if the preferences
    // requires us to log something.
    //
    // If making any logic changes to this method, you should probably
    // make the corresponding change in the ShouldOutputMessage method
    // above.
    if (StaticPrefs::gfx_logging_level() >= aLevel) {
#if defined(MOZ_WIDGET_ANDROID)
      printf_stderr("%s%s", aString.c_str(), aNoNewline ? "" : "\n");
#else
#  if defined(MOZ_LOGGING)
      if (MOZ_LOG_TEST(GetGFX2DLog(), PRLogLevelForLevel(aLevel))) {
        MOZ_LOG(GetGFX2DLog(), PRLogLevelForLevel(aLevel),
                ("%s%s", aString.c_str(), aNoNewline ? "" : "\n"));
      } else
#  endif
          if ((StaticPrefs::gfx_logging_level() >= LOG_DEBUG_PRLOG) ||
              (aLevel < LOG_DEBUG)) {
        printf("%s%s", aString.c_str(), aNoNewline ? "" : "\n");
      }
#endif
    }
  }
};

struct CriticalLogger {
  static void OutputMessage(const std::string& aString, int aLevel,
                            bool aNoNewline);
  static void CrashAction(LogReason aReason);
};

// The int is the index of the Log call; if the number of logs exceeds some
// preset capacity we may not get all of them, so the indices help figure out
// which ones we did save.  The double is expected to be the "TimeDuration",
// time in seconds since the process creation.
typedef std::tuple<int32_t, std::string, double> LoggingRecordEntry;

// Implement this interface and init the Factory with an instance to
// forward critical logs.
typedef std::vector<LoggingRecordEntry> LoggingRecord;
class LogForwarder {
 public:
  virtual ~LogForwarder() = default;
  virtual void Log(const std::string& aString) = 0;
  virtual void CrashAction(LogReason aReason) = 0;
  virtual bool UpdateStringsVector(const std::string& aString) = 0;

  // Provide a copy of the logs to the caller.
  virtual LoggingRecord LoggingRecordCopy() = 0;
};

class NoLog {
 public:
  NoLog() = default;
  ~NoLog() = default;

  // No-op
  MOZ_IMPLICIT NoLog(const NoLog&) = default;

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

enum class LogOptions : int {
  NoNewline = 0x01,
  AutoPrefix = 0x02,
  AssertOnCall = 0x04,
  CrashAction = 0x08,
};

template <typename T>
struct Hexa {
  explicit Hexa(T aVal) : mVal(aVal) {}
  T mVal;
};
template <typename T>
Hexa<T> hexa(T val) {
  return Hexa<T>(val);
}

#ifdef WIN32
void LogWStr(const wchar_t* aStr, std::stringstream& aOut);
#endif

template <int L, typename Logger = BasicLogger>
class Log final {
 public:
  // The default is to have the prefix, have the new line, and for critical
  // logs assert on each call.
  static int DefaultOptions(bool aWithAssert = true) {
    return (int(LogOptions::AutoPrefix) |
            (aWithAssert ? int(LogOptions::AssertOnCall) : 0));
  }

  // Note that we're calling BasicLogger::ShouldOutputMessage, rather than
  // Logger::ShouldOutputMessage.  Since we currently don't have a different
  // version of that method for different loggers, this is OK. Once we do,
  // change BasicLogger::ShouldOutputMessage to Logger::ShouldOutputMessage.
  explicit Log(int aOptions = Log::DefaultOptions(L == LOG_CRITICAL),
               LogReason aReason = LogReason::MustBeMoreThanThis)
      : mOptions(0), mLogIt(false) {
    Init(aOptions, BasicLogger::ShouldOutputMessage(L), aReason);
  }

  ~Log() { Flush(); }

  void Flush() {
    if (MOZ_LIKELY(!LogIt())) return;

    std::string str = mMessage.str();
    if (!str.empty()) {
      WriteLog(str);
    }
    mMessage.str("");
  }

