CD Command in C command line-CodePudding

I'm trying to make a CD command for a shell I call POSH (Pine's own shell).

If the previous cd command didn't end in a /, it will append the two paths and throw (cd pine then cd src will error because path would be /home/dingus/pinesrc instead of /home/dingus/pine/src).

I know why this happens, but can't seem to fix it.

Here is the source code:

inline void cd(string cmd)
{
    if(cmd.length() < 3) return;
    string arg = cmd.substr(3);
    if(fs::is_directory(fs::status( string(path).append(arg))))
    {
        path.append(arg);
    }
    else cout << "Error: \"" << arg << "\" is not a directory" << endl;
}

CodePudding user response：

string(path).append(arg) is performing string concatenation. You are not appending any of your own slashes between filesystem elements. So, if the path is /home/dingus/, then cd pine would just append pine to the end producing /home/dingus/pine, and then cd src would just append src to the end producing /home/dingus/pinesrc, as you observed.

You would need to do something more like this instead:

string curr_path;

inline void cd(string cmd)
{
    if (cmd.length() < 4) return;
    string arg = cmd.substr(3);
    string new_path = curr_path;
    if ((!new_path.empty()) && (new_path.back() != '\\')) {
        new_path  = '\\';
    }
    new_path  = arg;
    if (fs::is_directory(fs::status(new_path))) {
        curr_path = new_path;
    }
    else {
        cout << "Error: \"" << arg << "\" is not a directory" << endl;
    }
}

However, since you are using the <filesystem> library anyway, you should be using std::filesystem::path (especially since std::filesystem::status() only accepts std::filesystem::path to begin with). Let the library handle any path concatenations for you, eg:

fs::path curr_path;

inline void cd(string cmd)
{
    if (cmd.length() < 4) return;
    string arg = cmd.substr(3);
    fs::path new_path = curr_path / arg;
    if (fs::is_directory(new_path)) {
        curr_path = new_path;
    }
    else {
        cout << "Error: \"" << arg << "\" is not a directory" << endl;
    }
}

std::filesystem::path implements operator/ to insert a slash if one is not already present.