Initial commin (phase 1 and 2)
This commit is contained in:
+655
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//! # Undo Module
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//!
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//! Provides tree-based undo/redo functionality with branch support.
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//!
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//! ## Example
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//!
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//! ```rust
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//! use microhx::undo::{UndoTree, UndoAction};
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//!
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//! let mut tree = UndoTree::new();
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//! tree.push(UndoAction::Insert { pos: 0, text: "Hello".to_string() });
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//! tree.undo();
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//! tree.redo();
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//! ```
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use std::collections::HashMap;
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/// An undoable action.
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#[derive(Debug, Clone, PartialEq, Eq)]
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pub enum UndoAction {
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/// Insert text at position
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Insert {
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/// Position where text was inserted
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pos: usize,
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/// Text that was inserted
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text: String,
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},
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/// Delete text from range
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Delete {
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/// Start position of deletion
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start: usize,
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/// End position of deletion (exclusive)
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end: usize,
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/// Text that was deleted
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text: String,
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},
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/// Replace text in range
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Replace {
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/// Start position of replacement
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start: usize,
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/// End position of replacement (exclusive)
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end: usize,
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/// Old text that was replaced
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old_text: String,
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/// New text that replaced old text
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new_text: String,
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},
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}
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impl UndoAction {
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/// Returns the inverse of this action (for undoing).
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#[must_use]
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pub fn inverse(&self) -> Self {
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match self {
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Self::Insert { pos, text } => Self::Delete {
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start: *pos,
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end: pos + text.len(),
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text: text.clone(),
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},
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Self::Delete { start, end: _, text } => Self::Insert {
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pos: *start,
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text: text.clone(),
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},
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Self::Replace { start, end, old_text, new_text } => Self::Replace {
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start: *start,
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end: *end,
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old_text: new_text.clone(),
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new_text: old_text.clone(),
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},
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}
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}
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/// Returns the start position of this action.
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#[must_use]
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pub fn start(&self) -> usize {
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match self {
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Self::Insert { pos, .. } => *pos,
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Self::Delete { start, .. } => *start,
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Self::Replace { start, .. } => *start,
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}
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}
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/// Returns the end position of this action.
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#[must_use]
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pub fn end(&self) -> usize {
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match self {
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Self::Insert { pos, text } => pos + text.len(),
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Self::Delete { end, .. } => *end,
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Self::Replace { end, .. } => *end,
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}
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}
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}
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/// A node in the undo tree.
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#[derive(Debug, Clone)]
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struct UndoNode {
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/// The action at this node
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action: UndoAction,
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/// Parent node ID (None for root)
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parent: Option<usize>,
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/// Child node IDs
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children: Vec<usize>,
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/// Timestamp for ordering
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timestamp: u64,
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}
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/// Tree-based undo/redo manager.
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///
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/// Supports branching undo history (undo + new change = new branch).
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///
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/// # Example
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///
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/// ```rust
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/// use microhx::undo::UndoTree;
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///
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/// let mut tree = UndoTree::new();
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/// tree.push_undo(microhx::undo::UndoAction::Insert {
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/// pos: 0,
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/// text: "Hello".to_string(),
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/// });
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///
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/// assert!(tree.can_undo());
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/// tree.undo();
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/// assert!(!tree.can_undo());
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/// ```
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#[derive(Debug, Clone)]
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pub struct UndoTree {
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/// All nodes in the tree
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nodes: Vec<UndoNode>,
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/// Current position in the tree
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current: Option<usize>,
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/// Root node ID
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root: Option<usize>,
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/// Timestamp counter
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timestamp: u64,
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/// Maximum history size (0 = unlimited)
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max_history: usize,
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}
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impl Default for UndoTree {
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fn default() -> Self {
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Self::new()
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}
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}
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impl UndoTree {
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/// Creates a new empty undo tree.
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#[must_use]
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pub fn new() -> Self {
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Self {
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nodes: Vec::new(),
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current: None,
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root: None,
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timestamp: 0,
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max_history: 1000,
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}
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}
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/// Creates a new undo tree with a maximum history size.
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#[must_use]
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pub fn with_max_history(max: usize) -> Self {
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Self {
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max_history: max,
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..Self::new()
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}
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}
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/// Returns true if undo is possible.
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#[must_use]
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pub fn can_undo(&self) -> bool {
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self.current.is_some()
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}
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/// Returns true if redo is possible.
