ropey/tree/node.rs
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use std::sync::Arc;
use crate::str_utils::{
byte_to_char_idx, byte_to_line_idx, byte_to_utf16_surrogate_idx, char_to_byte_idx,
};
use crate::tree::node_text::fix_segment_seam;
use crate::tree::{
Count, NodeChildren, NodeText, TextInfo, MAX_BYTES, MAX_CHILDREN, MIN_BYTES, MIN_CHILDREN,
};
#[derive(Debug, Clone)]
#[repr(u8, C)]
pub(crate) enum Node {
Leaf(NodeText),
Internal(NodeChildren),
}
impl Node {
/// Creates an empty node.
#[inline(always)]
pub fn new() -> Self {
Node::Leaf(NodeText::from_str(""))
}
/// Total number of bytes in the Rope.
#[inline(always)]
pub fn byte_count(&self) -> usize {
self.text_info().bytes as usize
}
/// Total number of chars in the Rope.
#[inline(always)]
pub fn char_count(&self) -> usize {
self.text_info().chars as usize
}
/// Total number of line breaks in the Rope.
#[inline(always)]
pub fn line_break_count(&self) -> usize {
self.text_info().line_breaks as usize
}
/// Total number of line breaks in the Rope.
#[inline(always)]
pub fn utf16_surrogate_count(&self) -> usize {
self.text_info().utf16_surrogates as usize
}
/// Fetches a chunk mutably, and allows it to be edited via a closure.
///
/// There are three parameters:
/// - char_idx: the chunk that contains this char is fetched,
/// - node_info: this is the text info of the node it's being called on.
/// This makes it a little awkward to call, but is needed since
/// it's actually the parent node that contains the text info,
/// so the info needs to be passed in.
/// - edit: the closure that receives the chunk and does the edits.
///
/// The closure is effectively the termination case for the recursion,
/// and takes essentially same parameters and returns the same things as
/// the method itself. In particular, the closure receives the char offset
/// of char_idx within the given chunk and the TextInfo of the chunk.
/// The main difference is that it receives a NodeText instead of a node.
///
/// The closure is expected to return the updated text info of the node,
/// and if the node had to be split, then it also returns the right-hand
/// node along with its TextInfo as well.
///
/// The main method call will then return the total updated TextInfo for
/// the whole tree, and a new node only if the whole tree had to be split.
/// It is up to the caller to check for that new node, and handle it by
/// creating a new root with both the original node and the new node as
/// children.
pub fn edit_chunk_at_char<F>(
&mut self,
char_idx: usize,
node_info: TextInfo,
mut edit: F,
) -> (TextInfo, Option<(TextInfo, Arc<Node>)>)
where
F: FnMut(usize, TextInfo, &mut NodeText) -> (TextInfo, Option<(TextInfo, Arc<Node>)>),
{
match *self {
Node::Leaf(ref mut leaf_text) => edit(char_idx, node_info, leaf_text),
Node::Internal(ref mut children) => {
// Compact leaf children if we're very close to maximum leaf
// fragmentation. This basically guards against excessive memory
// ballooning when repeatedly appending to the end of a rope.
// The constant here was arrived at experimentally, and is otherwise
// fairly arbitrary.
const FRAG_MIN_BYTES: usize = (MAX_BYTES * MIN_CHILDREN) + (MAX_BYTES / 32);
if children.is_full()
&& children.nodes()[0].is_leaf()
&& (children.combined_info().bytes as usize) < FRAG_MIN_BYTES
{
children.compact_leaves();
}
// Find the child we care about.
let (child_i, acc_char_idx) = children.search_char_idx_only(char_idx);
let info = children.info()[child_i];
// Recurse into the child.
let (l_info, residual) = Arc::make_mut(&mut children.nodes_mut()[child_i])
.edit_chunk_at_char(char_idx - acc_char_idx, info, edit);
children.info_mut()[child_i] = l_info;
// Handle the residual node if there is one and return.
if let Some((r_info, r_node)) = residual {
if children.len() < MAX_CHILDREN {
children.insert(child_i + 1, (r_info, r_node));
(node_info - info + l_info + r_info, None)
} else {
let r = children.insert_split(child_i + 1, (r_info, r_node));
let r_info = r.combined_info();
(
children.combined_info(),
Some((r_info, Arc::new(Node::Internal(r)))),
)
}
} else {
(node_info - info + l_info, None)
}
}
}
}
/// Removes chars in the range `start_idx..end_idx`.
