Fix get_header_level_toc_vec
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1 changed files with 76 additions and 23 deletions
99
src/epub.rs
99
src/epub.rs
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@ -279,48 +279,101 @@ fn generate_header_ids(root_node: &NodeRef) {
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/// Returns a vector of `TocElement` from a NodeRef used for adding to the Table of Contents for navigation
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/// Returns a vector of `TocElement` from a NodeRef used for adding to the Table of Contents for navigation
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fn get_header_level_toc_vec(content_url: &str, article: &NodeRef) -> Vec<TocElement> {
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fn get_header_level_toc_vec(content_url: &str, article: &NodeRef) -> Vec<TocElement> {
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generate_header_ids(article);
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// Depth starts from 1
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const HEADER_LEVEL_MAX_DEPTH: usize = 4;
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let mut headers_vec: Vec<TocElement> = Vec::new();
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let mut headers_vec = Vec::new();
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let mut header_levels = HashMap::with_capacity(HEADER_LEVEL_MAX_DEPTH);
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let mut header_levels = HashMap::new();
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header_levels.insert("h1", 1);
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header_levels.insert("h1", 1);
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header_levels.insert("h2", 2);
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header_levels.insert("h2", 2);
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header_levels.insert("h3", 3);
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header_levels.insert("h3", 3);
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header_levels.insert("h4", 4);
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header_levels.insert("h4", 4);
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generate_header_ids(article);
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let headings = article
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let headings = article
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.select("h1, h2, h3, h4")
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.select("h1, h2, h3, h4")
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.expect("Unable to create selector for headings");
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.expect("Unable to create selector for headings");
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let mut last_toc_elem_level: Option<i32> = None;
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// The header list will be generated using some sort of backtracking algorithm
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// There will be a stack of maximum size 4 (since it only goes to h4 now)
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let mut stack: Vec<Option<TocElement>> = std::iter::repeat(None)
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.take(HEADER_LEVEL_MAX_DEPTH)
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.collect::<_>();
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for heading in headings {
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for heading in headings {
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// TODO: Create a new function that adds an id attribute to heading tags before this function is called
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let elem_attrs = heading.attributes.borrow();
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let elem_name: &str = &heading.name.local;
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let elem_name: &str = &heading.name.local;
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let elem_level = header_levels[elem_name];
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let attrs = heading.attributes.borrow();
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let id = elem_attrs.get("id").map(|val| val.to_string()).unwrap();
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let id = attrs
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let toc = TocElement::new(
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.get("id")
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format!("{}#{}", content_url, id),
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.map(ToOwned::to_owned)
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replace_escaped_characters(&heading.text_contents()),
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.expect("Unable to get id value in get_header_level_toc_vec");
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);
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let url = format!("{}#{}", content_url, id);
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if let Some(last_elem_level) = last_toc_elem_level {
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let level = header_levels[elem_name];
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if elem_level <= last_elem_level {
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let index = level - 1;
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last_toc_elem_level = Some(elem_level);
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headers_vec.push(toc);
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if let Some(mut existing_toc) = stack.get_mut(index).take().cloned().flatten() {
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// If a toc element already exists at that header level, consume all the toc elements
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// of a lower hierarchy e.g if the existing toc is a h2, then the h3 and h4 in the stack
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// will be consumed.
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// We collapse the children by folding from the right to the left of the stack.
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let descendants_levels = HEADER_LEVEL_MAX_DEPTH - level;
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let folded_descendants = stack
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.iter_mut()
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.rev()
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.take(descendants_levels)
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.map(|toc_elem| toc_elem.take())
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.filter(|toc_elem| toc_elem.is_some())
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.map(|toc_elem| toc_elem.unwrap())
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.reduce(|child, parent| parent.child(child));
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if let Some(child) = folded_descendants {
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existing_toc = existing_toc.child(child);
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};
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// Find the nearest ancestor to embed into.
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// If this toc_elem was a h1, then just add it to the headers_vec
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if index == 0 {
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headers_vec.push(existing_toc);
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} else {
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} else {
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match headers_vec.last_mut() {
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// Otherwise, find the nearest ancestor to add it to. If none exists, add it to the headers_vec
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Some(toc_elem) => *toc_elem = toc_elem.clone().child(toc),
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let first_ancestor = stack
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_ => unreachable!(),
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.iter_mut()
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.take(level - 1)
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.map(|toc_elem| toc_elem.as_mut())
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.rfind(|toc_elem| toc_elem.is_some())
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.flatten();
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match first_ancestor {
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Some(ancestor_toc_elem) => {
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*ancestor_toc_elem = ancestor_toc_elem.clone().child(existing_toc);
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}
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None => {
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headers_vec.push(existing_toc);
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}
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}
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}
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}
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}
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} else {
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}
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last_toc_elem_level = Some(elem_level);
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headers_vec.push(toc);
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if let Some(toc_elem) = stack.get_mut(index) {
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*toc_elem = Some(TocElement::new(
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url,
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replace_escaped_characters(&heading.text_contents()),
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));
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}
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}
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}
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}
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let folded_stack = stack
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.into_iter()
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.rev()
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.filter(|toc_elem| toc_elem.is_some())
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.map(|opt_toc_elem| opt_toc_elem.unwrap())
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.reduce(|child, parent| parent.child(child));
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if let Some(toc_elem) = folded_stack {
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headers_vec.push(toc_elem)
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}
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headers_vec
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headers_vec
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}
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}
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#[cfg(test)]
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#[cfg(test)]
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