Working on backing files.

Also started a sketches project to illustrate quick ideas.

File.cc

@@ -21,12 +21,13 @@
 /// SOFTWARE.
 ///
 
+#include <filesystem>
 #include "File.h"
 
 
-const std::string &File::Path() const
+const std::string File::Path()
 {
-	return path;
+	return this->path.string();
 }
 
 
@@ -41,3 +42,83 @@ File::File(std::string fPath)
 {
 
 }
+
+OptOutFileStream File::Flush()
+{
+	// Exit early if we shouldn't be writing to the file.
+	if (this->IsReadOnly()) {
+		return std::nullopt;
+	}
+
+	if (!this->Exists()) {
+		if (!this->IsWriteable()) {
+			return std::nullopt;
+		}
+
+		return {new std::ofstream(this->path, this->mode|std::ios::trunc)};
+	}
+
+	return {new std::ofstream(this->path, this->mode)};
+}
+
+
+OptInFileStream
+File::Refresh()
+{
+	if (!this->Exists()) {
+		return std::nullopt;
+	}
+
+	return {new std::ifstream(this->path, this->mode)};
+}
+
+
+size_t
+File::Size()
+{
+	return std::filesystem::file_size(this->path);
+}
+
+
+bool
+File::Exists()
+{
+	return std::filesystem::exists(this->path);
+}
+
+
+static bool
+checkAccess(std::filesystem::path path, std::filesystem::perms mode, bool checkParent)
+{
+	if (!std::filesystem::exists(path) && checkParent) {
+		auto fullPath = std::filesystem::absolute(path);
+		auto parent = fullPath.parent_path();
+		auto dirEnt = std::filesystem::directory_entry(parent);
+		auto perms = dirEnt.status().permissions();
+		return (perms & mode) != std::filesystem::perms::none;
+	}
+
+	return (status(path).permissions() & mode) != std::filesystem::perms::none;
+}
+
+
+bool
+File::IsWriteable()
+{
+	return checkAccess(this->path, std::filesystem::perms::owner_write, true);
+}
+
+
+bool
+File::IsReadable()
+{
+	return checkAccess(this->path, std::filesystem::perms::owner_read, false);
+}
+
+
+bool
+File::IsReadWriteable()
+{
+	auto checkMode = std::filesystem::perms::owner_read | std::filesystem::perms::owner_write;
+	return checkAccess(this->path, checkMode, true);
+}