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use std::{env, path::{Component, Path, PathBuf}};
#[derive(Debug)]
pub enum NormalizeError {
EmptyInput,
CwdNotAbsolute,
InputOutsideFileSystemRoot,
}
pub fn normalize_path(root: &Path, origin: &Path, input: &Path) -> Result<PathBuf, NormalizeError> {
let cwd = env::current_dir().map_err(|_| NormalizeError::CwdNotAbsolute)?;
normalize_path_with_preset_cwd(root, origin, input, &cwd)
}
fn normalize_path_with_preset_cwd(
root: &Path,
origin: &Path,
input: &Path,
cwd: &Path,
) -> Result<PathBuf, NormalizeError> {
if input.as_os_str().is_empty() {
return Err(NormalizeError::EmptyInput);
}
if !cwd.is_absolute() {
return Err(NormalizeError::CwdNotAbsolute);
}
let input = if input.is_absolute() {
input.to_path_buf()
} else if origin.is_absolute() {
origin.join(input)
} else {
cwd.join(origin).join(input)
};
let root = if root.is_absolute() {
root.to_path_buf()
} else {
cwd.join(root)
};
let normalized_input = normalize_lexically(&input)?;
Ok(normalize_to_root(normalized_input, &root))
}
fn normalize_lexically(path: &Path) -> Result<PathBuf, NormalizeError> {
let mut lexical = PathBuf::new();
let mut iter = path.components().peekable();
// Find the root, if any, and add it to the lexical path.
// Here we treat the Windows path "C:\" as a single "root" even though
// `components` splits it into two: (Prefix, RootDir).
let root = match iter.peek() {
Some(Component::ParentDir) => return Err(NormalizeError::InputOutsideFileSystemRoot),
Some(p @ Component::RootDir) | Some(p @ Component::CurDir) => {
lexical.push(p);
iter.next();
lexical.as_os_str().len()
}
Some(Component::Prefix(prefix)) => {
lexical.push(prefix.as_os_str());
iter.next();
if let Some(p @ Component::RootDir) = iter.peek() {
lexical.push(p);
iter.next();
}
lexical.as_os_str().len()
}
None => return Ok(PathBuf::new()),
Some(Component::Normal(_)) => 0,
};
for component in iter {
match component {
Component::RootDir => unreachable!(),
Component::Prefix(_) => return Err(NormalizeError::InputOutsideFileSystemRoot),
Component::CurDir => continue,
Component::ParentDir => {
// It's an error if ParentDir causes us to go above the "root".
if lexical.as_os_str().len() == root {
return Err(NormalizeError::InputOutsideFileSystemRoot);
} else {
lexical.pop();
}
}
Component::Normal(path) => lexical.push(path),
}
}
Ok(lexical)
}
fn normalize_to_root(target: PathBuf, mut root: &Path) -> PathBuf {
let mut prefix = PathBuf::new();
loop {
if let Ok(suffix) = target.strip_prefix(root) {
return prefix.join(suffix);
}
if let Some(new_root) = root.parent() {
prefix.push("..");
root = new_root;
} else {
return target;
}
}
}
#[cfg(test)]
mod tests {
use std::path::Path;
use super::{NormalizeError, normalize_path_with_preset_cwd};
#[test]
fn empty_path_returns_error() {
let fake_cwd = Path::new("/sandbox");
let root = Path::new("");
let origin_dir = Path::new("");
let input = Path::new("");
let result = normalize_path_with_preset_cwd(root, origin_dir, input, fake_cwd);
assert!(matches!(result, Err(NormalizeError::EmptyInput)));
}
#[test]
fn plain_filename_with_root_at_cwd_returns_filename() {
let fake_cwd = Path::new("/sandbox");
let root = Path::new("");
let origin_dir = Path::new("");
let input = Path::new("main.rs");
let result = normalize_path_with_preset_cwd(root, origin_dir, input, fake_cwd);
assert!(result.is_ok());
assert_eq!(result.unwrap(), Path::new("main.rs"));
}
#[test]
fn relative_path_from_origin_is_resolved() {
let fake_cwd = Path::new("/sandbox");
let root = Path::new("");
let origin_dir = Path::new("src");
let input = Path::new("../main.rs");
let result = normalize_path_with_preset_cwd(root, origin_dir, input, fake_cwd);
assert!(result.is_ok());
assert_eq!(result.unwrap(), Path::new("main.rs"));
}
#[test]
fn path_is_made_relative_to_root() {
let fake_cwd = Path::new("/sandbox");
let root = Path::new("/project");
let origin_dir = Path::new("/project/src");
let input = Path::new("main.rs");
let result = normalize_path_with_preset_cwd(root, origin_dir, input, fake_cwd);
assert_eq!(result.unwrap(), Path::new("src/main.rs"));
}
#[test]
fn path_is_made_relative_to_root_from_outside() {
let fake_cwd = Path::new("/sandbox");
let root = Path::new("/project");
let origin_dir = Path::new("/outside");
let input = Path::new("main.rs");
let result = normalize_path_with_preset_cwd(root, origin_dir, input, fake_cwd);
assert_eq!(result.unwrap(), Path::new("../outside/main.rs"));
}
#[test]
fn path_is_made_relative_to_root_even_if_root_dir_is_relative() {
let fake_cwd = Path::new("/sandbox");
let root = Path::new("project");
let origin_dir = Path::new("/sandbox/outside");
let input = Path::new("main.rs");
let result = normalize_path_with_preset_cwd(root, origin_dir, input, fake_cwd);
assert_eq!(result.unwrap(), Path::new("../outside/main.rs"));
}
#[test]
fn absolute_inputs_work() {
let fake_cwd = Path::new("/sandbox");
let root = Path::new("project");
let origin_dir = Path::new("/sandbox/outside");
let input = Path::new("/sandbox/main.rs");
let result = normalize_path_with_preset_cwd(root, origin_dir, input, fake_cwd);
assert_eq!(result.unwrap(), Path::new("../main.rs"));
}
#[test]
fn path_is_made_relative_to_root_even_if_origin_dir_is_relative() {
let fake_cwd = Path::new("/sandbox");
let root = Path::new("/sandbox/project");
let origin_dir = Path::new("outside");
let input = Path::new("main.rs");
let result = normalize_path_with_preset_cwd(root, origin_dir, input, fake_cwd);
assert_eq!(result.unwrap(), Path::new("../outside/main.rs"));
}
#[test]
fn input_cannot_go_above_root() {
let fake_cwd = Path::new("/sandbox");
let root = Path::new("project");
let origin_dir = Path::new("outside");
let input = Path::new("../../../main.rs");
let result = normalize_path_with_preset_cwd(root, origin_dir, input, fake_cwd);
assert!(matches!(result, Err(NormalizeError::InputOutsideFileSystemRoot)));
}
}
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