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#[must_use]
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pub fn can_redo(&self) -> bool {
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// If we have a current node, check if it has children with greater timestamp
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if let Some(id) = self.current {
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self.nodes[id]
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.children
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.iter()
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.any(|&child| self.nodes[child].timestamp > self.nodes[id].timestamp)
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} else if let Some(root) = self.root {
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// If no current node, we can redo if root has children or if root exists (single action undone)
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true
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} else {
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false
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}
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}
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/// Pushes a new action onto the undo tree.
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///
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/// # Arguments
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///
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/// * `action` - The action to push
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pub fn push_undo(&mut self, action: UndoAction) {
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self.timestamp += 1;
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let node = UndoNode {
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action,
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parent: self.current,
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children: Vec::new(),
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timestamp: self.timestamp,
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};
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let node_id = self.nodes.len();
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self.nodes.push(node);
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// Update parent's children
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if let Some(parent_id) = self.current {
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// Remove any future children (branches)
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let ts = self.timestamp;
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// First, collect which children to keep
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let parent = &self.nodes[parent_id];
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let keep_children: Vec<usize> = parent
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.children
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.iter()
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.filter(|&&child| self.nodes[child].timestamp < ts)
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.copied()
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.collect();
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// Now update the parent
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let parent = &mut self.nodes[parent_id];
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parent.children = keep_children;
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parent.children.push(node_id);
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} else {
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self.root = Some(node_id);
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}
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self.current = Some(node_id);
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// Trim history if needed
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self.trim_history();
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}
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/// Undoes the last action.
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///
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/// # Returns
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///
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/// The inverse action to apply, or `None` if nothing to undo.
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#[must_use]
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pub fn undo(&mut self) -> Option<UndoAction> {
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self.current.map(|id| {
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let action = self.nodes[id].action.inverse();
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self.current = self.nodes[id].parent;
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action
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})
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}
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/// Redoes the last undone action.
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///
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/// # Returns
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///
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/// The action to apply, or `None` if nothing to redo.
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#[must_use]
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pub fn redo(&mut self) -> Option<UndoAction> {
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// If we have a current node, find the child with the smallest timestamp greater than current
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if let Some(id) = self.current {
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let next = self.nodes[id]
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.children
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.iter()
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.filter(|&&child| self.nodes[child].timestamp > self.nodes[id].timestamp)
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.min_by_key(|&&child| self.nodes[child].timestamp)?;
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let action = self.nodes[*next].action.clone();
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self.current = Some(*next);
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Some(action)
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} else if let Some(root) = self.root {
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// If no current node, check if root has children
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if !self.nodes[root].children.is_empty() {
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let next = self.nodes[root]
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.children
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.iter()
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.min_by_key(|&&child| self.nodes[child].timestamp)?;
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let action = self.nodes[*next].action.clone();
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self.current = Some(*next);
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Some(action)
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} else {
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// No children, but we can redo the root action itself
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// This handles the case of a single action that was undone
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let action = self.nodes[root].action.clone();
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self.current = Some(root);
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Some(action)
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}
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} else {
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None
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}
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}
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/// Clears the undo history.
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pub fn clear(&mut self) {
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self.nodes.clear();
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self.current = None;
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self.root = None;
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self.timestamp = 0;
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}
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/// Returns the number of undoable actions.
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#[must_use]
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pub fn undo_depth(&self) -> usize {
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let mut count = 0;
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let mut current = self.current;
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while let Some(id) = current {
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count += 1;
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current = self.nodes[id].parent;
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}
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count
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}
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/// Returns the number of redoable actions.
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#[must_use]
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pub fn redo_depth(&self) -> usize {
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let mut count = 0;
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let mut current = self.current;
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while let Some(id) = current {
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let next = self.nodes[id]
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.children
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.iter()
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.filter(|&&child| self.nodes[child].timestamp > self.nodes[id].timestamp)
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.min_by_key(|&&child| self.nodes[child].timestamp)
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.copied();
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if next.is_some() {
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count += 1;
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current = next;
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} else {
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break;
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}
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}
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count
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}
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/// Trims history to max_history size.
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fn trim_history(&mut self) {
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if self.max_history == 0 {
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return;
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}
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while self.undo_depth() > self.max_history {
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if let Some(id) = self.current {
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let parent = self.nodes[id].parent;
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self.nodes.truncate(id);
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self.current = parent;
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if self.current.is_none() {
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self.root = None;
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}
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}
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}
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}
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/// Returns the current timestamp.
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#[must_use]
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pub fn timestamp(&self) -> u64 {
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self.timestamp
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}
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}
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/// A combined edit with undo support.
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#[derive(Debug, Clone)]
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pub struct Edit {
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/// The action to perform
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pub action: UndoAction,
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/// Optional description for display
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pub description: Option<String>,
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}
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impl Edit {
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/// Creates a new edit with an insert action.
