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/*
* meli - lib.rs
*
* Copyright 2017 Manos Pitsidianakis
*
* This file is part of meli.
*
* meli is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* meli is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with meli. If not, see <http://www.gnu.org/licenses/>.
*/
//! A `ShellExpandTrait` to expand paths like a shell.
use std::{
ffi::OsStr,
os::unix::ffi::OsStrExt,
path::{Path, PathBuf},
};
use smallvec::SmallVec;
// [ref:needs_dev_doc]: ShellExpandTrait
// [ref:needs_unit_test]: ShellExpandTrait
pub trait ShellExpandTrait {
// [ref:needs_dev_doc]
fn expand(&self) -> PathBuf;
// [ref:needs_dev_doc]
fn complete(&self, force: bool) -> SmallVec<[String; 128]>;
}
impl ShellExpandTrait for Path {
fn expand(&self) -> PathBuf {
// [ref:TODO]: ShellExpandTrait: add support for parameters in braces ${ }
// https://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#tag_18_06_02
let mut ret = PathBuf::new();
for c in self.components() {
let c_to_str = c.as_os_str();
match c_to_str {
tilde if tilde == "~" => {
if let Ok(home_dir) = std::env::var("HOME") {
ret.push(home_dir)
} else {
// POSIX says that if HOME is unset, the results of tilde expansion is
// unspecified.
// https://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#tag_18_06_01
// Abort expansion.
return self.to_path_buf();
}
}
var if var.to_string_lossy().starts_with('$') => {
let var = var.to_string_lossy();
let env_name = var.split_at(1).1;
if env_name.chars().all(char::is_uppercase) {
ret.push(std::env::var(env_name).unwrap_or_default());
} else {
ret.push(c);
}
}
_ => {
ret.push(c);
}
}
}
ret
}
#[cfg(target_os = "linux")]
fn complete(&self, force: bool) -> SmallVec<[String; 128]> {
use std::os::unix::io::AsRawFd;
use libc::dirent64;
use nix::fcntl::OFlag;
const BUF_SIZE: ::libc::size_t = 8 << 10;
let (prefix, _match) = if self.as_os_str().as_bytes().ends_with(b"/.") {
(self.components().as_path(), OsStr::from_bytes(b"."))
} else if self.exists() && (!force || self.as_os_str().as_bytes().ends_with(b"/")) {
return SmallVec::new();
} else {
let last_component = self
.components()
.last()
.map(|c| c.as_os_str())
.unwrap_or_else(|| OsStr::from_bytes(b""));
let prefix = if let Some(p) = self.parent() {
p
} else {
return SmallVec::new();
};
(prefix, last_component)
};
let dir = match ::nix::dir::Dir::openat(
::libc::AT_FDCWD,
prefix,
OFlag::O_DIRECTORY | OFlag::O_NOATIME | OFlag::O_RDONLY | OFlag::O_CLOEXEC,
::nix::sys::stat::Mode::S_IRUSR | ::nix::sys::stat::Mode::S_IXUSR,
)
.or_else(|_| {
::nix::dir::Dir::openat(
::libc::AT_FDCWD,
prefix,
OFlag::O_DIRECTORY | OFlag::O_RDONLY | OFlag::O_CLOEXEC,
::nix::sys::stat::Mode::S_IRUSR | ::nix::sys::stat::Mode::S_IXUSR,
)
}) {
Ok(dir) => dir,
Err(err) => {
debug!(prefix);
debug!(err);
return SmallVec::new();
}
};
let mut buf: Vec<u8> = Vec::with_capacity(BUF_SIZE);
let mut entries = SmallVec::new();
loop {
let n: i64 = unsafe {
::libc::syscall(
::libc::SYS_getdents64,
dir.as_raw_fd(),
buf.as_ptr(),
BUF_SIZE - 256,
)
};
let Ok(n) = usize::try_from(n) else {
return SmallVec::new();
};
if n == 0 {
break;
}
unsafe {
buf.set_len(n);
}
let mut pos = 0;
while pos < n {
let dir = unsafe { std::mem::transmute::<&[u8], &[dirent64]>(&buf[pos..]) };
let entry = unsafe { std::ffi::CStr::from_ptr(dir[0].d_name.as_ptr()) };
if entry.to_bytes() != b"."
&& entry.to_bytes() != b".."
&& entry.to_bytes().starts_with(_match.as_bytes())
{
if dir[0].d_type == ::libc::DT_DIR && !entry.to_bytes().ends_with(b"/") {
let mut s = unsafe {
String::from_utf8_unchecked(
entry.to_bytes()[_match.as_bytes().len()..].to_vec(),
)
};
s.push('/');
entries.push(s);
} else {
entries.push(unsafe {
String::from_utf8_unchecked(
entry.to_bytes()[_match.as_bytes().len()..].to_vec(),
)
});
}
}
pos += dir[0].d_reclen as usize;
}
// https://github.com/romkatv/gitstatus/blob/caf44f7aaf33d0f46e6749e50595323c277e0908/src/dir.cc
// "It's tempting to bail here if n + sizeof(linux_dirent64) +
// 512 <= n. After all, there was enough space
// for another entry but SYS_getdents64 didn't write it, so this
// must be the end of the directory listing,
// right? Unfortunately, no. SYS_getdents64 is finicky.
// It sometimes writes a partial list of entries even if the
// full list would fit."
}
entries
}
#[cfg(not(target_os = "linux"))]
fn complete(&self, force: bool) -> SmallVec<[String; 128]> {
let mut entries = SmallVec::new();
let (prefix, _match) = {
if self.exists() && (!force || self.as_os_str().as_bytes().ends_with(b"/")) {
// println!("{} {:?}", self.display(), self.components().last());
return entries;
} else {
let last_component = self
.components()
.last()
.map(|c| c.as_os_str())
.unwrap_or_else(|| OsStr::from_bytes(b""));
let prefix = if let Some(p) = self.parent() {
p
} else {
return entries;
};
(prefix, last_component)
}
};
if force && self.is_dir() && !self.as_os_str().as_bytes().ends_with(b"/") {
entries.push("/".to_string());
}
if let Ok(iter) = std::fs::read_dir(prefix) {
for entry in iter.flatten() {
if entry.path().as_os_str().as_bytes() != b"."
&& entry.path().as_os_str().as_bytes() != b".."
&& entry
.path()
.as_os_str()
.as_bytes()
.starts_with(_match.as_bytes())
{
if entry.path().is_dir() && !entry.path().as_os_str().as_bytes().ends_with(b"/")
{
let mut s = unsafe {
String::from_utf8_unchecked(
entry.path().as_os_str().as_bytes()[_match.as_bytes().len()..]
.to_vec(),
)
};
s.push('/');
entries.push(s);
} else {
entries.push(unsafe {
String::from_utf8_unchecked(
entry.path().as_os_str().as_bytes()[_match.as_bytes().len()..]
.to_vec(),
)
});
}
}
}
}
entries
}
}
#[test]
fn test_shellexpandtrait() {
assert!(Path::new("~").expand().complete(false).is_empty());
assert!(!Path::new("~").expand().complete(true).is_empty());
}