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use std::fmt::{self, Display};
use nix::sched::CloneFlags;
use crate::Command;
/// This is a builder for various settings of how command may be printed
///
/// Use `format!("{}", cmd.display(style))` to actually print a command.
#[derive(Clone, Debug)]
pub struct Style {
cmd_only: bool,
print_env: bool,
show_path: bool,
}
/// A temporary value returned from `Command::display` for the sole purpose
/// of being `Display`'ed.
pub struct Printer<'a>(&'a Command, &'a Style);
impl Style {
/// Create a new style object that matches to how `fmt::Debug` works for
/// the command
pub fn debug() -> Style {
Style {
cmd_only: false,
print_env: true,
show_path: true,
}
}
/// Create a simple clean user-friendly display of the command
///
/// Note: this kind of pretty-printing omit many important parts of command
/// and may be ambiguous.
pub fn short() -> Style {
Style {
cmd_only: true,
print_env: false,
show_path: false,
}
}
/// Toggle printing of environment
///
/// When `false` is passed we only show `environ[12]`, i.e. a number of
/// environment variables. Default is `true` for `Style::debug`
/// constructor.
///
/// This method does nothing when using `Style::short` construtor
pub fn env(mut self, enable: bool) -> Style {
self.print_env = enable;
self
}
/// Toggle printing of full path to the executable
///
/// By default we don't print full executable path in `Style::short` mode.
///
/// Note: if this flag is disabled (default) we only show a name from
/// `arg0`, instead of executable path. When flag is
/// enabled, the `arg0` is shown alongside with executable path in
/// parethesis if the values differ.
///
/// This method does nothing when using `Style::debug` constructor
pub fn path(mut self, enable: bool) -> Style {
self.show_path = enable;
self
}
}
impl<'a> fmt::Display for Printer<'a> {
fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
let Printer(cmd, opt) = *self;
if opt.cmd_only {
if opt.show_path {
write!(fmt, "{:?}", cmd.filename)?;
if cmd.args[0] != cmd.filename {
write!(fmt, " ({:?})", &cmd.args[0])?;
}
} else {
let path = if cmd.args[0] != cmd.filename {
&cmd.args[0]
} else {
&cmd.filename
};
let last_slash = path.as_bytes().iter()
.rposition(|&x| x == b'/');
if let Some(off) = last_slash {
write!(fmt, "{:?}",
&String::from_utf8_lossy(&path.as_bytes()[off+1..]))?;
} else {
write!(fmt, "{:?}", path)?;
}
}
for arg in cmd.args[1..].iter() {
write!(fmt, " {:?}", arg)?;
}
} else {
write!(fmt, "<Command {:?}", cmd.filename)?;
if cmd.args[0] != cmd.filename {
write!(fmt, " ({:?})", &cmd.args[0])?;
}
for arg in cmd.args[1..].iter() {
write!(fmt, " {:?}", arg)?;
}
if opt.print_env {
if let Some(ref env) = cmd.environ {
write!(fmt, "; environ: {{")?;
for (ref k, ref v) in env.iter() {
write!(fmt, "{:?}={:?},", k, v)?;
}
write!(fmt, "}}")?;
}
} else {
if let Some(ref env) = cmd.environ {
write!(fmt, "; environ[{}]", env.len())?;
}
}
if let Some(ref dir) = cmd.chroot_dir {
write!(fmt, "; chroot={:?}", dir)?;
}
if let Some((ref new, ref old, unmount)) = cmd.pivot_root {
write!(fmt, "; pivot_root=({:?};{:?};{})", new, old, unmount)?;
}
if cmd.config.namespaces != CloneFlags::empty() {
// TODO(tailhook)
}
if let Some(ref dir) = cmd.config.work_dir {
write!(fmt, "; work-dir={:?}", dir)?;
}
if let Some((ref uidm, ref gidm)) = cmd.config.id_maps {
write!(fmt, "; uid_map={:?}", uidm)?;
write!(fmt, "; gid_map={:?}", gidm)?;
}
if let Some(ref uid) = cmd.config.uid {
write!(fmt, "; uid={}", uid)?;
}
if let Some(ref gid) = cmd.config.gid {
write!(fmt, "; gid={}", gid)?;
}
if let Some(ref gids) = cmd.config.supplementary_gids {
write!(fmt, "; gids={:?}", gids)?;
}
// TODO(tailhook) stdio, sigchld, death_sig,
// sigmask, id-map-commands
write!(fmt, ">")?
}
Ok(())
}
}
impl Command {
/// Returns the object that implements Display
pub fn display<'a>(&'a self, style: &'a Style) -> Printer<'a> {
Printer(self, style)
}
}
impl fmt::Debug for Command {
fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
Printer(self, &Style::debug()).fmt(fmt)
}
}
#[cfg(test)]
mod test {
use crate::{Command, Style};
#[test]
fn test_debug() {
let mut cmd = Command::new("/bin/hello");
cmd.env_clear();
cmd.env("A", "B");
assert_eq!(&format!("{:?}", cmd),
r#"<Command "/bin/hello"; environ: {"A"="B",}>"#);
}
#[test]
fn test_comprehensive() {
let mut cmd = Command::new("/bin/hello");
cmd.env_clear();
cmd.env("A", "B");
assert_eq!(&format!("{}", cmd.display(&Style::debug())),
r#"<Command "/bin/hello"; environ: {"A"="B",}>"#);
}
#[test]
fn test_pretty() {
let mut cmd = Command::new("/bin/hello");
cmd.env_clear();
cmd.arg("world!");
assert_eq!(&format!("{}", cmd.display(&Style::short())),
r#""hello" "world!""#);
}
#[test]
fn test_no_env() {
let mut cmd = Command::new("/bin/hello");
cmd.env_clear();
cmd.env("A", "B");
assert_eq!(&format!("{}", cmd.display(&Style::debug().env(false))),
r#"<Command "/bin/hello"; environ[1]>"#);
}
}