///
/// Returns (in this order):
/// - The updated TextInfo for the node.
/// - Whether there's a possible CRLF seam that needs fixing.
/// - Whether fix_tree_seam() needs to be run after this.
///
/// WARNING: does not correctly handle all text being removed. That
/// should be special-cased in calling code.
pub fn remove_char_range(
&mut self,
start_idx: usize,
end_idx: usize,
node_info: TextInfo,
) -> (TextInfo, bool, bool) {
if start_idx == end_idx {
return (node_info, false, false);
}
match *self {
// If it's a leaf
Node::Leaf(ref mut leaf_text) => {
let byte_start = char_to_byte_idx(leaf_text, start_idx);
let byte_end =
byte_start + char_to_byte_idx(&leaf_text[byte_start..], end_idx - start_idx);
// Remove text and calculate new info & seam info
if byte_start > 0 || byte_end < leaf_text.len() {
let seam = (byte_start == 0 && leaf_text.as_bytes()[byte_end] == 0x0A)
|| (byte_end == leaf_text.len()
&& leaf_text.as_bytes()[byte_start - 1] == 0x0D);
let seg_len = byte_end - byte_start; // Length of removal segement
if seg_len < (leaf_text.len() - seg_len) {
#[allow(unused_mut)]
let mut info =
node_info - TextInfo::from_str(&leaf_text[byte_start..byte_end]);
// Check for CRLF pairs on the removal seams, and
// adjust line break counts accordingly.
#[cfg(any(feature = "cr_lines", feature = "unicode_lines"))]
{
if byte_end < leaf_text.len()
&& leaf_text.as_bytes()[byte_end - 1] == 0x0D
&& leaf_text.as_bytes()[byte_end] == 0x0A
{
info.line_breaks += 1;
}
if byte_start > 0 && leaf_text.as_bytes()[byte_start - 1] == 0x0D {
if leaf_text.as_bytes()[byte_start] == 0x0A {
info.line_breaks += 1;
}
if byte_end < leaf_text.len()
&& leaf_text.as_bytes()[byte_end] == 0x0A
{
info.line_breaks -= 1;
}
}
}
// Remove the text
leaf_text.remove_range(byte_start, byte_end);
(info, seam, false)
} else {
// Remove the text
leaf_text.remove_range(byte_start, byte_end);
(TextInfo::from_str(leaf_text), seam, false)
}
} else {
// Remove all of the text
leaf_text.remove_range(byte_start, byte_end);
(TextInfo::new(), true, false)
}
}
// If it's internal, it's much more complicated
Node::Internal(ref mut children) => {
// Shared code for handling children.
// Returns (in this order):
// - Whether there's a possible CRLF seam that needs fixing.
// - Whether the tree may need invariant fixing.
// - Updated TextInfo of the node.
let handle_child = |children: &mut NodeChildren,
child_i: usize,
c_char_acc: usize|
-> (bool, bool, TextInfo) {
// Recurse into child
let tmp_info = children.info()[child_i];
let tmp_chars = children.info()[child_i].chars as usize;
let (new_info, seam, needs_fix) =
Arc::make_mut(&mut children.nodes_mut()[child_i]).remove_char_range(
start_idx - c_char_acc.min(start_idx),
(end_idx - c_char_acc).min(tmp_chars),
tmp_info,
);
// Handle result
if new_info.bytes == 0 {
children.remove(child_i);
} else {
children.info_mut()[child_i] = new_info;
}
(seam, needs_fix, new_info)
};
// Shared code for merging children
let merge_child = |children: &mut NodeChildren, child_i: usize| {
if child_i < children.len()
&& children.len() > 1
&& children.nodes()[child_i].is_undersized()
{
if child_i == 0 {
children.merge_distribute(child_i, child_i + 1);
} else {
children.merge_distribute(child_i - 1, child_i);
}
}
};
// Get child info for the two char indices
let ((l_child_i, l_char_acc), (r_child_i, r_char_acc)) =
children.search_char_idx_range(start_idx, end_idx);
// Both indices point into the same child
if l_child_i == r_child_i {
let info = children.info()[l_child_i];
let (seam, mut needs_fix, new_info) =
handle_child(children, l_child_i, l_char_acc);
if children.len() > 0 {
merge_child(children, l_child_i);
// If we couldn't get all children >= minimum size, then
// we'll need to fix that later.
