143 lines
4 KiB
Rust
143 lines
4 KiB
Rust
use std::cmp::Ordering;
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use ropey::Rope;
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use serde::{Deserialize, Serialize};
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use similar::{Change, ChangeTag};
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use crate::errors::SyncLibError;
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#[derive(Debug, Clone, PartialEq, Eq, Hash, Serialize, Deserialize)]
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pub enum Operation {
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Insert {
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index: u64,
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text: String,
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},
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Delete {
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index: u64,
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deleted_character_count: u64,
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},
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}
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impl Operation {
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pub fn new(tag: ChangeTag, index: u64, text: &str) -> Self {
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match tag {
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ChangeTag::Insert => Operation::Insert {
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index,
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text: text.to_string(),
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},
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ChangeTag::Delete => Operation::Delete {
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index,
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deleted_character_count: text.chars().count() as u64,
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},
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_ => panic!("Only insertion and deletions are supported"),
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}
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}
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pub fn apply<'a>(&self, rope_text: &'a mut Rope) -> Result<&'a mut Rope, SyncLibError> {
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let index: usize = self.index() as usize;
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match self {
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Operation::Insert { text, .. } => rope_text.try_insert(index, &text).map_err(|err| {
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SyncLibError::OperationApplicationError(format!("Failed to insert text: {}", err))
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}),
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Operation::Delete {
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deleted_character_count,
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..
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} => rope_text
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.try_remove(index..index + *deleted_character_count as usize)
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.map_err(|err| {
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SyncLibError::OperationApplicationError(format!(
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"Failed to remove text: {}",
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err
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))
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}),
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}?;
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Ok(rope_text)
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}
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pub fn index(&self) -> u64 {
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match self {
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Operation::Insert { index, .. } => *index,
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Operation::Delete { index, .. } => *index,
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}
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}
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pub fn with_index(&self, index: u64) -> Self {
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match self {
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Operation::Insert { text, .. } => Operation::Insert {
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index,
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text: text.clone(),
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},
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Operation::Delete {
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deleted_character_count,
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..
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} => Operation::Delete {
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index,
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deleted_character_count: *deleted_character_count,
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},
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}
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}
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pub fn with_shifted_index(&self, offset: i64) -> Result<Self, SyncLibError> {
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let new_index: i64 = self.index() as i64 + offset;
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let new_index: u64 = new_index
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.try_into()
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.map_err(|err| SyncLibError::OperationShiftingError(format!("{}", err)))?;
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Ok(self.with_index(new_index))
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}
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}
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impl Ord for Operation {
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fn cmp(&self, other: &Self) -> Ordering {
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let result = self.index().cmp(&other.index());
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if result == Ordering::Equal {
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match (self, other) {
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(Operation::Insert { .. }, Operation::Delete { .. }) => Ordering::Greater,
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(Operation::Delete { .. }, Operation::Insert { .. }) => Ordering::Less,
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_ => Ordering::Equal,
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}
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} else {
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result
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}
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}
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}
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impl PartialOrd for Operation {
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fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
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Some(self.cmp(&other))
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}
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}
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#[cfg(test)]
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mod tests {
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use super::*;
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#[test]
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fn test_apply_delete() -> Result<(), SyncLibError> {
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let mut rope = Rope::from_str("hello world");
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let operation = Operation::Delete {
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index: 5,
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deleted_character_count: 6,
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};
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operation.apply(&mut rope)?;
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assert_eq!(rope.to_string(), "hello");
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Ok(())
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}
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#[test]
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fn test_apply_insert() -> Result<(), SyncLibError> {
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let mut rope = Rope::from_str("hello");
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let operation = Operation::Insert {
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index: 5,
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text: " my friend".to_string(),
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};
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operation.apply(&mut rope)?;
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assert_eq!(rope.to_string(), "hello my friend");
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Ok(())
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}
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}
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