--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/FileAttributeFinder.h	Wed Jan 16 17:23:05 2019 +0100
@@ -0,0 +1,144 @@
+/**
+ * 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, either version 3 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, see <http://www.gnu.org/licenses/>.
+ */
+#pragma once
+
+#include <vector>
+#include <filesystem>
+
+#include <relpipe/writer/typedefs.h>
+#include <relpipe/writer/AttributeMetadata.h>
+#include <relpipe/writer/RelationalWriter.h>
+
+#include "RequestedField.h"
+
+namespace relpipe {
+namespace in {
+namespace filesystem {
+
+namespace fs = std::filesystem;
+using namespace relpipe::writer;
+
+class FileAttributeFinder : public AttributeFinder {
+private:
+	std::wstring_convert<codecvt_utf8<wchar_t>> convertor; // TODO: support also other encodings.
+
+	fs::path currentFile;
+	string_t currentOwner;
+	string_t currentGroup;
+
+	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);
+	}
+public:
+
+	static const string_t FIELD_PATH_ORIGINAL;
+	static const string_t FIELD_NAME;
+	static const string_t FIELD_SIZE;
+	static const string_t FIELD_PATH_ABSOLUTE;
+	static const string_t FIELD_PATH_CANONICAL;
+	static const string_t FIELD_TYPE;
+	static const string_t FIELD_OWNER;
+	static const string_t FIELD_GROUP;
+
+	virtual vector<AttributeMetadata> toMetadata(const RequestedField& field) override {
+		if (field.group == RequestedField::GROUP_FILE) {
+			if (field.name == FIELD_SIZE) return { AttributeMetadata{field.name, TypeId::INTEGER}};
+			else return { AttributeMetadata{field.name, TypeId::STRING}};
+		} else {
+			return {};
+		}
+	}
+
+	void startFile(const fs::path& file) override {
+		currentFile = file;
+	};
+
+	void endFile() override {
+		currentOwner.clear();
+		currentGroup.clear();
+	};
+
+	virtual void writeField(RelationalWriter* writer, const RequestedField& field) override {
+		if (field.group == RequestedField::GROUP_FILE) {
+			if (field.name == FIELD_NAME) {
+				writer->writeAttribute(currentFile.filename().wstring());
+			} else if (field.name == FIELD_PATH_ORIGINAL) {
+				writer->writeAttribute(currentFile.wstring());
+			} else if (field.name == FIELD_PATH_ABSOLUTE) {
+				writer->writeAttribute(fs::absolute(currentFile).wstring());
+			} else if (field.name == FIELD_PATH_CANONICAL) {
+				writer->writeAttribute(fs::canonical(currentFile).wstring());
+			} else if (field.name == FIELD_TYPE) {
+				writer->writeAttribute(getType(currentFile));
+			} else if (field.name == FIELD_SIZE) {
+				integer_t size = fs::is_regular_file(currentFile) ? fs::file_size(currentFile) : 0;
+				writer->writeAttribute(&size, typeid (size));
+			} else if (field.name == FIELD_OWNER) {
+				if (currentOwner.empty()) fetchOwner(currentFile, currentOwner, currentGroup);
+				writer->writeAttribute(currentOwner);
+			} else if (field.name == FIELD_GROUP) {
+				if (currentOwner.empty()) fetchOwner(currentFile, currentOwner, currentGroup);
+				writer->writeAttribute(currentGroup);
+			} else {
+				// TODO: should not happend; check supported attributes in toMetadata()?
+				writer->writeAttribute(L"");
+			}
+		}
+	}
+
+	virtual ~FileAttributeFinder() override {
+	}
+};
+
+const string_t FileAttributeFinder::FIELD_PATH_ORIGINAL = L"path";
+const string_t FileAttributeFinder::FIELD_NAME = L"name";
+const string_t FileAttributeFinder::FIELD_SIZE = L"size";
+const string_t FileAttributeFinder::FIELD_PATH_ABSOLUTE = L"path_absolute";
+const string_t FileAttributeFinder::FIELD_PATH_CANONICAL = L"path_canonical";
+const string_t FileAttributeFinder::FIELD_TYPE = L"type";
+const string_t FileAttributeFinder::FIELD_OWNER = L"owner";
+const string_t FileAttributeFinder::FIELD_GROUP = L"group";
+
+}
+}
+}