if children.nodes()[l_child_i.min(children.len() - 1)].is_undersized() {
needs_fix = true;
}
}
return (node_info - info + new_info, seam, needs_fix);
}
// We're dealing with more than one child.
else {
let mut needs_fix = false;
// Calculate the start..end range of nodes to be removed.
let r_child_exists: bool;
let start_i = l_child_i + 1;
let end_i = if r_char_acc + children.info()[r_child_i].chars as usize == end_idx
{
r_child_exists = false;
r_child_i + 1
} else {
r_child_exists = true;
r_child_i
};
// Remove the children
for _ in start_i..end_i {
children.remove(start_i);
}
// Handle right child
if r_child_exists {
let (_, fix, _) = handle_child(children, l_child_i + 1, r_char_acc);
needs_fix |= fix;
}
// Handle left child
let (seam, fix, _) = handle_child(children, l_child_i, l_char_acc);
needs_fix |= fix;
if children.len() > 0 {
// Handle merging
let merge_extent = 1 + if r_child_exists { 1 } else { 0 };
for i in (l_child_i..(l_child_i + merge_extent)).rev() {
merge_child(children, i);
}
// If we couldn't get all children >= minimum size, then
// we'll need to fix that later.
if children.nodes()[l_child_i.min(children.len() - 1)].is_undersized() {
needs_fix = true;
}
}
// Return
return (children.combined_info(), seam, needs_fix);
}
}
}
}
pub fn append_at_depth(&mut self, other: Arc<Node>, depth: usize) -> Option<Arc<Node>> {
if depth == 0 {
match *self {
Node::Leaf(_) => {
if !other.is_leaf() {
panic!("Tree-append siblings have differing types.");
} else {
return Some(other);
}
}
Node::Internal(ref mut children_l) => {
let mut other = other;
if let Node::Internal(ref mut children_r) = *Arc::make_mut(&mut other) {
if (children_l.len() + children_r.len()) <= MAX_CHILDREN {
for _ in 0..children_r.len() {
children_l.push(children_r.remove(0));
}
return None;
} else {
children_l.distribute_with(children_r);
// Return lower down, to avoid borrow-checker.
}
} else {
panic!("Tree-append siblings have differing types.");
}
return Some(other);
}
}
} else if let Node::Internal(ref mut children) = *self {
let last_i = children.len() - 1;
let residual =
Arc::make_mut(&mut children.nodes_mut()[last_i]).append_at_depth(other, depth - 1);
children.update_child_info(last_i);
if let Some(extra_node) = residual {
if children.len() < MAX_CHILDREN {
children.push((extra_node.text_info(), extra_node));
return None;
} else {
let r_children = children.push_split((extra_node.text_info(), extra_node));
return Some(Arc::new(Node::Internal(r_children)));
}
} else {
return None;
}
} else {
panic!("Reached leaf before getting to target depth.");
}
}
pub fn prepend_at_depth(&mut self, other: Arc<Node>, depth: usize) -> Option<Arc<Node>> {
if depth == 0 {
match *self {
Node::Leaf(_) => {
if !other.is_leaf() {
panic!("Tree-append siblings have differing types.");
} else {
return Some(other);
}
}
Node::Internal(ref mut children_r) => {
let mut other = other;
if let Node::Internal(ref mut children_l) = *Arc::make_mut(&mut other) {
if (children_l.len() + children_r.len()) <= MAX_CHILDREN {
for _ in 0..children_l.len() {
children_r.insert(0, children_l.pop());
}
return None;
} else {
children_l.distribute_with(children_r);
// Return lower down, to avoid borrow-checker.
