From 7463e54258c1b8a0ee6b8557081d2e00ef81b826 Mon Sep 17 00:00:00 2001
From: Eugene Bujak <hmage@hmage.net>
Date: Sat, 29 Dec 2018 17:23:08 +0300
Subject: [PATCH] Implement a log wrapper

---
 log/log.go | 35 +++++++++++++++++++++++++++++++++++
 1 file changed, 35 insertions(+)
 create mode 100644 log/log.go

diff --git a/log/log.go b/log/log.go
new file mode 100644
index 00000000..db6132e7
--- /dev/null
+++ b/log/log.go
@@ -0,0 +1,35 @@
+// Wrapper for standard library log, with the only difference is that it has extra function Tracef() and optional verbose flag to enable output from that.
+package log
+
+import (
+	"fmt"
+	"log"
+	"os"
+	"path"
+	"runtime"
+	"strings"
+)
+
+var Verbose = false
+
+// Printf calls Output to print to the standard logger.
+// Arguments are handled in the manner of fmt.Printf.
+func Printf(format string, v ...interface{}) {
+	log.Printf(format, v...)
+}
+
+func Tracef(format string, v ...interface{}) {
+	if Verbose {
+		pc := make([]uintptr, 10) // at least 1 entry needed
+		runtime.Callers(2, pc)
+		f := runtime.FuncForPC(pc[0])
+		var buf strings.Builder
+		buf.WriteString(fmt.Sprintf("%s(): ", path.Base(f.Name())))
+		text := fmt.Sprintf(format, v...)
+		buf.WriteString(text)
+		if len(text) == 0 || text[len(text)-1] != '\n' {
+			buf.WriteRune('\n')
+		}
+		fmt.Fprint(os.Stderr, buf.String())
+	}
+}