  Log& operator<<(char aChar) {
    if (MOZ_UNLIKELY(LogIt())) {
      mMessage << aChar;
    }
    return *this;
  }
  Log& operator<<(const std::string& aLogText) {
    if (MOZ_UNLIKELY(LogIt())) {
      mMessage << aLogText;
    }
    return *this;
  }
  Log& operator<<(const char aStr[]) {
    if (MOZ_UNLIKELY(LogIt())) {
      mMessage << static_cast<const char*>(aStr);
    }
    return *this;
  }
#ifdef WIN32
  Log& operator<<(const wchar_t aWStr[]) {
    if (MOZ_UNLIKELY(LogIt())) {
      LogWStr(aWStr, mMessage);
    }
    return *this;
  }
#endif
  Log& operator<<(bool aBool) {
    if (MOZ_UNLIKELY(LogIt())) {
      mMessage << (aBool ? "true" : "false");
    }
    return *this;
  }
  Log& operator<<(int aInt) {
    if (MOZ_UNLIKELY(LogIt())) {
      mMessage << aInt;
    }
    return *this;
  }
  Log& operator<<(unsigned int aInt) {
    if (MOZ_UNLIKELY(LogIt())) {
      mMessage << aInt;
    }
    return *this;
  }
  Log& operator<<(long aLong) {
    if (MOZ_UNLIKELY(LogIt())) {
      mMessage << aLong;
    }
    return *this;
  }
  Log& operator<<(unsigned long aLong) {
    if (MOZ_UNLIKELY(LogIt())) {
      mMessage << aLong;
    }
    return *this;
  }
  Log& operator<<(long long aLong) {
    if (MOZ_UNLIKELY(LogIt())) {
      mMessage << aLong;
    }
    return *this;
  }
  Log& operator<<(unsigned long long aLong) {
    if (MOZ_UNLIKELY(LogIt())) {
      mMessage << aLong;
    }
    return *this;
  }
  Log& operator<<(Float aFloat) {
    if (MOZ_UNLIKELY(LogIt())) {
      mMessage << aFloat;
    }
    return *this;
  }
  Log& operator<<(double aDouble) {
    if (MOZ_UNLIKELY(LogIt())) {
      mMessage << aDouble;
    }
    return *this;
  }
  Log& operator<<(const sRGBColor& aColor) {
    if (MOZ_UNLIKELY(LogIt())) {
      mMessage << "sRGBColor(" << aColor.r << ", " << aColor.g << ", "
               << aColor.b << ", " << aColor.a << ")";
    }
    return *this;
  }
  Log& operator<<(const DeviceColor& aColor) {
    if (MOZ_UNLIKELY(LogIt())) {
      mMessage << "DeviceColor(" << aColor.r << ", " << aColor.g << ", "
               << aColor.b << ", " << aColor.a << ")";
    }
    return *this;
  }
  template <typename T, typename Sub, typename Coord>
  Log& operator<<(const BasePoint<T, Sub, Coord>& aPoint) {
    if (MOZ_UNLIKELY(LogIt())) {
      mMessage << "Point" << aPoint;
    }
    return *this;
  }
  template <typename T, typename Sub>
  Log& operator<<(const BaseSize<T, Sub>& aSize) {
    if (MOZ_UNLIKELY(LogIt())) {
      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) {
    if (MOZ_UNLIKELY(LogIt())) {
      mMessage << "Rect" << aRect;
    }
    return *this;
  }
  Log& operator<<(const Matrix& aMatrix) {
    if (MOZ_UNLIKELY(LogIt())) {
      mMessage << "Matrix(" << aMatrix._11 << " " << aMatrix._12 << " ; "
               << aMatrix._21 << " " << aMatrix._22 << " ; " << aMatrix._31
               << " " << aMatrix._32 << ")";
    }
    return *this;
  }
  template <typename T>
  Log& operator<<(Hexa<T> aHex) {
    if (MOZ_UNLIKELY(LogIt())) {
      mMessage << std::showbase << std::hex << aHex.mVal << std::noshowbase
               << std::dec;
    }
    return *this;
  }

