libsolutil: Adding findFilesRecursively() helper to find files recursively.

libsolutil/CommonIO.h

@@ -48,6 +48,46 @@ inline std::ostream& operator<<(std::ostream& os, bytes const& _bytes)
 namespace util
 {
 
+namespace detail
+{
+
+template <typename Predicate>
+struct RecursiveFileCollector
+{
+	Predicate predicate;
+	std::vector<boost::filesystem::path> result {};
+
+	RecursiveFileCollector& operator()(boost::filesystem::path const& _directory)
+	{
+		if (!boost::filesystem::is_directory(_directory))
+			return *this;
+		auto iterator = boost::filesystem::directory_iterator(_directory);
+		auto const iteratorEnd = boost::filesystem::directory_iterator();
+
+		while (iterator != iteratorEnd)
+		{
+			if (boost::filesystem::is_directory(iterator->status()))
+				(*this)(iterator->path());
+
+			if (predicate(iterator->path()))
+				result.push_back(iterator->path());
+
+			++iterator;
+		}
+		return *this;
+	}
+};
+
+template <typename Predicate>
+RecursiveFileCollector(Predicate) -> RecursiveFileCollector<Predicate>;
+}
+
+template <typename Predicate>
+std::vector<boost::filesystem::path> findFilesRecursively(boost::filesystem::path const& _rootDirectory, Predicate _predicate)
+{
+	return detail::RecursiveFileCollector{_predicate}(_rootDirectory).result;
+}
+
 /// Retrieves and returns the contents of the given file as a std::string.
 /// If the file doesn't exist, it will throw a FileNotFound exception.
 /// If the file exists but is not a regular file, it will throw NotAFile exception.