2 files changed, 105 insertions, 0 deletions
diff --git a/include/cru/base/log/Logger.h b/include/cru/base/log/Logger.h
new file mode 100644
index 00000000..25735e14
--- /dev/null
+++ b/include/cru/base/log/Logger.h
@@ -0,0 +1,88 @@
+#pragma once
+#include "../Base.h"
+
+#include "../Format.h"
+#include "../String.h"
+#include "../concurrent/ConcurrentQueue.h"
+
+#include <memory>
+#include <mutex>
+#include <thread>
+#include <vector>
+
+namespace cru::log {
+enum class LogLevel { Debug, Info, Warn, Error };
+
+struct CRU_BASE_API LogInfo {
+  LogInfo(LogLevel level, String tag, String message)
+      : level(level), tag(std::move(tag)), message(std::move(message)) {}
+
+  CRU_DEFAULT_COPY(LogInfo)
+  CRU_DEFAULT_MOVE(LogInfo)
+
+  ~LogInfo() = default;
+
+  LogLevel level;
+  String tag;
+  String message;
+};
+
+struct CRU_BASE_API ILogTarget : virtual Interface {
+  // Write the string s. LogLevel is just a helper. It has no effect on the
+  // content to write.
+  virtual void Write(LogLevel level, StringView s) = 0;
+};
+
+class CRU_BASE_API Logger : public Object {
+ public:
+  static Logger* GetInstance();
+
+ public:
+  Logger();
+
+  CRU_DELETE_COPY(Logger)
+  CRU_DELETE_MOVE(Logger)
+
+  ~Logger() override;
+
+ public:
+  void AddLogTarget(std::unique_ptr<ILogTarget> source);
+  void RemoveLogTarget(ILogTarget* source);
+
+ public:
+  void Log(LogLevel level, String tag, String message) {
+    Log(LogInfo(level, std::move(tag), std::move(message)));
+  }
+  void Log(LogInfo log_info);
+
+  template <typename... Args>
+  void FormatLog(LogLevel level, String tag, StringView format,
+                 Args&&... args) {
+    Log(level, std::move(tag), Format(format, std::forward<Args>(args)...));
+  }
+
+ private:
+  concurrent::ConcurrentQueue<LogInfo> log_queue_;
+
+  std::mutex target_list_mutex_;
+  std::vector<std::unique_ptr<ILogTarget>> target_list_;
+
+  std::thread log_thread_;
+};
+}  // namespace cru::log
+
+#define CRU_LOG_DEBUG(...)                                              \
+  cru::log::Logger::GetInstance()->FormatLog(cru::log::LogLevel::Debug, \
+                                             kLogTag, __VA_ARGS__)
+
+#define CRU_LOG_INFO(...)                                              \
+  cru::log::Logger::GetInstance()->FormatLog(cru::log::LogLevel::Info, \
+                                             kLogTag, __VA_ARGS__)
+
+#define CRU_LOG_WARN(...)                                              \
+  cru::log::Logger::GetInstance()->FormatLog(cru::log::LogLevel::Warn, \
+                                             kLogTag, __VA_ARGS__)
+
+#define CRU_LOG_ERROR(...)                                              \
+  cru::log::Logger::GetInstance()->FormatLog(cru::log::LogLevel::Error, \
+                                             kLogTag, __VA_ARGS__)
diff --git a/include/cru/base/log/StdioLogTarget.h b/include/cru/base/log/StdioLogTarget.h
new file mode 100644
index 00000000..4123766b
--- /dev/null
+++ b/include/cru/base/log/StdioLogTarget.h
@@ -0,0 +1,17 @@
+#pragma once
+#include "Logger.h"
+
+namespace cru::log {
+class StdioLogTarget : public Object, public virtual log::ILogTarget {
+ public:
+  explicit StdioLogTarget();
+
+  CRU_DELETE_COPY(StdioLogTarget)
+  CRU_DELETE_MOVE(StdioLogTarget)
+
+  ~StdioLogTarget() override;
+
+ public:
+  void Write(log::LogLevel level, StringView s) override;
+};
+}  // namespace cru::log