  Log& operator<<(const SourceSurface* aSurface) {
    if (MOZ_UNLIKELY(LogIt())) {
      mMessage << "SourceSurface(" << (void*)(aSurface) << ")";
    }
    return *this;
  }
  Log& operator<<(const Path* aPath) {
    if (MOZ_UNLIKELY(LogIt())) {
      mMessage << "Path(" << (void*)(aPath) << ")";
    }
    return *this;
  }
  Log& operator<<(const Pattern* aPattern) {
    if (MOZ_UNLIKELY(LogIt())) {
      mMessage << "Pattern(" << (void*)(aPattern) << ")";
    }
    return *this;
  }
  Log& operator<<(const ScaledFont* aFont) {
    if (MOZ_UNLIKELY(LogIt())) {
      mMessage << "ScaledFont(" << (void*)(aFont) << ")";
    }
    return *this;
  }
  Log& operator<<(const FilterNode* aFilter) {
    if (MOZ_UNLIKELY(LogIt())) {
      mMessage << "FilterNode(" << (void*)(aFilter) << ")";
    }
    return *this;
  }
  Log& operator<<(const DrawOptions& aOptions) {
    if (MOZ_UNLIKELY(LogIt())) {
      mMessage << "DrawOptions(" << aOptions.mAlpha << ", ";
      (*this) << aOptions.mCompositionOp;
      mMessage << ", ";
      (*this) << aOptions.mAntialiasMode;
      mMessage << ")";
    }
    return *this;
  }
  Log& operator<<(const DrawSurfaceOptions& aOptions) {
    if (MOZ_UNLIKELY(LogIt())) {
      mMessage << "DrawSurfaceOptions(";
      (*this) << aOptions.mSamplingFilter;
      mMessage << ", ";
      (*this) << aOptions.mSamplingBounds;
      mMessage << ")";
    }
    return *this;
  }

