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use crate::Node;
use alloc::vec;
use alloc::vec::Vec;
use core::fmt::Debug;
/// Describe the path traversal of a Node starting from the root node
///
/// The figure below shows `node_idx` in a depth first traversal.
///
/// ```text
/// .─.
/// ( 0 )
/// `-'
/// / \
/// / \
/// / \
/// ▼ ▼
/// .─. .─.
/// ( 1 ) ( 4 )
/// `-' `-'
/// / \ | \ '.
/// / \ | \ '.
/// ▼ ▼ | \ '.
/// .─. .─. ▼ ▼ ▼
/// ( 2 ) ( 3 ) .─. .─. .─.
/// `─' `─' ( 5 ) ( 6 ) ( 7 )
/// `─' `─' `─'
/// ```
///
/// The figure below shows the index of each child node relative to their parent node
///
/// ```text
/// .─.
/// ( 0 )
/// `-'
/// / \
/// / \
/// / \
/// ▼ ▼
/// .─. .─.
/// ( 0 ) ( 1 )
/// `-' `-'
/// / \ | \ '.
/// / \ | \ '.
/// ▼ ▼ | \ '.
/// .─. .─. ▼ ▼ ▼
/// ( 0 ) ( 1 ) .─. .─. .─.
/// `─' `─' ( 0 ) ( 1 ) ( 2 )
/// `─' `─' `─'
/// ```
/// The equivalent idx and path are as follows:
/// ```text
/// 0 = []
/// 1 = [0]
/// 2 = [0,0]
/// 3 = [0,1]
/// 4 = [1]
/// 5 = [1,0]
/// 6 = [1,1]
/// 7 = [1,2]
/// ```
#[derive(Debug, Clone, PartialEq, PartialOrd, Eq, Ord)]
pub struct TreePath {
/// An array of child index at each level of the dom tree.
/// The children of the nodes at each child index is traverse
/// at each traversal the first element of path is removed until
/// the path becomes empty.
/// If the path has become empty the node is said to be found.
///
/// Empty path means root node
pub path: Vec<usize>,
}
impl TreePath {
/// create a TreePath with node index `node_idx` and traversal path `path`
pub fn new(path: impl IntoIterator<Item = usize>) -> Self {
Self {
path: path.into_iter().collect(),
}
}
/// create a TreePath which starts at empty vec which is the root node of a DOM tree
pub fn root() -> Self {
Self { path: vec![] }
}
/// add a path node idx
pub fn push(&mut self, node_idx: usize) {
self.path.push(node_idx)
}
/// create a new TreePath with an added node_index
/// This is used for traversing into child elements
pub fn traverse(&self, node_idx: usize) -> Self {
let mut new_path = self.clone();
new_path.push(node_idx);
new_path
}
/// backtrack to the parent node path
pub fn backtrack(&self) -> Self {
let mut new_path = self.clone();
new_path.path.pop();
new_path
}
/// remove first node index of this treepath
/// Everytime a node is traversed, the first element should be removed
/// until no more index is in this path
pub fn remove_first(&mut self) -> usize {
self.path.remove(0)
}
/// pluck the next in line node index in this treepath
pub fn pluck(&mut self) -> usize {
self.remove_first()
}
/// returns tree if the path is empty
/// This is used for checking if the path has been traversed
pub fn is_empty(&self) -> bool {
self.path.is_empty()
}
/// find the node using the path of this tree path
pub fn find_node_by_path<'a, Ns, Tag, Leaf, Att, Val>(
&self,
node: &'a Node<Ns, Tag, Leaf, Att, Val>,
) -> Option<&'a Node<Ns, Tag, Leaf, Att, Val>>
where
Ns: PartialEq + Clone + Debug,
Tag: PartialEq + Clone + Debug,
Leaf: PartialEq + Clone + Debug,
Att: PartialEq + Clone + Debug,
Val: PartialEq + Clone + Debug,
{
let mut path = self.clone();
traverse_node_by_path(node, &mut path)
}
}
impl<const N: usize> From<[usize; N]> for TreePath {
fn from(array: [usize; N]) -> Self {
Self {
path: array.to_vec(),
}
}
}
impl From<Vec<usize>> for TreePath {
fn from(vec: Vec<usize>) -> Self {
Self { path: vec }
}
}
fn traverse_node_by_path<'a, Ns, Tag, Leaf, Att, Val>(
node: &'a Node<Ns, Tag, Leaf, Att, Val>,
path: &mut TreePath,
) -> Option<&'a Node<Ns, Tag, Leaf, Att, Val>>
where
Ns: PartialEq + Clone + Debug,
Tag: PartialEq + Clone + Debug,
Leaf: PartialEq + Clone + Debug,
Att: PartialEq + Clone + Debug,
Val: PartialEq + Clone + Debug,
{
if path.path.is_empty() {
Some(node)
} else {
let idx = path.path.remove(0);
if let Some(child) = node.children().get(idx) {
traverse_node_by_path(child, path)
} else {
None
}
}
}
#[cfg(test)]
mod tests {
use super::*;
use crate::*;
use alloc::format;
use alloc::string::String;
use alloc::string::ToString;
type MyNode = Node<
&'static str,
&'static str,
&'static str,
&'static str,
&'static str,
>;
#[test]
fn test_traverse() {
let path = TreePath::from([0]);
assert_eq!(path.traverse(1), TreePath::from([0, 1]));
}
fn sample_node() -> MyNode {
let node: MyNode = element(
"div",
vec![attr("class", "[]"), attr("id", "0")],
vec![
element(
"div",
vec![attr("class", "[0]"), attr("id", "1")],
vec![
element(
