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      1 //===- WithColor.h ----------------------------------------------*- C++ -*-===//
      2 //
      3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
      4 // See https://llvm.org/LICENSE.txt for license information.
      5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
      6 //
      7 //===----------------------------------------------------------------------===//
      8 
      9 #ifndef LLVM_SUPPORT_WITHCOLOR_H
     10 #define LLVM_SUPPORT_WITHCOLOR_H
     11 
     12 #include "llvm/Support/raw_ostream.h"
     13 
     14 namespace llvm {
     15 
     16 class Error;
     17 class StringRef;
     18 
     19 namespace cl {
     20 class OptionCategory;
     21 }
     22 
     23 extern cl::OptionCategory ColorCategory;
     24 
     25 // Symbolic names for various syntax elements.
     26 enum class HighlightColor {
     27   Address,
     28   String,
     29   Tag,
     30   Attribute,
     31   Enumerator,
     32   Macro,
     33   Error,
     34   Warning,
     35   Note,
     36   Remark
     37 };
     38 
     39 enum class ColorMode {
     40   /// Determine whether to use color based on the command line argument and the
     41   /// raw_ostream.
     42   Auto,
     43   /// Enable colors. Because raw_ostream is the one implementing colors, this
     44   /// has no effect if the stream does not support colors or has colors
     45   /// disabled.
     46   Enable,
     47   /// Disable colors.
     48   Disable,
     49 };
     50 
     51 /// An RAII object that temporarily switches an output stream to a specific
     52 /// color.
     53 class WithColor {
     54   raw_ostream &OS;
     55   ColorMode Mode;
     56 
     57 public:
     58   /// To be used like this: WithColor(OS, HighlightColor::String) << "text";
     59   /// @param OS The output stream
     60   /// @param S Symbolic name for syntax element to color
     61   /// @param Mode Enable, disable or compute whether to use colors.
     62   WithColor(raw_ostream &OS, HighlightColor S,
     63             ColorMode Mode = ColorMode::Auto);
     64   /// To be used like this: WithColor(OS, raw_ostream::Black) << "text";
     65   /// @param OS The output stream
     66   /// @param Color ANSI color to use, the special SAVEDCOLOR can be used to
     67   /// change only the bold attribute, and keep colors untouched
     68   /// @param Bold Bold/brighter text, default false
     69   /// @param BG If true, change the background, default: change foreground
     70   /// @param Mode Enable, disable or compute whether to use colors.
     71   WithColor(raw_ostream &OS,
     72             raw_ostream::Colors Color = raw_ostream::SAVEDCOLOR,
     73             bool Bold = false, bool BG = false,
     74             ColorMode Mode = ColorMode::Auto)
     75       : OS(OS), Mode(Mode) {
     76     changeColor(Color, Bold, BG);
     77   }
     78   ~WithColor();
     79 
     80   raw_ostream &get() { return OS; }
     81   operator raw_ostream &() { return OS; }
     82   template <typename T> WithColor &operator<<(T &O) {
     83     OS << O;
     84     return *this;
     85   }
     86   template <typename T> WithColor &operator<<(const T &O) {
     87     OS << O;
     88     return *this;
     89   }
     90 
     91   /// Convenience method for printing "error: " to stderr.
     92   static raw_ostream &error();
     93   /// Convenience method for printing "warning: " to stderr.
     94   static raw_ostream &warning();
     95   /// Convenience method for printing "note: " to stderr.
     96   static raw_ostream &note();
     97   /// Convenience method for printing "remark: " to stderr.
     98   static raw_ostream &remark();
     99 
    100   /// Convenience method for printing "error: " to the given stream.
    101   static raw_ostream &error(raw_ostream &OS, StringRef Prefix = "",
    102                             bool DisableColors = false);
    103   /// Convenience method for printing "warning: " to the given stream.
    104   static raw_ostream &warning(raw_ostream &OS, StringRef Prefix = "",
    105                               bool DisableColors = false);
    106   /// Convenience method for printing "note: " to the given stream.
    107   static raw_ostream &note(raw_ostream &OS, StringRef Prefix = "",
    108                            bool DisableColors = false);
    109   /// Convenience method for printing "remark: " to the given stream.
    110   static raw_ostream &remark(raw_ostream &OS, StringRef Prefix = "",
    111                              bool DisableColors = false);
    112 
    113   /// Determine whether colors are displayed.
    114   bool colorsEnabled();
    115 
    116   /// Change the color of text that will be output from this point forward.
    117   /// @param Color ANSI color to use, the special SAVEDCOLOR can be used to
    118   /// change only the bold attribute, and keep colors untouched
    119   /// @param Bold Bold/brighter text, default false
    120   /// @param BG If true, change the background, default: change foreground
    121   WithColor &changeColor(raw_ostream::Colors Color, bool Bold = false,
    122                          bool BG = false);
    123 
    124   /// Reset the colors to terminal defaults. Call this when you are done
    125   /// outputting colored text, or before program exit.
    126   WithColor &resetColor();
    127 
    128   /// Implement default handling for Error.
    129   /// Print "error: " to stderr.
    130   static void defaultErrorHandler(Error Err);
    131 
    132   /// Implement default handling for Warning.
    133   /// Print "warning: " to stderr.
    134   static void defaultWarningHandler(Error Warning);
    135 };
    136 
    137 } // end namespace llvm
    138 
    139 #endif // LLVM_SUPPORT_WITHCOLOR_H
    140