  Log& operator<<(SamplingBounds aBounds) {
    if (MOZ_UNLIKELY(LogIt())) {
      switch (aBounds) {
        case SamplingBounds::UNBOUNDED:
          mMessage << "SamplingBounds::UNBOUNDED";
          break;
        case SamplingBounds::BOUNDED:
          mMessage << "SamplingBounds::BOUNDED";
          break;
        default:
          mMessage << "Invalid SamplingBounds (" << (int)aBounds << ")";
          break;
      }
    }
    return *this;
  }
  Log& operator<<(SamplingFilter aFilter) {
    if (MOZ_UNLIKELY(LogIt())) {
      switch (aFilter) {
        case SamplingFilter::GOOD:
          mMessage << "SamplingFilter::GOOD";
          break;
        case SamplingFilter::LINEAR:
          mMessage << "SamplingFilter::LINEAR";
          break;
        case SamplingFilter::POINT:
          mMessage << "SamplingFilter::POINT";
          break;
        default:
          mMessage << "Invalid SamplingFilter (" << (int)aFilter << ")";
          break;
      }
    }
    return *this;
  }
  Log& operator<<(AntialiasMode aMode) {
    if (MOZ_UNLIKELY(LogIt())) {
      switch (aMode) {
        case AntialiasMode::NONE:
          mMessage << "AntialiasMode::NONE";
          break;
        case AntialiasMode::GRAY:
          mMessage << "AntialiasMode::GRAY";
          break;
        case AntialiasMode::SUBPIXEL:
          mMessage << "AntialiasMode::SUBPIXEL";
          break;
        case AntialiasMode::DEFAULT:
          mMessage << "AntialiasMode::DEFAULT";
          break;
        default:
          mMessage << "Invalid AntialiasMode (" << (int)aMode << ")";
          break;
      }
    }
    return *this;
  }
  Log& operator<<(CompositionOp aOp) {
    if (MOZ_UNLIKELY(LogIt())) {
      switch (aOp) {
        case CompositionOp::OP_CLEAR:
          mMessage << "CompositionOp::OP_CLEAR";
          break;
        case CompositionOp::OP_OVER:
          mMessage << "CompositionOp::OP_OVER";
          break;
        case CompositionOp::OP_ADD:
          mMessage << "CompositionOp::OP_ADD";
          break;
        case CompositionOp::OP_ATOP:
          mMessage << "CompositionOp::OP_ATOP";
          break;
        case CompositionOp::OP_OUT:
          mMessage << "CompositionOp::OP_OUT";
          break;
        case CompositionOp::OP_IN:
          mMessage << "CompositionOp::OP_IN";
          break;
        case CompositionOp::OP_SOURCE:
          mMessage << "CompositionOp::OP_SOURCE";
          break;
        case CompositionOp::OP_DEST_IN:
          mMessage << "CompositionOp::OP_DEST_IN";
          break;
        case CompositionOp::OP_DEST_OUT:
          mMessage << "CompositionOp::OP_DEST_OUT";
          break;
        case CompositionOp::OP_DEST_OVER:
          mMessage << "CompositionOp::OP_DEST_OVER";
          break;
        case CompositionOp::OP_DEST_ATOP:
          mMessage << "CompositionOp::OP_DEST_ATOP";
          break;
        case CompositionOp::OP_XOR:
          mMessage << "CompositionOp::OP_XOR";
          break;
        case CompositionOp::OP_MULTIPLY:
          mMessage << "CompositionOp::OP_MULTIPLY";
          break;
        case CompositionOp::OP_SCREEN:
          mMessage << "CompositionOp::OP_SCREEN";
          break;
        case CompositionOp::OP_OVERLAY:
          mMessage << "CompositionOp::OP_OVERLAY";
          break;
        case CompositionOp::OP_DARKEN:
          mMessage << "CompositionOp::OP_DARKEN";
          break;
        case CompositionOp::OP_LIGHTEN:
          mMessage << "CompositionOp::OP_LIGHTEN";
          break;
        case CompositionOp::OP_COLOR_DODGE:
          mMessage << "CompositionOp::OP_COLOR_DODGE";
          break;
        case CompositionOp::OP_COLOR_BURN:
          mMessage << "CompositionOp::OP_COLOR_BURN";
          break;
        case CompositionOp::OP_HARD_LIGHT:
          mMessage << "CompositionOp::OP_HARD_LIGHT";
          break;
        case CompositionOp::OP_SOFT_LIGHT:
          mMessage << "CompositionOp::OP_SOFT_LIGHT";
          break;
        case CompositionOp::OP_DIFFERENCE:
          mMessage << "CompositionOp::OP_DIFFERENCE";
          break;
        case CompositionOp::OP_EXCLUSION:
          mMessage << "CompositionOp::OP_EXCLUSION";
          break;
        case CompositionOp::OP_HUE:
          mMessage << "CompositionOp::OP_HUE";
          break;
        case CompositionOp::OP_SATURATION:
          mMessage << "CompositionOp::OP_SATURATION";
          break;
        case CompositionOp::OP_COLOR:
          mMessage << "CompositionOp::OP_COLOR";
          break;
        case CompositionOp::OP_LUMINOSITY:
          mMessage << "CompositionOp::OP_LUMINOSITY";
          break;
        case CompositionOp::OP_COUNT:
          mMessage << "CompositionOp::OP_COUNT";
          break;
        default:
          mMessage << "Invalid CompositionOp (" << (int)aOp << ")";
          break;
      }
    }
    return *this;
  }
  Log& operator<<(SurfaceFormat aFormat) {
    if (MOZ_UNLIKELY(LogIt())) {
      switch (aFormat) {
        case SurfaceFormat::B8G8R8A8:
          mMessage << "SurfaceFormat::B8G8R8A8";
          break;
        case SurfaceFormat::B8G8R8X8:
          mMessage << "SurfaceFormat::B8G8R8X8";
          break;
        case SurfaceFormat::R8G8B8A8:
          mMessage << "SurfaceFormat::R8G8B8A8";
          break;
        case SurfaceFormat::R8G8B8X8:
          mMessage << "SurfaceFormat::R8G8B8X8";
          break;
        case SurfaceFormat::R5G6B5_UINT16:
          mMessage << "SurfaceFormat::R5G6B5_UINT16";
          break;
        case SurfaceFormat::A8:
          mMessage << "SurfaceFormat::A8";
          break;
        case SurfaceFormat::YUV:
          mMessage << "SurfaceFormat::YUV";
          break;
        case SurfaceFormat::UNKNOWN:
          mMessage << "SurfaceFormat::UNKNOWN";
          break;
        default:
          mMessage << "Invalid SurfaceFormat (" << (int)aFormat << ")";
          break;
      }
    }
    return *this;
  }

