From 4ceab5803aecdfa32f940827f78ea451bdd9f6a7 Mon Sep 17 00:00:00 2001
From: Denis Arh <denis.arh@gmail.com>
Date: Wed, 14 Jul 2021 21:24:46 +0200
Subject: [PATCH] Add dev/debug friendly version of sync.RWMutex

---
 pkg/dev/mutex.go | 66 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 66 insertions(+)
 create mode 100644 pkg/dev/mutex.go

diff --git a/pkg/dev/mutex.go b/pkg/dev/mutex.go
new file mode 100644
index 000000000..f82fe6db5
--- /dev/null
+++ b/pkg/dev/mutex.go
@@ -0,0 +1,66 @@
+package dev
+
+import (
+	"strconv"
+	"sync"
+
+	"go.uber.org/atomic"
+	"go.uber.org/zap"
+)
+
+type (
+	// DebugMutex for verbose locking & unlocking
+	// use:
+	// dev.DebugMutex{Logger: logger.Default()}
+	DebugMutex struct {
+		sync.RWMutex
+		c      atomic.Int64
+		Logger *zap.Logger
+	}
+)
+
+func (m *DebugMutex) log(r, u, done bool) {
+	msg := "#" + strconv.FormatInt(m.c.Load(), 10)
+	if u {
+		msg = "UNLOCK " + msg
+	} else {
+		msg = "  LOCK " + msg
+	}
+
+	if r {
+		msg = "R" + msg
+	} else {
+		msg = " " + msg
+	}
+	if done {
+		msg += " DONE"
+	}
+
+	m.Logger.WithOptions(zap.AddCallerSkip(2)).Debug(msg)
+}
+
+func (m *DebugMutex) RLock() {
+	m.c.Inc()
+	m.log(true, false, false)
+	m.RWMutex.RLock()
+	m.log(true, false, true)
+}
+
+func (m *DebugMutex) RUnlock() {
+	m.log(true, true, false)
+	m.RWMutex.RUnlock()
+	m.log(true, true, true)
+}
+
+func (m *DebugMutex) Lock() {
+	m.c.Inc()
+	m.log(true, false, false)
+	m.RWMutex.Lock()
+	m.log(true, false, true)
+}
+
+func (m *DebugMutex) Unlock() {
+	m.log(true, true, false)
+	m.RWMutex.Unlock()
+	m.log(true, true, true)
+}