}
} else {
panic!("Tree-append siblings have differing types.");
}
return Some(other);
}
}
} else if let Node::Internal(ref mut children) = *self {
let residual =
Arc::make_mut(&mut children.nodes_mut()[0]).prepend_at_depth(other, depth - 1);
children.update_child_info(0);
if let Some(extra_node) = residual {
if children.len() < MAX_CHILDREN {
children.insert(0, (extra_node.text_info(), extra_node));
return None;
} else {
let mut r_children =
children.insert_split(0, (extra_node.text_info(), extra_node));
std::mem::swap(children, &mut r_children);
return Some(Arc::new(Node::Internal(r_children)));
}
} else {
return None;
}
} else {
panic!("Reached leaf before getting to target depth.");
}
}
/// Splits the `Node` at char index `char_idx`, returning
/// the right side of the split.
pub fn split(&mut self, char_idx: usize) -> Node {
debug_assert!(char_idx != 0);
debug_assert!(char_idx != (self.text_info().chars as usize));
match *self {
Node::Leaf(ref mut text) => {
let byte_idx = char_to_byte_idx(text, char_idx);
Node::Leaf(text.split_off(byte_idx))
}
Node::Internal(ref mut children) => {
let (child_i, acc_info) = children.search_char_idx(char_idx);
let child_info = children.info()[child_i];
if char_idx == acc_info.chars as usize {
Node::Internal(children.split_off(child_i))
} else if char_idx == (acc_info.chars as usize + child_info.chars as usize) {
Node::Internal(children.split_off(child_i + 1))
} else {
let mut r_children = children.split_off(child_i + 1);
// Recurse
let r_node = Arc::make_mut(&mut children.nodes_mut()[child_i])
.split(char_idx - acc_info.chars as usize);
r_children.insert(0, (r_node.text_info(), Arc::new(r_node)));
children.update_child_info(child_i);
r_children.update_child_info(0);
Node::Internal(r_children)
}
}
}
}
/// Returns the chunk that contains the given byte, and the TextInfo
/// corresponding to the start of the chunk.
pub fn get_chunk_at_byte(&self, byte_idx: usize) -> (&str, TextInfo) {
let mut node = self;
let mut byte_idx = byte_idx;
let mut info = TextInfo::new();
loop {
match *node {
Node::Leaf(ref text) => {
return (text, info);
}
Node::Internal(ref children) => {
let (child_i, acc_info) = children.search_byte_idx(byte_idx);
info += acc_info;
node = &*children.nodes()[child_i];
byte_idx -= acc_info.bytes as usize;
}
}
}
}
/// Returns the chunk that contains the given char, and the TextInfo
/// corresponding to the start of the chunk.
pub fn get_chunk_at_char(&self, char_idx: usize) -> (&str, TextInfo) {
let mut node = self;
let mut char_idx = char_idx;
let mut info = TextInfo::new();
loop {
match *node {
Node::Leaf(ref text) => {
return (text, info);
}
Node::Internal(ref children) => {
let (child_i, acc_info) = children.search_char_idx(char_idx);
info += acc_info;
node = &*children.nodes()[child_i];
char_idx -= acc_info.chars as usize;
}
}
}
}
/// Returns the chunk that contains the given utf16 code unit, and the
/// TextInfo corresponding to the start of the chunk.
pub fn get_chunk_at_utf16_code_unit(&self, utf16_idx: usize) -> (&str, TextInfo) {
let mut node = self;
let mut utf16_idx = utf16_idx;
let mut info = TextInfo::new();
loop {
match *node {
Node::Leaf(ref text) => {
return (text, info);
}
Node::Internal(ref children) => {
let (child_i, acc_info) = children.search_utf16_code_unit_idx(utf16_idx);
info += acc_info;
node = &*children.nodes()[child_i];
utf16_idx -= (acc_info.chars + acc_info.utf16_surrogates) as usize;
}
}
}
}
/// Returns the chunk that contains the given line break, and the TextInfo
/// corresponding to the start of the chunk.
