--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/FilesystemWorker.h	Sat Jan 25 21:28:37 2020 +0100
@@ -0,0 +1,116 @@
+/**
+ * Relational pipes
+ * Copyright © 2019 František Kučera (Frantovo.cz, GlobalCode.info)
+ *
+ * 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, version 3 of the License.
+ *
+ * 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, see <http://www.gnu.org/licenses/>.
+ */
+#pragma once
+
+#include <cstdlib>
+#include <iostream>
+#include <sstream>
+#include <string>
+#include <vector>
+#include <map>
+#include <memory>
+#include <algorithm>
+#include <filesystem>
+
+#include <pwd.h>
+#include <grp.h>
+#include <sys/stat.h>
+
+#include <sys/xattr.h>
+
+#include <relpipe/writer/typedefs.h>
+
+#include "Configuration.h"
+#include "AttributeFinder.h"
+#include "FileAttributeFinder.h"
+#include "XattrAttributeFinder.h"
+#include "StreamletAttributeFinder.h"
+
+namespace relpipe {
+namespace in {
+namespace filesystem {
+
+namespace fs = std::filesystem;
+using namespace relpipe::writer;
+
+class FilesystemWorker {
+protected:
+	std::wstring_convert<codecvt_utf8<wchar_t>> convertor; // TODO: support also other encodings.	
+
+	std::map<string_t, std::shared_ptr<AttributeFinder>> createAttributeFinders() {
+		return {
+			{RequestedField::GROUP_FILE, std::make_shared<FileAttributeFinder>()},
+			{RequestedField::GROUP_STREAMLET, std::make_shared<StreamletAttributeFinder>()},
+			{RequestedField::GROUP_XATTR, std::make_shared<XattrAttributeFinder>()}};
+	}
+
+	void reset(std::stringstream& stream) {
+		stream.str("");
+		stream.clear();
+	}
+
+	bool readNext(std::istream& input, std::stringstream& originalName) {
+		for (char ch; input.get(ch);) {
+			if (ch == 0) return true;
+			else originalName << ch;
+		}
+		return originalName.tellp();
+	}
+
+	string_t fetchRelationName(Configuration* configuration) {
+		return configuration->relation.empty() ? L"filesystem" : configuration->relation;
+	}
+
+	void writeHeader(RelationalWriter* writer, std::map<string_t, std::shared_ptr < AttributeFinder>> attributeFinders, string_t relationName, std::vector<RequestedField>* fields, bool writeHeader = true) {
+		std::vector<AttributeMetadata> attributesMetadata;
+		for (RequestedField field : *fields) {
+			std::shared_ptr<AttributeFinder> finder = attributeFinders[field.group];
+			if (finder) for (AttributeMetadata m : finder->toMetadata(writer, relationName, field)) attributesMetadata.push_back(m);
+			else throw RelpipeWriterException(L"Unsupported field group: " + field.group);
+		}
+
+		writer->startRelation(relationName, attributesMetadata, writeHeader);
+	}
+
+	void processSingleFile(std::shared_ptr<RelationalWriter> writer, std::stringstream& originalName, std::map<string_t, std::shared_ptr < AttributeFinder>>&attributeFinders, Configuration& configuration, string_t relationName) {
+		fs::path file(originalName.str().empty() ? "." : originalName.str()); // interpret empty string as current directory (e.g. result of: find -printf '%P\0')
+		bool exists = false;
+
+		try {
+			exists = fs::exists(file);
+		} catch (const fs::filesystem_error& e) {
+			// we probably do not have permissions to given directory → pretend that the file does not exist
+		}
+
+		for (auto& finder : attributeFinders) finder.second->startFile(file, originalName.str(), exists);
+
+		for (RequestedField field : configuration.fields) {
+			std::shared_ptr<AttributeFinder> finder = attributeFinders[field.group]; // should not be nullptr, because already checked while writing the relation metadata
+			finder->writeField(writer.get(), relationName, field);
+		}
+
+		for (auto& finder : attributeFinders) finder.second->endFile();
+	}
+
+public:
+
+	virtual ~FilesystemWorker() = default;
+};
+
+}
+}
+}