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use crate::prelude::*;
use std::collections::HashMap;
use std::collections::HashSet;
use std::io;
use std::io::prelude::*;
use std::os::unix::fs::PermissionsExt;
#[macro_use] extern crate lalrpop_util;
lalrpop_mod!(pub commandline);
pub mod error;
pub mod path;
pub mod prelude;
pub mod result;
pub enum Input {
String(String),
End,
}
fn main() -> Result<()> {
std::process::exit(match repl() {
Ok(()) => 0,
Err(ref e) => {
eprintln!("{}", e);
1
}
})
}
fn repl() -> Result<()> {
println!("Hello, terminal!");
loop {
prompt()?;
let input = read()?;
match input {
Input::String(string) => execute(&string)?,
Input::End => break,
}
}
Ok(())
}
fn prompt() -> Result<()> {
print!("$ ");
io::stdout().flush()?;
Ok(())
}
fn read() -> Result<Input> {
let mut input = String::new();
let n_bytes = io::stdin().read_line(&mut input)?;
if n_bytes == 0 {
Ok(Input::End)
} else {
Ok(Input::String(input))
}
}
fn execute(input: &str) -> Result<()> {
let invocation = commandline::InvocationParser::new().parse(input)?;
match invocation.as_slice() {
["environment", ..] => {
let environment = read_environment()?;
println!("{:?}", environment);
}
["which", command_name, ..] => {
match find_executable_path(command_name)? {
Some(executable_path) => {
println!("{}", executable_path);
}
None => {
println!("Command not found: {}", command_name);
}
};
},
[command_name, ..] => {
match find_executable_path(command_name)? {
Some(executable_path) => {
println!("{}", executable_path);
}
None => {
println!("Command not found: {}", command_name);
}
};
},
_ => {
println!("invocation '{:?}'", invocation);
}
}
Ok(())
}
fn read_environment() -> Result<HashMap<String,String>> {
Ok(std::env::vars().collect())
}
fn get_environment(variable_name: &str) -> Result<Option<String>> {
Ok(std::env::vars()
.find(|(key, _)| key == variable_name)
.map(|(_, value)| value))
}
fn get_search_paths() -> Result<Vec<path::AbsoluteDirectoryPath>> {
let paths = get_environment("PATH")?.unwrap_or_default();
let paths = path::parse_path_list(&paths)?;
let mut result = Vec::new();
let mut seen = HashSet::new();
for path in paths {
if seen.contains(&path) {
continue;
}
seen.insert(path.clone());
result.push(path);
}
Ok(result)
}
fn find_executable_path(command_name: &str)
-> Result<Option<path::AbsoluteFilePath>>
{
let file_name: path::FileName = command_name.parse()?;
let search_paths = get_search_paths()?;
let mut executable_path: Option<path::AbsoluteFilePath> = None;
for search_path in &search_paths {
let candidate_path = search_path.concat_file_name(&file_name);
match candidate_path.to_sys_path().metadata() {
Ok(metadata) => {
if metadata.is_file()
&& metadata.permissions().mode() & 0o111 != 0
{
executable_path = Some(candidate_path);
break;
}
},
Err(_) => { },
}
}
Ok(executable_path)
}
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