///
/// Note: for convenience, both the beginning and end of the rope are
/// considered line breaks for indexing.
pub fn get_chunk_at_line_break(&self, line_break_idx: usize) -> (&str, TextInfo) {
let mut node = self;
let mut line_break_idx = line_break_idx;
let mut info = TextInfo::new();
loop {
match *node {
Node::Leaf(ref text) => {
return (text, info);
}
Node::Internal(ref children) => {
let (child_i, acc_info) = children.search_line_break_idx(line_break_idx);
info += acc_info;
node = &*children.nodes()[child_i];
line_break_idx -= acc_info.line_breaks as usize;
}
}
}
}
/// Returns the TextInfo at the given char index.
#[inline(always)]
pub fn char_to_text_info(&self, char_idx: usize) -> TextInfo {
let (chunk, info) = self.get_chunk_at_char(char_idx);
let bi = char_to_byte_idx(chunk, char_idx - info.chars as usize);
TextInfo {
bytes: info.bytes + bi as Count,
chars: char_idx as Count,
utf16_surrogates: info.utf16_surrogates
+ byte_to_utf16_surrogate_idx(chunk, bi) as Count,
line_breaks: info.line_breaks + byte_to_line_idx(chunk, bi) as Count,
}
}
/// Returns the TextInfo at the given byte index.
#[inline(always)]
pub fn byte_to_text_info(&self, byte_idx: usize) -> TextInfo {
let (chunk, info) = self.get_chunk_at_byte(byte_idx);
let bi = byte_idx - info.bytes as usize;
let ci = byte_to_char_idx(chunk, byte_idx - info.bytes as usize);
TextInfo {
bytes: byte_idx as Count,
chars: info.chars + ci as Count,
utf16_surrogates: info.utf16_surrogates
+ byte_to_utf16_surrogate_idx(chunk, bi) as Count,
line_breaks: info.line_breaks + byte_to_line_idx(chunk, bi) as Count,
}
}
pub fn text_info(&self) -> TextInfo {
match *self {
Node::Leaf(ref text) => TextInfo::from_str(text),
Node::Internal(ref children) => children.combined_info(),
}
}
pub fn is_char_boundary(&self, byte_idx: usize) -> bool {
let (chunk, info) = self.get_chunk_at_byte(byte_idx);
chunk.is_char_boundary(byte_idx - info.bytes as usize)
}
#[cfg(any(feature = "cr_lines", feature = "unicode_lines"))]
pub fn is_crlf_split(&self, char_idx: usize) -> bool {
let (chunk, info) = self.get_chunk_at_char(char_idx);
let idx = char_to_byte_idx(chunk, char_idx - info.chars as usize);
if idx == 0 || idx == chunk.len() {
false
} else {
let chunk = chunk.as_bytes();
chunk[idx - 1] == 0x0D && chunk[idx] == 0x0A
}
}
//-----------------------------------------
pub fn child_count(&self) -> usize {
if let Node::Internal(ref children) = *self {
children.len()
} else {
panic!()
}
}
pub fn children(&self) -> &NodeChildren {
match *self {
Node::Internal(ref children) => children,
_ => panic!(),
}
}
pub fn children_mut(&mut self) -> &mut NodeChildren {
match *self {
Node::Internal(ref mut children) => children,
_ => panic!(),
}
}
pub fn leaf_text(&self) -> &str {
if let Node::Leaf(ref text) = *self {
text
} else {
panic!()
}
}
pub fn leaf_text_mut(&mut self) -> &mut NodeText {
if let Node::Leaf(ref mut text) = *self {
text
} else {
panic!()
}
}
pub fn is_leaf(&self) -> bool {
match *self {
Node::Leaf(_) => true,
Node::Internal(_) => false,
}
}
pub fn is_undersized(&self) -> bool {
match *self {
Node::Leaf(ref text) => text.len() < MIN_BYTES,
Node::Internal(ref children) => children.len() < MIN_CHILDREN,
}
}
/// How many nodes deep the tree is.
