Added API for accessing structs in a thread-safe way

3 files changed, 291 insertions, 1 deletions

diff --git a/src/syncedsettings.h b/src/syncedsettings.h
new file mode 100644
index 0000000..f83847c
--- /dev/null
+++ b/src/syncedsettings.h
@@ -0,0 +1,112 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/***************************************************************************
+ *            syncedsettings.h
+ *
+ *  Thu Mar 31 09:23:27 CEST 2016
+ *  Copyright 2016 Christian Glöckner
+ *  cgloeckner@freenet.de
+ ****************************************************************************/
+
+/*
+ *  This file is part of DrumGizmo.
+ *
+ *  DrumGizmo is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU Lesser General Public License as published by
+ *  the Free Software Foundation; either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  DrumGizmo is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU Lesser General Public License for more details.
+ *
+ *  You should have received a copy of the GNU Lesser General Public License
+ *  along with DrumGizmo; if not, write to the Free Software
+ *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA.
+ */
+#pragma once
+
+#include <mutex>
+
+// type trait helper
+
+template <typename T, typename... Types>
+struct pack_contains;
+
+template <typename T, typename... Types>
+struct pack_contains<T, T, Types...>
+	: std::true_type {
+};
+
+template <typename T, typename Head, typename... Types>
+struct pack_contains<T, Head, Types...>
+	: pack_contains<T, Types...> {
+};
+
+template <typename T>
+struct pack_contains<T>
+	: std::false_type {
+};
+
+// --------------------------------------------------------------------
+
+template <typename T>
+class Group;
+
+template <typename T>
+class Accessor {
+	private:
+		std::lock_guard<std::mutex> lock;
+		
+	public:
+		Accessor(Group<T>& parent)
+			: lock{parent.mutex}
+			, data{parent.data} {
+		}
+		
+		T& data;
+};
+
+template <typename T>
+class Group {
+	private:
+		friend class Accessor<T>;
+		
+		mutable std::mutex mutex;
+		T data;
+		
+	public:
+		Group()
+			: mutex{}
+			,  data{} {
+		}
+		
+		Group(T const & data)
+			: mutex{}
+			, data{data} {
+		}
+		
+		Group(T&& data)
+			: mutex{}
+			, data{std::move(data)} {
+		}
+		
+		Group(Group<T> const & other)
+			: mutex{}
+			, data{} {
+			std::lock_guard<std::mutex> lock{other.mutex};
+			data = other.data;
+		}
+		
+		Group(Group<T>&& other)
+			: mutex{}
+			, data{} {
+			std::lock_guard<std::mutex> lock{other.mutex};
+			std::swap(data, other.data);
+		}
+		
+		operator T() const {
+			std::lock_guard<std::mutex> lock{mutex};
+			return data;
+		}
+};
diff --git a/test/Makefile.am b/test/Makefile.am
index ea0912b..f9d9c77 100644
--- a/test/Makefile.am
+++ b/test/Makefile.am
@@ -3,7 +3,7 @@ include $(top_srcdir)/src/Makefile.am.drumgizmo
 
 TESTS = resource engine gui resampler lv2 configfile audiocache \
 	audiocachefile audiocacheidmanager audiocacheeventhandler \
-	memchecker random atomictest
+	memchecker random atomictest syncedsettingstest
 
 check_PROGRAMS = $(TESTS)
 
@@ -143,5 +143,10 @@ atomictest_CXXFLAGS = -DOUTPUT=\"atomictest\" $(CPPUNIT_CFLAGS) \
 atomictest_LDFLAGS = $(CPPUNIT_LIBS)
 atomictest_SOURCES = atomictest.cc test.cc
 
