intermediate changes

ref:cde9a383711a11544ce7e107a78147fb96cc4029

1 files changed, 60 insertions, 0 deletions

diff --git a/util/stream/trace.h b/util/stream/trace.h
new file mode 100644
index 0000000000..e74b6ecf3e
--- /dev/null
+++ b/util/stream/trace.h
@@ -0,0 +1,60 @@
+#pragma once
+
+#include "debug.h"
+
+/**
+ * Debug level, as set via `DBGOUT` environment variable.
+ */
+enum ETraceLevel: ui8 {
+    TRACE_ERR = 1,
+    TRACE_WARN = 2,
+    TRACE_NOTICE = 3,
+    TRACE_INFO = 4,
+    TRACE_DEBUG = 5,
+    TRACE_DETAIL = 6,
+    TRACE_VERBOSE = 7
+};
+
+#if !defined(NDEBUG) && !defined(Y_ENABLE_TRACE)
+    #define Y_ENABLE_TRACE
+#endif
+
+#ifdef Y_ENABLE_TRACE
+
+    /**
+ * Writes the given data into standard debug stream if current debug level set
+ * via `DBGOUT` environment variable permits it.
+ *
+ * Does nothing in release builds unless `Y_ENABLE_TRACE` is defined.
+ *
+ * Example usage:
+ * @code
+ * Y_DBGTRACE(DEBUG, "Advance from " << node1 << " to " << node2);
+ * @endcode
+ *
+ * @param elevel                        Debug level of this trace command, e.g.
+ *                                      `WARN` or `DEBUG`. Basically a suffix of
+ *                                      one of the values of `ETraceLevel` enum.
+ * @param args                          Argument chain to be written out into
+ *                                      standard debug stream, joined with `<<`
+ *                                      operator.
+ * @see ETraceLevel
+ */
+    #define Y_DBGTRACE(elevel, args) Y_DBGTRACE0(int(TRACE_##elevel), args)
+    #define Y_DBGTRACE0(level, args)            \
+        do                                      \
+            if ((level) <= StdDbgLevel()) {     \
+                StdDbgStream() << args << Endl; \
+            }                                   \
+        while (false)
+
+#else
+
+    #define Y_DBGTRACE(elevel, args) \
+        do {                         \
+        } while (false)
+    #define Y_DBGTRACE0(level, args) \
+        do {                         \
+        } while (false)
+
+#endif