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use error::*;
#[cfg(windows)]
use helper::has_executable_extension;
use std::env;
use std::ffi::OsStr;
#[cfg(windows)]
use std::ffi::OsString;
use std::iter;
use std::path::{Path, PathBuf};
pub trait Checker {
fn is_valid(&self, path: &Path) -> bool;
}
trait PathExt {
fn has_separator(&self) -> bool;
fn to_absolute<P>(self, cwd: P) -> PathBuf
where
P: AsRef<Path>;
}
impl PathExt for PathBuf {
fn has_separator(&self) -> bool {
self.components().count() > 1
}
fn to_absolute<P>(self, cwd: P) -> PathBuf
where
P: AsRef<Path>,
{
if self.is_absolute() {
self
} else {
let mut new_path = PathBuf::from(cwd.as_ref());
new_path.push(self);
new_path
}
}
}
pub struct Finder;
impl Finder {
pub fn new() -> Finder {
Finder
}
pub fn find<T, U, V>(
&self,
binary_name: T,
paths: Option<U>,
cwd: V,
binary_checker: &dyn Checker,
) -> Result<PathBuf>
where
T: AsRef<OsStr>,
U: AsRef<OsStr>,
V: AsRef<Path>,
{
let path = PathBuf::from(&binary_name);
let binary_path_candidates: Box<dyn Iterator<Item = _>> = if path.has_separator() {
// Search binary in cwd if the path have a path separator.
let candidates = Self::cwd_search_candidates(path, cwd).into_iter();
Box::new(candidates)
} else {
// Search binary in PATHs(defined in environment variable).
let p = paths.ok_or(Error::CannotFindBinaryPath)?;
let paths: Vec<_> = env::split_paths(&p).collect();
let candidates = Self::path_search_candidates(path, paths).into_iter();
Box::new(candidates)
};
for p in binary_path_candidates {
// find a valid binary
if binary_checker.is_valid(&p) {
return Ok(p);
}
}
// can't find any binary
Err(Error::CannotFindBinaryPath)
}
fn cwd_search_candidates<C>(binary_name: PathBuf, cwd: C) -> impl IntoIterator<Item = PathBuf>
where
C: AsRef<Path>,
{
let path = binary_name.to_absolute(cwd);
Self::append_extension(iter::once(path))
}
fn path_search_candidates<P>(
binary_name: PathBuf,
paths: P,
) -> impl IntoIterator<Item = PathBuf>
where
P: IntoIterator<Item = PathBuf>,
{
let new_paths = paths.into_iter().map(move |p| p.join(binary_name.clone()));
Self::append_extension(new_paths)
}
#[cfg(unix)]
fn append_extension<P>(paths: P) -> impl IntoIterator<Item = PathBuf>
where
P: IntoIterator<Item = PathBuf>,
{
paths
}
#[cfg(windows)]
fn append_extension<P>(paths: P) -> impl IntoIterator<Item = PathBuf>
where
P: IntoIterator<Item = PathBuf>,
{
// Read PATHEXT env variable and split it into vector of String
let path_exts =
env::var_os("PATHEXT").unwrap_or(OsString::from(env::consts::EXE_EXTENSION));
let exe_extension_vec = env::split_paths(&path_exts)
.filter_map(|e| e.to_str().map(|e| e.to_owned()))
.collect::<Vec<_>>();
paths
.into_iter()
.flat_map(move |p| -> Box<dyn Iterator<Item = _>> {
// Check if path already have executable extension
if has_executable_extension(&p, &exe_extension_vec) {
Box::new(iter::once(p))
} else {
// Appended paths with windows executable extensions.
// e.g. path `c:/windows/bin` will expend to:
// c:/windows/bin.COM
// c:/windows/bin.EXE
// c:/windows/bin.CMD
// ...
let ps = exe_extension_vec.clone().into_iter().map(move |e| {
// Append the extension.
let mut p = p.clone().to_path_buf().into_os_string();
p.push(e);
PathBuf::from(p)
});
Box::new(ps)
}
})
}
}
|