+syncedsettingstest_CXXFLAGS = -DOUTPUT=\"syncedsettingstest\" $(CPPUNIT_CFLAGS) \
+	-I$(top_srcdir)/src -I$(top_srcdir)/hugin
+syncedsettingstest_LDFLAGS = $(CPPUNIT_LIBS)
+syncedsettingstest_SOURCES = syncedsettings.cc test.cc
+
 EXTRA_DIST = \
 	lv2_test_host.h
diff --git a/test/syncedsettings.cc b/test/syncedsettings.cc
new file mode 100644
index 0000000..a04c870
--- /dev/null
+++ b/test/syncedsettings.cc
@@ -0,0 +1,173 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/***************************************************************************
+ *            syncedsettings.cc
+ *
+ *  Wed Mar 31 09:32:12 CET 2016
+ *  Copyright 2016 Christian Glöckner
+ *  cgloeckner@freenet.de
+ ****************************************************************************/
+
+/*
+ *  This file is part of DrumGizmo.
+ *
+ *  DrumGizmo is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  DrumGizmo is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with DrumGizmo; if not, write to the Free Software
+ *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA.
+ */
+#include <cppunit/extensions/HelperMacros.h>
+
+#include <syncedsettings.h>
+
+class SyncedSettingsTest
+	: public CppUnit::TestFixture {
+		
+	CPPUNIT_TEST_SUITE(SyncedSettingsTest);
+	CPPUNIT_TEST(groupCanBeDefaultInitialized);
+	CPPUNIT_TEST(groupDataCanBeCopied);
+	CPPUNIT_TEST(groupCanBeCreatedByReference);
+	CPPUNIT_TEST(groupCanBeCreatedByRvalueReference);
+	
+	CPPUNIT_TEST(accessorCanGetFields);
+	CPPUNIT_TEST(accessorCanSetFields);
+	
+	CPPUNIT_TEST(groupHasCopyCtor);
+	CPPUNIT_TEST(groupHasMoveCtor);
+	CPPUNIT_TEST(groupHasCopyAssignOp);
+	CPPUNIT_TEST(groupHasMoveAssignOp);
+	CPPUNIT_TEST_SUITE_END();
+	
+	private:
+		struct TestData {
+			float foo;
+			bool bar;
+			std::string msg;
+		};
+	
+	public:
+		void setUp() {}
+		void tearDown() {}
+		
+		void groupCanBeDefaultInitialized() {
+			Group<TestData> data;
+		}
+		
+		void groupDataCanBeCopied() {
+			Group<TestData> data;
+			(TestData)data; // copies
+		}
+		
+		void groupCanBeCreatedByReference() {
+			TestData tmp{3.f, false, "hello"};
+			Group<TestData> data{tmp};
+			TestData copy = data;
+			CPPUNIT_ASSERT_EQUAL(copy.foo, 3.f);
+			CPPUNIT_ASSERT_EQUAL(copy.bar, false);
+			CPPUNIT_ASSERT_EQUAL(copy.msg, std::string{"hello"});
+		}
+		
+		void groupCanBeCreatedByRvalueReference() {
+			TestData tmp{3.f, false, "hello"};
+			Group<TestData> data{std::move(tmp)};
+			TestData copy = data;
+			CPPUNIT_ASSERT_EQUAL(copy.foo, 3.f);
+			CPPUNIT_ASSERT_EQUAL(copy.bar, false);
+			CPPUNIT_ASSERT_EQUAL(copy.msg, std::string{"hello"});
+		}
+		
+		void accessorCanGetFields() {
+			TestData tmp{3.f, false, "hello"};
+			Group<TestData> data{tmp};
+			Accessor<TestData> a{data};
+			CPPUNIT_ASSERT_EQUAL(a.data.foo, 3.f);
+			CPPUNIT_ASSERT_EQUAL(a.data.bar, false);
+			CPPUNIT_ASSERT_EQUAL(a.data.msg, std::string{"hello"});
+		}
+		
+		void accessorCanSetFields() {
+			Group<TestData> data;
+			Accessor<TestData> a{data};
+			a.data.foo = 3.f;
+			a.data.bar = false;
+			a.data.msg = "hello";
+			TestData copy = data;
+			CPPUNIT_ASSERT_EQUAL(copy.foo, 3.f);
+			CPPUNIT_ASSERT_EQUAL(copy.bar, false);
+			CPPUNIT_ASSERT_EQUAL(copy.msg, std::string{"hello"});
+		}
+	
+		void groupHasCopyCtor() {
+			Group<TestData> tmp;
+			{
+				Accessor<TestData> a{tmp};
+				a.data.foo = 3.f;
+				a.data.bar = false;
+				a.data.msg = "hello";
+			}
+			Group<TestData> data{tmp};
+			TestData copy = data;
+			CPPUNIT_ASSERT_EQUAL(copy.foo, 3.f);
+			CPPUNIT_ASSERT_EQUAL(copy.bar, false);
+			CPPUNIT_ASSERT_EQUAL(copy.msg, std::string{"hello"});
+		}
+		
+		void groupHasMoveCtor() {
+			Group<TestData> tmp;
+			{
+				Accessor<TestData> a{tmp};
+				a.data.foo = 3.f;
+				a.data.bar = false;
+				a.data.msg = "hello";
+			}
+			Group<TestData> data{std::move(tmp)};
+			TestData copy = data;
+			CPPUNIT_ASSERT_EQUAL(copy.foo, 3.f);
+			CPPUNIT_ASSERT_EQUAL(copy.bar, false);
+			CPPUNIT_ASSERT_EQUAL(copy.msg, std::string{"hello"});
+		}
+		
+		void groupHasCopyAssignOp() {
+			Group<TestData> tmp;
+			{
+				Accessor<TestData> a{tmp};
+				a.data.foo = 3.f;
+				a.data.bar = false;
+				a.data.msg = "hello";
+			}
+			Group<TestData> data = tmp;
+			TestData copy = data;
+			CPPUNIT_ASSERT_EQUAL(copy.foo, 3.f);
+			CPPUNIT_ASSERT_EQUAL(copy.bar, false);
+			CPPUNIT_ASSERT_EQUAL(copy.msg, std::string{"hello"});
+		}
+		
+		void groupHasMoveAssignOp() {
+			Group<TestData> tmp;
+			{
+				Accessor<TestData> a{tmp};
+				a.data.foo = 3.f;
+				a.data.bar = false;
+				a.data.msg = "hello";
+			}
+			Group<TestData> data = std::move(tmp);
+			TestData copy = data;
+			CPPUNIT_ASSERT_EQUAL(copy.foo, 3.f);
+			CPPUNIT_ASSERT_EQUAL(copy.bar, false);
+			CPPUNIT_ASSERT_EQUAL(copy.msg, std::string{"hello"});
+		}
+		
+		// todo: further testing
+};
+
+// Registers the fixture into the 'registry'
+CPPUNIT_TEST_SUITE_REGISTRATION(SyncedSettingsTest);
+