///
/// This counts root and leafs. For example, a single leaf node
/// has depth 1.
pub fn depth(&self) -> usize {
let mut node = self;
let mut depth = 0;
loop {
match *node {
Node::Leaf(_) => return depth,
Node::Internal(ref children) => {
depth += 1;
node = &*children.nodes()[0];
}
}
}
}
/// Debugging tool to make sure that all of the meta-data of the
/// tree is consistent with the actual data.
pub fn assert_integrity(&self) {
match *self {
Node::Leaf(_) => {}
Node::Internal(ref children) => {
for (info, node) in children.iter() {
if *info != node.text_info() {
assert_eq!(*info, node.text_info());
}
node.assert_integrity();
}
}
}
}
/// Checks that the entire tree is the same height everywhere.
pub fn assert_balance(&self) -> usize {
// Depth, child count, and leaf node emptiness
match *self {
Node::Leaf(_) => 1,
Node::Internal(ref children) => {
let first_depth = children.nodes()[0].assert_balance();
for node in &children.nodes()[1..] {
assert_eq!(node.assert_balance(), first_depth);
}
first_depth + 1
}
}
}
/// Checks that all internal nodes have the minimum number of
/// children and all non-root leaf nodes are non-empty.
pub fn assert_node_size(&self, is_root: bool) {
match *self {
Node::Leaf(ref text) => {
// Leaf size
if !is_root {
assert!(text.len() > 0);
}
}
Node::Internal(ref children) => {
// Child count
if is_root {
assert!(children.len() > 1);
} else {
assert!(children.len() >= MIN_CHILDREN);
}
for node in children.nodes() {
node.assert_node_size(false);
}
}
}
}
/// Checks to make sure that a boundary between leaf nodes (given as a byte
/// position in the rope) doesn't split a CRLF pair, and fixes it if it does.
///
/// If `must_be_boundary` is true, panics if the given byte position is
/// not on the boundary between two leaf nodes.
///
/// TODO: theoretically this can leave an internal node with fewer than
/// MIN_CHILDREN children, although it is exceedingly unlikely with any
/// remotely sane text. In the mean time, right now no code actually
/// depends on there being at least MIN_CHILDREN in an internal node.
/// But this should nevertheless get addressed at some point.
/// Probably the most straight-forward way to address this is via the
/// `fix_info_*` methods below, but I'm not totally sure.
pub fn fix_crlf_seam(&mut self, byte_pos: Count, must_be_boundary: bool) {
if let Node::Internal(ref mut children) = *self {
if byte_pos == 0 {
// Special-case 1
Arc::make_mut(&mut children.nodes_mut()[0])
.fix_crlf_seam(byte_pos, must_be_boundary);
} else if byte_pos == children.combined_info().bytes {
// Special-case 2
let (info, nodes) = children.data_mut();
Arc::make_mut(nodes.last_mut().unwrap())
.fix_crlf_seam(info.last().unwrap().bytes, must_be_boundary);
} else {
// Find the child to navigate into
let (child_i, start_info) = children.search_byte_idx(byte_pos as usize);
let start_byte = start_info.bytes;
let pos_in_child = byte_pos - start_byte;
let child_len = children.info()[child_i].bytes;
if pos_in_child == 0 || pos_in_child == child_len {
// Left or right edge, get neighbor and fix seam
let l_child_i = if pos_in_child == 0 {
debug_assert!(child_i != 0);
child_i - 1
} else {
debug_assert!(child_i < children.len());
child_i
};
// Scope for borrow
{
// Fetch the two children
let (l_child, r_child) = children.get_two_mut(l_child_i, l_child_i + 1);
let l_child_bytes = l_child.0.bytes;
let l_child = Arc::make_mut(l_child.1);
let r_child = Arc::make_mut(r_child.1);
// Get the text of the two children and fix
// the seam between them.
// Scope for borrow.
{
let (l_text, l_offset) =
l_child.get_chunk_at_byte_mut(l_child_bytes as usize);
let (r_text, r_offset) = r_child.get_chunk_at_byte_mut(0);
if must_be_boundary {
assert!(l_offset == 0 || l_offset == l_text.len());
assert!(r_offset == 0 || r_offset == r_text.len());
}
fix_segment_seam(l_text, r_text);
}
// Fix up the children's metadata after the change
// to their text.
l_child.fix_info_right();
r_child.fix_info_left();
}
// Fix up this node's metadata for those
// two children.
children.update_child_info(l_child_i);
children.update_child_info(l_child_i + 1);
// Remove the children if empty.
