shellfish/handler/
default.rs

1use std::collections::HashMap;
2
3use yansi::Paint;
4
5use crate::command::CommandType;
6use crate::Command;
7/// A handler lets you change how commands are run. They also let you
8/// change the shell built-ins. A handler takes a Vec<String> as
9/// input, and return a bool. A handler also takes a HashMap<String, Commands>,
10/// so it knows what commands it can run. Likewise, the state is also given.
11///
12/// The bool sent in return is wether or not this command should quit the
13/// shell. For example, in default shellfish, `true` is only every returned
14/// when the commands `quit` or `exit` are given.
15///
16/// For nearly every use case
17/// the default handler should be enough. If in doubt, you can create your
18/// own. I would recommend looking at shellfish's source code for an example
19pub trait Handler<T> {
20    fn handle(
21        &self,
22        args: Vec<String>,
23        commands: &HashMap<&str, Command<T>>,
24        state: &mut T,
25        description: &str,
26    ) -> bool;
27}
28
29/// Shellfish's default handler. This handler is pretty simple, given the
30/// only special options are `help`, `quit` and `exit`.
31#[derive(Default, Copy, Clone, Eq, PartialEq)]
32pub struct DefaultHandler();
33
34impl<T> Handler<T> for DefaultHandler {
35    fn handle(
36        &self,
37        line: Vec<String>,
38        commands: &HashMap<&str, Command<T>>,
39        state: &mut T,
40        description: &str,
41    ) -> bool {
42        if let Some(command) = line.first() {
43            // Add some padding.
44            println!();
45
46            match command.as_str() {
47                "quit" | "exit" => return true,
48                "help" => {
49                    println!("{}", description);
50
51                    // Print information about built-in commands
52                    println!("    help - displays help information.");
53                    println!("    quit - quits the shell.");
54                    println!("    exit - exits the shell.");
55                    for (name, command) in commands {
56                        println!("    {} - {}", name, command.help);
57                    }
58                }
59                _ => {
60                    // Attempt to find the command
61                    let command = commands.get(&*line[0]);
62
63                    // Checks if we got it
64                    match command {
65                        Some(command) => {
66                            if let Err(e) = match command.command {
67                                CommandType::Sync(c) => c(state, line),
68                                #[cfg(feature = "async")]
69                                CommandType::Async(_) => {
70                                    eprintln!("{}", Paint::red("Async commands cannot be run in sync shells."));
71                                    Ok(())
72                                }
73                            } {
74                                eprintln!("{}", Paint::red(&format!("Command exited unsuccessfully:\n{}\n({:?})", &e, &e)))
75                            }
76                        }
77                        None => {
78                            eprintln!(
79                                "{} {}",
80                                Paint::red("Command not found:"),
81                                line[0]
82                            )
83                        }
84                    }
85                }
86            }
87
88            // Padding
89            println!();
90        }
91        false
92    }
93}
shellfish/handler/default.rs

shellfish/handler/
default.rs
