blog: refactor: rewrite more transform as iterator operations

This commit is contained in:
Peter Cai 2020-04-18 16:35:38 +08:00
parent 994da996bc
commit 10339daf09
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GPG Key ID: 71F5FB4E4F3FD54F
1 changed files with 27 additions and 16 deletions

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@ -9,6 +9,7 @@ use crate::utils::*;
use js_sys::{JsString, RegExp};
use pulldown_cmark::*;
use serde::{Serialize, Deserialize};
use std::future::Future;
use std::vec::Vec;
use wasm_bindgen::JsCast;
use wasm_bindgen::closure::Closure;
@ -231,6 +232,22 @@ impl PostContentCache {
}
}
fn transform_tags<'ev>(
parser: impl 'ev + Iterator<Item = Event<'ev>>
) -> impl 'ev + Iterator<Item = impl Future<Output = Event<'ev>>> {
parser.map(|mut ev| {
async {
match ev {
Event::Start(ref mut tag) | Event::End(ref mut tag) => {
Self::transform_tag(tag).await;
ev
},
_ => ev
}
}
})
}
fn transform_code_block_highlight<'iter, 'ev>(
parser: impl Iterator<Item = Event<'ev>>
) -> impl Iterator<Item = Event<'ev>> {
@ -309,26 +326,20 @@ impl PostContentCache {
// Despite the signature, this function BLOCKS
// async only comes from digesting via SubtleCrypto
pub async fn render(post: &Post) -> PostContentCache {
// We have to first collect all events into a vector
// because we need to asynchronously transform the events
// which could not be done through mapping on iterators
let mut parser: Vec<Event> = Parser::new_ext(&post.content, Options::all()).collect();
for ev in parser.iter_mut() {
match ev {
Event::Start(tag) | Event::End(tag) => {
Self::transform_tag(tag).await;
},
_ => ()
};
}
// Now some pure iterator operations
let parser = parser.into_iter();
let parser = Parser::new_ext(&post.content, Options::all());
// Apply code highlighting via Highlight.js
let parser = Self::transform_code_block_highlight(parser);
// Apply async tag transform (resulting in an iterator of Futures)
let parser = Self::transform_tags(parser);
// Await on every Future in the queue to convert them back as Events
let mut events: Vec<Event> = vec![];
for ev in parser {
events.push(ev.await);
}
let mut html_output = String::new();
html::push_html(&mut html_output, parser);
html::push_html(&mut html_output, events.into_iter());
html_output = Self::transform_html(html_output);
PostContentCache {
uuid: post.uuid.clone(),