Refactor xpath query into a separate function.

CMakeLists.txt

@@ -36,6 +36,7 @@ add_executable(${PROJECT_NAME}
 	src/htmlretrieve.cpp
 	src/commandline.cpp
 	src/scraplang/scraplang.cpp
+	src/xpath.cpp
 )
 
 if (BUILD_SHARED_TIDY)

src/main.cpp

@@ -1,9 +1,8 @@
 #include "htmlretrieve.hpp"
 #include "commandline.hpp"
+#include "xpath.hpp"
 #include <iostream>
 #include <string>
-#include <pugixml.hpp>
-#include <sstream>
 #include <fstream>
 #include <utility>
 #include <ciso646>
@@ -12,9 +11,6 @@
 #include <stdexcept>
 
 namespace {
-	typedef std::pair<int, int> LineColType;
-
-	LineColType line_col_from_offset ( ptrdiff_t parOffset, const std::string& parData );
 	void dump_string ( const std::string& parPathDest, const std::string& parData );
 } //unnamed namespace
 
@@ -61,50 +57,24 @@ int main (int argc, char* argv[]) {
 		dump_string(vm["dump"].as<std::string>(), html);
 	}
 
-	{
-		pugi::xml_document doc;
-		std::istringstream iss(html);
-		pugi::xml_parse_result result(doc.load(iss));
-		if (not result) {
-			auto line_col = line_col_from_offset(result.offset, html);
-			std::cerr << "Error parsing the source XML at line " <<
-				line_col.first << " col " << line_col.second << ":\n" <<
-				result.description() << std::endl;
-			return 1;
-		}
-
-		pugi::xpath_node_set xpathRes = doc.select_nodes(xpath.c_str());
-		for (pugi::xpath_node_set::const_iterator itFind(xpathRes.begin()), itFindEND(xpathRes.end()); itFind != itFindEND; ++itFind) {
-			const pugi::xpath_node& node = *itFind;
-			if (node.node()) {
-				std::cout << node.node().name() << ": " << node.node().value() << "\n";
-			}
-			else if (node.attribute()) {
-				std::cout << node.attribute().name() << ": " << node.attribute().value() << "\n";
-			}
+	try {
+		std::vector<std::string> queries;
+		queries.reserve(1);
+		queries.push_back(std::move(xpath));
+		auto results = duck::xpath_query(html, queries);
+		for (const auto& lst : results[0]) {
+			std::cout << lst.first << ": " << lst.second << '\n';
 		}
 	}
+	catch (const duck::ParseError& err) {
+		std::cerr << err.what() << std::endl;
+		return 1;
+	}
+
 	return 0;
 }
 
 namespace {
-	LineColType line_col_from_offset (ptrdiff_t parOffset, const std::string& parData) {
-		size_t index = 0;
-		int line = 1;
-		int chara = 1;
-		while (parOffset and index < parData.size()) {
-			if (parData[index] == '\n') {
-				chara = 1;
-				++line;
-			}
-			else {
-				++chara;
-			}
-			++index;
-			--parOffset;
-		}
-		return std::make_pair(line, chara);
-	}
 
 	void dump_string (const std::string& parPathDest, const std::string& parData) {
 		std::unique_ptr<std::ofstream> ofs;

src/xpath.cpp

@@ -0,0 +1,75 @@
+#include "xpath.hpp"
+#include <pugixml.hpp>
+#include <sstream>
+#include <stdexcept>
+#include <algorithm>
+
+namespace duck {
+	namespace {
+		typedef std::pair<int, int> LineColType;
+
+		LineColType line_col_from_offset (ptrdiff_t parOffset, const std::string& parData) {
+			size_t index = 0;
+			int line = 1;
+			int chara = 1;
+			while (parOffset and index < parData.size()) {
+				if (parData[index] == '\n') {
+					chara = 1;
+					++line;
+				}
+				else {
+					++chara;
+				}
+				++index;
+				--parOffset;
+			}
+			return std::make_pair(line, chara);
+		}
+	} //unnamed namespace
+
+	XPathBatchResults xpath_query (const std::string& parXML, const std::vector<std::string>& parQueries) {
+		pugi::xml_document doc;
+		std::istringstream iss(parXML);
+		pugi::xml_parse_result result(doc.load(iss));
+		if (not result) {
+			auto line_col = line_col_from_offset(result.offset, parXML);
+			throw ParseError(line_col.first, line_col.second, result.description());
+		}
+
+		XPathBatchResults retval;
+		for (const auto& xpath : parQueries) {
+			pugi::xpath_node_set xpathRes = doc.select_nodes(xpath.c_str());
+			std::vector<std::pair<std::string, std::string>> new_lst;
+			for (pugi::xpath_node_set::const_iterator itFind(xpathRes.begin()), itFindEND(xpathRes.end()); itFind != itFindEND; ++itFind) {
+				const pugi::xpath_node& node = *itFind;
+				std::pair<std::string, std::string> new_itm;
+				if (node.node()) {
+					new_itm.first = std::string(node.node().name());
+					new_itm.second = std::string(node.node().value());
+				}
+				else if (node.attribute()) {
+					new_itm.first = std::string(node.attribute().name());
+					new_itm.second = std::string(node.attribute().value());
+				}
+				new_lst.push_back(std::move(new_itm));
+			}
+			retval.push_back(std::move(new_lst));
+		}
+		return std::move(retval);
+	}
+
+	ParseError::ParseError (int parLine, int parColumn, std::string parMessage) {
+		std::ostringstream oss;
+		oss << "Error parsing the source XML at line " <<
+			parLine << " col " << parColumn << ":\n" <<
+			parMessage << std::endl;
+		auto msg = oss.str();
+		m_msg.resize(msg.size() + 1);
+		std::copy(msg.begin(), msg.end(), m_msg.begin());
+		m_msg[m_msg.size() - 1] = '\0';
+	}
+
+	const char* ParseError::what() const noexcept {
+		return m_msg.data();
+	}
+} //namespace duck

src/xpath.hpp

@@ -0,0 +1,23 @@
+#ifndef id21E0A6F345D24C5D83D3B1F74EC810F7
+#define id21E0A6F345D24C5D83D3B1F74EC810F7
+
+#include <string>
+#include <vector>
+#include <exception>
+#include <utility>
+
+namespace duck {
+	typedef std::vector<std::vector<std::pair<std::string, std::string>>> XPathBatchResults;
+
+	class ParseError : public std::exception {
+	public:
+		ParseError ( int parLine, int parColumn, std::string parMessage );
+		virtual const char* what ( void ) const noexcept;
+	private:
+		std::vector<char> m_msg;
+	};
+
+	XPathBatchResults xpath_query ( const std::string& parXML, const std::vector<std::string>& parQueries );
+} //namespace duck
+
+#endif