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|
use std::path::{Path, PathBuf};
use crate::Stack;
/// Access
impl Stack {
/// Returns the top-level path of the stack.
pub fn root(&self) -> &Path {
&self.root
}
/// Returns the absolute path the currently set path.
pub fn current(&self) -> &Path {
&self.current
}
/// Returns the currently set path relative to the [`root()`][Stack::root()].
pub fn current_relative(&self) -> &Path {
&self.current_relative
}
}
/// A delegate for use in a [`Stack`].
pub trait Delegate {
/// Called whenever we push a directory on top of the stack, after the fact.
///
/// It is also called if the currently acted on path is a directory in itself.
/// Use `stack.current()` to see the directory.
fn push_directory(&mut self, stack: &Stack) -> std::io::Result<()>;
/// Called after any component was pushed, with the path available at `stack.current()`.
///
/// `is_last_component` is true if the path is completely built.
fn push(&mut self, is_last_component: bool, stack: &Stack) -> std::io::Result<()>;
/// Called right after a directory-component was popped off the stack.
///
/// Use it to pop information off internal data structures.
fn pop_directory(&mut self);
}
impl Stack {
/// Create a new instance with `root` being the base for all future paths we handle, assuming it to be valid which includes
/// symbolic links to be included in it as well.
pub fn new(root: PathBuf) -> Self {
Stack {
current: root.clone(),
current_relative: PathBuf::with_capacity(128),
valid_components: 0,
root,
current_is_directory: true,
}
}
/// Set the current stack to point to the `relative` path and call `push_comp()` each time a new path component is popped
/// along with the stacks state for inspection to perform an operation that produces some data.
///
/// The full path to `relative` will be returned along with the data returned by `push_comp`.
/// Note that this only works correctly for the delegate's `push_directory()` and `pop_directory()` methods if
/// `relative` paths are terminal, so point to their designated file or directory.
pub fn make_relative_path_current(&mut self, relative: &Path, delegate: &mut dyn Delegate) -> std::io::Result<()> {
debug_assert!(
relative.is_relative(),
"only index paths are handled correctly here, must be relative"
);
debug_assert!(!relative.to_string_lossy().is_empty(), "empty paths are not allowed");
if self.valid_components == 0 {
delegate.push_directory(self)?;
}
let mut components = relative.components().peekable();
let mut existing_components = self.current_relative.components();
let mut matching_components = 0;
while let (Some(existing_comp), Some(new_comp)) = (existing_components.next(), components.peek()) {
if existing_comp == *new_comp {
components.next();
matching_components += 1;
} else {
break;
}
}
for _ in 0..self.valid_components - matching_components {
self.current.pop();
self.current_relative.pop();
if self.current_is_directory {
delegate.pop_directory();
}
self.current_is_directory = true;
}
self.valid_components = matching_components;
if !self.current_is_directory && components.peek().is_some() {
delegate.push_directory(self)?;
}
while let Some(comp) = components.next() {
let is_last_component = components.peek().is_none();
self.current_is_directory = !is_last_component;
self.current.push(comp);
self.current_relative.push(comp);
self.valid_components += 1;
let res = delegate.push(is_last_component, self);
if self.current_is_directory {
delegate.push_directory(self)?;
}
if let Err(err) = res {
self.current.pop();
self.current_relative.pop();
self.valid_components -= 1;
return Err(err);
}
}
Ok(())
}
}
|
