src/diagnostic/printer_windows.cc

// 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.

#include <cstring>

#include "src/diagnostic/printer.h"

#define WIN32_LEAN_AND_MEAN 1
#include <Windows.h>

namespace tint {
namespace diag {
namespace {

struct ConsoleInfo {
  HANDLE handle = INVALID_HANDLE_VALUE;
  WORD default_attributes = 0;
  operator bool() const { return handle != INVALID_HANDLE_VALUE; }
};

ConsoleInfo console_info(FILE* file) {
  if (file == nullptr) {
    return {};
  }

  ConsoleInfo console{};
  if (file == stdout) {
    console.handle = GetStdHandle(STD_OUTPUT_HANDLE);
  } else if (file == stderr) {
    console.handle = GetStdHandle(STD_ERROR_HANDLE);
  } else {
    return {};
  }

  CONSOLE_SCREEN_BUFFER_INFO info{};
  if (GetConsoleScreenBufferInfo(console.handle, &info) == 0) {
    return {};
  }

  console.default_attributes = info.wAttributes;
  return console;
}

class PrinterWindows : public Printer {
 public:
  PrinterWindows(FILE* f, bool use_colors)
      : file(f), console(console_info(use_colors ? f : nullptr)) {}

  void write(const std::string& str, const Style& style) override {
    write_color(style.color, style.bold);
    fwrite(str.data(), 1, str.size(), file);
    write_color(Color::kDefault, false);
  }

 private:
  WORD attributes(Color color, bool bold) {
    switch (color) {
      case Color::kDefault:
        return console.default_attributes;
      case Color::kBlack:
        return 0;
      case Color::kRed:
        return FOREGROUND_RED | (bold ? FOREGROUND_INTENSITY : 0);
      case Color::kGreen:
        return FOREGROUND_GREEN | (bold ? FOREGROUND_INTENSITY : 0);
      case Color::kYellow:
        return FOREGROUND_RED | FOREGROUND_GREEN |
               (bold ? FOREGROUND_INTENSITY : 0);
      case Color::kBlue:
        return FOREGROUND_BLUE | (bold ? FOREGROUND_INTENSITY : 0);
      case Color::kMagenta:
        return FOREGROUND_RED | FOREGROUND_BLUE |
               (bold ? FOREGROUND_INTENSITY : 0);
      case Color::kCyan:
        return FOREGROUND_GREEN | FOREGROUND_BLUE |
               (bold ? FOREGROUND_INTENSITY : 0);
      case Color::kWhite:
        return FOREGROUND_RED | FOREGROUND_GREEN | FOREGROUND_BLUE |
               (bold ? FOREGROUND_INTENSITY : 0);
    }
    return 0;  // unreachable
  }

  void write_color(Color color, bool bold) {
    if (console) {
      SetConsoleTextAttribute(console.handle, attributes(color, bold));
      fflush(file);
    }
  }

  FILE* const file;
  const ConsoleInfo console;
};

}  // namespace

std::unique_ptr<Printer> Printer::create(FILE* out, bool use_colors) {
  return std::make_unique<PrinterWindows>(out, use_colors);
}

}  // namespace diag
}  // namespace tint