XDG-FHS_clatexmath.cpp

#include <filesystem>
#include <string>
#include <queue>
#include <stdio.h>
#include <sstream>

using namespace std;
namespace fs = filesystem;

string queryRootPath(string custom_path) {
	queue<string> paths;
	paths.push(custom_path);

	// checks if XDG_DATA_HOME exists. If it does, it pushes it to potential paths.
	char* userdata = getenv("XDG_DATA_HOME");
	if (userdata != NULL && userdata != "") {
		paths.push(string(userdata));
	}
	delete userdata;

	// checks if XDG_DATA_DIRS is set. If it is, it splits XDG_DATA_DIRS at : and pushes each part of it to potential paths.
	char* xdg = getenv("XDG_DATA_DIRS");
	if (xdg != NULL && xdg != "") {
		stringstream xdg_paths(xdg);
		string xdg_path;
		while (getline(xdg_paths, xdg_path, ':')) {
			paths.push(xdg_path);
		}
	}

	// checks if HOME env var is unset. if it isn't it pushes ~/.local/share/clatexmath to potential paths.
	char* home = getenv("HOME");
	if (home != NULL && home != "") {
		char* userdata_fallback;
		asprintf(&userdata_fallback, "%s/.local/share/clatexmath/", home);
		paths.push(string(userdata_fallback));
		delete userdata_fallback;
	}
	paths.push("/usr/share/clatexmath/");
	paths.push("/usr/local/share/clatexmath/");
	
	// goes through the list of potential paths. if it finds a path that contains .clatexmath-res_root, it returns it. Otherwise I'll throw an error.
	while (paths.size() > 0) {
		fs::path p = paths.front();
		p.append(".clatexmath-res_root");
		if (fs::exists(p)) {
			p.remove_filename();
			return p.u8string();
		}
		paths.pop();
	}
	throw "cLaTeXMath resource path was not found";
}

int main(int argc, char** argv) {
	string path = queryRootPath("res/");
	printf("Found path: %s", path.c_str());
	return 0;
}