chore: import upstream snapshot with attribution

cpp/include/ray/api/logging.h

@@ -0,0 +1,83 @@
+// Copyright 2017 The Ray 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.
+
+#pragma once
+
+#include <iostream>
+#include <memory>
+
+#if defined(_WIN32)
+#ifndef _WINDOWS_
+// This is a public header that may be compiled outside of Ray's build system,
+// so we cannot rely on the -DWIN32_LEAN_AND_MEAN compiler flag from ray.bzl.
+#ifndef WIN32_LEAN_AND_MEAN
+#define WIN32_LEAN_AND_MEAN  // Prevent Windows.h from including WinSock.h
+#endif
+#include <Windows.h>  // Force inclusion of WinGDI here to resolve name conflict
+#endif
+#ifdef ERROR  // Should be true unless someone else undef'd it already
+#undef ERROR  // Windows GDI defines this macro; make it a global enum so it doesn't
+              // conflict with our code
+enum { ERROR = 0 };
+#endif
+#endif
+
+#if defined(DEBUG) && DEBUG == 1
+// Bazel defines the DEBUG macro for historical reasons:
+// https://github.com/bazelbuild/bazel/issues/3513#issuecomment-323829248
+// Undefine the DEBUG macro to prevent conflicts with our usage below
+#undef DEBUG
+// Redefine DEBUG as itself to allow any '#ifdef DEBUG' to keep working regardless
+#define DEBUG DEBUG
+#endif
+
+namespace ray {
+
+enum class RayLoggerLevel { DEBUG = -1, INFO = 0, WARNING = 1, ERROR = 2, FATAL = 3 };
+
+#define RAYLOG_INTERNAL(level) *CreateRayLogger(__FILE__, __LINE__, level)
+#define RAYLOG(level)                             \
+  if (IsLevelEnabled(ray::RayLoggerLevel::level)) \
+  RAYLOG_INTERNAL(ray::RayLoggerLevel::level)
+
+// To make the logging lib pluggable with other logging libs and make
+// the implementation unaware by the user, RayLog is only a declaration
+// which hides the implementation into logging.cc file.
+// In logging.cc, we can choose different log libs using different macros.
+
+// This is a log interface which does not output anything.
+class RayLogger {
+ public:
+  virtual ~RayLogger(){};
+
+  virtual bool IsEnabled() const = 0;
+
+  template <typename T>
+  RayLogger &operator<<(const T &t) {
+    if (IsEnabled()) {
+      Stream() << t;
+    }
+    return *this;
+  }
+
+ protected:
+  virtual std::ostream &Stream() = 0;
+};
+
+std::unique_ptr<RayLogger> CreateRayLogger(const char *file_name,
+                                           int line_number,
+                                           RayLoggerLevel severity);
+bool IsLevelEnabled(RayLoggerLevel log_level);
+
+}  // namespace ray