Module crosvm_direct::crosvm::argument

Expand description

Handles argument parsing.

Example

let arguments = &[
    Argument::positional("FILES", "files to operate on"),
    Argument::short_value('p', "program", "PROGRAM", "Program to apply to each file"),
    Argument::short_value('c', "cpus", "N", "Number of CPUs to use. (default: 1)"),
    Argument::flag("unmount", "Unmount the root"),
    Argument::short_flag('h', "help", "Print help message."),
];

let match_res = set_arguments(args, arguments, |name, value| {
    match name {
        "" => println!("positional arg! {}", value.unwrap()),
        "program" => println!("gonna use program {}", value.unwrap()),
        "cpus" => {
            let v: u32 = value.unwrap().parse().map_err(|_| {
                Error::InvalidValue {
                    value: value.unwrap().to_owned(),
                    expected: String::from("this value for `cpus` needs to be integer"),
                }
            })?;
        }
        "unmount" => println!("gonna unmount"),
        "help" => return Err(Error::PrintHelp),
        _ => unreachable!(),
    }
    unreachable!();
});

match match_res {
    Ok(_) => println!("running with settings"),
    Err(Error::PrintHelp) => print_help("best_program", "FILES", arguments),
    Err(e) => println!("{}", e),
}

Structs

Argument

Information about an argument expected from the command line.

KeyValuePair

Enums

ArgumentValueMode

Error

An error with argument parsing.

Functions

get_columns 🔒

Get the number of columns on a display, with a reasonable default.

get_leading_part 🔒

Obtain the leading part of the help message. The output is later processed to reflow. Depending on how short this, newline is used.

parse_arguments 🔒

parse_hex_or_decimal

parse_key_value_options

Parse a string of delimiter-separated key-value options. This is intended to simplify parsing of command-line options that take a bunch of parameters encoded into the argument, e.g. for setting up an emulated hardware device. Returns an Iterator of KeyValuePair, which provides convenience functions to parse numeric values and performs appropriate error handling.

print_help

Prints command line usage information to stdout.

reflow 🔒

Poor man’s reflowing function for string. This function will unsplit the lines, an empty line splits a paragraph.

set_arguments

Parses the given args against the list of know arguments arg_list and calls f with each present argument and value if required.

Type Definitions

Result