--- a/src/FilesystemCommand.h	Sat Jan 12 19:29:49 2019 +0100
+++ b/src/FilesystemCommand.h	Sun Jan 13 03:13:07 2019 +0100
@@ -21,7 +21,15 @@
 #include <iostream>
 #include <string>
 #include <vector>
+#include <array>
 #include <algorithm>
+#include <filesystem>
+
+#include <pwd.h>
+#include <grp.h>
+#include <sys/stat.h>
+
+#include <sys/xattr.h>
 
 #include <relpipe/writer/typedefs.h>
 
@@ -29,25 +37,146 @@
 namespace in {
 namespace filesystem {
 
+namespace fs = std::filesystem;
+using namespace relpipe::writer;
+
 class FilesystemCommand {
+	std::wstring_convert<codecvt_utf8<wchar_t>> convertor; // TODO: support also other encodings.
+
+	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 getType(const fs::path& file) {
+		// TODO: Use whole words? (letters are compatible with find -type)
+		if (fs::is_regular_file(file)) return L"f";
+		else if (fs::is_symlink(file)) return L"l"; // symlinks to directories are both symlinks and directories
+		else if (fs::is_directory(file)) return L"d";
+		else if (fs::is_fifo(file)) return L"p";
+		else if (fs::is_socket(file)) return L"s";
+		else if (fs::is_block_file(file)) return L"b";
+		else if (fs::is_character_file(file)) return L"c";
+		else return L"o";
+	}
+
+	void fetchOwner(const fs::path& file, string_t& owner, string_t& group) {
+		// TODO: throw exception on error
+		// TODO: get user and group in C++ way?
+		struct stat info;
+		stat(file.c_str(), &info);
+		/**
+		 * The return value may point to a static area, and may  be
+		 * overwritten  by  subsequent calls to getpwent(3), getpw‐
+		 * nam(), or getpwuid().  (Do not pass the returned pointer
+		 * to free(3).)
+		 */
+		struct passwd* pw = getpwuid(info.st_uid);
+		struct group* gr = getgrgid(info.st_gid);
+		owner = convertor.from_bytes(pw->pw_name);
+		group = convertor.from_bytes(gr->gr_name);
+	}
+
+	string_t getXattr(const fs::path& file, const string_t& attributeName) {
+		// TODO: review, test on multiple platforms
+		ssize_t length = getxattr(file.c_str(), convertor.to_bytes(attributeName).c_str(), nullptr, 0);
+		if (length > 0) {
+			std::vector<char> buffer(length + 1);
+			getxattr(file.c_str(), convertor.to_bytes(attributeName).c_str(), buffer.data(), length);
+			return convertor.from_bytes(buffer.data());
+		} else {
+			return L"";
+		}
+	}
+
 public:
 
 	void process(std::istream& input, std::ostream& output) {
-		using namespace relpipe::writer;
 		std::shared_ptr<RelationalWriter> writer(Factory::create(output));
 
-		// TODO: remove demo
-		// Various data types passed as strings
-		writer->startRelation(L"filesystem",{
-			{L"s", TypeId::STRING},
-			{L"i", TypeId::INTEGER},
-			{L"b", TypeId::BOOLEAN}
-		}, true);
+		// TODO: redesign: parametrized from CLI + groups of information fetched together and used for multiple attributes
+		bool enableName = true;
+		bool enableExists = false;
+		bool enableNameAbsolute = false;
+		bool enableNameCanonical = false;
+		bool enableType = true;
+		bool enableSize = true;
+		bool enableOwner = true;
+		bool enableGroup = true;
+		bool enableXattrUrl = true; // just a demo
+
+		std::vector<AttributeMetadata> attributesMetadata;
+		if (enableName) attributesMetadata.push_back({L"name", TypeId::STRING});
+		if (enableExists) attributesMetadata.push_back({L"exists", TypeId::BOOLEAN});
+		if (enableNameAbsolute) attributesMetadata.push_back({L"name_absolute", TypeId::STRING});
+		if (enableNameCanonical) attributesMetadata.push_back({L"name_canonical", TypeId::STRING});
+		if (enableType) attributesMetadata.push_back({L"type", TypeId::STRING});
+		if (enableSize) attributesMetadata.push_back({L"size", TypeId::INTEGER});
+		if (enableOwner) attributesMetadata.push_back({L"owner", TypeId::STRING});
+		if (enableGroup) attributesMetadata.push_back({L"group", TypeId::STRING});
+		if (enableXattrUrl) attributesMetadata.push_back({L"xattr_url", TypeId::STRING});
+
+		writer->startRelation(L"filesystem", attributesMetadata, true);
+
+		for (std::stringstream originalName; readNext(input, originalName); reset(originalName)) {
+			if (enableName) writer->writeAttribute(convertor.from_bytes(originalName.str()));
+			fs::path file(originalName.str());
+			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
+			}
 
-		writer->writeAttribute(L"a");
-		writer->writeAttribute(L"1");
-		writer->writeAttribute(L"true");
-		
+			if (exists) {
+				if (enableExists) writer->writeAttribute(L"true");
+				if (enableNameAbsolute) writer->writeAttribute(fs::absolute(file).wstring());
+				if (enableNameCanonical) writer->writeAttribute(fs::canonical(file).wstring());
+				if (enableType) writer->writeAttribute(getType(file));
+				if (enableSize) {
+					integer_t size = fs::is_regular_file(file) ? fs::file_size(file) : 0;
+					writer->writeAttribute(&size, typeid (size));
+				}
+
+				if (enableOwner || enableGroup) {
+					string_t owner;
+					string_t group;
+					fetchOwner(file, owner, group);
+
+					if (enableOwner) writer->writeAttribute(owner);
+					if (enableGroup) writer->writeAttribute(group);
+				}
+
+				if (enableXattrUrl) writer->writeAttribute(getXattr(file, L"user.xdg.origin.url"));
+
+			} else {
+				// Only original name was written → write remaining attributes
+				// TODO: null values (requires adding null support to the format specification)
+				for (int i = 1; i < attributesMetadata.size(); i++) {
+					switch (attributesMetadata[i].typeId) {
+						case TypeId::BOOLEAN: writer->writeAttribute(L"false");
+							break;
+						case TypeId::INTEGER: writer->writeAttribute(L"0");
+							break;
+						case TypeId::STRING: writer->writeAttribute(L"");
+							break;
+						default:
+							throw RelpipeWriterException(L"Unsupported data type.");
+
+					}
+				}
+			}
+		}
+
 	}
 };