if children.info()[l_child_i + 1].bytes == 0 {
children.remove(l_child_i + 1);
} else if children.info()[l_child_i].bytes == 0 {
children.remove(l_child_i);
}
} else {
// Internal to child
Arc::make_mut(&mut children.nodes_mut()[child_i])
.fix_crlf_seam(pos_in_child, must_be_boundary);
children.update_child_info(child_i);
if children.info()[child_i].bytes == 0 {
children.remove(child_i);
}
}
}
}
}
/// Returns the chunk that contains the given byte, and the offset
/// of that byte within the chunk.
pub fn get_chunk_at_byte_mut(&mut self, byte_idx: usize) -> (&mut NodeText, usize) {
match *self {
Node::Leaf(ref mut text) => return (text, byte_idx),
Node::Internal(ref mut children) => {
let (child_i, acc_info) = children.search_byte_idx(byte_idx);
Arc::make_mut(&mut children.nodes_mut()[child_i])
.get_chunk_at_byte_mut(byte_idx - acc_info.bytes as usize)
}
}
}
/// Updates the tree meta-data down the left side of the tree, and removes empty
/// children as it goes as well.
fn fix_info_left(&mut self) {
match *self {
Node::Leaf(_) => {}
Node::Internal(ref mut children) => {
Arc::make_mut(&mut children.nodes_mut()[0]).fix_info_left();
children.update_child_info(0);
if children.info()[0].bytes == 0 {
children.remove(0);
}
}
}
}
/// Updates the tree meta-data down the right side of the tree, and removes empty
/// children as it goes as well.
fn fix_info_right(&mut self) {
match *self {
Node::Leaf(_) => {}
Node::Internal(ref mut children) => {
let idx = children.len() - 1;
Arc::make_mut(&mut children.nodes_mut()[idx]).fix_info_right();
children.update_child_info(idx);
if children.info()[idx].bytes == 0 {
children.remove(idx);
}
}
}
}
/// Fixes dangling nodes down the left side of the tree.
///
/// Returns whether it did anything or not that would affect the
/// parent.
pub fn zip_fix_left(&mut self) -> bool {
if let Node::Internal(ref mut children) = *self {
let mut did_stuff = false;
loop {
let do_merge = (children.len() > 1)
&& match *children.nodes()[0] {
Node::Leaf(ref text) => text.len() < MIN_BYTES,
Node::Internal(ref children2) => children2.len() < MIN_CHILDREN,
};
if do_merge {
did_stuff |= children.merge_distribute(0, 1);
}
if !Arc::make_mut(&mut children.nodes_mut()[0]).zip_fix_left() {
break;
}
}
did_stuff
} else {
false
}
}
/// Fixes dangling nodes down the right side of the tree.
///
/// Returns whether it did anything or not that would affect the
/// parent. True: did stuff, false: didn't do stuff
pub fn zip_fix_right(&mut self) -> bool {
if let Node::Internal(ref mut children) = *self {
let mut did_stuff = false;
loop {
let last_i = children.len() - 1;
let do_merge = (children.len() > 1)
&& match *children.nodes()[last_i] {
Node::Leaf(ref text) => text.len() < MIN_BYTES,
Node::Internal(ref children2) => children2.len() < MIN_CHILDREN,
};
if do_merge {
did_stuff |= children.merge_distribute(last_i - 1, last_i);
}
if !Arc::make_mut(children.nodes_mut().last_mut().unwrap()).zip_fix_right() {
break;
}
}
did_stuff
} else {
false
}
}
/// Fixes up the tree after remove_char_range() or Rope::append().
///
/// Takes the char index of the start of the removal range.