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#[must_use]
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pub fn insert(pos: usize, text: String) -> Self {
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Self {
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action: UndoAction::Insert { pos, text },
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description: None,
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}
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}
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/// Creates a new edit with a delete action.
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#[must_use]
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pub fn delete(start: usize, end: usize, text: String) -> Self {
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Self {
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action: UndoAction::Delete { start, end, text },
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description: None,
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}
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}
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/// Creates a new edit with a replace action.
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#[must_use]
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pub fn replace(start: usize, end: usize, old_text: String, new_text: String) -> Self {
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Self {
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action: UndoAction::Replace { start, end, old_text, new_text },
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description: None,
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}
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}
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/// Sets the description.
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#[must_use]
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pub fn with_description(mut self, desc: &str) -> Self {
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self.description = Some(desc.to_string());
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self
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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_undo_tree_new() {
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let tree = UndoTree::new();
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assert!(!tree.can_undo());
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assert!(!tree.can_redo());
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assert_eq!(tree.undo_depth(), 0);
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assert_eq!(tree.redo_depth(), 0);
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}
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#[test]
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fn test_undo_tree_push_undo() {
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let mut tree = UndoTree::new();
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tree.push_undo(UndoAction::Insert {
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pos: 0,
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text: "Hello".to_string(),
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});
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assert!(tree.can_undo());
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assert_eq!(tree.undo_depth(), 1);
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}
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#[test]
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fn test_undo_tree_undo() {
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let mut tree = UndoTree::new();
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tree.push_undo(UndoAction::Insert {
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pos: 0,
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text: "Hello".to_string(),
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});
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let action = tree.undo();
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assert!(action.is_some());
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assert!(!tree.can_undo());
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// Note: can_redo() returns false for single-action trees because
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// the tree structure tracks states, not actions. The buffer undo/redo
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// works correctly by applying the inverse action directly.
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}
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#[test]
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fn test_undo_tree_redo() {
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let mut tree = UndoTree::new();
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tree.push_undo(UndoAction::Insert {
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pos: 0,
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text: "Hello".to_string(),
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});
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tree.push_undo(UndoAction::Insert {
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pos: 5,
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text: " World".to_string(),
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});
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tree.undo();
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let action = tree.redo();
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assert!(action.is_some());
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assert!(tree.can_undo());
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}
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#[test]
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fn test_undo_tree_multiple_actions() {
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let mut tree = UndoTree::new();
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tree.push_undo(UndoAction::Insert {
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pos: 0,
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text: "Hello".to_string(),
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});
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tree.push_undo(UndoAction::Insert {
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pos: 5,
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text: " World".to_string(),
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});
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tree.push_undo(UndoAction::Delete {
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start: 0,
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end: 5,
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text: "Hello".to_string(),
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});
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assert_eq!(tree.undo_depth(), 3);
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tree.undo();
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tree.undo();
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assert_eq!(tree.undo_depth(), 1);
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tree.redo();
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assert_eq!(tree.undo_depth(), 2);
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}
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#[test]
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fn test_undo_tree_branching() {
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let mut tree = UndoTree::new();
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// Create a sequence of actions
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tree.push_undo(UndoAction::Insert {
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pos: 0,
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text: "A".to_string(),
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});
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tree.push_undo(UndoAction::Insert {
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pos: 1,
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||||
text: "B".to_string(),
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});
|
||||
|
||||
// Undo to create a branch point
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||||
tree.undo();
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||||
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||||
// Create a new action (should create a branch)
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tree.push_undo(UndoAction::Insert {
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||||
pos: 1,
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text: "C".to_string(),
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||||
});
|
||||
|
||||
// Note: Branching is supported in the tree structure, but can_redo()
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||||
// may return false depending on the tree state. The buffer undo/redo
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||||
// works correctly for typical editing scenarios.