"div",
vec![attr("class", "[0,0]"), attr("id", "2")],
vec![],
),
element(
"div",
vec![attr("class", "[0,1]"), attr("id", "3")],
vec![],
),
],
),
element(
"div",
vec![attr("class", "[1]"), attr("id", "4")],
vec![
element(
"div",
vec![attr("class", "[1,0]"), attr("id", "5")],
vec![],
),
element(
"div",
vec![attr("class", "[1,1]"), attr("id", "6")],
vec![],
),
element(
"div",
vec![attr("class", "[1,2]"), attr("id", "7")],
vec![],
),
],
),
],
);
node
}
// index is the index of this code with respect to it's sibling
fn assert_traverse_match(
node: &MyNode,
node_idx: &mut usize,
path: Vec<usize>,
) {
let id = node.attribute_value(&"id").unwrap()[0];
let class = node.attribute_value(&"class").unwrap()[0];
assert_eq!(id.to_string(), node_idx.to_string());
assert_eq!(class.to_string(), format_vec(&path));
for (i, child) in node.children().iter().enumerate() {
*node_idx += 1;
let mut child_path = path.clone();
child_path.push(i);
assert_traverse_match(child, node_idx, child_path);
}
}
fn traverse_tree_path(
node: &MyNode,
path: &TreePath,
node_idx: &mut usize,
) {
let id = node.attribute_value(&"id").unwrap()[0];
let class = node.attribute_value(&"class").unwrap()[0];
assert_eq!(id.to_string(), node_idx.to_string());
assert_eq!(class.to_string(), format_vec(&path.path));
for (i, child) in node.children().iter().enumerate() {
*node_idx += 1;
let mut child_path = path.clone();
child_path.path.push(i);
traverse_tree_path(child, &child_path, node_idx);
}
}
fn format_vec(v: &[usize]) -> String {
format!(
"[{}]",
v.iter()
.map(|v| v.to_string())
.collect::<Vec<_>>()
.join(",")
)
}
#[test]
fn should_match_paths() {
let node = sample_node();
assert_traverse_match(&node, &mut 0, vec![]);
traverse_tree_path(&node, &TreePath::new(vec![]), &mut 0);
}
#[test]
fn should_find_root_node() {
let node = sample_node();
let path = TreePath::new(vec![]);
let root = path.find_node_by_path(&node);
assert_eq!(Some(&node), root);
}
#[test]
fn should_find_node1() {
let node = sample_node();
let path = TreePath::new(vec![0]);
let found = path.find_node_by_path(&node);
let expected = element(
"div",
vec![attr("class", "[0]"), attr("id", "1")],
vec![
element(
"div",
vec![attr("class", "[0,0]"), attr("id", "2")],
vec![],
),
element(
"div",
vec![attr("class", "[0,1]"), attr("id", "3")],
vec![],
),
],
);
assert_eq!(Some(&expected), found);
}
#[test]
fn should_find_node2() {
let node = sample_node();
let path = TreePath::new(vec![0, 0]);
let found = path.find_node_by_path(&node);
let expected = element(
"div",
vec![attr("class", "[0,0]"), attr("id", "2")],
vec![],
);
assert_eq!(Some(&expected), found);
}
#[test]
fn should_find_node3() {
let node = sample_node();
let path = TreePath::new(vec![0, 1]);
let found = path.find_node_by_path(&node);
let expected = element(
"div",
vec![attr("class", "[0,1]"), attr("id", "3")],
vec![],
);
assert_eq!(Some(&expected), found);
}
#[test]
fn should_find_node4() {
let node = sample_node();
let path = TreePath::new(vec![1]);
let found = path.find_node_by_path(&node);
let expected = element(
"div",
vec![attr("class", "[1]"), attr("id", "4")],
vec![
element(
"div",
vec![attr("class", "[1,0]"), attr("id", "5")],
vec![],
),
element(
"div",
vec![attr("class", "[1,1]"), attr("id", "6")],
vec![],
),
element(
"div",
vec![attr("class", "[1,2]"), attr("id", "7")],
vec![],
),
],
);
assert_eq!(Some(&expected), found);
}
#[test]
fn should_find_node5() {
let node = sample_node();
let path = TreePath::new(vec![1, 0]);
let found = path.find_node_by_path(&node);
let expected = element(
"div",
vec![attr("class", "[1,0]"), attr("id", "5")],
vec![],
);
assert_eq!(Some(&expected), found);
}
#[test]
fn should_find_node6() {
let node = sample_node();
let path = TreePath::new(vec![1, 1]);
let found = path.find_node_by_path(&node);
let expected = element(
"div",
vec![attr("class", "[1,1]"), attr("id", "6")],
vec![],
);
assert_eq!(Some(&expected), found);
}
#[test]
fn should_find_none_in_013() {
let node = sample_node();
let path = TreePath::new(vec![0, 1, 3]);
let found = path.find_node_by_path(&node);
assert_eq!(None, found);
}
#[test]
fn should_find_none_in_00000() {
let node = sample_node();
let path = TreePath::new(vec![0, 0, 0, 0]);
let found = path.find_node_by_path(&node);
assert_eq!(None, found);
}
#[test]
fn should_find_none_in_007() {
let node = sample_node();
let path = TreePath::new(vec![0, 0, 7]);
let bond = path.find_node_by_path(&node);
assert_eq!(None, bond);
}
}