add new subsystem interface, Logger

iface/CMakeLists.txt

@@ -21,6 +21,7 @@ target_sources(nf7_iface
     data/interface.hh
     subsys/concurrency.hh
     subsys/interface.hh
+    subsys/logger.hh
     subsys/parallelism.hh
     env.hh
     file.hh
@@ -40,6 +41,7 @@ target_sources(nf7_iface_test
     common/task_test.cc
     common/task_test.hh
     common/value_test.cc
+    subsys/logger_test.hh
     lambda_test.cc
     lambda_test.hh
 )

iface/subsys/logger.hh

@@ -0,0 +1,80 @@
+// No copyright
+#pragma once
+
+#include <source_location>
+#include <string>
+#include <string_view>
+
+#include "iface/subsys/interface.hh"
+
+
+namespace nf7::subsys {
+
+class Logger : public Interface {
+ public:
+  using SrcLoc = std::source_location;
+
+  enum Level {
+    kTrace,
+    kInfo,
+    kWarn,
+    kError,
+  };
+
+  class Item final {
+   public:
+    Item() = delete;
+    Item(Level level,
+         std::string_view contents,
+         std::source_location srcloc = std::source_location::current()) noexcept
+        : level_(level), contents_(contents), srcloc_(srcloc) { }
+
+    Item(const Item&) = default;
+    Item(Item&&) = default;
+    Item& operator=(const Item&) = default;
+    Item& operator=(Item&&) = default;
+
+    Level level() const noexcept { return level_; }
+    const std::string& contents() const noexcept { return contents_; }
+    const std::source_location& srcloc() const noexcept { return srcloc_; }
+
+   private:
+    Level level_;
+    std::string contents_;
+    std::source_location srcloc_;
+  };
+
+ public:
+  using Interface::Interface;
+
+ public:
+  // THREAD-SAFE
+  virtual void Push(const Item&) noexcept = 0;
+
+  // THREAD-SAFE
+  void Trace(std::string_view contents,
+             SrcLoc srcloc = SrcLoc::current()) noexcept {
+    Push(Item {kTrace, contents, srcloc});
+  }
+
+  // THREAD-SAFE
+  void Info(std::string_view contents,
+            SrcLoc srcloc = SrcLoc::current()) noexcept {
+    Push(Item {kInfo, contents, srcloc});
+  }
+
+  // THREAD-SAFE
+  void Warn(std::string_view contents,
+            SrcLoc srcloc = SrcLoc::current()) noexcept {
+    Push(Item {kWarn, contents, srcloc});
+  }
+
+  // THREAD-SAFE
+  void Error(std::string_view contents,
+             SrcLoc srcloc = SrcLoc::current()) noexcept {
+    Push(Item {kError, contents, srcloc});
+  }
+};
+
+
+}  // namespace nf7::subsys

iface/subsys/logger_test.hh

@@ -0,0 +1,19 @@
+// No copyright
+#pragma once
+
+#include "iface/subsys/logger.hh"
+
+#include <gmock/gmock.h>
+
+
+namespace nf7::subsys::test {
+
+class LoggerMock : public Logger {
+ public:
+  explicit LoggerMock(const char* name = "LoggerMock") noexcept
+      : Logger(name) {}
+
+  MOCK_METHOD(void, Push, (const Item&), (noexcept));
+};
+
+}  // namespace nf7::subsys::test