From 3d126cd9a7f9029e199e9220e2ffa08ac4e23227 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Fr=C3=A9d=C3=A9ric=20Bri=C3=A8re?= <fbriere@fbriere.net>
Date: Wed, 2 Oct 2019 22:13:56 -0400
Subject: Create t_rwmutex_guard base class

(Doing this ahead of time to simplify the next commit a bit.)
---
 src/threads/mutex.cpp | 11 +++++++++--
 src/threads/mutex.h   | 15 ++++++++++-----
 2 files changed, 19 insertions(+), 7 deletions(-)

diff --git a/src/threads/mutex.cpp b/src/threads/mutex.cpp
index 9c6a762..7eaa329 100644
--- a/src/threads/mutex.cpp
+++ b/src/threads/mutex.cpp
@@ -129,7 +129,13 @@ void t_rwmutex::unlock()
 // t_rwmutex_guard
 ///////////////////////////
 
-t_rwmutex_reader::t_rwmutex_reader(t_rwmutex& mutex) : _mutex(mutex)
+t_rwmutex_guard::t_rwmutex_guard(t_rwmutex& mutex) :
+	_mutex(mutex)
+{
+}
+
+t_rwmutex_reader::t_rwmutex_reader(t_rwmutex& mutex) :
+	t_rwmutex_guard(mutex)
 {
 	// std::cout << "mtx rd lock " << (void*)&_mutex << std::endl;
 	_mutex.lockRead();
@@ -141,7 +147,8 @@ t_rwmutex_reader::~t_rwmutex_reader()
 	_mutex.unlock();
 }
 
-t_rwmutex_writer::t_rwmutex_writer(t_rwmutex& mutex) : _mutex(mutex)
+t_rwmutex_writer::t_rwmutex_writer(t_rwmutex& mutex) :
+	t_rwmutex_guard(mutex)
 {
 	// std::cout << "mtx wr lock " << (void*)&_mutex << std::endl;
 	_mutex.lockWrite();
diff --git a/src/threads/mutex.h b/src/threads/mutex.h
index 15d5181..d757d61 100644
--- a/src/threads/mutex.h
+++ b/src/threads/mutex.h
@@ -95,17 +95,22 @@ public:
 	void unlock();
 };
 
-class t_rwmutex_reader {
-private:
+// Base (abstract) class
+class t_rwmutex_guard {
+protected:
 	t_rwmutex& _mutex;
+
+	// A protected constructor to keep this class abstract
+	t_rwmutex_guard(t_rwmutex& mutex);
+};
+
+class t_rwmutex_reader : public t_rwmutex_guard {
 public:
 	t_rwmutex_reader(t_rwmutex& mutex);
 	~t_rwmutex_reader();
 };
 
-class t_rwmutex_writer {
-private:
-	t_rwmutex& _mutex;
+class t_rwmutex_writer : public t_rwmutex_guard {
 public:
 	t_rwmutex_writer(t_rwmutex& mutex);
 	~t_rwmutex_writer();
-- 
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