css-inline 0.10.0

High-performance library for inlining CSS into HTML 'style' attributes
Documentation 
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use super::{
    document::Document,
    node::{ElementData, NodeData, NodeId},
};
use html5ever::{
    local_name,
    serialize::{serialize, Serialize, SerializeOpts, Serializer, TraversalScope},
};
use std::{io, io::Write};

pub(crate) fn serialize_to<W: Write>(
    document: &Document,
    writer: &mut W,
    keep_style_tags: bool,
    keep_link_tags: bool,
) -> io::Result<()> {
    let sink = Sink::new(
        document,
        NodeId::document_id(),
        keep_style_tags,
        keep_link_tags,
    );
    serialize(writer, &sink, SerializeOpts::default())
}

/// Intermediary structure for serializing an HTML document.
struct Sink<'a> {
    document: &'a Document,
    node: NodeId,
    keep_style_tags: bool,
    keep_link_tags: bool,
}

impl<'a> Sink<'a> {
    fn new(
        document: &'a Document,
        node: NodeId,
        keep_style_tags: bool,
        keep_link_tags: bool,
    ) -> Sink<'a> {
        Sink {
            document,
            node,
            keep_style_tags,
            keep_link_tags,
        }
    }
    #[inline]
    fn for_node(&self, node: NodeId) -> Sink<'a> {
        Sink::new(
            self.document,
            node,
            self.keep_style_tags,
            self.keep_link_tags,
        )
    }
    #[inline]
    fn data(&self) -> &NodeData {
        &self.document[self.node].data
    }
    #[inline]
    fn should_skip_element(&self, element: &ElementData) -> bool {
        if element.name.local == local_name!("style") {
            !self.keep_style_tags
        } else if element.name.local == local_name!("link")
            && element.attributes.get(local_name!("rel")) == Some("stylesheet")
        {
            !self.keep_link_tags
        } else {
            false
        }
    }
    fn serialize_children<S: Serializer>(&self, serializer: &mut S) -> io::Result<()> {
        for child in self.document.children(self.node) {
            self.for_node(child)
                .serialize(serializer, TraversalScope::IncludeNode)?;
        }
        Ok(())
    }
}

impl<'a> Serialize for Sink<'a> {
    fn serialize<S>(&self, serializer: &mut S, _: TraversalScope) -> io::Result<()>
    where
        S: Serializer,
    {
        match self.data() {
            NodeData::Element { element, .. } => {
                if self.should_skip_element(element) {
                    return Ok(());
                }
                serializer.start_elem(
                    element.name.clone(),
                    element
                        .attributes
                        .map
                        .iter()
                        .map(|(key, value)| (key, &**value)),
                )?;

                self.serialize_children(serializer)?;

                serializer.end_elem(element.name.clone())?;
                Ok(())
            }
            NodeData::Document => self.serialize_children(serializer),
            NodeData::Doctype { name } => serializer.write_doctype(name),
            NodeData::Text { text: content } => serializer.write_text(content),
            NodeData::Comment { text } => serializer.write_comment(text),
            NodeData::ProcessingInstruction { target, data } => {
                serializer.write_processing_instruction(target, data)
            }
        }
    }
}

#[cfg(test)]
mod tests {
    use super::Document;

    #[test]
    fn test_serialize() {
        let doc = Document::parse_with_options(b"<html><head><title>Test</title><style>h1 { color:blue; }</style><style>h1 { color:red; }</style></head>", 0);
        let mut buffer = Vec::new();
        doc.serialize(&mut buffer, true, false)
            .expect("Should not fail");
        assert_eq!(buffer, b"<html><head><title>Test</title><style>h1 { color:blue; }</style><style>h1 { color:red; }</style></head><body></body></html>");
    }

    #[test]
    fn test_skip_style_tags() {
        let doc = Document::parse_with_options(b"<html><head><title>Test</title><style>h1 { color:blue; }</style><style>h1 { color:red; }</style></head>", 0);
        let mut buffer = Vec::new();
        doc.serialize(&mut buffer, false, false)
            .expect("Should not fail");
        assert_eq!(
            buffer,
            b"<html><head><title>Test</title></head><body></body></html>"
        );
    }
}