///
/// Returns whether it did anything or not that would affect the
/// parent. True: did stuff, false: didn't do stuff
pub fn fix_tree_seam(&mut self, char_idx: usize) -> bool {
if let Node::Internal(ref mut children) = *self {
let mut did_stuff = false;
loop {
// Do merging
if children.len() > 1 {
let (child_i, start_info) = children.search_char_idx(char_idx);
let mut do_merge = match *children.nodes()[child_i] {
Node::Leaf(ref text) => text.len() < MIN_BYTES,
Node::Internal(ref children2) => children2.len() < MIN_CHILDREN,
};
if child_i == 0 {
if do_merge {
did_stuff |= children.merge_distribute(0, 1);
}
} else {
do_merge = do_merge
|| (start_info.chars as usize == char_idx
&& match *children.nodes()[child_i - 1] {
Node::Leaf(ref text) => text.len() < MIN_BYTES,
Node::Internal(ref children2) => children2.len() < MIN_CHILDREN,
});
if do_merge {
let res = children.merge_distribute(child_i - 1, child_i);
did_stuff |= res
}
}
}
// Do recursion
let (child_i, start_info) = children.search_char_idx(char_idx);
if start_info.chars as usize == char_idx && child_i != 0 {
let tmp = children.info()[child_i - 1].chars as usize;
let effect_1 =
Arc::make_mut(&mut children.nodes_mut()[child_i - 1]).fix_tree_seam(tmp);
let effect_2 =
Arc::make_mut(&mut children.nodes_mut()[child_i]).fix_tree_seam(0);
if (!effect_1) && (!effect_2) {
break;
}
} else if !Arc::make_mut(&mut children.nodes_mut()[child_i])
.fix_tree_seam(char_idx - start_info.chars as usize)
{
break;
}
}
debug_assert!(children.is_info_accurate());
did_stuff
} else {
false
}
}
}
//===========================================================================
#[cfg(test)]
mod tests {
use crate::Rope;
// 133 chars, 209 bytes
const TEXT: &str = "\r\nHello there! How're you doing? It's a fine day, \
isn't it? Aren't you glad we're alive?\r\n\
こんにちは！元気ですか？日はいいですね。\
私たちが生きだって嬉しいではないか？\r\n";
#[test]
fn line_to_byte_01() {
let r = Rope::from_str(TEXT);
assert_eq!(3, r.root.line_break_count());
assert_eq!(0, r.line_to_byte(0));
assert_eq!(2, r.line_to_byte(1));
assert_eq!(93, r.line_to_byte(2));
assert_eq!(209, r.line_to_byte(3));
}
#[test]
fn line_to_char_01() {
let r = Rope::from_str(TEXT);
assert_eq!(3, r.root.line_break_count());
assert_eq!(0, r.line_to_char(0));
assert_eq!(2, r.line_to_char(1));
assert_eq!(93, r.line_to_char(2));
assert_eq!(133, r.line_to_char(3));
}
#[test]
fn crlf_corner_case_01() {
use super::Node;
use crate::tree::{NodeChildren, NodeText, MAX_BYTES};
use std::sync::Arc;
// Construct the corner case
let nodel = Node::Leaf(NodeText::from_str(&"\n".repeat(MAX_BYTES - 1)));
let noder = Node::Leaf(NodeText::from_str(&"\n".repeat(MAX_BYTES)));
let mut children = NodeChildren::new();
children.push((nodel.text_info(), Arc::new(nodel)));
children.push((noder.text_info(), Arc::new(noder)));
let root = Node::Internal(children);
let mut rope = Rope {
root: Arc::new(root),
};
assert_eq!(rope.char(0), '\n');
assert_eq!(rope.len_chars(), MAX_BYTES * 2 - 1);
// Do the potentially problematic insertion
rope.insert(MAX_BYTES - 1, "\r");
}
#[test]
fn crlf_corner_case_02() {
use super::Node;
use crate::tree::{NodeChildren, NodeText, MAX_BYTES};
use std::sync::Arc;
// Construct the corner case
let nodel = Node::Leaf(NodeText::from_str(&"\r".repeat(MAX_BYTES)));
let noder = Node::Leaf(NodeText::from_str(&"\r".repeat(MAX_BYTES - 1)));
let mut children = NodeChildren::new();
children.push((nodel.text_info(), Arc::new(nodel)));
children.push((noder.text_info(), Arc::new(noder)));
let root = Node::Internal(children);
let mut rope = Rope {
root: Arc::new(root),
};
assert_eq!(rope.char(0), '\r');
assert_eq!(rope.len_chars(), MAX_BYTES * 2 - 1);
// Do the potentially problematic insertion
rope.insert(MAX_BYTES, "\n");
}
}