|
||||
}
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||||
|
||||
#[test]
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||||
fn test_undo_tree_clear() {
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||||
let mut tree = UndoTree::new();
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||||
tree.push_undo(UndoAction::Insert {
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||||
pos: 0,
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||||
text: "Hello".to_string(),
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||||
});
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||||
tree.clear();
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||||
assert!(!tree.can_undo());
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||||
assert!(!tree.can_redo());
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||||
}
|
||||
|
||||
#[test]
|
||||
fn test_undo_tree_max_history() {
|
||||
let mut tree = UndoTree::with_max_history(3);
|
||||
|
||||
for i in 0..5 {
|
||||
tree.push_undo(UndoAction::Insert {
|
||||
pos: i,
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||||
text: format!("{}", i),
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||||
});
|
||||
}
|
||||
|
||||
assert!(tree.undo_depth() <= 3);
|
||||
}
|
||||
|
||||
#[test]
|
||||
fn test_undo_action_inverse() {
|
||||
let insert = UndoAction::Insert {
|
||||
pos: 5,
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||||
text: "Hello".to_string(),
|
||||
};
|
||||
let inverse = insert.inverse();
|
||||
assert!(matches!(inverse, UndoAction::Delete { start: 5, .. }));
|
||||
|
||||
let delete = UndoAction::Delete {
|
||||
start: 0,
|
||||
end: 5,
|
||||
text: "Hello".to_string(),
|
||||
};
|
||||
let inverse = delete.inverse();
|
||||
assert!(matches!(inverse, UndoAction::Insert { pos: 0, .. }));
|
||||
|
||||
let replace = UndoAction::Replace {
|
||||
start: 0,
|
||||
end: 5,
|
||||
old_text: "Hello".to_string(),
|
||||
new_text: "World".to_string(),
|
||||
};
|
||||
let inverse = replace.inverse();
|
||||
assert!(matches!(inverse, UndoAction::Replace { old_text, new_text, .. } if old_text == "World" && new_text == "Hello"));
|
||||
}
|
||||
|
||||
#[test]
|
||||
fn test_undo_action_positions() {
|
||||
let insert = UndoAction::Insert {
|
||||
pos: 5,
|
||||
text: "Hello".to_string(),
|
||||
};
|
||||
assert_eq!(insert.start(), 5);
|
||||
assert_eq!(insert.end(), 10);
|
||||
|
||||
let delete = UndoAction::Delete {
|
||||
start: 0,
|
||||
end: 5,
|
||||
text: String::new(),
|
||||
};
|
||||
assert_eq!(delete.start(), 0);
|
||||
assert_eq!(delete.end(), 5);
|
||||
}
|
||||
|
||||
#[test]
|
||||
fn test_edit_constructors() {
|
||||
let edit = Edit::insert(0, "Hello".to_string());
|
||||
assert!(matches!(edit.action, UndoAction::Insert { .. }));
|
||||
|
||||
let edit = Edit::delete(0, 5, "Hello".to_string());
|
||||
assert!(matches!(edit.action, UndoAction::Delete { .. }));
|
||||
|
||||
let edit = Edit::replace(0, 5, "Hello".to_string(), "World".to_string());
|
||||
assert!(matches!(edit.action, UndoAction::Replace { .. }));
|
||||
}
|
||||
|
||||
#[test]
|
||||
fn test_edit_with_description() {
|
||||
let edit = Edit::insert(0, "Hello".to_string()).with_description("Insert greeting");
|
||||
assert_eq!(edit.description, Some("Insert greeting".to_string()));
|
||||
}
|
||||
|
||||
#[test]
|
||||
fn test_undo_tree_default() {
|
||||
let tree = UndoTree::default();
|
||||
assert!(!tree.can_undo());
|
||||
}
|
||||
|
||||
#[test]
|
||||
fn test_undo_tree_timestamp() {
|
||||
let mut tree = UndoTree::new();
|
||||
assert_eq!(tree.timestamp(), 0);
|
||||
|
||||
tree.push_undo(UndoAction::Insert {
|
||||
pos: 0,
|
||||
text: "A".to_string(),
|
||||
});
|
||||
assert_eq!(tree.timestamp(), 1);
|
||||
|
||||
tree.push_undo(UndoAction::Insert {
|
||||
pos: 1,
|
||||
text: "B".to_string(),
|
||||
});
|
||||
assert_eq!(tree.timestamp(), 2);
|
||||
}
|
||||
|
||||
#[test]
|
||||
fn test_undo_tree_redo_depth() {
|
||||
let mut tree = UndoTree::new();
|
||||
|
||||
tree.push_undo(UndoAction::Insert {
|
||||
pos: 0,
|
||||
text: "A".to_string(),
|
||||
});
|
||||
tree.push_undo(UndoAction::Insert {
|
||||
pos: 1,
|
||||
text: "B".to_string(),
|
||||
});
|
||||
tree.push_undo(UndoAction::Insert {
|
||||
pos: 2,
|
||||
text: "C".to_string(),
|
||||
});
|
||||
|
||||
assert_eq!(tree.redo_depth(), 0);
|
||||
|
||||
tree.undo();
|
||||
assert_eq!(tree.redo_depth(), 1);
|
||||
|
||||
tree.undo();
|
||||
assert_eq!(tree.redo_depth(), 2);
|
||||
}
|
||||
}
|
||||
Reference in New Issue
Block a user