  Log& operator<<(SurfaceType aType) {
    if (MOZ_UNLIKELY(LogIt())) {
      switch (aType) {
        case SurfaceType::DATA:
          mMessage << "SurfaceType::DATA";
          break;
        case SurfaceType::D2D1_BITMAP:
          mMessage << "SurfaceType::D2D1_BITMAP";
          break;
        case SurfaceType::D2D1_DRAWTARGET:
          mMessage << "SurfaceType::D2D1_DRAWTARGET";
          break;
        case SurfaceType::CAIRO:
          mMessage << "SurfaceType::CAIRO";
          break;
        case SurfaceType::CAIRO_IMAGE:
          mMessage << "SurfaceType::CAIRO_IMAGE";
          break;
        case SurfaceType::COREGRAPHICS_IMAGE:
          mMessage << "SurfaceType::COREGRAPHICS_IMAGE";
          break;
        case SurfaceType::COREGRAPHICS_CGCONTEXT:
          mMessage << "SurfaceType::COREGRAPHICS_CGCONTEXT";
          break;
        case SurfaceType::SKIA:
          mMessage << "SurfaceType::SKIA";
          break;
        case SurfaceType::D2D1_1_IMAGE:
          mMessage << "SurfaceType::D2D1_1_IMAGE";
          break;
        case SurfaceType::RECORDING:
          mMessage << "SurfaceType::RECORDING";
          break;
        case SurfaceType::DATA_SHARED:
          mMessage << "SurfaceType::DATA_SHARED";
          break;
        case SurfaceType::DATA_RECYCLING_SHARED:
          mMessage << "SurfaceType::DATA_RECYCLING_SHARED";
          break;
        case SurfaceType::DATA_ALIGNED:
          mMessage << "SurfaceType::DATA_ALIGNED";
          break;
        case SurfaceType::DATA_SHARED_WRAPPER:
          mMessage << "SurfaceType::DATA_SHARED_WRAPPER";
          break;
        case SurfaceType::DATA_MAPPED:
          mMessage << "SurfaceType::DATA_MAPPED";
          break;
        case SurfaceType::WEBGL:
          mMessage << "SurfaceType::WEBGL";
          break;
        default:
          mMessage << "Invalid SurfaceType (" << (int)aType << ")";
          break;
      }
    }
    return *this;
  }

  inline bool LogIt() const { return mLogIt; }
  inline bool NoNewline() const {
    return mOptions & int(LogOptions::NoNewline);
  }
  inline bool AutoPrefix() const {
    return mOptions & int(LogOptions::AutoPrefix);
  }
  inline bool ValidReason() const {
    return (int)mReason > (int)LogReason::MustBeMoreThanThis &&
           (int)mReason < (int)LogReason::MustBeLessThanThis;
  }

  // We do not want this version to do any work, and stringstream can't be
  // copied anyway.  It does come in handy for the "Once" macro defined below.
  MOZ_IMPLICIT Log(const Log& log) { Init(log.mOptions, false, log.mReason); }

 private:
  // Initialization common to two constructors
  void Init(int aOptions, bool aLogIt, LogReason aReason) {
    mOptions = aOptions;
    mReason = aReason;
    mLogIt = aLogIt;
    if (mLogIt) {
      if (AutoPrefix()) {
        if (mOptions & int(LogOptions::AssertOnCall)) {
          mMessage << "[GFX" << L;
        } else {
          mMessage << "[GFX" << L << "-";
        }
      }
      if ((mOptions & int(LogOptions::CrashAction)) && ValidReason()) {
        mMessage << " " << (int)mReason;
      }
      if (AutoPrefix()) {
        mMessage << "]: ";
      }
    }
  }

  void WriteLog(const std::string& aString) {
    if (MOZ_UNLIKELY(LogIt())) {
      Logger::OutputMessage(aString, L, NoNewline());
      // Assert if required.  We don't have a three parameter MOZ_ASSERT
      // so use the underlying functions instead (see bug 1281702):
#ifdef DEBUG
      if (mOptions & int(LogOptions::AssertOnCall)) {
        MOZ_ReportAssertionFailure(aString.c_str(), __FILE__, __LINE__);
        MOZ_CRASH("GFX: An assert from the graphics logger");
      }
#endif
      if ((mOptions & int(LogOptions::CrashAction)) && ValidReason()) {
        Logger::CrashAction(mReason);
      }
    }
  }

  std::stringstream mMessage;
  int mOptions;
  LogReason mReason;
  bool mLogIt;
};

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

// Macro to glue names to get us less chance of name clashing.
#if defined GFX_LOGGING_GLUE1 || defined GFX_LOGGING_GLUE
#  error "Clash of the macro GFX_LOGGING_GLUE1 or GFX_LOGGING_GLUE"
#endif
#define GFX_LOGGING_GLUE1(x, y) x##y
#define GFX_LOGGING_GLUE(x, y) GFX_LOGGING_GLUE1(x, y)

// This log goes into crash reports, use with care.
#define gfxCriticalError mozilla::gfx::CriticalLog
#define gfxCriticalErrorOnce                                        \
  static gfxCriticalError GFX_LOGGING_GLUE(sOnceAtLine, __LINE__) = \
      gfxCriticalError

