likewise/src/algorithms/capture.rs
2021-01-18 21:37:04 +01:00

112 lines
2.5 KiB
Rust

use crate::algorithms::hook::DiffHook;
use std::convert::Infallible;
/// Utility enum to capture a diff operation.
///
/// This is used by [`Capture`](crate::algorithms::Capture).
#[derive(Debug, PartialEq, Eq, Hash, Clone, Copy)]
pub enum DiffOp {
/// A segment is equal (see [`DiffHook::equal`])
Equal {
old_index: usize,
new_index: usize,
len: usize,
},
/// A segment was deleted (see [`DiffHook::delete`])
Delete {
old_index: usize,
old_len: usize,
new_index: usize,
},
/// A segment was inserted (see [`DiffHook::insert`])
Insert {
old_index: usize,
new_index: usize,
new_len: usize,
},
/// A segment was replaced (see [`DiffHook::replace`])
Replace {
old_index: usize,
old_len: usize,
new_index: usize,
new_len: usize,
},
}
/// A [`DiffHook`] that captures all diff operations.
#[derive(Default, Clone)]
pub struct Capture(Vec<DiffOp>);
impl Capture {
/// Creates a new capture hook.
pub fn new() -> Capture {
Capture::default()
}
/// Converts the capture hook into a vector.
pub fn into_vec(self) -> Vec<DiffOp> {
self.0
}
/// Accesses the captured operations.
pub fn ops(&self) -> &[DiffOp] {
&self.0
}
}
impl DiffHook for Capture {
type Error = Infallible;
fn equal(&mut self, old_index: usize, new_index: usize, len: usize) -> Result<(), Self::Error> {
self.0.push(DiffOp::Equal {
old_index,
new_index,
len,
});
Ok(())
}
fn delete(
&mut self,
old_index: usize,
old_len: usize,
new_index: usize,
) -> Result<(), Self::Error> {
self.0.push(DiffOp::Delete {
old_index,
old_len,
new_index,
});
Ok(())
}
fn insert(
&mut self,
old_index: usize,
new_index: usize,
new_len: usize,
) -> Result<(), Self::Error> {
self.0.push(DiffOp::Insert {
old_index,
new_index,
new_len,
});
Ok(())
}
fn replace(
&mut self,
old_index: usize,
old_len: usize,
new_index: usize,
new_len: usize,
) -> Result<(), Self::Error> {
self.0.push(DiffOp::Replace {
old_index,
old_len,
new_index,
new_len,
});
Ok(())
}
}