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use std::collections::HashMap;
use crate::types::BodyStructure;
/// An utility parser helping to find the appropriate
/// section part from a FETCH response.
pub struct BodyStructParser<'a> {
root: &'a BodyStructure<'a>,
prefix: Vec<u32>,
iter: u32,
map: HashMap<Vec<u32>, &'a BodyStructure<'a>>,
}
impl<'a> BodyStructParser<'a> {
/// Returns a new parser
///
/// # Arguments
///
/// * `root` - The root of the `BodyStructure response.
pub fn new(root: &'a BodyStructure<'a>) -> Self {
let mut parser = BodyStructParser {
root,
prefix: vec![],
iter: 1,
map: HashMap::new(),
};
parser.parse(parser.root);
parser
}
/// Search particular element within the bodystructure.
///
/// # Arguments
///
/// * `func` - The filter used to search elements within the bodystructure.
pub fn search<F>(&self, func: F) -> Option<Vec<u32>>
where
F: Fn(&'a BodyStructure<'a>) -> bool,
{
let elem: Vec<_> = self
.map
.iter()
.filter_map(|(k, v)| {
if func(v) {
let slice: &[u32] = k;
Some(slice)
} else {
None
}
})
.collect();
elem.first().map(|a| a.to_vec())
}
/// Reetr
fn parse(&mut self, node: &'a BodyStructure) {
match node {
BodyStructure::Multipart { bodies, .. } => {
let vec = self.prefix.clone();
self.map.insert(vec, node);
for (i, n) in bodies.iter().enumerate() {
self.iter += i as u32;
self.prefix.push(self.iter);
self.parse(n);
self.prefix.pop();
}
self.iter = 1;
}
_ => {
let vec = self.prefix.clone();
self.map.insert(vec, node);
}
};
}
}