src/diagnostic/printer.h

// Copyright 2020 The Tint Authors.
//
// 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.

#ifndef SRC_DIAGNOSTIC_PRINTER_H_
#define SRC_DIAGNOSTIC_PRINTER_H_

#include <memory>
#include <sstream>
#include <string>

namespace tint {
namespace diag {

class List;

/// Color is an enumerator of colors used by Style.
enum class Color {
  kDefault,
  kBlack,
  kRed,
  kGreen,
  kYellow,
  kBlue,
  kMagenta,
  kCyan,
  kWhite,
};

/// Style describes how a diagnostic message should be printed.
struct Style {
  /// The foreground text color
  Color color = Color::kDefault;
  /// If true the text will be displayed with a strong weight
  bool bold = false;
};

/// Printers are used to print formatted diagnostic messages to a terminal.
class Printer {
 public:
  /// @returns a diagnostic Printer
  /// @param out the file to print to.
  /// @param use_colors if true, the printer will use colors if `out` is a
  /// terminal and supports them.
  static std::unique_ptr<Printer> create(FILE* out, bool use_colors);

  virtual ~Printer();

  /// writes the string str to the printer with the given style.
  /// @param str the string to write to the printer
  /// @param style the style used to print `str`
  virtual void write(const std::string& str, const Style& style) = 0;
};

/// StringPrinter is an implementation of Printer that writes to a std::string.
class StringPrinter : public Printer {
 public:
  StringPrinter();
  ~StringPrinter() override;

  /// @returns the printed string.
  std::string str() const;

  void write(const std::string& str, const Style&) override;

 private:
  std::stringstream stream;
};

}  // namespace diag
}  // namespace tint

#endif  // SRC_DIAGNOSTIC_PRINTER_H_