Cache textures by checksum

src/filecache.cpp

@@ -0,0 +1,117 @@
+/*
+Minetest-c55
+Copyright (C) 2010 celeron55, Perttu Ahola <celeron55@gmail.com>
+Copyright (C) 2012 Jonathan Neuschäfer <j.neuschaefer@gmx.net>
+
+This program 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 2 of the License, or
+(at your option) any later version.
+
+This program 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 this program; if not, write to the Free Software Foundation, Inc.,
+51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+*/
+
+#include "filecache.h"
+#include "clientserver.h"
+#include "log.h"
+#include "filesys.h"
+#include "utility.h"
+#include "hex.h"
+
+#include <string>
+#include <iostream>
+
+bool FileCache::loadByPath(const std::string &name, std::ostream &os,
+		const std::string &path)
+{
+	std::ifstream fis(path.c_str(), std::ios_base::binary);
+
+	if(!fis.good()){
+		infostream<<"FileCache: File not found in cache: "
+			<<name << " expected it at: "<<path<<std::endl;
+		return false;
+	}
+
+	bool bad = false;
+	for(;;){
+		char buf[1024];
+		fis.read(buf, 1024);
+		std::streamsize len = fis.gcount();
+		os.write(buf, len);
+		if(fis.eof())
+			break;
+		if(!fis.good()){
+			bad = true;
+			break;
+		}
+	}
+	if(bad){
+		infostream<<"FileCache: Failed to read file from cache: \""
+			<<path<<"\""<<std::endl;
+	}
+
+	return !bad;
+}
+
+bool FileCache::updateByPath(const std::string &name, const std::string &data,
+		const std::string &path)
+{
+	std::ofstream file(path.c_str(), std::ios_base::binary |
+			std::ios_base::trunc);
+
+	if(!file.good())
+	{
+		errorstream<<"FileCache: Can't write to file at "
+			<<path<<std::endl;
+		return false;
+	}
+
+	file.write(data.c_str(), data.length());
+	file.close();
+
+	return !file.fail();
+}
+
+bool FileCache::loadByName(const std::string &name, std::ostream &os)
+{
+	std::string path = m_dir + DIR_DELIM + name;
+	return loadByPath(name, os, path);
+}
+
+
+bool FileCache::updateByName(const std::string &name, const std::string &data)
+{
+	std::string path = m_dir + DIR_DELIM + name;
+	return updateByPath(name, data, path);
+}
+
+std::string FileCache::getPathFromChecksum(const std::string &name,
+		const std::string &checksum)
+{
+	std::string checksum_hex = hex_encode(checksum.c_str(), checksum.length());
+	size_t dot = name.find_last_of('.');;
+	std::string ext = (dot == std::string::npos)? "" :
+		name.substr(dot, std::string::npos);
+	return m_dir + DIR_DELIM + checksum_hex + ext;
+}
+
+bool FileCache::loadByChecksum(const std::string &name, std::ostream &os,
+		const std::string &checksum)
+{
+	std::string path = getPathFromChecksum(name, checksum);
+	return loadByPath(name, os, path);
+}
+
+bool FileCache::updateByChecksum(const std::string &name,
+		const std::string &data, const std::string &checksum)
+{
+	std::string path = getPathFromChecksum(name, checksum);
+	return updateByPath(name, data, path);
+}