// This is a shortcut for errors we want logged in crash reports/about support
// but we do not want asserting.  These are available in all builds, so it is
// not worth trying to do magic to avoid matching the syntax of
// gfxCriticalError.
// So, this one is used as
// gfxCriticalNote << "Something to report and not assert";
// while the critical error is
// gfxCriticalError() << "Something to report and assert";
#define gfxCriticalNote \
  gfxCriticalError(gfxCriticalError::DefaultOptions(false))
#define gfxCriticalNoteOnce                                         \
  static gfxCriticalError GFX_LOGGING_GLUE(sOnceAtLine, __LINE__) = \
      gfxCriticalNote

// The "once" versions will only trigger the first time through. You can do
// this: gfxCriticalErrorOnce() << "This message only shows up once; instead of
// the usual: static bool firstTime = true; if (firstTime) {
//   firstTime = false;
//   gfxCriticalError() << "This message only shows up once;
// }
#if defined(DEBUG)
#  define gfxDebug mozilla::gfx::DebugLog
#  define gfxDebugOnce \
    static gfxDebug GFX_LOGGING_GLUE(sOnceAtLine, __LINE__) = gfxDebug
#else
#  define gfxDebug \
    if (1)         \
      ;            \
    else           \
      mozilla::gfx::NoLog
#  define gfxDebugOnce \
    if (1)             \
      ;                \
    else               \
      mozilla::gfx::NoLog
#endif

// Have gfxWarning available (behind a runtime preference)
#define gfxWarning mozilla::gfx::WarningLog
#define gfxWarningOnce \
  static gfxWarning GFX_LOGGING_GLUE(sOnceAtLine, __LINE__) = gfxWarning

// In the debug build, this is equivalent to the default gfxCriticalError.
// In the non-debug build, on nightly and dev edition, it will MOZ_CRASH.
// On beta and release versions, it will telemetry count, but proceed.
//
// You should create a (new) enum in the LogReason and use it for the reason
// parameter to ensure uniqueness.
#define gfxDevCrash(reason)                                 \
  gfxCriticalError(int(gfx::LogOptions::AutoPrefix) |       \
                       int(gfx::LogOptions::AssertOnCall) | \
                       int(gfx::LogOptions::CrashAction),   \
                   (reason))

// See nsDebug.h and the NS_WARN_IF macro

#ifdef __cplusplus
// For now, have MOZ2D_ERROR_IF available in debug and non-debug builds
inline bool MOZ2D_error_if_impl(bool aCondition, const char* aExpr,
                                const char* aFile, int32_t aLine) {
  if (MOZ_UNLIKELY(aCondition)) {
    gfxCriticalError() << aExpr << " at " << aFile << ":" << aLine;
  }
  return aCondition;
}
#  define MOZ2D_ERROR_IF(condition) \
    MOZ2D_error_if_impl(condition, #condition, __FILE__, __LINE__)

#  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;

template <int Level = LOG_DEBUG>
class TreeLog {
 public:
  explicit TreeLog(const std::string& aPrefix = "")
      : mLog(int(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) {
      if (!mPrefix.empty()) {
        mLog << '[' << mPrefix << "] ";
      }
      mLog << 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() {
    MOZ_ASSERT(mDepth > 0);
    --mDepth;
  }

  void ConditionOnPrefFunction(bool (*aPrefFunction)()) {
    mConditionedOnPref = true;
    mPrefFunction = aPrefFunction;
  }

 private:
  Log<Level> 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));
  }
};

template <int Level = LOG_DEBUG>
class TreeAutoIndent final {
 public:
  explicit TreeAutoIndent(TreeLog<Level>& aTreeLog) : mTreeLog(aTreeLog) {
    mTreeLog.IncreaseIndent();
  }

  TreeAutoIndent(const TreeAutoIndent& aTreeAutoIndent)
      : mTreeLog(aTreeAutoIndent.mTreeLog) {
    mTreeLog.IncreaseIndent();
  }

  TreeAutoIndent& operator=(const TreeAutoIndent& aTreeAutoIndent) = delete;

  ~TreeAutoIndent() { mTreeLog.DecreaseIndent(); }

 private:
  TreeLog<Level>& mTreeLog;
};

}  // namespace gfx
}  // namespace mozilla

#endif /* MOZILLA_GFX_LOGGING_H_ */