From ab7ab9e52ab87963831f90ab25957d883878654d Mon Sep 17 00:00:00 2001
From: Bent Bisballe Nyeng <deva@aasimon.org>
Date: Thu, 2 Jun 2016 21:00:37 +0200
Subject: New ImageCache class for reusing Image resources.

---
 plugingui/imagecache.cc | 104 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 104 insertions(+)
 create mode 100644 plugingui/imagecache.cc

(limited to 'plugingui/imagecache.cc')

diff --git a/plugingui/imagecache.cc b/plugingui/imagecache.cc
new file mode 100644
index 0000000..6ce1171
--- /dev/null
+++ b/plugingui/imagecache.cc
@@ -0,0 +1,104 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/***************************************************************************
+ *            imagecache.cc
+ *
+ *  Thu Jun  2 17:12:05 CEST 2016
+ *  Copyright 2016 Bent Bisballe Nyeng
+ *  deva@aasimon.org
+ ****************************************************************************/
+
+/*
+ *  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.
+ */
+#include "imagecache.h"
+
+#include <cassert>
+
+#include "image.h"
+
+namespace GUI
+{
+
+ScopedImageBorrower::ScopedImageBorrower(ImageCache& imageCache,
+                                         const std::string& filename)
+	: imageCache(imageCache)
+	, filename(filename)
+	, image(imageCache.borrow(filename))
+{
+}
+
+ScopedImageBorrower::ScopedImageBorrower(ScopedImageBorrower&& other)
+	: imageCache(other.imageCache)
+	, filename(other.filename)
+	, image(other.image)
+{
+	other.filename.clear();
+}
+
+ScopedImageBorrower::~ScopedImageBorrower()
+{
+	if(!filename.empty())
+	{
+		imageCache.giveBack(filename);
+	}
+}
+
+Image& ScopedImageBorrower::operator*()
+{
+	return image;
+}
+
+Image& ScopedImageBorrower::operator()()
+{
+	return image;
+}
+
+ScopedImageBorrower ImageCache::getImage(const std::string& filename)
+{
+	return ScopedImageBorrower(*this, filename);
+}
+
+Image& ImageCache::borrow(const std::string& filename)
+{
+	auto cacheIterator = imageCache.find(filename);
+	if(cacheIterator == imageCache.end())
+	{
+		Image image(filename);
+		auto insertValue =
+			imageCache.emplace(filename,
+			                   std::move(std::make_pair(0, std::move(image))));
+		cacheIterator = insertValue.first;
+	}
+
+	auto& cacheEntry = cacheIterator->second;
+	++cacheEntry.first;
+	return cacheEntry.second;
+}
+
+void ImageCache::giveBack(const std::string& filename)
+{
+	auto cacheIterator = imageCache.find(filename);
+	assert(cacheIterator != imageCache.end());
+	auto& cacheEntry = cacheIterator->second;
+	--cacheEntry.first;
+	if(cacheEntry.first == 0)
+	{
+		imageCache.erase(cacheIterator);
+	}
+}
+
+} // GUI::
-- 
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