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#include "logger.hh"
#include <cstdint>
#include <format>
#include <iostream>
#include <memory>
#include <string>
#include <string_view>
#include <utility>
namespace logger {
namespace {
class BaseLogger : public Logger {
protected:
enum class Level : uint8_t {
kError,
kWarning,
kInfo,
kDebug,
};
public:
void err(std::string_view message) final { write(Level::kError, message); }
void warn(std::string_view message) final { write(Level::kWarning, message); }
void info(std::string_view message) final { write(Level::kInfo, message); }
#ifndef NDEBUG
void dbg(std::string_view message) final { write(Level::kDebug, message); }
#endif
protected:
BaseLogger() = default;
virtual void write(Level level, std::string_view message) = 0;
};
class NoopLogger : public BaseLogger {
public:
NoopLogger() = default;
protected:
void write(Level /* level */, std::string_view /* message */) override {}
};
class StderrLogger : public BaseLogger {
public:
explicit StderrLogger(bool verbose) : verbose_(verbose) {}
protected:
void write(Level level, std::string_view message) override {
switch (level) {
case Level::kError:
std::cerr << "Error: ";
break;
case Level::kWarning:
std::cerr << "Warning: ";
break;
case Level::kInfo:
if (!verbose_)
return;
std::cerr << "Info: ";
break;
case Level::kDebug:
if (!verbose_)
return;
std::cerr << "Debug: ";
break;
}
std::cerr << message << '\n';
}
private:
bool const verbose_;
};
class PrefixLogger : public Logger {
public:
PrefixLogger(Logger& logger, std::string prefix)
: logger_(logger), prefix_(std::move(prefix)) {}
void err(std::string_view message) override {
logger_.err(std::format("{}: {}", prefix_, message));
}
void warn(std::string_view message) override {
logger_.warn(std::format("{}: {}", prefix_, message));
}
void info(std::string_view message) override {
logger_.info(std::format("{}: {}", prefix_, message));
}
#ifndef NDEBUG
void dbg(std::string_view message) override {
logger_.dbg(std::format("{}: {}", prefix_, message));
}
#endif
private:
Logger& logger_;
std::string prefix_;
};
} // namespace
[[nodiscard]]
std::unique_ptr<Logger> noop() {
return std::make_unique<NoopLogger>();
}
[[nodiscard]]
std::unique_ptr<Logger> stderr(bool verbose) {
return std::make_unique<StderrLogger>(verbose);
}
[[nodiscard]]
std::unique_ptr<Logger> prefix(Logger& logger, std::string prefix) {
return std::make_unique<PrefixLogger>(logger, std::move(prefix));
}
} // namespace logger
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