gix_fs/
stack.rs

1use std::path::{Component, Path, PathBuf};
2
3use crate::Stack;
4
5/// Access
6impl Stack {
7    /// Returns the top-level path of the stack.
8    pub fn root(&self) -> &Path {
9        &self.root
10    }
11
12    /// Returns the absolute path the currently set path.
13    pub fn current(&self) -> &Path {
14        &self.current
15    }
16
17    /// Returns the currently set path relative to the [`root()`][Stack::root()].
18    pub fn current_relative(&self) -> &Path {
19        &self.current_relative
20    }
21}
22
23/// A delegate for use in a [`Stack`].
24pub trait Delegate {
25    /// Called whenever we push a directory on top of the stack, and after the respective call to [`push()`](Self::push).
26    ///
27    /// It is only called if the currently acted on path is a directory in itself, which is determined by knowing
28    /// that it's not the last component of the path.
29    /// Use [`Stack::current()`] to see the directory.
30    fn push_directory(&mut self, stack: &Stack) -> std::io::Result<()>;
31
32    /// Called after any component was pushed, with the path available at [`Stack::current()`].
33    ///
34    /// `is_last_component` is `true` if the path is completely built, which typically means it's not a directory.
35    fn push(&mut self, is_last_component: bool, stack: &Stack) -> std::io::Result<()>;
36
37    /// Called right after a directory-component was popped off the stack.
38    ///
39    /// Use it to pop information off internal data structures. Note that no equivalent call exists for popping
40    /// the file-component.
41    fn pop_directory(&mut self);
42}
43
44impl Stack {
45    /// Create a new instance with `root` being the base for all future paths we handle, assuming it to be valid which includes
46    /// symbolic links to be included in it as well.
47    pub fn new(root: PathBuf) -> Self {
48        Stack {
49            current: root.clone(),
50            current_relative: PathBuf::with_capacity(128),
51            valid_components: 0,
52            root,
53            current_is_directory: true,
54        }
55    }
56
57    /// Set the current stack to point to the `relative` path and call `push_comp()` each time a new path component is popped
58    /// along with the stacks state for inspection to perform an operation that produces some data.
59    ///
60    /// The full path to `relative` will be returned along with the data returned by `push_comp`.
61    /// Note that this only works correctly for the delegate's `push_directory()` and `pop_directory()` methods if
62    /// `relative` paths are terminal, so point to their designated file or directory.
63    /// The path is also expected to be normalized, and should not contain extra separators, and must not contain `..`
64    /// or have leading or trailing slashes (or additionally backslashes on Windows).
65    pub fn make_relative_path_current(&mut self, relative: &Path, delegate: &mut dyn Delegate) -> std::io::Result<()> {
66        if self.valid_components != 0 && relative.as_os_str().is_empty() {
67            return Err(std::io::Error::new(
68                std::io::ErrorKind::Other,
69                "empty inputs are not allowed",
70            ));
71        }
72        if self.valid_components == 0 {
73            delegate.push_directory(self)?;
74        }
75
76        let mut components = relative.components().peekable();
77        let mut existing_components = self.current_relative.components();
78        let mut matching_components = 0;
79        while let (Some(existing_comp), Some(new_comp)) = (existing_components.next(), components.peek()) {
80            if existing_comp == *new_comp {
81                components.next();
82                matching_components += 1;
83            } else {
84                break;
85            }
86        }
87
88        for _ in 0..self.valid_components - matching_components {
89            self.current.pop();
90            self.current_relative.pop();
91            if self.current_is_directory {
92                delegate.pop_directory();
93            }
94            self.current_is_directory = true;
95        }
96        self.valid_components = matching_components;
97
98        if !self.current_is_directory && components.peek().is_some() {
99            delegate.push_directory(self)?;
100        }
101
102        while let Some(comp) = components.next() {
103            if !matches!(comp, Component::Normal(_)) {
104                return Err(std::io::Error::new(
105                    std::io::ErrorKind::Other,
106                    format!(
107                        "Input path \"{}\" contains relative or absolute components",
108                        relative.display()
109                    ),
110                ));
111            }
112            let is_last_component = components.peek().is_none();
113            self.current_is_directory = !is_last_component;
114            self.current.push(comp);
115            self.current_relative.push(comp);
116            self.valid_components += 1;
117            let res = delegate.push(is_last_component, self);
118            if self.current_is_directory {
119                delegate.push_directory(self)?;
120            }
121
122            if let Err(err) = res {
123                self.current.pop();
124                self.current_relative.pop();
125                self.valid_components -= 1;
126                return Err(err);
127            }
128        }
129        Ok(())
130    }
131}
gix_fs/stack.rs

gix_fs/
stack.rs
