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|
use std::{
collections::HashMap,
path::{Component, Path, PathBuf},
};
/// Maps paths to access rules.
#[derive(Default, Debug)]
pub struct Shares {
pub exact_rules: HashMap<String, AccessRuleset>,
pub prefix_rules: HashMap<String, AccessRuleset>,
}
impl Shares {
pub fn rules_iter<'a>(&'a self, path: &'a str) -> RulesIter {
RulesIter {
shares: self,
path,
state: RulesIterState::Exact,
}
}
pub fn find_mode<'a>(&'a self, path: &'a str, username: &str) -> Option<&AccessMode> {
for ruleset in self.rules_iter(path) {
if let Some(rule) = ruleset.0.get(username) {
return Some(&rule.mode);
}
}
None
}
}
/// Maps usernames to access modes and .shares.txt source line.
#[derive(Default, Debug)]
pub struct AccessRuleset(pub HashMap<String, AccessRule>);
#[derive(Debug)]
pub struct AccessRule {
pub mode: AccessMode,
pub line: usize,
pub start: usize,
pub end: usize,
}
#[derive(PartialEq, Debug)]
pub enum AccessMode {
ReadAndWrite,
ReadOnly,
}
#[derive(Debug)]
enum RulesIterState {
Exact,
Prefix(usize),
Done,
}
#[derive(Debug)]
pub struct RulesIter<'a> {
shares: &'a Shares,
path: &'a str,
state: RulesIterState,
}
impl<'a> Iterator for RulesIter<'a> {
type Item = &'a AccessRuleset;
fn next(&mut self) -> Option<Self::Item> {
match self.state {
RulesIterState::Exact => {
self.state = RulesIterState::Prefix(self.path.len());
self.shares
.exact_rules
.get(self.path)
.or_else(|| self.next())
}
RulesIterState::Prefix(idx) => {
let path = &self.path[..idx];
if let Some(new_idx) = path.rfind('/') {
self.state = RulesIterState::Prefix(new_idx);
} else {
self.state = RulesIterState::Done;
}
self.shares.prefix_rules.get(path).or_else(|| self.next())
}
RulesIterState::Done => None,
}
}
}
pub fn parse_shares_txt(text: &str) -> Result<Shares, String> {
let mut exact_rules: HashMap<String, AccessRuleset> = HashMap::new();
let mut prefix_rules: HashMap<String, AccessRuleset> = HashMap::new();
let mut start;
let mut next = 0;
for (idx, line) in text.lines().enumerate() {
start = next;
next = start + line.chars().count() + 1;
if line.starts_with('#') || line.trim_end().is_empty() {
continue;
}
let mut iter = line.split('#').next().unwrap().split_ascii_whitespace();
let permissions = iter.next().unwrap();
let path = iter
.next()
.ok_or_else(|| format!("line #{} expected three values", idx + 1))?;
let username = iter
.next()
.ok_or_else(|| format!("line #{} expected three values", idx + 1))?
.trim_end();
if iter.next().is_some() {
return Err(format!(
"line #{} unexpected fourth argument (paths with spaces are unsupported)",
idx + 1
));
}
if permissions != "r" && permissions != "w" {
return Err(format!("line #{} must start with r or w", idx + 1));
}
if username.is_empty() {
return Err(format!("line #{} empty username", idx + 1));
}
if path.is_empty() {
return Err(format!("line #{} empty path", idx + 1));
}
if let (Some(first_ast), Some(last_ast)) = (path.find('*'), path.rfind('*')) {
if first_ast != last_ast || !path.ends_with("/*") {
return Err(format!(
"line #{} wildcards in paths may only occur at the very end as /*",
idx + 1
));
}
}
let rule = AccessRule {
mode: if permissions == "w" {
AccessMode::ReadAndWrite
} else {
AccessMode::ReadOnly
},
line: idx + 1,
start,
end: next,
};
// normalize path
let mut comps = Vec::new();
for comp in Path::new(&*path).components() {
match comp {
Component::Normal(name) => comps.push(name),
Component::ParentDir => {
return Err(format!("line #{}: path may not contain ../", idx + 1))
}
_ => {}
}
}
let path: PathBuf = comps.iter().collect();
let path = path.to_str().unwrap();
if let Some(stripped) = path.strip_suffix("/*") {
let pr = prefix_rules.entry(stripped.to_owned()).or_default();
if let Some(prevrule) = pr.0.get(username) {
if rule.mode != prevrule.mode {
return Err(format!(
"line #{} conflicts with line #{} ({} {})",
idx + 1,
line,
username,
path
));
}
}
pr.0.insert(username.to_string(), rule);
} else {
let ac = exact_rules.entry(path.to_owned()).or_default();
if let Some(prevrule) = ac.0.get(username) {
if rule.mode != prevrule.mode {
return Err(format!(
"line #{} conflicts with line #{} ({} {})",
idx + 1,
line,
username,
path
));
}
}
ac.0.insert(username.to_string(), rule);
}
}
Ok(Shares {
exact_rules,
prefix_rules,
})
}
|
